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Rath MF. Homeobox gene-encoded transcription factors in development and mature circadian function of the rodent pineal gland. J Pineal Res 2024; 76:e12950. [PMID: 38558122 DOI: 10.1111/jpi.12950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 02/15/2024] [Accepted: 03/11/2024] [Indexed: 04/04/2024]
Abstract
Homeobox genes encode transcription factors that are widely known to control developmental processes. This is also the case in the pineal gland, a neuroendocrine brain structure devoted to nighttime synthesis of the hormone melatonin. Thus, in accordance with high prenatal gene expression, knockout studies have identified a specific set of homeobox genes that are essential for development of the pineal gland. However, as a special feature of the pineal gland, homeobox gene expression persists into adulthood, and gene product abundance exhibits 24 h circadian rhythms. Recent lines of evidence show that some homeobox genes even control expression of enzymes catalyzing melatonin synthesis. We here review current knowledge of homeobox genes in the rodent pineal gland and suggest a model for dual functions of homeobox gene-encoded transcription factors in developmental and circadian mature neuroendocrine function.
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Affiliation(s)
- Martin F Rath
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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2
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Carstensen MB, Medvetzky A, Weinberger A, Driever W, Gothilf Y, Rath MF. Genetic ablation of the Bsx homeodomain transcription factor in zebrafish: Impact on mature pineal gland morphology and circadian behavior. J Pineal Res 2022; 72:e12795. [PMID: 35249239 PMCID: PMC9285933 DOI: 10.1111/jpi.12795] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 11/30/2022]
Abstract
The pineal gland is a neuroendocrine structure in the brain, which produces and secretes the hormone melatonin at nighttime and is considered a key element in the circadian clock system. Early morphogenesis of the gland is controlled by a number of transcription factors, some of which remain active in adult life. One of these is the brain-specific homeobox (Bsx), a highly conserved homeodomain transcription factor with a developmental role in the pineal gland of several species, including zebrafish, and regulatory roles in mature pinealocytes of the rat. To determine the role of Bsx in circadian biology, we here examined the effects of a bsx loss-of-function mutation on the pineal gland in adult zebrafish and on behavioral circadian rhythms in larvae. In pineal cell type-specific Gfp/Egfp reporter zebrafish lines, we did not detect fluorescence signals in the pineal area of homozygous (bsx-/- ) mutants. Interestingly, a nonpigmented area on the dorsal surface of the head above the gland, known as the pineal window, was pigmented in the homozygous mutants. Furthermore, a structure corresponding to the pineal gland was not detectable in the midline of the adult brain in histological sections analyzed by Nissl staining and S-antigen immunohistochemistry. Moreover, the levels of pineal transcripts were greatly reduced in bsx-/- mutants, as revealed by quantitative real-time polymerase chain reaction analysis. Notably, analysis of locomotor activity at the larval stage revealed altered circadian rhythmicity in the bsx mutants with periods and phases similar to wildtype, but severely reduced amplitudes in locomotor activity patterns. Thus, Bsx is essential for full development of the pineal gland, with its absence resulting in a phenotype of morphological pineal gland ablation and disrupted circadian behavior.
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Affiliation(s)
- Mikkel Bloss Carstensen
- Department of Neuroscience, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Adar Medvetzky
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Alon Weinberger
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
| | - Wolfgang Driever
- Developmental Biology, Institute Biology, Faculty of BiologyAlbert Ludwig University of FreiburgFreiburgGermany
| | - Yoav Gothilf
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
- Sagol School of NeuroscienceTel Aviv UniversityTel AvivIsrael
| | - Martin Fredensborg Rath
- Department of Neuroscience, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
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3
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Rath MF, Møller M. Radiochemical In Situ Hybridization in Developmental Studies of the Pineal Gland. Methods Mol Biol 2022; 2550:75-84. [PMID: 36180679 DOI: 10.1007/978-1-0716-2593-4_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Radiochemical in situ hybridization enables detection of gene expression in small areas of the brain, such as the developing pineal gland in rodents. The method combines determination of spatial and temporal gene expression profiles with semiquantitative analyses. We here describe the procedure of radiochemical in situ hybridization on the developing rat pineal gland ranging from preparation of fetal tissue for in situ hybridization to principles of quantification.
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Affiliation(s)
| | - Morten Møller
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
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4
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Hertz H, Blancas-Velazquez AS, Rath MF. The role of homeobox gene-encoded transcription factors in regulation of phototransduction: Implementing the primary pinealocyte culture as a photoreceptor model. J Pineal Res 2021; 71:e12753. [PMID: 34129741 DOI: 10.1111/jpi.12753] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/14/2021] [Accepted: 06/14/2021] [Indexed: 10/21/2022]
Abstract
Homeobox genes encode transcription factors controlling development; however, a number of homeobox genes are expressed postnatally specifically in melatonin-producing pinealocytes of the pineal gland and photoreceptors of the retina along with transcripts devoted to melatonin synthesis and phototransduction. Homeobox genes regulate melatonin synthesis in pinealocytes, but some homeobox genes also seem to be involved in regulation of retinal phototransduction. Due to the lack of photoreceptor models, we here introduce the rat pinealocyte culture as an in vitro model for studying retinal phototransduction. Systematic qPCR analyses were performed on the rat retina and pineal gland in 24 hour in vivo series and on primary cultures of rat pinealocytes: All homeobox genes and melatonin synthesis components, as well as nine out of ten phototransduction genes, were readily detectable in all three experimental settings, confirming molecular similarity between cultured pinealocytes and in vivo retinal tissue. 24 hours circadian expression was mostly confined to transcripts in the pineal gland, including a novel rhythm in arrestin (Sag). Individual knockdown of the homeobox genes orthodenticle homeobox 2 (Otx2), cone-rod homeobox (Crx) and LIM homeobox 4 (Lhx4) in pinealocyte culture using siRNA resulted in specific downregulation of transcripts representing all levels of phototransduction; thus, all phototransduction genes studied in culture were affected by one or several siRNA treatments. Histological colocalization of homeobox and phototransduction transcripts in the rat retinal photoreceptor was confirmed by RNAscope in situ hybridization, thus suggesting that homeobox gene-encoded transcription factors control postnatal expression of phototransduction genes in the retinal photoreceptor.
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Affiliation(s)
- Henrik Hertz
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Martin Fredensborg Rath
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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5
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Dumas G, Goubran‐Botros H, Matondo M, Pagan C, Boulègue C, Chaze T, Chamot‐Rooke J, Maronde E, Bourgeron T. Mass-spectrometry analysis of the human pineal proteome during night and day and in autism. J Pineal Res 2021; 70:e12713. [PMID: 33368564 PMCID: PMC8047921 DOI: 10.1111/jpi.12713] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 12/15/2022]
Abstract
The human pineal gland regulates day-night dynamics of multiple physiological processes, especially through the secretion of melatonin. Using mass-spectrometry-based proteomics and dedicated analysis tools, we identify proteins in the human pineal gland and analyze systematically their variation throughout the day and compare these changes in the pineal proteome between control specimens and donors diagnosed with autism. Results reveal diverse regulated clusters of proteins with, among others, catabolic carbohydrate process and cytoplasmic membrane-bounded vesicle-related proteins differing between day and night and/or control versus autism pineal glands. These data show novel and unexpected processes happening in the human pineal gland during the day/night rhythm as well as specific differences between autism donor pineal glands and those from controls.
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Affiliation(s)
- Guillaume Dumas
- Human Genetics and Cognitive FunctionsInstitut PasteurUMR 3571 CNRSUniversity Paris DiderotParisFrance
- Precision Psychiatry and Social Physiology laboratoryCHU Ste‐Justine Research CenterDepartment of PsychiatryUniversity of MontrealQuebecQCCanada
| | - Hany Goubran‐Botros
- Human Genetics and Cognitive FunctionsInstitut PasteurUMR 3571 CNRSUniversity Paris DiderotParisFrance
| | - Mariette Matondo
- Institut PasteurUnité de Spectrométrie de Masse pour la Biologie (MSBio)Centre de Ressources et Recherches Technologiques (C2RT)USR 2000 CNRSParisFrance
| | - Cécile Pagan
- Paris Descartes UniversityParisFrance
- Service de Biochimie et Biologie MoléculaireINSERM U942Hôpital LariboisièreAPHPParisFrance
| | - Cyril Boulègue
- Institut PasteurUnité de Spectrométrie de Masse pour la Biologie (MSBio)Centre de Ressources et Recherches Technologiques (C2RT)USR 2000 CNRSParisFrance
| | - Thibault Chaze
- Institut PasteurUnité de Spectrométrie de Masse pour la Biologie (MSBio)Centre de Ressources et Recherches Technologiques (C2RT)USR 2000 CNRSParisFrance
| | - Julia Chamot‐Rooke
- Institut PasteurUnité de Spectrométrie de Masse pour la Biologie (MSBio)Centre de Ressources et Recherches Technologiques (C2RT)USR 2000 CNRSParisFrance
| | - Erik Maronde
- Institute for Anatomy IIFaculty of MedicineGoethe UniversityFrankfurtGermany
| | - Thomas Bourgeron
- Human Genetics and Cognitive FunctionsInstitut PasteurUMR 3571 CNRSUniversity Paris DiderotParisFrance
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Carstensen MB, Hertz H, Bering T, Møller M, Rohde K, Klein DC, Coon SL, Rath MF. Circadian regulation and molecular role of the Bsx homeobox gene in the adult pineal gland. J Pineal Res 2020; 68:e12629. [PMID: 31808568 PMCID: PMC7122731 DOI: 10.1111/jpi.12629] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/29/2019] [Accepted: 11/30/2019] [Indexed: 11/28/2022]
Abstract
The pineal gland is a neuroendocrine organ responsible for production of the nocturnal hormone melatonin. A specific set of homeobox gene-encoded transcription factors govern pineal development, and some are expressed in adulthood. The brain-specific homeobox gene (Bsx) falls into both categories. We here examined regulation and function of Bsx in the mature pineal gland of the rat. We report that Bsx is expressed from prenatal stages into adulthood, where Bsx transcripts are localized in the melatonin-synthesizing pinealocytes, as revealed by RNAscope in situ hybridization. Bsx transcripts were also detected in the adult human pineal gland. In the rat pineal gland, Bsx was found to exhibit a 10-fold circadian rhythm with a peak at night. By combining in vivo adrenergic stimulation and surgical denervation of the gland in the rat with in vitro stimulation and transcriptional inhibition in cultured pinealocytes, we show that rhythmic expression of Bsx is controlled at the transcriptional level by the sympathetic neural input to the gland acting via adrenergic stimulation with cyclic AMP as a second messenger. siRNA-mediated knockdown (>80% reduction) in pinealocyte cultures revealed Bsx to be a negative regulator of other pineal homeobox genes, including paired box 4 (Pax4), but no effect on genes encoding melatonin-synthesizing enzymes was detected. RNA sequencing analysis performed on siRNA-treated pinealocytes further revealed that downstream target genes of Bsx are mainly involved in developmental processes. Thus, rhythmic Bsx expression seems to govern other developmental regulators in the mature pineal gland.
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Affiliation(s)
- Mikkel B Carstensen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Hertz
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tenna Bering
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Møller
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Rohde
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - David C Klein
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Steven L Coon
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Martin F Rath
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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PABPC1-induced stabilization of BDNF-AS inhibits malignant progression of glioblastoma cells through STAU1-mediated decay. Cell Death Dis 2020; 11:81. [PMID: 32015336 PMCID: PMC6997171 DOI: 10.1038/s41419-020-2267-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 12/29/2022]
Abstract
Glioblastoma is the most common and malignant form of primary central nervous tumor in adults. Long noncoding RNAs (lncRNAs) have been reported to play a pivotal role in modulating gene expression and regulating human tumor’s malignant behaviors. In this study, we confirmed that lncRNA brain-derived neurotrophic factor antisense (BDNF-AS) was downregulated in glioblastoma tissues and cells, interacted and stabilized by polyadenylate-binding protein cytoplasmic 1 (PABPC1). Overexpression of BDNF-AS inhibited the proliferation, migration, and invasion, as well as induced the apoptosis of glioblastoma cells. In the in vivo study, PABPC1 overexpression combined with BDNF-AS overexpression produced the smallest tumor and the longest survival. Moreover, BDNF-AS could elicit retina and anterior neural fold homeobox 2 (RAX2) mRNA decay through STAU1-mediated decay (SMD), and thereby regulated the malignant behaviors glioblastoma cells. Knockdown of RAX2 produced tumor-suppressive function in glioblastoma cells and increased the expression of discs large homolog 5 (DLG5), leading to the activation of the Hippo pathway. In general, this study elucidated that the PABPC1-BDNF-AS-RAX2-DLG5 mechanism may contribute to the anticancer potential of glioma cells and may provide potential therapeutic targets for human glioma.
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8
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Hertz H, Carstensen MB, Bering T, Rohde K, Møller M, Granau AM, Coon SL, Klein DC, Rath MF. The Lhx4 homeobox transcript in the rat pineal gland: Adrenergic regulation and impact on transcripts encoding melatonin-synthesizing enzymes. J Pineal Res 2020; 68:e12616. [PMID: 31609018 PMCID: PMC8408918 DOI: 10.1111/jpi.12616] [Citation(s) in RCA: 9] [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: 07/17/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 12/23/2022]
Abstract
Homeobox genes generally encode transcription factors involved in regulating developmental processes. In the pineal gland, a brain structure devoted to nocturnal melatonin synthesis, a number of homeobox genes are also expressed postnatally; among these is the LIM homeobox 4 gene (Lhx4). We here report that Lhx4 is specifically expressed in the postnatal pineal gland of rats and humans. Circadian analyses revealed a fourfold rhythm in Lhx4 expression in the rat pineal gland, with rhythmic expression detectable from postnatal day 10. Pineal Lhx4 expression was confirmed to be positively driven by adrenergic signaling, as evidenced by in vivo modulation of Lhx4 expression by pharmacological (isoprenaline injection) and surgical (superior cervical ganglionectomy) interventions. In cultured pinealocytes, Lhx4 expression was upregulated by cyclic AMP, a second messenger of norepinephrine. By use of RNAscope technology, Lhx4 transcripts were found to be exclusively localized in melatonin-synthesizing pinealocytes. This prompted us to investigate the possible role of Lhx4 in regulation of melatonin-producing enzymes. By use of siRNA technology, we knocked down Lhx4 by 95% in cultured pinealocytes; this caused a reduction in transcripts encoding the melatonin-producing enzyme arylalkylamine N-acetyl transferase (Aanat). Screening the transcriptome of siRNA-treated pinealocytes by RNAseq revealed a significant impact of Lhx4 on the phototransduction pathway and on transcripts involved in development of the nervous system and photoreceptors. These data suggest that rhythmic expression of Lhx4 in the pineal gland is controlled via an adrenergic-cyclic AMP mechanism and that Lhx4 acts to promote nocturnal melatonin synthesis.
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Affiliation(s)
- Henrik Hertz
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel B Carstensen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tenna Bering
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Rohde
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Møller
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Agnete M Granau
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Steven L Coon
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - David C Klein
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Martin F Rath
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Brachet C, Kozhemyakina EA, Boros E, Heinrichs C, Balikova I, Soblet J, Smits G, Vilain C, Mathers PH. Truncating RAX Mutations: Anophthalmia, Hypopituitarism, Diabetes Insipidus, and Cleft Palate in Mice and Men. J Clin Endocrinol Metab 2019; 104:2925-2930. [PMID: 30811539 PMCID: PMC6543774 DOI: 10.1210/jc.2018-02316] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/22/2019] [Indexed: 11/19/2022]
Abstract
CONTEXT The transcription factor RAX is a paired-type homeoprotein that plays a critical role in eye and forebrain development of vertebrate species. RAX knockout mice have anophthalmia, cleft palate, and an abnormal hypothalamus and display perinatal lethality. In humans, homozygous or compound heterozygous RAX mutations have been reported to cause bilateral microphthalmia or anophthalmia without consistent associated features. Congenital hypopituitarism can be associated with various eye or craniofacial anomalies; however, the co-occurrence of congenital hypopituitarism, anophthalmia, cleft palate, and diabetes insipidus has been very rare. RESULTS We report the case of a child with anophthalmia, congenital hypopituitarism, diabetes insipidus, and bilateral cleft lip and palate who had a homozygous frameshift truncating mutation c.266delC (p.Pro89Argfs*114) in exon 1 of the RAX gene. Rax knockout mice show loss of ventral forebrain structures, pituitary, and basosphenoid bone and palate and a misplaced anterior pituitary gland along the roof of the oral cavity. CONCLUSIONS Our patient's phenotype was more severe than that reported in other patients. Although most of the previously reported patients with RAX mutations showed either a missense or some less severe mutation in at least one of their RAX alleles, our patient was homozygous for truncating mutations that would yield a severe, null protein phenotype. The severity of the genetic defect, the precise match between the knockout mouse and the patient's endocrine phenotypes, and the prominent roles of RAX in eye and pituitary development and diencephalic patterning suggest that the RAX null mutations could fully account for the observed phenotype.
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Affiliation(s)
- Cécile Brachet
- Pediatric Endocrinology Unit, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Brussels, Belgium
| | - Elena A Kozhemyakina
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Otolaryngology, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Ophthalmology, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Emese Boros
- Pediatric Endocrinology Unit, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Brussels, Belgium
| | - Claudine Heinrichs
- Pediatric Endocrinology Unit, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Brussels, Belgium
| | - Irina Balikova
- Pediatric Ophthalmology Unit, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Brussels, Belgium
| | - Julie Soblet
- Department of Genetics, Hôpital Universitaire des Enfants Reine Fabiola, ULB Center of Human Genetics, Université Libre de Bruxelles, Brussels, Belgium
- Department of Genetics, Hôpital Erasme, ULB Center of Human Genetics, Université Libre de Bruxelles, Brussels, Belgium
- Interuniversity Institute of Bioinformatics in Brussels, Université Libre de Bruxelles, Brussels, Belgium
| | - Guillaume Smits
- Department of Genetics, Hôpital Universitaire des Enfants Reine Fabiola, ULB Center of Human Genetics, Université Libre de Bruxelles, Brussels, Belgium
- Department of Genetics, Hôpital Erasme, ULB Center of Human Genetics, Université Libre de Bruxelles, Brussels, Belgium
- Interuniversity Institute of Bioinformatics in Brussels, Université Libre de Bruxelles, Brussels, Belgium
| | - Catheline Vilain
- Department of Genetics, Hôpital Universitaire des Enfants Reine Fabiola, ULB Center of Human Genetics, Université Libre de Bruxelles, Brussels, Belgium
- Department of Genetics, Hôpital Erasme, ULB Center of Human Genetics, Université Libre de Bruxelles, Brussels, Belgium
- Interuniversity Institute of Bioinformatics in Brussels, Université Libre de Bruxelles, Brussels, Belgium
| | - Peter H Mathers
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Otolaryngology, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Ophthalmology, West Virginia University School of Medicine, Morgantown, West Virginia
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia
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10
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Rohde K, Hertz H, Rath MF. Homeobox genes in melatonin-producing pinealocytes: Otx2 and Crx act to promote hormone synthesis in the mature rat pineal gland. J Pineal Res 2019; 66:e12567. [PMID: 30803008 DOI: 10.1111/jpi.12567] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/15/2019] [Accepted: 02/20/2019] [Indexed: 02/03/2023]
Abstract
Homeobox genes encode transcription factors that regulate developmental processes; however, in the pineal gland, a neuroendocrine organ responsible for nocturnal melatonin synthesis, expression of the homeobox genes Otx2 (orthodenticle homeobox 2) and Crx (cone-rod homeobox) persists postnatally. We here show that OTX2 and CRX are exclusively present in melatonin-producing pinealocytes of the rat pineal gland. To understand the roles of Otx2 and Crx in the mature pineal gland, we used siRNA technology in cultured rat pinealocytes with the nocturnal situation mimicked by adding norepinephrine to the culture media. siRNA-induced knockdown of Otx2 was found to reduce expression levels of the enzymes involved in melatonin synthesis at both transcript and protein levels. Similar results were obtained when knocking down Crx. Knocking down Otx2 and Crx simultaneously produced an even larger reduction in both transcript and protein levels of the melatonin-producing enzymes and also reduced the levels of melatonin released to the culture media. These results suggest that Otx2 and Crx, both alone and in combination, act to control pineal melatonin synthesis.
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Affiliation(s)
- Kristian Rohde
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Hertz
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin F Rath
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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11
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Hirai S, Hotta K, Okado H. Developmental Roles and Evolutionary Significance of AMPA-Type Glutamate Receptors. Bioessays 2018; 40:e1800028. [PMID: 30058076 DOI: 10.1002/bies.201800028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 07/02/2018] [Indexed: 11/07/2022]
Abstract
Organogenesis and metamorphosis require the intricate orchestration of multiple types of cellular interactions and signaling pathways. Glutamate (Glu) is an excitatory extracellular signaling molecule in the nervous system, while Ca2+ is a major intracellular signaling molecule. The first Glu receptors to be cloned are Ca2+ -permeable receptors in mammalian brains. Although recent studies have focused on Glu signaling in synaptic mechanisms of the mammalian central nervous system, it is unclear how this signaling functions in development. Our recent article demonstrated that Ca2+ -permeable AMPA-type Glu receptors (GluAs) are essential for formation of a photosensitive organ, development of some neurons, and metamorphosis, including tail absorption and body axis rotation, in ascidian embryos. Based on findings in these embryos and mammalian brains, we formed several hypotheses regarding the evolution of GluAs, the non-synaptic function of Glu, the origin of GluA-positive neurons, and the neuronal network that controls metamorphosis in ascidians.
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Affiliation(s)
- Shinobu Hirai
- Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-0057, Japan
| | - Kohji Hotta
- Faculty of Science and Technology, Department of Biosciences and Informatics, Keio University, Kohoku, Yokohama, 223-8522, Japan
| | - Haruo Okado
- Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-0057, Japan
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12
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Rodgers HM, Huffman VJ, Voronina VA, Lewandoski M, Mathers PH. The role of the Rx homeobox gene in retinal progenitor proliferation and cell fate specification. Mech Dev 2018; 151:18-29. [PMID: 29665410 PMCID: PMC5972075 DOI: 10.1016/j.mod.2018.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/10/2018] [Indexed: 10/17/2022]
Abstract
The Retinal homeobox gene (Rx; also Rax) plays a crucial role in the early development of the vertebrate eye. Germline deletion of Rx in mice results in the failure of optic vesicle formation, leading to anophthalmia. Recent research using conditional mouse knockout models provides some clues to the role of Rx in eye development following optic vesicle formation. However, the functions of Rx in embryonic retinogenesis are still not fully understood. We investigated the function of Rx in the mouse neural retina using a conditional knockout where the Pax6α-Cre driver deletes Rx activity in early retinal progenitors. The deletion of Rx activity causes a loss of retinal lamination, a depletion of retinal progenitors, and a change in retinal cell fate in our conditional knockout model. The deletion of Rx leads to an absence of late-born retinal neurons (rods and bipolar cells) and Müller glia at postnatal ages, as well as a loss of the early-born cone photoreceptors. Decreased BrdU labeling in the Rx-deleted portion of the retina suggests a loss of retinal progenitors via early cell cycle exit, which likely prevents the formation of late-born cells. As early-born cells, cone photoreceptors should not be as affected by early cell cycle exit of retinal progenitors. However, embryonic cone photoreceptor labeling is also markedly reduced in Rx-deleted retinas. Together these data demonstrate the importance of Rx for retinal progenitor proliferation and a specific requirement of Rx for cone formation in mice.
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Affiliation(s)
- H M Rodgers
- Neuroscience Graduate Program, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, WV 26506, United States
| | - V J Huffman
- Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Potomac State College of West Virginia University, Keyser, WV 26726, United States; Department of Otolaryngology, West Virginia University School of Medicine, Morgantown, WV 26506, United States
| | - V A Voronina
- Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Laboratory of Cancer and Developmental Biology, NCI-Frederick, National Institutes of Health, Frederick, MD 21702, United States; Biochemistry and Molecular Biology Graduate Program, West Virginia University School of Medicine, Morgantown, WV 26506, United States
| | - M Lewandoski
- Laboratory of Cancer and Developmental Biology, NCI-Frederick, National Institutes of Health, Frederick, MD 21702, United States
| | - P H Mathers
- Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Department of Otolaryngology, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Department of Ophthalmology, West Virginia University School of Medicine, Morgantown, WV 26506, United States; Department of Biochemistry, West Virginia University School of Medicine, Morgantown, WV 26506, United States.
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13
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Musser JM, Arendt D. Loss and gain of cone types in vertebrate ciliary photoreceptor evolution. Dev Biol 2017; 431:26-35. [DOI: 10.1016/j.ydbio.2017.08.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 08/28/2017] [Accepted: 08/30/2017] [Indexed: 01/09/2023]
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14
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Lu J, Mai G, Liu R, Luo Y, Lu L. Acquired Nonpigmented Vitreous Cyst Associated With Lattice Degeneration. Ophthalmic Surg Lasers Imaging Retina 2017; 48:856-858. [PMID: 29020432 DOI: 10.3928/23258160-20170928-13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 07/19/2017] [Indexed: 11/20/2022]
Abstract
A 63-year-old male presented with a round-shaped floater and visual obscuration in the right eye. Clinical evaluation showed a nonpigmented vitreous cyst connected to a lattice degeneration by a stalk. Immunostaining of the vitreous cyst obtained from vitrectomy showed its origin of retinal neuroepithelium. The cyst was formed by continuous vitreous traction, which might tear up the disrupted retina at the area of lattice degeneration. This report added the lattice degeneration to the list of causes for the acquired vitreous cyst. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:856-858.].
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15
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Rohde K, Bering T, Furukawa T, Rath MF. A modulatory role of the Rax
homeobox gene in mature pineal gland function: Investigating the photoneuroendocrine circadian system of a Rax
conditional knockout mouse. J Neurochem 2017; 143:100-111. [DOI: 10.1111/jnc.14120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 06/09/2017] [Accepted: 06/25/2017] [Indexed: 01/19/2023]
Affiliation(s)
- Kristian Rohde
- Department of Neuroscience; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Tenna Bering
- Department of Neuroscience; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
- Laboratory of Neuropsychiatry; Psychiatric Center Copenhagen; Mental Health Services of the Capital Region of Denmark; Copenhagen Denmark
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology; Institute for Protein Research; Osaka University; Suita Osaka Japan
| | - Martin Fredensborg Rath
- Department of Neuroscience; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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16
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Rath MF, Coon SL, Amaral FG, Weller JL, Møller M, Klein DC. Melatonin Synthesis: Acetylserotonin O-Methyltransferase (ASMT) Is Strongly Expressed in a Subpopulation of Pinealocytes in the Male Rat Pineal Gland. Endocrinology 2016; 157:2028-40. [PMID: 26950199 PMCID: PMC4870883 DOI: 10.1210/en.2015-1888] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The rat pineal gland has been extensively used in studies of melatonin synthesis. However, the cellular localization of melatonin synthesis in this species has not been investigated. Here we focus on the localization of melatonin synthesis using immunohistochemical methods to detect the last enzyme in melatonin synthesis, acetylserotonin O-methyltransferase (ASMT), and in situ hybridization techniques to study transcripts encoding ASMT and two other enzymes in melatonin synthesis, tryptophan hydroxylase (TPH)-1 and aralkylamine N-acetyltransferase. In sections of the rat pineal gland, marked cell-to-cell differences were found in ASMT immunostaining intensity and in the abundance of Tph1, Aanat, and Asmt transcripts. ASMT immunoreactivity was localized to the cytoplasm in pinealocytes in the parenchyma of the superficial pineal gland, and immunopositive pinealocytes were also detected in the pineal stalk and in the deep pineal gland. ASMT was found to inconsistently colocalize with S-antigen, a widely used pinealocyte marker; this colocalization was seen in cells throughout the pineal complex and also in displaced pinealocyte-like cells of the medial habenular nucleus. Inconsistent colocalization between ASMT and TPH protein was also detected in the pineal gland. ASMT protein was not detected in extraepithalamic parts of the central nervous system or in peripheral tissues. The findings in this report are of special interest because they provide reason to suspect that melatonin synthesis varies significantly among individual pinealocytes.
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Affiliation(s)
- Martin F Rath
- Department of Neuroscience and Pharmacology (M.F.R., M.M.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Section on Neuroendocrinology (M.F.R., S.L.C., F.G.A., J.L.W., D.C.K.), Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Steven L Coon
- Department of Neuroscience and Pharmacology (M.F.R., M.M.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Section on Neuroendocrinology (M.F.R., S.L.C., F.G.A., J.L.W., D.C.K.), Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Fernanda G Amaral
- Department of Neuroscience and Pharmacology (M.F.R., M.M.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Section on Neuroendocrinology (M.F.R., S.L.C., F.G.A., J.L.W., D.C.K.), Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Joan L Weller
- Department of Neuroscience and Pharmacology (M.F.R., M.M.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Section on Neuroendocrinology (M.F.R., S.L.C., F.G.A., J.L.W., D.C.K.), Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Morten Møller
- Department of Neuroscience and Pharmacology (M.F.R., M.M.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Section on Neuroendocrinology (M.F.R., S.L.C., F.G.A., J.L.W., D.C.K.), Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - David C Klein
- Department of Neuroscience and Pharmacology (M.F.R., M.M.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark; and Section on Neuroendocrinology (M.F.R., S.L.C., F.G.A., J.L.W., D.C.K.), Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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17
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Rohde K, Rovsing L, Ho AK, Møller M, Rath MF. Circadian dynamics of the cone-rod homeobox (CRX) transcription factor in the rat pineal gland and its role in regulation of arylalkylamine N-acetyltransferase (AANAT). Endocrinology 2014; 155:2966-75. [PMID: 24877634 DOI: 10.1210/en.2014-1232] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The cone-rod homeobox (Crx) gene encodes a transcription factor in the retina and pineal gland. Crx deficiency influences the pineal transcriptome, including a reduced expression of arylalkylamine N-acetyltransferase (Aanat), a key enzyme in nocturnal pineal melatonin production. However, previous functional studies on pineal Crx have been performed in melatonin-deficient mice. In this study, we have investigated the role of Crx in the melatonin-proficient rat pineal gland. The current study shows that pineal Crx transcript levels exhibit a circadian rhythm with a peak in the middle of the night, which is transferred into daily changes in CRX protein. The study further shows that the sympathetic innervation of the pineal gland controls the Crx rhythm. By use of adenovirus-mediated short hairpin RNA gene knockdown targeting Crx mRNA in primary rat pinealocyte cell culture, we here show that intact levels of Crx mRNA are required to obtain high levels of Aanat expression, whereas overexpression of Crx induces Aanat transcription in vitro. This regulatory function of Crx is further supported by circadian analysis of Aanat in the pineal gland of the Crx-knockout mouse. Our data indicate that the rhythmic nature of pineal CRX protein may directly modulate the daily profile of Aanat expression by inducing nighttime expression of this enzyme, thus facilitating nocturnal melatonin synthesis in addition to its role in ensuring a correct tissue distribution of Aanat expression.
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Affiliation(s)
- Kristian Rohde
- Department of Neuroscience and Pharmacology (K.R., L.R., M.M., M.F.R.), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; and Department of Physiology (K.R., A.K.H.), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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18
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Homeobox genes and melatonin synthesis: regulatory roles of the cone-rod homeobox transcription factor in the rodent pineal gland. BIOMED RESEARCH INTERNATIONAL 2014; 2014:946075. [PMID: 24877149 PMCID: PMC4022116 DOI: 10.1155/2014/946075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 04/07/2014] [Indexed: 01/20/2023]
Abstract
Nocturnal synthesis of melatonin in the pineal gland is controlled by a circadian rhythm in arylalkylamine N-acetyltransferase (AANAT) enzyme activity. In the rodent, Aanat gene expression displays a marked circadian rhythm; release of norepinephrine in the gland at night causes a cAMP-based induction of Aanat transcription. However, additional transcriptional control mechanisms exist. Homeobox genes, which are generally known to encode transcription factors controlling developmental processes, are also expressed in the mature rodent pineal gland. Among these, the cone-rod homeobox (CRX) transcription factor is believed to control pineal-specific Aanat expression. Based on recent advances in our understanding of Crx in the rodent pineal gland, we here suggest that homeobox genes play a role in adult pineal physiology both by ensuring pineal-specific Aanat expression and by facilitating cAMP response element-based circadian melatonin production.
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Pak T, Yoo S, Miranda-Angulo AM, Wang H, Blackshaw S. Rax-CreERT2 knock-in mice: a tool for selective and conditional gene deletion in progenitor cells and radial glia of the retina and hypothalamus. PLoS One 2014; 9:e90381. [PMID: 24699247 PMCID: PMC3974648 DOI: 10.1371/journal.pone.0090381] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/28/2014] [Indexed: 11/24/2022] Open
Abstract
To study gene function in neural progenitors and radial glia of the retina and hypothalamus, we developed a Rax-CreERT2 mouse line in which a tamoxifen-inducible Cre recombinase is inserted into the endogenous Rax locus. By crossing Rax-CreER(T2) with the Cre-dependent Ai9 reporter line, we demonstrate that tamoxifen-induced Cre activity recapitulates the endogenous Rax mRNA expression pattern. During embryonic development, Cre recombinase activity in Rax-CreER(T2) is confined to retinal and hypothalamic progenitor cells, as well as progenitor cells of the posterior pituitary. At postnatal time points, selective Cre recombinase activity is seen in radial glial-like cell types in these organs--specifically Müller glia and tanycytes--as well as pituicytes. We anticipate that this line will prove useful for cell lineage analysis and investigation of gene function in the developing and mature retina, hypothalamus and pituitary.
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Affiliation(s)
- Thomas Pak
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sooyeon Yoo
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Ana M. Miranda-Angulo
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Institute of Medical Research, School of Medicine, Universidad de Antioquia, Medellín, Colombia
| | - Hong Wang
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Seth Blackshaw
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Center for High-Throughput Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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20
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The Lhx9 homeobox gene controls pineal gland development and prevents postnatal hydrocephalus. Brain Struct Funct 2014; 220:1497-509. [PMID: 24647753 DOI: 10.1007/s00429-014-0740-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 02/19/2014] [Indexed: 12/16/2022]
Abstract
Lhx9 is a member of the LIM homeobox gene family. It is expressed during mammalian embryogenesis in the brain including the pineal gland. Deletion of Lhx9 results in sterility due to failure of gonadal development. The current study was initiated to investigate Lhx9 biology in the pineal gland. Lhx9 is highly expressed in the developing pineal gland of the rat with transcript abundance peaking early in development; transcript levels decrease postnatally to nearly undetectable levels in the adult, a temporal pattern that is generally similar to that reported for Lhx9 expression in other brain regions. Studies with C57BL/6J Lhx9(-/-) mutant mice revealed marked alterations in brain and pineal development. Specifically, the superficial pineal gland is hypoplastic, being reduced to a small cluster of pinealocytes surrounded by meningeal and vascular tissue. The deep pineal gland and the pineal stalk are also reduced in size. Although the brains of neonatal Lhx9(-/-) mutant mice appear normal, severe hydrocephalus develops in about 70% of the Lhx9(-/-) mice at 5-8 weeks of age; these observations are the first to document that deletion of Lhx9 results in hydrocephalus and as such indicate that Lhx9 contributes to the maintenance of normal brain structure. Whereas hydrocephalus is absent in neonatal Lhx9(-/-)mutant mice, the neonatal pineal gland in these animals is hypoplastic. Accordingly, it appears that Lhx9 is essential for early development of the mammalian pineal gland and that this effect is not secondary to hydrocephalus.
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21
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Tosches MA, Arendt D. The bilaterian forebrain: an evolutionary chimaera. Curr Opin Neurobiol 2013; 23:1080-9. [PMID: 24080363 DOI: 10.1016/j.conb.2013.09.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/06/2013] [Indexed: 12/14/2022]
Abstract
The insect, annelid and vertebrate forebrains harbour two major centres of output control, a sensory-neurosecretory centre releasing hormones and a primordial locomotor centre that controls the initiation of muscular body movements. In vertebrates, both reside in the hypothalamus. Here, we review recent comparative neurodevelopmental evidence indicating that these centres evolved from separate condensations of neurons on opposite body sides ('apical nervous system' versus 'blastoporal nervous system') and that their developmental specification involved distinct regulatory networks (apical six3 and rx versus mediolateral nk and pax gene-dependent patterning). In bilaterian ancestors, both systems approached each other and became closely intermingled, physically, functionally and developmentally. Our 'chimeric brain hypothesis' sheds new light on the vast success and rapid diversification of bilaterian animals in the Cambrian and revises our understanding of brain architecture.
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Affiliation(s)
- Maria Antonietta Tosches
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69012 Heidelberg, Germany
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22
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Rath MF, Rohde K, Klein DC, Møller M. Homeobox genes in the rodent pineal gland: roles in development and phenotype maintenance. Neurochem Res 2013; 38:1100-12. [PMID: 23076630 PMCID: PMC3570627 DOI: 10.1007/s11064-012-0906-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 09/19/2012] [Accepted: 10/04/2012] [Indexed: 12/12/2022]
Abstract
The pineal gland is a neuroendocrine gland responsible for nocturnal synthesis of melatonin. During early development of the rodent pineal gland from the roof of the diencephalon, homeobox genes of the orthodenticle homeobox (Otx)- and paired box (Pax)-families are expressed and are essential for normal pineal development consistent with the well-established role that homeobox genes play in developmental processes. However, the pineal gland appears to be unusual because strong homeobox gene expression persists in the pineal gland of the adult brain. Accordingly, in addition to developmental functions, homeobox genes appear to be key regulators in postnatal phenotype maintenance in this tissue. In this paper, we review ontogenetic and phylogenetic aspects of pineal development and recent progress in understanding the involvement of homebox genes in rodent pineal development and adult function. A working model is proposed for understanding the sequential action of homeobox genes in controlling development and mature circadian function of the mammalian pinealocyte based on knowledge from detailed developmental and daily gene expression analyses in rats, the pineal phenotypes of homebox gene-deficient mice and studies on development of the retinal photoreceptor; the pinealocyte and retinal photoreceptor share features not seen in other tissues and are likely to have evolved from the same ancestral photodetector cell.
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Affiliation(s)
- Martin F Rath
- Department of Neuroscience and Pharmacology, Panum Institute 24.2, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, Copenhagen 2200, Denmark.
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23
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Muranishi Y, Terada K, Furukawa T. An essential role for Rax in retina and neuroendocrine system development. Dev Growth Differ 2012; 54:341-8. [PMID: 22524605 DOI: 10.1111/j.1440-169x.2012.01337.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In vertebrates, the central nervous system (CNS) develops as a highly hierarchical, patterned organ with a vast diversity of neuronal and glial cell types. The vertebrate retina is developmentally a part of the CNS. Establishment of the vertebrate retina requires a series of developmental steps including specification of the anterior neural plate, evagination of the optic vesicles from the ventral forebrain, and differentiation of cells. The transcription factor RAX is a paired-type homeoprotein that plays a critical role in the eye and forebrain development of vertebrate species. Rax is initially expressed in the anterior neural region of developing mouse embryos, and later in the retina, pituitary gland, hypothalamus, and pineal gland. The targeted deletion of Rax in the mouse results in no eye formation and abnormal forebrain formation. In humans, mutations in the RAX gene lead to anophthalmia and microphthalmia. These observations indicate that RAX plays a pivotal role in the establishment of the retina. In addition, recent studies have reported that retina and pituitary gland tissues can be induced in a culture system from embryonic stem cells, using RAX expression as an indicator of neuronal progenitor cells in the induced tissue, and suggesting that the Rax gene is a key factor in neuronal regeneration. This review highlights the biological functions and molecular mechanisms of RAX in retina, pituitary, hypothalamus, and pineal gland development.
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Affiliation(s)
- Yuki Muranishi
- Department of Developmental Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka, 565-0874, Japan
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Molecular analysis of the amphioxus frontal eye unravels the evolutionary origin of the retina and pigment cells of the vertebrate eye. Proc Natl Acad Sci U S A 2012; 109:15383-8. [PMID: 22949670 DOI: 10.1073/pnas.1207580109] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The origin of vertebrate eyes is still enigmatic. The "frontal eye" of amphioxus, our most primitive chordate relative, has long been recognized as a candidate precursor to the vertebrate eyes. However, the amphioxus frontal eye is composed of simple ciliated cells, unlike vertebrate rods and cones, which display more elaborate, surface-extended cilia. So far, the only evidence that the frontal eye indeed might be sensitive to light has been the presence of a ciliated putative sensory cell in the close vicinity of dark pigment cells. We set out to characterize the cell types of the amphioxus frontal eye molecularly, to test their possible relatedness to the cell types of vertebrate eyes. We show that the cells of the frontal eye specifically coexpress a combination of transcription factors and opsins typical of the vertebrate eye photoreceptors and an inhibitory Gi-type alpha subunit of the G protein, indicating an off-responding phototransductory cascade. Furthermore, the pigmented cells match the retinal pigmented epithelium in melanin content and regulatory signature. Finally, we reveal axonal projections of the frontal eye that resemble the basic photosensory-motor circuit of the vertebrate forebrain. These results support homology of the amphioxus frontal eye and the vertebrate eyes and yield insights into their evolutionary origin.
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