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Brinkmeier ML, Bando H, Camarano AC, Fujio S, Yoshimoto K, de Souza FS, Camper SA. Rathke's cleft-like cysts arise from Isl1 deletion in murine pituitary progenitors. J Clin Invest 2021; 130:4501-4515. [PMID: 32453714 DOI: 10.1172/jci136745] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/14/2020] [Indexed: 12/15/2022] Open
Abstract
The transcription factor ISL1 is expressed in pituitary gland stem cells and the thyrotrope and gonadotrope lineages. Pituitary-specific Isl1 deletion causes hypopituitarism with increased stem cell apoptosis, reduced differentiation of thyrotropes and gonadotropes, and reduced body size. Conditional Isl1 deletion causes development of multiple Rathke's cleft-like cysts, with 100% penetrance. Foxa1 and Foxj1 are abnormally expressed in the pituitary gland and associated with a ciliogenic gene-expression program in the cysts. We confirmed expression of FOXA1, FOXJ1, and stem cell markers in human Rathke's cleft cyst tissue, but not craniopharyngiomas, which suggests these transcription factors are useful, pathological markers for diagnosis of Rathke's cleft cysts. These studies support a model whereby expression of ISL1 in pituitary progenitors drives differentiation into thyrotropes and gonadotropes and without it, activation of FOXA1 and FOXJ1 permits development of an oral epithelial cell fate with mucinous cysts. This pituitary-specific Isl1 mouse knockout sheds light on the etiology of Rathke's cleft cysts and the role of ISL1 in normal pituitary development.
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Affiliation(s)
- Michelle L Brinkmeier
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Hironori Bando
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Adriana C Camarano
- Institute of Physiology, Molecular Biology, and Neurosciences-IFIBYNE-CONICET, Pabellon IFIBYNE, Ciudad Universitaria, Buenos Aires, Argentina
| | - Shingo Fujio
- Graduate School of Medical and Dental Sciences, Department of Neurosurgery, Kagoshima University, Kagoshima, Japan
| | - Koji Yoshimoto
- Graduate School of Medical and Dental Sciences, Department of Neurosurgery, Kagoshima University, Kagoshima, Japan
| | - Flávio Sj de Souza
- Institute of Physiology, Molecular Biology, and Neurosciences-IFIBYNE-CONICET, Pabellon IFIBYNE, Ciudad Universitaria, Buenos Aires, Argentina
| | - Sally A Camper
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
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2
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Cattini PA, Jin Y, Jarmasz JS, Noorjahan N, Bock ME. Obesity and regulation of human placental lactogen production in pregnancy. J Neuroendocrinol 2020; 32:e12859. [PMID: 32500948 DOI: 10.1111/jne.12859] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/19/2020] [Accepted: 04/21/2020] [Indexed: 12/16/2022]
Abstract
The four genes coding for placental members of the human (h) growth hormone (GH) family include two that code independently for placental lactogen (PL), also known as chorionic somatomammotrophin hormone, one that codes for placental growth hormone (PGH) and a pseudogene for which RNA but no protein product is reported. These genes are expressed preferentially in the villus syncytiotrophoblast of the placenta in pregnancy. In higher primates, the placental members, including hPL and PGH, are the result of multiple duplication events of the GH gene. This contrasts with rodents and ruminants, where PLs result from duplication of the prolactin (PRL) gene. Thus, unlike their mouse counterparts, the hPL and PGH hormones bind both lactogenic and somatogenic receptors with varying affinity. Roles influenced by nutrient availability in both metabolic control in pregnancy and maternal behaviour are supported. However, the effect maternal obesity has on the activation of placental members of the hGH gene family, particularly the expression and function of those genes, is poorly understood. Evidence from partially humanised hGH/PL transgenic mice indicates that both the remote upstream hPL locus control region (LCR) and more gene-related regulatory regions are required for placental expression in vivo. Furthermore, a specific pattern of interactions between the LCR and hPL gene promoter regions is detected in term placenta chromatin from women with a normal body mass index (BMI) in the range 18.5-25 kg m-2 by chromosome conformation capture assay. This pattern is disrupted with maternal obesity (class II BMI > 35 kg m-2 ) and associated with a > 40% decrease in term hPL RNA levels, as well as serum hPL but not PRL levels, during pregnancy. The relative importance of the chromosomal architecture and predicted properties for transcription factor participation in terms of hPL production and response to obesity are considered, based on comparison with components required for efficient human pituitary GH gene expression.
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Affiliation(s)
- Peter A Cattini
- Department of Physiology & Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - Yan Jin
- Department of Physiology & Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - Jessica S Jarmasz
- Department of Physiology & Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - Noshin Noorjahan
- Department of Physiology & Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
| | - Margaret E Bock
- Department of Physiology & Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
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3
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Fortunati N, Guaraldi F, Zunino V, Penner F, D'Angelo V, Zenga F, Pecori Giraldi F, Catalano MG, Arvat E. Effects of environmental pollutants on signaling pathways in rat pituitary GH3 adenoma cells. ENVIRONMENTAL RESEARCH 2017; 158:660-668. [PMID: 28732322 DOI: 10.1016/j.envres.2017.07.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 05/26/2017] [Accepted: 07/06/2017] [Indexed: 06/07/2023]
Abstract
An increased rate of acromegaly was reported in industrialized areas, suggesting an involvement of environmental pollutants in the pathogenesis and behavior of GH-secreting pituitary adenomas. Based on these premises, the aim of the study was to evaluate the effects of some widely diffused pollutants (i.e. benzene, BZ; bis(2-ethylhexyl) phthalate, DEHP and polychlorinated biphenyls, PCB) on growth hormone secretion, the somatostatin and estrogenic pathways, viability and proliferation of rat GH-producing pituitary adenoma (GH3) cells. All the pollutants induced a statistically significant increase in GH secretion and interfered with cell signaling. They all modulated the expression of SSTR2 and ZAC1, involved in the somatostatin signaling, and the expression of the transcription factor FOXA1, involved in the estrogen receptor signaling. Moreover, all the pollutants increased the expression of the CYP1A1, suggesting AHR pathway activation. None of the pollutants impacted on cell proliferation or viability. Present data demonstrate that exposure to different pollutants, used at in vivo relevant concentrations, plays an important role in the behavior of GH3 pituitary adenoma cells, by increasing GH secretion and modulating several cellular signaling pathways. These observations support a possible influence of different pollutants in vivo on the GH-adenoma aggressiveness and biological behavior.
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Affiliation(s)
- Nicoletta Fortunati
- Division of Oncological Endocrinology, Città della Salute e della Scienza University Hospital, I-10126 Turin, Italy
| | - Federica Guaraldi
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Sciences, Città della Salute e della Scienza University Hospital, I-10126 Turin, Italy
| | - Valentina Zunino
- Division of Oncological Endocrinology, Città della Salute e della Scienza University Hospital, I-10126 Turin, Italy
| | - Federica Penner
- Division of Neurosurgery, Città della Salute e della Scienza University Hospital, I-10126 Turin, Italy
| | - Valentina D'Angelo
- Division of Oncological Endocrinology, Città della Salute e della Scienza University Hospital, I-10126 Turin, Italy
| | - Francesco Zenga
- Division of Neurosurgery, Città della Salute e della Scienza University Hospital, I-10126 Turin, Italy
| | - Francesca Pecori Giraldi
- Neuroendocrinology Research Laboratory, Istituto Auxologico Italiano IRCCS, Cusano Milanino, (MI), Italy and Department of Clinical Sciences and Community Health, University of Milan, I-20149 Milan, Italy
| | | | - Emanuela Arvat
- Division of Oncological Endocrinology, Città della Salute e della Scienza University Hospital, I-10126 Turin, Italy; Department of Medical Sciences, University of Turin, I-10126 Turin, Italy.
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4
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Pérez-Maya AA, Wallis M, Barrera-Saldaña HA. Structure and evolution of the gorilla and orangutan growth hormone loci. Mamm Genome 2016; 27:511-23. [DOI: 10.1007/s00335-016-9654-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/15/2016] [Indexed: 11/30/2022]
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5
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Vakili H, Jin Y, Cattini PA. Evidence for a Circadian Effect on the Reduction of Human Growth Hormone Gene Expression in Response to Excess Caloric Intake. J Biol Chem 2016; 291:13823-33. [PMID: 27151213 PMCID: PMC4919464 DOI: 10.1074/jbc.m116.722744] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/02/2016] [Indexed: 11/06/2022] Open
Abstract
Rhythmicity of biological functions is fundamental for optimal adaptations to environmental cues. Growth hormone (GH) is a major metabolic homeostatic factor that is secreted with a circadian pattern, but whether it is synthesized rhythmically is unknown. We used transgenic mice containing the human (h) GH gene (hGH1) locus to investigate the rhythmicity of hGH synthesis and secretion and to show that RNA and secreted protein levels oscillate over a 24-h cycle. Analysis of hGH1 promoter sequences revealed an enhancer motif (E-box) element that binds the circadian transcriptional machinery (Bmal1 and Clock). Furthermore, Bmal1/Clock were able to transactivate the hGH1 promoter, and mutation of this E-box element adversely affected basal activity after gene transfer. The ability of Bmal1 to bind the hGH1 promoter region containing the E-box element was confirmed in the hGH1 transgenic mouse pituitary in situ Occupancy was reduced in mice fed a high fat diet during the light (inactive) stage of the daily cycle in mice and corresponded to a decrease in hGH1 RNA levels. The decreases in occupancy and RNA levels were not seen, however, during the dark (active) stage. A chromatin loop required for efficient postnatal hGH1 expression was negatively affected by the high fat diet in the light but not dark stage similar to the pattern observed with Bmal1 association with the promoter region. This is the first evidence that hGH synthesis follows a diurnal rhythm and of dynamic associations of the circadian machinery with a component of a chromosomal structure of the hGH1 locus that is essential for efficient expression.
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Affiliation(s)
- Hana Vakili
- From the Departments of Internal Medicine and
| | - Yan Jin
- Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Peter A Cattini
- Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
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6
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Loss of Foxm1 Results in Reduced Somatotrope Cell Number during Mouse Embryogenesis. PLoS One 2015; 10:e0128942. [PMID: 26075743 PMCID: PMC4468165 DOI: 10.1371/journal.pone.0128942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 05/01/2015] [Indexed: 12/31/2022] Open
Abstract
FOXM1, a member of the forkhead box transcription factor family, plays a key role in cell cycling progression by regulating the expression of critical G1/S and G2/M phase transition genes. In vivo studies reveal that Foxm1 null mice have a 91% lethality rate at e18.5 due to significant cardiovascular and hepatic hypoplasia. Thus, FOXM1 has emerged as a key protein regulating mitotic division and cell proliferation necessary for embryogenesis. In the current study, we assess the requirement for Foxm1 in the developing pituitary gland. We find that Foxm1 is expressed in the pituitary at embryonic days 10.5-e18.5 and localizes with markers for active cell proliferation (BrdU). Interestingly, direct analysis of Foxm1 null mice at various embryonic ages, reveals no difference in gross pituitary morphology or cell proliferation. We do observe a downward trend in overall pituitary cell number and a small reduction in pituitary size in e18.5 embryos suggesting there may be subtle changes in pituitary proliferation not detected with our proliferation makers. Consistent with this, Foxm1 null mice have reductions in both the somatotrope and gonadotrope cell populations.
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7
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Grabowska MM, Elliott AD, DeGraff DJ, Anderson PD, Anumanthan G, Yamashita H, Sun Q, Friedman DB, Hachey DL, Yu X, Sheehan JH, Ahn JM, Raj GV, Piston DW, Gronostajski RM, Matusik RJ. NFI transcription factors interact with FOXA1 to regulate prostate-specific gene expression. Mol Endocrinol 2014; 28:949-64. [PMID: 24801505 DOI: 10.1210/me.2013-1213] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Androgen receptor (AR) action throughout prostate development and in maintenance of the prostatic epithelium is partly controlled by interactions between AR and forkhead box (FOX) transcription factors, particularly FOXA1. We sought to identity additional FOXA1 binding partners that may mediate prostate-specific gene expression. Here we identify the nuclear factor I (NFI) family of transcription factors as novel FOXA1 binding proteins. All four family members (NFIA, NFIB, NFIC, and NFIX) can interact with FOXA1, and knockdown studies in androgen-dependent LNCaP cells determined that modulating expression of NFI family members results in changes in AR target gene expression. This effect is probably mediated by binding of NFI family members to AR target gene promoters, because chromatin immunoprecipitation (ChIP) studies found that NFIB bound to the prostate-specific antigen enhancer. Förster resonance energy transfer studies revealed that FOXA1 is capable of bringing AR and NFIX into proximity, indicating that FOXA1 facilitates the AR and NFI interaction by bridging the complex. To determine the extent to which NFI family members regulate AR/FOXA1 target genes, motif analysis of publicly available data for ChIP followed by sequencing was undertaken. This analysis revealed that 34.4% of peaks bound by AR and FOXA1 contain NFI binding sites. Validation of 8 of these peaks by ChIP revealed that NFI family members can bind 6 of these predicted genomic elements, and 4 of the 8 associated genes undergo gene expression changes as a result of individual NFI knockdown. These observations suggest that NFI regulation of FOXA1/AR action is a frequent event, with individual family members playing distinct roles in AR target gene expression.
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Affiliation(s)
- Magdalena M Grabowska
- Department of Urologic Surgery (M.M.G., G.A. H.Y., Q.S., X.Y., R.J.M.), Department of Molecular Physiology and Biophysics (A.D.E., D.W.P.), and Vanderbilt-Ingram Cancer Center (R.J.M.), Vanderbilt University Medical Center, Nashville, Tennessee 37232; Department of Pathology (D.J.D.), Penn State University College of Medicine, Hershey, Pennsylvania 17033; Department of Biological Sciences (P.D.A.), Salisbury University, Salisbury, Maryland 21801; Mass Spectrometry Research Center (D.B.F., D.L.H.), Department of Biochemistry, Department of Biochemistry and Center for Structural Biology (J.H.S.), and Department of Cell and Developmental Biology (R.J.M.), Vanderbilt University, Nashville, Tennessee 37232; Department of Chemistry (J.-M.A.), University of Texas Dallas, Dallas, Texas 75080; Department of Urology (G.V.R.), University of Texas Southwestern, Dallas, Texas 75390; and Department of Biochemistry (R.M.G.), Developmental Genomics Group, NY State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, New York 14203
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8
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Thackray VG. Fox tales: regulation of gonadotropin gene expression by forkhead transcription factors. Mol Cell Endocrinol 2014; 385:62-70. [PMID: 24099863 PMCID: PMC3947687 DOI: 10.1016/j.mce.2013.09.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 09/25/2013] [Accepted: 09/26/2013] [Indexed: 12/16/2022]
Abstract
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are produced by pituitary gonadotrope cells and are required for steroidogenesis, the maturation of ovarian follicles, ovulation, and spermatogenesis. Synthesis of LH and FSH is tightly regulated by a complex network of signaling pathways activated by hormones including gonadotropin-releasing hormone, activin and sex steroids. Members of the forkhead box (FOX) transcription factor family have been shown to act as important regulators of development, homeostasis and reproduction. In this review, we focus on the role of four specific FOX factors (FOXD1, FOXL2, FOXO1 and FOXP3) in gonadotropin hormone production and discuss our current understanding of the molecular function of these factors derived from studies in mouse genetic and cell culture models.
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Affiliation(s)
- Varykina G Thackray
- Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
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9
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The forkhead transcription factor, Foxd1, is necessary for pituitary luteinizing hormone expression in mice. PLoS One 2012; 7:e52156. [PMID: 23284914 PMCID: PMC3526578 DOI: 10.1371/journal.pone.0052156] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 11/15/2012] [Indexed: 12/05/2022] Open
Abstract
The pituitary gland regulates numerous physiological functions including growth, reproduction, temperature and metabolic homeostasis, lactation, and response to stress. Pituitary organogenesis is dependent on signaling factors that are produced in and around the developing pituitary. The studies described in this report reveal that the forkhead transcription factor, Foxd1, is not expressed in the developing mouse pituitary gland, but rather in the mesenchyme surrounding the pituitary gland, which is an essential source of signaling factors that regulate pituitary organogenesis. Loss of Foxd1 causes a morphological defect in which the anterior lobe of the pituitary gland protrudes through the cartilage plate that is developing ventral to the pituitary at embryonic days (e)14.5, e16.5, and e18.5. The number of proliferating pituitary cells is increased at e14.5 and e16.5. Loss of Foxd1 also results in significantly decreased levels of Lhb expression at e18.5. This decrease in Lhb expression does not appear to be due to a change in the number of gonadotrope cells in the pituitary gland. Previous studies have shown that loss of the LIM homeodomain factor, Lhx3, which is activated by the FGF signaling pathway, results in loss of LH production. Although there is a difference in Lhb expression in Foxd1 null mice, the expression pattern of LHX3 is not altered in Foxd1 null mice. These studies suggest that Foxd1 is indirectly required for normal Lhb expression and cartilage formation.
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10
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Vakili H, Jin Y, Cattini PA. Negative regulation of human growth hormone gene expression by insulin is dependent on hypoxia-inducible factor binding in primary non-tumor pituitary cells. J Biol Chem 2012; 287:33282-92. [PMID: 22833680 DOI: 10.1074/jbc.m112.380949] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Insulin controls growth hormone (GH) production at multiple levels, including via a direct effect on pituitary somatotrophs. There are no data, however, on the regulation of the intact human (h) GH gene (hGH1) by insulin in non-tumor pituitary cells, but the proximal promoter region (nucleotides -496/+1) responds negatively to insulin in transfected pituitary tumor cells. A DNA-protein interaction was also induced by insulin at nucleotides -308/-235. Here, we confirmed the presence of a hypoxia-inducible factor 1 (HIF-1) binding site within these sequences (-264/-259) and investigated whether HIF-1 is associated with insulin regulation of "endogenous" hGH1. In the absence of primary human pituitary cells, transgenic mice expressing the intact hGH locus in a somatotroph-specific manner were generated. A significant and dose-dependent decrease in hGH and mouse GH RNA levels was detected in primary pituitary cell cultures from these mice with insulin treatment. Increasing HIF-1α availability with a hypoxia mimetic significantly decreased hGH RNA levels and was accompanied by recruitment of HIF-1α to the hGH1 promoter in situ as seen with insulin. Both inhibition of HIF-1 DNA binding by echinomycin and RNA interference of HIF-1α synthesis blunted the negative effect of insulin on hGH1 but not mGH. The insulin response is also sensitive to histone deacetylase inhibition/trichostatin A and associated with a decrease in H3/H4 hyperacetylation in the proximal hGH1 promoter region. These data are consistent with HIF-1-dependent down-regulation of hGH1 by insulin via chromatin remodeling specifically in the proximal promoter region.
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Affiliation(s)
- Hana Vakili
- Department of Physiology, Division of Endocrine and Metabolic diseases, University of Manitoba, Winnipeg, Manitoba, Canada
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11
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Pérez-Maya AA, Rodríguez-Sánchez IP, de Jong P, Wallis M, Barrera-Saldaña HA. The chimpanzee GH locus: composition, organization, and evolution. Mamm Genome 2012; 23:387-98. [DOI: 10.1007/s00335-012-9392-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Accepted: 12/31/2011] [Indexed: 12/27/2022]
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12
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Vakili H, Jin Y, Nagy JI, Cattini PA. Transgenic mice expressing the human growth hormone gene provide a model system to study human growth hormone synthesis and secretion in non-tumor-derived pituitary cells: differential effects of dexamethasone and thyroid hormone. Mol Cell Endocrinol 2011; 345:48-57. [PMID: 21777655 DOI: 10.1016/j.mce.2011.07.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/14/2011] [Accepted: 07/05/2011] [Indexed: 11/17/2022]
Abstract
Growth hormone (GH) is regulated by pituitary and hypothalamic factors as well as peripheral endocrine factors including glucocorticoids and thyroid hormone. Studies on human GH are limited largely to the assessment of plasma levels in endocrine disorders. Thus, insight into the regulation of synthesis versus secretion has come mainly from studies done on non-human GH and/or pituitary tumor cells. However, primate and non-primate GH gene loci have differences in their structure and, by extension, regulation. We generated transgenic (171hGH/CS-TG) mice containing the intact hGH1 gene and locus control region, including sequences required for integration-independent and preferential pituitary expression. Here, we show hGH co-localizes with mouse (m) GH in somatotrophs in situ and in primary pituitary cells. Dexamethasone treatment increased hGH and mGH, as well as GH releasing hormone (GHRH) receptor RNA levels, and hGH release was stimulated by GHRH treatment. By contrast, triiodothyronine decreased or had no effect on hGH and mGH production, respectively, and the negative effect on hGH was also seen in the presence of dexamethasone. Thus, 171hGH/CS-TG mouse pituitary cultures represent a model system to investigate hormonal control of hGH synthesis and secretion.
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MESH Headings
- Animals
- Cells, Cultured
- Dexamethasone/pharmacology
- Female
- Ghrelin/pharmacology
- Growth Hormone-Releasing Hormone/pharmacology
- Human Growth Hormone/genetics
- Human Growth Hormone/metabolism
- Humans
- Immunohistochemistry
- Male
- Mice
- Mice, Transgenic
- Models, Biological
- Pituitary Gland/cytology
- Pituitary Gland/drug effects
- Pituitary Gland/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Ghrelin/genetics
- Receptors, Ghrelin/metabolism
- Receptors, Neuropeptide/genetics
- Receptors, Neuropeptide/metabolism
- Receptors, Pituitary Hormone-Regulating Hormone/genetics
- Receptors, Pituitary Hormone-Regulating Hormone/metabolism
- Thyroid Hormones/pharmacology
- Triiodothyronine/pharmacology
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Affiliation(s)
- Hana Vakili
- Department of Physiology, University of Manitoba, Canada
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13
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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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14
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Davis SW, Castinetti F, Carvalho LR, Ellsworth BS, Potok MA, Lyons RH, Brinkmeier ML, Raetzman LT, Carninci P, Mortensen AH, Hayashizaki Y, Arnhold IJP, Mendonça BB, Brue T, Camper SA. Molecular mechanisms of pituitary organogenesis: In search of novel regulatory genes. Mol Cell Endocrinol 2010; 323:4-19. [PMID: 20025935 PMCID: PMC2909473 DOI: 10.1016/j.mce.2009.12.012] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Defects in pituitary gland organogenesis are sometimes associated with congenital anomalies that affect head development. Lesions in transcription factors and signaling pathways explain some of these developmental syndromes. Basic research studies, including the characterization of genetically engineered mice, provide a mechanistic framework for understanding how mutations create the clinical characteristics observed in patients. Defects in BMP, WNT, Notch, and FGF signaling pathways affect induction and growth of the pituitary primordium and other organ systems partly by altering the balance between signaling pathways. The PITX and LHX transcription factor families influence pituitary and head development and are clinically relevant. A few later-acting transcription factors have pituitary-specific effects, including PROP1, POU1F1 (PIT1), and TPIT (TBX19), while others, such as NeuroD1 and NR5A1 (SF1), are syndromic, influencing development of other endocrine organs. We conducted a survey of genes transcribed in developing mouse pituitary to find candidates for cases of pituitary hormone deficiency of unknown etiology. We identified numerous transcription factors that are members of gene families with roles in syndromic or non-syndromic pituitary hormone deficiency. This collection is a rich source for future basic and clinical studies.
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Affiliation(s)
- S W Davis
- University of Michigan Medical School, Ann Arbor, MI 41809-5618, 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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Almuly R, Skopal T, Funkenstein B. Regulatory regions in the promoter and first intron of Sparus aurata growth hormone gene: Repression of gene activity by a polymorphic minisatellite. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2008; 3:43-50. [DOI: 10.1016/j.cbd.2006.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 12/05/2006] [Accepted: 12/07/2006] [Indexed: 10/23/2022]
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Cattini PA, Yang X, Jin Y, Detillieux KA. Regulation of the human growth hormone gene family: possible role for Pit-1 in early stages of pituitary-specific expression and repression. Neuroendocrinology 2006; 83:145-53. [PMID: 17047377 DOI: 10.1159/000095522] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The somatic cells of a multicellular organism contain an identical complement of genes that need to be expressed specifically and appropriately to allow the normal development and functions associated with an organism. In the eukaryotic cell nucleus, genes are packaged with nucleoprotein histones into chromatin. The human growth hormone (GH)/chorionic somatomammotropin (CS) gene family offers an excellent model to study the relationship between chromatin structure and transcription factor binding in terms of tissue-specific gene expression. The GH/CS gene family consists of five genes (GH-N, GH-V, CS-A, CS-B and CS-L), contained in a single locus on chromosome 17. Although they share approximately 94% sequence similarity, GH-N expression is restricted to pituitary somatotropes while the four placental GH/CS genes are expressed in the villus syncytiotrophoblast. Appropriate expression in vivo is dependent on remote sequences found 14-32 kb upstream of GH-N in the loci of adjacent genes, and these sequences are characterized by five (I-V) nuclease-hypersensitive sites (HS). Pituitary-specific factor Pit-1 binds at HS I/II and plays an essential role in chromatin remodeling and GH-N expression; however, the processes that lead to HS I/II accessibility are unknown. We discuss the possibility that Pit-1-driven remodeling at HS III may precede that at HS I/II in the pituitary. Also, in pituitary chromatin, all five GH/CS genes share similar nuclease sensitivity, suggesting that the conformation of the placental genes is not inhibitory to transcription. Given that the promoters of both GH-N and the placental GH/CS genes contain Pit-1-binding sites, possible mechanisms to restrict placenta GH/CS promoter activity in the pituitary are discussed, including active repression via P sequences located upstream of each of the placental GH/CS genes. Positively or negatively influencing those components known to be important for pituitary transcription may link epigenetic events to key transcription factors in the overall picture of tissue-specific control of gene expression.
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Affiliation(s)
- Peter A Cattini
- Department of Physiology, University of Manitoba, Winnipeg, Canada.
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