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Teramoto N, Okada Y, Aburada N, Hayashi M, Ito J, Shirasuna K, Iwata H. Resveratrol intake by males increased the mitochondrial DNA copy number and telomere length of blastocysts derived from aged mice. J Reprod Dev 2024; 70:247-253. [PMID: 38945863 PMCID: PMC11310382 DOI: 10.1262/jrd.2024-043] [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: 04/26/2024] [Accepted: 06/03/2024] [Indexed: 07/02/2024] Open
Abstract
The present study examined whether male resveratrol intake affected mitochondrial DNA copy number (mt-cn) and telomere length (TL) in blastocysts fathered by young and aged male mice. C57BL/6N male mice supplied with water or water containing 0.1 mM resveratrol were used for embryo production at 14-23 and 48-58 weeks of age. Two-cell-stage embryos were collected from the oviducts of superovulated female mice (8-15 weeks old) and cultured for 3 days until the blastocyst stage. Mt-cn and TL levels were measured by real-time polymerase chain reaction. Resveratrol intake did not affect body weight or water consumption. Resveratrol intake increased the expression levels of SIRT1 in the liver, the antioxidative ability of serum, and extended TL in the heart, whereas there was no significant difference in mt-cn in the heart or TL in sperm. The rate of blastocyst development was significantly lower in aged male mice than in younger mice, and resveratrol intake increased the total number of blastocysts derived from both young and aged males. Resveratrol intake did not affect mt-cn or TL in blastomeres of blastocyst-stage embryos derived from young mice, but significantly increased both mt-cn and TL in blastomeres of blastocysts derived from aged fathers. In conclusion, resveratrol intake increased mt-cn and TL levels in blastocysts derived from aged male mice.
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Affiliation(s)
- Noko Teramoto
- Department of Animal Science, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Yuri Okada
- Department of Animal Science, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Nao Aburada
- Department of Animal Science, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Masamune Hayashi
- Department of Animal Science, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Jun Ito
- Department of Animal Science, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Komei Shirasuna
- Department of Animal Science, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Hisataka Iwata
- Department of Animal Science, Tokyo University of Agriculture, Tokyo 156-8502, Japan
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2
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Inoue Y, Aoki S, Ito J, Hara S, Shirasuna K, Iwata H. Telomere length determines the mitochondrial copy number in blastocyst-stage embryos. Mitochondrion 2024; 77:101887. [PMID: 38663837 DOI: 10.1016/j.mito.2024.101887] [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: 02/22/2024] [Revised: 04/17/2024] [Accepted: 04/22/2024] [Indexed: 05/07/2024]
Abstract
Telomere length (TL) and mitochondrial DNA copy number (mt-cn) are associated with embryonic development. Here, we investigated the correlation between TL and mt-cn in bovine embryos to determine whether TL regulates mt-cn. TL and mt-cn were closely correlated in embryos derived from six bulls. Treatment of embryos with a telomerase inhibitor (TMPyP) and siTERT shortened the TL and reduced mt-cn in blastocysts. RNA-sequencing of blastocysts developed with TMPyP revealed differentially expressed genes associated with transforming growth factor-β1 signaling and inflammation. In conclusion, TL regulates mt-cn in embryos.
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Affiliation(s)
- Yuki Inoue
- Tokyo University of Agriculture, Department of Animal Science, Atsugi, Kanagawa 243-0034, Japan
| | - Sogo Aoki
- Tokyo University of Agriculture, Department of Animal Science, Atsugi, Kanagawa 243-0034, Japan
| | - Jun Ito
- Tokyo University of Agriculture, Department of Animal Science, Atsugi, Kanagawa 243-0034, Japan
| | - Shunsuke Hara
- Tokyo University of Agriculture, Department of Animal Science, Atsugi, Kanagawa 243-0034, Japan
| | - Komei Shirasuna
- Tokyo University of Agriculture, Department of Animal Science, Atsugi, Kanagawa 243-0034, Japan
| | - Hisataka Iwata
- Tokyo University of Agriculture, Department of Animal Science, Atsugi, Kanagawa 243-0034, Japan.
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3
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Fragkiadaki P, Kouvidi E, Angelaki A, Nikolopoulou D, Vakonaki E, Tsatsakis A. Evaluation of telomere length and telomerase activity on predicting in vitro fertilization treatment outcomes. J Assist Reprod Genet 2024; 41:1463-1473. [PMID: 38695985 PMCID: PMC11224194 DOI: 10.1007/s10815-024-03117-6] [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: 11/21/2023] [Accepted: 04/03/2024] [Indexed: 07/05/2024] Open
Abstract
The current article is a literature review aiming to provide an overview of the existing knowledge on the association between telomere length and telomerase activity and in vitro fertilization. Recently, telomeres have been used as an effective biomarker to determine biological age, which may differ from chronological age due to genetic, lifestyle, and environmental factors. Cellular senescence, along with other exogenous and mainly environmental factors, can enhance telomere wear, further shortening their ends and may also affect reproductive aging. IVF is a common fertility treatment caused by female reasons (age, ovulation disorders, damaged or blocked fallopian tubes, endometriosis), male reasons (low sperm quantity or quality), or unexplained infertility. A growing number of studies have proposed a relationship between telomere length and telomerase activity and IVF success and have suggested their use as candidate biomarkers for IVF outcome. Nevertheless, additional studies are necessary to be conducted, in order to clarify the possible implication of telomeres in IVF and to evaluate their possible role as valuable predictors of IVF result.
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Affiliation(s)
- Persefoni Fragkiadaki
- Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, Voutes, 71003, Heraklion, Greece
- Lifeplus S.A., Science &Technological Park of Crete, C Building, Vassilika Vouton, 70013, Heraklion, Crete, Greece
| | - Elisavet Kouvidi
- Lifeplus S.A., Science &Technological Park of Crete, C Building, Vassilika Vouton, 70013, Heraklion, Crete, Greece
- Phenotypos Lab, Katehaki 40A, 115 25, Athens, Greece
| | - Anna Angelaki
- Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, Voutes, 71003, Heraklion, Greece
| | - Dimitra Nikolopoulou
- Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, Voutes, 71003, Heraklion, Greece
- Lifeplus S.A., Science &Technological Park of Crete, C Building, Vassilika Vouton, 70013, Heraklion, Crete, Greece
| | - Elena Vakonaki
- Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, Voutes, 71003, Heraklion, Greece
- Lifeplus S.A., Science &Technological Park of Crete, C Building, Vassilika Vouton, 70013, Heraklion, Crete, Greece
| | - Aristidis Tsatsakis
- Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, Voutes, 71003, Heraklion, Greece.
- Lifeplus S.A., Science &Technological Park of Crete, C Building, Vassilika Vouton, 70013, Heraklion, Crete, Greece.
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4
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Córdova-Oriz I, Polonio AM, Cuadrado-Torroglosa I, Chico-Sordo L, Medrano M, García-Velasco JA, Varela E. Chromosome ends and the theory of marginotomy: implications for reproduction. Biogerontology 2024; 25:227-248. [PMID: 37943366 DOI: 10.1007/s10522-023-10071-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/21/2023] [Indexed: 11/10/2023]
Abstract
Telomeres are the protective structures located at the ends of linear chromosomes. They were first described in the 1930s, but their biology remained unexplored until the early 70s, when Alexey M. Olovnikov, a theoretical biologist, suggested that telomeres cannot be fully copied during DNA replication. He proposed a theory that linked this phenomenon with the limit of cell proliferation capacity and the "duration of life" (theory of marginotomy), and suggested a potential of telomere lenghthening for the prevention of aging (anti-marginotomy). The impact of proliferative telomere shortening on life expectancy was later confirmed. In humans, telomere shortening is counteracted by telomerase, an enzyme that is undetectable in most adult somatic cells, but present in cancer cells and adult and embryonic stem and germ cells. Although telomere length dynamics are different in male and female gametes during gametogenesis, telomere lengths are reset at the blastocyst stage, setting the initial length of the species. The role of the telomere pathway in reproduction has been explored for years, mainly because of increased infertility resulting from delayed childbearing. Short telomere length in ovarian somatic cells is associated to decreased fertility and higher aneuploidy rates in embryos. Consequently, there is a growing interest in telomere lengthening strategies, aimed at improving fertility. It has also been observed that lifestyle factors can affect telomere length and improve fertility outcomes. In this review, we discuss the implications of telomere theory in fertility, especially in oocytes, spermatozoa, and embryos, as well as therapies to enhance reproductive success.
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Affiliation(s)
- Isabel Córdova-Oriz
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Alba M Polonio
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Isabel Cuadrado-Torroglosa
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Lucía Chico-Sordo
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Marta Medrano
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Juan A García-Velasco
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
- IVIRMA Global Research Alliance, IVIRMA Madrid, Madrid, Spain
- Department of Medical Specialties and Public Health, Edificio Departamental II, Rey Juan Carlos University, Av. de Atenas, s/n, 28922, Alcorcón, Madrid, Spain
| | - Elisa Varela
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain.
- Department of Medical Specialties and Public Health, Edificio Departamental II, Rey Juan Carlos University, Av. de Atenas, s/n, 28922, Alcorcón, Madrid, Spain.
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Frydrychová RČ, Konopová B, Peska V, Brejcha M, Sábová M. Telomeres and telomerase: active but complex players in life-history decisions. Biogerontology 2024; 25:205-226. [PMID: 37610666 DOI: 10.1007/s10522-023-10060-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 08/24/2023]
Abstract
Studies on human telomeres have established that telomeres exert a significant influence on lifespan and health of organisms. However, recent research has indicated that the original idea that telomeres affect lifespan in a universal and central manner across all eukaryotic species is an oversimplification. Indeed, findings from a variety of animal species revealed that the role of telomere biology in aging is more subtle and intricate than previously recognized. Here, we show how telomere biology varies depending on the taxon. We also show how telomere biology corresponds to basic life history traits and affects the life table of a species and investments in growth, body size, reproduction, and lifespan; telomeres are hypothesized to shape evolutionary perspectives for species in an active but complex manner. Our evaluation is based on telomere biology data from many examples from throughout the animal kingdom that vary according to the degree of organismal complexity and life history strategies.
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Affiliation(s)
- Radmila Čapková Frydrychová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic.
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, Ceske Budejovice, Czech Republic.
| | - Barbora Konopová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
| | - Vratislav Peska
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 00, Brno, Czech Republic
| | - Miloslav Brejcha
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, Ceske Budejovice, Czech Republic
| | - Michala Sábová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
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Chien CW, Tang YA, Jeng SL, Pan HA, Sun HS. Blastocyst telomere length predicts successful implantation after frozen-thawed embryo transfer. Hum Reprod Open 2024; 2024:hoae012. [PMID: 38515829 PMCID: PMC10955253 DOI: 10.1093/hropen/hoae012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 02/04/2024] [Indexed: 03/23/2024] Open
Abstract
STUDY QUESTION Do embryos with longer telomere length (TL) at the blastocyst stage have a higher capacity to survive after frozen-thawed embryo transfer (FET)? SUMMARY ANSWER Digitally estimated TL using low-pass whole genome sequencing (WGS) data from the preimplantation genetic testing for aneuploidy (PGT-A) process demonstrates that blastocyst TL is the most essential factor associated with likelihood of implantation. WHAT IS KNOWN ALREADY The lifetime TL is established in the early cleavage cycles following fertilization through a recombination-based lengthening mechanism and starts erosion beyond the blastocyst stage. In addition, a telomerase-mediated slow erosion of TL in human fetuses has been observed from a gestational age of 6-11 weeks. Finally, an abnormal shortening of telomeres is likely involved in embryo loss during early development. STUDY DESIGN SIZE DURATION Blastocyst samples were obtained from patients who underwent PGT-A and FET in an IVF center from March 2015 to May 2018. Digitally estimated mitochondrial copy number (mtCN) and TL were used to study associations with the implantation potential of each embryo. PARTICIPANTS/MATERIALS SETTING AND METHODS In total, 965 blastocysts from 232 cycles (164 patients) were available to investigate the biological and clinical relevance of TL. A WGS-based workflow was applied to determine the ploidy of each embryo. Data from low-pass WGS-PGT-A were used to estimate the mtCN and TL for each embryo. Single-variant and multi-variant logistic regression, decision tree, and random forest models were applied to study various factors in association with the implantation potential of each embryo. MAIN RESULTS AND THE ROLE OF CHANCE Of the 965 blastocysts originally available, only 216 underwent FET. While mtCN from the transferred embryos is significantly associated with the ploidy call of each embryo, mtCN has no role in impacting IVF outcomes after an embryo transfer in these women. The results indicate that mtCN is a marker of embryo aneuploidy. On the other hand, digitally estimated TL is the most prominent univariant factor and showed a significant positive association with pregnancy outcomes (P < 0.01, odds ratio 79.1). We combined several maternal and embryo parameters to study the joint effects on successful implantation. The machine learning models, namely decision tree and random forest, were trained and yielded classification accuracy of 0.82 and 0.91, respectively. Taken together, these results support the vital role of TL in governing implantation potential, perhaps through the ability to control embryo survival after transfer. LIMITATIONS REASONS FOR CAUTION The small sample size limits our study as only 216 blastocysts were transferred. The number was further reduced to 153 blastocysts, where pregnancy outcomes could be accurately traced. The other limitation of this study is that all data were collected from a single IVF center. The uniform and controlled operation of IVF cycles in a single center may cause selection bias. WIDER IMPLICATIONS OF THE FINDINGS We present novel findings to show that digitally estimated TL at the blastocyst stage is a predictor of pregnancy capacity after a FET cycle. As elective single-embryo transfer has become the mainstream direction in reproductive medicine, prioritizing embryos based on their implantation potential is crucial for clinical infertility treatment in order to reduce twin pregnancy rate and the time to pregnancy in an IVF center. The AI-powered, random forest prediction model established in this study thus provides a way to improve clinical practice and optimize the chances for people with fertility problems to achieve parenthood. STUDY FUNDING/COMPETING INTERESTS This study was supported by a grant from the National Science and Technology Council, Taiwan (MOST 108-2321-B-006-013 -). There were no competing interests. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- Chun-Wei Chien
- Center for Genomic Medicine, Innovation Headquarters, National Cheng Kung University, Tainan, Taiwan
| | - Yen-An Tang
- Center for Genomic Medicine, Innovation Headquarters, National Cheng Kung University, Tainan, Taiwan
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shuen-Lin Jeng
- Department of Statistics, Institute of Data Science, National Cheng Kung University, Tainan, Taiwan
- Center for Innovative FinTech Business Models, National Cheng Kung University, Tainan, Taiwan
| | - Hsien-An Pan
- IVF center, An-An Women and Children Clinic, Tainan, Taiwan
- Department of Obstetrics and Gynecology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - H Sunny Sun
- Center for Genomic Medicine, Innovation Headquarters, National Cheng Kung University, Tainan, Taiwan
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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7
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Tire B, Ozturk S. Potential effects of assisted reproductive technology on telomere length and telomerase activity in human oocytes and early embryos. J Ovarian Res 2023; 16:130. [PMID: 37400833 DOI: 10.1186/s13048-023-01211-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 06/17/2023] [Indexed: 07/05/2023] Open
Abstract
Telomeres are repetitive DNA sequences at eukaryotic chromosome ends and function in maintaining genome integrity and stability. These unique structures undergo shortening due to various factors including biological aging, consecutive DNA replication, oxidative stress, and genotoxic agents. Shortened telomeres can be lengthened by the enzyme telomerase and alternative lengthening of telomeres in germ cells, early embryos, stem cells, and activated lymphocytes. If telomeres reach to critical length, it may lead to genomic instability, chromosome segregation defects, aneuploidy, and apoptosis. These phenotypes also occur in the oocytes and early embryos, produced using assisted reproductive technologies (ARTs). Thus, a number of studies have examined the potential effects of ART applications such as ovarian stimulation, culture conditions, and cryopreservation procedures on telomeres. Herein, we comprehensively reviewed impacts of these applications on telomere length and telomerase activity in ART-derived oocytes and embryos. Further, we discussed use of these parameters in ART centers as a biomarker in determining oocyte and embryo quality.
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Affiliation(s)
- Betul Tire
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, 07070, Antalya, Turkey
| | - Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, 07070, Antalya, Turkey.
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8
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Wang C, Gu Y, Zhou J, Zang J, Ling X, Li H, Hu L, Xu B, Zhang B, Qin N, Lv H, Duan W, Jiang Y, He Y, Jiang T, Chen C, Han X, Zhou K, Xu B, Liu X, Tao S, Jiang Y, Du J, Dai J, Diao F, Lu C, Guo X, Huo R, Liu J, Lin Y, Xia Y, Jin G, Ma H, Shen H, Hu Z. Leukocyte telomere length in children born following blastocyst-stage embryo transfer. Nat Med 2022; 28:2646-2653. [PMID: 36522605 DOI: 10.1038/s41591-022-02108-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 10/25/2022] [Indexed: 12/23/2022]
Abstract
Perinatal and childhood adverse outcomes associated with assisted reproductive technology (ART) has been reported, but it remains unknown whether the initial leukocyte telomere length (LTL), which is an indicator of age-related phenotypes in later life, is affected. Here, we estimated the LTLs of 1,137 individuals from 365 families, including 202 children conceived by ART and 205 children conceived spontaneously from two centers of the China National Birth Cohort, using whole-genome sequencing (WGS) data. One-year-old children conceived by ART had shorter LTLs than those conceived spontaneously (beta, -0.36; P = 1.29 × 10-3) after adjusting for plurality, sex and other potential confounding factors. In particular, blastocyst-stage embryo transfer was associated with shorter LTL (beta, -0.54, P = 2.69 × 10-3) in children conceived by ART. The association was validated in 586 children conceived by ART from five centers using different LTL quantification methods (that is, WGS or qPCR). Blastocyst-stage embryo transfer resulted in shorter telomere lengths in mice at postnatal day 1 (P = 2.10 × 10-4) and mice at 6 months (P = 0.042). In vitro culturing of mice embryos did not result in shorter telomere lengths in the late cleavage stage, but it did suppress telomerase activity in the early blastocyst stage. Our findings demonstrate the need to evaluate the long-term consequences of ART, particularly for aging-related phenotypes, in children conceived by ART.
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Affiliation(s)
- Cheng Wang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Bioinformatics, School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yayun Gu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jun Zhou
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jie Zang
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiufeng Ling
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Reproduction, The Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, Jiangsu, China
| | - Hong Li
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Reproductive Genetic Center, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, China
| | - Lingmin Hu
- Department of Reproduction, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, Changzhou, Jiangsu, China
| | - Bei Xu
- Reproductive Medicine Center, Tongji Hospital, Tongji Medicine College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Bo Zhang
- Center for Reproductive Medicine, The Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Na Qin
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hong Lv
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,State Key Laboratory of Reproductive Medicine (Suzhou Centre), The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, China
| | - Weiwei Duan
- Department of Bioinformatics, School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yue Jiang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yuanlin He
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Tao Jiang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Biostatistics, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Congcong Chen
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiumei Han
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Kun Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Bo Xu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiaoyu Liu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shiyao Tao
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yangqian Jiang
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jiangbo Du
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Juncheng Dai
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Feiyang Diao
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Clinical Center of Reproductive Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Chuncheng Lu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xuejiang Guo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ran Huo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jiayin Liu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,State Key Laboratory of Reproductive Medicine (Suzhou Centre), The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, China.,Clinical Center of Reproductive Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yuan Lin
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,State Key Laboratory of Reproductive Medicine (Suzhou Centre), The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, China.,Department of Maternal, Child and Adolescent Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yankai Xia
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Guangfu Jin
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China.,State Key Laboratory of Reproductive Medicine (Suzhou Centre), The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, China
| | - Hongxia Ma
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China.,State Key Laboratory of Reproductive Medicine (Suzhou Centre), The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, China
| | - Hongbing Shen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China.,State Key Laboratory of Reproductive Medicine (Suzhou Centre), The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, China
| | - Zhibin Hu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, China. .,Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China. .,State Key Laboratory of Reproductive Medicine (Suzhou Centre), The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, Jiangsu, China.
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9
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Abstract
The number of (TTAGGG)n repeats at the ends of chromosomes is highly variable between individual chromosomes, between different cells and between species. Progressive loss of telomere repeats limits the proliferation of pre-malignant human cells but also contributes to aging by inducing apoptosis and senescence in normal cells. Despite enormous progress in understanding distinct pathways that result in loss and gain of telomeric DNA in different cell types, many questions remain. Further studies are needed to delineate the role of damage to telomeric DNA, replication errors, chromatin structure, liquid-liquid phase transition, telomeric transcripts (TERRA) and secondary DNA structures such as guanine quadruplex structures, R-loops and T-loops in inducing gains and losses of telomere repeats in different cell types. Limitations of current telomere length measurements techniques and differences in telomere biology between species and different cell types complicate generalizations about the role of telomeres in aging and cancer. Here some of the factors regulating the telomere length in embryonic and adult cells in mammals are discussed from a mechanistic and evolutionary perspective.
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Affiliation(s)
- Peter Lansdorp
- Terry Fox Laboratory, British Columbia (BC) Cancer Agency, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Peter Lansdorp,
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10
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Shiraki K, Sato N, Sakai K, Matsumoto S, Kaszynski RH, Takemoto M. Antiviral therapy for COVID-19: Derivation of optimal strategy based on past antiviral and favipiravir experiences. Pharmacol Ther 2022; 235:108121. [PMID: 35121001 PMCID: PMC8806403 DOI: 10.1016/j.pharmthera.2022.108121] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 01/24/2022] [Indexed: 12/22/2022]
Abstract
Favipiravir, a broad-spectrum RNA-dependent RNA polymerase inhibitor, inhibits the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at significantly lower concentrations than the plasma trough levels achieved by the dosage adopted for influenza treatment and exhibits efficacy against coronavirus disease 2019 (COVID-19) pneumonia. Although high doses of favipiravir are required due to the molecule being a purine analog, its conversion into the active form in infected cells with active viral RNA synthesis enhances the antiviral specificity and selectivity as a chain terminator with lethal mutagenesis. Another characteristic feature is the lack of generation of favipiravir-resistant virus. COVID-19 pneumonia is caused by strong cell-mediated immunity against virus-infected cells, and the inflammatory response induced by adaptive immunity continues to peak for 3 to 5 days despite antiviral treatment. This has also been observed in herpes zoster (HZ) and cytomegalovirus (CMV) pneumonia. Inflammation due to an immune response may mask the effectiveness of favipiravir against COVID-19 pneumonia. Favipiravir significantly shortened the recovery time in patients with mild COVID-19 pneumonia by 3 days with the start of treatment by the 5th day of symptom onset. Since both CMV and COVID-19 pneumonia are caused by adaptive immunity and prevention of cytomegalovirus pneumonia is the standard treatment due to difficulties in treating refractory CMV pneumonia, COVID-19 pneumonia should be prevented with early treatment as well. In the present study, we have comprehensively reviewed the optimal antiviral therapy for COVID-19 based on clinical trials of favipiravir for the treatment of COVID-19 pneumonia and the concurrently established therapies for other viral infections, particularly HZ and CMV pneumonia. Optimally, antivirals should be administered immediately after COVID-19 diagnosis, similar to that after influenza diagnosis, to prevent COVID-19 pneumonia and complications resulting from microangiopathy.
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Affiliation(s)
| | - Noriaki Sato
- Department of Biomedical Data Intelligence, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kaoru Sakai
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shirou Matsumoto
- Department of Pediatrics, Graduate School of Medical Sciences, Kumamoto University, Japan
| | - Richard H Kaszynski
- Stanford Solutions, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Masaya Takemoto
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, Japan
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11
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Abstract
PURPOSE OF REVIEW Women's fertility decay starts at the mid 30 s. However, the current delay of childbearing leads to ovarian aging and the need of assisted reproduction technologies (ART). Telomere biology is one of the main pathways involved in organismal aging. Thus, this review will focus on the knowledge acquired during the last 2 years about the telomere pathway and its influence on female fertility and the consequences for the newborn. RECENT FINDINGS New research on telomere biology reaffirms the relationship of telomere attrition and female infertility. Shorter maternal telomeres, which could be aggravated by external factors, underly premature ovarian aging and other complications including preeclampsia, preterm birth and idiopathic pregnancy loss. Finally, the telomere length of the fetus or the newborn is also affected by external factors, such as stress and nutrition. SUMMARY Recent evidence shows that telomeres are implicated in most processes related to female fertility, embryo development and the newborn's health. Thus, telomere length and telomerase activity may be good biomarkers for early detection of ovarian and pregnancy failures, opening the possibility to use telomere therapies to try to solve the infertility situation.
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12
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Phillippe M. Telomeres, oxidative stress, and timing for spontaneous term and preterm labor. Am J Obstet Gynecol 2022; 227:148-162. [PMID: 35460626 DOI: 10.1016/j.ajog.2022.04.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 04/03/2022] [Accepted: 04/12/2022] [Indexed: 11/26/2022]
Abstract
Telomeres are nucleoprotein complexes located at the distal ends of chromosomes. In adults, progressive telomere shortening occurs throughout the lifetime and is thought to contribute to progressive aging, physiological senescence, multiorgan dysfunction, and ultimately, death. As discussed in this review, multiple lines of evidence provide support for the biological plausibility that a telomere-based clock mechanism also determines the length of gestation, leading to the onset of labor (parturition). After telomere expansion at the beginning of pregnancy, the telomere lengths in the gestational tissues (ie, the placenta and fetal membranes) progressively shorten throughout the remainder of pregnancy. The rate of telomere shortening can be accelerated by conditions that affect the mother and result in oxidative stress. Preterm births in the United States are associated with multiple risk factors that are linked with increased oxidative stress. Antioxidant vitamins (ie, vitamins E and C) mitigate the effects of oxidative stress and delay or prevent telomere shortening. Clinical trials with vitamins E and C and with multivitamins started during the periconception period have been associated with reduced rates of preterm births. In the United States, African-American women have a 2-3-fold higher rate of preterm birth. African-American women have multiple risk factors for premature birth, all of which are distinct and potentially additive with regard to epigenetic telomere shortening. The "weathering effect" is the hypothesis to explain the increased rates of chronic illness, disabilities, and early death observed in African-Americans. With regard to pregnancy, accelerated weathering with the associated telomere shortening in the gestational tissues would not only explain the preterm birth disparity but could also explain why highly educated, affluent African-American women continue to have an increased rate of preterm birth. These studies suggest that the racial disparities in preterm birth are potentially mediated by telomere shortening produced by lifetime or even generational exposure to the effects of systemic racism and socioeconomic marginalization. In conclusion, this review presents multiple lines of evidence supporting a novel hypothesis regarding the biological clock mechanism that determines the length of pregnancy, and it opens the possibility of new approaches to prevent or reduce the rate of spontaneous preterm birth.
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13
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Anifandis G, Samara M, Simopoulou M, Messini CI, Chatzimeletiou K, Thodou E, Daponte A, Georgiou I. Insights into the Role of Telomeres in Human Embryological Parameters. Opinions Regarding IVF. J Dev Biol 2021; 9:jdb9040049. [PMID: 34842724 PMCID: PMC8628962 DOI: 10.3390/jdb9040049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 12/30/2022] Open
Abstract
Telomeres promote genome integrity by protecting chromosome ends from the activation of the DNA damage response and protecting chromosomes from the loss of coding sequences due to the end replication problem. Telomere length (TL) is progressively shortened as age progresses, thus resulting in cellular senescence. Therefore, TL is in strong adverse linear correlation with aging. Mounting evidence supports the notion that telomeres and male/female infertility are in a close relationship, posing the biology of telomeres as a hot topic in the era of human-assisted reproduction. Specifically, the length of sperm telomeres is gradually increasing as men get older, while the telomere length of the oocytes seems not to follow similar patterns with that of sperm. Nonetheless, the telomere length of the embryos during the cleavage stages seems to have a paternal origin, but the telomere length can be further extended by telomerase activity during the blastocyst stage. The latter has been proposed as a new molecular biomarker with strong predictive value regarding male infertility. As far as the role of telomeres in assisted reproduction, the data is limited but the length of telomeres in both gametes seems to be affected mainly by the cause of infertility rather than the assisted reproductive therapy (ART) procedure itself. The present review aims to shed more light into the role of telomeres in human embryological parameters, including gametes and embryos and also presents opinions regarding the association between telomeres and in vitro fertilization (IVF).
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Affiliation(s)
- George Anifandis
- Department of Obstetrics and Gynecology, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41222 Larisa, Greece; (C.I.M.); (A.D.)
- Correspondence:
| | - Maria Samara
- Department of Anatomical Pathology, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41222 Larisa, Greece; (M.S.); (E.T.)
| | - Mara Simopoulou
- Laboratory of Physiology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece;
| | - Christina I. Messini
- Department of Obstetrics and Gynecology, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41222 Larisa, Greece; (C.I.M.); (A.D.)
| | - Katerina Chatzimeletiou
- Unit for Human Reproduction, 1st Department of Obstetrics and Gynecology, Faculty of Medicine, School of Health Sciences, Aristotelian University of Thessaloniki, 56403 Thessaloniki, Greece;
| | - Eleni Thodou
- Department of Anatomical Pathology, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41222 Larisa, Greece; (M.S.); (E.T.)
| | - Alexandros Daponte
- Department of Obstetrics and Gynecology, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41222 Larisa, Greece; (C.I.M.); (A.D.)
| | - Ioannis Georgiou
- Laboratory of Medical Genetics, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece;
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14
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Wang F, Chamani IJ, Luo D, Chan K, Navarro PA, Keefe DL. Inhibition of LINE-1 retrotransposition represses telomere reprogramming during mouse 2-cell embryo development. J Assist Reprod Genet 2021; 38:3145-3153. [PMID: 34618297 DOI: 10.1007/s10815-021-02331-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 09/23/2021] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To investigate whether inhibition of LINE-1 affects telomere reprogramming during 2-cell embryo development. METHODS Mouse zygotes were cultured with or without 1 µM azidothymidine (AZT) for up to 15 h (early 2-cell, G1/S) or 24 h (late 2-cell, S/G2). Gene expression and DNA copy number were determined by RT-qPCR and qPCR respectively. Immunostaining and telomeric PNA-FISH were performed for co-localization between telomeres and ZSCAN4 or LINE-1-Orf1p. RESULTS LINE-1 copy number was remarkably reduced in later 2-cell embryos by exposure to 1 µM AZT, and telomere lengths in late 2-cell embryos with AZT were significantly shorter compared to control embryos (P = 0.0002). Additionally, in the absence of LINE-1 inhibition, Dux, Zscan4, and LINE-1 were highly transcribed in early 2-cell embryos, as compared to late 2-cell embryos (P < 0.0001), suggesting that these 2-cell genes are activated at the early 2-cell stage. However, in early 2-cell embryos with AZT treatment, mRNA levels of Dux, Zscan4, and LINE-1 were significantly decreased. Furthermore, both Zscan4 and LINE-1 encoded proteins localized to telomere regions in 2-cell embryos, but this co-localization was dramatically reduced after AZT treatment (P < 0.001). CONCLUSIONS Upon inhibition of LINE-1 retrotransposition in mouse 2-cell embryos, Dux, Zscan4, and LINE-1 were significantly downregulated, and telomere elongation was blocked. ZSCAN4 foci and their co-localization with telomeres were also significantly decreased, indicating that ZSCAN4 is an essential component of the telomere reprogramming that occurs in mice at the 2-cell stage. Our findings also suggest that LINE-1 may directly contribute to telomere reprogramming in addition to regulating gene expression.
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Affiliation(s)
- Fang Wang
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA.
| | - Isaac J Chamani
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Danxia Luo
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Kasey Chan
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Paula Andrea Navarro
- Human Reproduction Division, Department of Gynecology and Obstetrics, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirão Preto, Brazil
| | - David L Keefe
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA
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15
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Anger M, Radonova L, Horakova A, Sekach D, Charousova M. Impact of Global Transcriptional Silencing on Cell Cycle Regulation and Chromosome Segregation in Early Mammalian Embryos. Int J Mol Sci 2021; 22:9073. [PMID: 34445775 PMCID: PMC8396661 DOI: 10.3390/ijms22169073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/14/2021] [Accepted: 08/18/2021] [Indexed: 11/17/2022] Open
Abstract
The onset of an early development is, in mammals, characterized by profound changes of multiple aspects of cellular morphology and behavior. These are including, but not limited to, fertilization and the merging of parental genomes with a subsequent transition from the meiotic into the mitotic cycle, followed by global changes of chromatin epigenetic modifications, a gradual decrease in cell size and the initiation of gene expression from the newly formed embryonic genome. Some of these important, and sometimes also dramatic, changes are executed within the period during which the gene transcription is globally silenced or not progressed, and the regulation of most cellular activities, including those mentioned above, relies on controlled translation. It is known that the blastomeres within an early embryo are prone to chromosome segregation errors, which might, when affecting a significant proportion of a cell within the embryo, compromise its further development. In this review, we discuss how the absence of transcription affects the transition from the oocyte to the embryo and what impact global transcriptional silencing might have on the basic cell cycle and chromosome segregation controlling mechanisms.
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Affiliation(s)
- Martin Anger
- Central European Institute of Technology, Department of Genetics and Reproduction, Veterinary Research Institute, 621 00 Brno, Czech Republic; (L.R.); (A.H.); (D.S.); (M.C.)
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16
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Amirzadegan M, Sadeghi N, Tavalaee M, Nasr-Esfahani MH. Analysis of leukocyte and sperm telomere length in oligozoospermic men. Andrologia 2021; 53:e14204. [PMID: 34369610 DOI: 10.1111/and.14204] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/13/2021] [Accepted: 07/23/2021] [Indexed: 12/15/2022] Open
Abstract
Telomere length is considered one of the most relevant biological markers of genomic stability since it protects DNA from impairment and also ensures chromosome alignment during DNA replication. The negative impact of telomere shortening on sperm quality has been suggested as an important indicator of male infertility. Therefore, we aimed to assess leucocyte and sperm telomere length (LTL&STL), as well as sperm parameters, DNA damage and protamine deficiency in men with oligozoospermia as compared to fertile men. Our results demonstrated a significant reduction in sperm parameters (concentration, motility, morphology), LTL & STL and a significant increase in sperm DNA damage and protamine deficiency in oligozoospermic men compared with fertile individuals. These outcomes revealed that low sperm concentration in men is possibly a sign of impaired meiotic and/or meiotic division during the spermatogenesis process. It is not only associated with proper chromatin packaging but also with telomere length as a key player in the process of mitosis and meiosis, assisting in chromosomal alignment, pairing, synapsis and crossing over during spermatogenesis.
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Affiliation(s)
- Masoumeh Amirzadegan
- Department of Animal Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Niloofar Sadeghi
- Department of Animal Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Marziyeh Tavalaee
- Department of Animal Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Mohammad Hossein Nasr-Esfahani
- Department of Animal Biotechnology, Reproductive Biomedicine Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran.,Isfahan Fertility and Infertility Center, Isfahan, Iran
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17
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Turner KJ, Watson EM, Skinner BM, Griffin DK. Telomere Distribution in Human Sperm Heads and Its Relation to Sperm Nuclear Morphology: A New Marker for Male Factor Infertility? Int J Mol Sci 2021; 22:ijms22147599. [PMID: 34299219 PMCID: PMC8306796 DOI: 10.3390/ijms22147599] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 11/16/2022] Open
Abstract
Infertility is a problem affecting an increasing number of couples worldwide. Currently, marker tests for male factor infertility are complex, highly technical and relatively subjective. Up to 40% of cases of male factor infertility are currently diagnosed as idiopathic therefore, there is a clear need for further research into better ways of diagnosing it. Changes in sperm telomere length have been associated with infertility and closely linked to DNA damage and fragmentation, which are also known to be related to infertility. However, telomere distribution is a parameter thus far underexplored as an infertility marker. Here, we assessed morphological parameters of sperm nuclei in fertile control and male factor infertile cohorts. In addition, we used 2D and 3D fluorescence in situ hybridization (FISH) to compare telomere distribution between these two groups. Our findings indicate that the infertile cohort sperm nuclei were, on average, 2.9% larger in area and showed subtle differences in sperm head height and width. Telomeres were mainly distributed towards the periphery of the nuclei in the control cohort, with diminishing telomere signals towards the center of the nuclei. Sperm nuclei of infertile males, however, had more telomere signals towards the center of the nuclei, a finding supported by 3D imaging. We conclude that, with further development, both morphology and telomere distribution may prove useful investigative tools in the fertility clinic.
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Affiliation(s)
- Kara J. Turner
- School of Biosciences, University of Kent, Giles Lane, Canterbury CT2 7NH, UK;
| | - Eleanor M. Watson
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK; (E.M.W.); (B.M.S.)
| | - Benjamin M. Skinner
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK; (E.M.W.); (B.M.S.)
| | - Darren K. Griffin
- School of Biosciences, University of Kent, Giles Lane, Canterbury CT2 7NH, UK;
- Correspondence:
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18
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Cowell W, Tang D, Yu J, Guo J, Wang S, Baccarelli AA, Perera F, Herbstman JB. Telomere dynamics across the early life course: Findings from a longitudinal study in children. Psychoneuroendocrinology 2021; 129:105270. [PMID: 34020264 PMCID: PMC8217283 DOI: 10.1016/j.psyneuen.2021.105270] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 01/07/2023]
Abstract
Telomeres are protective caps on chromosome ends that shorten with each cell division. Telomere length (TL) predicts the onset of cellular senescence and correlates with longevity and age-related disease risk. Previous research suggests that adults display fixed ranking and tracking of TL by age 20 years, supporting the importance of TL at birth and attrition during childhood. However, longitudinal research examining telomere dynamics during early life is sparse. Here, we used monochrome multiplex quantitative polymerase chain reaction to measure relative TL in leukocytes isolated from cord blood and child blood collected at ages 3, 5, 7, and 9 years among 224 minority children enrolled in a New York City-based birth cohort. We also measured maternal TL at delivery in a subset of 197 participants with a biobanked blood sample. TL decreased most rapidly in the first years of life (birth to 3 years), followed by a period of maintenance into the pre-puberty period. Mothers with longer telomeres gave birth to newborns with longer telomeres that remained longer across childhood, suggesting that the fixed ranking and tracking of TL observed among adults may extend to early childhood or even the prenatal period with a potential transgenerational basis. We did not find significant sex differences in the pattern of child TL change across development. These findings emphasize the need to understand factors and mechanisms that determine TL during early childhood.
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Affiliation(s)
- Whitney Cowell
- Columbia Center for Children's Environmental Health, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA; Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA; Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY 10128, USA.
| | - Deliang Tang
- Columbia Center for Children's Environmental Health, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA; Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Jie Yu
- Columbia Center for Children's Environmental Health, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA; Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Jia Guo
- Columbia Center for Children's Environmental Health, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA; Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Shuang Wang
- Columbia Center for Children's Environmental Health, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA; Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Andrea A Baccarelli
- Columbia Center for Children's Environmental Health, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA; Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Frederica Perera
- Columbia Center for Children's Environmental Health, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA; Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Julie B Herbstman
- Columbia Center for Children's Environmental Health, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA; Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
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19
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Telomere Shortening and Fusions: A Link to Aneuploidy in Early Human Embryo Development. Obstet Gynecol Surv 2021; 76:429-436. [PMID: 34324695 DOI: 10.1097/ogx.0000000000000907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Importance It is known that oocytes undergo aging that is caused by exposure to an aged ovarian microenvironment. Telomere length in mouse and bovine oocytes declines with age, and age-associated telomere shortening in oocytes is considered a sign of poor development competency. Women with advanced age undergoing assisted reproductive technologies have poor outcomes because of increasing aneuploidy rates with age. Research has shown that aneuploidy is associated with DNA damage, reactive oxygen species, and telomere dysfunction. Objective In this review, we focus on the possible relationship between telomere dysfunction and aneuploidy in human early embryo development and several reproductive and perinatal outcomes, discussing the mechanism of aneuploidy caused by telomere shortening and fusion in human embryos. Evidence Acquisition We reviewed the current literature evidence concerning telomere dysfunction and aneuploidy in early human embryo development. Results Shorter telomeres in oocytes, leukocytes, and granulosa cells, related to aging in women, were associated with recurrent miscarriage, trisomy 21, ovarian insufficiency, and decreasing chance of in vitro fertilization success. Telomere length and telomerase activity in embryos have been related to the common genomic instability at the cleavage stage of human development. Complications of assisted reproductive technology pregnancies, such as miscarriage, birth defects, preterm births, and intrauterine growth restriction, also might result from telomere shortening as observed in oocytes, polar body, granulosa cells, and embryos. Conclusions and Relevance Telomere length clearly plays an important role in the development of the embryo and fetus, and the abnormal shortening of telomeres is likely involved in embryo loss during early human development. However, telomere fusion studies have yet to be performed in early human development.
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20
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Vaiserman A, Krasnienkov D. Telomere Length as a Marker of Biological Age: State-of-the-Art, Open Issues, and Future Perspectives. Front Genet 2021; 11:630186. [PMID: 33552142 PMCID: PMC7859450 DOI: 10.3389/fgene.2020.630186] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/21/2020] [Indexed: 12/21/2022] Open
Abstract
Telomere shortening is a well-known hallmark of both cellular senescence and organismal aging. An accelerated rate of telomere attrition is also a common feature of age-related diseases. Therefore, telomere length (TL) has been recognized for a long time as one of the best biomarkers of aging. Recent research findings, however, indicate that TL per se can only allow a rough estimate of aging rate and can hardly be regarded as a clinically important risk marker for age-related pathologies and mortality. Evidence is obtained that other indicators such as certain immune parameters, indices of epigenetic age, etc., could be stronger predictors of the health status and the risk of chronic disease. However, despite these issues and limitations, TL remains to be very informative marker in accessing the biological age when used along with other markers such as indices of homeostatic dysregulation, frailty index, epigenetic clock, etc. This review article is aimed at describing the current state of the art in the field and at discussing recent research findings and divergent viewpoints regarding the usefulness of leukocyte TL for estimating the human biological age.
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Affiliation(s)
- Alexander Vaiserman
- Laboratory of Epigenetics, D.F. Chebotarev Institute of Gerontology, Kyiv, Ukraine
| | - Dmytro Krasnienkov
- Laboratory of Epigenetics, D.F. Chebotarev Institute of Gerontology, Kyiv, Ukraine
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Shorter telomere length of white blood cells is associated with higher rates of aneuploidy among infertile women undergoing in vitro fertilization. Fertil Steril 2020; 115:957-965. [PMID: 33272640 DOI: 10.1016/j.fertnstert.2020.09.164] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/27/2020] [Accepted: 09/30/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To evaluate whether the telomere length of white blood cells (WBC) and cumulus cells (CC) in an infertile population is associated with ovarian and embryonic performance. DESIGN Prospective cohort study. SETTING Academic-affiliated private practice. PATIENTS A total of 175 infertile women undergoing in vitro fertilization (IVF) at a single center between July 2017 and December 2018. INTERVENTIONS On the day of oocyte retrieval, genomic DNA was isolated from WBC and CC samples. Telomere length assessment was performed for both tissue types using quantitative real-time polymerase chain reaction. Telomere lengths were normalized using an AluYa5 sequence as an endogenous control, and linear regressions were applied. MAIN OUTCOME MEASURES This study assessed the relationship between relative telomere length of WBC and CC samples and measures of ovarian and embryonic performance. Specifically, patient age, antimüllerian hormone (AMH) level, peak estradiol (E2) level, number of oocytes retrieved, number of mature (MII) oocytes retrieved, blastulation rate, and aneuploidy rate were assessed. RESULTS There was a statistically significant relationship between WBC relative telomere length and patient age as well as rates of embryonic aneuploidy, with shorter WBC relative telomere length associated with increasing patient age (P<.01) and higher rates of aneuploidy (P=.01). No statistically significant relationships were observed between WBC relative telomere length and the other outcome measures. No significant associations were noted between CC relative telomere length and any outcomes assessed in this study. CONCLUSION The relationship between WBC relative telomere length and aneuploidy warrants further investigation, particularly because significant overlap exists between increasing maternal age and rates of embryonic aneuploidy.
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22
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Uysal F, Kosebent EG, Toru HS, Ozturk S. Decreased expression of TERT and telomeric proteins as human ovaries age may cause telomere shortening. J Assist Reprod Genet 2020; 38:429-441. [PMID: 32856217 DOI: 10.1007/s10815-020-01932-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/18/2020] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE Telomeres are repetitive sequences localized at the ends of eukaryotic chromosomes comprising noncoding DNA and telomere-binding proteins. TRF1 and TRF2 both bind to the double-stranded telomeric DNA to regulate its length throughout the lifespan of eukaryotic cells. POT1 interacts with single-stranded telomeric DNA and contributes to protecting genomic integrity. Previous studies have shown that telomeres gradually shorten as ovaries age, coinciding with fertility loss. However, the molecular background of telomere shortening with ovarian aging is not fully understood. METHODS The present study aimed to determine the spatial and temporal expression levels of the TERT, TRF1, TRF2, and POT1 proteins in different groups of human ovaries: fetal (n = 11), early postnatal (n = 10), premenopausal (n = 12), and postmenopausal (n = 14). Also, the relative telomere signal intensity of each group was measured using the Q-FISH method. RESULTS We found that the telomere signal intensities decreased evenly and significantly from fetal to postmenopausal groups (P < 0.05). The TERT, TRF1, TRF2, and POT1 proteins were localized in the cytoplasmic and nuclear regions of the oocytes, granulosa and stromal cells. Furthermore, the expression levels of these proteins reduced significantly from fetal to postmenopausal groups (P < 0.05). CONCLUSION These findings suggest that decreased TERT and telomere-binding protein expression may underlie the telomere shortening of ovaries with age, which may be associated with female fertility loss. Further investigations are required to elicit the molecular mechanisms regulating the gradual decrease in the expression of TERT and telomere-binding proteins in human oocytes and granulosa cells during ovarian aging.
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Affiliation(s)
- Fatma Uysal
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, 07070, Antalya, Turkey.,Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey
| | - Esra Gozde Kosebent
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, 07070, Antalya, Turkey
| | - Havva Serap Toru
- Department of Pathology, Akdeniz University School of Medicine, Antalya, Turkey
| | - Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, 07070, Antalya, Turkey.
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23
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Lopes AC, Oliveira PF, Pinto S, Almeida C, Pinho MJ, Sá R, Rocha E, Barros A, Sousa M. Discordance between human sperm quality and telomere length following differential gradient separation/swim-up. J Assist Reprod Genet 2020; 37:2581-2603. [PMID: 32767207 DOI: 10.1007/s10815-020-01897-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 07/20/2020] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Strong evidence has suggested an important role of telomeres in meiosis, fertilization, and embryo development. PURPOSE To determine if sperm telomere length (STL) in sperm purified by differential gradient centrifugation followed by swim-up (selected STL) is correlated with sperm quality and clinical outcomes. METHODS Relative selected STL was assessed by quantitative polymerase chain reaction (Q-PCR) in 78 consecutive assisted reproductive technology (ART) treatments during 2017. Statistical analyses were performed in the totality of patients, and in normozoospermic and non-normozoospermic patients. These included correlations between selected STL and sperm quality parameters, embryological parameters (multivariable linear regression), and clinical parameters (multivariable logistic regression). RESULTS No significant correlations were found between selected STL and sperm quality in the total population. However, selected STL was significantly correlated with total sperm count (r = 0.361; P = 0.039) and sperm DNA fragmentation-post-acrosomal region pattern (r = - 0.464; P = 0.030) in normozoospermic patients. No relation was observed between selected STL and clinical outcomes in any clinical group. CONCLUSIONS As the correlations observed in normozoospermic patients were not representative of the whole heterogeneous population, differences in the sperm characteristics of the study population may lead to discrepant results when evaluating the association of STL with sperm quality. Since the total population selected STL was not related with sperm quality and with clinical outcomes, results do not support the use of selected STL measurement to evaluate the reproductive potential of the male patient or to predict the success rates of ART treatments.
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Affiliation(s)
- Ana Catarina Lopes
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.,Department of Life Sciences, Faculty of Science and Technology, New University of Lisbon, Campus Caparica, 2829-516, Caparica, Portugal
| | - Pedro Fontes Oliveira
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.,Department of Genetics, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal.,Institute of Research and Innovation in Health, University of Porto, 4200-135, Porto, Portugal
| | - Soraia Pinto
- Centre for Reproductive Genetics Prof. Alberto Barros, 4100-009, Porto, Portugal
| | - Carolina Almeida
- Department of Genetics, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal
| | - Maria João Pinho
- Department of Genetics, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal
| | - Rosália Sá
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.,Multidisciplinary Unit for Biomedical Research, Institute of Biomedical Sciences Abel Salazar, University of Porto, 4050-313, Porto, Portugal
| | - Eduardo Rocha
- Laboratory of Histology and Embryology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar, University of Porto, 4050-313, Porto, Portugal
| | - Alberto Barros
- Department of Genetics, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal.,Institute of Research and Innovation in Health, University of Porto, 4200-135, Porto, Portugal.,Centre for Reproductive Genetics Prof. Alberto Barros, 4100-009, Porto, Portugal
| | - Mário Sousa
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal. .,Multidisciplinary Unit for Biomedical Research, Institute of Biomedical Sciences Abel Salazar, University of Porto, 4050-313, Porto, Portugal.
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24
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Jodar M, Attardo-Parrinello C, Soler-Ventura A, Barrachina F, Delgado-Dueñas D, Cívico S, Calafell JM, Ballescà JL, Oliva R. Sperm proteomic changes associated with early embryo quality after ICSI. Reprod Biomed Online 2020; 40:700-710. [DOI: 10.1016/j.rbmo.2020.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 10/31/2019] [Accepted: 01/06/2020] [Indexed: 12/11/2022]
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25
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Rocca MS, Foresta C, Ferlin A. Telomere length: lights and shadows on their role in human reproduction. Biol Reprod 2020; 100:305-317. [PMID: 30277496 DOI: 10.1093/biolre/ioy208] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 09/19/2018] [Accepted: 09/28/2018] [Indexed: 12/13/2022] Open
Abstract
Telomeres are repeated DNA sequences whose main function is to preserve genome stability, protecting chromosomes ends from shortening caused by progressive loss during each cell replication or DNA damage. Telomere length regulation is normally achieved by telomerase enzyme, whose activity is progressively shut off during embryonic differentiation in somatic tissues, whereas it is maintained in germ cells, activated lymphocytes, and certain types of stem cell populations. The maintenance of telomerase activity for a longer time is necessary for germ cells to delay telomere erosion, thus avoiding chromosome segregation defects that could contribute to aneuploid or unbalanced gametes. Over the last few years, telomere biology has become an important topic in the field of human reproduction, encouraging several studies to focus on the relation between telomere length and spermatogenesis and male fertility, embryo development and quality during assisted reproductive treatment, and female pathologies as polycystic ovary, premature ovarian insufficiency, and endometriosis. This review analyzes whether telomere length in germ cells is related to reproduction fitness, whether telomere length is related to pathologies associated with male and female fertility, and whether measurement of telomere length could represent a biomarker of germ cell and embryo quality. Telomere length could be considered a molecular marker of spermatogenesis and sperm quality and is somewhat related to male fertility potential. Fewer evidence, although promising, is available for oocytes, female (in)fertility, and embryo quality. The increasing evidence for a role of telomeres and telomere length in human reproduction, indeed, has expanded the historical view of considering them just a marker of aging. Telomere length might have in the future a prognostic potential in couple infertility, especially useful to select best germ cells with the greatest potential of fertilization.
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Affiliation(s)
- Maria Santa Rocca
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padova, Italy
| | - Carlo Foresta
- Department of Medicine, Unit of Andrology and Reproductive Medicine, University of Padova, Padova, Italy
| | - Alberto Ferlin
- Department of Clinical and Experimental Sciences, Unit of Endocrinology, University of Brescia, Brescia, Italy
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26
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Turner K, Lynch C, Rouse H, Vasu V, Griffin DK. Direct Single-Cell Analysis of Human Polar Bodies and Cleavage-Stage Embryos Reveals No Evidence of the Telomere Theory of Reproductive Ageing in Relation to Aneuploidy Generation. Cells 2019; 8:E163. [PMID: 30781491 PMCID: PMC6406255 DOI: 10.3390/cells8020163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/28/2019] [Accepted: 02/13/2019] [Indexed: 01/18/2023] Open
Abstract
Reproductive ageing in women, particularly after the age of 35, is associated with an exponential increase in the proportion of chromosomally abnormal oocytes produced. Several hypotheses have attempted to explain this observation, including the 'limited oocyte pool' hypothesis and the 'two-hit' hypothesis, the latter explaining that a depletion in oocyte quality with age results from the multiple opportune stages for errors to occur in meiosis. Recently however, the telomere theory of reproductive ageing in women has been proposed. This suggests that shortened telomeres in oocytes of women of advanced maternal age render oocytes unable to support fertilization and embryogenesis. Despite a credible rationale for the telomere theory of reproductive ageing in women, very few studies have assessed telomere length directly in human oocytes or preimplantation embryos. Therefore, we directly assessed relative telomere length in first polar bodies and blastomeres from cleavage stage (day 3) embryos. In both cell types we tested the hypothesis that (1) older women have shorter telomeres and (2) chromosomally abnormal (aneuploid) gametes/embryos have shorter telomeres. In all cases, we found no evidence of altered telomere length associated with age-related aneuploidy.
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Affiliation(s)
- Kara Turner
- School of Biosciences, University of Kent, Giles Lane, Canterbury CT2 7NJ, UK.
| | - Colleen Lynch
- Cooper Genomics Nottingham, Medicity, D6 Building, Thane Road, Nottingham NG90 6BH, UK.
| | - Hannah Rouse
- Cooper Genomics Nottingham, Medicity, D6 Building, Thane Road, Nottingham NG90 6BH, UK.
| | - Vimal Vasu
- School of Biosciences, University of Kent, Giles Lane, Canterbury CT2 7NJ, UK.
- Department of Child Health, East Kent Hospitals University Foundation NHS Trust, William Harvey Hospital, Ashford TN24 0LZ, UK.
| | - Darren K Griffin
- School of Biosciences, University of Kent, Giles Lane, Canterbury CT2 7NJ, UK.
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27
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Turner KJ, Vasu V, Griffin DK. Telomere Biology and Human Phenotype. Cells 2019; 8:cells8010073. [PMID: 30669451 PMCID: PMC6356320 DOI: 10.3390/cells8010073] [Citation(s) in RCA: 199] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 01/14/2019] [Accepted: 01/16/2019] [Indexed: 12/15/2022] Open
Abstract
Telomeres are nucleoprotein structures that cap the end of each chromosome arm and function to maintain genome stability. The length of telomeres is known to shorten with each cell division and it is well-established that telomere attrition is related to replicative capacity in vitro. Moreover, telomere loss is also correlated with the process of aging in vivo. In this review, we discuss the mechanisms that lead to telomere shortening and summarise telomere homeostasis in humans throughout a lifetime. In addition, we discuss the available evidence that shows that telomere shortening is related to human aging and the onset of age-related disease.
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Affiliation(s)
- Kara J Turner
- University of Kent, School of Biosciences, Giles Lane, Canterbury, Kent, CT2-7NJ, UK.
| | - Vimal Vasu
- University of Kent, School of Biosciences, Giles Lane, Canterbury, Kent, CT2-7NJ, UK.
- Department of Child Health, East Kent Hospitals University Foundation NHS Trust, William Harvey Hospital, Ashford, Kent, TN24-0LZ, UK.
| | - Darren K Griffin
- University of Kent, School of Biosciences, Giles Lane, Canterbury, Kent, CT2-7NJ, UK.
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28
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Pirzada RH, Orun O, Erzik C, Cagsin H, Serakinci N. Role of TRF2 and TPP1 regulation in idiopathic recurrent pregnancy loss. Int J Biol Macromol 2019; 127:306-310. [PMID: 30611803 DOI: 10.1016/j.ijbiomac.2019.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 12/31/2018] [Accepted: 01/03/2019] [Indexed: 12/31/2022]
Abstract
Telomeres are the tandem repeats (TTAGGG) present at the ends of the chromosomes that ensure chromosome stability and protect chromosomes from degradation. Telomeres in somatic human cells shorten after every cellular division and are linked to the cellular senescence. In this study we have investigated telomere length and expression of shelterin genes in aborted fetus material from idiopathic recurrent pregnancy losses. Telomere length was measured using Telomere Restriction Fragment Length (TRF) analysis. The gene expression levels for important shelterin complex proteins (TRF1, TRF2, POT1, and TPP1) were determined by Real-time Quantitative Reverse Transcriptase PCR (qRT-PCR). Our results demonstrated down regulation of TRF2 and TPP1 and a strong decline in average telomere length in abort material from women suffering from idiopathic recurrent pregnancy loss. We suggest that shorter telomere length and downregulation of the major shelterin components TRF2 and TPP1 leading to "telomere uncapping", might play a critical role in recurrent pregnancy loss.
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Affiliation(s)
- Rameez Hassan Pirzada
- Near East University, Faculty of Medicine, Department of Medical Genetics, 999058 Nicosia, North Cyprus, Turkey; Institute of Molecular Biology and Biotechnology, The University of Lahore, New Campus, Lahore 55150, Pakistan
| | - Oya Orun
- Marmara University School of Medicine, Biophysics Department, Istanbul, Turkey
| | - Can Erzik
- Marmara University School of Medicine, Department of Medical Biology, Istanbul, Turkey
| | - Huseyin Cagsin
- Near East University, Faculty of Medicine, Department of Medical Genetics, 999058 Nicosia, North Cyprus, Turkey; Near East University, Faculty of Art and Sciences, Department of Molecular Biology and Genetics, 999058 Nicosia, North Cyprus, Turkey
| | - Nedime Serakinci
- Near East University, Faculty of Medicine, Department of Medical Genetics, 999058 Nicosia, North Cyprus, Turkey; Near East University, Faculty of Art and Sciences, Department of Molecular Biology and Genetics, 999058 Nicosia, North Cyprus, Turkey.
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29
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Arias-Sosa LA. Understanding the Role of Telomere Dynamics in Normal and Dysfunctional Human Reproduction. Reprod Sci 2018; 26:6-17. [DOI: 10.1177/1933719118804409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Luis Alejandro Arias-Sosa
- Universidad Pedagógica y Tecnológica de Colombia, School of Biological Science, Tunja, Boyacá, Colombia
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30
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Lopes AC, Oliveira PF, Sousa M. Shedding light into the relevance of telomeres in human reproduction and male factor infertility†. Biol Reprod 2018; 100:318-330. [DOI: 10.1093/biolre/ioy215] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/05/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Ana Catarina Lopes
- Laboratory of Cell Biology, Department of Microscopy, and Multidisciplinary Unit for Biomedical Research (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, New University of Lisbon (FCT-UNL), Campus Caparica, Caparica, Portugal
| | - Pedro F Oliveira
- Laboratory of Cell Biology, Department of Microscopy, and Multidisciplinary Unit for Biomedical Research (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- Department of Genetics, Faculty of Medicine, University of Porto, Porto, Portugal
- i3S- Institute of Research and Innovation in Health, University of Porto, Porto, Portugal
| | - Mário Sousa
- Laboratory of Cell Biology, Department of Microscopy, and Multidisciplinary Unit for Biomedical Research (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- Centre for Reproductive Genetics Professor Alberto Barros, Porto, Portugal
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31
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Kosebent EG, Uysal F, Ozturk S. Telomere length and telomerase activity during folliculogenesis in mammals. J Reprod Dev 2018; 64:477-484. [PMID: 30270279 PMCID: PMC6305847 DOI: 10.1262/jrd.2018-076] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Telomeres are repetitive non-coding DNA sequences located at the ends of chromosomes in eukaryotic cells. Their most important function is to protect chromosome ends from being recognized
as DNA damage. They are also implicated in meiosis and synapse formation. The length of telomeres inevitably shortens at the end of each round of DNA replication and, also, as a consequence
of the exposure to oxidative stress and/or genotoxic agents. The enzyme telomerase contributes to telomere lengthening. It has been reported that telomerase is exclusively expressed in germ
cells, granulosa cells, early embryos, stem cells, and various types of cancerous cells. Granulosa cells undergo many mitotic divisions and either granulosa cells or oocytes are exposed to a
variety of genotoxic agents throughout folliculogenesis; thus, telomerase plays an important role in the maintenance of telomere length. In this review article, we have comprehensively
evaluated the studies focusing on the regulation of telomerase expression and activity, as well as telomere length, during folliculogenesis from primordial to antral follicles, in several
mammalian species including mice, bovines, and humans. Also, the possible relationships between female infertility caused by follicular development defects and alterations in the telomeres
and/or telomerase activity are discussed.
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Affiliation(s)
- Esra Gozde Kosebent
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya 07070, Turkey
| | - Fatma Uysal
- Department of Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey
| | - Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya 07070, Turkey
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Abstract
Life starts with a zygote, which is formed by the fusion of a haploid sperm and egg. The formation of a blastomere by cleavage division (nuclear division without an increase in cell size) is the first step in embryogenesis, after the formation of the zygote. Blastomeres are responsible for reprogramming the parental genome as a new embryonic genome for generation of the pluripotent stem cells which then differentiate by Waddington's epigenetic landscape to create a new life. Multiple authors over the past 150 years have proposed that tumors arises from development gone awry at a point within Waddington's landscape. Recent discoveries showing that differentiated somatic cells can be reprogrammed into induced pluripotent stem cells, and that somatic cell nuclear transfer can be used to successfully clone animals, have fundamentally reshaped our understanding of tumor development and origin. Differentiated somatic cells are plastic and can be induced to dedifferentiate into pluripotent stem cells. Here, I review the evidence that suggests somatic cells may have a previously overlooked endogenous embryonic program that can be activated to dedifferentiate somatic cells into stem cells of various potencies for tumor initiation. Polyploid giant cancer cells (PGCCs) have long been observed in cancer and were thought originally to be nondividing. Contrary to this belief, recent findings show that stress-induced PGCCs divide by endoreplication, which may recapitulate the pattern of cleavage-like division in blastomeres and lead to dedifferentiation of somatic cells by a programmed process known as "the giant cell cycle", which comprise four distinct but overlapping phases: initiation, self-renewal, termination and stability. Depending on the intensity and type of stress, different levels of dedifferentiation result in the formation of tumors of different grades of malignancy. Based on these results, I propose a unified dualistic model to demonstrate the origin of human tumors. The tenet of this model includes four points, as follows. 1. Tumors originate from a stem cell at a specific developmental hierarchy, which can be achieved by dualistic origin: dedifferentiation of the zygote formed by two haploid gametes (sexual reproduction) via the blastomere during normal development, or transformation from damaged or aged mature somatic cells via a blastomere-like embryonic program (asexual reproduction). 2. Initiation of the tumor begins with a stem cell that has uncoupled the differentiation from the proliferation program which results in stem cell maturation arrest. 3. The developmental hierarchy at which stem cells arrest determines the degree of malignancy: the more primitive the level at which stem cells arrest, the greater the likelihood of the tumor being malignant. 4. Environmental factors and intrinsic genetic or epigenetic alterations represent the risk factors or stressors that facilitate stem cell arrest and somatic cell dedifferentiation. However, they, per se, are not the driving force of tumorigenesis. Thus, the birth of a tumor can be viewed as a triad that originates from a stem cell via dedifferentiation through a blastomere or blastomere-like program, which then differentiates along Waddington's landscape, and arrests at a developmental hierarchy. Blocking the PGCC-mediated dedifferentiation process and inducing their differentiation may represent a novel alternative approach to eliminate the tumor occurrence and therapeutic resistance.
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Dynamics of Telomere Length and Telomerase Activity in the Human Fetal Liver at 5-12 Weeks of Gestation. Stem Cells Int 2018; 2018:1385903. [PMID: 30057621 PMCID: PMC6051073 DOI: 10.1155/2018/1385903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 06/12/2018] [Indexed: 12/12/2022] Open
Abstract
Fetal stem cell- (FSC-) based therapy is a promising treatment option for many diseases. The differentiation potential of FSCs is greater than that in adult stem cells, and they are more tissue-specific and have lower immunogenicity and better intrinsic homing than embryonic ones. Embryonic stem cells have higher proliferative potential than FSCs but can cause teratomas. Therefore, an evaluation of this potential represents an important biomedical challenge. Since regulation of telomere length (TL) is one mechanism governing cellular proliferation, TL is a useful surrogate marker for cell replicative potential. The prenatal dynamics of TL, however, has never been comprehensively studied. In the present study, dynamics of TL and telomerase activity in the human fetal liver during 5–12 weeks of gestation is examined. Both TL and telomerase activity were positively correlated with week of gestation. For both parameters studied, the trend to increase was evident up to 10th week of gestation. After that, they reached a plateau and remained stable. These findings indicate that telomerase activity remains high during the fetal stage, suggesting high replicative capacity of FSCs and their considerable potential for transplantation therapies. These findings, however, are preliminary only due to small sample size and require further evaluation.
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Armstrong CA, Tomita K. Fundamental mechanisms of telomerase action in yeasts and mammals: understanding telomeres and telomerase in cancer cells. Open Biol 2018; 7:rsob.160338. [PMID: 28330934 PMCID: PMC5376709 DOI: 10.1098/rsob.160338] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/20/2017] [Indexed: 12/12/2022] Open
Abstract
Aberrant activation of telomerase occurs in 85–90% of all cancers and underpins the ability of cancer cells to bypass their proliferative limit, rendering them immortal. The activity of telomerase is tightly controlled at multiple levels, from transcriptional regulation of the telomerase components to holoenzyme biogenesis and recruitment to the telomere, and finally activation and processivity. However, studies using cancer cell lines and other model systems have begun to reveal features of telomeres and telomerase that are unique to cancer. This review summarizes our current knowledge on the mechanisms of telomerase recruitment and activation using insights from studies in mammals and budding and fission yeasts. Finally, we discuss the differences in telomere homeostasis between normal cells and cancer cells, which may provide a foundation for telomere/telomerase targeted cancer treatments.
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Affiliation(s)
- Christine A Armstrong
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Kazunori Tomita
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
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35
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Huleyuk N, Tkach I, Zastavna D, Tyrka M. Can telomere shortening be the main indicator of non-viable fetus elimination? Mol Cytogenet 2018; 11:11. [PMID: 29416566 PMCID: PMC5785879 DOI: 10.1186/s13039-018-0361-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 01/18/2018] [Indexed: 01/29/2023] Open
Abstract
Background Telomeres are transcriptionally inactive genomic areas, which, if shortened, are associated with pathological processes, unsuccessful fertilization, aging, and death. Telomere dysfunction has also been linked to chromosomal rearrangements and genomic instability. The role of telomeres in postnatal life has been extensively studied and discussed both in physiological as well as in pathological processes. However, the role of telomere length in prenatal development is still poorly understood, and mainly concerns the preimplantation stage. The aim of this study was to estimate relative telomere length in spontaneously eliminated human embryos between 5th and 12th week of gestation. Results Relative telomere length was measured from total genomic DNA using a real-time polymerase chain reaction approach. In this study, we examined relative telomere length in 80 spontaneously eliminated embryos and in 25 embryos eliminated due to induced abortions. Relative telomere length in spontaneous abortions was significantly lower (P = 0.000001) compared to the induced abortions. Spontaneous abortions with aneuploid anomalies (monosomy X, trisomy 21, trisomy 16 and triploidy) were characterized by shorter telomeres, compared to spontaneous abortions, subgroup with euploid (46,XN) karyotype. Conclusion Spontaneously lost pregnancies are characterized by shortened telomeres, especially in embryos with aneuploidies. We hypothesize that the shortening of telomeres is involved in the processes leading to spontaneous abortions.
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Affiliation(s)
- Nataliya Huleyuk
- 1Institute of Hereditary Pathology, NAMS of Ukraine, Lysenko Str. 31a, Lviv, 79008 Ukraine
| | - Iryna Tkach
- 1Institute of Hereditary Pathology, NAMS of Ukraine, Lysenko Str. 31a, Lviv, 79008 Ukraine
| | - Danuta Zastavna
- 1Institute of Hereditary Pathology, NAMS of Ukraine, Lysenko Str. 31a, Lviv, 79008 Ukraine.,2Department of Biotechnology and Bioinformatics, Faculty of Chemistry, Rzeszow University of Technology, Al. Powstańców Warszawy 6, 35-959 Rzeszow, Poland
| | - Miroslaw Tyrka
- 2Department of Biotechnology and Bioinformatics, Faculty of Chemistry, Rzeszow University of Technology, Al. Powstańców Warszawy 6, 35-959 Rzeszow, Poland
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Greaney J, Wei Z, Homer H. Regulation of chromosome segregation in oocytes and the cellular basis for female meiotic errors. Hum Reprod Update 2017; 24:135-161. [PMID: 29244163 DOI: 10.1093/humupd/dmx035] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 09/12/2017] [Accepted: 11/26/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Meiotic chromosome segregation in human oocytes is notoriously error-prone, especially with ageing. Such errors markedly reduce the reproductive chances of increasing numbers of women embarking on pregnancy later in life. However, understanding the basis for these errors is hampered by limited access to human oocytes. OBJECTIVE AND RATIONALE Important new discoveries have arisen from molecular analyses of human female recombination and aneuploidy along with high-resolution analyses of human oocyte maturation and mouse models. Here, we review these findings to provide a contemporary picture of the key players choreographing chromosome segregation in mammalian oocytes and the cellular basis for errors. SEARCH METHODS A search of PubMed was conducted using keywords including meiosis, oocytes, recombination, cohesion, cohesin complex, chromosome segregation, kinetochores, spindle, aneuploidy, meiotic cell cycle, spindle assembly checkpoint, anaphase-promoting complex, DNA damage, telomeres, mitochondria, female ageing and female fertility. We extracted papers focusing on mouse and human oocytes that best aligned with the themes of this review and that reported transformative and novel discoveries. OUTCOMES Meiosis incorporates two sequential rounds of chromosome segregation executed by a spindle whose component microtubules bind chromosomes via kinetochores. Cohesion mediated by the cohesin complex holds chromosomes together and should be resolved at the appropriate time, in a specific step-wise manner and in conjunction with meiotically programmed kinetochore behaviour. In women, the stage is set for meiotic error even before birth when female-specific crossover maturation inefficiency leads to the formation of at-risk recombination patterns. In adult life, multiple co-conspiring factors interact with at-risk crossovers to increase the likelihood of mis-segregation. Available evidence support that these factors include, but are not limited to, cohesion deterioration, uncoordinated sister kinetochore behaviour, erroneous microtubule attachments, spindle instability and structural chromosomal defects that impact centromeres and telomeres. Data from mice indicate that cohesin and centromere-specific histones are long-lived proteins in oocytes. Since these proteins are pivotal for chromosome segregation, but lack any obvious renewal pathway, their deterioration with age provides an appealing explanation for at least some of the problems in older oocytes. WIDER IMPLICATIONS Research in the mouse model has identified a number of candidate genes and pathways that are important for chromosome segregation in this species. However, many of these have not yet been investigated in human oocytes so it is uncertain at this stage to what extent they apply to women. The challenge for the future involves applying emerging knowledge of female meiotic molecular regulation towards improving clinical fertility management.
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Affiliation(s)
- Jessica Greaney
- Christopher Chen Oocyte Biology Research Laboratory, Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Royal Brisbane & Women's Hospital Campus, Herston QLD 4029, Australia
| | - Zhe Wei
- Christopher Chen Oocyte Biology Research Laboratory, Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Royal Brisbane & Women's Hospital Campus, Herston QLD 4029, Australia
| | - Hayden Homer
- Christopher Chen Oocyte Biology Research Laboratory, Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Royal Brisbane & Women's Hospital Campus, Herston QLD 4029, Australia
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Oblette A, Rives N, Dumont L, Rives A, Verhaeghe F, Jumeau F, Rondanino C. Assessment of sperm nuclear quality after in vitro maturation of fresh or frozen/thawed mouse pre-pubertal testes. Mol Hum Reprod 2017; 23:674-684. [DOI: 10.1093/molehr/gax048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 08/17/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- A Oblette
- Normandie Univ, UNIROUEN, EA 4308 ‘Gametogenesis and Gamete Quality’, Rouen University Hospital, Department of Reproductive Biology—CECOS, F 76000 Rouen, France
| | - N Rives
- Normandie Univ, UNIROUEN, EA 4308 ‘Gametogenesis and Gamete Quality’, Rouen University Hospital, Department of Reproductive Biology—CECOS, F 76000 Rouen, France
| | - L Dumont
- Normandie Univ, UNIROUEN, EA 4308 ‘Gametogenesis and Gamete Quality’, Rouen University Hospital, Department of Reproductive Biology—CECOS, F 76000 Rouen, France
| | - A Rives
- Normandie Univ, UNIROUEN, EA 4308 ‘Gametogenesis and Gamete Quality’, Rouen University Hospital, Department of Reproductive Biology—CECOS, F 76000 Rouen, France
| | - F Verhaeghe
- Normandie Univ, UNIROUEN, EA 4308 ‘Gametogenesis and Gamete Quality’, Rouen University Hospital, Department of Reproductive Biology—CECOS, F 76000 Rouen, France
| | - F Jumeau
- Normandie Univ, UNIROUEN, EA 4308 ‘Gametogenesis and Gamete Quality’, Rouen University Hospital, Department of Reproductive Biology—CECOS, F 76000 Rouen, France
| | - C Rondanino
- Normandie Univ, UNIROUEN, EA 4308 ‘Gametogenesis and Gamete Quality’, Rouen University Hospital, Department of Reproductive Biology—CECOS, F 76000 Rouen, France
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Capalbo A, Hoffmann ER, Cimadomo D, Maria Ubaldi F, Rienzi L. Human female meiosis revised: new insights into the mechanisms of chromosome segregation and aneuploidies from advanced genomics and time-lapse imaging. Hum Reprod Update 2017; 23:706-722. [DOI: 10.1093/humupd/dmx026] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 08/11/2017] [Indexed: 12/14/2022] Open
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Zou Y, Tong HJ, Li M, Tan KS, Cao T. Telomere length is regulated by FGF-2 in human embryonic stem cells and affects the life span of its differentiated progenies. Biogerontology 2016; 18:69-84. [DOI: 10.1007/s10522-016-9662-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Accepted: 10/13/2016] [Indexed: 12/20/2022]
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Teichroeb JH, Kim J, Betts DH. The role of telomeres and telomerase reverse transcriptase isoforms in pluripotency induction and maintenance. RNA Biol 2016; 13:707-19. [PMID: 26786236 DOI: 10.1080/15476286.2015.1134413] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Telomeres are linear guanine-rich DNA structures at the ends of chromosomes. The length of telomeric DNA is actively regulated by a number of mechanisms in highly proliferative cells such as germ cells, cancer cells, and pluripotent stem cells. Telomeric DNA is synthesized by way of the ribonucleoprotein called telomerase containing a reverse transcriptase (TERT) subunit and RNA component (TERC). TERT is highly conserved across species and ubiquitously present in their respective pluripotent cells. Recent studies have uncovered intricate associations between telomeres and the self-renewal and differentiation properties of pluripotent stem cells. Interestingly, the past decade's work indicates that the TERT subunit also has the capacity to modulate mitochondrial function, to remodel chromatin structure, and to participate in key signaling pathways such as the Wnt/β-catenin pathway. Many of these non-canonical functions do not require TERT's catalytic activity, which hints at possible functions for the extensive number of alternatively spliced TERT isoforms that are highly expressed in pluripotent stem cells. In this review, some of the established and potential routes of pluripotency induction and maintenance are highlighted from the perspectives of telomere maintenance, known TERT isoform functions and their complex regulation.
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Affiliation(s)
- Jonathan H Teichroeb
- a Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry , The University of Western Ontario , London , Ontario , Canada
| | - Joohwan Kim
- a Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry , The University of Western Ontario , London , Ontario , Canada
| | - Dean H Betts
- a Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry , The University of Western Ontario , London , Ontario , Canada.,b Children's Health Research Institute, Lawson Health Research Institute , London , Ontario , Canada
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Larrivée-Vanier S, Magne F, Patey N, Chanoine JP, Vuissoz JM, Van Vliet G, Deladoëy J. Conserved Telomere Length in Human Ectopic Thyroids: An Argument Against Premature Differentiation Causing Arrested Migration. Thyroid 2015; 25:1050-4. [PMID: 26131731 PMCID: PMC4746059 DOI: 10.1089/thy.2015.0204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND In humans, the cause of arrested migration of the median thyroid anlage resulting in an ectopic sublingual gland is unknown. These ectopic glands have a normal follicular architecture but their thyrotropin-induced growth is insufficient, leading to congenital hypothyroidism in the vast majority of affected subjects. We hypothesized that arrested migration is due to premature differentiation [reflected by decreased telomere length (TL)], as observed in neural tube defects in mice. METHODS Absolute TL and telomerase reverse transcriptase (hTERT) expression was measured in four ectopic and six orthotopic thyroids. TL was measured by quantitative polymerase chain reaction of genomic DNA, whereas hTERT expression was measured by quantitative polymerase chain reaction of total RNA. RESULTS The mean±standard deviation TL (in kilobases per diploid genome) was 140.45±40.07 in ectopic and 97.50±30.48 in orthotopic thyroids (p=0.12). Expression of hTERT was quiescent in both ectopic and orthotopic thyroids. CONCLUSIONS Compared with orthotopic thyroids, TL shortening is not observed in ectopic thyroid tissues and, consequently, no compensatory hTERT expression was measured. This makes premature differentiation an unlikely cause of arrested migration and it suggests, indirectly, that ectopic thyroids are not at higher risk of cancer than orthotopic thyroids.
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Affiliation(s)
- Stéphanie Larrivée-Vanier
- Endocrinology Service and Research Center, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Canada
- Department of Pediatrics, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Canada
| | - Fabien Magne
- Endocrinology Service and Research Center, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Canada
- Department of Pediatrics, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Canada
| | - Natalie Patey
- Department of Pathology, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Canada
| | - Jean-Pierre Chanoine
- Endocrinology and Diabetes Unit, Department of Pediatrics, British Columbia Children’s Hospital, University of British Columbia, Vancouver, Canada
| | - Jean-Marc Vuissoz
- Division of Pediatric Endocrinology, University Children’s Hospital Basel (UKBB), University of Basel, Basel, Switzerland
| | - Guy Van Vliet
- Endocrinology Service and Research Center, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Canada
- Department of Pediatrics, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Canada
| | - Johnny Deladoëy
- Endocrinology Service and Research Center, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Canada
- Department of Pediatrics, Centre Hospitalier Universitaire Sainte-Justine, University of Montreal, Montreal, Canada
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Hasegawa Y, Taylor D, Ovchinnikov DA, Wolvetang EJ, de Torrenté L, Mar JC. Variability of Gene Expression Identifies Transcriptional Regulators of Early Human Embryonic Development. PLoS Genet 2015; 11:e1005428. [PMID: 26288249 PMCID: PMC4546122 DOI: 10.1371/journal.pgen.1005428] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 07/06/2015] [Indexed: 11/18/2022] Open
Abstract
An analysis of gene expression variability can provide an insightful window into how regulatory control is distributed across the transcriptome. In a single cell analysis, the inter-cellular variability of gene expression measures the consistency of transcript copy numbers observed between cells in the same population. Application of these ideas to the study of early human embryonic development may reveal important insights into the transcriptional programs controlling this process, based on which components are most tightly regulated. Using a published single cell RNA-seq data set of human embryos collected at four-cell, eight-cell, morula and blastocyst stages, we identified genes with the most stable, invariant expression across all four developmental stages. Stably-expressed genes were found to be enriched for those sharing indispensable features, including essentiality, haploinsufficiency, and ubiquitous expression. The stable genes were less likely to be associated with loss-of-function variant genes or human recessive disease genes affected by a DNA copy number variant deletion, suggesting that stable genes have a functional impact on the regulation of some of the basic cellular processes. Genes with low expression variability at early stages of development are involved in regulation of DNA methylation, responses to hypoxia and telomerase activity, whereas by the blastocyst stage, low-variability genes are enriched for metabolic processes as well as telomerase signaling. Based on changes in expression variability, we identified a putative set of gene expression markers of morulae and blastocyst stages. Experimental validation of a blastocyst-expressed variability marker demonstrated that HDDC2 plays a role in the maintenance of pluripotency in human ES and iPS cells. Collectively our analyses identified new regulators involved in human embryonic development that would have otherwise been missed using methods that focus on assessment of the average expression levels; in doing so, we highlight the value of studying expression variability for single cell RNA-seq data.
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Affiliation(s)
- Yu Hasegawa
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America; Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Deanne Taylor
- RMANJ Reproductive Medicine Associates of New Jersey, Morristown, New Jersey, United States of America; Division of Reproductive Endocrinology, Department of Obstetrics, Gynecology, and Reproductive Science, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Dmitry A Ovchinnikov
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, Queensland, Australia
| | - Ernst J Wolvetang
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, Queensland, Australia
| | - Laurence de Torrenté
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Jessica C Mar
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America; Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, United States of America
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Gilchrist GC, Kurjanowicz P, Mereilles FV, King WA, LaMarre J. Telomere Length and Telomerase Activity in Bovine Pre-implantation EmbryosIn Vitro. Reprod Domest Anim 2014; 50:58-67. [DOI: 10.1111/rda.12449] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 10/05/2014] [Indexed: 11/27/2022]
Affiliation(s)
- GC Gilchrist
- Department of Biomedical Sciences; University of Guelph; Guelph ON Canada
| | - P Kurjanowicz
- Department of Physiology (Reproductive & Development Platform); University of Toronto; Toronto ON Canada
| | - FV Mereilles
- Department of Veterinary Medicine; Faculty of Animal Science and Food Engineering; University of São Paulo; Pirassununga SP Brazil
| | - WA King
- Department of Biomedical Sciences; University of Guelph; Guelph ON Canada
| | - J LaMarre
- Department of Biomedical Sciences; University of Guelph; Guelph ON Canada
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Mania A, Mantzouratou A, Delhanty JD, Baio G, Serhal P, Sengupta SB. Telomere length in human blastocysts. Reprod Biomed Online 2014; 28:624-37. [DOI: 10.1016/j.rbmo.2013.12.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 12/10/2013] [Accepted: 12/18/2013] [Indexed: 11/27/2022]
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Telomere length reprogramming in embryos and stem cells. BIOMED RESEARCH INTERNATIONAL 2014; 2014:925121. [PMID: 24719895 PMCID: PMC3955682 DOI: 10.1155/2014/925121] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 01/15/2014] [Indexed: 01/20/2023]
Abstract
Telomeres protect and cap linear chromosome ends, yet these genomic buffers erode over an organism's lifespan. Short telomeres have been associated with many age-related conditions in humans, and genetic mutations resulting in short telomeres in humans manifest as syndromes of precocious aging. In women, telomere length limits a fertilized egg's capacity to develop into a healthy embryo. Thus, telomere length must be reset with each subsequent generation. Although telomerase is purportedly responsible for restoring telomere DNA, recent studies have elucidated the role of alternative telomeres lengthening mechanisms in the reprogramming of early embryos and stem cells, which we review here.
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Yamada-Fukunaga T, Yamada M, Hamatani T, Chikazawa N, Ogawa S, Akutsu H, Miura T, Miyado K, Tarín JJ, Kuji N, Umezawa A, Yoshimura Y. Age-associated telomere shortening in mouse oocytes. Reprod Biol Endocrinol 2013; 11:108. [PMID: 24261933 PMCID: PMC3842639 DOI: 10.1186/1477-7827-11-108] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Accepted: 11/15/2013] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Oocytes may undergo two types of aging. The first is induced by exposure to an aged ovarian microenvironment before being ovulated, known as 'reproductive or maternal aging', and the second by either a prolonged stay in the oviduct before fertilization or in vitro aging prior to insemination, known as 'postovulatory aging'. However, the molecular mechanisms underlying these aging processes remain to be elucidated. As telomere shortening in cultured somatic cells triggers replicative senescence, telomere shortening in oocytes during reproductive and postovulatory aging may predict developmental competence. This study aimed to ascertain the mechanisms underlying altered telomere biology in mouse oocytes during reproductive and postovulatory aging. METHODS We studied Tert expression patterns, telomerase activity, cytosolic reactive oxygen species (ROS) production, and telomere length in fresh oocytes from young versus reproductively-aged female mice retrieved from oviducts at 14 h post-human chorionic gonadotropin (hCG), in vivo or in vitro postovulatory-aged mouse oocytes at 23 h post-hCG. Oocytes were collected from super-ovulated C57BL/6 J mice of 6-8 weeks or 42-48 weeks of age. mRNA and protein expressions of the Tert gene were quantified using real-time quantitative reverse transcriptase polymerase chain reaction (Q-PCR) and immunochemistry. Telomerase activity was measured by a telomeric repeat amplification protocol assay, while telomere length was measured by Q-PCR and quantitative fluorescence in situ hybridization analyses. RESULTS The abundance of Tert expression in oocytes significantly decreased during reproductive and postovulatory aging. Immunofluorescent staining clearly demonstrated an altered pattern and intensity of TERT protein expression in oocytes during reproductive aging. Furthermore, relative telomerase activity (RTA) in oocytes from reproductively-aged females was significantly lower than that in oocytes from young females. In contrast, RTA in postovulatory-aged oocytes was similar to that in fresh oocytes. Oocytes from reproductively-aged females and postovulatory-aged oocytes showed higher ROS levels than oocytes from young females. Relative telomere length (RTL) was remarkably shorter in oocytes from reproductively-aged females compared to oocytes from young females. However, postovulatory aging had no significant effect on RTL of oocytes. CONCLUSIONS Long-term adverse effects of low telomerase activity and increased ROS exposure are likely associated with telomere shortening in oocytes from reproductively-aged female mice.
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Affiliation(s)
- Tomoko Yamada-Fukunaga
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
| | - Mitsutoshi Yamada
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
| | - Toshio Hamatani
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
| | - Nana Chikazawa
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
| | - Seiji Ogawa
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
| | - Hidenori Akutsu
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Ohkura Setagaya-ku, Tokyo 157-8535, Japan
| | - Takumi Miura
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Ohkura Setagaya-ku, Tokyo 157-8535, Japan
| | - Kenji Miyado
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Ohkura Setagaya-ku, Tokyo 157-8535, Japan
| | - Juan J Tarín
- Department of Functional Biology and Physical Anthropology, Faculty of Biological Sciences, University of Valencia, Burjassot, Valencia, Spain
| | - Naoaki Kuji
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
| | - Akihiro Umezawa
- Department of Reproductive Biology, National Research Institute for Child Health and Development, 2-10-1 Ohkura Setagaya-ku, Tokyo 157-8535, Japan
| | - Yasunori Yoshimura
- Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
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Ozturk S, Sozen B, Demir N. Telomere length and telomerase activity during oocyte maturation and early embryo development in mammalian species. Mol Hum Reprod 2013; 20:15-30. [DOI: 10.1093/molehr/gat055] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Analysis of telomere length in couples experiencing idiopathic recurrent pregnancy loss. J Assist Reprod Genet 2013; 30:793-8. [PMID: 23608779 DOI: 10.1007/s10815-013-9993-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Accepted: 03/31/2013] [Indexed: 01/14/2023] Open
Abstract
PURPOSE Telomere length plays a significant role in various disorders; however, its role in idiopathic recurrent pregnancy loss (iRPL) is not known. The objective of this study was to assess telomere length in peripheral blood leukocytes in couples experiencing unexplained recurrent pregnancy loss (iRPL). METHODS The study included 25 couples experiencing iRPL and 20 controls. The mean relative telomere length was measured by quantitative Real Time PCR (Q-PCR) based assay, which measures the average ratio of telomere repeat copy number to a single copy gene (36B4) copy number (T/S ratio) in each sample. RESULTS The relative leukocyte mean telomere length (T/S) in both men and women from iRPL group was significantly lower (p < 0.05) when compared to controls. A significant (P < 0.05) negative correlation was found between age and leukocyte telomere length (T/S ratio). Among the sperm parameters seminal volume was found to be negatively (r = -0.4679) associated with the telomere T/S ratio. The DNA fragmentation index of sperm showed positive correlation (r = 0.4744) with telomere length. In this preliminary study, we found that shorter telomere length in both men and women may be associated with early pregnancy loss. CONCLUSION In conclusion, shorter telomere length in both male and female partners appears to play a role in the idiopathic recurrent pregnancy loss. Loss of telomeric DNA due to oxidative stress needs further analysis. Analysis of telomere length in germ cells are needed to further substantiate the findings of this study.
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Aviv A, Susser E. Leukocyte telomere length and the father's age enigma: implications for population health and for life course. Int J Epidemiol 2013; 42:457-62. [PMID: 23382366 PMCID: PMC3619950 DOI: 10.1093/ije/dys236] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
What are the implications for population health of the demographic trend toward increasing paternal age at conception (PAC) in modern societies? We propose that the effects of older PAC are likely to be broad and harmful in some domains of health but beneficial in others. Harmful effects of older PAC have received the most attention. Thus, for example, older PAC is associated with an increased risk of offspring having rare conditions such as achondroplasia and Marfan syndrome, as well as with neurodevelopmental disorders such as autism. However, newly emerging evidence in the telomere field suggests potentially beneficial effects, since older PAC is associated with a longer leukocyte telomere length (LTL) in offspring, and a longer LTL is associated with a reduced risk of atherosclerosis and with increased survival in the elderly. Thus, older PAC may cumulatively increase resistance to atherosclerosis and lengthen lifespan in successive generations of modern humans. In this paper we: (i) introduce these novel findings; (ii) discuss potential explanations for the effect of older PAC on offspring LTL; (iii) draw implications for population health and for life course; (iv) put forth an evolutionary perspective as a context for the multigenerational effects of PAC; and (v) call for broad and intensive research to understand the mechanisms underlying the effects of PAC. We draw together work across a range of disciplines to offer an integrated perspective of this issue.
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Affiliation(s)
- Abraham Aviv
- The Center of Human Development and Aging, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA.
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Turner S, Hartshorne GM. Telomere lengths in human pronuclei, oocytes and spermatozoa. Mol Hum Reprod 2013; 19:510-8. [PMID: 23519357 DOI: 10.1093/molehr/gat021] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Telomeres are chromosome ends that control functions related to cell division. Short telomeres are proposed to underlie infertility, female reproductive ageing and abnormal embryogenesis, but there is little direct evidence on telomere length in gametes and embryos. The aim of this study was to measure telomere lengths in individual human oocytes, spermatozoa, male and female pronuclei, in order to compare parental contributions to telomere lengths in the human zygote. Quantitative fluorescence in situ hybridization was used to measure average telomere length in pronuclei of oocytes fertilized for research using a known fertile sperm sample. Pronuclei derived from male and female gametes were distinguished by 5-methylcytosine staining. Results were compared with those for unfertilized mature and immature oocytes and individual spermatozoa decondensed in vitro. Fifty unselected men and one sperm donor provided semen samples and 32 women donated oocytes surplus to IVF treatment. Telomeres in mature oocytes and female pronuclei were significantly longer than those in individual spermatozoa and male pronuclei (P < 0.0001). Telomeres were longer in immature oocytes than in mature oocytes (P < 0.04). Sperm telomere length increased with male age (P < 0.05). Neither sperm nor oocyte telomere lengths were significantly associated with clinical parameters or outcome of treatment. In conclusion, telomere length measurements directly comparing human pronuclei under identical conditions show that male-derived telomeres are shorter on average than female-derived telomeres at fertilization. We propose that from this starting point, telomere lengths are probably modified by recombination events in the oocyte until telomerase increases at the blastocyst stage. Our findings do not support the use of gamete telomere lengths as a fertility diagnostic tool.
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Affiliation(s)
- S Turner
- Division of Reproductive Health, Warwick Medical School, University of Warwick, Coventry CV2 2DX, UK
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