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Nancy R Manley - One of the best experts on this subject based on the ideXlab platform.
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Embryology of the Parathyroid Glands
Endocrinology and metabolism clinics of North America, 2018Co-Authors: Kristen Peissig, Brian G. Condie, Nancy R ManleyAbstract:The parathyroid glands are essential for regulating calcium homeostasis in the body. The genetic programs that control parathyroid fate specification, morphogenesis, differentiation, and survival are only beginning to be delineated, but are all centered around a key transcription factor, GCM2. Mutations in the GCM2 gene as well as in several other genes involved in parathyroid organogenesis have been found to cause parathyroid disorders in humans. Therefore, understanding the normal development of the parathyroid will provide insight into the origins of parathyroid disorders.
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Determining the effect of BMP signaling on thymus fate specification and differentiation of the third pharyngeal pouch in the mouse. (HEM7P.235)
Journal of Immunology, 2015Co-Authors: Trent Frisbie, John D. O'neil, Julie Gordon, Steven A. Vokes, Ellen R. Richie, Nancy R ManleyAbstract:The third pharyngeal pouch is an endodermally derived epithelium that differentiates into thymus and parathyroid cells. Foxn1 (transcription factor) is a thymus-specific marker, which is required for thymic epithelial cell (TEC) proliferation and differentiation. GCM2 is a parathyroid-specific marker, which is essential for parathyroid survival and differentiation. Loss of function genetic analysis of BMP4 showed that BMP4 is required for organ morphogenesis but not initial thymus fate; however, repression of BMP signaling by transgenic expression of ectopic Noggin inhibitor suppressed Foxn1expression. Based on these data, we hypothesize that BMP signaling is necessary for normal thymus fate specification during initial organogenesis with BMP signaling promoting thymus fate while inhibiting parathyroid fate. We are testing this hypothesis using inducible Gremlin transgenic mice in a tissue-specific Cre-Lox induction system, as well as gain and loss of function experiments in embryo cultures. Current data suggest delayed expression of Foxn1 when Gremlin is ectopically expressed. Explant cultures with dorsomorphin, a BMP inhibiting drug, showed a reduction of both GCM2 and Foxn1 . Also, cultured embryos with a BMP4 bead implant showed a reduction of GCM2 . Surprisingly, these data suggest inhibition of BMP signaling is suppressing GCM2, while supporting the hypothesis that BMP signaling is necessary for initial thymus fate specification.
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Thymus-Associated Parathyroid Hormone Has Two Cellular Origins with Distinct Endocrine and Immunological Functions
2013Co-Authors: Zhijie Liu, Alison Farley, Beth J. Kirby, Clare C Blackburn, Lizhen Chen, Christopher S Kovacs, Nancy R ManleyAbstract:In mammals, parathyroid hormone (PTH) is a key regulator of extracellular calcium and inorganic phosphorus homeostasis. Although the parathyroid glands were thought to be the only source of PTH, extra-parathyroid PTH production in the thymus, which shares a common origin with parathyroids during organogenesis, has been proposed to provide an auxiliary source of PTH, resulting in a higher than expected survival rate for aparathyroid GCM2 2/2 mutants. However, the developmental ontogeny and cellular identity of these ‘‘thymic’ ’ PTH–expressing cells is unknown. We found that the lethality of aparathyroid GCM2 2/2 mutants was affected by genetic background without relation to serum PTH levels, suggesting a need to reconsider the physiological function of thymic PTH. We identified two sources of extra-parathyroid PTH in wild-type mice. Incomplete separation of the parathyroid and thymus organs during organogenesis resulted in misplaced, isolated parathyroid cells that were often attached to the thymus; this was the major source of thymic PTH in normal mice. Analysis of thymus and parathyroid organogenesis in human embryos showed a broadly similar result, indicating that these results may provide insight into human parathyroid development. In addition, medullary thymic epithelial cells (mTECs) express PTH in a GCM2-independent manner that requires TEC differentiation and is consistent with expression as a self-antigen for negative selection. Genetic or surgical removal of the thymus indicated that thymus-derived PTH in GCM2 2/2 mutants did not provide auxiliary endocrine function. Our data show conclusively that the thymus does no
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thymus associated parathyroid hormone has two cellular origins with distinct endocrine and immunological functions
PLOS Genetics, 2010Co-Authors: Alison Farley, Beth J. Kirby, Clare C Blackburn, Lizhen Chen, Christopher S Kovacs, Nancy R ManleyAbstract:In mammals, parathyroid hormone (PTH) is a key regulator of extracellular calcium and inorganic phosphorus homeostasis. Although the parathyroid glands were thought to be the only source of PTH, extra-parathyroid PTH production in the thymus, which shares a common origin with parathyroids during organogenesis, has been proposed to provide an auxiliary source of PTH, resulting in a higher than expected survival rate for aparathyroid GCM2−/− mutants. However, the developmental ontogeny and cellular identity of these “thymic” PTH–expressing cells is unknown. We found that the lethality of aparathyroid GCM2−/− mutants was affected by genetic background without relation to serum PTH levels, suggesting a need to reconsider the physiological function of thymic PTH. We identified two sources of extra-parathyroid PTH in wild-type mice. Incomplete separation of the parathyroid and thymus organs during organogenesis resulted in misplaced, isolated parathyroid cells that were often attached to the thymus; this was the major source of thymic PTH in normal mice. Analysis of thymus and parathyroid organogenesis in human embryos showed a broadly similar result, indicating that these results may provide insight into human parathyroid development. In addition, medullary thymic epithelial cells (mTECs) express PTH in a GCM2-independent manner that requires TEC differentiation and is consistent with expression as a self-antigen for negative selection. Genetic or surgical removal of the thymus indicated that thymus-derived PTH in GCM2−/− mutants did not provide auxiliary endocrine function. Our data show conclusively that the thymus does not serve as an auxiliary source of either serum PTH or parathyroid function. We further show that the normal process of parathyroid organogenesis in both mice and humans leads to the generation of multiple small parathyroid clusters in addition to the main parathyroid glands, that are the likely source of physiologically relevant “thymic PTH.”
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GCM2 is required for the differentiation and survival of parathyroid precursor cells in the parathyroid thymus primordia
Developmental Biology, 2007Co-Authors: Zhijie Liu, Nancy R ManleyAbstract:Abstract The parathyroid glands develop with the thymus from bilateral common primordia that develop from the 3rd pharyngeal pouch endoderm in mouse embryos at about E11, each of which separates into one parathyroid gland and one thymus lobe by E13.5. GCM2, a mouse ortholog of the Drosophila Glial Cells Missing gene, is expressed in the parathyroid-specific domains in the 3rd pouches from E9.5. The null mutation of GCM2 causes aparathyroidism in the fetal and adult mouse and has been proposed to be a master regulator for parathyroid development. In order to study how GCM2 functions in parathyroid development, we investigated the mechanism that causes the loss of parathyroids in GCM2 null mutants. Analysis of the 3rd pouch-derived primordium in GCM2−/− mutants showed the parathyroid-specific domain was present before E12.5 but underwent programmed cell death between E12 and 12.5. RNA and protein localization studies for parathyroid hormone (Pth) in wild-type embryos showed that the presumptive parathyroid domain in the parathyroid/thymus primordia started to transcribe Pth mRNA and produce PTH protein from E11.5 before the separation of parathyroid and thymus domains. However in GCM2−/− mutants, the parathyroid-specific domain in the common primordium did not express Pth and could not maintain the expression of two other parathyroid marker genes, CasR and CCL21, although expression of these two genes was initiated. Marker gene analysis placed GCM2 downstream of the known transcription and signaling pathways for parathyroid/thymus organogenesis. These results suggest that GCM2 is not required for pouch patterning or to establish the parathyroid domain, but is required for differentiation and subsequent survival of parathyroid cells.
Hungwen Chen - One of the best experts on this subject based on the ideXlab platform.
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new insights into the regulation of placental growth factor gene expression by the transcription factors gcm1 and dlx3 in human placenta
Journal of Biological Chemistry, 2018Co-Authors: Yueh Ho Chiu, Geen-dong Chang, Hungwen Chen, Mingren Yang, Liangjie Wang, Minghon ChenAbstract:: Expression of placental growth factor (PGF) is closely associated with placental perfusion in early pregnancy. PGF is primarily expressed in placental trophoblasts, and its expression decreases in preeclampsia, associated with placental hypoxia. The transcription factors glial cells missing 1 (GCM1) and metal-regulatory transcription factor 1 (MTF1) have been implicated in the regulation of PGF gene expression through regulatory elements upstream and downstream of the PGF transcription start site, respectively. Here, we clarified the mechanism underlying placenta-specific PGF expression. We demonstrate that GCM1 up-regulates PGF expression through three downstream GCM1-binding sites (GBSs) but not a previously reported upstream GBS. Interestingly, we also found that these downstream GBSs also harbor metal-response elements for MTF1. Surprisingly, however, we observed that MTF1 is unlikely to regulate PGF expression in the placenta because knockdown or overexpression of GCM1, but not MTF1, dramatically decreased PGF expression or reversed the suppression of PGF expression under hypoxia, respectively. We also demonstrate that another transcription factor, Distal-less homeobox 3 (DLX3), interacts with the DNA-binding domain and the first transactivation domain of GCM1 and that this interaction inhibits GCM1-mediated PGF expression. Moreover, the GCM1-DLX3 interaction interfered with CREB-binding protein-mediated GCM1 acetylation and activation. In summary, we have identified several GBSs in the PGF promoter that are highly responsive to GCM1, have demonstrated that MTF1 does not significantly regulate PGF expression in placental cells, and provide evidence that DLX3 inhibits GCM1-mediated PGF expression. Our findings revise the mechanism for GCM1- and DLX3-mediated regulation of PGF gene expression.
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GATA3 inhibits GCM1 activity and trophoblast cell invasion
Scientific reports, 2016Co-Authors: Yueh Ho Chiu, Hungwen ChenAbstract:Development of human placenta involves the invasion of trophoblast cells from anchoring villi into the maternal decidua. Placental transcription factor GCM1 regulates trophoblast cell invasion via transcriptional activation of HtrA4 gene, which encodes a serine protease enzyme. The GATA3 transcription factor regulates trophoblast cell differentiation and is highly expressed in invasive murine trophoblast giant cells. The regulation of trophoblastic invasion by GCM1 may involve novel cellular factors. Here we show that GATA3 interacts with GCM1 and inhibits its activity to suppress trophoblastic invasion. Immunohistochemistry demonstrates that GATA3 and GCM1 are coexpressed in villous cytotrophoblast cells, syncytiotrophoblast layer and extravillous trophoblast cells of human placenta. Interestingly, GATA3 interacts with GCM1, but not the GCM2 homologue, through the DNA-binding domain and first transcriptional activation domain in GCM1 and the transcriptional activation domains and zinc finger 1 domain in GATA3. While GATA3 did not affect DNA-binding activity of GCM1, it suppressed transcriptional activity of GCM1 and therefore HtrA4 promoter activity. Correspondingly, GATA3 knockdown elevated HtrA4 expression in BeWo and JEG-3 trophoblast cell lines and enhanced the invasion activities of both lines. This study uncovered a new GATA3 function in placenta as a negative regulator of GCM1 activity and trophoblastic invasion.
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Involvement of Epac1/Rap1/CaMKI/ HDAC5 signaling cascade in the regulation of placental cell fusion
Molecular Human Reproduction, 2013Co-Authors: Ching-wen Chang, Mei-leng Cheong, Geen-dong Chang, Ming-song Tsai, Hungwen ChenAbstract:The placental transcription factor glial cell missing 1 (GCM1) and its target gene syncytin-1 are involved in cAMP-stimulated trophoblastic fusion for syncytiotrophoblast formation. GCM1 DNA-binding activity is inhibited by sumoylation, whereas GCM1 stability is decreased by deacetylation. cAMP enhances GCM1 desumoylation through the Epac1/Rap1/CaMKI signaling cascade and CaMKI is known to down-regulate class IIa HDAC activity. In this paper, we study whether the Epac1/Rap1/CaMKI signaling cascade regulates GCM1 activity and placental cell fusion through class IIa HDACs. Interaction and co-localization of GCM1 and HDAC5 were characterized by co-immunopre- cipitation analysis and immunofluorescence microscopy (IFM). Regulation of GCM1 transcription activity and syncytin-1 expression by HDAC5 was studied by transient expression. Phospho-specific antibodies against HDAC5, RNA interference and IFM were used to examine the de- repression of GCM1 activity, syncytin-1 expression and cell-cell fusion by Epac1/Rap1/CaMKI signaling cascade in placental BeWo cells expressing constitutively active Epac1 and CaMKI. We demonstrate that both GCM1 and HDAC5 are expressed in the syncytiotrophoblast layer of full-term placenta and the nuclei of BeWo cells. The interaction between HDAC5 and GCM1 facilitates GCM1 deacetylation and sup- presses its transcriptional activity. In contrast, Epac1 stimulates HDAC5 phosphorylation on Ser259 and Ser498 in a Rap1- and CaMKI-dependent manner leading to nuclear export of HDAC5 and thereby de-repression of GCM1 transcriptional activity. Importantly, HDAC5 suppresses syncytin-1 expression and cell-cell fusion in BeWo cells, which is counteracted by Epac1 and CaMKI. Our results reveal a new layer of regulation of GCM1 activity and placental cell fusion through the Epac1/Rap1/CaMKI signaling cascade by restraining HDAC5 from interacting with and mediating GCM1 deacetylation.
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RACK1 (receptor for activated C-kinase 1) interacts with FBW2 (F-box and WD-repeat domain-containing 2) to up-regulate GCM1 (glial cell missing 1) stability and placental cell migration and invasion
The Biochemical journal, 2013Co-Authors: Chang‑chun Wang, Shu-yu Lin, Hungwen ChenAbstract:GCM1 (glial cell missing 1) is a short-lived transcription factor essential for placental development. The F-box protein, FBW2 (F-box and WD-repeat domain-containing 2), which contains five WD (tryptophan-aspartate) repeats, recognizes GCM1 and mediates its ubiquitination via the SCFFBW2 E3 ligase complex. Although the interaction between GCM1 and FBW2 is facilitated by GCM1 phosphorylation, it is possible that this interaction might be regulated by additional cellular factors. In the present study, we perform tandem-affinity purification coupled with MS analysis identifying RACK1 (receptor for activated C-kinase 1) as an FBW2-interacting protein. RACK1 is a multifaceted scaffold protein containing seven WD repeats. We demonstrate that the WD repeats in both RACK1 and FBW2 are required for the interaction of RACK1 and FBW2. Furthermore, RACK1 competes with GCM1 for FBW2 and thereby prevents GCM1 ubiquitination, which is also supported by the observation that GCM1 is destabilized in RACK1-knockdown BeWo placental cells. Importantly, RACK1 knockdown leads to decreased expression of the GCM1 target gene HTRA4 (high-temperature requirement protein A4), which encodes a serine protease crucial for cell migration and invasion. As a result, migration and invasion activities are down-regulated in RACK1-knockdown BeWo cells. The present study reveals a novel function for RACK1 to regulate GCM1 activity and placental cell migration and invasion.
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Dual-specificity phosphatase 23 mediates GCM1 dephosphorylation and activation
Nucleic Acids Research, 2010Co-Authors: Ching-wen Chang, Mei-leng Cheong, Hsei-chorn Chen, Geen-dong Chang, Hungwen ChenAbstract:Glial cells missing homolog 1 (GCM1) is a transcription factor essential for placental development. GCM1 promotes syncytiotrophoblast formation and placental vasculogenesis by activating fusogenic and proangiogenic gene expression in placenta. GCM1 activity is regulated by multiple post-translational modifications. The cAMP/PKA-signaling pathway promotes CBP-mediated GCM1 acetylation and stabilizes GCM1, whereas hypoxia-induced GSK-3β-mediated phosphorylation of Ser322 causes GCM1 ubiquitination and degradation. How and whether complex modifications of GCM1 are coordinated is not known. Here we show that the interaction of GCM1 and dual-specificity phosphatase 23 (DUSP23) is enhanced by PKA-dependent phosphorylation of GCM1 on Ser269 and Ser275. The recruitment of DUSP23 reverses GSK-3β-mediated Ser322 phosphorylation, which in turn promotes GCM1 acetylation, stabilization and activation. Supporting a central role in coordinating GCM1 modifications, knockdown of DUSP23 suppressed GCM1 target gene expression and placental cell fusion. Our study identifies DUSP23 as a novel factor that promotes placental cell fusion and reveals a complex regulation of GCM1 activity by coordinated phosphorylation, dephosphorylation and acetylation.
Lucie Canaff - One of the best experts on this subject based on the ideXlab platform.
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Calcium-Sensing Receptor Gene: Regulation of Expression.
Frontiers in physiology, 2016Co-Authors: Geoffrey N Hendy, Lucie CanaffAbstract:The human calcium-sensing receptor gene (CASR) has 8 exons, and localizes to chromosome 3q. Exons 1A and 1B encode alternative 5’-untranslated regions (UTRs) that splice to exon 2 encoding the AUG initiation codon. Exons 2-7 encode the CaSR protein of 1078 amino acids. Promoter P1 has TATA and CCAAT boxes upstream of exon 1A, and promoter P2 has Sp1/3 motifs at the start site of exon 1B. Exon 1A transcripts from the P1 promoter are reduced in parathyroid tumors and colon carcinomas. Studies of colon carcinomas and neuroblastomas have emphasized the importance of epigenetic changes – promoter methylation of the GC-rich P2 promoter, histone acetylation – as well as involvement of microRNAs in bringing about CASR gene silencing and reduced CaSR expression. Functional cis-elements in the CASR promoters responsive to 1,25-dihydroxyvitamin D [1,25(OH)2D], proinflammatory cytokines, and the transcription factor glial cells missing-2 (GCM2) have been characterized. Reduced levels of CaSR and reduced responsiveness to active vitamin D in parathyroid neoplasia and colon carcinoma may blunt the “tumor suppressor” activity of the CaSR. The hypocalcemia of critically ill patients with burn injury or sepsis is associated with CASR gene upregulation by TNF-alpha and IL-1beta via kappaB elements, and by IL-6 via Stat1/3 and Sp1/3 elements in the CASR gene promoters, respectively. The CASR is transactivated by GCM2 – the expression of which is essential for parathyroid gland development. Hyperactive forms of GCM2 may contribute to later parathyroid hyperactivity or tumorigenesis. The expression of the CaSR––the calciostat––is regulated physiologically and pathophysiologically at the gene level.
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Increased Prevalence of the GCM2 Polymorphism, Y282D, in Primary Hyperparathyroidism: Analysis of Three Italian Cohorts
The Journal of clinical endocrinology and metabolism, 2014Co-Authors: Leonardo D'agruma, Lucie Canaff, Michela Coco, Vito Guarnieri, Claudia Battista, Antonio Stefano Salcuni, Sabrina Corbetta, Filomena Cetani, Salvatore Minisola, Iacopo ChiodiniAbstract:Context: Glial cells missing-2 (GCM2) is key for parathyroid gland organogenesis. Its persistent expression in the adult parathyroid raises the possibility that overactive forms play a role in the evolution of parathyroid hyperactivity or tumorigenesis. A GCM2 c.844T→G; p.Y282D missense variant has been described within a transactivation inhibitory domain (amino acids 263–352). Objective: The aims of the study were to 1) assess the frequency of Y282D in Italian primary hyperparathyroidism (PHPT) and control (C) populations, 2) test for association of 282D with PHPT and its phenotypic features, and 3) compare the transactivation potency of GCM2 282D relative to wild-type Y282. Subjects and Methods: Subjects included a large southern Italian cohort (310 PHPT and 433 C) and 2 replication cohorts from northern Italy. Association of 282D with PHPT was tested in all cohorts and with phenotypic features in the larger PHPT cohort. An in vitro GCM promoter-luciferase reporter assay was conducted in HEK293 cells. R...
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glial cells missing 2 GCM2 transactivates the calcium sensing receptor gene effect of a dominant negative GCM2 mutant associated with autosomal dominant hypoparathyroidism
Human Mutation, 2009Co-Authors: Lucie Canaff, Xiang Zhou, Irina Mosesova, David E C Cole, Geoffrey N HendyAbstract:Glial cells missing-2 (GCM2) is a transcription factor expressed in the parathyroid hormone (PTH)-secreting cells of the parathyroid gland and is essential for their development. Thus far, downstream targets of GCM2 have not been identified. Here, we show that both promoters (P1 and P2) of the calcium-sensing receptor (CASR) gene, a differentiation marker for the parathyroid gland, are transactivated by wild-type GCM2. GCM response elements within CASR P1 (–451 to –441; relative to the transcription start site at +1) and CASR P2 (–166 to –156) were identified by mutated promoter-reporter studies as well as oligonucleotide precipitation assays. Primary hypoparathyroidism is a heterogeneous group of conditions characterized by hypocalcemia and hyperphosphatemia due to deficient PTH secretion. A few cases of familial isolated hypoparathyroidism with autosomal recessive inheritance have been identified that are caused by homozygous inactivating mutations in the GCM2 gene. We describe the GCM2 mutations in two families with hypoparathyroidism, one inherited in an autosomal recessive fashion and the other in an autosomal dominant manner. In transfection studies using a promoter-reporter construct having synthetic multimerized GCM elements in the promoter, the dominantly inherited mutant GCM2 exerted a dominant-negative effect on wild-type GCM2 activity, whereas recessively inherited mutants did not. In addition, we show that the transactivation of the CASR promoter-reporter constructs by wild-type GCM2 is completely abolished in the presence of the dominant-negative mutant GCM2. Hum Mutat 0,1–8, 2008. © 2008 Wiley-Liss, Inc.
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Glial cells missing-2 (GCM2) transactivates the calcium-sensing receptor gene: effect of a dominant-negative GCM2 mutant associated with autosomal dominant hypoparathyroidism.
Human mutation, 2009Co-Authors: Lucie Canaff, Xiang Zhou, Irina Mosesova, David E C Cole, Geoffrey N HendyAbstract:Glial cells missing-2 (GCM2) is a transcription factor expressed in the parathyroid hormone (PTH)-secreting cells of the parathyroid gland and is essential for their development. Thus far, downstream targets of GCM2 have not been identified. Here, we show that both promoters (P1 and P2) of the calcium-sensing receptor (CASR) gene, a differentiation marker for the parathyroid gland, are transactivated by wild-type GCM2. GCM response elements within CASR P1 (-451 to -441; relative to the transcription start site at +1) and CASR P2 (-166 to -156) were identified by mutated promoter-reporter studies as well as oligonucleotide precipitation assays. Primary hypoparathyroidism is a heterogeneous group of conditions characterized by hypocalcemia and hyperphosphatemia due to deficient PTH secretion. A few cases of familial isolated hypoparathyroidism with autosomal recessive inheritance have been identified that are caused by homozygous inactivating mutations in the GCM2 gene. We describe the GCM2 mutations in two families with hypoparathyroidism, one inherited in an autosomal recessive fashion and the other in an autosomal dominant manner. In transfection studies using a promoter-reporter construct having synthetic multimerized GCM elements in the promoter, the dominantly inherited mutant GCM2 exerted a dominant-negative effect on wild-type GCM2 activity, whereas recessively inherited mutants did not. In addition, we show that the transactivation of the CASR promoter-reporter constructs by wild-type GCM2 is completely abolished in the presence of the dominant-negative mutant GCM2.
Geoffrey N Hendy - One of the best experts on this subject based on the ideXlab platform.
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Calcium-Sensing Receptor Gene: Regulation of Expression.
Frontiers in physiology, 2016Co-Authors: Geoffrey N Hendy, Lucie CanaffAbstract:The human calcium-sensing receptor gene (CASR) has 8 exons, and localizes to chromosome 3q. Exons 1A and 1B encode alternative 5’-untranslated regions (UTRs) that splice to exon 2 encoding the AUG initiation codon. Exons 2-7 encode the CaSR protein of 1078 amino acids. Promoter P1 has TATA and CCAAT boxes upstream of exon 1A, and promoter P2 has Sp1/3 motifs at the start site of exon 1B. Exon 1A transcripts from the P1 promoter are reduced in parathyroid tumors and colon carcinomas. Studies of colon carcinomas and neuroblastomas have emphasized the importance of epigenetic changes – promoter methylation of the GC-rich P2 promoter, histone acetylation – as well as involvement of microRNAs in bringing about CASR gene silencing and reduced CaSR expression. Functional cis-elements in the CASR promoters responsive to 1,25-dihydroxyvitamin D [1,25(OH)2D], proinflammatory cytokines, and the transcription factor glial cells missing-2 (GCM2) have been characterized. Reduced levels of CaSR and reduced responsiveness to active vitamin D in parathyroid neoplasia and colon carcinoma may blunt the “tumor suppressor” activity of the CaSR. The hypocalcemia of critically ill patients with burn injury or sepsis is associated with CASR gene upregulation by TNF-alpha and IL-1beta via kappaB elements, and by IL-6 via Stat1/3 and Sp1/3 elements in the CASR gene promoters, respectively. The CASR is transactivated by GCM2 – the expression of which is essential for parathyroid gland development. Hyperactive forms of GCM2 may contribute to later parathyroid hyperactivity or tumorigenesis. The expression of the CaSR––the calciostat––is regulated physiologically and pathophysiologically at the gene level.
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glial cells missing 2 GCM2 transactivates the calcium sensing receptor gene effect of a dominant negative GCM2 mutant associated with autosomal dominant hypoparathyroidism
Human Mutation, 2009Co-Authors: Lucie Canaff, Xiang Zhou, Irina Mosesova, David E C Cole, Geoffrey N HendyAbstract:Glial cells missing-2 (GCM2) is a transcription factor expressed in the parathyroid hormone (PTH)-secreting cells of the parathyroid gland and is essential for their development. Thus far, downstream targets of GCM2 have not been identified. Here, we show that both promoters (P1 and P2) of the calcium-sensing receptor (CASR) gene, a differentiation marker for the parathyroid gland, are transactivated by wild-type GCM2. GCM response elements within CASR P1 (–451 to –441; relative to the transcription start site at +1) and CASR P2 (–166 to –156) were identified by mutated promoter-reporter studies as well as oligonucleotide precipitation assays. Primary hypoparathyroidism is a heterogeneous group of conditions characterized by hypocalcemia and hyperphosphatemia due to deficient PTH secretion. A few cases of familial isolated hypoparathyroidism with autosomal recessive inheritance have been identified that are caused by homozygous inactivating mutations in the GCM2 gene. We describe the GCM2 mutations in two families with hypoparathyroidism, one inherited in an autosomal recessive fashion and the other in an autosomal dominant manner. In transfection studies using a promoter-reporter construct having synthetic multimerized GCM elements in the promoter, the dominantly inherited mutant GCM2 exerted a dominant-negative effect on wild-type GCM2 activity, whereas recessively inherited mutants did not. In addition, we show that the transactivation of the CASR promoter-reporter constructs by wild-type GCM2 is completely abolished in the presence of the dominant-negative mutant GCM2. Hum Mutat 0,1–8, 2008. © 2008 Wiley-Liss, Inc.
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Glial cells missing-2 (GCM2) transactivates the calcium-sensing receptor gene: effect of a dominant-negative GCM2 mutant associated with autosomal dominant hypoparathyroidism.
Human mutation, 2009Co-Authors: Lucie Canaff, Xiang Zhou, Irina Mosesova, David E C Cole, Geoffrey N HendyAbstract:Glial cells missing-2 (GCM2) is a transcription factor expressed in the parathyroid hormone (PTH)-secreting cells of the parathyroid gland and is essential for their development. Thus far, downstream targets of GCM2 have not been identified. Here, we show that both promoters (P1 and P2) of the calcium-sensing receptor (CASR) gene, a differentiation marker for the parathyroid gland, are transactivated by wild-type GCM2. GCM response elements within CASR P1 (-451 to -441; relative to the transcription start site at +1) and CASR P2 (-166 to -156) were identified by mutated promoter-reporter studies as well as oligonucleotide precipitation assays. Primary hypoparathyroidism is a heterogeneous group of conditions characterized by hypocalcemia and hyperphosphatemia due to deficient PTH secretion. A few cases of familial isolated hypoparathyroidism with autosomal recessive inheritance have been identified that are caused by homozygous inactivating mutations in the GCM2 gene. We describe the GCM2 mutations in two families with hypoparathyroidism, one inherited in an autosomal recessive fashion and the other in an autosomal dominant manner. In transfection studies using a promoter-reporter construct having synthetic multimerized GCM elements in the promoter, the dominantly inherited mutant GCM2 exerted a dominant-negative effect on wild-type GCM2 activity, whereas recessively inherited mutants did not. In addition, we show that the transactivation of the CASR promoter-reporter constructs by wild-type GCM2 is completely abolished in the presence of the dominant-negative mutant GCM2.
Zhijie Liu - One of the best experts on this subject based on the ideXlab platform.
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Thymus-Associated Parathyroid Hormone Has Two Cellular Origins with Distinct Endocrine and Immunological Functions
2013Co-Authors: Zhijie Liu, Alison Farley, Beth J. Kirby, Clare C Blackburn, Lizhen Chen, Christopher S Kovacs, Nancy R ManleyAbstract:In mammals, parathyroid hormone (PTH) is a key regulator of extracellular calcium and inorganic phosphorus homeostasis. Although the parathyroid glands were thought to be the only source of PTH, extra-parathyroid PTH production in the thymus, which shares a common origin with parathyroids during organogenesis, has been proposed to provide an auxiliary source of PTH, resulting in a higher than expected survival rate for aparathyroid GCM2 2/2 mutants. However, the developmental ontogeny and cellular identity of these ‘‘thymic’ ’ PTH–expressing cells is unknown. We found that the lethality of aparathyroid GCM2 2/2 mutants was affected by genetic background without relation to serum PTH levels, suggesting a need to reconsider the physiological function of thymic PTH. We identified two sources of extra-parathyroid PTH in wild-type mice. Incomplete separation of the parathyroid and thymus organs during organogenesis resulted in misplaced, isolated parathyroid cells that were often attached to the thymus; this was the major source of thymic PTH in normal mice. Analysis of thymus and parathyroid organogenesis in human embryos showed a broadly similar result, indicating that these results may provide insight into human parathyroid development. In addition, medullary thymic epithelial cells (mTECs) express PTH in a GCM2-independent manner that requires TEC differentiation and is consistent with expression as a self-antigen for negative selection. Genetic or surgical removal of the thymus indicated that thymus-derived PTH in GCM2 2/2 mutants did not provide auxiliary endocrine function. Our data show conclusively that the thymus does no
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GCM2 is required for the differentiation and survival of parathyroid precursor cells in the parathyroid thymus primordia
Developmental Biology, 2007Co-Authors: Zhijie Liu, Nancy R ManleyAbstract:Abstract The parathyroid glands develop with the thymus from bilateral common primordia that develop from the 3rd pharyngeal pouch endoderm in mouse embryos at about E11, each of which separates into one parathyroid gland and one thymus lobe by E13.5. GCM2, a mouse ortholog of the Drosophila Glial Cells Missing gene, is expressed in the parathyroid-specific domains in the 3rd pouches from E9.5. The null mutation of GCM2 causes aparathyroidism in the fetal and adult mouse and has been proposed to be a master regulator for parathyroid development. In order to study how GCM2 functions in parathyroid development, we investigated the mechanism that causes the loss of parathyroids in GCM2 null mutants. Analysis of the 3rd pouch-derived primordium in GCM2−/− mutants showed the parathyroid-specific domain was present before E12.5 but underwent programmed cell death between E12 and 12.5. RNA and protein localization studies for parathyroid hormone (Pth) in wild-type embryos showed that the presumptive parathyroid domain in the parathyroid/thymus primordia started to transcribe Pth mRNA and produce PTH protein from E11.5 before the separation of parathyroid and thymus domains. However in GCM2−/− mutants, the parathyroid-specific domain in the common primordium did not express Pth and could not maintain the expression of two other parathyroid marker genes, CasR and CCL21, although expression of these two genes was initiated. Marker gene analysis placed GCM2 downstream of the known transcription and signaling pathways for parathyroid/thymus organogenesis. These results suggest that GCM2 is not required for pouch patterning or to establish the parathyroid domain, but is required for differentiation and subsequent survival of parathyroid cells.
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GCM2 is required for the differentiation and survival of parathyroid precursor cells in the parathyroid/thymus primordia
Developmental biology, 2007Co-Authors: Zhijie Liu, Nancy R ManleyAbstract:Abstract The parathyroid glands develop with the thymus from bilateral common primordia that develop from the 3rd pharyngeal pouch endoderm in mouse embryos at about E11, each of which separates into one parathyroid gland and one thymus lobe by E13.5. GCM2, a mouse ortholog of the Drosophila Glial Cells Missing gene, is expressed in the parathyroid-specific domains in the 3rd pouches from E9.5. The null mutation of GCM2 causes aparathyroidism in the fetal and adult mouse and has been proposed to be a master regulator for parathyroid development. In order to study how GCM2 functions in parathyroid development, we investigated the mechanism that causes the loss of parathyroids in GCM2 null mutants. Analysis of the 3rd pouch-derived primordium in GCM2−/− mutants showed the parathyroid-specific domain was present before E12.5 but underwent programmed cell death between E12 and 12.5. RNA and protein localization studies for parathyroid hormone (Pth) in wild-type embryos showed that the presumptive parathyroid domain in the parathyroid/thymus primordia started to transcribe Pth mRNA and produce PTH protein from E11.5 before the separation of parathyroid and thymus domains. However in GCM2−/− mutants, the parathyroid-specific domain in the common primordium did not express Pth and could not maintain the expression of two other parathyroid marker genes, CasR and CCL21, although expression of these two genes was initiated. Marker gene analysis placed GCM2 downstream of the known transcription and signaling pathways for parathyroid/thymus organogenesis. These results suggest that GCM2 is not required for pouch patterning or to establish the parathyroid domain, but is required for differentiation and subsequent survival of parathyroid cells.
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Coordination between CCR7- and CCR9-mediated chemokine signals in prevascular fetal thymus colonization
Blood, 2006Co-Authors: Cunlan Liu, Nancy R Manley, Fumi Saito, Martin Lipp, Zhijie Liu, Yu Lei, Shoji Uehara, Paul E. Love, Shunzo Kondo, Yousuke TakahamaAbstract:Thymus seeding by T-lymphoid progenitor cells is a prerequisite for T-cell development. However, molecules guiding thymus colonization and their roles before and after thymus vascularization are unclear. Here we show that mice doubly deficient for chemokine receptors CCR7 and CCR9 were defective specifically in fetal thymus colonization before, but not after, thymus vascularization. The defective prevascular fetal thymus colonization was followed by selective loss of the first wave of T-cell development generating epidermal Vgamma3(+) gammadelta T cells. Unexpectedly, CCL21, a CCR7 ligand, was expressed not by Foxn1-dependent thymic primordium but by GCM2-dependent parathyroid primordium, whereas CCL25, a CCR9 ligand, was predominantly expressed by Foxn1-dependent thymic primordium, revealing the role of the adjacent parathyroid in guiding fetal thymus colonization. These results indicate coordination between GCM2-dependent parathyroid and Foxn1-dependent thymic primordia in establishing CCL21/CCR7- and CCL25/CCR9-mediated chemokine guidance essential for prevascular fetal thymus colonization.
