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Jin Y, Vakili H, Liu SY, Menticoglou S, Bock ME, Cattini PA. Chromosomal architecture and placental expression of the human growth hormone gene family are targeted by pre-pregnancy maternal obesity. Am J Physiol Endocrinol Metab 2018; 315:E435-E445. [PMID: 29763375 DOI: 10.1152/ajpendo.00042.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The human (h) placental lactogenic hormone chorionic somatomammotropin (CS) is highly produced during pregnancy and acts as a metabolic adaptor in response to maternal insulin resistance. Maternal obesity can exacerbate this "resistance", and a >75% decrease in CS RNA levels was observed in term placentas from obese vs. lean women. The genes coding for hCS ( hCS-A and hCS-B) and placental growth hormone ( hGH-V) as well as the hCS-L pseudogene and pituitary growth hormone (GH) gene ( hGH-N) are located at a single locus on chromosome 17. Three remote hypersensitive sites (HS III-V) located >28 kb upstream of hGH-N as well as local hCS gene promoter and enhancer regions are implicated in hCS gene expression. A placenta-specific chromosomal architecture, including interaction between HS III-V and hCS but not hGH gene promoters, was detected in placentas from lean women (BMI <25 kg/m2) by using the chromosome conformation capture assay. This architecture was disrupted by pre-pregnancy maternal obesity (BMI >35 kg/m2), resulting in a predominant interaction between HS III and the hGH-N promoter, which was also observed in nonplacental tissues. This was accompanied by a decrease in hCS levels, which was consistent with reduced RNA polymerase II and CCAAT/enhancer-binding protein-β association with individual hCS promoter and enhancer sequences, respectively. Thus, pre-pregnancy maternal obesity disrupts the placental hGH/CS gene locus chromosomal architecture. However, based on data from obese women who develop GDM, insulin treatment partially recapitulates the chromosomal architecture seen in lean women and positively affects hCS production, presumably facilitating prolactin receptor-related signaling by hCS.
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Affiliation(s)
- Yan Jin
- Department of Physiology and Pathophysiology, University of Manitoba , Winnipeg, Manitoba , Canada
| | - Hana Vakili
- Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute, St. Michael's Hospital , Toronto, Ontario , Canada
| | - Song Yan Liu
- Department of Biochemistry and Medical Genetics and College of Pharmacy, University of Manitoba , Winnipeg, Manitoba , Canada
| | - Savas Menticoglou
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Manitoba , Winnipeg, Manitoba , Canada
| | - Margaret E Bock
- Department of Physiology and Pathophysiology, University of Manitoba , Winnipeg, Manitoba , Canada
| | - Peter A Cattini
- Department of Physiology and Pathophysiology, University of Manitoba , Winnipeg, Manitoba , Canada
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Cattini PA, Bock ME, Jin Y, Zanghi JA, Vakili H. A useful model to compare human and mouse growth hormone gene chromosomal structure, expression and regulation, and immune tolerance of human growth hormone analogues. Growth Horm IGF Res 2018; 42-43:58-65. [PMID: 30227383 DOI: 10.1016/j.ghir.2018.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 08/15/2018] [Accepted: 09/06/2018] [Indexed: 11/25/2022]
Abstract
Human (h) pituitary growth hormone (GH) is both physiologically and clinically important. GH reaches its highest circulatory levels in puberty, where it contributes to energy homeostasis and somatogenic growth. GH also helps to maintain tissues and organs and, thus, health and homeostasis. A reduction in the rate of hGH production begins in middle age but if GH insufficiency occurs this may result in tissue degenerative and metabolic diseases. As a consequence, hGH is prescribed under conditions of GH deficiency and, because of its lipolytic activity, stimulation of hGH release has also been used to treat obesity. However, studies of normal GH production and particularly synthesis versus secretion are not feasible in humans as they require sampling normal pituitaries from living subjects. Furthermore, human (or primate) GH structure and, as such, regulation and potential function, is distinct from non-primate rodent GH. As a result, most information about hGH regulation comes from measurements of secreted levels of GH in humans. Thus, partially humanized hGH transgenic mice, generated containing fragments of human chromosome 17 that include the intact hGH gene locus and many thousands of flanking base pairs as well as the endogenous mouse (m) GH gene provide a potentially useful model. Here we review this mouse model in terms of its ability to allow comparison of hGH versus mGH gene expression, and specifically: (i) GH locus structure as well as regulated and rhythmic expression; (ii) their ability to model a clinical assessment of hGH production in response to overeating and hyperinsulinemia as well as a possible effect of exercise, and (iii) their hGH-related immune tolerance and thus potential for testing hGH-related analogue immunogenicity.
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Affiliation(s)
- Peter A Cattini
- Department of Physiology & Pathophysiology, University of Manitoba, Manitoba, Canada.
| | - Margaret E Bock
- Department of Physiology & Pathophysiology, University of Manitoba, Manitoba, Canada
| | - Yan Jin
- Department of Physiology & Pathophysiology, University of Manitoba, Manitoba, Canada
| | | | - Hana Vakili
- Department of Pathology, University of Texas Southwestern Medical Center, TX, USA
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Tsai YC, Cooke NE, Liebhaber SA. Long-range looping of a locus control region drives tissue-specific chromatin packing within a multigene cluster. Nucleic Acids Res 2016; 44:4651-64. [PMID: 26893355 PMCID: PMC4889918 DOI: 10.1093/nar/gkw090] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 02/03/2016] [Indexed: 12/12/2022] Open
Abstract
The relationships of higher order chromatin organization to mammalian gene expression remain incompletely defined. The human Growth Hormone (hGH) multigene cluster contains five gene paralogs. These genes are selectively activated in either the pituitary or the placenta by distinct components of a remote locus control region (LCR). Prior studies have revealed that appropriate activation of the placental genes is dependent not only on the actions of the LCR, but also on the multigene composition of the cluster itself. Here, we demonstrate that the hGH LCR 'loops' over a distance of 28 kb in primary placental nuclei to make specific contacts with the promoters of the two GH genes in the cluster. This long-range interaction sequesters the GH genes from the three hCS genes which co-assemble into a tightly packed 'hCS chromatin hub'. Elimination of the long-range looping, via specific deletion of the placental LCR components, triggers a dramatic disruption of the hCS chromatin hub. These data reveal a higher-order structural pathway by which long-range looping from an LCR impacts on local chromatin architecture that is linked to tissue-specific gene regulation within a multigene cluster.
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Affiliation(s)
- Yu-Cheng Tsai
- Department of Genetics and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA 19104, USA
| | - Nancy E Cooke
- Department of Genetics and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA 19104, USA
| | - Stephen A Liebhaber
- Department of Genetics and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA 19104, USA
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Krause BJ, Castro-Rodríguez JA, Uauy R, Casanello P. [General concepts of epigenetics: Projections in paediatrics]. ACTA ACUST UNITED AC 2016; 87:4-10. [PMID: 26872716 DOI: 10.1016/j.rchipe.2015.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/16/2015] [Accepted: 12/19/2015] [Indexed: 12/24/2022]
Abstract
Current evidence supports the notion that alterations in intrauterine growth and during the first years of life have a substantial effect on the risk for the development of chronic disease, which in some cases is even higher than those due to genetic factors. The persistence and reproducibility of the phenotypes associated with altered early development suggest the participation of mechanisms that would record environmental cues, generating a cellular reprogramming (i.e., epigenetic mechanisms). This review is an introduction to a series of five articles focused on the participation of epigenetic mechanisms in the development of highly prevalent chronic diseases (i.e., cardiovascular, metabolic, asthma/allergies and cancer) and their origins in the foetal and neonatal period. This series of articles aims to show the state of the art in this research area and present the upcoming clues and challenges, in which paediatricians have a prominent role, developing strategies for the prevention, early detection and follow-up.
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Affiliation(s)
- Bernardo J Krause
- División de Pediatría, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - José A Castro-Rodríguez
- División de Pediatría, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Ricardo Uauy
- División de Pediatría, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Paola Casanello
- División de Pediatría, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile; División de Obstetricia y Ginecología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Ganguly E, Bock ME, Cattini PA. Expression of Placental Members of the Human Growth Hormone Gene Family Is Increased in Response to Sequential Inhibition of DNA Methylation and Histone Deacetylation. Biores Open Access 2015; 4:446-56. [PMID: 26634190 PMCID: PMC4657510 DOI: 10.1089/biores.2015.0036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The genes coding for human (h) chorionic somatomammotropin (CS), hCS-A and hCS-B, and placental growth hormone (GH-V), hGH-V, are located at a single locus on chromosome 17. Efficient expression of these placental genes has been linked to local regulatory (5′ P and 3′ enhancer) sequences and a remote locus control region (LCR), in part, through gene transfer in placental and nonplacental tumor cells. However, low levels of endogenous hCS/GH-V transcripts are reported in the same cells compared with term placenta, suggesting that chromatin structure, or regulatory region accessibility, versus transcription factor availability contributes to the relatively low levels. To assess individual hCS-A, CS-B, and GH-V gene expression in placental and nonplacental tumor cells and the effect of increasing chromatin accessibility by inhibiting DNA methylation and histone deacetylation using 5-aza-2′-deoxycytidine (azadC) and trichostatin A (TSA). Low levels of hCS-A, CS-B, and GH-V were detected in placental and nonplacental tumor cells compared with term placenta. A significant >5-fold increase in activity was seen in placental, but not nonplacental, cells transfected with hybrid hCS promoter luciferase genes containing 3′ enhancer sequences. Pretreatment of placental JEG-3 cells with azadC resulted in a >10-fold increase in hCS-A, CS-B, and GH-V RNA levels with TSA treatment compared with TSA treatment alone. This effect was specific as reversing the treatment regimen did not have the same effect. An assessment of hyperacetylated H3/H4 in JEG-3 cells treated with azadC and TSA versus TSA alone revealed significant increases consistent with a more open chromatin structure, including the hCS 3′ enhancer sequences and LCR. These observations suggest that accessibility of remote and local regulatory regions required for efficient placental hGH/CS expression can be restricted by DNA methylation and histone acetylation status. This includes restricting access of the hCS 3′ enhancer sequences to available placental enhancer transcription factors.
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Affiliation(s)
- Esha Ganguly
- Department of Physiology and Pathophysiology, University of Manitoba , Winnipeg, Canada
| | - Margaret E Bock
- Department of Physiology and Pathophysiology, University of Manitoba , Winnipeg, Canada
| | - Peter A Cattini
- Department of Physiology and Pathophysiology, University of Manitoba , Winnipeg, Canada
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Different epigenetic states define syncytiotrophoblast and cytotrophoblast nuclei in the trophoblast of the human placenta. Placenta 2015; 36:796-802. [PMID: 26008948 DOI: 10.1016/j.placenta.2015.05.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 04/15/2015] [Accepted: 05/05/2015] [Indexed: 12/31/2022]
Abstract
INTRODUCTION The syncytiotrophoblast (STB) epithelial covering of the villous tree in the human placenta is a multi-nucleated syncytium that is sustained by continuous incorporation of differentiating cytotrophoblast (CTB) cells. STB nuclei display a variety of morphologies, but are generally more condensed in comparison to CTB nuclei. Here, we consider whether this condensation is a feature of epigenetic regulation of chromatin structure. METHODS Semi-quantitative immunohistochemical investigations of a panel of histone modifications were performed to determine the relative proportions in CTB and STB nuclear populations. We also investigated the patterns of DNA methylation and distribution of DNA methyltransferases enzymes in these populations. RESULTS Unexpectedly DNA methylation, and H3K9me3 and H3K27me3, which are modifications associated with heterochromatin, are present at lower levels in STB nuclei compared to CTB, despite the intensive condensation in the former nuclear population and the progenitor state of the latter. By contrast, STB nuclei are enriched for H4K20me3, which is also associated with repressive states. 5'hydroxymethylcytosine immunoreactivity is higher in STB, with intense staining observed in the highly condensed nuclei within syncytial knots. DISCUSSION Cell-type specific epigenetic states exist within the trophoblast populations potentially regulating their different functions and developmental properties and suggesting non-canonical epigenetic states associated with the properties of these cells.
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Characterization of the humanTCAM1Ppseudogene and its activation by a potential dual promoter-enhancer: Comparison with a protein-coding mouse orthologue. FEBS Lett 2015; 589:540-7. [DOI: 10.1016/j.febslet.2015.01.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/14/2015] [Accepted: 01/15/2015] [Indexed: 11/17/2022]
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Kurihara M, Shiraishi A, Satake H, Kimura AP. A conserved noncoding sequence can function as a spermatocyte-specific enhancer and a bidirectional promoter for a ubiquitously expressed gene and a testis-specific long noncoding RNA. J Mol Biol 2014; 426:3069-93. [PMID: 25020229 DOI: 10.1016/j.jmb.2014.06.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 12/13/2022]
Abstract
Tissue-specific gene expression is tightly regulated by various elements such as promoters, enhancers, and long noncoding RNAs (lncRNAs). In the present study, we identified a conserved noncoding sequence (CNS1) as a novel enhancer for the spermatocyte-specific mouse testicular cell adhesion molecule 1 (Tcam1) gene. CNS1 was located 3.4kb upstream of the Tcam1 gene and associated with histone H3K4 mono-methylation in testicular germ cells. By the in vitro reporter gene assay, CNS1 could enhance Tcam1 promoter activity only in GC-2spd(ts) cells, which were derived from mouse spermatocytes. When we integrated the 6.9-kb 5'-flanking sequence of Tcam1 with or without a deletion of CNS1 linked to the enhanced green fluorescent protein gene into the chromatin of GC-2spd(ts) cells, CNS1 significantly enhanced Tcam1 promoter activity. These results indicate that CNS1 could function as a spermatocyte-specific enhancer. Interestingly, CNS1 also showed high bidirectional promoter activity in the reporter assay, and consistent with this, the Smarcd2 gene and lncRNA, designated lncRNA-Tcam1, were transcribed from adjacent regions of CNS1. While Smarcd2 was ubiquitously expressed, lncRNA-Tcam1 expression was restricted to testicular germ cells, although this lncRNA did not participate in Tcam1 activation. Ubiquitous Smarcd2 expression was correlated to CpG hypo-methylation of CNS1 and partially controlled by Sp1. However, for lncRNA-Tcam1 transcription, the strong association with histone acetylation and histone H3K4 tri-methylation also appeared to be required. The present data suggest that CNS1 is a spermatocyte-specific enhancer for the Tcam1 gene and a bidirectional promoter of Smarcd2 and lncRNA-Tcam1.
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Affiliation(s)
- Misuzu Kurihara
- Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Akira Shiraishi
- Suntory Foundation for Life Sciences, Bioorganic Research Institute, Osaka 618-8503, Japan
| | - Honoo Satake
- Suntory Foundation for Life Sciences, Bioorganic Research Institute, Osaka 618-8503, Japan
| | - Atsushi P Kimura
- Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan; Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
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Tissue factor expression and methylation regulation in differentiation of embryonic stem cells into trophoblast. ASIAN PAC J TROP MED 2014; 7:557-61. [DOI: 10.1016/s1995-7645(14)60093-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 03/15/2014] [Accepted: 06/15/2014] [Indexed: 11/22/2022] Open
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Tsai YC, Cooke NE, Liebhaber SA. Tissue specific CTCF occupancy and boundary function at the human growth hormone locus. Nucleic Acids Res 2014; 42:4906-21. [PMID: 24561805 PMCID: PMC4005687 DOI: 10.1093/nar/gku139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The robust and tissue-specific activation of the human growth hormone (hGH) gene cluster in the pituitary and placenta constitutes an informative model for analysis of gene regulation. The five-gene hGH cluster is regulated by two partially overlapping sets of DNase I hypersensitive sites (HSs) that constitute the pituitary (HSI, II, III and V) and placental (HSIII, IV, and V) locus control regions (LCRs). The single placenta-specific LCR component, HSIV, is located at −30 kb to the cluster. Here we generate a series of hGH/BAC transgenes specifically modified to identify structural features of the hGH locus required for its appropriate placental expression. We find that placental specificity is dependent on the overall multigene configuration of the cluster whereas the distance between the cluster and its LCR impacts the level of placental expression. We further observe that a major function of the placental hGH LCR is to insulate the transgene locus from site-of-integration effects. This insulation activity is linked to placenta-specific occupancy of the chromatin architectural protein, CTCF, at HSIV. These data reveal a remarkable combination of structural configurations and regulatory determinants that must work in concert to insure robust and tightly controlled expression from a complex multigene locus.
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Affiliation(s)
- Yu-Cheng Tsai
- Departments of Genetics and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Li J, Wang W, Liu C, Wang W, Li W, Shu Q, Chen ZJ, Sun K. Critical role of histone acetylation by p300 in human placental 11β-HSD2 expression. J Clin Endocrinol Metab 2013; 98:E1189-97. [PMID: 23714681 DOI: 10.1210/jc.2012-4291] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Fetal overexposure to glucocorticoids leads to growth restriction. Optimal fetal glucocorticoid level is ensured by the expression of cortisol-inactivating enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) in placental syncytiotrophoblasts. The transcription factor selective promoter factor 1 (Sp1) is known to up-regulate 11β-HSD2 expression in the presence of enhanced histone acetylation in syncytiotrophoblasts, but the mechanisms underlying histone acetylation remain unknown. OBJECTIVES The role of p300 in histone acetylation associated with 11β-HSD2 expression in syncytiotrophoblasts was investigated. DESIGN Distribution of p300 in human placenta was studied with immunohistochemistry. The role of p300 in histone-3 (H3) acetylation in association with 11β-HSD2 expression was investigated in cultured primary human placental trophoblasts in the presence of small interfering RNA (siRNA)-mediated knockdown of p300, p300 inhibitor C646, or p300 overexpression. The interaction of Sp1 and p300 was studied with chromatin immunoprecipitation and coimmunoprecipitation. RESULTS Intense staining of p300 was found in the nuclei of trophoblasts. Levels of p300 and acetyl H3K9 and H3K27 associated with 11β-HSD2 promoter were increased in the course of syncytialization and by cAMP pathway activation. Chromatin immunoprecipitation and coimmunoprecipitation revealed p300 and Sp1 on 11β-HSD2 promoter and in the same protein complex in the syncytiotrophoblasts. Overexpression of p300 enhanced 11β-HSD2 expression, which was attenuated by Sp1 knockdown, whereas p300 knockdown and C646 reduced both basal and cAMP-stimulated acetylation of H3K9 and H3K27 associated with 11β-HSD2 expression. CONCLUSIONS Interaction of p300 with Sp1 plays a crucial role in histone acetylation associated with 11β-HSD2 expression in syncytiotrophoblasts, which may have important implications in the establishment of the placental glucocorticoid barrier in gestation.
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Affiliation(s)
- Jianneng Li
- School of Life Sciences, Fudan University, Shanghai 200433, China
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Vakili H, Jin Y, Menticoglou S, Cattini PA. CCAAT-enhancer-binding protein β (C/EBPβ) and downstream human placental growth hormone genes are targets for dysregulation in pregnancies complicated by maternal obesity. J Biol Chem 2013; 288:22849-61. [PMID: 23782703 DOI: 10.1074/jbc.m113.474999] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human chorionic somatomammotropin (CS) and placental growth hormone variant (GH-V) act as metabolic adaptors in response to maternal insulin resistance, which occurs in "normal" pregnancy. Maternal obesity can exacerbate this "resistance," suggesting that CS, GH-V, or transcription factors that regulate their production might be targets. The human CS genes, hCS-A and hCS-B, flank the GH-V gene. A significant decrease in pre-term placental CS/GH-V RNA levels was observed in transgenic mice containing the CS/GH-V genes in a model of high fat diet (HFD)-induced maternal obesity. Similarly, a decrease in CS/GH-V RNA levels was detected in term placentas from obese (body mass index (BMI) ≥ 35 kg/m(2)) versus lean (BMI 20-25 kg/m(2)) women. A specific decrease in transcription factor CCAAT-enhancer-binding protein β (C/EBPβ) RNA levels was also seen with obesity; C/EBPβ is required for mouse placenta development and is expressed, like CS and GH-V, in syncytiotrophoblasts. Binding of C/EBPβ to the CS gene downstream enhancer regions, which by virtue of their position distally flank the GH-V gene, was reduced in placenta chromatin from mice on a HFD and in obese women; a corresponding decrease in RNA polymerase II associated with CS/GH-V promoters was also observed. Detection of decreased endogenous CS/GH-V RNA levels in human placental tumor cells treated with C/EBPβ siRNA is consistent with a direct effect. These data provide evidence for CS/GH-V dysregulation in acute HFD-induced obesity in mouse pregnancy and chronic obesity in human pregnancy and implicate C/EBPβ, a factor associated with CS regulation and placental development.
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Affiliation(s)
- Hana Vakili
- Department of Physiology, Division of Endocrinology and Metabolic Disease, University of Manitoba, Winnipeg R3E 0J9, Canada
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Yoo EJ, Cooke NE, Liebhaber SA. Identification of a secondary promoter within the human B cell receptor component gene hCD79b. J Biol Chem 2013; 288:18353-65. [PMID: 23649625 DOI: 10.1074/jbc.m113.461988] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The human B cell-specific protein, CD79b (also known as Igβ and B29) constitutes an essential signal transduction component of the B cell receptor. Although its function is central to the triggering of B cell terminal differentiation in response to antigen stimulation, the transcriptional determinants that control CD79b gene expression remain poorly defined. In the present study, we explored these determinants using a series of hCD79b transgenic mouse models. Remarkably, we observed that the previously described hCD79b promoter along with its associated enhancer elements and first exon could be deleted without appreciable loss of hCD79b transcriptional activity or tissue specificity. In this deletion setting, a secondary promoter located within exon 2 maintained full levels and specificity of hCD79b transcription. Of note, this secondary promoter was also active, albeit at lower levels, in the wild-type hCD79b locus. The activity of the secondary promoter was dependent on the action(s) of a conserved sequence element mapping to a chromatin DNase I hypersensitive site located within intron 1. mRNA generated from this secondary promoter is predicted to encode an Igβ protein lacking a signal sequence and thus unable to serve normal B cell receptor function. Although the physiologic role of the hCD79b secondary promoter and its encoded protein remain unclear, the current data suggest that it has the capacity to play a role in normal as well as pathologic states in B cell proliferation and function.
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Affiliation(s)
- Eung Jae Yoo
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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PSG gene expression is up-regulated by lysine acetylation involving histone and nonhistone proteins. PLoS One 2013; 8:e55992. [PMID: 23418492 PMCID: PMC3572148 DOI: 10.1371/journal.pone.0055992] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 01/04/2013] [Indexed: 11/25/2022] Open
Abstract
Background Lysine acetylation is an important post-translational modification that plays a central role in eukaryotic transcriptional activation by modifying chromatin and transcription-related factors. Human pregnancy-specific glycoproteins (PSG) are the major secreted placental proteins expressed by the syncytiotrophoblast at the end of pregnancy and represent early markers of cytotrophoblast differentiation. Low PSG levels are associated with complicated pregnancies, thus highlighting the importance of studying the mechanisms that control their expression. Despite several transcription factors having been implicated as key regulators of PSG gene family expression; the role of protein acetylation has not been explored. Methodology/Principal Findings Here, we explored the role of acetylation on PSG gene expression in the human placental-derived JEG-3 cell line. Pharmacological inhibition of histone deacetylases (HDACs) up-regulated PSG protein and mRNA expression levels, and augmented the amount of acetylated histone H3 associated with PSG 5′regulatory regions. Moreover, PSG5 promoter activation mediated by Sp1 and KLF6, via the core promoter element motif (CPE, −147/−140), was markedly enhanced in the presence of the HDAC inhibitor trichostatin A (TSA). This effect correlated with an increase in Sp1 acetylation and KLF6 nuclear localization as revealed by immunoprecipitation and subcellular fractionation assays. The co-activators PCAF, p300, and CBP enhanced Sp1-dependent PSG5 promoter activation through their histone acetylase (HAT) function. Instead, p300 and CBP acetyltransferase domain was dispensable for sustaining co-activation of PSG5 promoter by KLF6. Conclusions/Significance Results are consistent with a regulatory role of lysine acetylation on PSG expression through a relaxed chromatin state and an increase in the transcriptional activity of Sp1 and KLF6 following an augmented Sp1 acetylation and KLF6 nuclear localization.
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Epigenetic modifications unlock the milk protein gene loci during mouse mammary gland development and differentiation. PLoS One 2013; 8:e53270. [PMID: 23301053 PMCID: PMC3534698 DOI: 10.1371/journal.pone.0053270] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 11/27/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Unlike other tissues, development and differentiation of the mammary gland occur mostly after birth. The roles of systemic hormones and local growth factors important for this development and functional differentiation are well-studied. In other tissues, it has been shown that chromatin organization plays a key role in transcriptional regulation and underlies epigenetic regulation during development and differentiation. However, the role of chromatin organization in mammary gland development and differentiation is less well-defined. Here, we have studied the changes in chromatin organization at the milk protein gene loci (casein, whey acidic protein, and others) in the mouse mammary gland before and after functional differentiation. METHODOLOGY/PRINCIPAL FINDINGS Distal regulatory elements within the casein gene cluster and whey acidic protein gene region have an open chromatin organization after pubertal development, while proximal promoters only gain open-chromatin marks during pregnancy in conjunction with the major induction of their expression. In contrast, other milk protein genes, such as alpha-lactalbumin, already have an open chromatin organization in the mature virgin gland. Changes in chromatin organization in the casein gene cluster region that are present after puberty persisted after lactation has ceased, while the changes which occurred during pregnancy at the gene promoters were not maintained. In general, mammary gland expressed genes and their regulatory elements exhibit developmental stage- and tissue-specific chromatin organization. CONCLUSIONS/SIGNIFICANCE A progressive gain of epigenetic marks indicative of open/active chromatin on genes marking functional differentiation accompanies the development of the mammary gland. These results support a model in which a chromatin organization is established during pubertal development that is then poised to respond to the systemic hormonal signals of pregnancy and lactation to achieve the full functional capacity of the mammary gland.
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Novakovic B, Saffery R. The ever growing complexity of placental epigenetics – Role in adverse pregnancy outcomes and fetal programming. Placenta 2012; 33:959-70. [DOI: 10.1016/j.placenta.2012.10.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 10/02/2012] [Accepted: 10/06/2012] [Indexed: 02/01/2023]
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Smith R, Paul J, Maiti K, Tolosa J, Madsen G. Recent advances in understanding the endocrinology of human birth. Trends Endocrinol Metab 2012; 23:516-23. [PMID: 22682480 DOI: 10.1016/j.tem.2012.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 04/23/2012] [Accepted: 05/01/2012] [Indexed: 02/06/2023]
Abstract
The timing of human birth has a crucial impact upon the survival of the fetus. New knowledge on the regulation of human birth includes the role of endogenous retroviruses in the formation of the syncytiotrophoblast cells and consequently the secretion of corticotrophin releasing hormone, a hormone linked to gestational length determination. miRNAs have been identified that mediate progesterone withdrawal at labor by suppressing progesterone-induced transcription factors. Progress has also been made in understanding how the contractile machinery of the uterine myocytes is activated at labor and the role of small heat-shock proteins in this process. From this work, new therapeutic targets have been identified that may be used to regulate the onset of labor and improve neonatal mortality.
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Affiliation(s)
- Roger Smith
- Mothers and Babies Research Centre, Faculty of Health, University of Newcastle, Callaghan, NSW 2308, Australia.
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18
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Abstract
SIGNIFICANCE Epigenetic modifications are key processes in understanding normal human development and are largely responsible for the myriad cell and tissue types that originate from a single-celled fertilized ovum. The three most common processes involved in bringing about epigenetic changes are DNA methylation, histone modification, and miRNA effects. There are critical periods in the development of the zygote, the embryo, and the fetus where in the organism is most susceptible to epigenetic influences because of normal demethylation and de novo methylation processes that occur in the womb. RECENT ADVANCES A number of epigenetic modifications of normal growth patterns have been recognized, leading to altered development and disease states in the mammalian fetus and infant. 'Fetal programming' due to these epigenetic changes has been implicated in pathogenesis of adult-onset disease such as hypertension, diabetes, and cardiovascular disease. There may also be transgenerational effects of such epigenetic modifications. CRITICAL ISSUES The impact of environmental agents and endogenous factors such as stress at critical periods of infant development has immediate, life-long and even multi-generational effects. Both the timing and the degree of insult may be important. Understanding these influences may help prevent onset of disease and promote normal growth. FUTURE DIRECTIONS Use of one-carbon metabolism modifying agents such as folic acid during critical periods of epigenetic modulation may have significant clinical impact. Their use as therapeutic agents in targeted epigenetic modulation of genes may be the new frontier for clinical therapeutics.
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Affiliation(s)
- Naveed Hussain
- Division of Neonatal Pediatrics, Connecticut Children's NICU, University of Connecticut Health Center, Farmington, Connecticut 06030-2948, USA.
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19
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Männik J, Vaas P, Rull K, Teesalu P, Laan M. Differential placental expression profile of human Growth Hormone/Chorionic Somatomammotropin genes in pregnancies with pre-eclampsia and gestational diabetes mellitus. Mol Cell Endocrinol 2012; 355:180-7. [PMID: 22387044 PMCID: PMC3325480 DOI: 10.1016/j.mce.2012.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 02/09/2012] [Accepted: 02/09/2012] [Indexed: 12/23/2022]
Abstract
The human GH/CSH cluster consisting of one pituitary-expressed (GH1) and four placenta-expressed loci has been implicated in maternal metabolic adaptation to pregnancy, regulation of intrauterine and postnatal growth. We investigated how the mRNA expression profile of placental GH2, CSH1 and CSH2 genes and their alternative transcripts correlates with maternal pre-eclampsia (PE) and/or gestational diabetes mellitus (GD). The expression of studied genes in PE placentas (n=17) compared to controls (n=17) exhibited a trend for reduced transcript levels. The alternative transcripts retaining intron 4, GH2-2 and CSH1-2 showed significantly reduced expression in PE cases without growth restriction (P=0.007, P=0.008, respectively). In maternal GD (n=23), a tendency of differential expression was detected only for the GH2 gene and in pregnancies with large-for-gestational-age newborns. Our results, together with those reported by others, are consistent with a pleiotropic effect of placental hGH/CSH genes at the maternal-fetal interface relating to the regulation of fetal growth and the risk of affected maternal metabolism.
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Affiliation(s)
- Jaana Männik
- Human Molecular Genetics Group, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Pille Vaas
- Human Molecular Genetics Group, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
- Women’s Clinic of Tartu University Hospital, L. Puusepa 8, 51014 Tartu, Estonia
| | - Kristiina Rull
- Human Molecular Genetics Group, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
- Women’s Clinic of Tartu University Hospital, L. Puusepa 8, 51014 Tartu, Estonia
| | - Pille Teesalu
- Women’s Clinic of Tartu University Hospital, L. Puusepa 8, 51014 Tartu, Estonia
| | - Maris Laan
- Human Molecular Genetics Group, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
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Rugg-Gunn PJ. Epigenetic features of the mouse trophoblast. Reprod Biomed Online 2012; 25:21-30. [PMID: 22578826 DOI: 10.1016/j.rbmo.2012.01.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 11/13/2011] [Accepted: 01/04/2012] [Indexed: 01/21/2023]
Abstract
Trophoblast cells are required for the growth and survival of the fetus during pregnancy, and failure to maintain appropriate trophoblast regulation is associated with placental insufficiencies and intrauterine growth restriction. Development of the trophoblast lineage is mediated by interactions between genetic and epigenetic factors. This review will focus on new insights that have been gained from analysis of mouse models into the epigenetic mechanisms that are required for the early establishment of the trophoblast lineage and for the development of specialized cell types of the fetal placenta. In particular, the importance of DNA methylation, 5-hydroxymethylcytosine and histone modifications in orchestrating trophoblast gene expression and functional outcome will be discussed. These insights are beginning to be extended towards human studies and initial results suggest that the causes and consequences of a variety of placental pathologies are related to epigenetic processes. Furthermore, the epigenetic landscape that regulates trophoblast cells seems to be particularly vulnerable to perturbation during development. This has major implications for diet and other environmental factors during pregnancy.
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Affiliation(s)
- Peter J Rugg-Gunn
- Epigenetics Programme, The Babraham Institute, Babraham Research Campus, Cambridge, UK.
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21
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Bridging sequence diversity and tissue-specific expression by DNA methylation in genes of the mouse prolactin superfamily. Mamm Genome 2011; 23:336-45. [PMID: 22193412 DOI: 10.1007/s00335-011-9383-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 11/25/2011] [Indexed: 12/14/2022]
Abstract
Much of the DNA in genomes is organized within gene families and hierarchies of gene superfamilies. DNA methylation is the main epigenetic event involved in gene silencing and genome stability. In the present study, we analyzed the DNA methylation status of the prolactin (PRL) superfamily to obtain insight into its tissue-specific expression and the evolution of its sequence diversity. The PRL superfamily in mice consists of two dozen members, which are expressed in a tissue-specific manner. The genes in this family have CpG-less sequences, and they are located within a 1-Mb region as a gene cluster on chromosome 13. We tentatively grouped the family into several gene clusters, depending on location and gene orientation. We found that all the members had tissue-dependent differentially methylated regions (T-DMRs) around the transcription start site. The T-DMRs are hypermethylated in nonexpressing tissues and hypomethylated in expressing cells, supporting the idea that the expression of the PRL superfamily genes is subject to epigenetic regulation. Interestingly, the DNA methylation patterns of T-DMRs are shared within a cluster, while the patterns are different among the clusters. Finally, we reconstituted the nucleotide sequences of T-DMRs by converting TpG to CpG based on the consideration of a possible conversion of 5-methylcytosine to thymine by spontaneous deamination during the evolutionary process. On the phylogenic tree, the reconstituted sequences were well matched with the DNA methylation pattern of T-DMR and orientation. Our study suggests that DNA methylation is involved in tissue-specific expression and sequence diversity during evolution.
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22
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Krause B, Hanson M, Casanello P. Role of nitric oxide in placental vascular development and function. Placenta 2011; 32:797-805. [PMID: 21798594 PMCID: PMC3218217 DOI: 10.1016/j.placenta.2011.06.025] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 06/28/2011] [Accepted: 06/29/2011] [Indexed: 11/27/2022]
Abstract
Nitric oxide (NO) is one of the most pleiotropic signaling molecules at systemic and cellular levels, participating in vascular tone regulation, cellular respiration, proliferation, apoptosis and gene expression. Indeed NO actively participates in trophoblast invasion, placental development and represents the main vasodilator in this tissue. Despite the large number of studies addressing the role of NO in the placenta, its participation in placental vascular development and the effect of altered levels of NO on placental function remains to be clarified. This review draws a time-line of the participation of NO throughout placental vascular development, from the differentiation of vascular precursors to the consolidation of vascular function are considered. The influence of NO on cell types involved in the origin of the placental vasculature and the expression and function of the nitric oxide synthases (NOS) throughout pregnancy are described. The developmental processes involved in the placental vascular bed are considered, such as the participation of NO in placental vasculogenesis and angiogenesis through VEGF and Angiopoietin signaling molecules. The role of NO in vascular function once the placental vascular tree has developed, in normal pregnancy as well as in pregnancy-related diseases, is then discussed.
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Affiliation(s)
- B.J. Krause
- Division of Obstetrics and Gynecology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - M.A. Hanson
- Institute of Developmental Sciences, Academic Unit of Human Development & Health, Faculty of Medicine, University of Southampton, SO16 6YD, UK
| | - P. Casanello
- Division of Obstetrics and Gynecology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
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Lytras A, Detillieux K, Cattini PA. Identification of functional CCAAT/enhancer-binding protein and Ets protein binding sites in the human chorionic somatomammotropin enhancer sequences. J Mol Endocrinol 2011; 47:179-93. [PMID: 21737519 DOI: 10.1530/jme-11-0025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The human chorionic somatomammotropin (CS) A and B genes (listed as CSH1 and CSH2 in the HUGO database) are highly expressed in placenta. A 241 bp potent enhancer, nucleotides (nts) 1-241, located at the 3' end of the CS-B gene (CS-Benh) stimulates promoter activity specifically in placental trophoblast cells in vitro. Strong activity is exerted by a 23 bp element within the CS-Benh (nts 117-139), shown to interact with transcription enhancer factor (TEF) members of the transcription enhancer activator (TEA) DNA-binding domain-containing family. An identical TEF element is present in the homologous (97.5%) CS-Aenh; however, a few nucleotide differences suppress its activity. Previously, we identified regulatory sequences distinct from the TEF element within an 80 bp modulatory domain (nts 1-80) in the CS-Benh. Using structural and functional assays we now show that CCAAT/enhancer-binding protein (C/EBP) binding sites exist in the 80 bp modulatory domains of both enhancers, and an Elk-1 binding site exists in the modulatory domain of the CS-Aenh. C/EBPα or C/EBPβ strongly repressed CSp.CAT activity but stimulated CSp.CAT.CS-Benh activity. In contrast, the equivalent CS-A enhancer sequences were unable to relieve promoter repression. Elk-1 overexpression also resulted in differential effects on the CS-Aenh versus CS-Benh. Finally, we provide evidence for the association of C/EBPβ with the CS-A and CS-B genes in human placental chromatin, including differential involvement of C/EBPβ with the CS-Aenh versus the CS-Benh, and therefore consistent with the notion that these are regions of regulatory significance in vivo. We conclude that members of the C/EBP and Ets families can differentially modulate CS-Benh and CS-Aenh activity.
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Affiliation(s)
- Aristides Lytras
- Department of Physiology, University of Manitoba, Room 444, 745 Bannatyne Avenue, Winnipeg, Manitoba, Canada.
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24
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Jin Y, Oomah K, Cattini PA. Enhancer-blocking activity is associated with hypersensitive site V sequences in the human growth hormone locus control region. DNA Cell Biol 2011; 30:995-1005. [PMID: 21711161 DOI: 10.1089/dna.2011.1268] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Activation of the human growth hormone gene (hGH-N) is linked to a locus control region (LCR) containing four (I-III, V) hypersensitive sites (HS). Pit-1 binding to HS I/II is required for efficient pituitary expression. However, inclusion of HS III and V, located about 28 and 32 kb upstream of the hGH-N gene, respectively, is also required for consistent hGH-N expression levels in vivo. HS V is referred to as a boundary for the hGH LCR, but no specific enhancer blocking or barrier function is reported. We examined a 547 bp fragment containing HS V sequences (nucleotides -32,718/-32,172 relative to hGH-N) for enhancer-blocking activity using a well-established transient gene transfer system and assessed these sequences for CCCTC binding factor (CTCF), which is linked to enhancer-blocking activity. The 547 bp HS V fragment decreased enhancer activity with a reverse-orientation preference when inserted between HS III enhancer sequences and a minimal thymidine kinase promoter (TKp). These sequences are associated with CTCF in human pituitary and nonpituitary chromatin. Enhancer-blocking activity with an orientation preference was further localized to a 45 bp sub-fragment, with evidence of CTCF and upstream binding factor 1 (USF1) binding; USF1 is linked more closely with barrier function. The presence of yin and yang 1 (Yy1) that cooperates with CTCF in the regulation of X-chromosome inactivation was also seen. A decrease in CTCF and Yy1 RNA levels was associated with a significant reduction in enhancer-blocking activity. Assessment of CpG-dinucleotides in the TKp indicates that the presence of HS V sequences are associated with an increased incidence of CpG-dinucleotide methylation of the GC box region. These data support association of CTCF and enhancer-blocking activity with HS V that is consistent with a role as a (LCR) boundary element and also implicates Yy1 in this process.
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Affiliation(s)
- Yan Jin
- Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada
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Idelman G, Jacobson EM, Tuttle TR, Ben-Jonathan N. Lactogens and estrogens in breast cancer chemoresistance. Expert Rev Endocrinol Metab 2011; 6:411-422. [PMID: 21731573 PMCID: PMC3125604 DOI: 10.1586/eem.11.19] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tumor resistance to chemotherapy in advanced breast cancer is a major impediment to treatment success. Resistance can be induced by the drugs themselves or result from the action of internal factors. The role of hormones in chemoresistance has received little attention. This article focuses on two classes of hormones: lactogens and estrogens. Lactogens include prolactin, growth hormone and placental lactogen, all of which can activate the prolactin receptor. Estrogens include endogenous steroids and nonsteroidal compounds from the environment termed endocrine disruptors, all of which can activate 'classical' estrogen receptors (ERα and ERβ), as well as other types of receptors. Both lactogens and estrogens antagonize cytotoxicity of multiple chemotherapeutic agents through complementary mechanisms. The implications of chemoresistance by these hormones to patients with breast cancer, and the potential benefits of developing combinatorial anti-lactogen/anti-estrogen treatment regimens, are discussed.
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Affiliation(s)
- Gila Idelman
- Department of Cancer and Cell Biology, University of Cincinnati, 7315 Eden Avenue, Cincinnati, OH 45267-0521, USA
| | - Eric M Jacobson
- Department of Cancer and Cell Biology, University of Cincinnati, 7315 Eden Avenue, Cincinnati, OH 45267-0521, USA
| | - Traci R Tuttle
- Department of Cancer and Cell Biology, University of Cincinnati, 7315 Eden Avenue, Cincinnati, OH 45267-0521, USA
| | - Nira Ben-Jonathan
- Department of Cancer and Cell Biology, University of Cincinnati, 7315 Eden Avenue, Cincinnati, OH 45267-0521, USA
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Sizova D, Ho Y, Cooke NE, Liebhaber SA. Research resource: T-antigen transformation of pituitary cells captures three novel cell lines in the Pit-1 lineage. Mol Endocrinol 2010; 24:2232-40. [PMID: 20829390 DOI: 10.1210/me.2010-0235] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We report the establishment of three distinct pituitary-derived murine cell lines generated by targeted T-antigen-induced transformation. The Pit1/0 line expresses pituitary-specific transcription factor-1 (Pit-1) but lacks expression of GH, prolactin (Prl), or TSH, and the Pit1/Prl line is selectively positive for Pit-1 and Prl. The third line, Pit1/Triple, expresses Pit-1 and all three of the Pit-1-dependent hormones: GH, Prl, and TSHβ/glycoprotein hormone α-subunit. The three corresponding transformation events appear to have captured pituitary cells representing: 1) an initial step in the Pit-1(+) lineage, 2) a cell line that corresponds to the differentiated lactotrope, and 3) a novel tri-hormone intermediate that may represent a pivotal step in Pit-1(+) cell lineage differentiation. The documented dependence of the tri-hormone expression in the Pit-1/Triple line on Pit-1 activity supports its potential role in the pathway of pituitary cell differentiation. The presence of a 123-kb human transgene encompassing the hGH locus (hGH/bacterial artificial chromosome) in two of these lines, Pit1/0 and Pit1/Prl, further expands their potential utility to the analysis of gene activation within the hGH gene cluster.
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Affiliation(s)
- Daria Sizova
- Room 560A Clinical Research Building, 415 Curie Boulevard, Philadelphia, Pennsylvania 19104, USA
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Yang X, Jin Y, Cattini PA. Appearance of the pituitary factor Pit-1 increases chromatin remodeling at hypersensitive site III in the human GH locus. J Mol Endocrinol 2010; 45:19-32. [PMID: 20395397 PMCID: PMC5156566 DOI: 10.1677/jme-10-0017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Expression of pituitary and placental members of the human GH and chorionic somatomammotropin (CS) gene family is directed by an upstream remote locus control region (LCR). Pituitary-specific expression of GH requires direct binding of Pit-1 (listed as POU1F1 in the HUGO database) to sequences marked by a hypersensitive site (HS) region (HS I/II) 14.6 kb upstream of the GH-N gene (listed as GH1 in the HUGO database). We used human embryonic kidney 293 (HEK293) cells overexpressing wild-type and mutant Pit-1 proteins as a model system to gain insight into the mechanism by which Pit-1 gains access to the GH LCR. Addition of Pit-1 to these cells increased DNA accessibility at HS III, located 28 kb upstream of the human GH-N gene, in a POU homeodomain-dependent manner, as reflected by effects on histone hyperacetylation and RNA polymerase II activity. Direct binding of Pit-1 to HS III sequences is not supported. However, the potential for binding of ETS family members to this region has been demonstrated, and Pit-1 association with this ETS element in HS III sequences requires the POU homeodomain. Also, both ETS1 and ELK1 co-precipitate from human pituitary extracts using two independent sources of Pit-1 antibodies. Finally, overexpression of ELK1 or Pit-1 expression in HEK293 cells increased GH-N RNA levels. However, while ELK1 overexpression also stimulated placental CS RNA levels, the effect of Pit-1 appeared to correlate with ETS factor levels and target GH-N preferentially. These data are consistent with recruitment and an early role for Pit-1 in remodeling of the GH LCR at the constitutively open HS III through protein-protein interaction.
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Affiliation(s)
- Xiaoyang Yang
- Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada
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Matsubara S, Takahashi T, Kimura AP. Epigenetic patterns at the mouse prolyl oligopeptidase gene locus suggest the CpG island in the gene body to be a novel regulator for gene expression. Gene 2010; 465:17-29. [PMID: 20600704 DOI: 10.1016/j.gene.2010.06.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 06/16/2010] [Accepted: 06/17/2010] [Indexed: 10/19/2022]
Abstract
Prolyl oligopeptidase (POP) is a widely distributed serine peptidase which hydrolyzes small peptides on the carboxyl side of an internal proline residue. While its physiological role has been intensely studied, the regulatory mechanism of the gene expression is poorly understood. This time we assessed the POP mRNA expression in mouse embryos and tissues related to reproduction and development and found that POP mRNA was highly expressed in the ovarian granulosa cell, placental spongiotrophoblast, and blastocyst embryo. To elucidate the mechanism by which POP expression is regulated, we investigated DNA methylation and histone modification patterns of the two CpG islands (CGIs) found at the mouse POP locus. Whereas the CGI including the POP promoter (CGI-1) was completely hypomethylated in all the tissues examined, DNA methylation level of the CGI in the gene body (CGI-2) was lower in the granulosa cell, placenta, and blastocyst than in the liver. Some specific CpGs in CGI-2 were significantly demethylated in the three tissues. An in vitro reporter analysis indicated that CGI-2 enhanced POP promoter activity and its effect was significantly reduced by DNA methylation. Moreover, histone H3 acetylation and H3K4 methylation levels of CGI-2 were higher in the granulosa cell than liver. The results suggest that the CGI-2 region is a cis-element for the POP gene expression.
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Affiliation(s)
- Shin Matsubara
- Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
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Männik J, Vaas P, Rull K, Teesalu P, Rebane T, Laan M. Differential expression profile of growth hormone/chorionic somatomammotropin genes in placenta of small- and large-for-gestational-age newborns. J Clin Endocrinol Metab 2010; 95:2433-42. [PMID: 20233782 PMCID: PMC2869554 DOI: 10.1210/jc.2010-0023] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 02/18/2010] [Indexed: 11/19/2022]
Abstract
CONTEXT The human growth hormone/chorionic somatomammotropin (hGH/CSH) locus at 17q22-24, consisting of one pituitary-expressed postnatal (GH1) and four placenta-expressed genes (GH2, CSH1, CSH2, and CSHL1), is implicated in regulation of postnatal and intrauterine growth. A positive correlation has been reported between the offspring's birth weight and serum placental GH (coded by GH2) and placental lactogen (coded by CSH1, CSH2) levels in pregnant women. OBJECTIVE The objective of the study was the investigation of the hypothesis that the mRNA expression profile of placental hGH/CSH genes contributes to the determination of birth weight. DESIGN AND SUBJECTS We developed a sensitive, fluorescent-labeled semiquantitative RT-PCR assay coupled with gene-specific restriction analysis, capable of distinguishing alternative splice-products of individual placental hGH/CSH genes and quantification of their relative expression levels. The detailed profile of alternative transcripts of GH2, CSH1, CSH2, and CSHL1 genes in placenta from uncomplicated term pregnancies of the REPROMETA sample collection was addressed in association with the birth weight of newborns, grouped as appropriate for gestational age (AGA; n = 23), small for gestational age (SGA; n = 15), and large for gestational age (LGA; n = 34). RESULTS The majority of pregnancies with SGA newborn showed down-regulation of the entire hGH/CSH cluster in placenta, whereas in the case of LGA, the expression of CSH1-1, CSH2-1, and CSHL1-4 mRNA transcripts in placenta was significantly increased compared with AGA newborns (P < 0.0001, P = 0.009, P = 0.002, respectively). CONCLUSION The expression profile of placental hGH/CSH genes in placenta is altered in pregnancies accompanied by SGA and LGA compared with AGA newborns, and thus, it may directly affect the circulating fetal and maternal placental GH and placental lactogen levels.
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Affiliation(s)
- Jaana Männik
- Institute of Molecular and Cell Biology, University of Tartu, Riia Street 23, 51010 Tartu, Estonia.
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Kumar P, Kamat A, Mendelson CR. Estrogen receptor alpha (ERalpha) mediates stimulatory effects of estrogen on aromatase (CYP19) gene expression in human placenta. Mol Endocrinol 2009; 23:784-93. [PMID: 19299445 DOI: 10.1210/me.2008-0371] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A 246-bp region upstream of placenta-specific exon I.1 of the human aromatase (hCYP19) gene mediates placenta-specific, developmental, and O(2) regulation of expression. In this study, trophoblast differentiation and associated induction of CYP19 expression were prevented when cytotrophoblasts were cultured in phenol red-free medium containing charcoal-stripped serum or with the estrogen receptor (ER) antagonist, ICI 182,780, suggesting a stimulatory role of estrogen/ER. ERalpha protein was expressed in human trophoblasts and increased during syncytiotrophoblast differentiation, whereas ERbeta was undetectable. Mutational analysis revealed that an estrogen response element-like sequence (ERE-LS) at -208 bp is required for inductive effects of estradiol/ERalpha on hCYP19I.1 promoter activity in transfected COS-7 cells. Increased binding of syncytiotrophoblast compared with cytotrophoblast nuclear proteins to the ERE-LS was observed in vitro; however, ERalpha antibodies failed to supershift the complex and in vitro-transcribed/translated ERalpha did not bind. Nonetheless, chromatin immunoprecipitation assays in cultured trophoblasts revealed recruitment of endogenous ERalpha to the -255- to -155-bp region containing the ERE-LS before induction of hCYP19 expression; this was inhibited by ICI 182,780. Chromatin immunoprecipitation also revealed increased acetylated histone H3(K9/14) and decreased methylated histone H3(K9) associated with this region during trophoblast differentiation. These modifications were prevented when trophoblasts were incubated with ICI 182,780, suggesting that ERalpha recruitment to the -255- to -155-bp region promotes histone modifications leading to increased hCYP19 transcription. Thus, during trophoblast differentiation, estrogen/ERalpha exerts a positive feedback role, which promotes permissive histone modifications that are associated with induction of hCYP19 gene transcription.
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Affiliation(s)
- Premlata Kumar
- Department of Biochemistry, The University of Texas Southwestern Medical Center at Dallas, 75390-9038, USA
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Ellery PM, Cindrova-Davies T, Jauniaux E, Ferguson-Smith AC, Burton GJ. Evidence for transcriptional activity in the syncytiotrophoblast of the human placenta. Placenta 2009; 30:329-34. [PMID: 19215981 PMCID: PMC3712185 DOI: 10.1016/j.placenta.2009.01.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 01/08/2009] [Accepted: 01/09/2009] [Indexed: 11/24/2022]
Abstract
The aim was to test for evidence of transcriptional activity within the nuclei of the syncytiotrophoblast of the human placenta. The syncytiotrophoblast forms the epithelial covering of the villous tree, and is a multinucleated, terminally-differentiated syncytium generated through fusion of the underlying progenitor cytotrophoblast cells. Its nuclei are heterogeneous with respect to chromatin condensation, and previous functional studies of 3H-uridine uptake in vitro have indicated that they are transcriptionally inactive. This observation is surprising given the key roles this tissue plays in active transport, hormone synthesis and metabolic regulation, and has widespread implications for trophoblast physiology and pathophysiology. We used three different approaches to look for evidence of transcriptional activity. First, immunofluorescence staining was performed on paraffin-embedded early pregnancy and term placental villi, using an antibody directed specifically against the actively transcribing form of RNA polymerase II. Second, a nucleoside incorporation assay was applied to placental villi maintained in short-term culture, with and without the transcription blocker α-amanitin. Third, histone modifications associated with active chromatin were identified by immunohistochemistry and immunofluorescence. Each of these methods showed transcription to be occurring in a proportion of syncytiotrophoblast nuclei, with qualitative evidence for transcription being more abundant in the first trimester than at term. These findings correlated with electron microscopical observations of prominent nucleoli within the nuclei, particularly during early pregnancy, signifying transcription of ribosomal RNA. Contrary to previous findings, these results confirm that a proportion of syncytiotrophoblast nuclei actively produce mRNA transcripts.
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Affiliation(s)
- P M Ellery
- Centre for Trophoblast Research, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
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Jin Y, Lu SY, Fresnoza A, Detillieux KA, Duckworth ML, Cattini PA. Differential placental hormone gene expression during pregnancy in a transgenic mouse containing the human growth hormone/chorionic somatomammotropin locus. Placenta 2009; 30:226-35. [PMID: 19168217 DOI: 10.1016/j.placenta.2008.12.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 12/16/2008] [Accepted: 12/18/2008] [Indexed: 01/01/2023]
Abstract
The human (h) growth hormone/chorionic somatomammotropin (GH/CS) gene locus presents a unique model to gain insight into the molecular mechanisms that have allowed a closely related family of genes to be expressed in two distinct cell lineages/tissues: pituitary somatotrophs and placental syncytiotrophoblasts. However, studies of external factors that regulate gene expression have been somewhat limited by (i) a lack of human cell lines expressing endogenous GH or CS appropriately; and (ii) the fact that the GH/CS locus is unique to primates and thus does not exist in rodents. In the current study, a transgenic (171 h GH/CS-TG) mouse was generated containing the intact hGH/CS gene cluster and hGH locus control region (LCR) in a 171-kilobase DNA fragment. Pituitary and placental-specific expression of hGH/CS RNA was detected at embryonic day (E) 18.5. Immunostaining of hGH was seen in somatotrophs of the anterior pituitary beginning in late gestation. The presence of hCS protein was detected in the placental labyrinth in trophoblasts functionally analogous to the syncytiotrophoblast of the chorionic villi. This pattern of gene expression is consistent with the presence of essential components of the hGH/CS LCR. Transcript levels for hCS-A, hCS-B and placental hGH-variant increased in 171 hGH/CS-TG placenta during gestation (E11.5-E18.5), as previously observed in human placental development. Throughout gestation, hCS-A RNA levels were proportionately higher, accounting for 91% of total CS RNA by E18.5, comparable to term human placenta. Finally, the previous correlation between the transcription factor AP-2alpha and hCS RNA expression observed in developing primary human cytotrophoblast cultures, was extended to pregnancy in the 171 hGH/CS-TG mouse. The 171 hGH/CS-TG mouse thus provides a model to investigate hGH/CS gene expression, including in pregnancy.
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Affiliation(s)
- Y Jin
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB, Canada R3E 0J9
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