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Graham EL, Fernandez J, Gandhi S, Choudhry I, Kellam N, LaRocque JR. The impact of developmental stage, tissue type, and sex on DNA double-strand break repair in Drosophila melanogaster. PLoS Genet 2024; 20:e1011250. [PMID: 38683763 PMCID: PMC11057719 DOI: 10.1371/journal.pgen.1011250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 04/04/2024] [Indexed: 05/02/2024] Open
Abstract
Accurate repair of DNA double-strand breaks (DSBs) is essential for the maintenance of genome integrity, as failure to repair DSBs can result in cell death. The cell has evolved two main mechanisms for DSB repair: non-homologous end-joining (NHEJ) and homology-directed repair (HDR), which includes single-strand annealing (SSA) and homologous recombination (HR). While certain factors like age and state of the chromatin are known to influence DSB repair pathway choice, the roles of developmental stage, tissue type, and sex have yet to be elucidated in multicellular organisms. To examine the influence of these factors, DSB repair in various embryonic developmental stages, larva, and adult tissues in Drosophila melanogaster was analyzed through molecular analysis of the DR-white assay using Tracking across Indels by DEcomposition (TIDE). The proportion of HR repair was highest in tissues that maintain the canonical (G1/S/G2/M) cell cycle and suppressed in both terminally differentiated and polyploid tissues. To determine the impact of sex on repair pathway choice, repair in different tissues in both males and females was analyzed. When molecularly examining tissues containing mostly somatic cells, males and females demonstrated similar proportions of HR and NHEJ. However, when DSB repair was analyzed in male and female premeiotic germline cells utilizing phenotypic analysis of the DR-white assay, there was a significant decrease in HR in females compared to males. This study describes the impact of development, tissue-specific cycling profile, and, in some cases, sex on DSB repair outcomes, underscoring the complexity of repair in multicellular organisms.
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Affiliation(s)
- Elizabeth L. Graham
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Joel Fernandez
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Shagun Gandhi
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Iqra Choudhry
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Natalia Kellam
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Jeannine R. LaRocque
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
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2
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Ye Y, Homer HA. A surge in cytoplasmic viscosity triggers nuclear remodeling required for Dux silencing and pre-implantation embryo development. Cell Rep 2024; 43:113917. [PMID: 38446665 DOI: 10.1016/j.celrep.2024.113917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 12/17/2023] [Accepted: 02/16/2024] [Indexed: 03/08/2024] Open
Abstract
Embryonic genome activation (EGA) marks the transition from dependence on maternal transcripts to an embryonic transcriptional program. The precise temporal regulation of gene expression, specifically the silencing of the Dux/murine endogenous retrovirus type L (MERVL) program during late 2-cell interphase, is crucial for developmental progression in mouse embryos. How this finely tuned regulation is achieved within this specific window is poorly understood. Here, using particle-tracking microrheology throughout the mouse oocyte-to-embryo transition, we identify a surge in cytoplasmic viscosity specific to late 2-cell interphase brought about by high microtubule and endomembrane density. Importantly, preventing the rise in 2-cell viscosity severely impairs nuclear reorganization, resulting in a persistently open chromatin configuration and failure to silence Dux/MERVL. This, in turn, derails embryo development beyond the 2- and 4-cell stages. Our findings reveal a mechanical role of the cytoplasm in regulating Dux/MERVL repression via nuclear remodeling during a temporally confined period in late 2-cell interphase.
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Affiliation(s)
- Yunan Ye
- The Christopher Chen Oocyte Biology Research Laboratory, Centre for Clinical Research, The University of Queensland, Herston, QLD 4029, Australia
| | - Hayden Anthony Homer
- The Christopher Chen Oocyte Biology Research Laboratory, Centre for Clinical Research, The University of Queensland, Herston, QLD 4029, Australia.
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3
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Leem J, Lee C, Choi DY, Oh JS. Distinct characteristics of the DNA damage response in mammalian oocytes. Exp Mol Med 2024; 56:319-328. [PMID: 38355825 PMCID: PMC10907590 DOI: 10.1038/s12276-024-01178-2] [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: 08/20/2023] [Revised: 11/15/2023] [Accepted: 12/07/2023] [Indexed: 02/16/2024] Open
Abstract
DNA damage is a critical threat that poses significant challenges to all cells. To address this issue, cells have evolved a sophisticated molecular and cellular process known as the DNA damage response (DDR). Among the various cell types, mammalian oocytes, which remain dormant in the ovary for extended periods, are particularly susceptible to DNA damage. The occurrence of DNA damage in oocytes can result in genetic abnormalities, potentially leading to infertility, birth defects, and even abortion. Therefore, understanding how oocytes detect and repair DNA damage is of paramount importance in maintaining oocyte quality and preserving fertility. Although the fundamental concept of the DDR is conserved across various cell types, an emerging body of evidence reveals striking distinctions in the DDR between mammalian oocytes and somatic cells. In this review, we highlight the distinctive characteristics of the DDR in oocytes and discuss the clinical implications of DNA damage in oocytes.
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Affiliation(s)
- Jiyeon Leem
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
| | - Crystal Lee
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
| | - Da Yi Choi
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
| | - Jeong Su Oh
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea.
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4
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Partscht P, Schiebel E. The diverging role of CDC14B: from mitotic exit in yeast to cell fate control in humans. EMBO J 2023; 42:e114364. [PMID: 37493185 PMCID: PMC10425841 DOI: 10.15252/embj.2023114364] [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: 04/25/2023] [Revised: 05/22/2023] [Accepted: 07/07/2023] [Indexed: 07/27/2023] Open
Abstract
CDC14, originally identified as crucial mediator of mitotic exit in budding yeast, belongs to the family of dual-specificity phosphatases (DUSPs) that are present in most eukaryotes. Contradicting data have sparked a contentious discussion whether a cell cycle role is conserved in the human paralogs CDC14A and CDC14B but possibly masked due to redundancy. Subsequent studies on CDC14A and CDC14B double knockouts in human and mouse demonstrated that CDC14 activity is dispensable for mitotic progression in higher eukaryotes and instead suggested functional specialization. In this review, we provide a comprehensive overview of our current understanding of how faithful cell division is linked to phosphorylation and dephosphorylation and compare functional similarities and divergences between the mitotic phosphatases CDC14, PP2A, and PP1 from yeast and higher eukaryotes. Furthermore, we review the latest discoveries on CDC14B, which identify this nuclear phosphatase as a key regulator of gene expression and reveal its role in neuronal development. Finally, we discuss CDC14B functions in meiosis and possible implications in other developmental processes.
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Affiliation(s)
- Patrick Partscht
- Zentrum für Molekulare BiologieUniversität Heidelberg, DKFZ‐ZMBH AllianzHeidelbergGermany
| | - Elmar Schiebel
- Zentrum für Molekulare BiologieUniversität Heidelberg, DKFZ‐ZMBH AllianzHeidelbergGermany
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5
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Cai X, Stringer JM, Zerafa N, Carroll J, Hutt KJ. Xrcc5/Ku80 is required for the repair of DNA damage in fully grown meiotically arrested mammalian oocytes. Cell Death Dis 2023; 14:397. [PMID: 37407587 DOI: 10.1038/s41419-023-05886-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 05/07/2023] [Accepted: 06/12/2023] [Indexed: 07/07/2023]
Abstract
Mammalian oocytes spend most of their life in a unique state of cell cycle arrest at meiotic prophase I, during which time they are exposed to countless DNA-damaging events. Recent studies have shown that DNA double-strand break repair occurs predominantly via the homologous recombination (HR) pathway in small non-growing meiotically arrested oocytes (primordial follicle stage). However, the DNA repair mechanisms employed by fully grown meiotically arrested oocytes (GV-stage) have not been studied in detail. Here we established a conditional knockout mouse model to explore the role of Ku80, a critical component of the nonhomologous end joining (NHEJ) pathway, in the repair of DNA damage in GV oocytes. GV oocytes lacking Ku80 failed to repair etoposide-induced DNA damage, even when only low levels of damage were sustained. This indicates Ku80 is needed to resolve DSBs and that HR cannot compensate for a compromised NHEJ pathway in fully-grown oocytes. When higher levels of DNA damage were induced, a severe delay in M-phase entry was observed in oocytes lacking XRCC5 compared to wild-type oocytes, suggesting that Ku80-dependent repair of DNA damage is important for the timely release of oocytes from prophase I and resumption of meiosis. Ku80 was also found to be critical for chromosome integrity during meiotic maturation following etoposide exposure. These data demonstrate that Ku80, and NHEJ, are vital for quality control in mammalian GV stage oocytes and reveal that DNA repair pathway choice differs in meiotically arrested oocytes according to growth status.
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Affiliation(s)
- Xuebi Cai
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Jessica M Stringer
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Nadeen Zerafa
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - John Carroll
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Karla J Hutt
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
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6
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Miao X, Guo R, Williams A, Lee C, Ma J, Wang PJ, Cui W. Replication Protein A1 is essential for DNA damage repair during mammalian oogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.04.547725. [PMID: 37461444 PMCID: PMC10349974 DOI: 10.1101/2023.07.04.547725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Persistence of unrepaired DNA damage in oocytes is detrimental and may cause genetic aberrations, miscarriage, and infertility. RPA, an ssDNA-binding complex, is essential for various DNA-related processes. Here we report that RPA plays a novel role in DNA damage repair during postnatal oocyte development after meiotic recombination. To investigate the role of RPA during oogenesis, we inactivated RPA1 (replication protein A1), the largest subunit of the heterotrimeric RPA complex, specifically in oocytes using two germline-specific Cre drivers (Ddx4-Cre and Zp3-Cre). We find that depletion of RPA1 leads to the disassembly of the RPA complex, as evidenced by the absence of RPA2 and RPA3 in RPA1-deficient oocytes. Strikingly, severe DNA damage occurs in RPA1-deficient GV-stage oocytes. Loss of RPA in oocytes triggered the canonical DNA damage response mechanisms and pathways, such as activation of ATM, ATR, DNA-PK, and p53. In addition, the RPA deficiency causes chromosome misalignment at metaphase I and metaphase II stages of oocytes, which is consistent with altered transcript levels of genes involved in cytoskeleton organization in RPA1-deficient oocytes. Absence of the RPA complex in oocytes severely impairs folliculogenesis and leads to a significant reduction in oocyte number and female infertility. Our results demonstrate that RPA plays an unexpected role in DNA damage repair during mammalian folliculogenesis.
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Affiliation(s)
- Xiaosu Miao
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Rui Guo
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
- NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, Anhui Medical University, Hefei, Anhui, China
| | - Andrea Williams
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Catherine Lee
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Jun Ma
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - P. Jeremy Wang
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Wei Cui
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
- Animal Models Core Facility, Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, MA, USA
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7
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Lee S, Kim HJ, Cho HB, Kim HR, Lee S, Park JI, Park KH. Melatonin loaded PLGA nanoparticles effectively ameliorate the in vitro maturation of deteriorated oocytes and the cryoprotective abilities during vitrification process. Biomater Sci 2023; 11:2912-2923. [PMID: 36883517 DOI: 10.1039/d2bm02054h] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Almost all cells can be exposed to stress, but oocytes, which are female germ cells, are particularly vulnerable to damage. In this study, melatonin, a well-known antioxidant, was loaded into biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and delivered to damaged oocytes in order to improve their quality and restoration. Etoposide (ETP)-induced deteriorated oocytes show poor maturity, mitochondrial aggregation, and DNA damage. Treatment of NPs not only reduced DNA damage but also improved mitochondrial stability, as evidenced by increased ATP levels and mitochondrial homogeneity. When melatonin was added to the culture medium at the same concentration as that present in NPs, DNA and mitochondrial repair was insignificant due to the half-life of melatonin, whereas DNA repair in damaged oocytes upon multiple treatments with melatonin was similar to that observed with melatonin-loaded NPs. Next, we evaluated whether the oocytes treated with NPs could have cryoprotective abilities during vitrification/thawing. Vitrified-oocytes were stored at -196 °C for 0.25 h (T1) or 0.5 h (T2). After thawing, live oocytes were subjected to in vitro maturation. The NP-treated group showed maturity similar to the control group (77.8% in T1, 72.7% in T2) and the degree of DNA damage was reduced compared to the ETP-induced group (p < 0.05).
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Affiliation(s)
- Sujin Lee
- Department of Biomedical Science, College of Life Science, CHA University, 6F, CHA Bio-Complex, 335 Pangyo-ro, Bundang-gu, Seongnam-si, 134-88, Republic of Kore.
| | - Hye Jin Kim
- Department of Biomedical Science, College of Life Science, CHA University, 6F, CHA Bio-Complex, 335 Pangyo-ro, Bundang-gu, Seongnam-si, 134-88, Republic of Kore.
| | - Hui Bang Cho
- Department of Biomedical Science, College of Life Science, CHA University, 6F, CHA Bio-Complex, 335 Pangyo-ro, Bundang-gu, Seongnam-si, 134-88, Republic of Kore.
| | - Hye-Ryoung Kim
- Department of Biomedical Science, College of Life Science, CHA University, 6F, CHA Bio-Complex, 335 Pangyo-ro, Bundang-gu, Seongnam-si, 134-88, Republic of Kore.
| | - Sujeong Lee
- Department of Biomedical Science, College of Life Science, CHA University, 6F, CHA Bio-Complex, 335 Pangyo-ro, Bundang-gu, Seongnam-si, 134-88, Republic of Kore.
| | - Ji-In Park
- Department of Biomedical Science, College of Life Science, CHA University, 6F, CHA Bio-Complex, 335 Pangyo-ro, Bundang-gu, Seongnam-si, 134-88, Republic of Kore.
| | - Keun-Hong Park
- Department of Biomedical Science, College of Life Science, CHA University, 6F, CHA Bio-Complex, 335 Pangyo-ro, Bundang-gu, Seongnam-si, 134-88, Republic of Kore.
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8
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PAK2 is essential for chromosome alignment in metaphase I oocytes. Cell Death Dis 2023; 14:150. [PMID: 36813765 PMCID: PMC9947007 DOI: 10.1038/s41419-023-05585-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 02/24/2023]
Abstract
As a highly conserved and ubiquitously expressed serine/threonine kinase, p21-activated kinase 2 (PAK2) participates in diverse biologic events. However, its roles in mouse oocyte meiotic maturation remain unclear. The present study revealed that mouse oocytes depleted of Pak2 were unable to completely progress through meiosis and that a majority were arrested at metaphase I. Pak2 depletion thus prompted MI arrest and induced meiotic chromosome alignment defects in mouse oocytes, in part due to a reduction in polo-like kinase (PLK1). We demonstrated that PAK2's interaction with PLK1 protected it from degradation by APC/CCdh1, and that it promoted meiotic progression and bipolar spindle formation. Our data collectively display critical functions for PAK2 in meiotic progression and chromosome alignment in mouse oocytes.
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9
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Lee C, Leem J, Oh JS. Selective utilization of non-homologous end-joining and homologous recombination for DNA repair during meiotic maturation in mouse oocytes. Cell Prolif 2022; 56:e13384. [PMID: 36564861 PMCID: PMC10068936 DOI: 10.1111/cpr.13384] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/29/2022] [Accepted: 12/08/2022] [Indexed: 12/25/2022] Open
Abstract
DNA double-strand breaks (DSBs) are highly toxic lesions that can cause genomic instability and can be repaired by non-homologous end-joining (NHEJ) and homologous recombination (HR) pathways. Despite extensive studies about DSB repair pathways, the roles of each pathway during meiotic maturation in oocytes are not well understood. Here we show that oocytes selectively utilize NHEJ and HR to repair DSBs during meiotic maturation. Inhibition of NHEJ impaired the meiotic maturation of oocytes with DNA damage by activating the spindle assembly checkpoint (SAC) with a concomitant increase in metaphase I (MI) arrest and DNA damage levels. In contrast, oocytes with DNA damage bypassed SAC-mediated MI arrest despite the presence of fragmented DNA when HR was inhibited. Notably, this bypass of SAC arrest by HR inhibition was associated with a loss of centromere integrity and subsequent impairment of chromosome architecture. Our results demonstrate that, while NHEJ is critical for the meiotic maturation of oocytes with DNA damage, HR is essential to maintain centromere integrity against DNA damage during meiotic maturation, revealing distinct roles of NHEJ and HR during meiotic maturation in mouse oocytes.
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Affiliation(s)
- Crystal Lee
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
| | - Jiyeon Leem
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
| | - Jeong Su Oh
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, South Korea
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10
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Ye Y, Homer HA. Two‐step nuclear centring by competing microtubule‐ and actin‐based mechanisms in 2‐cell mouse embryos. EMBO Rep 2022; 23:e55251. [DOI: 10.15252/embr.202255251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 09/01/2022] [Accepted: 09/12/2022] [Indexed: 11/07/2022] Open
Affiliation(s)
- Yunan Ye
- The Christopher Chen Oocyte Biology Research Laboratory, Centre for Clinical Research The University of Queensland Herston QLD Australia
| | - Hayden A Homer
- The Christopher Chen Oocyte Biology Research Laboratory, Centre for Clinical Research The University of Queensland Herston QLD Australia
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11
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The oocyte spindle midzone pauses Cdk1 inactivation during fertilization to enable male pronuclear formation and embryo development. Cell Rep 2022; 39:110789. [PMID: 35508138 DOI: 10.1016/j.celrep.2022.110789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 02/21/2022] [Accepted: 04/13/2022] [Indexed: 11/20/2022] Open
Abstract
Inactivation of cyclin-dependent kinase 1 (Cdk1), controlled by cyclin B1 proteolysis, orders events during mitotic exit. Here, we used a FRET biosensor to study Cdk1 activity while simultaneously monitoring anaphase II and pronuclear (PN) formation in live mouse eggs throughout fertilization. We find that Cdk1 inactivation occurs over two phases separated by a 3-h pause, the first induces anaphase II and the second induces PN formation. Although both phases require the inhibitory Cdk1 kinase Wee1B, only the first involves cyclin B1 proteolysis. Enforcing the 3-h pause is critical for providing the delay required for male PN formation and is mediated by spindle midzone-dependent sequestration of Wee1B between the first and second phases. Thus, unlike continuous Cdk1 inactivation driven by cyclin B1 proteolysis during mitotic exit, MII oocytes engineer a physiologically important pause during fertilization involving two different pathways to inactivate Cdk1, only the first of which requires proteolysis.
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12
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Ji YM, Zhang KH, Pan ZN, Ju JQ, Zhang HL, Liu JC, Wang Y, Sun SC. High-dose zearalenone exposure disturbs G2/M transition during mouse oocyte maturation. Reprod Toxicol 2022; 110:172-179. [DOI: 10.1016/j.reprotox.2022.04.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 04/14/2022] [Accepted: 04/27/2022] [Indexed: 01/09/2023]
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13
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Leem J, Oh JS. MDC1 is essential for G2/M transition and spindle assembly in mouse oocytes. Cell Mol Life Sci 2022; 79:200. [PMID: 35320416 PMCID: PMC11071937 DOI: 10.1007/s00018-022-04241-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/23/2022] [Accepted: 03/09/2022] [Indexed: 11/28/2022]
Abstract
Mammalian oocytes are particularly susceptible to accumulating DNA damage. However, unlike mitotic cells in which DNA damage induces G2 arrest by activating the ATM-Chk1/2-Cdc25 pathway, oocytes readily enter M-phase immediately following DNA damage. This implies a lack of a robust canonical G2/M DNA damage checkpoint in oocytes. Here we show that MDC1 plays a non-canonical role in controlling G2/M transition by regulating APC/C-Cdh1-mediated cyclin B1 degradation in response to DNA damage in mouse oocytes. Depletion of MDC1 impaired M-phase entry by decreasing cyclin B1 levels via the APC/C-Cdh1 pathway. Notably, the APC/C-Cdh1 regulation mediated by MDC1 was achieved by a direct interaction between MDC1 and APC/C-Cdh1. This interaction was transiently disrupted after DNA damage with a concomitant increase in Cdh1 levels, which, in turn, decreased cyclin B1 levels and delayed M-phase entry. Moreover, MDC1 depletion impaired spindle assembly by decreasing the integrity of microtubule organizing centers (MTOCs). Therefore, our results demonstrate that MDC1 is an essential molecule in regulating G2/M transition in response to DNA damage and in regulating spindle assembly in mouse oocytes. These results provide new insights into the regulation of the G2/M DNA damage checkpoint and cell cycle control in oocytes.
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Affiliation(s)
- Jiyeon Leem
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, Korea
| | - Jeong Su Oh
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, Korea.
- Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, Korea.
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14
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Guo L, Liu X, Chen H, Wang W, Gu C, Li B. Decrease in ovarian reserve through the inhibition of SIRT1-mediated oxidative phosphorylation. Aging (Albany NY) 2022; 14:2335-2347. [PMID: 35275845 PMCID: PMC8954953 DOI: 10.18632/aging.203942] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/24/2022] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To establish an oxidative stress-induced model of premature ovarian insufficiency (POI) and to explore the effect of SIRT1 and mitochondrial oxidative phosphorylation on the ovarian reserve. METHODS Mice were treated with intraperitoneal injections of 3-nitropropionic acid (3-NPA) at different doses and for different time periods to induce a model of POI. Subsequently, the efficiency of each regimen was evaluated. The expression of SIRT1 in ovarian tissue was examined. Then, SIRT1 was knocked down in human luteinized granulosa cells (GCs), and its function and related receptor and gene expression were examined. Finally, a SIRT1 antagonist and agonist were used to explore the effects of SIRT1 on ovarian function in vivo and on the change in mitochondrial oxidative phosphorylation complexes (OXPHOS). RESULTS Decreases in ovarian reserve were successfully induced through the intraperitoneal injection of 40 mg/kg 3-NPA for 3 weeks, and SIRT1 was down-regulated in the model group. The knockdown of SIRT1 impaired the estrogen synthesis capacity of human GCs and decreased the expression of related genes. 3-NPA and SIRT1 antagonist Ex-527 decreased ovarian function and inhibited OXPHOS. In contrast, the SIRT1 agonist resveratrol promoted the recovery of ovarian function in the model group and improved OXPHOS. Additionally, P53, CASPASE 3, and BAX were down-regulated and BCL2 was up-regulated in the 3-NPA and Ex-527 groups; opposite trends were observed after resveratrol treatment. CONCLUSIONS The intraperitoneal injection of 40 mg/kg 3-NPA for 3 weeks could effectively induce POI. The increase in oxidative stress inhibited SRIT1 and mitochondrial oxidative phosphorylation, inducing follicular apoptosis.
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Affiliation(s)
- Lu Guo
- Department of Gynecology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China.,Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200090, China
| | - Xiaocheng Liu
- Department of Gynecology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China.,Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200090, China
| | - Hua Chen
- Department of Gynecology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China.,Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200090, China
| | - Weigui Wang
- Department of Gynecology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China.,Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200090, China
| | - Chao Gu
- Department of Gynecology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China.,Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200090, China
| | - Bin Li
- Department of Gynecology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China.,Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200090, China
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15
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Pailas A, Niaka K, Zorzompokou C, Marangos P. The DNA Damage Response in Fully Grown Mammalian Oocytes. Cells 2022; 11:cells11050798. [PMID: 35269420 PMCID: PMC8909749 DOI: 10.3390/cells11050798] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/09/2022] [Accepted: 02/17/2022] [Indexed: 11/16/2022] Open
Abstract
DNA damage in cells can occur physiologically or may be induced by exogenous factors. Genotoxic damage may cause cancer, ageing, serious developmental diseases and anomalies. If the damage occurs in the germline, it can potentially lead to infertility or chromosomal and genetic aberrations in the developing embryo. Mammalian oocytes, the female germ cells, are produced before birth, remaining arrested at the prophase stage of meiosis over a long period of time. During this extensive state of arrest the oocyte may be exposed to different DNA-damaging insults for months, years or even decades. Therefore, it is of great importance to understand how these cells respond to DNA damage. In this review, we summarize the most recent developments in the understanding of the DNA damage response mechanisms that function in fully grown mammalian oocytes.
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Affiliation(s)
- Alexandros Pailas
- Department of Biological Applications and Technology, School of Health Sciences, Institute of Biosciences, University Research Centre, University of Ioannina, 45110 Ioannina, Greece
| | - Konstantina Niaka
- Department of Biological Applications and Technology, School of Health Sciences, Institute of Biosciences, University Research Centre, University of Ioannina, 45110 Ioannina, Greece
| | - Chrysoula Zorzompokou
- Department of Biological Applications and Technology, School of Health Sciences, Institute of Biosciences, University Research Centre, University of Ioannina, 45110 Ioannina, Greece
| | - Petros Marangos
- Department of Biological Applications and Technology, School of Health Sciences, Institute of Biosciences, University Research Centre, University of Ioannina, 45110 Ioannina, Greece
- Biomedical Research Institute, Foundation for Research and Technology, University of Ioannina Campus, 45115 Ioannina, Greece
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16
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Singh AK, Kumar SL, Beniwal R, Mohanty A, Kushwaha B, Rao HBDP. Local DNA synthesis is critical for DNA repair during oocyte maturation. J Cell Sci 2021; 134:272449. [PMID: 34415018 DOI: 10.1242/jcs.257774] [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: 11/30/2020] [Accepted: 08/16/2021] [Indexed: 01/04/2023] Open
Abstract
Mammalian oocytes can be very long-lived cells and thereby are very likely to encounter DNA damage during their lifetime. Defective DNA repair may result in oocytes that are developmentally incompetent or give rise to progeny with congenital disorders. During oocyte maturation, damaged DNA is repaired primarily by non-homologous end joining (NHEJ) or homologous recombination (HR). Although these repair pathways have been studied extensively, the associated DNA synthesis is poorly characterized. Here, using porcine oocytes, we demonstrate that the DNA synthesis machinery is present during oocyte maturation and dynamically recruited to sites of DNA damage. DNA polymerase δ is identified as being crucial for oocyte DNA synthesis. Furthermore, inhibiting synthesis causes DNA damage to accumulate and delays the progression of oocyte maturation. Importantly, inhibition of the spindle assembly checkpoint (SAC) bypassed the delay of oocyte maturation caused by DNA synthesis inhibition. Finally, we found that ∼20% of unperturbed oocytes experienced spontaneously arising damage during maturation. Cumulatively, our findings indicate that oocyte maturation requires damage-associated DNA synthesis that is monitored by the SAC. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Ajay K Singh
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500032, India
| | - S Lava Kumar
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500032, India.,Graduate studies, Regional Centre for Biotechnology, Faridabad 121 001, India
| | - Rohit Beniwal
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500032, India.,Graduate studies, Regional Centre for Biotechnology, Faridabad 121 001, India
| | - Aradhana Mohanty
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500032, India.,Graduate studies, Regional Centre for Biotechnology, Faridabad 121 001, India
| | - Bhawna Kushwaha
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500032, India
| | - H B D Prasada Rao
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500032, India
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17
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Greaney J, Subramanian GN, Ye Y, Homer H. Isolation and in vitro Culture of Mouse Oocytes. Bio Protoc 2021; 11:e4104. [PMID: 34458398 DOI: 10.21769/bioprotoc.4104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/11/2021] [Accepted: 04/12/2021] [Indexed: 11/02/2022] Open
Abstract
Females are endowed at birth with a fixed reserve of oocytes, which declines both in quantity and quality with advancing age. Understanding the molecular mechanisms regulating oocyte quality is crucial for improving the chances of pregnancy success in fertility clinics. In vitro culture systems enable researchers to analyse important molecular and genetic regulators of oocyte maturation and fertilisation. Here, we describe in detail a highly reproducible technique for the isolation and culture of fully grown mouse oocytes. We include the considerations and precautionary measures required for minimising the detrimental effects of in vitro culture conditions. This technique forms the starting point for a wide range of experimental approaches such as post-transcriptional gene silencing, immunocytochemistry, Western blotting, high-resolution 4D time-lapse imaging, and in vitro fertilization, which are instrumental in dissecting the molecular determinants of oocyte quality. Hence, this protocol serves as a useful, practical guide for any oocyte researcher beginning experiments aimed at investigating important oocyte molecular factors. Graphic abstract: A step-by-step protocol for the isolation and in vitro culture of oocytes from mice.
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Affiliation(s)
- Jessica Greaney
- The Christopher Chen Oocyte Biology Research Laboratory, University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
| | - Goutham Narayanan Subramanian
- The Christopher Chen Oocyte Biology Research Laboratory, University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
| | - Yunan Ye
- The Christopher Chen Oocyte Biology Research Laboratory, University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
| | - Hayden Homer
- The Christopher Chen Oocyte Biology Research Laboratory, University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
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18
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Ma JY, Feng X, Xie FY, Li S, Chen LN, Luo SM, Yin S, Ou XH. Double-strand breaks induce short-scale DNA replication and damage amplification in the fully grown mouse oocytes. Genetics 2021; 218:iyab054. [PMID: 33792683 PMCID: PMC8225347 DOI: 10.1093/genetics/iyab054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/26/2021] [Indexed: 12/20/2022] Open
Abstract
Break-induced replication (BIR) is essential for the repair of DNA double-strand breaks (DSBs) with single ends. DSBs-induced microhomology-mediated BIR (mmBIR) and template-switching can increase the risk of complex genome rearrangement. In addition, DSBs can also induce the multi-invasion-mediated DSB amplification. The mmBIR-induced genomic rearrangement has been identified in cancer cells and patients with rare diseases. However, when and how mmBIR is initiated have not been fully and deeply studied. Furthermore, it is not well understood about the conditions for initiation of multi-invasion-mediated DSB amplification. In the G2 phase oocyte of mouse, we identified a type of short-scale BIR (ssBIR) using the DNA replication indicator 5-ethynyl-2'-deoxyuridine (EdU). These ssBIRs could only be induced in the fully grown oocytes but not the growing oocytes. If the DSB oocytes were treated with Rad51 or Chek1/2 inhibitors, both EdU signals and DSB marker γH2A.X foci would decrease. In addition, the DNA polymerase inhibitor Aphidicolin could inhibit the ssBIR and another inhibitor ddATP could reduce the number of γH2A.X foci in the DSB oocytes. In conclusion, our results showed that DNA DSBs in the fully grown oocytes can initiate ssBIR and be amplified by Rad51 or DNA replication.
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Affiliation(s)
- Jun-Yu Ma
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Xie Feng
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou 510515, China
| | - Feng-Yun Xie
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Sen Li
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Lei-Ning Chen
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Shi-Ming Luo
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Shen Yin
- College of Life Sciences, Institute of Reproductive Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Xiang-Hong Ou
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou 510320, China
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19
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Homer HA. Senataxin: A New Guardian of the Female Germline Important for Delaying Ovarian Aging. Front Genet 2021; 12:647996. [PMID: 33995483 PMCID: PMC8118517 DOI: 10.3389/fgene.2021.647996] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 04/08/2021] [Indexed: 12/01/2022] Open
Abstract
Early decline in ovarian function known as premature ovarian aging (POA) occurs in around 10% of women and is characterized by a markedly reduced ovarian reserve. Premature ovarian insufficiency (POI) affects ~1% of women and refers to the severe end of the POA spectrum in which, accelerated ovarian aging leads to menopause before 40 years of age. Ovarian reserve refers to the total number of follicle-enclosed oocytes within both ovaries. Oocyte DNA integrity is a critical determinant of ovarian reserve since damage to DNA of oocytes within primordial-stage follicles triggers follicular apoptosis leading to accelerated follicle depletion. Despite the high prevalence of POA, very little is known regarding its genetic causation. Another little-investigated aspect of oocyte DNA damage involves low-grade damage that escapes apoptosis at the primordial follicle stage and persists throughout oocyte growth and later follicle development. Senataxin (SETX) is an RNA/DNA helicase involved in repair of oxidative stress-induced DNA damage and is well-known for its roles in preventing neurodegenerative disease. Recent findings uncover an important role for SETX in protecting oocyte DNA integrity against aging-induced increases in oxidative stress. Significantly, this newly identified SETX-mediated regulation of oocyte DNA integrity is critical for preventing POA and early-onset female infertility by preventing premature depletion of the ovarian follicular pool and reducing the burden of low-grade DNA damage both in primordial and fully-grown oocytes.
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Affiliation(s)
- Hayden A Homer
- The Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston, QLD, Australia
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20
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Homer HA. Understanding oocyte ageing: can we influence the process as clinicians? Curr Opin Obstet Gynecol 2021; 33:218-224. [PMID: 33769423 DOI: 10.1097/gco.0000000000000708] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Oocyte quality is rate-limiting for pregnancy success and declines with age. Here, I review animal-study evidence showing dramatic reversal of oocyte ageing with mitochondrial nutrients and explore clinical evidence related to their usage. RECENT FINDINGS Oocyte ageing is strongly tied to mitochondrial dysfunction and oxidative stress. Quality-defining events occur over a protracted period (2-3 months in humans) when oocyte volume increases over 100-fold. Treating mice during the growth phase with mitochondrial modifiers such as CoQ10 combats oocyte ageing. Exciting new work shows that raising oocyte NAD+ levels also dramatically rejuvenate aged oocytes. However, evidence that any of these agents can reproducibly improve quality in humans is lacking. This is largely because there has been a focus on patients with poor ovarian response during IVF and/or low ovarian follicular pool size, rather than patients with poor oocyte quality. In addition, studies have used short-term treatment during ovarian stimulation after oocyte growth is already complete. SUMMARY Mitochondrial therapeutics such as NAD+-boosting used during the oocyte's growth phase markedly improve oocyte quality in mice. Evaluating them in humans should focus on patients with poor oocyte quality and utilise per-oocyte (rather than per-cycle) endpoints after adequate treatment that captures the growth phase when quality is defined.
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Affiliation(s)
- Hayden Anthony Homer
- Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Brisbane, Herston, Queensland, Australia
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21
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Subramanian GN, Lavin M, Homer HA. Premature ovarian ageing following heterozygous loss of Senataxin. Mol Hum Reprod 2021; 27:gaaa080. [PMID: 33337500 DOI: 10.1093/molehr/gaaa080] [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: 08/09/2020] [Revised: 11/09/2020] [Indexed: 12/21/2022] Open
Abstract
Premature loss of ovarian activity before 40 years of age is known as primary ovarian insufficiency (POI) and occurs in ∼1% of women. A more subtle decline in ovarian activity, known as premature ovarian ageing (POA), occurs in ∼10% of women. Despite the high prevalence of POA, very little is known regarding its genetic causation. Senataxin (SETX) is an RNA/DNA helicase involved in repair of oxidative stress-induced DNA damage. Homozygous mutation of SETX leads to the neurodegenerative disorder, ataxia oculomotor apraxia type 2 (AOA2). There have been reports of POI in AOA2 females suggesting a link between SETX and ovarian ageing. Here, we studied female mice lacking either one (Setx+/-) or both (Setx-/-) copies of SETX over a 12- to 14-month period. We find that DNA damage is increased in oocytes from 8-month-old Setx+/- and Setx-/- females compared with Setx+/+ oocytes leading to a marked reduction in all classes of ovarian follicles at least 4 months earlier than typically occurs in female mice. Furthermore, during a 12-month long mating trial, Setx+/- and Setx-/- females produced significantly fewer pups than Setx+/+ females from 7 months of age onwards. These data show that SETX is critical for preventing POA in mice, likely by preserving DNA integrity in oocytes. Intriguingly, heterozygous Setx loss causes an equally severe impact on ovarian ageing as homozygous Setx loss. Because heterozygous SETX disruption is less likely to produce systemic effects, SETX compromise could underpin some cases of insidious POA.
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Affiliation(s)
- G N Subramanian
- The Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston, QLD, Australia
| | - M Lavin
- Cancer and Neuroscience Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston, QLD, Australia
| | - H A Homer
- The Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston, QLD, Australia
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22
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Iljas JD, Wei Z, Homer HA. Sirt1 sustains female fertility by slowing age-related decline in oocyte quality required for post-fertilization embryo development. Aging Cell 2020; 19:e13204. [PMID: 32729989 PMCID: PMC7511857 DOI: 10.1111/acel.13204] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/21/2020] [Accepted: 07/07/2020] [Indexed: 02/06/2023] Open
Abstract
The NAD+‐dependent sirtuin deacetylase, Sirt1, regulates key transcription factors strongly implicated in ageing and lifespan. Due to potential confounding effects secondary to loss of Sirt1 function from the soma in existing whole‐animal mutants, the in vivo role of Sirt1 in oocytes (oocyte‐Sirt1) for female fertility remains unknown. We deleted Sirt1 specifically in growing oocytes and study how loss of oocyte‐Sirt1 affects a comprehensive range of female reproductive parameters including ovarian follicular reservoir, oocyte maturation, oocyte mitochondrial abundance, oxidative stress, fertilization, embryo development and fertility during ageing. Surprisingly, eliminating this key sirtuin from growing oocytes has no effect in young females. During a 10‐month‐long breeding trial, however, we find that 50% of females lacking oocyte‐Sirt1 become prematurely sterile between 9 and 11 months of age when 100% of wild‐type females remain fertile. This is not due to an accelerated age‐related decline in oocyte numbers in the absence of oocyte‐Sirt1 but to reduced oocyte developmental competence or quality. Compromised oocyte quality does not impact in vivo oocyte maturation or fertilization but leads to increased oxidative stress in preimplantation embryos that inhibits cleavage divisions. Our data suggest that defects emerge in aged females lacking oocyte‐Sirt1 due to concurrent age‐related changes such as reduced NAD+ and sirtuin expression levels, which compromise compensatory mechanisms that can cover for Sirt1 loss in younger oocytes. In contrast to evidence that increasing Sirt1 activity delays ageing, our data provide some of the only in vivo evidence that loss of Sirt1 induces premature ageing.
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Affiliation(s)
- Juvita D. Iljas
- The Christopher Chen Oocyte Biology Research Laboratory Centre for Clinical Research The University of Queensland Herston Qld Australia
| | - Zhe Wei
- The Christopher Chen Oocyte Biology Research Laboratory Centre for Clinical Research The University of Queensland Herston Qld Australia
| | - Hayden A. Homer
- The Christopher Chen Oocyte Biology Research Laboratory Centre for Clinical Research The University of Queensland Herston Qld Australia
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23
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He P, Li Z, Xu F, Ru G, Huang Y, Lin E, Peng S. AMPK Activity Contributes to G2 Arrest and DNA Damage Decrease via p53/p21 Pathways in Oxidatively Damaged Mouse Zygotes. Front Cell Dev Biol 2020; 8:539485. [PMID: 33015052 PMCID: PMC7505953 DOI: 10.3389/fcell.2020.539485] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 08/19/2020] [Indexed: 02/05/2023] Open
Abstract
In zygotes, the capacity of G2/M checkpoint and DNA repair mechanisms to respond to DNA damage varies depending on different external stressors. In our previous studies, we found that mild oxidative stress induced a G2/M phase delay in mouse zygotes fertilized in vitro, due to the activation of the spindle assembly checkpoint. However, it is unclear whether the G2/M phase delay involves G2 arrest, triggered by activation of the G2/M checkpoint, and whether AMPK, a highly conserved cellular energy sensor, is involved in G2 arrest and DNA damage repair in mouse zygotes. Here, we found that mouse zygotes treated with 0.03 mM H2O2 at 7 h post-insemination (G1 phase), went into G2 arrest in the first cleavage. Furthermore, phosphorylated H2AX, a specific DNA damage and repair marker, can be detected since the early S phase. We also observed that oxidative stress induced phosphorylation and activation of AMPK. Oxidative stress-activated AMPK first localized in the cytoplasm of the mouse zygotes in the late G1 phase and then translocated to the nucleus from the early S phase. Overall, most of the activated AMPK accumulated in the nuclei of mouse zygotes arrested in the G2 phase. Inhibition of AMPK activity with Compound C and SBI-0206965 abolished oxidative stress-induced G2 arrest, increased the activity of CDK1, and decreased the induction of cell cycle regulatory proteins p53 and p21. Moreover, bypassing G2 arrest after AMPK inhibition aggravated oxidative stress-induced DNA damage at M phase, increased the apoptotic rate of blastocysts, and reduced the formation rate of 4-cell embryos and blastocysts. Our results suggest the G2/M checkpoint and DNA repair mechanisms are operative in coping with mild oxidative stress-induced DNA damage. Further, AMPK activation plays a vital role in the regulation of the oxidative stress-induced G2 arrest through the inhibition of CDK1 activity via p53/p21 pathways, thereby facilitating the repair of DNA damage and the development and survival of oxidative stress-damaged embryos. Our study provides insights into the molecular mechanisms underlying oxidative-stress induced embryonic developmental arrest, which is crucial for the development of novel strategies to ensure viable embryo generation.
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Affiliation(s)
- Pei He
- Department of Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
- Guangdong Key Laboratory of Medical Molecular Imaging, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
- Laboratory of Molecular Cardiology, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Zhiling Li
- Department of Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
- Guangdong Key Laboratory of Medical Molecular Imaging, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
- Laboratory of Molecular Cardiology, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
- *Correspondence: Zhiling Li,
| | - Feng Xu
- Department of Respiratory Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Gaizhen Ru
- Department of Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Yue Huang
- Department of Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - En Lin
- Department of Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Sanfeng Peng
- Department of Reproductive Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, China
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