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Yu HJ, Byun YH, Park CK. Techniques for assessing telomere length: A methodological review. Comput Struct Biotechnol J 2024; 23:1489-1498. [PMID: 38633384 PMCID: PMC11021795 DOI: 10.1016/j.csbj.2024.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 04/19/2024] Open
Abstract
Telomeres are located at the ends of chromosomes and have specific sequences with a distinctive structure that safeguards genes. They possess capping structures that protect chromosome ends from fusion events and ensure chromosome stability. Telomeres shorten in length during each cycle of cell division. When this length reaches a certain threshold, it can lead to genomic instability, thus being implicated in various diseases, including cancer and neurodegenerative disorders. The possibility of telomeres serving as a biomarker for aging and age-related disease is being explored, and their significance is still under study. This is because post-mitotic cells, which are mature cells that do not undergo mitosis, do not experience telomere shortening due to age. Instead, other causes, for example, exposure to oxidative stress, can directly damage the telomeres, causing genomic instability. Nonetheless, a general agreement has been established that measuring telomere length offers valuable insights and forms a crucial foundation for analyzing gene expression and epigenetic data. Numerous approaches have been developed to accurately measure telomere lengths. In this review, we summarize various methods and their advantages and limitations for assessing telomere length.
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Affiliation(s)
- Hyeon Jong Yu
- Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Yoon Hwan Byun
- Department of Neurosurgery, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea
| | - Chul-Kee Park
- Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
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2
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Sanchez SE, Gu Y, Wang Y, Golla A, Martin A, Shomali W, Hockemeyer D, Savage SA, Artandi SE. Digital telomere measurement by long-read sequencing distinguishes healthy aging from disease. Nat Commun 2024; 15:5148. [PMID: 38890274 PMCID: PMC11189511 DOI: 10.1038/s41467-024-49007-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 05/21/2024] [Indexed: 06/20/2024] Open
Abstract
Telomere length is an important biomarker of organismal aging and cellular replicative potential, but existing measurement methods are limited in resolution and accuracy. Here, we deploy digital telomere measurement (DTM) by nanopore sequencing to understand how distributions of human telomere length change with age and disease. We measure telomere attrition and de novo elongation with up to 30 bp resolution in genetically defined populations of human cells, in blood cells from healthy donors and in blood cells from patients with genetic defects in telomere maintenance. We find that human aging is accompanied by a progressive loss of long telomeres and an accumulation of shorter telomeres. In patients with defects in telomere maintenance, the accumulation of short telomeres is more pronounced and correlates with phenotypic severity. We apply machine learning to train a binary classification model that distinguishes healthy individuals from those with telomere biology disorders. This sequencing and bioinformatic pipeline will advance our understanding of telomere maintenance mechanisms and the use of telomere length as a clinical biomarker of aging and disease.
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Affiliation(s)
- Santiago E Sanchez
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
- Cancer Biology Program, Stanford University School of Medicine, Stanford, CA, USA
- Medical Scientist Training Program, Stanford University, Stanford, CA, USA
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - Yuchao Gu
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - Yan Wang
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - Anudeep Golla
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Annika Martin
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - William Shomali
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Sharon A Savage
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA
| | - Steven E Artandi
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA.
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA.
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA.
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3
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Savage SA. Telomere length and cancer risk: finding Goldilocks. Biogerontology 2024; 25:265-278. [PMID: 38109000 DOI: 10.1007/s10522-023-10080-9] [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: 08/22/2023] [Accepted: 11/13/2023] [Indexed: 12/19/2023]
Abstract
Telomeres are the nucleoprotein complex at chromosome ends essential in genomic stability. Baseline telomere length (TL) is determined by rare and common germline genetic variants but shortens with age and is susceptible to certain environmental exposures. Cellular senescence or apoptosis are normally triggered when telomeres reach a critically short length, but cancer cells overcome these protective mechanisms and continue to divide despite chromosomal instability. Rare germline variants in telomere maintenance genes cause exceedingly short telomeres for age (< 1st percentile) and the telomere biology disorders, which are associated with elevated risks of bone marrow failure, myelodysplastic syndrome, acute myeloid leukemia, and squamous cell carcinoma of the head/neck and anogenital regions. Long telomeres due to rare germline variants in the same or different telomere maintenance genes are associated with elevated risks of other cancers, such as chronic lymphocytic leukemia or sarcoma. Early epidemiology studies of TL in the general population lacked reproducibility but new methods, including creation of a TL polygenic score using common variants, have found longer telomeres associated with excess risks of renal cell carcinoma, glioma, lung cancer, and others. It has become clear that when it comes to TL and cancer etiology, not too short, not too long, but "just right" telomeres are important in minimizing cancer risk.
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Affiliation(s)
- Sharon A Savage
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 9609 Medical Center Drive, 6E456, Bethesda, MD, 20892-6772, USA.
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Niewisch MR. Clinical manifestations of telomere biology disorders in adults. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2023; 2023:563-572. [PMID: 38066848 PMCID: PMC10726987 DOI: 10.1182/hematology.2023000490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Telomere biology disorders (TBDs) are a spectrum of inherited bone marrow failure syndromes caused by impaired telomere function due to pathogenic germline variants in genes involved in telomere maintenance. TBDs can affect many organ systems and are often thought of as diseases of childhood. However, TBDs may present in mid- or even late adulthood with features similar to but not always the same as the childhood-onset TBDs. Adult-onset TBDs are often cryptic with isolated pulmonary, liver, or hematologic disease, or cancer, and may lack the classic disease-defining triad of abnormal skin pigmentation, nail dysplasia, and oral leukoplakia. Diagnostics include detection of very short leukocyte telomeres and germline genetic testing. Notably, adult-onset TBDs may show telomeres in the 1st to 10th percentile for age, and some cases may not have an identifiable genetic cause. TBD genetic etiology includes all modes of inheritance, with autosomal dominant the most frequent in adult-onset disease. Variable symptom onset due to incomplete penetrance, variable expressivity, and genetic anticipation add to the diagnostic challenges. Adult-onset TBDs are likely underrecognized, but their correct identification is of utmost importance, since affected patients are faced with numerous clinical complications, including but not limited to an increased risk of malignancies requiring close surveillance for early detection. Currently lung, liver, or hematopoietic cell transplants are the only curative therapeutic approaches but can be complicated by comorbidities, despite improved medical care. This review highlights the challenges of identifying adult-onset TBDs and addresses currently recommended clinical screening measures and therapy options.
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Affiliation(s)
- Marena R. Niewisch
- Department of Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
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Ongie L, Raj HA, Stevens KB. Genetic Counseling and Family Screening Recommendations in Patients with Telomere Biology Disorders. Curr Hematol Malig Rep 2023; 18:273-283. [PMID: 37787873 DOI: 10.1007/s11899-023-00713-8] [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] [Accepted: 09/11/2023] [Indexed: 10/04/2023]
Abstract
PURPOSE OF REVIEW Telomere biology disorders (TBDs) encompass a spectrum of genetic diseases with a common pathogenesis of defects in telomerase function and telomere maintenance causing extremely short telomere lengths. Here, we review the current literature surrounding genetic testing strategies, cascade testing, reproductive implications, and the role of genetic counseling. RECENT FINDINGS The understanding of the genetic causes and clinical symptoms of TBDs continues to expand while genetic testing and telomere length testing are nuanced tools utilized in the diagnosis of this condition. Access to genetic counseling is becoming more abundant and is valuable in supporting patients and their families in making informed decisions. Patient resources and support groups are valuable to this community. Defining which populations should be offered genetic counseling and testing is imperative to provide proper diagnoses and medical management for not only the primary patient, but also their biological relatives.
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Affiliation(s)
| | - Hannah A Raj
- Team Telomere, Inc., New York, NY, USA
- College of Medicine, University of Illinois, Chicago, IL, USA
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Raj HA, Lai TP, Niewisch MR, Giri N, Wang Y, Spellman SR, Aviv A, Gadalla SM, Savage SA. The distribution and accumulation of the shortest telomeres in telomere biology disorders. Br J Haematol 2023; 203:820-828. [PMID: 37354000 PMCID: PMC10748793 DOI: 10.1111/bjh.18945] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/19/2023] [Accepted: 06/02/2023] [Indexed: 06/25/2023]
Abstract
Individuals with telomere biology disorders (TBDs) have very short telomeres, high risk of bone marrow failure (BMF), and reduced survival. Using data from TBD patients, a mean leukocyte Southern blot telomere length (TL) of 5 kilobases (kb) was estimated as the 'telomere brink' at which human survival is markedly reduced. However, the shortest telomere, not the mean TL, signals replicative senescence. We used the Telomere Shortest Length Assay (TeSLA) to tally TL of all 46 chromosomes in blood-derived DNA and examined its relationship with TBDs. Patients (n = 18) had much shorter mean TL (TeSmTL) (2.54 ± 0.41 kb vs. 4.48 ± 0.52 kb, p < 0.0001) and more telomeres <3 kb than controls (n = 22) (70.43 ± 8.76% vs. 33.05 ± 6.93%, p < 0.0001). The proportion of ultrashort telomeres (<1.6 kb) was also higher in patients than controls (39.29 ± 10.69% vs. 10.40 ± 4.09%, p < 0.0001). TeS <1.6 kb was associated with severe (n = 11) compared with non-severe (n = 7) BMF (p = 0.027). Patients with multi-organ manifestations (n = 10) had more telomeres <1.6 kb than those with one affected organ system (n = 8) (p = 0.029). Findings suggest that TBD clinical manifestations are associated with a disproportionately higher number of haematopoietic cell telomeres reaching a telomere brink, whose length at the single telomere level is yet to be determined.
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Affiliation(s)
- Hannah A. Raj
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD
| | - Tsung-Po Lai
- Center of Human Development and Aging, Rutgers University of New Jersey, New Jersey Medical School, Newark, NJ
| | - Marena R. Niewisch
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD
- Department of Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | - Neelam Giri
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD
| | - Youjin Wang
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD
| | - Stephen R. Spellman
- Center for International Blood and Marrow Transplant Research, National Marrow Donor Program/Be The Match, Minneapolis, MN
| | - Abraham Aviv
- Center of Human Development and Aging, Rutgers University of New Jersey, New Jersey Medical School, Newark, NJ
| | - Shahinaz M. Gadalla
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD
| | - Sharon A. Savage
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD
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Ferrer A, Stephens ZD, Kocher JPA. Experimental and Computational Approaches to Measure Telomere Length: Recent Advances and Future Directions. Curr Hematol Malig Rep 2023; 18:284-291. [PMID: 37947937 PMCID: PMC10709248 DOI: 10.1007/s11899-023-00717-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2023] [Indexed: 11/12/2023]
Abstract
PURPOSE OF REVIEW The length of telomeres, protective structures at the chromosome ends, is a well-established biomarker for pathological conditions including multisystemic syndromes called telomere biology disorders. Approaches to measure telomere length (TL) differ on whether they estimate average, distribution, or chromosome-specific TL, and each presents their own advantages and limitations. RECENT FINDINGS The development of long-read sequencing and publication of the telomere-to-telomere human genome reference has allowed for scalable and high-resolution TL estimation in pre-existing sequencing datasets but is still impractical as a dedicated TL test. As sequencing costs continue to fall and strategies for selectively enriching telomere regions prior to sequencing improve, these approaches may become a promising alternative to classic methods. Measurement methods rely on probe hybridization, qPCR or more recently, computational methods using sequencing data. Refinements of existing techniques and new approaches have been recently developed but a test that is accurate, simple, and scalable is still lacking.
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Affiliation(s)
- Alejandro Ferrer
- Division of Hematology, Mayo Clinic, Rochester, 200 First Street SW, Rochester, MN, USA.
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.
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Sanchez SE, Gu J, Golla A, Martin A, Shomali W, Hockemeyer D, Savage SA, Artandi SE. Digital telomere measurement by long-read sequencing distinguishes healthy aging from disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.29.569263. [PMID: 38077053 PMCID: PMC10705489 DOI: 10.1101/2023.11.29.569263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Telomere length is an important biomarker of organismal aging and cellular replicative potential, but existing measurement methods are limited in resolution and accuracy. Here, we deploy digital telomere measurement by nanopore sequencing to understand how distributions of human telomere length change with age and disease. We measure telomere attrition and de novo elongation with unprecedented resolution in genetically defined populations of human cells, in blood cells from healthy donors and in blood cells from patients with genetic defects in telomere maintenance. We find that human aging is accompanied by a progressive loss of long telomeres and an accumulation of shorter telomeres. In patients with defects in telomere maintenance, the accumulation of short telomeres is more pronounced and correlates with phenotypic severity. We apply machine learning to train a binary classification model that distinguishes healthy individuals from those with telomere biology disorders. This sequencing and bioinformatic pipeline will advance our understanding of telomere maintenance mechanisms and the use of telomere length as a clinical biomarker of aging and disease.
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Affiliation(s)
- Santiago E. Sanchez
- Stanford Cancer Institute, Stanford University School of Medicine; Stanford, CA, USA
- Cancer Biology Program, Stanford University School of Medicine; Stanford, CA, USA
- Medical Scientist Training Program, Stanford University; Stanford CA, USA
| | - Jessica Gu
- Stanford Cancer Institute, Stanford University School of Medicine; Stanford, CA, USA
- Department of Medicine, Stanford University School of Medicine; Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine; Stanford, CA, USA
| | - Anudeep Golla
- Stanford Cancer Institute, Stanford University School of Medicine; Stanford, CA, USA
| | - Annika Martin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - William Shomali
- Department of Medicine, Stanford University School of Medicine; Stanford, CA, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
- Chan Zuckerberg Biohub, San Francisco, CA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA
| | - Sharon A. Savage
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, USA
| | - Steven E. Artandi
- Stanford Cancer Institute, Stanford University School of Medicine; Stanford, CA, USA
- Department of Medicine, Stanford University School of Medicine; Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine; Stanford, CA, USA
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Bhala S, Savage SA. What is the future of telomere length testing in telomere biology disorders? Expert Rev Hematol 2023; 16:475-478. [PMID: 37191632 PMCID: PMC10330493 DOI: 10.1080/17474086.2023.2215423] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 05/15/2023] [Indexed: 05/17/2023]
Affiliation(s)
- Sonia Bhala
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, USA
| | - Sharon A. Savage
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, USA
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High-throughput telomere length measurement at nucleotide resolution using the PacBio high fidelity sequencing platform. Nat Commun 2023; 14:281. [PMID: 36650155 PMCID: PMC9845338 DOI: 10.1038/s41467-023-35823-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 12/20/2022] [Indexed: 01/19/2023] Open
Abstract
Telomeres are specialized nucleoprotein structures at the ends of linear chromosomes. The progressive shortening of steady-state telomere length in normal human somatic cells is a promising biomarker for age-associated diseases. However, there remain substantial challenges in quantifying telomere length due to the lack of high-throughput method with nucleotide resolution for individual telomere. Here, we describe a workflow to capture telomeres using newly designed telobaits in human culture cell lines as well as clinical patient samples and measure their length accurately at nucleotide resolution using single-molecule real-time (SMRT) sequencing. Our results also reveal the extreme heterogeneity of telomeric variant sequences (TVSs) that are dispersed throughout the telomere repeat region. The presence of TVSs disrupts the continuity of the canonical (5'-TTAGGG-3')n telomere repeats, which affects the binding of shelterin complexes at the chromosomal ends and telomere protection. These findings may have profound implications in human aging and diseases.
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Dyskeratosis congenita and telomere biology disorders. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2022; 2022:637-648. [PMID: 36485133 PMCID: PMC9821046 DOI: 10.1182/hematology.2022000394] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Numerous genetic discoveries and the advent of clinical telomere length testing have led to the recognition of a spectrum of telomere biology disorders (TBDs) beyond the classic dyskeratosis congenita (DC) triad of nail dysplasia, abnormal skin pigmentation, and oral leukoplakia occurring with pediatric bone marrow failure. Patients with DC/TBDs have very short telomeres for their age and are at high risk of bone marrow failure, cancer, pulmonary fibrosis (PF), pulmonary arteriovenous malformations, liver disease, stenosis of the urethra, esophagus, and/or lacrimal ducts, avascular necrosis of the hips and/or shoulders, and other medical problems. However, many patients with TBDs do not develop classic DC features; they may present in middle age and/or with just 1 feature, such as PF or aplastic anemia. TBD-associated clinical manifestations are progressive and attributed to aberrant telomere biology caused by the X-linked recessive, autosomal dominant, autosomal recessive, or de novo occurrence of pathogenic germline variants in at least 18 different genes. This review describes the genetics and clinical manifestations of TBDs and highlights areas in need of additional clinical and basic science research.
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Choo S, Lorbeer FK, Regalado SG, Short SB, Wu S, Rieser G, Bertuch AA, Hockemeyer D. Editing TINF2 as a potential therapeutic approach to restore telomere length in dyskeratosis congenita. Blood 2022; 140:608-618. [PMID: 35421215 PMCID: PMC9373014 DOI: 10.1182/blood.2021013750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 03/25/2022] [Indexed: 11/29/2022] Open
Abstract
Mutations in the TINF2 gene, encoding the shelterin protein TIN2, cause telomere shortening and the inherited bone marrow (BM) failure syndrome dyskeratosis congenita (DC). A lack of suitable model systems limits the mechanistic understanding of telomere shortening in the stem cells and thus hinders the development of treatment options for BM failure. Here, we endogenously introduced TIN2-DC mutations in human embryonic stem cells (hESCs) and human hematopoietic stem and progenitor cells (HSPCs) to dissect the disease mechanism and identify a gene-editing strategy that rescued the disease phenotypes. The hESCs with the T284R disease mutation exhibited the short telomere phenotype observed in DC patients. Yet, telomeres in mutant hESCs did not trigger DNA damage responses at telomeres or show exacerbated telomere shortening when differentiated into telomerase-negative cells. Disruption of the mutant TINF2 allele by introducing a frameshift mutation in exon 2 restored telomere length in stem cells and the replicative potential of differentiated cells. Similarly, we introduced TIN2-DC disease variants in human HSPCs to assess the changes in telomere length and proliferative capacity. Lastly, we showed that editing at exon 2 of TINF2 that restored telomere length in hESCs could be generated in TINF2-DC patient HSPCs. Our study demonstrates a simple genetic intervention that rescues the TIN2-DC disease phenotype in stem cells and provides a versatile platform to assess the efficacy of potential therapeutic approaches in vivo.
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Affiliation(s)
- Seunga Choo
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Franziska K Lorbeer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Samuel G Regalado
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Sarah B Short
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Shannon Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Gabrielle Rieser
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Alison A Bertuch
- Department of Pediatrics, Baylor College of Medicine, Houston, TX
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
- Chan Zuckerberg Biohub, San Francisco, CA; and
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA
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Stephens Z, Ferrer A, Boardman L, Iyer RK, Kocher JPA. Telogator: a method for reporting chromosome-specific telomere lengths from long reads. Bioinformatics 2022; 38:1788-1793. [PMID: 35022670 PMCID: PMC8963315 DOI: 10.1093/bioinformatics/btac005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 12/17/2021] [Indexed: 02/03/2023] Open
Abstract
MOTIVATION Telomeres are the repetitive sequences found at the ends of eukaryotic chromosomes and are often thought of as a 'biological clock,' with their average length shortening during division in most cells. In addition to their association with senescence, abnormal telomere lengths are well known to be associated with multiple cancers, short telomere syndromes and as risk factors for a broad range of diseases. While a majority of methods for measuring telomere length will report average lengths across all chromosomes, it is known that aberrations in specific chromosome arms are biomarkers for certain diseases. Due to their repetitive nature, characterizing telomeres at this resolution is prohibitive for short read sequencing approaches, and is challenging still even with longer reads. RESULTS We present Telogator: a method for reporting chromosome-specific telomere length from long read sequencing data. We demonstrate Telogator's sensitivity in detecting chromosome-specific telomere length in simulated data across a range of read lengths and error rates. Telogator is then applied to 10 germline samples, yielding a high correlation with short read methods in reporting average telomere length. In addition, we investigate common subtelomere rearrangements and identify the minimum read length required to anchor telomere/subtelomere boundaries in samples with these haplotypes. AVAILABILITY AND IMPLEMENTATION Telogator is written in Python3 and is available at github.com/zstephens/telogator. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Zachary Stephens
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | | | - Lisa Boardman
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55902, USA
| | - Ravishankar K Iyer
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
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