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Banister CE, Koestler DC, Maccani MA, Padbury JF, Houseman EA, Marsit CJ. Infant growth restriction is associated with distinct patterns of DNA methylation in human placentas. Epigenetics 2011; 6:920-7. [PMID: 21758004 DOI: 10.4161/epi.6.7.16079] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The placenta acts not only as a conduit of nutrient and waste exchange between mother and developing fetus, but also functions as a regulator of the intrauterine environment. Recent work has identified changes in the expression of candidate genes, often through epigenetic alteration, which alter the placenta's function and impact fetal growth. In this study, we used the Illumina Infinium HumanMethylation27 BeadChip array to examine genome-wide DNA methylation patterns in 206 term human placentas. Semi-supervised recursively partitioned mixture modeling was implemented to identify specific patterns of placental DNA methylation that could differentially classify intrauterine growth restriction (IUGR) and small for gestational age (SGA) placentas from appropriate for gestational age (AGA) placentas, and these associations were validated in a masked testing series of samples. Our work demonstrates that patterns of DNA methylation in human placenta are reliably and significantly associated with infant growth and serve as a proof of principle that methylation status in the human term placenta can function as a marker for the intrauterine environment, and could potentially play a critical functional role in fetal development.
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Affiliation(s)
- Carolyn E Banister
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
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52
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Serman L, Dodig D. Impact of DNA methylation on trophoblast function. Clin Epigenetics 2011; 3:7. [PMID: 22414254 PMCID: PMC3303467 DOI: 10.1186/1868-7083-3-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 11/01/2011] [Indexed: 12/21/2022] Open
Abstract
The influence of epigenetics is evident in many fields of medicine today. This is also true in placentology, where versatile epigenetic mechanisms that regulate expression of genes have shown to have important influence on trophoblast implantation and placentation. Such gene regulation can be established in different ways and on different molecular levels, the most common being the DNA methylation. DNA methylation has been shown today as an important predictive component in assessing clinical prognosis of certain malignant tumors; in addition, it opens up new possibilities for non-invasive prenatal diagnosis utilizing cell-free fetal DNA methods. By using a well known demethylating agent 5-azacytidine in pregnant rat model, we have been able to change gene expression and, consequently, the processes of trophoblast differentiation and placental development. In this review, we describe how changes in gene methylation effect trophoblast development and placentation and offer our perspective on use of trophoblast epigenetic research for better understanding of not only placenta development but cancer cell growth and invasion as well.
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Affiliation(s)
- L Serman
- Department of Biology, School of Medicine, University of Zagreb, Zagreb, Croatia.
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53
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Macaulay EC, Weeks RJ, Andrews S, Morison IM. Hypomethylation of functional retrotransposon-derived genes in the human placenta. Mamm Genome 2011; 22:722-35. [PMID: 21874386 DOI: 10.1007/s00335-011-9355-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 07/29/2011] [Indexed: 11/25/2022]
Abstract
DNA hypomethylation is assumed to be a feature of the mammalian placenta; however, its role in regulating placental gene expression is not well defined. In this study, MeDIP and Sequenom MassARRAY were used to identify hypomethylated gene promoters in the human placenta. Among the genes identified, the hypomethylation of an alternative promoter for KCNH5 was found to be restricted to the placenta and chorion. Complete methylation of this promoter correlates with a silenced KCNH5 transcript in embryonic tissues, including the amnion. Unusually, this hypomethylated promoter and the alternative first exon are derived from a SINE (AluY) retrotransposon. Examination of additional retrotransposon-derived gene promoters in the placenta confirmed that retrotransposon hypomethylation permits the placenta-specific expression of these genes. Furthermore, the lineage-specific methylation displayed by KCNH5, INSL4, and ERVWE1 revealed that dichotomous methylation establishes differential retrotransposon silencing between the extra-embryonic and embryonic lineages. The hypomethylation of the retrotransposons that regulate these genes, each of which arose during recent primate evolution, is consistent with these genes having functional roles that are unique to the invasive haemochorial placentas of humans and recent primates.
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Affiliation(s)
- Erin C Macaulay
- Department of Pathology, Dunedin School of Medicine and National Research Centre for Growth and Development, University of Otago, New Zealand
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54
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Errasti-Murugarren E, Díaz P, Godoy V, Riquelme G, Pastor-Anglada M. Expression and distribution of nucleoside transporter proteins in the human syncytiotrophoblast. Mol Pharmacol 2011; 80:809-17. [PMID: 21825094 DOI: 10.1124/mol.111.071837] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The plasma membrane distribution and related biological activity of nucleoside transporter proteins (NTs) were investigated in human syncytiotrophoblast from term placenta using a variety of approaches, including nucleoside uptake measurements into vesicles from selected plasma membrane domains, NT immunohistochemistry, and subcellular localization (basal, heavy, and light apical membranes as well as raft-enriched membranes from the apical domain). In contrast with other epithelia, in this epithelium, we have identified the high-affinity pyrimidine-preferring human concentrative nucleoside transporter (hCNT) 1 as the only hCNT-type protein expressed at both the basal and apical membranes. hCNT1 localization in lipid rafts is also dependent on its subcellular localization in the apical plasma membrane, suggesting a complex cellular and regional expression. Overall, this result favors the view that the placenta is a pyrimidine-preferring nucleoside sink from both maternal and fetal sides, and hCNT1 plays a major role in promoting pyrimidine salvage and placental growth. This finding may be of pharmacological relevance, because hCNT1 is known to interact with anticancer nucleoside-derived drugs and other molecules, such as nicotine and caffeine, for which a great variety of harmful effects on placental and fetal development, including intrauterine growth retardation, have been reported.
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Affiliation(s)
- Ekaitz Errasti-Murugarren
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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55
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Fowden AL, Coan PM, Angiolini E, Burton GJ, Constancia M. Imprinted genes and the epigenetic regulation of placental phenotype. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 106:281-8. [PMID: 21108957 DOI: 10.1016/j.pbiomolbio.2010.11.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 11/06/2010] [Accepted: 11/10/2010] [Indexed: 10/18/2022]
Abstract
Imprinted genes are expressed in a parent-of-origin manner by epigenetic modifications that silence either the paternal or maternal allele. They are widely expressed in fetal and placental tissues and are essential for normal placental development. In general, paternally expressed genes enhance feto-placental growth while maternally expressed genes limit conceptus growth, consistent with the hypothesis that imprinting evolved in response to the conflict between parental genomes in the allocation of maternal resources to fetal growth. Using targeted deletion, uniparental duplication, loss of imprinting and transgenic approaches, imprinted genes have been shown to determine the transport capacity of the definitive mouse placenta by regulating its growth, morphology and transporter abundance. Imprinted genes in the placenta are also responsive to environmental challenges and adapt placental phenotype to the prevailing nutritional conditions, in part, by varying their epigenetic status. In addition, interplay between placental and fetal imprinted genes is important in regulating resource partitioning via the placenta both developmentally and in response to environmental factors. By balancing the opposing parental drives on resource allocation with the environmental signals of nutrient availability, imprinted genes, like the Igf2-H19 locus, may act as nutrient sensors and optimise the fetal acquisition of nutrients for growth. These genes, therefore, have a major role in the epigenetic regulation of placental phenotype with long term consequences for the developmental programming of adult health and disease.
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Affiliation(s)
- A L Fowden
- Department of Physiology, Development and Neuroscience, Downing Street, Cambridge CB23EG, United Kingdom.
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56
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An in vivo rat model to study epigenetic control of cell invasion. Med Hypotheses 2011; 76:407-9. [DOI: 10.1016/j.mehy.2010.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 10/27/2010] [Accepted: 11/04/2010] [Indexed: 11/20/2022]
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57
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Detection of global DNA methylation and paternally imprinted H19 gene methylation in preeclamptic placentas. Hypertens Res 2011; 34:655-61. [PMID: 21326306 DOI: 10.1038/hr.2011.9] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Preeclampsia (PE) is a severe hypertensive disorder associated with pregnancy; despite substantial research effort in the past several years, the etiology of PE is still unclear. The role of epigenetic factors in the etiology of PE, including DNA methylation, has been poorly characterized. In the present study, we investigated global DNA methylation as well as DNA methylation of the paternally imprinted H19 gene in preeclamptic placentas. Using 5-methylcytosine immunohistochemistry and Alu and LINE-1 repeat pyrosequencing, we found that the global DNA methylation level and the DNA (cytosine-5) methyltransferase 1 mRNA level were significantly higher in the early-onset preeclamptic placentas when compared with the normal controls. Data from methylation-sensitive high resolution melting demonstrated hypermethylation of the promoter region of the H19 gene, and results of real-time PCR showed decreased mRNA expression of H19 gene in the early-onset preeclamptic placentas as compared with the normal controls. Our results suggest that abnormal DNA methylation during placentation might be involved in the pathophysiology of PE, especially early-onset preeclampsia.
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58
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Novakovic B, Gordon L, Wong NC, Moffett A, Manuelpillai U, Craig JM, Sharkey A, Saffery R. Wide-ranging DNA methylation differences of primary trophoblast cell populations and derived cell lines: implications and opportunities for understanding trophoblast function. Mol Hum Reprod 2011; 17:344-53. [PMID: 21289002 DOI: 10.1093/molehr/gar005] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Difficulties associated with long-term culture of primary trophoblasts have proven to be a major hurdle in their functional characterization. In order to circumvent this issue, several model cell lines have been established over many years using a variety of different approaches. Due to their differing origins, gene expression profiles and behaviour in vitro, different model lines have been utilized to investigate specific aspects of trophoblast biology. However, generally speaking, the molecular mechanisms underlying functional differences remain unclear. In this study, we profiled genome-scale DNA methylation in primary first trimester trophoblast cells and seven commonly used trophoblast-derived cell lines in an attempt to identify functional pathways differentially regulated by epigenetic modification in these cells. We identified a general increase in DNA promoter methylation levels in four choriocarcinoma (CCA)-derived lines and transformed HTR-8/SVneo cells, including hypermethylation of several genes regularly seen in human cancers, while other differences in methylation were noted in genes linked to immune responsiveness, cell morphology, development and migration across the different cell populations. Interestingly, CCA-derived lines show an overall methylation profile more similar to unrelated solid cancers than to untransformed trophoblasts, highlighting the role of aberrant DNA methylation in CCA development and/or long-term culturing. Comparison of DNA methylation and gene expression in CCA lines and cytotrophoblasts revealed a significant contribution of DNA methylation to overall expression profile. These data highlight the variability in epigenetic state between primary trophoblasts and cell models in pathways underpinning a wide range of cell functions, providing valuable candidate pathways for future functional investigation in different cell populations. This study also confirms the need for caution in the interpretation of data generated from manipulation of such pathways in vitro.
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Affiliation(s)
- Boris Novakovic
- Cancer, Disease and Developmental Epigenetics Group, Murdoch Children's Research Institute, Royal Children's Hospital Melbourne, Parkville, Australia
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59
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Ghai S, Monga R, Mohanty TK, Chauhan MS, Singh D. Tissue-specific promoter methylation coincides with Cyp19 gene expression in buffalo (Bubalus bubalis) placenta of different stages of gestation. Gen Comp Endocrinol 2010; 169:182-9. [PMID: 20691690 DOI: 10.1016/j.ygcen.2010.07.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 07/20/2010] [Accepted: 07/21/2010] [Indexed: 11/15/2022]
Abstract
Aromatase is the key enzyme for estrogen biosynthesis and is encoded by Cyp19 gene. Placental cotyledons are the main site of Cyp19 gene expression during pregnancy. The present study was aimed to investigate if DNA methylation and thus epigenetic mechanisms play a potential role in stage-specific regulation of Cyp19 expression in placental cotyledons of pregnant water buffaloes (Bubalus bubalis). Significantly higher expression of Cyp19 gene (p<0.05) in placental cotyledons of early gestation period and post parturition period was found in comparison to mid-gestation placenta. Tissue-specific promoter driven transcript analyses showed that the change in expression was mainly due to change in the relative abundance of transcripts from exon I.1 while the transcripts from exon II showed comparatively less variation. Methylation analysis of 5 CpG dinucleotides of placenta-specific promoter I.1 and proximal promoter, PII showed hypo-methylation of PI.1 in early and term placenta while hyper-methylation in mid-placenta. However, PII was found to be hypomethylated in all the three tissues. In conclusion, result of the present study demonstrated that stage-specific methylation status of PI.1, the major promoter responsible for aromatase expression in buffalo placental cotyledons, coincides with the change in expression of Cyp19 gene in different stages of pregnancy.
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Affiliation(s)
- Sandeep Ghai
- Animal Biochemistry Division, National Dairy Research Institute, Karnal, Haryana, India
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60
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Maltepe E, Bakardjiev AI, Fisher SJ. The placenta: transcriptional, epigenetic, and physiological integration during development. J Clin Invest 2010; 120:1016-25. [PMID: 20364099 DOI: 10.1172/jci41211] [Citation(s) in RCA: 196] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The placenta provides critical transport functions between the maternal and fetal circulations during intrauterine development. Formation of this interface relies on coordinated interactions among transcriptional, epigenetic, and environmental factors. Here we describe these mechanisms in the context of the differentiation of placental cells (trophoblasts) and synthesize current knowledge about how they interact to generate a functional placenta. Developing an understanding of these pathways contributes to an improvement of our models for studying trophoblast biology and sheds light on the etiology of pregnancy complications and the in utero programming of adult diseases.
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Affiliation(s)
- Emin Maltepe
- Department of Pediatrics, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, 513 Parnassus Ave. HSE-1401, Box 1346, San Francisco, CA 94143-1346, USA.
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61
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Ng H, Novakovic B, Hiendleder S, Craig J, Roberts C, Saffery R. Distinct Patterns of Gene-Specific Methylation in Mammalian Placentas: Implications for Placental Evolution and Function. Placenta 2010; 31:259-68. [DOI: 10.1016/j.placenta.2010.01.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2009] [Revised: 01/07/2010] [Accepted: 01/12/2010] [Indexed: 11/16/2022]
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62
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Novakovic B, Wong NC, Sibson M, Ng HK, Morley R, Manuelpillai U, Down T, Rakyan VK, Beck S, Hiendleder S, Roberts CT, Craig JM, Saffery R. DNA methylation-mediated down-regulation of DNA methyltransferase-1 (DNMT1) is coincident with, but not essential for, global hypomethylation in human placenta. J Biol Chem 2010; 285:9583-9593. [PMID: 20071334 PMCID: PMC2843208 DOI: 10.1074/jbc.m109.064956] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The genome of extraembryonic tissue, such as the placenta, is hypomethylated relative to that in somatic tissues. However, the origin and role of this hypomethylation remains unclear. The DNA methyltransferases DNMT1, -3A, and -3B are the primary mediators of the establishment and maintenance of DNA methylation in mammals. In this study, we investigated promoter methylation-mediated epigenetic down-regulation of DNMT genes as a potential regulator of global methylation levels in placental tissue. Although DNMT3A and -3B promoters lack methylation in all somatic and extraembryonic tissues tested, we found specific hypermethylation of the maintenance DNA methyltransferase (DNMT1) gene and found hypomethylation of the DNMT3L gene in full term and first trimester placental tissues. Bisulfite DNA sequencing revealed monoallelic methylation of DNMT1, with no evidence of imprinting (parent of origin effect). In vitro reporter experiments confirmed that DNMT1 promoter methylation attenuates transcriptional activity in trophoblast cells. However, global hypomethylation in the absence of DNMT1 down-regulation is apparent in non-primate placentas and in vitro derived human cytotrophoblast stem cells, suggesting that DNMT1 down-regulation is not an absolute requirement for genomic hypomethylation in all instances. These data represent the first demonstration of methylation-mediated regulation of the DNMT1 gene in any system and demonstrate that the unique epigenome of the human placenta includes down-regulation of DNMT1 with concomitant hypomethylation of the DNMT3L gene. This strongly implicates epigenetic regulation of the DNMT gene family in the establishment of the unique epigenetic profile of extraembryonic tissue in humans.
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Affiliation(s)
- Boris Novakovic
- Developmental Epigenetics, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia; Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Nick C Wong
- Developmental Epigenetics, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | - Mandy Sibson
- Developmental Epigenetics, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | - Hong-Kiat Ng
- Developmental Epigenetics, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | - Ruth Morley
- Developmental Epigenetics, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | - Ursula Manuelpillai
- Monash Institute of Medical Research, Monash University, Clayton, Victoria 3168, Australia
| | - Thomas Down
- Wellcome Trust Cancer Research UK Gurdon Institute and Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, United Kingdom
| | - Vardhman K Rakyan
- Institute of Cell and Molecular Science, Barts and the London, London E1 2AT, United Kingdom
| | - Stephan Beck
- University College London Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Stefan Hiendleder
- JS Davies Epigenetics and Genetics Group, Animal Science, Adelaide, South Australia 5005, Australia
| | - Claire T Roberts
- School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Jeffrey M Craig
- Developmental Epigenetics, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia; Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Richard Saffery
- Developmental Epigenetics, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia; Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia.
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63
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Novakovic B, Sibson M, Ng HK, Manuelpillai U, Rakyan V, Down T, Beck S, Fournier T, Evain-Brion D, Dimitriadis E, Craig JM, Morley R, Saffery R. Placenta-specific methylation of the vitamin D 24-hydroxylase gene: implications for feedback autoregulation of active vitamin D levels at the fetomaternal interface. J Biol Chem 2009; 284:14838-48. [PMID: 19237542 PMCID: PMC2685665 DOI: 10.1074/jbc.m809542200] [Citation(s) in RCA: 183] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 02/20/2009] [Indexed: 11/21/2022] Open
Abstract
Plasma concentrations of biologically active vitamin D (1,25-(OH)(2)D) are tightly controlled via feedback regulation of renal 1alpha-hydroxylase (CYP27B1; positive) and 24-hydroxylase (CYP24A1; catabolic) enzymes. In pregnancy, this regulation is uncoupled, and 1,25-(OH)(2)D levels are significantly elevated, suggesting a role in pregnancy progression. Epigenetic regulation of CYP27B1 and CYP24A1 has previously been described in cell and animal models, and despite emerging evidence for a critical role of epigenetics in placentation generally, little is known about the regulation of enzymes modulating vitamin D homeostasis at the fetomaternal interface. In this study, we investigated the methylation status of genes regulating vitamin D bioavailability and activity in the placenta. No methylation of the VDR (vitamin D receptor) and CYP27B1 genes was found in any placental tissues. In contrast, the CYP24A1 gene is methylated in human placenta, purified cytotrophoblasts, and primary and cultured chorionic villus sampling tissue. No methylation was detected in any somatic human tissue tested. Methylation was also evident in marmoset and mouse placental tissue. All three genes were hypermethylated in choriocarcinoma cell lines, highlighting the role of vitamin D deregulation in this cancer. Gene expression analysis confirmed a reduced capacity for CYP24A1 induction with promoter methylation in primary cells and in vitro reporter analysis demonstrated that promoter methylation directly down-regulates basal promoter activity and abolishes vitamin D-mediated feedback activation. This study strongly suggests that epigenetic decoupling of vitamin D feedback catabolism plays an important role in maximizing active vitamin D bioavailability at the fetomaternal interface.
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Affiliation(s)
- Boris Novakovic
- Developmental Epigenetics, Murdoch Childrens Research Institute, Royal Children's Hospital, and Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia
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64
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Yamauchi H, Katayama KI, Ueno M, Kanemitsu H, Nam C, Mikami T, Saito A, Ishida Y, Uetsuka K, Doi K, Ohmach Y, Nakayama H. Etoposide induces TRP53-dependent apoptosis and TRP53-independent cell cycle arrest in trophoblasts of the developing mouse placenta. Biol Reprod 2008; 80:813-22. [PMID: 19109225 DOI: 10.1095/biolreprod.108.069419] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Abnormal regulation of placental apoptosis and proliferation has been implicated in placental disorders. Recently, several DNA-damaging agents were reported to induce excessive apoptosis and reduce cell proliferation in the placenta; however, the molecular pathways of these toxic effects on the placenta are unclear. The aim of the present study was to determine the involvement of TRP53, a tumor suppressor that mediates cellular responses to DNA damage, in the induction of apoptosis and cell cycle arrest in the developing placenta. For this purpose, we treated pregnant mice on Day 12 of gestation with 10 mg/kg of etoposide and 5-Gy gamma irradiation, potent inducers of DNA damage. We found an increase in the number of trophoblastic apoptoses 8 and 24 h after etoposide injection and 6 and 24 h after irradiation in the placental labyrinth zone. The number of mitoses and DNA syntheses in trophoblasts decreased after treatment. The accumulation and phosphorylation of TRP53 protein were detected 8 and 6 h after etoposide injection and irradiation, respectively. In Trp53-deficient placentas, the induction of etoposide-induced trophoblastic apoptosis is abrogated, while the reduction of proliferation occurred similarly as in wild-type placentas. CDC2A, a regulator of G2/M progression, was inactivated by phosphorylation after etoposide injection and irradiation, suggesting that the cell cycle was arrested at the G2/M border by treatment. Our study demonstrated that etoposide injection induced TRP53-dependent apoptosis and TRP53-independent cell cycle arrest in labyrinthine trophoblasts, providing insights into the molecular pathway of placental disorders.
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Affiliation(s)
- Hirofumi Yamauchi
- Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
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65
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Novakovic B, Rakyan V, Ng HK, Manuelpillai U, Dewi C, Wong NC, Morley R, Down T, Beck S, Craig JM, Saffery R. Specific tumour-associated methylation in normal human term placenta and first-trimester cytotrophoblasts. Mol Hum Reprod 2008; 14:547-54. [PMID: 18708652 DOI: 10.1093/molehr/gan046] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Human placentation displays many similarities with tumourigenesis, including rapid cell division, migration and invasion, overlapping gene expression profiles and escape from immune detection. Recent data have identified promoter methylation in the Ras association factor and adenomatous polyposis coli tumour suppressor genes as part of this process. However, the extent of tumour-associated methylation in the placenta remains unclear. Using whole genome methylation data as a starting point, we have examined this phenomenon in placental tissue. We found no evidence for methylation of the majority of common tumour suppressor genes in term placentas, but identified methylation in several genes previously described in some human tumours. Notably, promoter methylation of four independent negative regulators of Wnt signalling has now been identified in human placental tissue and purified trophoblasts. Methylation is present in baboon, but not in mouse placentas. This supports a role for elevated Wnt signalling in primate trophoblast invasiveness and placentation. Examination of invasive choriocarcinoma cell lines revealed altered methylation patterns consistent with a role of methylation change in gestational trophoblastic disease. This distinct pattern of tumour-associated methylation implicates a coordinated series of epigenetic silencing events, similar to those associated with some tumours, in the distinct features of normal human placental invasion and function.
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Affiliation(s)
- B Novakovic
- Developmental Epigenetics Research, Murdoch Children's Research Institute, Royal Children's Hospital, VIC 3052, Australia
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