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Uysal F, Sukur G, Cinar O. DNMT enzymes differentially alter global DNA methylation in a stage‐dependent manner during spermatogenesis. Andrologia 2022; 54:e14357. [DOI: 10.1111/and.14357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/02/2021] [Accepted: 12/15/2021] [Indexed: 11/30/2022] Open
Affiliation(s)
- Fatma Uysal
- Department of Histology and Embryology Ankara Medipol University School of Medicine Ankara Turkey
| | - Gozde Sukur
- Ankara University Biotechnology Institute Ankara Turkey
| | - Ozgur Cinar
- Department of Histology and Embryology Ankara University School of Medicine Ankara Turkey
- Center for Assisted Reproduction Ankara University School of Medicine Ankara Turkey
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Zhang JM, Wang QY, Han XY, He QL, Liu L, Zhang YT, Meng XQ, Cheng D, Zhang TL, Liu SZ. Effects of 2,3',4,4',5-pentachlorobiphenyl exposure during pregnancy on DNA methylation in the testis of offspring in the mouse. Reprod Fertil Dev 2021; 32:1048-1059. [PMID: 32758352 DOI: 10.1071/rd19412] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 05/22/2020] [Indexed: 11/23/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants, and the widespread use of PCBs has had adverse effects on human and animal health. This study experiment explored the effects of 2,3',4,4',5-pentachlorobiphenyl (PCB118) on the mammalian reproductive system. PCB118 was administered to pregnant mice from 7.5 to 12.5 days of gestation; F1 mice were obtained and the reproductive system of F1 male mice was examined. PCB118 damaged the reproductive system in male F1 mice, as evidenced by negative effects on the testicular organ coefficient (testes weight/bodyweight), a decrease in the diameter of seminiferous tubules and a significant reduction in the anogenital distance in 35-day-old F1 mice. In addition, methylation levels of genomic DNA were reduced, with reductions in the expression of the DNA methyltransferases DNMT1, DNMT3A and DNMT3B, as well as that of the epigenetic regulatory factor ubiquitin like with PHD and ring finger domains 1 (Uhrf1). Together, the results of this study provide compelling evidence that exposure of pregnant mice to PCB118 during primordial germ cell migration in the fetus affects the reproductive system of the offspring and decreases global methylation levels in the testis.
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Affiliation(s)
- Jian-Mei Zhang
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Qiu-Yue Wang
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Xiao-Ying Han
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Qi-Long He
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Li Liu
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Yong-Tao Zhang
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Xiao-Qian Meng
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Dong Cheng
- Department of Toxicology, Shandong Center for Disease Control and Prevention, Jinan 250014, China
| | - Tian-Liang Zhang
- Department of Toxicology, Shandong Center for Disease Control and Prevention, Jinan 250014, China
| | - Shu-Zhen Liu
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan 250014, China; and Corresponding author.
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3
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Jarred EG, Bildsoe H, Western PS. Out of sight, out of mind? Germ cells and the potential impacts of epigenomic drugs. F1000Res 2018; 7. [PMID: 30613387 PMCID: PMC6305226 DOI: 10.12688/f1000research.15935.1] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/12/2018] [Indexed: 12/12/2022] Open
Abstract
Epigenetic modifications, including DNA methylation and histone modifications, determine the way DNA is packaged within the nucleus and regulate cell-specific gene expression. The heritability of these modifications provides a memory of cell identity and function. Common dysregulation of epigenetic modifications in cancer has driven substantial interest in the development of epigenetic modifying drugs. Although these drugs have the potential to be highly beneficial for patients, they act systemically and may have “off-target” effects in other cells such as the patients’ sperm or eggs. This review discusses the potential for epigenomic drugs to impact on the germline epigenome and subsequent offspring and aims to foster further examination into the possible effects of these drugs on gametes. Ultimately, the information gained by further research may improve the clinical guidelines for the use of such drugs in patients of reproductive age.
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Affiliation(s)
- Ellen G Jarred
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia.,Department of Molecular and Translational Science, Monash University, Clayton, Victoria, 3168, Australia
| | - Heidi Bildsoe
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia.,Department of Molecular and Translational Science, Monash University, Clayton, Victoria, 3168, Australia
| | - Patrick S Western
- Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia.,Department of Molecular and Translational Science, Monash University, Clayton, Victoria, 3168, Australia
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4
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Heat stress responses in spermatozoa: Mechanisms and consequences for cattle fertility. Theriogenology 2018; 113:102-112. [DOI: 10.1016/j.theriogenology.2018.02.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 02/08/2018] [Accepted: 02/10/2018] [Indexed: 01/06/2023]
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5
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Ratnam S, Bozek G, Martin T, Gallagher SJ, Payne CJ, Storb U. Ssm1b expression and function in germ cells of adult mice and in early embryos. Mol Reprod Dev 2017; 84:596-613. [PMID: 28464323 DOI: 10.1002/mrd.22826] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 04/13/2017] [Indexed: 12/17/2022]
Abstract
Ssm1b (Strain-specific modifier of DNA methylation 1b) is a Krüppel-associated box (KRAB) zinc finger gene that promotes CpG methylation in the mouse transgene HRD (Heavy chain enhancer, rearrangement by deletion). We report here that Ssm1b expression and concomitant HRD methylation are also present in the male and female germ cells of adult mice. Ssm1b is expressed in both diploid (2N) and haploid (1N) oocytes, as well as in 1N spermatids and spermatozoa, but not in 2N spermatogonia. Interestingly, Ssm1b mRNA is not detected in any other adult mouse organ examined, although Ssm1-family mRNAs are highly expressed in the heart. Reflecting strain specificity, Ssm1b expression and HRD methylation are not observed in early-stage C3H/HeJ mouse embryos; however, an Ssm1b-like gene that closely resembles an Ssm1b-like gene previously found in wild-derived mice is expressed in cultured embryonic stem cells derived from C3H/HeJ embryos, suggesting that culture conditions affect its expression. Collectively, this work demonstrates that HRD methylation by Ssm1b is more temporally restricted during spermatogenesis compared to oogenesis, and is altered when embryonic stem cells are cultured from C3H/HeJ inner cell mass cells.
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Affiliation(s)
- Sarayu Ratnam
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois
| | - Grazyna Bozek
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois
| | - Terence Martin
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois
| | - Shannon J Gallagher
- Human Molecular Genetics Program, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Christopher J Payne
- Human Molecular Genetics Program, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.,Departments of Pediatrics and Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Ursula Storb
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois
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Karimian M, Colagar AH. Association of C677T transition of the human methylenetetrahydrofolate reductase (MTHFR) gene with male infertility. Reprod Fertil Dev 2017; 28:785-94. [PMID: 25412139 DOI: 10.1071/rd14186] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 09/24/2014] [Indexed: 01/10/2023] Open
Abstract
The human methylenetetrahydrofolate reductase (MTHFR) gene encodes one of the key enzymes in folate metabolism. This gene is located on chromosome 1 (1p36.3), which has 12 exons. The aim of the present study was to investigate the possible association of the two (C677T and A1298C) polymorphisms of this gene with male infertility. In a case-control study, 250 blood samples were collected from IVF centres in Sari and Babol (Iran): 118 samples were from oligospermic men and 132 were from controls. Two single nucleotide polymorphisms of the MTHFR genotype were detected using polymerase chain reaction-restriction fragment length polymorphism. There was no association found between the A1298C variant and male infertility. However, carriers of the 677T allele (CT and TT genotypes) were at a higher risk of infertility than individuals with other genotypes (odds ratio 1.84; 95% confidence interval 1.11-3.04; P=0.0174). Structural analysis of human MTHFR flavoprotein showed that C677T transition played an important role in the change in affinity of the MTHFR-Flavin adenine dinucleotide binding site. Based on our results, we suggest that C677T transition in MTHFR may increase the risk of male infertility, and detection of the C677T polymorphism biomarker may be helpful in the screening of idiopathic male infertility.
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Affiliation(s)
- Mohammad Karimian
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar 47416-95447, Iran
| | - Abasalt Hosseinzadeh Colagar
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar 47416-95447, Iran
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Hong HH, Hu Y, Yu XQ, Zhou L, Lv MQ, Sun Y, Ren WJ, Zhou DX. Associations of C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR) gene with male infertility risk: A meta-analysis. Eur J Obstet Gynecol Reprod Biol 2017; 212:101-109. [PMID: 28363185 DOI: 10.1016/j.ejogrb.2017.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 02/20/2017] [Accepted: 03/01/2017] [Indexed: 01/11/2023]
Abstract
PURPOSE Methylenetetrahydrofolate reductase is one of the key enzymes in folate metabolism. But the association between polymorphism and the risk of male infertility is still controversial. Therefore, this study used a meta-analysis on the collection of data to analyze MTHFR gene C677T polymorphism (known as c.665 C>T, rs1801133, p.Ala222Val). METHODS PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), and Wan fang. Data were searched to identify eligible studies. We sifted the data collection by Hardy-Weinberg equilibrium calculator and used odds ratios (ORs) and 95% confidence intervals (95% CIs) to conduct data through RevMan5.0 and StataSE12.0 software. RESULTS A total of 15 studies have 3853 patients with infertility and 3613 healthy controls in this meta-analysis. Our results showed that T variant of MTHFR C677T gene polymorphism was significantly associated with an increased risk of male infertility (forT vs. C: OR=1.38, 95% CI=1.18-1.63; for TT vs. CC: OR=1.86, 95% CI=1.36-2.54; for CT vs. CC: OR=1.34, 95% CI=1.03-1.74; for TT vs. CT: OR=1.52, 95% CI=1.26-1.84; for TT vs. CT+CC: OR=1.42, 95% CI=1.19-1.70; for TT+CT versus CC: OR=1.46, 95%CI=1.05-2.04). In addition, the results indicated that T allele had the positive association which was driven by East-asian populations (random: OR=1.44, 95% CI=1.2-1.74; fixed: OR=1.39, 95% CI=1.20-1.61), Middle-eastern populations (random: OR=1.30, 95% CI=1.05-1.63; fixed: OR=1.30, 95% CI=1.05-1.63) and Mixed-race (random: OR=1.96, 95% CI=1.35-2.85; fixed: OR=1.31, 95% CI=1.20-1.43). CONCLUSION This meta-analysis suggests that MTHFR C677T polymorphism is associated with male infertility.
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Affiliation(s)
- Hui-Hui Hong
- Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an 710061, China
| | - Yan Hu
- Department of Gynecology & Oncology , Shaanxi Provincial Tumor Hospital, Xi'an 710061, China
| | - Xiao-Qing Yu
- Department of Gynecology and Obstetrics, Kangfu Hospital of Shaanxi Province, Xi'an, China
| | - Liang Zhou
- Reproductive Medicine Center, North-West Maternal and child Hospital, Xi'an 710003, China
| | - Mo-Qi Lv
- Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an 710061, China
| | - Ying Sun
- Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an 710061, China
| | - Wen-Juan Ren
- Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Reproductive Medicine Center, North-West Maternal and child Hospital, Xi'an 710003, China
| | - Dang-Xia Zhou
- Department of Pathology, Medical School, Xi'an Jiaotong University, Xi'an 710061, China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an 710061, China.
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Uysal F, Akkoyunlu G, Ozturk S. DNA methyltransferases exhibit dynamic expression during spermatogenesis. Reprod Biomed Online 2016; 33:690-702. [PMID: 27687053 DOI: 10.1016/j.rbmo.2016.08.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 01/12/2023]
Abstract
DNA methylation is one of the epigenetic marks and plays critically important functions during spermatogenesis in mammals. DNA methylation is catalysed by DNA methyltransferase (DNMT) enzymes, which are responsible for the addition of a methyl group to the fifth carbon atom of the cytosine residues within cytosine-phosphate-guanine (CpG) and non-CpG dinucleotide sites. Structurally and functionally five different DNMT enzymes have been identified in mammals, including DNMT1, DNMT2, DNMT3A, DNMT3B and DNMT3L. These enzymes mainly play roles in two DNA methylation processes: maintenance and de novo. While DNMT1 is primarily responsible for maintenance methylation via transferring methyl groups to the hemi-methylated DNA strands following DNA replication, both DNMT3A and DNMT3B are capable of methylating unmodified cytosine residues, known as de novo methylation. However, DNMT3L indirectly participates in de novo methylation, and DNMT2 carries out methylation of the cytosine 38 in the anticodon loop of aspartic acid transfer RNA. To date, many studies have been performed to determine spatial and temporal expression levels and functional features of the DNMT in the male germ cells. This review article comprehensively discusses dynamic expression of the DNMT during spermatogenesis and their relationship with male infertility development in the light of existing investigations.
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Affiliation(s)
- Fatma Uysal
- Department of Histology and Embryology, Akdeniz University, School of Medicine, Campus 07070, Antalya, Turkey
| | - Gokhan Akkoyunlu
- 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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Nieto M, Demolis P, Béhanzin E, Moreau A, Hudson I, Flores B, Stemplewski H, Salmonson T, Gisselbrecht C, Bowen D, Pignatti F. The European Medicines Agency Review of Decitabine (Dacogen) for the Treatment of Adult Patients With Acute Myeloid Leukemia: Summary of the Scientific Assessment of the Committee for Medicinal Products for Human Use. Oncologist 2016; 21:692-700. [PMID: 27091416 DOI: 10.1634/theoncologist.2015-0298] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/07/2016] [Indexed: 11/17/2022] Open
Abstract
UNLABELLED : On September 20, 2012, a marketing authorization valid throughout the European Union (EU) was issued for decitabine for the treatment of adult patients aged 65 years and older with newly diagnosed de novo or secondary acute myeloid leukemia (AML) who are not candidates for standard induction chemotherapy. Decitabine is a pyrimidine analog incorporated into DNA, where it irreversibly inhibits DNA methyltransferases through covalent adduct formation with the enzyme. The use of decitabine was studied in an open-label, randomized, multicenter phase III study (DACO-016) in patients with newly diagnosed de novo or secondary AML. Decitabine (n = 242) was compared with patient's choice with physician's advice (n = 243) of low-dose cytarabine or supportive care alone. The primary endpoint of the study was overall survival. The median overall survival in the intent-to-treat (ITT) population was 7.7 months among patients treated with decitabine compared with 5.0 months for those in the control arm (hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.69-1.04; p = .1079). Mature survival data after an additional year of follow-up were consistent with these results, with a median overall survival of 7.7 months in patients treated with decitabine and 5.0 months in the control arm (HR, 0.82; 95% CI, 0.68-0.99; p = .0373). Secondary endpoints, including response rates, progression-free survival, and event-free survival, were increased in favor of decitabine when compared with control treatment. The most common adverse drug reactions reported during treatment with decitabine are pyrexia, anemia, thrombocytopenia, febrile neutropenia, neutropenia, nausea, and diarrhea. This paper summarizes the scientific review of the application leading to approval of decitabine in the EU. The detailed scientific assessment report and product information (including the summary of product characteristics) for this product are available on the EMA website (http://www.ema.europa.eu). IMPLICATIONS FOR PRACTICE Acute myeloid leukemia (AML) remains an area of significant unmet need, especially in older patients. Older patients and those with comorbidities are often considered ineligible for standard induction therapy, and outcome for these patients is poor. Decitabine has favorable effects in terms of overall survival, which were considered clinically meaningful in the context of a manageable toxicity profile and after consideration of the lack of therapeutic alternatives for these patients. Decitabine is widely used in the treatment of AML in patients aged >60 years, as per current guidelines, including the European LeukemiaNet and the U.S. National Cancer Comprehensive Network.
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Affiliation(s)
- Maria Nieto
- European Medicines Agency, London, United Kingdom
| | - Pierre Demolis
- French National Agency for Medicines and Health Products Safety, Saint-Denis Cedex, France
| | - Eliane Béhanzin
- French National Agency for Medicines and Health Products Safety, Saint-Denis Cedex, France
| | - Alexandre Moreau
- French National Agency for Medicines and Health Products Safety, Saint-Denis Cedex, France
| | - Ian Hudson
- Medicines and Healthcare Products Regulatory Agency, London, United Kingdom
| | - Beatriz Flores
- Medicines and Healthcare Products Regulatory Agency, London, United Kingdom
| | - Henry Stemplewski
- Medicines and Healthcare Products Regulatory Agency, London, United Kingdom
| | | | | | - David Bowen
- European Medicines Agency, London, United Kingdom
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Jaiswal D, Trivedi S, Agrawal NK, Singh K. Association of the patterns of global DNA methylation and expression analysis of DNA methyltransferases in impaired spermatogenic patients. ASIAN PACIFIC JOURNAL OF REPRODUCTION 2015. [DOI: 10.1016/j.apjr.2015.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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11
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Nikzad H, Karimian M, Sareban K, Khoshsokhan M, Hosseinzadeh Colagar A. MTHFR-Ala222Val and male infertility: a study in Iranian men, an updated meta-analysis and an in silico-analysis. Reprod Biomed Online 2015; 31:668-80. [DOI: 10.1016/j.rbmo.2015.07.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 07/27/2015] [Accepted: 07/30/2015] [Indexed: 12/13/2022]
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Kläver R, Sánchez V, Damm OS, Redmann K, Lahrmann E, Sandhowe-Klaverkamp R, Rohde C, Wistuba J, Ehmcke J, Schlatt S, Gromoll J. Direct but no transgenerational effects of decitabine and vorinostat on male fertility. PLoS One 2015; 10:e0117839. [PMID: 25692788 PMCID: PMC4334483 DOI: 10.1371/journal.pone.0117839] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 12/31/2014] [Indexed: 11/18/2022] Open
Abstract
Establishment and maintenance of the correct epigenetic code is essential for a plethora of physiological pathways and disturbed epigenetic patterns can provoke severe consequences, e.g. tumour formation. In recent years, epigenetic drugs altering the epigenome of tumours actively have been developed for anti-cancer therapies. However, such drugs could potentially also affect other physiological pathways and systems in which intact epigenetic patterns are essential. Amongst those, male fertility is one of the most prominent. Consequently, we addressed possible direct effects of two epigenetic drugs, decitabine and vorinostat, on both, the male germ line and fertility. In addition, we checked for putative transgenerational epigenetic effects on the germ line of subsequent generations (F1-F3). Parental adult male C57Bl/6 mice were treated with either decitabine or vorinostat and analysed as well as three subsequent untreated generations derived from these males. Treatment directly affected several reproductive parameters as testis (decitabine & vorinostat) and epididymis weight, size of accessory sex glands (vorinostat), the height of the seminiferous epithelium and sperm concentration and morphology (decitabine). Furthermore, after decitabine administration, DNA methylation of a number of loci was altered in sperm. However, when analysing fertility of treated mice (fertilisation, litter size and sex ratio), no major effect of the selected epigenetic drugs on male fertility was detected. In subsequent generations (F1-F3 generations) only subtle changes on reproductive organs, sperm parameters and DNA methylation but no overall effect on fertility was observed. Consequently, in mice, decitabine and vorinostat neither affected male fertility per se nor caused marked transgenerational effects. We therefore suggest that both drugs do not induce major adverse effects-in terms of male fertility and transgenerational epigenetic inheritance-when used in anti-cancer-therapies.
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Affiliation(s)
- Ruth Kläver
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany
| | - Victoria Sánchez
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany
| | - Oliver S Damm
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany
| | - Klaus Redmann
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany
| | - Elisabeth Lahrmann
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany
| | - Reinhild Sandhowe-Klaverkamp
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany
| | - Christian Rohde
- Department of Hematology and Oncology, University of Halle, Halle, Germany
| | - Joachim Wistuba
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany
| | - Jens Ehmcke
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany; Central Animal Facility of the Medical Faculty, University of Münster, Münster, Germany
| | - Stefan Schlatt
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany
| | - Jörg Gromoll
- Institute of Reproductive and Regenerative Biology, Centre of Reproductive Medicine and Andrology, University of Münster, Münster, Germany
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Polymorphism in DNMT1 may modify the susceptibility to oligospermia. Reprod Biomed Online 2014; 28:644-9. [DOI: 10.1016/j.rbmo.2014.01.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 01/03/2014] [Accepted: 01/07/2014] [Indexed: 12/16/2022]
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14
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Gupta N, Sarkar S, David A, Gangwar PK, Gupta R, Khanna G, Sankhwar SN, Khanna A, Rajender S. Significant impact of the MTHFR polymorphisms and haplotypes on male infertility risk. PLoS One 2013; 8:e69180. [PMID: 23874907 PMCID: PMC3715460 DOI: 10.1371/journal.pone.0069180] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 06/05/2013] [Indexed: 11/19/2022] Open
Abstract
Background Methylenetetrahydrofolate reductase (MTHFR) converts 5,10-methylene tetrahydrofolate to 5-methyl tetrahydrofolate and affects the activity of cellular cycles participating in nucleotide synthesis, DNA repair, genome stability, maintenance of methyl pool, and gene regulation. Genetically compromised MTHFR activity has been suggested to affect male fertility. The objective of the present study was to find the impact on infertility risk of c.203G>A, c.1298A>C, and c.1793G>A polymorphisms in the MTHFR gene. Methods PCR-RFLP and DNA sequencing were used to genotype the common SNPs in the MTHFR gene in 630 infertile and 250 fertile males. Chi-square test was applied for statistical comparison of genotype data. Linkage disequilibrium between the SNPs and the frequency of common haplotypes were assessed using Haploview software. Biochemical levels of total homocysteine (tHcy) and folic acid were measured. Meta-analysis on c.1298A>C polymorphism was performed using data from ten studies, comprising 2734 cases and 2737 controls. Results c.203G>A and c.1298A>C were found to be unrelated to infertility risk. c.1793G>A was protective against infertility (P = 0.0008). c.677C>T and c.1793G>A were in significant LD (D’ = 0.9). Folic acid and tHcy level did not correlate with male infertility. Pooled estimate on c.1298A>C data from all published studies including our data showed no association of this polymorphism with male infertility (Odds ratio = 1.035, P = 0.56), azoospermia (Odds ratio = 0.97, P = 0.74), or oligoasthenoteratozoospermia (Odds ratio = 0.92, p = 0.29). Eight haplotypes with more than 1% frequency were detected, of which CCGA was protective against infertility (p = 0.02), but the significance of the latter was not seen after applying Bonferroni correction. Conclusion Among MTHFR polymorphisms, c.203G>A and c.1298A>C do not affect infertility risk and c.1793G>A is protective against infertility. Haplotype analysis suggested that risk factors on the MTHFR locus do not extend too long on the DNA string.
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Affiliation(s)
- Nishi Gupta
- Division of Endocrinology, Central Drug Research Institute, Lucknow, India
| | - Saumya Sarkar
- Division of Endocrinology, Central Drug Research Institute, Lucknow, India
| | - Archana David
- Ajanta Hospitals and IVF Centre Pvt. Ltd., Lucknow, India
| | | | - Richa Gupta
- Division of Endocrinology, Central Drug Research Institute, Lucknow, India
| | - Gita Khanna
- Ajanta Hospitals and IVF Centre Pvt. Ltd., Lucknow, India
| | | | - Anil Khanna
- Ajanta Hospitals and IVF Centre Pvt. Ltd., Lucknow, India
| | - Singh Rajender
- Division of Endocrinology, Central Drug Research Institute, Lucknow, India
- * E-mail:
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Affiliation(s)
- Kiran Singh
- Department of Molecular and Human Genetics, Banaras Hindu University, Varanasi, India
| | - Deepika Jaiswal
- Department of Molecular and Human Genetics, Banaras Hindu University, Varanasi, India
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Jenkins TG, Carrell DT. The sperm epigenome and potential implications for the developing embryo. Reproduction 2012; 143:727-34. [PMID: 22495887 DOI: 10.1530/rep-11-0450] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent work in the field of male fertility has yielded significant increases in our understanding of the sperm epigenome and its potential role in embryonic development. These new findings have enabled a broad classification of a normal epigenetic state in the male gamete and have provided insight into the possible etiologies of some idiopathic male infertility cases. Histone retention and modification, protamine incorporation into the chromatin, DNA methylation, and spermatozoal RNA transcripts appear to play important roles in the epigenetic state of mature sperm. These epigenetic factors may reveal a historical record of spermatogenesis, portend future functions in embryogenesis, and help to elucidate mechanism of pluripotency. In contrast to the once held dogma regarding the importance of the paternal epigenome, the unique epigenetic landscape in sperm appears to serve more than the gamete itself and is likely influential in the developing embryo. In fact, growing evidence suggests that mature sperm provide appropriate epigenetic marks that drive specific genes toward activation and contribute to the pluripotent state of the embryonic cells. Although not definitive, the current literature provides evidence for the role of the sperm epigenome in the embryo. Future work must be focused on the characterization of epigenetic abnormalities commonly found in individuals with compromised fertility to further establish this role. Additionally, studies should target the effects of environment and aging on the sperm epigenetic program and subsequent fertility loss to determine the etiology of aberrant epigenetic profiles.
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Affiliation(s)
- Timothy G Jenkins
- Andrology and IVF Laboratories, Department of Surgery, University of Utah School of Medicine, 675 Arapeen Drive, Suite 205, Salt Lake City,Utah 801-581-3740, USA
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Huang JX, Scott MB, Pu XY, Zhou-Cun A. Association between single-nucleotide polymorphisms of DNMT3L and infertility with azoospermia in Chinese men. Reprod Biomed Online 2011; 24:66-71. [PMID: 22116073 DOI: 10.1016/j.rbmo.2011.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 08/30/2011] [Accepted: 09/07/2011] [Indexed: 11/17/2022]
Abstract
The gene for DNA methyltransferase 3-like protein (DNMT3L) is essential for normal spermatogenesis and may be involved with spermatogenetic impairment and male infertility. To explore the possible association between the DNMT3L gene and male infertility, this study investigated allele, genotype and haplotype frequencies of three single nucleotide polymorphism (SNP) loci, rs2070565, rs2276248 and rs7354779, of DNMT3L in 233 infertile patients with azoospermia and 249 fertile controls from a population of Chinese men using polymerase chain reaction/restriction fragment length polymorphism. Results showed that the frequencies of allele A (20.6% versus 14.9%; P = 0.022) and the allele A carrier (GA + AA; 37.8% versus 28.1%; P = 0.027) in azoospermic patients were significantly higher than those in controls at the rs2070565 locus. The haplotype AAA frequency was significantly higher (18.1% versus 12.4%; P = 0.02) while the haplotype GAA frequency was significantly lower (53.2% versus 62.1%; P = 0.007) in infertile patients compared with fertile controls. These results indicated that SNP rs2070565, as well as haplotypes AAA and GAA, may be associated with male infertility and suggest that DNMT3L may contribute to azoospermia susceptibility in humans.
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Affiliation(s)
- Jian-Xi Huang
- Department of Biology, Dali College, Dali, Yunnan 671003, China
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Gupta N, Gupta S, Dama M, David A, Khanna G, Khanna A, Rajender S. Strong association of 677 C>T substitution in the MTHFR gene with male infertility--a study on an indian population and a meta-analysis. PLoS One 2011; 6:e22277. [PMID: 21799811 PMCID: PMC3140509 DOI: 10.1371/journal.pone.0022277] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Accepted: 06/17/2011] [Indexed: 02/02/2023] Open
Abstract
Background Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme of folate and methionine metabolism, making it crucial for DNA synthesis and methylation. The objective of this study was to analyze MTHFR gene 677C>T polymorphism in infertile male individuals from North India, followed by a meta-analysis on our data and published studies. Methodology/Principal Findings We undertook genotyping on a total of 837 individuals including well characterized infertile (N = 522) and confirmed fertile (N = 315) individuals. The SNP was typed by direct DNA sequencing. Chi square test was done for statistical analysis. Published studies were searched using appropriate keywords. Source of data collection for meta-analysis included ‘Pubmed’, ‘Ovid’ and ‘Google Scholar’. Those studies analyzing 677C>T polymorphism in male infertility and presenting all relevant data were included in meta-analysis. The genotype data for infertile subjects and fertile controls was extracted from each study. Chi square test was done to obtain odds ratio (OR) and p-value. Meta-analysis was performed using Comprehensive Meta-analysis software (Version 2). The frequency of mutant (T) allele (p = 0.0025) and genotypes (CT+TT) (p = 0.0187) was significantly higher in infertile individuals in comparison to fertile controls in our case-control study. The overall summary estimate (OR) for allele and genotype meta-analysis were 1.304 (p = 0.000), 1.310 (p = 0.000), respectively, establishing significant association of 677C>T polymorphism with male infertility. Conclusions/Significance 677C>T substitution associated strongly with male infertility in Indian population. Allele and genotype meta-analysis also supported its strong correlation with male infertility, thus establishing it as a risk factor.
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Affiliation(s)
- Nishi Gupta
- Division of Endocrinology, Central Drug Research Institute (Council of Scientific and Industrial Research), Lucknow, Uttar Pradesh, India
| | - Saraswati Gupta
- IVF Department, Ajanta Hospitals and IVF Centre Pvt. Ltd., Lucknow, Uttar Pradesh, India
| | - Madhukar Dama
- Division of Endocrinology, Central Drug Research Institute (Council of Scientific and Industrial Research), Lucknow, Uttar Pradesh, India
| | - Archana David
- IVF Department, Ajanta Hospitals and IVF Centre Pvt. Ltd., Lucknow, Uttar Pradesh, India
| | - Geeta Khanna
- IVF Department, Ajanta Hospitals and IVF Centre Pvt. Ltd., Lucknow, Uttar Pradesh, India
| | - Anil Khanna
- IVF Department, Ajanta Hospitals and IVF Centre Pvt. Ltd., Lucknow, Uttar Pradesh, India
| | - Singh Rajender
- Division of Endocrinology, Central Drug Research Institute (Council of Scientific and Industrial Research), Lucknow, Uttar Pradesh, India
- * E-mail:
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Vani GT, Mukesh N, Rama Devi P, Usha Rani P, Reddy PP. Methylenetetrahydrofolate reductase C677T polymorphism is not associated with male infertility in a South Indian population. Andrologia 2011; 44 Suppl 1:252-9. [PMID: 21729137 DOI: 10.1111/j.1439-0272.2011.01172.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Previous studies have revealed that genetic factors may be involved in regulating the mechanism of infertility, e.g., MTHFR gene polymorphism in the development of male infertility. The aim of this study is to examine whether an association exists between MTHFR C677T polymorphism and male infertility. The study was carried out by means of a PCR-RFLP assay in 206 infertile men and 230 ethnically matched controls. The statistical analysis using two-sided Fisher's exact test and Pearson chi-squared test showed CT genotype is associated nonsignificantly with male infertility (OR = 1.19, 95% CI = 0.71-1.97). Because of the lack of TT homozygotes in the controls, a combined odds ratio of CT and TT homozygotes against the control has been calculated (OR = 1.36, 95% CI = 0.83-2.22), and the same was insignificant. The overall results of the study indicate that MTHFR C677T polymorphism is not associated with male infertility.
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Affiliation(s)
- G T Vani
- Institute of Genetics and Hospital for Genetic Diseases, Osmania University, Hyderabad, India.
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20
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Wei B, Xu Z, Ruan J, Zhu M, Jin K, Zhou D, Xu Z, Hu Q, Wang Q, Wang Z. MTHFR 677C>T and 1298A>C polymorphisms and male infertility risk: a meta-analysis. Mol Biol Rep 2011; 39:1997-2002. [DOI: 10.1007/s11033-011-0946-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 05/26/2011] [Indexed: 02/02/2023]
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Minor A, Chow V, Ma S. Aberrant DNA methylation at imprinted genes in testicular sperm retrieved from men with obstructive azoospermia and undergoing vasectomy reversal. Reproduction 2011; 141:749-57. [DOI: 10.1530/rep-11-0008] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Male factor infertility has been associated with abnormal DNA methylation at imprinted genes. Little information is available on the status of imprinting in the sperm of men with azoospermia, including the association between aberrant imprinting and obstructive azoospermia (OA) or non-OA (NOA). Analysis of DNA methylation at imprinted genes in the sperm of men undergoing vasectomy reversal would aid determination of whether aberrant imprinting is associated with obstruction. Testicular sperm was retrieved from testicular biopsies obtained from men with azoospermia (N=18), including OA (N=10), NOA (N=5), and unknown pathology (N=3), and from men undergoing vasectomy reversal (N=17). Sperm was also obtained from proven fertile men (N=9). DNA methylation was investigated at multiple CpG sites within the differentially methylated regions (DMRs) of three imprinted genes,H19,IG-GTL2andMEST, using bisulphite sequencing. Unique clones representative of single cells were analyzed. We found a significant decrease in DNA methylation at theH19DMR in testicular sperm of azoospermic men compared with proven fertile men. The decrease was also significant between OA and proven fertile men, and between men undergoing vasectomy reversal and proven fertile men, suggesting that aberrant DNA methylation may be associated with obstruction. Changes in DNA methylation atIG-GTL2andMESTDMRs among groups were not significant. Our data suggest that imprinting abnormalities may be associated with obstruction and may occur in response to changes in testicular environment and not only spermatogenesis failure, as previously reported. Methylation at theH19DMR was particularly prone to modification in testicular sperm.
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22
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Zhou FC, Chen Y, Love A. Cellular DNA methylation program during neurulation and its alteration by alcohol exposure. ACTA ACUST UNITED AC 2011; 91:703-15. [PMID: 21630420 DOI: 10.1002/bdra.20820] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 02/25/2011] [Accepted: 03/04/2011] [Indexed: 02/02/2023]
Abstract
BACKGROUND Epigenetic changes are believed to be among the earliest key regulators for cell fate and embryonic development. To support this premise, it is important to understand whether or not systemic epigenetic changes coordinate with the progression of development. We have demonstrated that DNA methylation is programmed when neural stem cells differentiate (Zhou et al.,2011). Here, we analyzed the DNA methylation events that occur during early neural tube development. METHODS AND RESULTS Using immunocytochemistry, we demonstrated that the DNA methylation marks - 5-methylcytosine (5-MeC), DNA methylation binding domain 1 (MBD1), and DNA methytransferases 1 (DNMT1) were highly coordinated in temporal and spatial patterns that paralleled the progress of embryonic development. The above ontogenic program of DNA methylation was, however, subjected to environmental modification. Alcohol exposure during fetal development, which is known to cause fetal alcohol spectrum disorder, altered the density and distribution of the DNA methylation marks. The alcohol exposure (88 mM) over 6 or 44 hours at gestation day 8 (GD-8) to GD-10 altered timely DNA methylation and retarded embryonic growth. We further demonstrated that the direct inhibiting of DNA methylation with 5-aza-cytidine (5-AZA) resulted in similar growth retardation. CONCLUSIONS We identified a temporal and spatial cellular DNA methylation program after initial erasure, which parallels embryonic maturation. Alcohol delayed the cellular DNA methylation program and also retarded embryonic growth. Since direct inhibiting of DNA methylation resulted in similar retardation, alcohol thus can affect embryonic development through a epigenetic pathway.
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Affiliation(s)
- Feng C Zhou
- Department of Anatomy & Cell Biology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Gava MM, de Oliveira Chagas E, Bianco B, Christofolini DM, Pompeo ACL, Glina S, Barbosa CP. Methylenetetrahydrofolate Reductase Polymorphisms Are Related to Male Infertility in Brazilian Men. Genet Test Mol Biomarkers 2011; 15:153-7. [DOI: 10.1089/gtmb.2010.0128] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Marcello Machado Gava
- Division of Pathological Gynecology and Human Reproduction, Department of Gynecology and Obstetrics, ABC School of Medicine, Santo André, São Paulo, Brazil
- Division of Urology, Department of Surgery, ABC School of Medicine, Santo André, São Paulo, Brazil
| | - Elisangela de Oliveira Chagas
- Division of Pathological Gynecology and Human Reproduction, Department of Gynecology and Obstetrics, ABC School of Medicine, Santo André, São Paulo, Brazil
| | - Bianca Bianco
- Division of Pathological Gynecology and Human Reproduction, Department of Gynecology and Obstetrics, ABC School of Medicine, Santo André, São Paulo, Brazil
| | - Denise Maria Christofolini
- Division of Pathological Gynecology and Human Reproduction, Department of Gynecology and Obstetrics, ABC School of Medicine, Santo André, São Paulo, Brazil
| | | | - Sidney Glina
- Division of Urology, Department of Surgery, ABC School of Medicine, Santo André, São Paulo, Brazil
| | - Caio Parente Barbosa
- Division of Pathological Gynecology and Human Reproduction, Department of Gynecology and Obstetrics, ABC School of Medicine, Santo André, São Paulo, Brazil
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El Hajj N, Zechner U, Schneider E, Tresch A, Gromoll J, Hahn T, Schorsch M, Haaf T. Methylation Status of Imprinted Genes and Repetitive Elements in Sperm DNA from Infertile Males. Sex Dev 2011; 5:60-9. [DOI: 10.1159/000323806] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2010] [Indexed: 01/19/2023] Open
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Jenkins TG, Carrell DT. The paternal epigenome and embryogenesis: poising mechanisms for development. Asian J Androl 2010; 13:76-80. [PMID: 20972451 DOI: 10.1038/aja.2010.61] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The scope of paternal contributions during early embryonic development has long been considered limited. Dramatic changes in chromatin structure throughout spermatogenesis have been thought to leave the sperm void of complex layers of epigenetic regulation over the DNA blueprint, thus leaving the balance of that regulation to the oocyte. However, recent work in the fields of epigenetics and male factor infertility has placed this long-held, and now controversial dogma, in a new light. Elegant studies investigating chromatin and epigenetic modifications in the developing sperm cell have provided new insights that may establish a more critical role for the paternal epigenome in the developing embryo. DNA methylation, histone tail modifications, targeted histone retention and protamine incorporation into the chromatin have great influence in the developing sperm cell. Perturbations in the establishment and/or maintenance of any of these epigenetic marks have been demonstrated to affect fertility status, ranging in severity from mild to catastrophic. Sperm require this myriad of chromatin structural changes not only to serve a protective role to DNA throughout spermatogenesis and future delivery to the egg, but also, it appears, to contribute to the developmental program of the future embryo. This review will focus on our current understanding of the epigenetics of sperm. We will discuss sperm-specific chromatin modifications that result in genes essential to development being poised for activation early in embryonic development, the disruption of which may result in reduced fecundity.
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Affiliation(s)
- Timothy G Jenkins
- Andrology and IVF Laboratories, Department of Surgery, University of Utah, Salt Lake City, UT 84108, USA.
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Carrell DT, Hammoud SS. The human sperm epigenome and its potential role in embryonic development. Mol Hum Reprod 2009; 16:37-47. [PMID: 19906823 DOI: 10.1093/molehr/gap090] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Along with many of the genome-wide transitions in chromatin composition throughout spermatogenesis, epigenetic modifications on histone tails and DNA are continuously modified to ensure stage specific gene expression in the maturing spermatid. Recent findings have suggested that the repertoire of epigenetic modifications in the mature sperm may have a potential role in the developing embryo and alterations in the epigenetic profile have been associated with infertility. These changes include DNA demethylation and the retention of modified histones at important developmental, signaling and micro-RNA genes, which resemble the epigenetic state of an embryonic stem cell. This review assesses the significance of epigenetic changes during spermatogenesis, and provides insight on recent associations made between altered epigenetic profiles in the mature sperm and its relationship to infertility.
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Affiliation(s)
- Douglas T Carrell
- IVF and Andrology Laboratories, Departments of Surgery (Urology), Obstetrics and Gynecology, and Physiology, 675 S. Arapeen Dr, Suite #205, University of Utah School of Medicine, Salt Lake City, UT 84108, USA.
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Takashima S, Takehashi M, Lee J, Chuma S, Okano M, Hata K, Suetake I, Nakatsuji N, Miyoshi H, Tajima S, Tanaka Y, Toyokuni S, Sasaki H, Kanatsu-Shinohara M, Shinohara T. Abnormal DNA methyltransferase expression in mouse germline stem cells results in spermatogenic defects. Biol Reprod 2009; 81:155-64. [PMID: 19228594 DOI: 10.1095/biolreprod.108.074708] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Although spermatogonial stem cells (SSCs) are committed to spermatogenesis, they may also convert to an embryonic stem cell-like pluripotent state at a low frequency. Because changes in DNA methylation patterns are associated with this conversion, we examined the effect of manipulating DNA methyltransferase (Dnmt) expression on the fate of cultured SSCs, germline stem (GS) cells. Dnmt1 knockdown induced apoptosis in GS cells, which was attenuated by the loss of Trp53. In contrast, GS cells proliferated normally in vitro after Dnmt3a/Dnmt3b ablation or during Dnmt3l overexpression. However, Dnmt3a/Dnmt3b double-mutant cells showed hypomethylation in the SineB1 repetitive sequence, and Dnmt3l-overexpressing cells showed hypermethylation in major and minor satellite sequences; neither cell type formed teratomas and completed spermatogenesis following transplantation into the seminiferous tubules. Although genetic manipulation did not increase the conversion of GS cells to a pluripotent state, these results underscore the important role of DNMTs in survival and spermatogenic differentiation in SSCs.
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Affiliation(s)
- Seiji Takashima
- Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Forges T, Pellanda H, Diligent C, Monnier P, Guéant JL. Les folates : quel impact sur la fertilité ? ACTA ACUST UNITED AC 2008; 36:930-9. [DOI: 10.1016/j.gyobfe.2008.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 07/06/2008] [Indexed: 12/16/2022]
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Galetzka D, Weis E, Tralau T, Seidmann L, Haaf T. Sex-specific windows for high mRNA expression of DNA methyltransferases 1 and 3A and methyl-CpG-binding domain proteins 2 and 4 in human fetal gonads. Mol Reprod Dev 2007; 74:233-41. [PMID: 16998846 DOI: 10.1002/mrd.20615] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
DNA methyltransferases (DNMTs) and 5-methyl-CpG-binding domain proteins (MBDs) are involved in the acquisition of parent-specific epigenetic modifications in human male and female germ cells. Reverse Northern blot analyses demonstrated sex-specific differences in mRNA expression for the maintenance DNMT1 and the de novo DNMT3A in developing testis and ovary. In fetal testis DNMT1 and DNMT3A expression peaked in mitotically arrested spermatogonia around 21 weeks gestation. In fetal ovary transcriptional upregulation of DNMT1 and DNMT3A occurred during a very brief period at 16 weeks gestation, when the oocytes proceeded through meiotic prophase. Fetal gonads showed several fold higher DNMT3A expression levels than fetal brain and adult tissues. The most abundant DNMT3A isoform in fetal testis and ovary was DNMT3A2, whereas in all other analyzed tissues DNMT3A1 predominated. The catalytically inactive DNMT3A3 isoform was also present at relatively high levels in developing gonads and may perform a regulatory function(s). In both male and female fetal gonads expression of genes for MBD2 and MBD4, which may be implicated in chromatin remodeling of methylated genomic DNA sequences, was tightly linked to DNMT expression. We propose that the sex-specific time windows for concomitant upregulation of DNMT1, DNMT3A, MBD2, and MBD4 are associated with prenatal remethylation of the human male and female germ line.
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Affiliation(s)
- Danuta Galetzka
- Institute for Human Genetics, Johannes Gutenberg University, Mainz, Germany
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Forges T, Monnier-Barbarino P, Alberto JM, Guéant-Rodriguez RM, Daval JL, Guéant JL. Impact of folate and homocysteine metabolism on human reproductive health. Hum Reprod Update 2007; 13:225-38. [PMID: 17307774 DOI: 10.1093/humupd/dml063] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Folates belong to the vitamin B group and are involved in a large number of biochemical processes, particularly in the metabolism of homocysteine. Dietary or genetically determined folate deficiency leads to mild hyperhomocysteinemia, which has been associated with various pathologies. Molecular mechanisms of homocysteine-induced cellular dysfunction include increased inflammatory cytokine expression, altered nitric oxide bioavailability, induction of oxidative stress, activation of apoptosis and defective methylation. Whereas the involvement of folate metabolism and homocysteine in ageing-related diseases, in several developmental abnormalities and in pregnancy complications has given rise to a large amount of scientific work, the role of these biochemical factors in the earlier stages of mammalian reproduction and the possible preventive effects of folate supplementation on fertility have, until recently, been much less investigated. In the present article, the possible roles of folates and homocysteine in male and female subfertility and related diseases are systematically reviewed, with regard to the epidemiological, pathological, pharmacological and experimental data of the literature from the last 25 years.
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Affiliation(s)
- Thierry Forges
- Inserm U724, Laboratory of Cellular and Molecular Pathology in Nutrition, University of Nancy, Vandoeuvre les Nancy, France.
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A ZC, Yang Y, Zhang SZ, Li N, Zhang W. Single nucleotide polymorphism C677T in the methylenetetrahydrofolate reductase gene might be a genetic risk factor for infertility for Chinese men with azoospermia or severe oligozoospermia. Asian J Androl 2006; 9:57-62. [PMID: 16888682 DOI: 10.1111/j.1745-7262.2007.00225.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
AIM To analyze the distribution of the single nucleotide polymorphism (SNP) C677T in the methylenetetrahydrofolate reductase (MTHFR) gene in 355 infertile Chinese patients with idiopathic azoospermia or severe oligozoospermia and 252 fertile Chinese men as controls to explore the possible association of the SNP and male infertility. METHODS Using the polymerase chain reaction (PCR)-restriction fragment length polymorphism technique, the allele and genotype distribution of SNP C677T in the MTHFR gene were investigated in both patients and controls. RESULTS The frequencies of allele T (40.9% vs 30.4%, P = 0.002, odds ration [OR] = 1.58, 95% confidence interval [CI]: 1.24-2.02) and mutant homozygote (TT) (18.3% vs. 11.5%, P=0.023, OR=1.72, 95% CI: 1.07-2.76) as well as carrier with allele (TT + CT) (63.4% vs. 49.2%, P = 0.0005, OR = 1.79, 95% CI: 1.29-2.48) in infertile patients were significantly higher than those in controls. After patient stratification, the significant differences in distribution of the SNP between each patient subgroup and control group still remained. CONCLUSION Our findings indicate that there is an association of SNP C677T in the MTHFR gene with male infertility, suggesting that this polymorphism might be a genetic risk factor for male infertility in Chinese men.
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Affiliation(s)
- Zhou-Cun A
- Department of Medical Genetics, West China Hospital, Sichuan University, Chengdu 610041, China
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Lee HC, Jeong YM, Lee SH, Cha KY, Song SH, Kim NK, Lee KW, Lee S. Association study of four polymorphisms in three folate-related enzyme genes with non-obstructive male infertility. Hum Reprod 2006; 21:3162-70. [PMID: 16861746 DOI: 10.1093/humrep/del280] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Three typical folate metabolism enzymes-i.e. methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MS) and MS reductase (MTRR) in the folate cycle-play a critical role in DNA synthesis and methylation reactions. We evaluated whether polymorphisms of these three enzymes are associated with non-obstructive male infertility. METHOD Three hundred and sixty patients with non-obstructive infertility and 325 fertile men without any chromosomal abnormalities were included in this study. The single-nucleotide polymorphism (SNP) analysis was performed by pyrosequencing and PCR-restriction fragment length polymorphism (RFLP) analysis RESULTS The frequencies of MTHFR 677TT and MTRR 66GG genotypes were higher in non-obstructive infertile men compared with those in fertile men. By classifying 360 infertile patients into 174 azoospermia and 186 oligoasthenoteratozoospermia (OAT) subjects, the MTHFR 677TT and MS 2756GG types were significantly associated with the azoospermia group (P = 0.0227 and 0.0063, respectively). The frequency of MTRR 66GG was significant in the OAT group (P = 0.0014 versus fertile males). CONCLUSIONS By analysis of a large number of subjects and a more specific patient selection, we showed the first genetic evidence that MTHFR C677T, MS A2756G and MTRR A66G genotypes were independently associated with male infertility. Each SNP of the three enzymes may have a different impact on the folate cycle during spermatogenesis.
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Affiliation(s)
- Han-Chul Lee
- Functional Genomics Lab, CHA Research Institute, Bundang Campus, College of Medicine, Pochon CHA University, Kyunggi-Do, Republic of Korea
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Di Giaimo R, Russo GMR, Bevilacqua MA, Iovine B, Del Gaudio R, Geraci G, Russo T. The expression of de novo DNA methylase DNMT3b, of the methyl-CpG binding protein MBD2b and of 5-MCDG glycosylase shows two waves of induction during CaCO-2 cell differentiation. Gene 2005; 351:73-81. [PMID: 15823509 DOI: 10.1016/j.gene.2005.02.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Revised: 01/24/2005] [Accepted: 02/22/2005] [Indexed: 01/17/2023]
Abstract
DNA methylation plays a central role in the control of gene expression during development and cell differentiation, thus DNA methylation and demethylation processes are expected to be strictly regulated during these events. We have explored the expression levels of the genes encoding DNA methylases, methyl-CpG binding proteins and demethylases during in vitro differentiation of human carcinoma colon cells (CaCO-2) used as a model system. The results show that the global DNA methylation pattern remains constant during CaCO-2 cells differentiation indicating that required genome methylation pattern in cell differentiation was already established in the seeded cells. On the contrary, the timing of expression of several of the explored genes is tightly regulated, suggesting they are involved in the regulation of the differentiation program. In particular, the timing of expression of DNMT3b and of MBD2b and 5-MCDG shows two peaks not observed in the time courses of the expression of other genes belonging to the same families. These events, not dependent on the cell cycle synchronization, have apparently no significant impact on the overall methylation status of the genome.
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Affiliation(s)
- Rossella Di Giaimo
- Dipartimento di Genetica, Biologia Generale e Molecolare, Università di Napoli Federico II, Italy.
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Singh K, Singh SK, Sah R, Singh I, Raman R. Mutation C677T in the methylenetetrahydrofolate reductase gene is associated with male infertility in an Indian population1. ACTA ACUST UNITED AC 2005; 28:115-9. [PMID: 15811073 DOI: 10.1111/j.1365-2605.2004.00513.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A mutation (C677T) in the gene, MTHFR, is known to increase susceptibility to various multifactorial disorders. In order to assess this single nucleotide polymorphism (SNP) as risk factor for idiopathic male infertility, a case-control study was done on an Indian population. DNA from 151 cases of non-obstruction, idiopathic oligo-/azoospermia and 200 fertile males (controls) was polymerase chain reaction amplified using site-specific primers, and analysed for the mutation following HinfI-digestion. Our results show a significantly increased frequency of CT heterozygotes among infertile patients (p value <0.04). More importantly, while there were no T homozygotes in the control population, six of 151 infertile cases were T homozygous. Considering that T allele occurs in very low frequency in the control population, 677T is clearly a risk factor for infertility in the Indian population. We contend that the same could also be true for African and Southeast Asian populations where the frequency of 677T is very low. The lack of similar association in western populations could be because of the overall dietary enrichment of folates, which could nullify or minimize the effect of this polymorphism.
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Affiliation(s)
- Kiran Singh
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005, India
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Abstract
Epigenetics is a term that has changed its meaning with the increasing biological knowledge on developmental processes. However, its current application to stem cell biology is often imprecise and is conceptually problematic. This article addresses two different subjects, the definition of epigenetics and chromatin states of stem and differentiated cells. We describe mechanisms that regulate chromatin changes and provide an overview of chromatin states of stem and differentiated cells. Moreover, a modification of the current epigenetics definition is proposed that is not restricted by the heritability of gene expression throughout cell divisions and excludes translational gene expression control.
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Affiliation(s)
- Tim C Roloff
- Max Planck Institute for Molecular Genetics, Ihnestrasse 73, D-14195 Berlin, Germany
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Plachot C, Lelièvre SA. DNA methylation control of tissue polarity and cellular differentiation in the mammary epithelium. Exp Cell Res 2004; 298:122-32. [PMID: 15242767 DOI: 10.1016/j.yexcr.2004.04.024] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2004] [Revised: 04/14/2004] [Indexed: 10/26/2022]
Abstract
Alterations in gene expression accompany cell-type-specific differentiation. In complex systems where functional differentiation depends on the organization of specific cell types into highly specialized structures (tissue morphogenesis), it is not known how epigenetic mechanisms that control gene expression influence this stepwise differentiation process. We have investigated the effect of DNA methylation, a major epigenetic pathway of gene silencing, on the regulation of mammary acinar differentiation. Our in vitro model of differentiation encompasses human mammary epithelial cells that form polarized and hollow tissue structures (acini) when cultured in the presence of basement membrane components. We found that acinar morphogenesis was accompanied with chromatin remodeling, as shown by alterations in histone 4 acetylation, heterochromatin 1 protein, and histone 3 methylated on lysine 9, and with an increase in expression of MeCP2, a mediator of DNA-methylation-induced gene silencing. DNA hypomethylation induced by treatment with 5-aza-2' deoxycytidine during acinar differentiation essentially prevented the formation of apical tissue polarity. This treatment also induced the expression of CK19, a marker of cells that are in a transitional differentiation stage. These results suggest that DNA methylation is a mechanism by which mammary epithelial differentiation is coordinated both at the tissue and cellular levels.
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Affiliation(s)
- Cedric Plachot
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN 47907-2026, USA
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Kelly TLJ, Li E, Trasler JM. 5-aza-2'-deoxycytidine induces alterations in murine spermatogenesis and pregnancy outcome. ACTA ACUST UNITED AC 2004; 24:822-30. [PMID: 14581508 DOI: 10.1002/j.1939-4640.2003.tb03133.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Because of the ability of cytidine analogues, such as 5-aza-2'-deoxycytidine, to incorporate into DNA and lead to decreases in DNA methylation, there has recently been renewed interest in using these drugs in anticancer therapy. To determine the effects of paternal 5-aza-2'-deoxycytidine treatment on spermatogenesis and progeny outcome in the mouse and whether effects are modulated by decreased levels of the predominant DNA methyltransferase, DNMT1, adult Dnmt1(+/+) and Dnmt1-deficient (Dnmt1(c/+)) male mice were treated with 5-aza-2'-deoxycytidine for 7 weeks, which resulted in dose-dependent decreases in testicular weight, an increase in histological abnormalities, and a decline in sperm counts, with no apparent effect on androgen status. Testes of Dnmt1(c/+) mice, however, were less severely affected by 5-aza-2'-deoxycytidine than were those of wild-type mice. The exposure of Dnmt1(+/+) male mice to even low doses of 5-aza-2'-deoxycytidine followed by mating elicited significantly reduced pregnancy rates and elevated preimplantation loss in females. Dnmt1 deficiency, however, protected against such drug-induced decreases in pregnancy rate but not preimplantation loss. Altered DNA methylation or DNMT1 activity may explain such adverse effects, because treatment resulted in dose-dependent decreases in the global methylation of sperm DNA. Thus, in the mouse, paternal administration of 5-aza-2'-deoxycytidine interferes with normal male germ cell development and results in reduced fertility, whereas lowering DNMT1 levels appears to partially protect the seminiferous epithelium from deleterious drug effects.
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Affiliation(s)
- Tamara L J Kelly
- Departments of Pediatrics, McGill University, and McGill University-Montreal Children's Hospital Research Institute, Montreal, Quebec, Canada
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Cisneros FJ, Branch S. 5-AZA-2'-deoxycytidine (5-AZA-CdR): a demethylating agent affecting development and reproductive capacity. J Appl Toxicol 2003; 23:115-20. [PMID: 12666156 DOI: 10.1002/jat.898] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The objective was to evaluate the effects of 5-AZA-2'-deoxycytidine (5-AZA-CdR) on postnatal development and reproductive capacity. Pregnant mice were administered 1 mg kg-1 5-AZA-CdR at gestation day 10. The body weights of F1 control and treated (in uterine-exposed) pups were recorded. To evaluate the reproductive capacity, 5-AZA-CdR F1 males and females were mated with control mice. The presence of plugs and the number of pregnancies were recorded. The 5-AZA-CdR F1 male mice were killed. Total body, testes and epididymis weights were recorded. Spermatid head counting, histological analyses and serum testosterone levels were performed. Body weights of 5-AZA-CdR F1 mice were statistically lower than controls (P < 0.01), with the females more strongly affected (P < 0.05). Male mating capacity appeared to be more adversely affected. Mating of 5-AZA-CdR F1 males with control females resulted in a lower pregnancy rate compared with control mating groups (P < 0.01). Gross testicular and epididymis weights were lower in 5-AZA-CdR F1 mice (P < 0.01). However, testicular and epididymis weights in these mice were higher than controls when correlated to body weight (P < 0.01). In 5-AZA-CdR F1 male mice, all measured reproductive parameters, including total number of spermatid heads per testis, are significantly lower (P < 0.01) than the controls except for the number of spermatid heads per milligram of testis.
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Affiliation(s)
- F Javier Cisneros
- Department of Anatomy, Physiological Sciences and Radiology, College of Veterinary Medicine, North Carolina State University, NC 27695, USA
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Rosen MB, Chernoff N. 5-Aza-2'-deoxycytidine-induced cytotoxicity and limb reduction defects in the mouse. TERATOLOGY 2002; 65:180-90. [PMID: 11948564 DOI: 10.1002/tera.10029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND 5-Aza-2'-deoxycytidine (dAZA), causes hindlimb phocomelia in CD-1 mice. Studies in our laboratory have examined the hypothesis that compound- induced changes in gene expression may uniquely affect hindlimb pattern formation. The present study tests the hypothesis that dAZA causes limb dysplasia by inducing cytotoxicity among rapidly proliferating cells in the limb bud mesenchyme. METHODS Pregnant CD-1 mice were given a teratogenic dose of dAZA (i.p.) at different times on GD 10 and fetuses evaluated for skeletal development in both sets of limbs by standard methods. Using general histology and BrdU immunohistochemistry, limb mesenchymal cell death and cell proliferation were then assessed in embryos at various times post dosing, shortly after initial limb bud outgrowth. The effect of dAZA on early limb chondrogenesis was also studied using Northern analysis of scleraxis and Alcian blue staining of whole mount limb buds. RESULTS Compound related hindlimb defects were not restricted to a specific set of skeletal elements but consisted of a range of temporally related limb anomalies. Modest defects of the radius were observed as well. These results are consistent with a general insult to the limb mesenchyme. Mesenchymal cell death and reduced cell proliferation were also observed in both sets of limbs. The timing and location of these effects indicate a role for cytotoxicity in the etiology of dAZA induced limb defects. These effects also agree with the greater teratogenicity of dAZA in the hindlimb because they were more pronounced in that limb. The expression of scleraxis, a marker of early chondrogenesis, was reduced 12 hr after dAZA exposure, a time coincident with maximal cell death, as was the subsequent emergence of Alcian blue stained long bone anlagen. CONCLUSIONS These findings support the hypothesis that cytotoxic changes in the limb bud mesenchyme during early limb outgrowth can induce the proximal limb truncations characteristic of phocomelia after dAZA administration.
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Affiliation(s)
- Mitchell B Rosen
- U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Reproductive Toxicology Division, Research Triangle Park, North Carolina 27711, USA.
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Doerksen T, Benoit G, Trasler JM. Deoxyribonucleic acid hypomethylation of male germ cells by mitotic and meiotic exposure to 5-azacytidine is associated with altered testicular histology. Endocrinology 2000; 141:3235-44. [PMID: 10965894 DOI: 10.1210/endo.141.9.7661] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Genomic methylation patterns originate during gametogenesis and are postulated to be involved in important developmental events, including gene regulation, embryogenesis, and genomic imprinting. In previous work, treatment of male rats with 5-azacytidine, a drug that blocks DNA methylation, resulted in abnormal embryo development when germ cells were exposed throughout spermatogenesis, encompassing mitotic, meiotic, and postmeiotic development, but not if they were only exposed postmeiotically. To explore the mechanisms underlying the effects of 5-azacytidine on sperm function, we determined the effects of the drug on testicular morphology, assessed whether exposure of meiotic spermatocytes resulted in abnormal pregnancy outcome, and examined the role of germ cell genomic demethylation in mediating the effects of 5-azacytidine on spermatogonia and spermatocytes. Male Sprague Dawley rats were treated three times a week with saline or 5-azacytidine (2.5 and 4.0 mg/kg) for 6 weeks (meiotic and postmeiotic germ cell exposure) and 11 weeks (mitotic, meiotic, and postmeiotic exposure). Six weeks of paternal treatment with the highest dose of 5-azacytidine resulted in an increase in preimplantation loss (corpora lutea minus implantation sites) without affecting testicular morphology or altering sperm DNA methylation levels. Eleven weeks of 5-azacytidine treatment at doses that cause preimplantation loss resulted in severe abnormalities of the seminiferous tubules, such as degeneration and loss of germ cells, atrophy of seminiferous tubules, presence of multinuclear giant cells, and sloughing of immature germ cells into the lumen, and a 22-29% decrease in genomic methylation levels in epididymal sperm. On closer evaluation of testicular histology using terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end-labeling detection in situ, both 6 and 11 weeks of 5-azacytidine treatment resulted in an increase over the control value in the number of apoptotic germ cells in the seminiferous tubules. Analysis of DNA methylation levels in isolated germ cells of treated males indicated that spermatogonia were more susceptible to the hypomethylating effects of 5-azacytidine than were spermatocytes. These studies provide evidence of an association between demethylation of germ cell DNA and alterations in testicular histology.
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Affiliation(s)
- T Doerksen
- Department of Pediatrics, McGill University, Montréal, Québec, Canada
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Chandrasekhar K, Raman R. De novo methylation of the proto-oncogene, c-fos, during development occurs step-wise and directionally in the laboratory mouse. Mol Reprod Dev 1997; 48:421-32. [PMID: 9364436 DOI: 10.1002/(sici)1098-2795(199712)48:4<421::aid-mrd2>3.0.co;2-s] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have analyzed the ontogenic initiation and maintenance of methylation of certain Hpall (m), Hhal (H), Hincll (Hc), and Sall (SI)-specific CpG sites in the coding region of the proto-oncogene, c-fos, through testicular cells, sperm, and fetal, neonatal, and adult somatic tissues. The results show that 1) sperm-derived methylated sites get demethylated in early development. However, unlike other studied genes, they remain so at least up to day 13.5 post coitum (pc); 2) de novo methylation proceeds unidirectionally in a step-wise, site-specific manner between m5-m3 sites; 3) the mature, tissue-specific, adult methylation pattern is established between day 0 and day 20 of neonatal development; 4) the Hc and SI sites (CGTCGAC), occurring at an interval of one nucleotide, are only partially methylated in all the tissues; and 5) m3 and H1 sites, which occur close to an Sp1 motif, escape methylation in most of the tissues. The present study on the embryonic gene, c-fos, thus provides a novel pattern of de novo methylation in development. Also, it suggests that close proximity of CpGs may prevent methylation.
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Affiliation(s)
- K Chandrasekhar
- Department of Zoology, Banaras Hindu University, Varanasi, India
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