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Martin JH, Aitken RJ, Bromfield EG, Nixon B. DNA damage and repair in the female germline: contributions to ART. Hum Reprod Update 2020; 25:180-201. [PMID: 30541031 DOI: 10.1093/humupd/dmy040] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/27/2018] [Accepted: 11/06/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND DNA integrity and stability are critical determinants of cell viability. This is especially true in the female germline, wherein DNA integrity underpins successful conception, embryonic development, pregnancy and the production of healthy offspring. However, DNA is not inert; rather, it is subject to assault from various environment factors resulting in chemical modification and/or strand breakage. If structural alterations result and are left unrepaired, they have the potential to cause mutations and propagate disease. In this regard, reduced genetic integrity of the female germline ranks among the leading causes of subfertility in humans. With an estimated 10% of couples in developed countries taking recourse to ART to achieve pregnancy, the need for ongoing research into the capacity of the oocyte to detect DNA damage and thereafter initiate cell cycle arrest, apoptosis or DNA repair is increasingly more pressing. OBJECTIVE AND RATIONALE This review documents our current knowledge of the quality control mechanisms utilised by the female germline to prevent and remediate DNA damage during their development from primordial follicles through to the formation of preimplantation embryos. SEARCH METHODS The PubMed database was searched using the keywords: primordial follicle, primary follicle, secondary follicle, tertiary follicle, germinal vesical, MI, MII oocyte, zygote, preimplantation embryo, DNA repair, double-strand break and DNA damage. These keywords were combined with other phrases relevant to the topic. Literature was restricted to peer-reviewed original articles in the English language (published 1979-2018) and references within these articles were also searched. OUTCOMES In this review, we explore the quality control mechanisms utilised by the female germline to prevent, detect and remediate DNA damage. We follow the trajectory of development from the primordial follicle stage through to the preimplantation embryo, highlighting findings likely to have important implications for fertility management, age-related subfertility and premature ovarian failure. In addition, we survey the latest discoveries regarding DNA repair within the metaphase II (MII) oocyte and implicate maternal stores of endogenous DNA repair proteins and mRNA transcripts as a primary means by which they defend their genomic integrity. The collective evidence reviewed herein demonstrates that the MII oocyte can engage in the activation of major DNA damage repair pathway(s), therefore encouraging a reappraisal of the long-held paradigm that oocytes are largely refractory to DNA repair upon reaching this late stage of their development. It is also demonstrated that the zygote can exploit a number of protective strategies to mitigate the risk and/or effect the repair, of DNA damage sustained to either parental germline; affirming that DNA protection is largely a maternally driven trait but that some aspects of repair may rely on a collaborative effort between the male and female germlines. WIDER IMPLICATIONS The present review highlights the vulnerability of the oocyte to DNA damage and presents a number of opportunities for research to bolster the stringency of the oocyte's endogenous defences, with implications extending to improved diagnostics and novel therapeutic applications to alleviate the burden of infertility.
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Affiliation(s)
- Jacinta H Martin
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, Kookaburra Circuit, New Lambton Heights, NSW, Australia
| | - R John Aitken
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, Kookaburra Circuit, New Lambton Heights, NSW, Australia
| | - Elizabeth G Bromfield
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, Kookaburra Circuit, New Lambton Heights, NSW, Australia
| | - Brett Nixon
- Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, Kookaburra Circuit, New Lambton Heights, NSW, Australia
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Martin JH, Bromfield EG, Aitken RJ, Lord T, Nixon B. Double Strand Break DNA Repair occurs via Non-Homologous End-Joining in Mouse MII Oocytes. Sci Rep 2018; 8:9685. [PMID: 29946146 PMCID: PMC6018751 DOI: 10.1038/s41598-018-27892-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 06/07/2018] [Indexed: 12/12/2022] Open
Abstract
The unique biology of the oocyte means that accepted paradigms for DNA repair and protection are not of direct relevance to the female gamete. Instead, preservation of the integrity of the maternal genome depends on endogenous protein stores and/or mRNA transcripts accumulated during oogenesis. The aim of this study was to determine whether mature (MII) oocytes have the capacity to detect DNA damage and subsequently mount effective repair. For this purpose, DNA double strand breaks (DSB) were elicited using the topoisomerase II inhibitor, etoposide (ETP). ETP challenge led to a rapid and significant increase in DSB (P = 0.0002) and the consequential incidence of metaphase plate abnormalities (P = 0.0031). Despite this, ETP-treated MII oocytes retained their ability to participate in in vitro fertilisation, though displayed reduced developmental competence beyond the 2-cell stage (P = 0.02). To account for these findings, we analysed the efficacy of DSB resolution, revealing a significant reduction in DSB lesions 4 h post-ETP treatment. Notably, this response was completely abrogated by pharmacological inhibition of key elements (DNA-PKcs and DNA ligase IV) of the canonical non-homologous end joining DNA repair pathway, thus providing the first evidence implicating this reparative cascade in the protection of the maternal genome.
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Affiliation(s)
- Jacinta H Martin
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia. .,Preganancy and Reproduction Program, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia.
| | - Elizabeth G Bromfield
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia.,Preganancy and Reproduction Program, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
| | - R John Aitken
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia.,Preganancy and Reproduction Program, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
| | - Tessa Lord
- School of Molecular Biosciences, Centre for Reproductive Biology, College of Veterinary Medicine, Washington State University, Pullman, WA, 99164, USA
| | - Brett Nixon
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia.,Preganancy and Reproduction Program, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
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Cui J, Xie X. Non-coding RNAs: emerging regulatory factors in the derivation and differentiation of mammalian parthenogenetic embryonic stem cells. Cell Biol Int 2017; 41:476-483. [PMID: 28220611 DOI: 10.1002/cbin.10751] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/17/2017] [Indexed: 02/06/2023]
Abstract
Parthenogenetic embryonic stem cells (PESCs) are ESCs derived from early parthenogenetic embryos. Haploid PESCs, containing haploid DNA, originate from a single sperm or occyte, while, diploid PESCs originate from two fused occytes. Most PESC lines used so far are diploid. PESCs exhibit representative pluripotent stem cell features, such as the capacity for self-renewal and the pariticular molecular signatures. Whereas, PESCs display distinctive properties, such as differential regulation of X-chromosome inactivation (XCI) and divergent monitor of genes involved in multiple biological processes. PESCs are considered promising in the regeneration medicine and developmental biology. Non-coding RNAs (ncRNAs), especially miRNAs and lncRNAs, have garnered increasing attention over the past 2 decades. They are now known to be involved in almost all cellular processes due to their full-range regulation of gene expression. Numerous studies have indicated that embryonic stem cells (ESCs) displayed distinct signatures of ncRNA genes, which play key roles in the pluripotency and self renewal of ESCs. However, the expression pattern of ncRNAs in PESCs and their roles in the derivation and differentiation of PESCs were rarely reported. In this paper, we reviewed recent research on the derivation and differentiation of PESCs and describe the emerging role of ncRNAs in these processes.
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Affiliation(s)
- Jihong Cui
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an, 710069, China.,College of Life Science, Northwest University, Xi'an, 710069, China
| | - Xin Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an, 710069, China.,College of Life Science, Northwest University, Xi'an, 710069, China.,Institute for Integrated Medical Information (IIMI), Xi'an, 710018, China
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Martin JH, Bromfield EG, Aitken RJ, Nixon B. Biochemical alterations in the oocyte in support of early embryonic development. Cell Mol Life Sci 2017; 74:469-485. [PMID: 27604868 PMCID: PMC11107538 DOI: 10.1007/s00018-016-2356-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/28/2016] [Accepted: 09/01/2016] [Indexed: 01/01/2023]
Abstract
Notwithstanding the enormous reproductive potential encapsulated within a mature mammalian oocyte, these cells present only a limited window for fertilization before defaulting to an apoptotic cascade known as post-ovulatory oocyte aging. The only cell with the capacity to rescue this potential is the fertilizing spermatozoon. Indeed, the union of these cells sets in train a remarkable series of events that endows the oocyte with the capacity to divide and differentiate into the trillions of cells that comprise a new individual. Traditional paradigms hold that, beyond the initial stimulation of fluctuating calcium (Ca2+) required for oocyte activation, the fertilizing spermatozoon plays limited additional roles in the early embryo. While this model has now been drawn into question in view of the recent discovery that spermatozoa deliver developmentally important classes of small noncoding RNAs and other epigenetic modulators to oocytes during fertilization, it is nevertheless apparent that the primary responsibility for oocyte activation rests with a modest store of maternally derived proteins and mRNA accumulated during oogenesis. It is, therefore, not surprising that widespread post-translational modifications, in particular phosphorylation, hold a central role in endowing these proteins with sufficient functional diversity to initiate embryonic development. Indeed, proteins targeted for such modifications have been linked to oocyte activation, recruitment of maternal mRNAs, DNA repair and resumption of the cell cycle. This review, therefore, seeks to explore the intimate relationship between Ca2+ release and the suite of molecular modifications that sweep through the oocyte to ensure the successful union of the parental germlines and ensure embryogenic fidelity.
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Affiliation(s)
- Jacinta H Martin
- Discipline of Biological Sciences and Priority Research Center for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia.
| | - Elizabeth G Bromfield
- Discipline of Biological Sciences and Priority Research Center for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
| | - R John Aitken
- Discipline of Biological Sciences and Priority Research Center for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
| | - Brett Nixon
- Discipline of Biological Sciences and Priority Research Center for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
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