1
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Mastrogiovanni M, Martínez-Navarro FJ, Bowman TV, Cayuela ML. Inflammation in Development and Aging: Insights from the Zebrafish Model. Int J Mol Sci 2024; 25:2145. [PMID: 38396822 PMCID: PMC10889087 DOI: 10.3390/ijms25042145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/25/2024] Open
Abstract
Zebrafish are an emergent animal model to study human diseases due to their significant genetic similarity to humans, swift development, and genetic manipulability. Their utility extends to the exploration of the involvement of inflammation in host defense, immune responses, and tissue regeneration. Additionally, the zebrafish model system facilitates prompt screening of chemical compounds that affect inflammation. This study explored the diverse roles of inflammatory pathways in zebrafish development and aging. Serving as a crucial model, zebrafish provides insights into the intricate interplay of inflammation in both developmental and aging contexts. The evidence presented suggests that the same inflammatory signaling pathways often play instructive or beneficial roles during embryogenesis and are associated with malignancies in adults.
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Affiliation(s)
- Marta Mastrogiovanni
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Gottesman Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Francisco Juan Martínez-Navarro
- Grupo de Telomerasa, Cáncer y Envejecimiento, Hospital Clínico Universitario Virgen de la Arrixaca, 30120 Murcia, Spain
- Instituto Murciano de Investigación Biosanitaria-Arrixaca, 30120 Murcia, Spain
| | - Teresa V. Bowman
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Gottesman Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - María L. Cayuela
- Grupo de Telomerasa, Cáncer y Envejecimiento, Hospital Clínico Universitario Virgen de la Arrixaca, 30120 Murcia, Spain
- Instituto Murciano de Investigación Biosanitaria-Arrixaca, 30120 Murcia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, 30100 Murcia, Spain
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2
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Yang S, Cao S, Xu X, Li Q, Li J, Guo J, Wang F, Bao Y, Jiang Z, Zhang T, Wang L, Sun S. adducin 1 is essential for the survival of erythroid precursors via regulating p53 transcription in zebrafish. iScience 2023; 26:107516. [PMID: 37636049 PMCID: PMC10448115 DOI: 10.1016/j.isci.2023.107516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 06/13/2023] [Accepted: 07/26/2023] [Indexed: 08/29/2023] Open
Abstract
Adducin 1 (Add1) is known as a membrane cytoskeletal protein, but its nuclear function remains unclear. In this study, we generated add1-deficient zebrafish to investigate its role in hematopoiesis. Lack of add1 impaired both primitive and definitive hematopoiesis, preventing healthy erythrocyte development. RNA sequencing revealed activation of the p53 pathway in add1-depleted erythroblast cells, leading to apoptosis at the 14-somites stage and 24 hpf. Interestingly, partial rescue of the anemic phenotype and apoptosis was observed with p53 insufficiency. Mechanistically, ADD1 was found to regulate promoter activity. These findings demonstrate that Add1 plays a crucial role in zebrafish erythropoiesis, involving the p53-mediated apoptotic pathway, expanding its regulatory role beyond cytoskeletal functions.
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Affiliation(s)
- Shuyan Yang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Shanhu Cao
- Department of Biochemistry and Molecular Biology, Key Laboratory of Medical Biotechnology of Hebei Province, Cardiovascular Medical Science Center, Hebei Medical University, Shijiazhuang 050017, China
| | - Xuebing Xu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang, China
| | - Quan Li
- Beijing Institutes of Life Science Chinese Academy of Sciences, Beijing 100101, China
| | - Jianting Li
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan 030001, China
| | - Jin Guo
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Fang Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Yihua Bao
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Zean Jiang
- Department of Biochemistry and Molecular Biology, Key Laboratory of Medical Biotechnology of Hebei Province, Cardiovascular Medical Science Center, Hebei Medical University, Shijiazhuang 050017, China
| | - Ting Zhang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Li Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Shaoguang Sun
- Department of Biochemistry and Molecular Biology, Key Laboratory of Medical Biotechnology of Hebei Province, Cardiovascular Medical Science Center, Hebei Medical University, Shijiazhuang 050017, China
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3
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Amin A, Morello M, Petrara MR, Rizzo B, Argenton F, De Rossi A, Giunco S. Short-Term TERT Inhibition Impairs Cellular Proliferation via a Telomere Length-Independent Mechanism and Can Be Exploited as a Potential Anticancer Approach. Cancers (Basel) 2023; 15:2673. [PMID: 37345011 DOI: 10.3390/cancers15102673] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/21/2023] [Accepted: 05/04/2023] [Indexed: 06/23/2023] Open
Abstract
Telomerase reverse transcriptase (TERT), the catalytic component of telomerase, may also contribute to carcinogenesis via telomere-length independent mechanisms. Our previous in vitro and in vivo studies demonstrated that short-term telomerase inhibition by BIBR1532 impairs cell proliferation without affecting telomere length. Here, we show that the impaired cell cycle progression following short-term TERT inhibition by BIBR1532 in in vitro models of B-cell lymphoproliferative disorders, i.e., Epstein-Barr virus (EBV)-immortalized lymphoblastoid cell lines (LCLs), and B-cell malignancies, i.e., Burkitt's lymphoma (BL) cell lines, is characterized by a significant reduction in NF-κB p65 nuclear levels leading to the downregulation of its target gene MYC. MYC downregulation was associated with increased expression and nuclear localization of P21, thus promoting its cell cycle inhibitory function. Consistently, treatment with BIBR1532 in wild-type zebrafish embryos significantly decreased Myc and increased p21 expression. The combination of BIBR1532 with antineoplastic drugs (cyclophosphamide or fludarabine) significantly reduced xenografted cells' proliferation rate compared to monotherapy in the zebrafish xenograft model. Overall, these findings indicate that short-term inhibition of TERT impairs cell growth through the downregulation of MYC via NF-κB signalling and supports the use of TERT inhibitors in combination with antineoplastic drugs as an efficient anticancer strategy.
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Affiliation(s)
- Aamir Amin
- Department of Surgery, Oncology and Gastroenterology, Section of Oncology and Immunology, University of Padova, 35128 Padova, Italy
| | - Marzia Morello
- Immunology and Diagnostic Molecular Oncology Unit, Veneto Institute of Oncology IOV-IRCCS, 35128 Padova, Italy
| | - Maria Raffaella Petrara
- Department of Surgery, Oncology and Gastroenterology, Section of Oncology and Immunology, University of Padova, 35128 Padova, Italy
| | - Beatrice Rizzo
- Immunology and Diagnostic Molecular Oncology Unit, Veneto Institute of Oncology IOV-IRCCS, 35128 Padova, Italy
| | | | - Anita De Rossi
- Department of Surgery, Oncology and Gastroenterology, Section of Oncology and Immunology, University of Padova, 35128 Padova, Italy
- Immunology and Diagnostic Molecular Oncology Unit, Veneto Institute of Oncology IOV-IRCCS, 35128 Padova, Italy
| | - Silvia Giunco
- Department of Surgery, Oncology and Gastroenterology, Section of Oncology and Immunology, University of Padova, 35128 Padova, Italy
- Immunology and Diagnostic Molecular Oncology Unit, Veneto Institute of Oncology IOV-IRCCS, 35128 Padova, Italy
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4
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El Maï M, Bird M, Allouche A, Targen S, Şerifoğlu N, Lopes-Bastos B, Guigonis JM, Kang D, Pourcher T, Yue JX, Ferreira MG. Gut-specific telomerase expression counteracts systemic aging in telomerase-deficient zebrafish. NATURE AGING 2023; 3:567-584. [PMID: 37142828 DOI: 10.1038/s43587-023-00401-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/21/2023] [Indexed: 05/06/2023]
Abstract
Telomere shortening is a hallmark of aging and is counteracted by telomerase. As in humans, the zebrafish gut is one of the organs with the fastest rate of telomere decline, triggering early tissue dysfunction during normal zebrafish aging and in prematurely aged telomerase mutants. However, whether telomere-dependent aging of an individual organ, the gut, causes systemic aging is unknown. Here we show that tissue-specific telomerase expression in the gut can prevent telomere shortening and rescues premature aging of tert-/-. Induction of telomerase rescues gut senescence and low cell proliferation, while restoring tissue integrity, inflammation and age-dependent microbiota dysbiosis. Averting gut aging causes systemic beneficial impacts, rescuing aging of distant organs such as reproductive and hematopoietic systems. Conclusively, we show that gut-specific telomerase expression extends the lifespan of tert-/- by 40%, while ameliorating natural aging. Our work demonstrates that gut-specific rescue of telomerase expression leading to telomere elongation is sufficient to systemically counteract aging in zebrafish.
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Affiliation(s)
- Mounir El Maï
- Institute for Research on Cancer and Aging of Nice (IRCAN), CNRS UMR7284, INSERM U1081, Université Côte d'Azur, Nice, France
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Malia Bird
- Institute for Research on Cancer and Aging of Nice (IRCAN), CNRS UMR7284, INSERM U1081, Université Côte d'Azur, Nice, France
| | - Asma Allouche
- Institute for Research on Cancer and Aging of Nice (IRCAN), CNRS UMR7284, INSERM U1081, Université Côte d'Azur, Nice, France
| | - Seniye Targen
- Institute for Research on Cancer and Aging of Nice (IRCAN), CNRS UMR7284, INSERM U1081, Université Côte d'Azur, Nice, France
| | - Naz Şerifoğlu
- Institute for Research on Cancer and Aging of Nice (IRCAN), CNRS UMR7284, INSERM U1081, Université Côte d'Azur, Nice, France
| | - Bruno Lopes-Bastos
- Institute for Research on Cancer and Aging of Nice (IRCAN), CNRS UMR7284, INSERM U1081, Université Côte d'Azur, Nice, France
| | - Jean-Marie Guigonis
- Laboratory Transporter in Imaging and Radiotherapy in Oncology, Institut des Sciences du Vivant Frederic Joliot, Commissariat à l'Energie Atomique et aux Energies Alternatives, Université Côte d'Azur, Nice, France
| | - Da Kang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Thierry Pourcher
- Laboratory Transporter in Imaging and Radiotherapy in Oncology, Institut des Sciences du Vivant Frederic Joliot, Commissariat à l'Energie Atomique et aux Energies Alternatives, Université Côte d'Azur, Nice, France
| | - Jia-Xing Yue
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Miguel Godinho Ferreira
- Institute for Research on Cancer and Aging of Nice (IRCAN), CNRS UMR7284, INSERM U1081, Université Côte d'Azur, Nice, France.
- Instituto Gulbenkian de Ciência, Oeiras, Portugal.
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5
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Sanpedro-Luna JA, Jacinto-Vázquez JJ, Anastacio-Marcelino E, Posadas-Gutiérrez CM, Olmos-Pineda I, González-Bernal JA, Carcaño-Montiel M, Vega-Alvarado L, Vázquez-Cruz C, Sánchez-Alonso P. Telomerase RNA plays a major role in the completion of the life cycle in Ustilago maydis and shares conserved domains with other Ustilaginales. PLoS One 2023; 18:e0281251. [PMID: 36952474 PMCID: PMC10035886 DOI: 10.1371/journal.pone.0281251] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/18/2023] [Indexed: 03/25/2023] Open
Abstract
The RNA subunit of telomerase is an essential component whose primary sequence and length are poorly conserved among eukaryotic organisms. The phytopathogen Ustilago maydis is a dimorphic fungus of the order Ustilaginales. We analyzed several species of Ustilaginales to computationally identify the TElomere RNA (TER) gene ter1. To confirm the identity of the TER gene, we disrupted the gene and characterized telomerase-negative mutants. Similar to catalytic TERT mutants, ter1Δ mutants exhibit phenotypes of growth delay, telomere shortening and low replicative potential. ter1-disrupted mutants were unable to infect maize seedlings in heterozygous crosses and showed defects such as cell cycle arrest and segregation failure. We concluded that ter1, which encodes the TER subunit of the telomerase of U. maydis, have similar and perhaps more extensive functions than trt1.
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Affiliation(s)
- Juan Antonio Sanpedro-Luna
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - José Juan Jacinto-Vázquez
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Estela Anastacio-Marcelino
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | | | - Iván Olmos-Pineda
- Facultad de Ciencias de la Computación, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Jesús Antonio González-Bernal
- Department of Computer Science and Engineering, The University of Texas Arlington, Arlington, Texas, United States of America
| | - Moisés Carcaño-Montiel
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Leticia Vega-Alvarado
- Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, México, México
| | - Candelario Vázquez-Cruz
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Patricia Sánchez-Alonso
- Instituto de Ciencias, Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, México
- Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
- * E-mail:
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6
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Giunco S, Zangrossi M, Dal Pozzolo F, Celeghin A, Ballin G, Petrara MR, Amin A, Argenton F, Godinho Ferreira M, De Rossi A. Anti-Proliferative and Pro-Apoptotic Effects of Short-Term Inhibition of Telomerase In Vivo and in Human Malignant B Cells Xenografted in Zebrafish. Cancers (Basel) 2020; 12:cancers12082052. [PMID: 32722398 PMCID: PMC7463531 DOI: 10.3390/cancers12082052] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 07/20/2020] [Accepted: 07/23/2020] [Indexed: 12/11/2022] Open
Abstract
Besides its canonical role in stabilizing telomeres, telomerase reverse transcriptase (TERT) may promote tumor growth/progression through extra-telomeric functions. Our previous in vitro studies demonstrated that short-term TERT inhibition by BIBR1532 (BIBR), an inhibitor of TERT catalytic activity, negatively impacts cell proliferation and viability via telomeres’ length-independent mechanism. Here we evaluate the anti-proliferative and pro-apoptotic effects of short-term telomerase inhibition in vivo in wild-type (wt) and tert mutant (terthu3430/hu3430; tert−/−) zebrafish embryos, and in malignant human B cells xenografted in casper zebrafish embryos. Short-term Tert inhibition by BIBR in wt embryos reduced cell proliferation, induced an accumulation of cells in S-phase and ultimately led to apoptosis associated with the activation of DNA damage response; all these effects were unrelated to telomere shortening/dysfunction. BIBR treatment showed no effects in tert−/− embryos. Xenografted untreated malignant B cells proliferated in zebrafish embryos, while BIBR pretreated cells constantly decreased and were significantly less than those in the controls from 24 to up to 72 h after xenotransplantation. Additionally, xenografted tumor cells, treated with BIBR prior- or post-transplantation, displayed a significant higher apoptotic rate compared to untreated control cells. In conclusion, our data demonstrate that short-term telomerase inhibition impairs proliferation and viability in vivo and in human malignant B cells xenografted in zebrafish, thus supporting therapeutic applications of TERT inhibitors in human malignancies.
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Affiliation(s)
- Silvia Giunco
- Oncology and Immunology Section, Department of Surgery, Oncology and Gastroenterology, University of Padova, 35128 Padova, Italy; (M.Z.); (A.C.); (G.B.); (M.R.P.); (A.A.); (A.D.R.)
- Correspondence: ; Tel.: +39-049-821-5831
| | - Manuela Zangrossi
- Oncology and Immunology Section, Department of Surgery, Oncology and Gastroenterology, University of Padova, 35128 Padova, Italy; (M.Z.); (A.C.); (G.B.); (M.R.P.); (A.A.); (A.D.R.)
| | - Francesca Dal Pozzolo
- Immunology and Diagnostic Molecular Oncology Unit, Veneto Institute of Oncology IOV–IRCCS, 35128 Padova, Italy;
| | - Andrea Celeghin
- Oncology and Immunology Section, Department of Surgery, Oncology and Gastroenterology, University of Padova, 35128 Padova, Italy; (M.Z.); (A.C.); (G.B.); (M.R.P.); (A.A.); (A.D.R.)
| | - Giovanni Ballin
- Oncology and Immunology Section, Department of Surgery, Oncology and Gastroenterology, University of Padova, 35128 Padova, Italy; (M.Z.); (A.C.); (G.B.); (M.R.P.); (A.A.); (A.D.R.)
| | - Maria Raffaella Petrara
- Oncology and Immunology Section, Department of Surgery, Oncology and Gastroenterology, University of Padova, 35128 Padova, Italy; (M.Z.); (A.C.); (G.B.); (M.R.P.); (A.A.); (A.D.R.)
| | - Aamir Amin
- Oncology and Immunology Section, Department of Surgery, Oncology and Gastroenterology, University of Padova, 35128 Padova, Italy; (M.Z.); (A.C.); (G.B.); (M.R.P.); (A.A.); (A.D.R.)
| | | | - Miguel Godinho Ferreira
- Institute for Research on Cancer and Aging of Nice (IRCAN), UMR7284 U1081 UNS, Université Côte d’Azur, 06107 Nice CEDEX 2, France;
| | - Anita De Rossi
- Oncology and Immunology Section, Department of Surgery, Oncology and Gastroenterology, University of Padova, 35128 Padova, Italy; (M.Z.); (A.C.); (G.B.); (M.R.P.); (A.A.); (A.D.R.)
- Immunology and Diagnostic Molecular Oncology Unit, Veneto Institute of Oncology IOV–IRCCS, 35128 Padova, Italy;
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7
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Ségal-Bendirdjian E, Geli V. Non-canonical Roles of Telomerase: Unraveling the Imbroglio. Front Cell Dev Biol 2019; 7:332. [PMID: 31911897 PMCID: PMC6914764 DOI: 10.3389/fcell.2019.00332] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/27/2019] [Indexed: 12/11/2022] Open
Abstract
Telomerase plays a critical role in stem cell function and tissue regeneration that depends on its ability to elongate telomeres. For nearly two decades, it turned out that TERT regulates a broad spectrum of functions including signal transduction, gene expression regulation, and protection against oxidative damage that are independent of its telomere elongation activity. These conclusions that were mainly obtained in cell lines overexpressing telomerase were further strengthened by in vivo models of ectopic expression of telomerase or models of G1 TERT knockout mice without detectable telomere dysfunction. However, the later models were questioned due to the presence of aberrantly shortened telomere in the germline of the parents TERT+/- that were used to create the G1 TERT -/- mice. The physiological relevance of the functions associated with overexpressed telomerase raised also some concerns due to artifactual situations and localizations and complications to quantify the level of TERT. Another concern with non-canonical functions of TERT was the difficulty to separate a direct TERT-related function from secondary effects. Despite these concerns, more and more evidence accumulates for non-canonical roles of telomerase that are non-obligatory extra-telomeric. Here, we review these non-canonical roles of the TERT subunit of telomerase. Also, we emphasize recent results that link TERT to mitochondria and protection to reactive oxygen species suggesting a protective role of TERT in neurons. Throughout this review, we dissect some controversies regarding the non-canonical functions of telomerase and provide some insights to explain these discrepancies. Finally, we discuss the importance of understanding these alternative functions of telomerase for the development of anticancer strategies.
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Affiliation(s)
- Evelyne Ségal-Bendirdjian
- INSERM UMR-S 1124, Team: Cellular Homeostasis, Cancer and Therapies, INSERM US36, CNRS UMS 2009, BioMedTech Facilities, Université de Paris, Paris, France
| | - Vincent Geli
- Marseille Cancer Research Center, U1068 INSERM, UMR 7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, Equipe labellisée Ligue, Marseille, France
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8
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Cayuela ML, Claes KBM, Ferreira MG, Henriques CM, van Eeden F, Varga M, Vierstraete J, Mione MC. The Zebrafish as an Emerging Model to Study DNA Damage in Aging, Cancer and Other Diseases. Front Cell Dev Biol 2019; 6:178. [PMID: 30687705 PMCID: PMC6335974 DOI: 10.3389/fcell.2018.00178] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 12/22/2018] [Indexed: 12/17/2022] Open
Abstract
Cancer is a disease of the elderly, and old age is its largest risk factor. With age, DNA damage accumulates continuously, increasing the chance of malignant transformation. The zebrafish has emerged as an important vertebrate model to study these processes. Key mechanisms such as DNA damage responses and cellular senescence can be studied in zebrafish throughout its life course. In addition, the zebrafish is becoming an important resource to study telomere biology in aging, regeneration and cancer. Here we review some of the tools and resources that zebrafish researchers have developed and discuss their potential use in the study of DNA damage, cancer and aging related diseases.
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Affiliation(s)
- Maria Luisa Cayuela
- Telomerase, Cancer and Aging Group, Surgery Unit, Instituto Murciano de Investigación Biosanitaria-Arrixaca, Murcia, Spain
| | | | | | - Catarina Martins Henriques
- Department of Oncology and Metabolism, Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | | | - Máté Varga
- Department of Genetics, Eötvös Loránd University, Budapest, Hungary
- MTA-SE Lendület Nephrogenetic Laboratory, Budapest, Hungary
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9
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Jose SS, Tidu F, Burilova P, Kepak T, Bendickova K, Fric J. The Telomerase Complex Directly Controls Hematopoietic Stem Cell Differentiation and Senescence in an Induced Pluripotent Stem Cell Model of Telomeropathy. Front Genet 2018; 9:345. [PMID: 30210531 PMCID: PMC6123533 DOI: 10.3389/fgene.2018.00345] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/09/2018] [Indexed: 01/16/2023] Open
Abstract
Telomeropathies are rare disorders associated with impaired telomere length control mechanisms that frequently result from genetic mutations in the telomerase complex. Dyskeratosis congenita is a congenital progressive telomeropathy in which mutation in the telomerase RNA component (TERC) impairs telomere maintenance leading to accelerated cellular senescence and clinical outcomes resembling premature aging. The most severe clinical feature is perturbed hematopoiesis and bone-marrow failure, but the underlying mechanisms are not fully understood. Here, we developed a model of telomerase function imbalance using shRNA to knockdown TERC expression in human induced pluripotent stem cells (iPSCs). We then promoted in vitro hematopoiesis in these cells to analyze the effects of TERC impairment. Reduced TERC expression impaired hematopoietic stem-cell (HSC) differentiation and increased the expression of cellular senescence markers and production of reactive oxygen species. Interestingly, telomere length was unaffected in shTERC knockdown iPSCs, leading to conclusion that the phenotype is controlled by non-telomeric functions of telomerase. We then assessed the effects of TERC-depletion in THP-1 myeloid cells and again observed reduced hematopoietic and myelopoietic differentiative potential. However, these cells exhibited impaired telomerase activity as verified by accelerated telomere shortening. shTERC-depleted iPSC-derived and THP-1-derived myeloid precursors had lower phagocytic capacity and increased ROS production, indicative of senescence. These findings were confirmed using a BIBR1532 TERT inhibitor, suggesting that these phenotypes are dependent on telomerase function but not directly linked to telomere length. These data provide a better understanding of the molecular processes driving the clinical signs of telomeropathies and identify novel roles of the telomerase complex other than regulating telomere length.
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Affiliation(s)
- Shyam Sushama Jose
- Cellular and Molecular Immunoregulation Group, Center for Translational Medicine, International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czechia.,Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Federico Tidu
- Cellular and Molecular Immunoregulation Group, Center for Translational Medicine, International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czechia.,Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Petra Burilova
- Cellular and Molecular Immunoregulation Group, Center for Translational Medicine, International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czechia.,Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Tomas Kepak
- Pediatric Oncology Translational Research, International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czechia.,Pediatric Hematology and Oncology, The University Hospital Brno, Brno, Czechia
| | - Kamila Bendickova
- Cellular and Molecular Immunoregulation Group, Center for Translational Medicine, International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czechia
| | - Jan Fric
- Cellular and Molecular Immunoregulation Group, Center for Translational Medicine, International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czechia
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10
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Wang J, Zhang MY, Xu SQ, Cheng J, Yu ZJ, Hu XM. Down-regulation of telomerase reverse transcriptase-related anti-apoptotic function in a rat model of acrylamide induced neurobehavioral deficits. Biotech Histochem 2018; 93:512-518. [PMID: 29926741 DOI: 10.1080/10520295.2018.1471523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Although the precise mechanism is unknown, neuron apoptosis is believed to participate in neuropathy caused by acrylamide (ACR). Telomerase reverse transcriptase (TERT) exhibits an anti-apoptotic function, but its contribution to the pathogenesis of ACR neurotoxicity is unclear. We investigated adult male rats that were given 30, 40 and 50 mg/kg ACR three times/week for 4 weeks. We found that ACR treatment caused significant deficits in sensory/motor function as measured by gait score, landing foot spread distance, movement initiation test and tail immersion test. Histological examination showed that the cerebral cortex in all ACR treated animals exhibited fewer neurons and more condensed nuclei than normal cortex. A significant increase in apoptosis was found in the cerebral cortex of rat brains subjected to ACR treatment in a dose-dependent manner. The expression of TERT in the brain was significantly reduced by ACR treatment. The pro-apoptotic cleaved caspase-3 protein level was increased, while the anti-apoptotic Bcl-2 protein level was decreased by 30 - 50 mg/kg ACR. Our findings indicate that TERT and its downstream regulators of neuron apoptosis, including Bcl-2 and cleaved caspase-3, were involved in ACR neurotoxicity.
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Affiliation(s)
- J Wang
- a Department of Pharmacy , College of Medicine, Wuhan University of Science and Technology , Wuhan.,b Hubei Province Key Laboratory of Occupational Hazard Identification and Control , Wuhan University of Science and Technology , Wuhan
| | - M Y Zhang
- a Department of Pharmacy , College of Medicine, Wuhan University of Science and Technology , Wuhan.,b Hubei Province Key Laboratory of Occupational Hazard Identification and Control , Wuhan University of Science and Technology , Wuhan
| | - S Q Xu
- a Department of Pharmacy , College of Medicine, Wuhan University of Science and Technology , Wuhan.,b Hubei Province Key Laboratory of Occupational Hazard Identification and Control , Wuhan University of Science and Technology , Wuhan
| | - J Cheng
- a Department of Pharmacy , College of Medicine, Wuhan University of Science and Technology , Wuhan.,b Hubei Province Key Laboratory of Occupational Hazard Identification and Control , Wuhan University of Science and Technology , Wuhan
| | - Z J Yu
- a Department of Pharmacy , College of Medicine, Wuhan University of Science and Technology , Wuhan.,b Hubei Province Key Laboratory of Occupational Hazard Identification and Control , Wuhan University of Science and Technology , Wuhan
| | - X M Hu
- a Department of Pharmacy , College of Medicine, Wuhan University of Science and Technology , Wuhan.,b Hubei Province Key Laboratory of Occupational Hazard Identification and Control , Wuhan University of Science and Technology , Wuhan.,c College of Pharmacy , Shanghai University of Medicine & Health Sciences , Shanghai , China
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11
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Scahill CM, Digby Z, Sealy IM, White RJ, Wali N, Collins JE, Stemple DL, Busch-Nentwich EM. The age of heterozygous telomerase mutant parents influences the adult phenotype of their offspring irrespective of genotype in zebrafish. Wellcome Open Res 2018; 2:77. [PMID: 29568807 PMCID: PMC5840683 DOI: 10.12688/wellcomeopenres.12530.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2017] [Indexed: 12/03/2022] Open
Abstract
Background: Mutations in proteins involved in telomere maintenance lead to a range of human diseases, including dyskeratosis congenita, idiopathic pulmonary fibrosis and cancer. Telomerase functions to add telomeric repeats back onto the ends of chromosomes, however non-canonical roles of components of telomerase have recently been suggested. Methods: Here we use a zebrafish telomerase mutant which harbours a nonsense mutation in
tert to investigate the adult phenotypes of fish derived from heterozygous parents of different ages. Furthermore we use whole genome sequencing data to estimate average telomere lengths. Results: We show that homozygous offspring from older heterozygotes exhibit signs of body wasting at a younger age than those of younger parents, and that offspring of older heterozygous parents weigh less irrespective of genotype. We also demonstrate that
tert homozygous mutant fish have a male sex bias, and that clutches from older parents also have a male sex bias in the heterozygous and wild-type populations. Telomere length analysis reveals that the telomeres of younger heterozygous parents are shorter than those of older heterozygous parents. Conclusions: These data indicate that the phenotypes observed in offspring from older parents cannot be explained by telomere length. Instead we propose that Tert functions outside of telomere length maintenance in an age-dependent manner to influence the adult phenotypes of the next generation.
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Affiliation(s)
| | - Zsofia Digby
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK.,Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Ian M Sealy
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Richard J White
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Neha Wali
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - John E Collins
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Derek L Stemple
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Elisabeth M Busch-Nentwich
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK.,Department of Medicine, University of Cambridge, Cambridge, UK
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Carneiro MC, de Castro IP, Ferreira MG. Telomeres in aging and disease: lessons from zebrafish. Dis Model Mech 2017; 9:737-48. [PMID: 27482813 PMCID: PMC4958310 DOI: 10.1242/dmm.025130] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Age is the highest risk factor for some of the most prevalent human diseases, including cancer. Telomere shortening is thought to play a central role in the aging process in humans. The link between telomeres and aging is highlighted by the fact that genetic diseases causing telomerase deficiency are associated with premature aging and increased risk of cancer. For the last two decades, this link has been mostly investigated using mice that have long telomeres. However, zebrafish has recently emerged as a powerful and complementary model system to study telomere biology. Zebrafish possess human-like short telomeres that progressively decline with age, reaching lengths in old age that are observed when telomerase is mutated. The extensive characterization of its well-conserved molecular and cellular physiology makes this vertebrate an excellent model to unravel the underlying relationship between telomere shortening, tissue regeneration, aging and disease. In this Review, we explore the advantages of using zebrafish in telomere research and discuss the primary discoveries made in this model that have contributed to expanding our knowledge of how telomere attrition contributes to cellular senescence, organ dysfunction and disease. Summary: In this Review, the authors explore the advantages of using zebrafish in telomere research and discuss the primary discoveries made in this model that have contributed to expanding our knowledge of how telomere attrition contributes to cellular senescence, organ dysfunction and disease.
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Scahill CM, Digby Z, Sealy IM, White RJ, Collins JE, Busch-Nentwich EM. The age of heterozygous telomerase mutant parents influences the adult phenotype of their offspring irrespective of genotype in zebrafish. Wellcome Open Res 2017. [DOI: 10.12688/wellcomeopenres.12530.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Mutations in proteins involved in telomere maintenance lead to a range of human diseases, including dyskeratosis congenita, idiopathic pulmonary fibrosis and cancer. Telomerase functions to add telomeric repeats back onto the ends of chromosomes, however non-canonical roles of components of telomerase have recently been suggested.Methods: Here we use a zebrafish telomerase mutant which harbours a nonsense mutation intertto investigate the adult phenotypes of fish derived from heterozygous parents of different ages. Furthermore we use whole genome sequencing data to estimate average telomere lengths.Results: We show that homozygous offspring from older heterozygotes exhibit signs of body wasting at a younger age than those of younger parents, and that offspring of older heterozygous parents weigh less irrespective of genotype. We also demonstrate thatterthomozygous mutant fish have a male sex bias, and that clutches from older parents also have a male sex bias in the heterozygous and wild-type populations. Telomere length analysis reveals that the telomeres of younger heterozygous parents are shorter than those of older heterozygous parents.Conclusions: These data indicate that the phenotypes observed in offspring from older parents cannot be explained by telomere length. Instead we propose that Tert functions outside of telomere length maintenance in an age-dependent manner to influence the adult phenotypes of the next generation.
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14
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Lai AG, Pouchkina-Stantcheva N, Di Donfrancesco A, Kildisiute G, Sahu S, Aboobaker AA. The protein subunit of telomerase displays patterns of dynamic evolution and conservation across different metazoan taxa. BMC Evol Biol 2017; 17:107. [PMID: 28441946 PMCID: PMC5405514 DOI: 10.1186/s12862-017-0949-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 04/04/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Most animals employ telomerase, which consists of a catalytic subunit known as the telomerase reverse transcriptase (TERT) and an RNA template, to maintain telomere ends. Given the importance of TERT and telomere biology in core metazoan life history traits, like ageing and the control of somatic cell proliferation, we hypothesised that TERT would have patterns of sequence and regulatory evolution reflecting the diverse life histories across the Animal Kingdom. RESULTS We performed a complete investigation of the evolutionary history of TERT across animals. We show that although TERT is almost ubiquitous across Metazoa, it has undergone substantial sequence evolution within canonical motifs. Beyond the known canonical motifs, we also identify and compare regions that are highly variable between lineages, but show conservation within phyla. Recent data have highlighted the importance of alternative splice forms of TERT in non-canonical functions and although animals may share some conserved introns, we find that the selection of exons for alternative splicing appears to be highly variable, and regulation by alternative splicing appears to be a very dynamic feature of TERT evolution. We show that even within a closely related group of triclad flatworms, where alternative splicing of TERT was previously correlated with reproductive strategy, we observe highly diverse splicing patterns. CONCLUSIONS Our work establishes that the evolutionary history and structural evolution of TERT involves previously unappreciated levels of change and the emergence of lineage specific motifs. The sequence conservation we describe within phyla suggests that these new motifs likely serve essential biological functions of TERT, which along with changes in splicing, underpin diverse functions of TERT important for animal life histories.
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Affiliation(s)
- Alvina G Lai
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
| | | | | | - Gerda Kildisiute
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Sounak Sahu
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - A Aziz Aboobaker
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
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15
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Im E, Yoon JB, Lee HW, Chung KC. Human Telomerase Reverse Transcriptase (hTERT) Positively Regulates 26S Proteasome Activity. J Cell Physiol 2017; 232:2083-2093. [PMID: 27648923 DOI: 10.1002/jcp.25607] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/19/2016] [Indexed: 02/02/2023]
Abstract
Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase, an RNA-dependent DNA polymerase that elongates telomeric DNA. hTERT displays several extra-telomeric functions that are independent of its telomere-regulatory function, including tumor progression, and neuronal cell death regulation. In this study, we evaluated these additional hTERT non-telomeric functions. We determined that hTERT interacts with several 19S and 20S proteasome subunits. The 19S regulatory particle and 20S core particle are part of 26S proteasome complex, which plays a central role in ubiquitin-dependent proteolysis. In addition, hTERT positively regulated 26S proteasome activity independent of its enzymatic activity. Moreover, hTERT enhanced subunit interactions, which may underlie hTERT's ability of hTERT to stimulate the 26S proteasome. Furthermore, hTERT displayed cytoprotective effect against ER stress via the activation of 26S proteasome in acute myeloid leukemia cells. Our data suggest that hTERT acts as a novel chaperone to promote 26S proteasome assembly and maintenance. J. Cell. Physiol. 232: 2083-2093, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Eunju Im
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Jong Bok Yoon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Kwang Chul Chung
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
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16
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Sasaki T, Lian S, Khan A, Llop JR, Samuelson AV, Chen W, Klionsky DJ, Kishi S. Autolysosome biogenesis and developmental senescence are regulated by both Spns1 and v-ATPase. Autophagy 2016; 13:386-403. [PMID: 27875093 DOI: 10.1080/15548627.2016.1256934] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Spns1 (Spinster homolog 1 [Drosophila]) in vertebrates, as well as Spin (Spinster) in Drosophila, is a hypothetical lysosomal H+-carbohydrate transporter, which functions at a late stage of macroautophagy (hereafter autophagy). The Spin/Spns1 defect induces aberrant autolysosome formation that leads to developmental senescence in the embryonic stage and premature aging symptoms in adulthood. However, the molecular mechanism by which loss of Spin/Spns1 leads to the specific pathogenesis remains to be elucidated. Using chemical, genetic and CRISPR/Cas9-mediated genome-editing approaches in zebrafish, we investigated and determined a mechanism that suppresses embryonic senescence as well as autolysosomal impairment mediated by Spns1 deficiency. Unexpectedly, we found that a concurrent disruption of the vacuolar-type H+-ATPase (v-ATPase) subunit gene, atp6v0ca (ATPase, H+ transporting, lysosomal, V0 subunit ca) led to suppression of the senescence induced by the Spns1 defect, whereas the sole loss of Atp6v0ca led to senescent embryos similar to the single spns1 mutation. Moreover, we discovered that the combined stable defect seen in the presence of both the spns1 and atp6v0ca mutant genes still subsequently induced premature autophagosome-lysosome fusion marked by insufficient acidity, while extending developmental life span, compared with the solely mutated spns1 defect. Our data suggest that Spns1 and the v-ATPase orchestrate proper autolysosomal biogenesis with optimal acidification that is critically linked to developmental senescence and survival.
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Affiliation(s)
- Tomoyuki Sasaki
- a Department of Metabolism & Aging , The Scripps Research Institute , Jupiter , FL , USA
| | - Shanshan Lian
- a Department of Metabolism & Aging , The Scripps Research Institute , Jupiter , FL , USA
| | - Alam Khan
- a Department of Metabolism & Aging , The Scripps Research Institute , Jupiter , FL , USA.,b Department of Pharmacy , University of Rajshahi , Rajshahi , Bangladesh
| | - Jesse R Llop
- c Department of Biomedical Genetics , University of Rochester Medical Center , Rochester , NY , USA
| | - Andrew V Samuelson
- c Department of Biomedical Genetics , University of Rochester Medical Center , Rochester , NY , USA
| | - Wenbiao Chen
- d Department of Molecular Physiology and Biophysics , Vanderbilt University School of Medicine , Nashville , TN , USA
| | - Daniel J Klionsky
- e Life Sciences Institute, Department of Molecular, Cellular, and Developmental Biology , University of Michigan , Ann Arbor , MI , USA
| | - Shuji Kishi
- a Department of Metabolism & Aging , The Scripps Research Institute , Jupiter , FL , USA
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17
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Abstract
Telomerase activity is responsible for the maintenance of chromosome end structures (telomeres) and cancer cell immortality in most human malignancies, making telomerase an attractive therapeutic target. The rationale for targeting components of the telomerase holoenzyme has been strengthened by accumulating evidence indicating that these molecules have extra-telomeric functions in tumour cell survival and proliferation. This Review discusses current knowledge of the biogenesis, structure and multiple functions of telomerase-associated molecules intertwined with recent advances in drug discovery approaches. We also describe the fertile ground available for the pursuit of next-generation small-molecule inhibitors of telomerase.
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Affiliation(s)
- Greg M Arndt
- Australian Cancer Research Foundation (ACRF) Drug Discovery Centre for Childhood Cancer, Children's Cancer Institute Australia, Lowy Cancer Research Centre, University of New South Wales, Randwick, New South Wales 2031, Australia
| | - Karen L MacKenzie
- Personalised Medicine Program, Children's Cancer Institute Australia, Lowy Cancer Research Centre, University of New South Wales, Randwick, New South Wales 2031, Australia
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18
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Short Telomeres in Key Tissues Initiate Local and Systemic Aging in Zebrafish. PLoS Genet 2016; 12:e1005798. [PMID: 26789415 PMCID: PMC4720274 DOI: 10.1371/journal.pgen.1005798] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 12/20/2015] [Indexed: 12/30/2022] Open
Abstract
Telomeres shorten with each cell division and telomere dysfunction is a recognized hallmark of aging. Tissue proliferation is expected to dictate the rate at which telomeres shorten. We set out to test whether proliferative tissues age faster than non-proliferative due to telomere shortening during zebrafish aging. We performed a prospective study linking telomere length to tissue pathology and disease. Contrary to expectations, we show that telomeres shorten to critical lengths only in specific tissues and independently of their proliferation rate. Short telomeres accumulate in the gut but not in other highly proliferative tissues such as the blood and gonads. Notably, the muscle, a low proliferative tissue, accumulates short telomeres and DNA damage at the same rate as the gut. Together, our work shows that telomere shortening and DNA damage in key tissues triggers not only local dysfunction but also anticipates the onset of age-associated diseases in other tissues, including cancer. Why, and how, organisms age and ultimately die is a key question of modern biology. Telomeres are considered molecular timekeepers determining cellular lifespans. Within an organism, tissue proliferation is expected to dictate the rate at which telomeres shorten. Using zebrafish, an organism with human-like telomeres, we set out to test whether, in natural aging, proliferative tissues age faster than non-proliferative in a telomere-dependent manner. We found that telomeres shorten with age to a level where they trigger telomere associated DNA damage and culminate in tissue dysfunction, independently of high or low tissue proliferation rates. Specifically, short telomeres accumulate in the gut, a highly proliferative tissue, and in the muscle, a low proliferative tissue, working as direct predictors of cellular damage prior to onset of intestinal inflammation and myocyte degeneration. Based on our data, we propose a model where telomere shortening in these key tissues is sufficient to trigger damage in others and precedes the onset of organism age-associated diseases, namely cancer. Thus, tissue-specific telomere length is limiting for local and systemic physiological integrity, leading to tissue degeneration and disease in aging.
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19
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A non-canonical function of telomerase RNA in the regulation of developmental myelopoiesis in zebrafish. Nat Commun 2015; 5:3228. [PMID: 24496182 DOI: 10.1038/ncomms4228] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 01/09/2014] [Indexed: 02/04/2023] Open
Abstract
Dyskeratosis congenita (DC) is an inherited disorder with mutations affecting telomerase or telomeric proteins. DC patients usually die of bone marrow failure. Here we show that genetic depletion of the telomerase RNA component (TR) in the zebrafish results in impaired myelopoiesis, despite normal development of haematopoietic stem cells (HSCs). The neutropenia caused by TR depletion is independent of telomere length and telomerase activity. Genetic analysis shows that TR modulates the myeloid-erythroid fate decision by controlling the levels of the master myeloid and erythroid transcription factors spi1 and gata1, respectively. The alteration in spi1 and gata1 levels occurs through stimulation of gcsf and mcsf. Our model of TR deficiency in the zebrafish illuminates the non-canonical roles of TR, and could establish therapeutic targets for DC.
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20
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Bednarek D, González-Rosa JM, Guzmán-Martínez G, Gutiérrez-Gutiérrez Ó, Aguado T, Sánchez-Ferrer C, Marques IJ, Galardi-Castilla M, de Diego I, Gómez MJ, Cortés A, Zapata A, Jiménez-Borreguero LJ, Mercader N, Flores I. Telomerase Is Essential for Zebrafish Heart Regeneration. Cell Rep 2015; 12:1691-703. [PMID: 26321646 PMCID: PMC4589159 DOI: 10.1016/j.celrep.2015.07.064] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 05/27/2015] [Accepted: 07/29/2015] [Indexed: 11/05/2022] Open
Abstract
After myocardial infarction in humans, lost cardiomyocytes are replaced by an irreversible fibrotic scar. In contrast, zebrafish hearts efficiently regenerate after injury. Complete regeneration of the zebrafish heart is driven by the strong proliferation response of its cardiomyocytes to injury. Here we show that, after cardiac injury in zebrafish, telomerase becomes hyperactivated, and telomeres elongate transiently, preceding a peak of cardiomyocyte proliferation and full organ recovery. Using a telomerase-mutant zebrafish model, we found that telomerase loss drastically decreases cardiomyocyte proliferation and fibrotic tissue regression after cryoinjury and that cardiac function does not recover. The impaired cardiomyocyte proliferation response is accompanied by the absence of cardiomyocytes with long telomeres and an increased proportion of cardiomyocytes showing DNA damage and senescence characteristics. These findings demonstrate the importance of telomerase function in heart regeneration and highlight the potential of telomerase therapy as a means of stimulating cell proliferation upon myocardial infarction.
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Affiliation(s)
- Dorota Bednarek
- Regeneration and Aging Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Juan Manuel González-Rosa
- Development of the Epicardium and Its Role during Regeneration Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Gabriela Guzmán-Martínez
- Cardiovascular Imaging in Humans, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Óscar Gutiérrez-Gutiérrez
- Regeneration and Aging Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Tania Aguado
- Regeneration and Aging Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Carlota Sánchez-Ferrer
- Regeneration and Aging Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Inês João Marques
- Development of the Epicardium and Its Role during Regeneration Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - María Galardi-Castilla
- Development of the Epicardium and Its Role during Regeneration Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Irene de Diego
- Regeneration and Aging Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Manuel José Gómez
- Bioinformatic Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Alfonso Cortés
- Electron Microscopy Center, Complutense University, Madrid 28040, Spain
| | - Agustín Zapata
- Electron Microscopy Center, Complutense University, Madrid 28040, Spain
| | - Luis Jesús Jiménez-Borreguero
- Cardiovascular Imaging in Humans, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Nadia Mercader
- Development of the Epicardium and Its Role during Regeneration Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain.
| | - Ignacio Flores
- Regeneration and Aging Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC-ISCIII), Melchor Fernández Almagro 3, 28029 Madrid, Spain.
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21
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Sasaki T, Lian S, Qi J, Bayliss PE, Carr CE, Johnson JL, Guha S, Kobler P, Catz SD, Gill M, Jia K, Klionsky DJ, Kishi S. Aberrant autolysosomal regulation is linked to the induction of embryonic senescence: differential roles of Beclin 1 and p53 in vertebrate Spns1 deficiency. PLoS Genet 2014; 10:e1004409. [PMID: 24967584 PMCID: PMC4072523 DOI: 10.1371/journal.pgen.1004409] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 04/16/2014] [Indexed: 12/04/2022] Open
Abstract
Spinster (Spin) in Drosophila or Spinster homolog 1 (Spns1) in vertebrates is a putative lysosomal H+-carbohydrate transporter, which functions at a late stage of autophagy. The Spin/Spns1 defect induces aberrant autolysosome formation that leads to embryonic senescence and accelerated aging symptoms, but little is known about the mechanisms leading to the pathogenesis in vivo. Beclin 1 and p53 are two pivotal tumor suppressors that are critically involved in the autophagic process and its regulation. Using zebrafish as a genetic model, we show that Beclin 1 suppression ameliorates Spns1 loss-mediated senescence as well as autophagic impairment, whereas unexpectedly p53 deficit exacerbates both of these characteristics. We demonstrate that ‘basal p53’ activity plays a certain protective role(s) against the Spns1 defect-induced senescence via suppressing autophagy, lysosomal biogenesis, and subsequent autolysosomal formation and maturation, and that p53 loss can counteract the effect of Beclin 1 suppression to rescue the Spns1 defect. By contrast, in response to DNA damage, ‘activated p53’ showed an apparent enhancement of the Spns1-deficient phenotype, by inducing both autophagy and apoptosis. Moreover, we found that a chemical and genetic blockage of lysosomal acidification and biogenesis mediated by the vacuolar-type H+-ATPase, as well as of subsequent autophagosome-lysosome fusion, prevents the appearance of the hallmarks caused by the Spns1 deficiency, irrespective of the basal p53 state. Thus, these results provide evidence that Spns1 operates during autophagy and senescence differentially with Beclin 1 and p53. Spinster homolog 1 (Spns1) in vertebrates, as well as Spinster (Spin) in Drosophila, is a hypothetical lysosomal H+-carbohydrate transporter, which functions at a late stage of autophagy. The Spin/Spns1 defect induces aberrant autolysosome formation that leads to embryonic senescence and accelerated aging symptoms, while the molecular mechanisms of the pathogenesis are unknown in vivo. Using zebrafish, we show that Beclin 1 suppression ameliorates Spns1 loss-mediated senescence as well as autolysosomal impairment, whereas p53 deficit unexpectedly exacerbates these characteristics. We demonstrate that basal p53 activity has a certain protective role(s) against the Spns1 defect via suppressing autophagosome-lysosome fusion, while p53 activated by ultraviolet radiation amplifies the Spns1 deficit. In addition, we found that excessive lysosomal biogenesis and prolonged suboptimal acidification, modulated by v-ATPase, could be the primary reason for the appearance on the hallmarks of Spns1 deficiency. Our findings thus suggest that Spns1 is critically involved in lysosomal acidification and trafficking during autophagy, and differentially acts in a pathway with Beclin 1 and p53 in the regulation of senescence.
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Affiliation(s)
- Tomoyuki Sasaki
- Department of Metabolism & Aging, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Shanshan Lian
- Department of Metabolism & Aging, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Jie Qi
- Department of Metabolism & Aging, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Peter E. Bayliss
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Christopher E. Carr
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Jennifer L. Johnson
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Sujay Guha
- Department of Metabolism & Aging, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Patrick Kobler
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida, United States of America
| | - Sergio D. Catz
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Matthew Gill
- Department of Metabolism & Aging, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida, United States of America
| | - Daniel J. Klionsky
- Life Sciences Institute, Department of Molecular, Cellular, and Developmental Biology, Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Shuji Kishi
- Department of Metabolism & Aging, The Scripps Research Institute, Jupiter, Florida, United States of America
- * E-mail:
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López de Abechuco E, Bilbao E, Soto M, Díez G. Molecular cloning and measurement of telomerase reverse transcriptase (TERT) transcription patterns in tissues of European hake (Merluccius merluccius) and Atlantic cod (Gadus morhua) during aging. Gene 2014; 541:8-18. [PMID: 24607378 DOI: 10.1016/j.gene.2014.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/28/2014] [Accepted: 03/06/2014] [Indexed: 01/01/2023]
Abstract
Telomerase is a reverse transcriptase ribonucleoprotein that maintains the ends of linear chromosomes. This enzyme plays a major role in cell processes like proliferation, differentiation and tumorigenesis, being associated with aging and survival of species. In this study, the gene coding for TERT (Telomerase Reverse Transcriptase) of two commercial fish species, European hake (Merluccius merluccius) and Atlantic cod (Gadus morhua), has been partially cloned. A fragment of 1581bp (hake) and 633bp (cod) showed high homology (identity 74%, query cover 99%, E-value=0) with known Perciformes TERT sequences. TERT transcription patterns were assessed by qRT-PCR in different tissues of hake (brain, ovary, testis, muscle, skin, gills, liver and kidney) and cod (brain, muscle and skin) of different sizes/ages in order to understand its role in the physiological aging of teleosts. TERT was found to be ubiquitously transcribed in all tissues and size/age groups studied in both species. Significantly higher relative transcription levels (p<0.05) were found with increasing size/age of M. merluccius in the kidney, muscle, skin and gonad, the latter exhibiting particularly high relative transcription levels. Male hakes showed higher TERT relative transcription levels in the brain, gonad and liver than females, although these differences were not statistically significant (p<0.05). In G. morhua, higher TERT relative transcription levels were recorded in the muscle and brain of fry and juvenile individuals. Therefore, TERT relative transcription pattern exhibited a higher telomerase demand in early developmental stages and also in mature stages, suggesting tissue renewal or regeneration processes as a conserved mechanism for maintaining long-term cell proliferation capacity and preventing senescence. Thus, it can be concluded that TERT relative transcription level was species and tissue specific and changed with the age of fishes.
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Affiliation(s)
- E López de Abechuco
- AZTI-Tecnalia, Marine Research Division, Txatxarramendi Ugartea z/g, 48395 Sukarrieta, Bizkaia, Spain
| | - E Bilbao
- Department of Zoology and Animal Cell Biology, Research Centre for Experimental Marine Biology and Biotechnology (PIE-UPV/EHU), University of the Basque Country, Areatza z/g, Plentzia, Bizkaia, Spain
| | - M Soto
- Department of Zoology and Animal Cell Biology, Research Centre for Experimental Marine Biology and Biotechnology (PIE-UPV/EHU), University of the Basque Country, Areatza z/g, Plentzia, Bizkaia, Spain
| | - G Díez
- AZTI-Tecnalia, Marine Research Division, Txatxarramendi Ugartea z/g, 48395 Sukarrieta, Bizkaia, Spain
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23
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Kishi S. Using zebrafish models to explore genetic and epigenetic impacts on evolutionary developmental origins of aging. Transl Res 2014; 163:123-35. [PMID: 24239812 PMCID: PMC3969878 DOI: 10.1016/j.trsl.2013.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 10/20/2013] [Accepted: 10/21/2013] [Indexed: 01/10/2023]
Abstract
Can we reset, reprogram, rejuvenate, or reverse the organismal aging process? Certain genetic manipulations could at least reset and reprogram epigenetic dynamics beyond phenotypic plasticity and elasticity in cells, which can be manipulated further into organisms. However, in a whole complex aging organism, how can we rejuvenate intrinsic resources and infrastructures in an intact and noninvasive manner? The incidence of diseases increases exponentially with age, accompanied by progressive deteriorations of physiological functions in organisms. Aging-associated diseases are sporadic but essentially inevitable complications arising from senescence. Senescence is often considered the antithesis of early development, but yet there may be factors and mechanisms in common between these 2 phenomena to rejuvenate over the dynamic process of aging. The association between early development and late-onset disease with advancing age is thought to come from a consequence of developmental plasticity, the phenomenon by which one genotype can give rise to a range of physiologically and/or morphologically adaptive states based on diverse epigenotypes in response to intrinsic or extrinsic environmental cues and genetic perturbations. We hypothesized that the future aging process can be predictive based on adaptivity during the early developmental period. Modulating the thresholds and windows of plasticity and its robustness by molecular genetic and chemical epigenetic approaches, we have successfully conducted experiments to isolate zebrafish mutants expressing apparently altered senescence phenotypes during their embryonic and/or larval stages ("embryonic/larval senescence"). Subsequently, at least some of these mutant animals were found to show a shortened life span, whereas others would be expected to live longer into adulthood. We anticipate that previously uncharacterized developmental genes may mediate the aging process and play a pivotal role in senescence. On the other hand, unexpected senescence-related genes might also be involved in the early developmental process and its regulation. The ease of manipulation using the zebrafish system allows us to conduct an exhaustive exploration of novel genes, genotypes, and epigenotypes that can be linked to the senescence phenotype, which facilitates searching for the evolutionary and developmental origins of aging in vertebrates.
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Affiliation(s)
- Shuji Kishi
- Department of Metabolism & Aging, The Scripps Research Institute, Scripps Florida, Jupiter, Fla.
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24
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Batista LFZ. Telomere biology in stem cells and reprogramming. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 125:67-88. [PMID: 24993698 DOI: 10.1016/b978-0-12-397898-1.00003-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Telomerase expression in humans is restricted to different populations of stem and progenitor cells, being silenced in most somatic tissues. Efficient telomere homeostasis is essential for embryonic and adult stem cell function and therefore essential for tissue homeostasis throughout organismal life. Accordingly, the mutations in telomerase culminate in reduced stem cell function both in vivo and in vitro and have been associated with tissue dysfunction in human patients. Despite the importance of telomerase for stem cell biology, the mechanisms behind telomerase regulation during development are still poorly understood, mostly due to difficulties in acquiring and maintaining pluripotent stem cell populations in culture. In this chapter, we will analyze recent developments in this field, including the importance of efficient telomere homeostasis in different stem cell types and the role of telomerase in different techniques used for cellular reprogramming.
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Affiliation(s)
- Luis F Z Batista
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA; Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
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25
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Gopalakrishnan S, Cheung NK, Yip BW, Au DW. Medaka fish exhibits longevity gender gap, a natural drop in estrogen and telomere shortening during aging: a unique model for studying sex-dependent longevity. Front Zool 2013; 10:78. [PMID: 24364913 PMCID: PMC3878272 DOI: 10.1186/1742-9994-10-78] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Accepted: 12/17/2013] [Indexed: 01/07/2023] Open
Abstract
Introduction Females having a longer telomere and lifespan than males have been documented in many animals. Such linkage however has never been reported in fish. Progressive shortening of telomere length is an important aging mechanism. Mounting in vitro evidence has shown that telomere shortening beyond a critical length triggered replicative senescence or cell death. Estrogen has been postulated as a key factor contributing to maintenance of telomere and sex-dependent longevity in animals. This postulation remains unproven due to the lack of a suitable animal system for testing. Here, we introduce a teleost model, the Japanese medaka Oryzias latipes, which shows promise for research into the molecular mechanism(s) controlling sex difference in aging. Results Using the medaka, we demonstrate for the first time in teleost that (i) sex differences (female > male) in telomere length and longevity also exist in fish, and (ii) a natural, ‘menopause’-like decline of plasma estrogen was evident in females during aging. Estrogen levels significantly correlated with telomerase activity as well as telomere length in female organs (not in males), suggesting estrogen could modulate telomere length via telomerase activation in a sex -specific manner. A hypothetical in vivo ‘critical’ terminal restriction fragment (TRF, representing telomere) length of approximately 4 kb was deduced in medaka liver for prediction of organismal mortality, which is highly comparable with that for human cells. An age conversion model was also established to enable age translation between medaka (in months) and human (in years). These novel tools are useful for future research on comparative biology of aging using medaka. Conclusion The striking similarity in estrogen profile between aging female O. latipes and women enables studying the influence of “postmenopausal” decline of estrogen on telomere and longevity without the need of invasive ovariectomy. Medaka fish is advantageous for studying the direct effect of increased estrogen on telomere length and longevity without the breast cancer complications reported in rodents. The findings strongly support the notion that O. latipes is a unique non-mammalian model for validation of estrogenic influence on telomere and longevity in vertebrates. This laboratory model fish is of potential significance for deciphering the ostensibly conserved mechanism(s) of sex-associated longevity in vertebrates.
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Affiliation(s)
| | | | | | - Doris Wt Au
- State Key Laboratory in Marine Pollution, Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR.
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26
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The roles of telomerase in the generation of polyploidy during neoplastic cell growth. Neoplasia 2013; 15:156-68. [PMID: 23441130 DOI: 10.1593/neo.121398] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 11/30/2012] [Accepted: 12/03/2012] [Indexed: 01/20/2023] Open
Abstract
Polyploidy contributes to extensive intratumor genomic heterogeneity that characterizes advanced malignancies and is thought to limit the efficiency of current cancer therapies. It has been shown that telomere deprotection in p53-deficient mouse embryonic fibroblasts leads to high rates of polyploidization. We now show that tumor genome evolution through whole-genome duplication occurs in ∼15% of the karyotyped human neoplasms and correlates with disease progression. In a panel of human cancer and transformed cell lines representing the two known types of genomic instability (chromosomal and microsatellite), as well as the two known pathways of telomere maintenance in cancer (telomerase activity and alternative lengthening of telomeres), telomere dysfunction-driven polyploidization occurred independently of the mutational status of p53. Depending on the preexisting context of telomere maintenance, telomerase activity and its major components, human telomerase reverse transcriptase (hTERT) and human telomerase RNA component (hTERC), exert both reverse transcriptase-related (canonical) and noncanonical functions to affect tumor genome evolution through suppression or induction of polyploidization. These new findings provide a more complete mechanistic understanding of cancer progression that may, in the future, lead to novel therapeutic interventions.
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27
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Anchelin M, Alcaraz-Pérez F, Martínez CM, Bernabé-García M, Mulero V, Cayuela ML. Premature aging in telomerase-deficient zebrafish. Dis Model Mech 2013; 6:1101-12. [PMID: 23744274 PMCID: PMC3759330 DOI: 10.1242/dmm.011635] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The study of telomere biology is crucial to the understanding of aging and cancer. In the pursuit of greater knowledge in the field of human telomere biology, the mouse has been used extensively as a model. However, there are fundamental differences between mouse and human cells. Therefore, additional models are required. In light of this, we have characterized telomerase-deficient zebrafish (Danio rerio) as the second vertebrate model for human telomerase-driven diseases. We found that telomerase-deficient zebrafish show p53-dependent premature aging and reduced lifespan in the first generation, as occurs in humans but not in mice, probably reflecting the similar telomere length in fish and humans. Among these aging symptoms, spinal curvature, liver and retina degeneration, and infertility were the most remarkable. Although the second-generation embryos died in early developmental stages, restoration of telomerase activity rescued telomere length and survival, indicating that telomerase dosage is crucial. Importantly, this model also reproduces the disease anticipation observed in humans with dyskeratosis congenita (DC). Thus, telomerase haploinsufficiency leads to anticipation phenomenon in longevity, which is related to telomere shortening and, specifically, with the proportion of short telomeres. Furthermore, p53 was induced by telomere attrition, leading to growth arrest and apoptosis. Importantly, genetic inhibition of p53 rescued the adverse effects of telomere loss, indicating that the molecular mechanisms induced by telomere shortening are conserved from fish to mammals. The partial rescue of telomere length and longevity by restoration of telomerase activity, together with the feasibility of the zebrafish for high-throughput chemical screening, both point to the usefulness of this model for the discovery of new drugs able to reactivate telomerase in individuals with DC.
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Affiliation(s)
- Monique Anchelin
- Telomerase, Aging and Cancer Group, Research Unit, Department of Surgery, CIBERehd, University Hospital "Virgen de la Arrixaca", Murcia, Spain
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28
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Wang X, Singh S, Jung HY, Yang G, Jun S, Sastry KJ, Park JI. HIV-1 Vpr protein inhibits telomerase activity via the EDD-DDB1-VPRBP E3 ligase complex. J Biol Chem 2013; 288:15474-80. [PMID: 23612978 PMCID: PMC3668709 DOI: 10.1074/jbc.m112.416735] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 04/22/2013] [Indexed: 11/06/2022] Open
Abstract
Viral pathogens utilize host cell machinery for their benefits. Herein, we identify that HIV-1 Vpr (viral protein R) negatively modulates telomerase activity. Telomerase enables stem and cancer cells to evade cell senescence by adding telomeric sequences to the ends of chromosomes. We found that Vpr inhibited telomerase activity by down-regulating TERT protein, a catalytic subunit of telomerase. As a molecular adaptor, Vpr enhanced the interaction between TERT and the VPRBP substrate receptor of the DYRK2-associated EDD-DDB1-VPRBP E3 ligase complex, resulting in increased ubiquitination of TERT. In contrast, the Vpr mutant identified in HIV-1-infected long-term nonprogressors failed to promote TERT destabilization. Our results suggest that Vpr inhibits telomerase activity by hijacking the host E3 ligase complex, and we propose the novel molecular mechanism of telomerase deregulation in possibly HIV-1 pathogenesis.
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Affiliation(s)
- Xin Wang
- From the Departments of Experimental Radiation Oncology and
| | | | - Hae-Yun Jung
- From the Departments of Experimental Radiation Oncology and
| | | | - Sohee Jun
- From the Departments of Experimental Radiation Oncology and
| | | | - Jae-Il Park
- From the Departments of Experimental Radiation Oncology and
- the Program in Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and
- the Graduate School of Biomedical Sciences at Houston, The University of Texas Health Science Center and MD Anderson Cancer Center, Houston, Texas 77030
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29
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Sasaki T, Kishi S. Molecular and chemical genetic approaches to developmental origins of aging and disease in zebrafish. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1362-70. [PMID: 23660559 DOI: 10.1016/j.bbadis.2013.04.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/26/2013] [Accepted: 04/29/2013] [Indexed: 12/13/2022]
Abstract
The incidence of diseases increases rapidly with age, accompanied by progressive deteriorations of physiological functions in organisms. Aging-associated diseases are sporadic but mostly inevitable complications arising from senescence. Senescence is often considered the antithesis of early development, but yet there may be factors and mechanisms in common between these two phenomena over the dynamic process of aging. The association between early development and late-onset disease with advancing age is thought to come from a consequence of developmental plasticity, the phenomenon by which one genotype can give rise to a range of physiologically and/or morphologically adaptive states in response to different environmental or genetic perturbations. On the one hand, we hypothesized that the future aging process can be predictive based on adaptivity during the early developmental period. Modulating the thresholds of adaptive plasticity by chemical genetic approaches, we have been investigating whether any relationship exists between the regulatory mechanisms that function in early development and in senescence using the zebrafish (Danio rerio), a small freshwater fish and a useful model animal for genetic studies. We have successfully conducted experiments to isolate zebrafish mutants expressing apparently altered senescence phenotypes during embryogenesis ("embryonic senescence"), subsequently showing shortened lifespan in adulthoods. We anticipate that previously uncharacterized developmental genes may mediate the aging process and play a pivotal role in senescence. On the other hand, unexpected senescence-related genes might also be involved in the early developmental process and regulation. The ease of manipulation using the zebrafish system allows us to conduct an exhaustive exploration of novel genes and small molecular compounds that can be linked to the senescence phenotype, and thereby facilitates searching for the evolutionary and developmental origins of aging in vertebrates. This article is part of a Special Issue entitled: Animal Models of Disease.
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Affiliation(s)
- Tomoyuki Sasaki
- Department of Metabolism & Aging, The Scripps Research Institute, USA
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30
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Jung HY, Wang X, Jun S, Park JI. Dyrk2-associated EDD-DDB1-VprBP E3 ligase inhibits telomerase by TERT degradation. J Biol Chem 2013; 288:7252-62. [PMID: 23362280 PMCID: PMC3591633 DOI: 10.1074/jbc.m112.416792] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 01/09/2013] [Indexed: 11/06/2022] Open
Abstract
Telomerase maintains the telomere, a specialized chromosomal end structure that is essential for genomic stability and cell immortalization. Telomerase is not active in most somatic cells, but its reactivation is one of the hallmarks of cancer. In this study, we found that dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 2 (Dyrk2) negatively regulates telomerase activity. Dyrk2 phosphorylates TERT protein, a catalytic subunit of telomerase. Phosphorylated TERT is then associated with the EDD-DDB1-VprBP E3 ligase complex for subsequent ubiquitin-mediated TERT protein degradation. During the cell cycle, Dyrk2 interacts with TERT at the G2/M phase and induces degradation. In contrast, depletion of endogenous Dyrk2 disrupts the cell cycle-dependent regulation of TERT and elicits the constitutive activation of telomerase. Similarly, a Dyrk2 nonsense mutation identified in breast cancer compromises ubiquitination-mediated TERT protein degradation. Our findings suggest the novel molecular mechanism of kinase-associated telomerase regulation.
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Affiliation(s)
- Hae-Yun Jung
- From the Department of Experimental Radiation Oncology and
| | - Xin Wang
- From the Department of Experimental Radiation Oncology and
| | - Sohee Jun
- From the Department of Experimental Radiation Oncology and
| | - Jae-Il Park
- From the Department of Experimental Radiation Oncology and
- Program in Cancer Biology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030
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31
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Imamura S, Yabu T, Yamashita M. Protective role of cell division cycle 48 (CDC48) protein against neurodegeneration via ubiquitin-proteasome system dysfunction during zebrafish development. J Biol Chem 2012; 287:23047-56. [PMID: 22549779 DOI: 10.1074/jbc.m111.332882] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cell division cycle 48 (CDC48), a ubiquitin-dependent molecular chaperone, is thought to mediate a variety of degradative and regulatory processes and maintain cellular homoeostasis. To investigate the protective function of CDC48 against accumulated ubiquitinated proteins during neurodevelopment, we developed an in vivo bioassay technique that detects expression and accumulation of fluorescent proteins with a polyubiquitination signal at the N terminus. When we introduced CDC48 antisense morpholino oligonucleotides into zebrafish embryos, the morphant embryos were lethal and showed defects in neuronal outgrowth and neurodegeneration, and polyubiquitinated fluorescent proteins accumulated in the inner plexiform and ganglion cell layers, as well as the diencephalon and mesencephalon, indicating that the degradation of polyubiquitinated proteins by the ubiquitin-proteasome system was blocked. These abnormal phenotypes in the morphant were rescued by CDC48 or human valosin-containing protein overexpression. Therefore, the protective function of CDC48 is essential for neurodevelopment.
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Affiliation(s)
- Shintaro Imamura
- National Research Institute of Fisheries Science, 2-12-4 Fukuura, Yokohama, Kanagawa 236-8648, Japan
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32
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Zhang Y, Morimoto K, Danilova N, Zhang B, Lin S. Zebrafish models for dyskeratosis congenita reveal critical roles of p53 activation contributing to hematopoietic defects through RNA processing. PLoS One 2012; 7:e30188. [PMID: 22299032 PMCID: PMC3267717 DOI: 10.1371/journal.pone.0030188] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 12/14/2011] [Indexed: 11/19/2022] Open
Abstract
Dyskeratosis congenita (DC) is a rare bone marrow failure syndrome in which hematopoietic defects are the main cause of mortality. The most studied gene responsible for DC pathogenesis is DKC1 while mutations in several other genes encoding components of the H/ACA RNP telomerase complex, which is involved in ribosomal RNA(rRNA) processing and telomere maintenance, have also been implicated. GAR1/nola1 is one of the four core proteins of the H/ACA RNP complex. Through comparative analysis of morpholino oligonucleotide induced knockdown of dkc1 and a retrovirus insertion induced mutation of GAR1/nola1 in zebrafish, we demonstrate that hematopoietic defects are specifically recapitulated in these models and that these defects are significantly reduced in a p53 null mutant background. We further show that changes in telomerase activity are undetectable at the early stages of DC pathogenesis but rRNA processing is clearly defective. Our data therefore support a model that deficiency in dkc1 and nola1 in the H/ACA RNP complex likely contributes to the hematopoietic phenotype through p53 activation associated with rRNA processing defects rather than telomerase deficiency during the initial stage of DC pathogenesis.
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Affiliation(s)
- Ying Zhang
- Laboratory of Chemical Genomics, Shenzhen Graduate School, Peking University, Shenzhen, China
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33
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Taylor AM, Humphries JM, White RM, Murphey RD, Burns CE, Zon LI. Hematopoietic defects in rps29 mutant zebrafish depend upon p53 activation. Exp Hematol 2011; 40:228-237.e5. [PMID: 22120640 DOI: 10.1016/j.exphem.2011.11.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 10/11/2011] [Accepted: 11/22/2011] [Indexed: 11/27/2022]
Abstract
Disruption of ribosomal proteins is associated with hematopoietic phenotypes in cell culture and animal models. Mutations in ribosomal proteins are seen in patients with Diamond Blackfan anemia, a rare congenital disease characterized by red cell aplasia and distinctive craniofacial anomalies. A zebrafish screen uncovered decreased hematopoietic stem cells in embryos with mutations in ribosomal protein rps29. Here, we determined that rps29(-/-) embryos also have red blood cell defects and increased apoptosis in the head. As the p53 pathway has been shown to play a role in other ribosomal protein mutants, we studied the genetic relationship of rps29 and p53. Transcriptional profiling revealed that genes upregulated in the rps29 mutant are enriched for genes upregulated by p53 after irradiation. p53 mutation near completely rescues the rps29 morphological and hematopoietic phenotypes, demonstrating that p53 mediates the effects of rps29 knockdown. We also identified neuronal gene orthopedia protein a (otpa) as one whose expression correlates with rps29 expression, suggesting that levels of expression of some genes are dependent on rps29 levels. Together, our studies demonstrate a role of p53 in mediating the cellular defects associated with rps29 and establish a role for rps29 and p53 in hematopoietic stem cells and red blood cell development.
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Affiliation(s)
- Alison M Taylor
- Stem Cell Program and Division of Hematology/Oncology, Children's Hospital Boston and Dana Farber Cancer Institute, Boston, Mass., USA
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34
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Kishi S. The search for evolutionary developmental origins of aging in zebrafish: A novel intersection of developmental and senescence biology in the zebrafish model system. ACTA ACUST UNITED AC 2011; 93:229-48. [DOI: 10.1002/bdrc.20217] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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35
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Prolonged self-renewal activity unmasks telomerase control of telomere homeostasis and function of mouse hematopoietic stem cells. Blood 2011; 118:1766-73. [PMID: 21730353 DOI: 10.1182/blood-2010-11-319632] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Strategies for expanding hematopoietic stem cells (HSCs) could have significant utility for transplantation-based therapies. However, deleterious consequences of such manipulations remain unknown. Here we examined the impact of HSC self-renewal divisions in vitro and in vivo on their subsequent regenerative and continuing ability to sustain blood cell production in the absence of telomerase. HSC expansion in vitro was obtained using a NUP98-HOXA10hd transduction strategy and, in vivo, using a serial transplant protocol. We observed ~ 10kb telomere loss in leukocytes produced in secondary mice transplanted with HSCs regenerated in primary recipients of NUP98-HOXA10hd-transduced and in vitro-expanded Tert(-/-) HSCs 6 months before. The second generation leukocytes also showed elevated expression of γH2AX (relative to control) indicative of greater accumulating DNA damage. In contrast, significant telomere shortening was not detected in leukocytes produced from freshly isolated, serially transplanted wild-type (WT) or Tert(-/-) HSCs, suggesting that HSC replication posttransplant is not limited by telomere shortening in the mouse. These findings document a role of telomerase in telomere homeostasis, and in preserving HSC functional integrity on prolonged self-renewal stimulation.
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36
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Maintenance of tumor initiating cells of defined genetic composition by nucleostemin. Proc Natl Acad Sci U S A 2011; 108:20388-93. [PMID: 21730156 DOI: 10.1073/pnas.1015171108] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Recent work has identified a subset of cells resident in tumors that exhibit properties similar to those found in normal stem cells. Such cells are highly tumorigenic and may be involved in resistance to treatment. However, the genes that regulate the tumor initiating cell (TIC) state are unknown. Here, we show that overexpression of either of the nucleolar GTP-binding proteins nucleostemin (NS) or GNL3L drives the fraction of genetically defined tumor cells that exhibit markers and tumorigenic properties of TICs. Specifically, cells that constitutively express elevated levels of NS or GNL3L exhibit increased TWIST expression, phosphorylation of STAT3, expression of genes that induce pluripotent stem cells, and enhanced radioresistance; in addition, they form tumors even when small numbers of cells are implanted and exhibit an increased propensity to metastasize. GNL3L/NS forms a complex with the telomerase catalytic subunit [human telomerase reverse transcriptase (hTERT)] and the SWItch-Sucrose NonFermentable (SWI-SNF) complex protein brahma-related gene 1 (BRG1), and the expression of each of these components is necessary to facilitate the cancer stem cell state. Together, these observations define a complex composed of TERT, BRG1, and NS/GNL3L that maintains the function of TICs.
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37
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Xie Y, Yang D, He Q, Songyang Z. Zebrafish as a model system to study the physiological function of telomeric protein TPP1. PLoS One 2011; 6:e16440. [PMID: 21311760 PMCID: PMC3032778 DOI: 10.1371/journal.pone.0016440] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 12/16/2010] [Indexed: 01/08/2023] Open
Abstract
Telomeres are specialized chromatin structures at the end of chromosomes. Telomere dysfunction can lead to chromosomal abnormalities, DNA damage responses, and even cancer. In mammalian cells, a six-protein complex (telosome/shelterin) is assembled on the telomeres through the interactions between various domain structures of the six telomere proteins (POT1, TPP1, TIN2, TRF1, TRF2 and RAP1), and functions in telomere maintenance and protection. Within the telosome, TPP1 interacts directly with POT1 and TIN2 and help to mediate telosome assembly. Mechanisms of telomere regulation have been extensively studied in a variety of model organisms. For example, the physiological roles of telomere-targeted proteins have been assessed in mice through homozygous inactivation. In these cases, early embryonic lethality has prevented further studies of these proteins in embryogenesis and development. As a model system, zebrafish offers unique advantages such as genetic similarities with human, rapid developmental cycles, and ease of manipulation of its embryos. In this report, we detailed the identification of zebrafish homologues of TPP1, POT1, and TIN2, and showed that the domain structures and interactions of these telosome components appeared intact in zebrafish. Importantly, knocking down TPP1 led to multiple abnormalities in zebrafish embryogenesis, including neural death, heart malformation, and caudal defect. And these embryos displayed extensive apoptosis. These results underline the importance of TPP1 in zebrafish embryogenesis, and highlight the feasibility and advantages of investigating the signaling pathways and physiological function of telomere proteins in zebrafish.
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Affiliation(s)
- Yiying Xie
- Verna and Marrs McLean Department of Biochemistry and Molecular biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Dong Yang
- Verna and Marrs McLean Department of Biochemistry and Molecular biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Quanyuan He
- Verna and Marrs McLean Department of Biochemistry and Molecular biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Zhou Songyang
- State Key laboratory for Biocontrol, Sun Yat-Sen University, Guangzhou, People's Republic of China
- * E-mail:
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38
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Maritz MF, Napier CE, Wen VW, MacKenzie KL. Targeting telomerase in hematologic malignancy. Future Oncol 2010; 6:769-89. [PMID: 20465390 DOI: 10.2217/fon.10.42] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Over the past two decades, it has become increasingly apparent that telomerase-mediated telomere maintenance plays a crucial role in hematopoiesis. Supporting evidence is underscored by recent findings of mutations in genes involved in telomerase-mediated telomere maintenance that contribute to the pathogenesis of bone marrow failure syndromes. More recently described telomere-independent functions of telomerase are also likely to contribute to both normal hematopoiesis and hematologic diseases. The high levels of telomerase detected in aggressive leukemias have fueled fervent investigation into diverse approaches to targeting telomerase in hematologic malignancies. Successful preclinical investigations that employed genetic strategies, oligonucleotides, small-molecule inhibitors and immunotherapy have resulted in a rapid translation to clinical trials. Further investigation of telomere-independent functions of telomerase and detailed preclinical studies of telomerase inhibition in both normal and malignant hematopoiesis will be invaluable for refining treatments to effectively and safely exploit telomerase as a therapeutic target in hematologic malignancies.
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Affiliation(s)
- Michelle F Maritz
- Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, New South Wales, Australia
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Abstract
Myriad genetic and epigenetic alterations are required to drive normal cells toward malignant transformation. These somatic events commandeer many signaling pathways that cooperate to endow aspiring cancer cells with a full range of biological capabilities needed to grow, disseminate and ultimately kill its host. Cancer genomes are highly rearranged and are characterized by complex translocations and regional copy number alterations that target loci harboring cancer-relevant genes. Efforts to uncover the underlying mechanisms driving genome instability in cancer have revealed a prominent role for telomeres. Telomeres are nucleoprotein structures that protect the ends of eukaryotic chromosomes and are particularly vulnerable due to progressive shortening during each round of DNA replication and, thus, a lifetime of tissue renewal places the organism at risk for increasing chromosomal instability. Indeed, telomere erosion has been documented in aging tissues and hyperproliferative disease states-conditions strongly associated with increased cancer risk. Telomere dysfunction can produce the opposing pathophysiological states of degenerative aging or cancer with the specific outcome dictated by the integrity of DNA damage checkpoint responses. In most advanced cancers, telomerase is reactivated and serves to maintain telomere length and emerging data have also documented the capacity of telomerase to directly regulate cancer-promoting pathways. This review covers the role of telomeres and telomerase in the biology of normal tissue stem/progenitor cells and in the development of cancer.
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Affiliation(s)
- Steven E Artandi
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Vidal-Cardenas SL, Greider CW. Comparing effects of mTR and mTERT deletion on gene expression and DNA damage response: a critical examination of telomere length maintenance-independent roles of telomerase. Nucleic Acids Res 2009; 38:60-71. [PMID: 19850716 PMCID: PMC2800220 DOI: 10.1093/nar/gkp855] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Telomerase, the essential enzyme that maintains telomere length, contains two core components, TERT and TR. Early studies in yeast and mouse showed that loss of telomerase leads to phenotypes only after several generations, due to telomere shortening. However, recent studies have suggested additional roles for telomerase components in transcription and the response to DNA damage. To examine these potential telomere length maintenance-independent roles of telomerase components, we examined first generation mTR(-/-) and mTERT(-/-) mice with long telomeres. We used gene expression profiling and found no genes that were differentially expressed in mTR(-/-) G1 mice and mTERT(-/-) G1 mice compared with wild-type mice. We also compared the response to DNA damage in mTR(-/-)G1 and mTERT(-/-) G1 mouse embryonic fibroblasts, and found no increase in the response to DNA damage in the absence of either telomerase component compared to wild-type. We conclude that, under physiologic conditions, neither mTR nor mTERT acts as a transcription factor or plays a role in the DNA damage response.
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Affiliation(s)
- Sofia L Vidal-Cardenas
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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41
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Telomerase modulates Wnt signalling by association with target gene chromatin. Nature 2009; 460:66-72. [PMID: 19571879 DOI: 10.1038/nature08137] [Citation(s) in RCA: 501] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Accepted: 05/13/2009] [Indexed: 12/18/2022]
Abstract
Stem cells are controlled, in part, by genetic pathways frequently dysregulated during human tumorigenesis. Either stimulation of Wnt/beta-catenin signalling or overexpression of telomerase is sufficient to activate quiescent epidermal stem cells in vivo, although the mechanisms by which telomerase exerts these effects are not understood. Here we show that telomerase directly modulates Wnt/beta-catenin signalling by serving as a cofactor in a beta-catenin transcriptional complex. The telomerase protein component TERT (telomerase reverse transcriptase) interacts with BRG1 (also called SMARCA4), a SWI/SNF-related chromatin remodelling protein, and activates Wnt-dependent reporters in cultured cells and in vivo. TERT serves an essential role in formation of the anterior-posterior axis in Xenopus laevis embryos, and this defect in Wnt signalling manifests as homeotic transformations in the vertebrae of Tert(-/-) mice. Chromatin immunoprecipitation of the endogenous TERT protein from mouse gastrointestinal tract shows that TERT physically occupies gene promoters of Wnt-dependent genes. These data reveal an unanticipated role for telomerase as a transcriptional modulator of the Wnt/beta-catenin signalling pathway.
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Deville L, Hillion J, Ségal-Bendirdjian E. Telomerase regulation in hematological cancers: a matter of stemness? Biochim Biophys Acta Mol Basis Dis 2009; 1792:229-39. [PMID: 19419697 DOI: 10.1016/j.bbadis.2009.01.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 01/30/2009] [Accepted: 01/30/2009] [Indexed: 01/02/2023]
Abstract
Human telomerase is a nuclear ribonucleoprotein enzyme complex that catalyzes the synthesis and extension of telomeric DNA. This enzyme is highly expressed and active in most malignant tumors while it is usually not or transiently detectable in normal somatic cells, suggesting that it plays an important role in cellular immortalization and tumorigenesis. As most leukemic cells are generally telomerase-positive and have often shortened telomeres, our understanding of how telomerase is deregulated in these diseases could help to define novel therapies targeting the telomere/telomerase complex. Nonetheless, considering that normal hematopoietic stem cells and some of their progeny do express a functional telomerase, it is tempting to consider such an activity in leukemias as a sustained stemness feature and important to understand how telomere length and telomerase activity are regulated in the various forms of leukemias.
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Affiliation(s)
- Laure Deville
- INSERM UMR-S 685, Institut d'Hématologie, Hôpital Saint-Louis, 75475 Paris cedex 10, France
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