1
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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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Mattern KMJ, Blancas-Velázquez AS, Ngo MT, Bille S, Hertz H, Bering T, Rath MF. The ISL LIM-homeobox 2 transcription factor is negatively regulated by circadian adrenergic signaling to repress the expression of Aanat in pinealocytes of the rat pineal gland. J Pineal Res 2023; 75:e12905. [PMID: 37649242 DOI: 10.1111/jpi.12905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/19/2023] [Accepted: 08/07/2023] [Indexed: 09/01/2023]
Abstract
Melatonin is synthesized in the pineal gland during nighttime in response to nocturnal increase in the activity of the enzyme aralkylamine N-acetyltransferase (AANAT), the transcription of which is modulated by several homeodomain transcription factors. Recent work suggests that the homeodomain transcription factor ISL LIM homeobox 2 (ISL2) is expressed in the pineal gland, but its role is currently unknown. With the purpose of identifying the mechanisms that control pineal expression of Isl2 and the possible function of Isl2 in circadian pineal biology, we report that Isl2 is specifically expressed in the pinealocytes of the rat pineal gland. Its expression exhibits a 24 h rhythm with high transcript and protein levels during the day and a trough in the second half of the night. This rhythm persists in darkness, and lesion studies reveal that it requires intact function of the suprachiasmatic nuclei, suggesting intrinsic circadian regulation. In vivo and in vitro experiments show that pineal Isl2 expression is repressed by adrenergic signaling acting via cyclic AMP; further, Isl2 is negatively regulated by the nocturnal transcription factor cone-rod homeobox. During development, pineal Isl2 expression is detectable from embryonic day 19, preceding Aanat by several days. In vitro knockdown of Isl2 is accompanied by an increase in Aanat transcript levels suggesting that ISL2 represses its daytime expression. Thus, rhythmic expression of ISL2 in pinealocytes is under the control of the suprachiasmatic nucleus acting via adrenergic signaling in the gland to repress nocturnal expression, while ISL2 itself negatively regulates daytime pineal expression of Aanat and thereby suggestively enhances the circadian rhythm in melatonin synthesis.
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Affiliation(s)
- Kuno M-J Mattern
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Aurea S Blancas-Velázquez
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikaella T Ngo
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Signe Bille
- 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
| | - Martin F Rath
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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3
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Hurst J, Attrodt G, Bartz-Schmidt KU, Mau-Holzmann UA, Spitzer MS, Schnichels S. A Case Study from the Past: "The RGC-5 vs. the 661W Cell Line: Similarities, Differences and Contradictions-Are They Really the Same?". Int J Mol Sci 2023; 24:13801. [PMID: 37762103 PMCID: PMC10531351 DOI: 10.3390/ijms241813801] [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] [Received: 05/08/2023] [Revised: 08/03/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023] Open
Abstract
In the pursuit of identifying the underlying pathways of ocular diseases, the use of cell lines such as (retinal ganglion cell-5) RGC-5 and 661W became a valuable tool, including pathologies like retinal degeneration and glaucoma. In 2001, the establishment of the RGC-5 cell line marked a significant breakthrough in glaucoma research. Over time, however, concerns arose about the true nature of RGC-5 cells, with conflicting findings in the literature regarding their identity as retinal ganglion cells or photoreceptor-like cells. This study aimed to address the controversy surrounding the RGC-5 cell line's origin and properties by comparing it with the 661W cell line, a known cone photoreceptor model. Both cell lines were differentiated according to two prior published redifferentiation protocols under the same conditions using 500 nM of trichostatin A (TSA) and investigated for their morphological and neuronal marker properties. The results demonstrated that both cell lines are murine, and they exhibited distinct morphological and neuronal marker properties. Notably, the RGC-5 cells showed higher expression of the neuronal marker β-III tubulin and increased Thy-1-mRNA compared with the 661W cells, providing evidence of their different properties. The findings emphasize the importance of verifying the authenticity of cell lines used in ocular research and highlight the risks of contamination and altered cell properties.
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Affiliation(s)
- José Hurst
- Center for Ophthalmology, University Eye Hospital Tübingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany (K.-U.B.-S.); (S.S.)
| | - Gesine Attrodt
- Center for Ophthalmology, University Eye Hospital Tübingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany (K.-U.B.-S.); (S.S.)
| | - Karl-Ulrich Bartz-Schmidt
- Center for Ophthalmology, University Eye Hospital Tübingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany (K.-U.B.-S.); (S.S.)
| | - Ulrike Angelika Mau-Holzmann
- Institute for Medical Genetics and Applied Genomics, Center for Rare Diseases, University of Tuebingen, Calwerstrasse 7, 72076 Tübingen, Germany
| | - Martin Stephan Spitzer
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf (UKE), Martinistraße 52, 20251 Hamburg, Germany;
| | - Sven Schnichels
- Center for Ophthalmology, University Eye Hospital Tübingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany (K.-U.B.-S.); (S.S.)
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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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OTX2 Non-Cell Autonomous Activity Regulates Inner Retinal Function. eNeuro 2020; 7:ENEURO.0012-19.2020. [PMID: 32737182 PMCID: PMC7477954 DOI: 10.1523/eneuro.0012-19.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/19/2020] [Accepted: 05/05/2020] [Indexed: 12/11/2022] Open
Abstract
OTX2 is a homeoprotein transcription factor expressed in photoreceptors and bipolar cells in the retina. OTX2, like many other homeoproteins, transfers between cells and exerts non-cell autonomous effects such as promoting the survival of retinal ganglion cells that do not express the protein. Here we used a genetic approach to target extracellular OTX2 in the retina by conditional expression of a secreted single-chain anti-OTX2 antibody. Compared with control mice, the expression of this antibody by parvalbumin-expressing neurons in the retina is followed by a reduction in visual acuity in 1-month-old mice with no alteration of the retinal structure or cell type number or aspect. The a-waves and b-waves measured by electroretinogram were also indistinguishable from those of control mice, suggesting no functional deficit of photoreceptors and bipolar cells. Mice expressing the OTX2-neutralizing antibody did show a significant doubling in the flicker amplitude and a reduction in oscillatory potential, consistent with a change in inner retinal function. Our results show that interfering in vivo with OTX2 non-cell autonomous activity in the postnatal retina leads to an alteration in inner retinal cell functions and causes a deficit in visual acuity.
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Her9/Hes4 is required for retinal photoreceptor development, maintenance, and survival. Sci Rep 2020; 10:11316. [PMID: 32647335 PMCID: PMC7347560 DOI: 10.1038/s41598-020-68172-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/11/2020] [Indexed: 11/13/2022] Open
Abstract
The intrinsic and extrinsic factors that regulate vertebrate photoreceptor specification and differentiation are complex, and our understanding of all the players is far from complete. Her9, the zebrafish ortholog of human HES4, is a basic helix-loop-helix-orange transcriptional repressor that regulates neurogenesis in several developmental contexts. We have previously shown that her9 is upregulated during chronic rod photoreceptor degeneration and regeneration in adult zebrafish, but little is known about the role of her9 during retinal development. To better understand the function of Her9 in the retina, we generated zebrafish her9 CRISPR mutants. Her9 homozygous mutants displayed striking retinal phenotypes, including decreased numbers of rods and red/green cones, whereas blue and UV cones were relatively unaffected. The reduction in rods and red/green cones correlated with defects in photoreceptor subtype lineage specification. The remaining rods and double cones displayed abnormal outer segments, and elevated levels of apoptosis. In addition to the photoreceptor defects, her9 mutants also possessed a reduced proliferative ciliary marginal zone, and decreased and disorganized Müller glia. Mutation of her9 was larval lethal, with no mutants surviving past 13 days post fertilization. Our results reveal a previously undescribed role for Her9/Hes4 in photoreceptor differentiation, maintenance, and survival.
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Wu Y, Qiu J, Chen S, Chen X, Zhang J, Zhuang J, Liu S, Yang M, Zhou P, Chen H, Ge J, Yu K, Zhuang J. Crx Is Posttranscriptionally Regulated by Light Stimulation in Postnatal Rat Retina. Front Cell Dev Biol 2020; 8:174. [PMID: 32318566 PMCID: PMC7154164 DOI: 10.3389/fcell.2020.00174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 03/02/2020] [Indexed: 11/13/2022] Open
Abstract
Cone rod homeobox (Crx) plays a key role at the center of a regulatory network that coordinates many pathways in the retina. Its abnormal expression induces retinal disorders. However, the underlying regulatory mechanism of Crx expression is not well defined. Here, we present data that show that the levels of Crx mRNA were inconsistent with that of Crx protein in primary retinal neurocytes cultured in light conditions. Crx protein levels were significantly higher (2.56-fold) in cells cultured in the dark than in cells cultured in light, whereas Crx mRNA was not changed in either type of cell. Moreover, the expression of Crx protein showed a significant light intensity-dependent decrease. Consistently, Crx downstream genes rhodopsin and arrestin also decreased in retinal neurocytes upon light exposure. Furthermore, Crx promoter activity assay performed in primary retinal neurocytes further indicated that light exposure and darkness did not affect its inducibility. In addition, the inconsistency between Crx mRNA and protein expression after light exposure was not observed in 661w cells transfected with plasmid pcDNA3.1-Crx, suggesting that the inconsistency between Crx mRNA and protein induced by light was specific to the endogenous Crx. More importantly, this observation was confirmed in vivo in postnatal day 15 (P15) retinas but not in adult retinas, further implicating that the posttranscriptional regulation mechanism may be involved in Crx expression in the developing retina. Therefore, our study sheds light on the mechanism of Crx expression in postnatal rat retina.
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Affiliation(s)
- Yihui Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jin Qiu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Shuilian Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xi Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jing Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jiejie Zhuang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Sian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Meng Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Pan Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Haoting Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jian Ge
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Keming Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jing Zhuang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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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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9
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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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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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Bering T, Carstensen MB, Wörtwein G, Weikop P, Rath MF. The Circadian Oscillator of the Cerebral Cortex: Molecular, Biochemical and Behavioral Effects of Deleting the Arntl Clock Gene in Cortical Neurons. Cereb Cortex 2018; 28:644-657. [PMID: 28052921 DOI: 10.1093/cercor/bhw406] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 12/20/2016] [Indexed: 11/13/2022] Open
Abstract
A molecular circadian oscillator resides in neurons of the cerebral cortex, but its role is unknown. Using the Cre-LoxP method, we have here abolished the core clock gene Arntl in those neurons. This mouse represents the first model carrying a deletion of a circadian clock component specifically in an extrahypothalamic cell type of the brain. Molecular analyses of clock gene expression in the cerebral cortex of the Arntl conditional knockout mouse revealed disrupted circadian expression profiles, whereas clock gene expression in the suprachiasmatic nucleus was still rhythmic, thus showing that Arntl is required for normal function of the cortical circadian oscillator. Daily rhythms in running activity and temperature were not influenced, whereas the resynchronization response to experimental jet-lag exhibited minor though significant differences between genotypes. The tail-suspension test revealed significantly prolonged immobility periods in the knockout mouse indicative of a depressive-like behavioral state. This phenotype was accompanied by reduced norepinephrine levels in the cerebral cortex. Our data show that Arntl is required for normal cortical clock function and further give reason to suspect that the circadian oscillator of the cerebral cortex is involved in regulating both circadian biology and mood-related behavior and biochemistry.
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Affiliation(s)
- Tenna Bering
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Laboratory of Neuropsychiatry, Psychiatric Center Copenhagen, Mental Health Services of the Capital Region of Denmark, DK-2100 Copenhagen, Denmark
| | - Mikkel Bloss Carstensen
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Gitta Wörtwein
- Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1014 Copenhagen, Denmark
| | - Pia Weikop
- Laboratory of Neuropsychiatry, Psychiatric Center Copenhagen, Mental Health Services of the Capital Region of Denmark, DK-2100 Copenhagen, Denmark
| | - Martin Fredensborg Rath
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
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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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Beltran WA, Cideciyan AV, Boye SE, Ye GJ, Iwabe S, Dufour VL, Marinho LF, Swider M, Kosyk MS, Sha J, Boye SL, Peterson JJ, Witherspoon CD, Alexander JJ, Ying GS, Shearman MS, Chulay JD, Hauswirth WW, Gamlin PD, Jacobson SG, Aguirre GD. Optimization of Retinal Gene Therapy for X-Linked Retinitis Pigmentosa Due to RPGR Mutations. Mol Ther 2017; 25:1866-1880. [PMID: 28566226 DOI: 10.1016/j.ymthe.2017.05.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 04/14/2017] [Accepted: 05/05/2017] [Indexed: 01/09/2023] Open
Abstract
X-linked retinitis pigmentosa (XLRP) caused by mutations in the RPGR gene is an early onset and severe cause of blindness. Successful proof-of-concept studies in a canine model have recently shown that development of a corrective gene therapy for RPGR-XLRP may now be an attainable goal. In preparation for a future clinical trial, we have here optimized the therapeutic AAV vector construct by showing that GRK1 (rather than IRBP) is a more efficient promoter for targeting gene expression to both rods and cones in non-human primates. Two transgenes were used in RPGR mutant (XLPRA2) dogs under the control of the GRK1 promoter. First was the previously developed stabilized human RPGR (hRPGRstb). Second was a new full-length stabilized and codon-optimized human RPGR (hRPGRco). Long-term (>2 years) studies with an AAV2/5 vector carrying hRPGRstb under control of the GRK1 promoter showed rescue of rods and cones from degeneration and retention of vision. Shorter term (3 months) studies demonstrated comparable preservation of photoreceptors in canine eyes treated with an AAV2/5 vector carrying either transgene under the control of the GRK1 promoter. These results provide the critical molecular components (GRK1 promoter, hRPGRco transgene) to now construct a therapeutic viral vector optimized for RPGR-XLRP patients.
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Affiliation(s)
- William A Beltran
- Division of Experimental Retinal Therapies, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19014, USA.
| | - Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shannon E Boye
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Guo-Jie Ye
- Applied Genetic Technologies Corporation, Alachua, FL 32615, USA
| | - Simone Iwabe
- Division of Experimental Retinal Therapies, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19014, USA
| | - Valerie L Dufour
- Division of Experimental Retinal Therapies, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19014, USA
| | - Luis Felipe Marinho
- Division of Experimental Retinal Therapies, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19014, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mychajlo S Kosyk
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jin Sha
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sanford L Boye
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - James J Peterson
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - C Douglas Witherspoon
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - John J Alexander
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA 30303, USA
| | - Gui-Shuang Ying
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mark S Shearman
- Applied Genetic Technologies Corporation, Alachua, FL 32615, USA
| | - Jeffrey D Chulay
- Applied Genetic Technologies Corporation, Alachua, FL 32615, USA
| | - William W Hauswirth
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Paul D Gamlin
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19014, USA
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14
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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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15
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Zhang SJ, Li YF, Tan RR, Tsoi B, Huang WS, Huang YH, Tang XL, Hu D, Yao N, Yang X, Kurihara H, Wang Q, He RR. A new gestational diabetes mellitus model: hyperglycemia-induced eye malformation via inhibition of Pax6 in the chick embryo. Dis Model Mech 2016; 9:177-86. [PMID: 26744353 PMCID: PMC4770145 DOI: 10.1242/dmm.022012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 12/26/2015] [Indexed: 12/23/2022] Open
Abstract
Gestational diabetes mellitus (GDM) is one of the leading causes of fetal malformations. However, few models have been developed to study the underlying mechanisms of GDM-induced fetal eye malformation. In this study, a high concentration of glucose (0.2 mmol per egg) was injected into the air sac of chick embryos on embryo development day (EDD) 1 to develop a hyperglycemia model. Results showed that 47.3% of embryonic eye malformation happened on EDD 5. In this model, the key genes regulating eye development, Pax6, Six3 and Otx2, were downregulated by hyperglycemia. Among these genes, the expression of Pax6 was the most vulnerable to hyperglycemia, being suppressed by 70%. A reduction in Pax6 gene expression induced eye malformation in chick embryos. However, increased expression of Pax6 in chick embryos could rescue hyperglycemia-induced eye malformation. Hyperglycemia stimulated O-linked N-acetylglucosaminylation, which caused oxidative stress in chick embryos. Pax6 was found to be vulnerable to free radicals, but the antioxidant edaravone could restore Pax6 expression and reverse eye malformation. These results illustrated a successful establishment of a new chick embryo model to study the molecular mechanism of hyperglycemia-induced eye malformation. The suppression of the Pax6 gene is probably mediated by oxidative stress and could be a crucial target for the therapy of GDM-induced embryonic eye malformation. Summary: Hyperglycemia inhibited Pax6 via oxidative stress and impaired eye development in the chick embryo, a new gestational diabetes mellitus model.
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Affiliation(s)
- Shi-Jie Zhang
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Yi-Fang Li
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Rui-Rong Tan
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Bun Tsoi
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Wen-Shan Huang
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Yi-Hua Huang
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Xiao-Long Tang
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Dan Hu
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Nan Yao
- Guangdong Research Institute of Traditional Chinese Medicine Manufacturing Technology, Guangzhou 510095, China
| | - Xuesong Yang
- Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632, China
| | - Hiroshi Kurihara
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Qi Wang
- Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Rong-Rong He
- Anti-stress and Health Research Center, College of Pharmacy, Jinan University, Guangzhou 510632, China
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16
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Tan RR, Zhang SJ, Li YF, Tsoi B, Huang WS, Yao N, Hong M, Zhai YJ, Mao ZF, Tang LP, Kurihara H, Wang Q, He RR. Proanthocyanidins Prevent High Glucose-Induced Eye Malformation by Restoring Pax6 Expression in Chick Embryo. Nutrients 2015; 7:6567-81. [PMID: 26262640 PMCID: PMC4555138 DOI: 10.3390/nu7085299] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 07/24/2015] [Indexed: 12/16/2022] Open
Abstract
Gestational diabetes mellitus (GDM) is one of the leading causes of offspring malformations, in which eye malformation is an important disease. It has raised demand for therapy to improve fetal outcomes. In this study, we used chick embryo to establish a GDM model to study the protective effects of proanthocyanidins on eye development. Chick embryos were exposed to high glucose (0.2 mmol/egg) on embryo development day (EDD) 1. Proanthocyanidins (1 and 10 nmol/egg) were injected into the air sac on EDD 0. Results showed that both dosages of proanthocyanidins could prevent the eye malformation and rescue the high glucose-induced oxidative stress significantly, which the similar effects were showed in edaravone. However, proanthocyanidins could not decrease the glucose concentration of embryo eye. Moreover, the key genes regulating eye development, Pax6, was down-regulated by high glucose. Proanthocyanidins could restore the suppressed expression of Pax6. These results indicated proanthocyanidins might be a promising natural agent to prevent high glucose-induced eye malformation by restoring Pax6 expression.
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Affiliation(s)
- Rui-Rong Tan
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
| | - Shi-Jie Zhang
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
- Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Yi-Fang Li
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
| | - Bun Tsoi
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
| | - Wen-Shan Huang
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
| | - Nan Yao
- Guangdong Research Institute of Traditional Chinese Medicine Manufacturing Technology, Guangzhou 510095, Guangdong, China.
| | - Mo Hong
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
| | - Yu-Jia Zhai
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
| | - Zhong-Fu Mao
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
| | - Lu-Ping Tang
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
| | - Hiroshi Kurihara
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
| | - Qi Wang
- Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Rong-Rong He
- Anti-stress and Health Center, Pharmacy College, Jinan University, Guangzhou 510632, China.
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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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Photic stimulation of the suprachiasmatic nucleus via the non-visual optic system. A gene expression study in the blind Crx −/− mouse. Cell Tissue Res 2014; 358:239-48. [DOI: 10.1007/s00441-014-1910-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/23/2014] [Indexed: 12/23/2022]
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19
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Rath MF, Rovsing L, Møller M. Circadian oscillators in the mouse brain: molecular clock components in the neocortex and cerebellar cortex. Cell Tissue Res 2014; 357:743-55. [PMID: 24842045 DOI: 10.1007/s00441-014-1878-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/25/2014] [Indexed: 01/27/2023]
Abstract
The circadian timekeeper of the mammalian brain resides in the suprachiasmatic nucleus of the hypothalamus (SCN), and is characterized by rhythmic expression of a set of clock genes with specific 24-h daily profiles. An increasing amount of data suggests that additional circadian oscillators residing outside the SCN have the capacity to generate peripheral circadian rhythms. We have recently shown the presence of SCN-controlled oscillators in the neocortex and cerebellum of the rat. The function of these peripheral brain clocks is unknown, and elucidating this could involve mice with conditional cell-specific clock gene deletions. This prompted us to analyze the molecular clockwork of the mouse neocortex and cerebellum in detail. Here, by use of in situ hybridization and quantitative RT-PCR, we show that clock genes are expressed in all six layers of the neocortex and the Purkinje and granular cell layers of the cerebellar cortex of the mouse brain. Among these, Per1, Per2, Cry1, Arntl, and Nr1d1 exhibit circadian rhythms suggesting that local running circadian oscillators reside within neurons of the mouse neocortex and cerebellar cortex. The temporal expression profiles of clock genes are similar in the neocortex and cerebellum, but they are delayed by 5 h as compared to the SCN, suggestively reflecting a master-slave relationship between the SCN and extra-hypothalamic oscillators. Furthermore, ARNTL protein products are detectable in neurons of the mouse neocortex and cerebellum, as revealed by immunohistochemistry. These findings give reason to further pursue the physiological significance of circadian oscillators in the mouse neocortex and cerebellum.
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Affiliation(s)
- Martin F Rath
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Rigshospitalet 6102, Blegdamsvej 9, Copenhagen, DK-2100, Denmark,
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20
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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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21
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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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22
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Choroid-plexus-derived Otx2 homeoprotein constrains adult cortical plasticity. Cell Rep 2013; 3:1815-23. [PMID: 23770240 DOI: 10.1016/j.celrep.2013.05.014] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 03/26/2013] [Accepted: 05/09/2013] [Indexed: 01/27/2023] Open
Abstract
Brain plasticity is often restricted to critical periods in early life. Here, we show that a key regulator of this process in the visual cortex, Otx2 homeoprotein, is synthesized and secreted globally from the choroid plexus. Consequently, Otx2 is maintained in selected GABA cells unexpectedly throughout the mature forebrain. Genetic disruption of choroid-expressed Otx2 impacts these distant circuits and in the primary visual cortex reopens binocular plasticity to restore vision in amblyopic mice. The potential to regulate adult cortical plasticity through the choroid plexus underscores the importance of this structure in brain physiology and offers therapeutic approaches to recovery from a broad range of neurodevelopmental disorders.
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23
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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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24
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Schang AL, Bleux C, Chenut MC, Ngô-Muller V, Quérat B, Jeanny JC, Counis R, Cohen-Tannoudji J, Laverrière JN. Identification and analysis of two novel sites of rat GnRH receptor gene promoter activity: the pineal gland and retina. Neuroendocrinology 2013; 97:115-31. [PMID: 22414758 DOI: 10.1159/000337661] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 02/28/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND AIMS In mammals, activation of pituitary GnRH receptor (GnRHR) by hypothalamic GnRH increases the synthesis and secretion of LH and FSH, which, in turn, regulate gonadal functions. However, GnRHR gene (Gnrhr) expression is not restricted to the pituitary. METHODS To gain insight into the extrapituitary expression of Gnrhr, a transgenic mouse model that expresses the human placental alkaline phosphatase reporter gene driven by the rat Gnrhr promoter was created. RESULTS This study shows that the rat Gnrhr promoter is operative in two functionally related organs, the pineal gland, as early as embryonic day (E) 13.5, and the retina where activity was only detected at E17.5. Accordingly, Gnrhr mRNA were present in both tissues. Transcription factors known to regulate Gnrhr promoter activity such as the LIM homeodomain factors LHX3 and ISL1 were also detected in the retina. Furthermore, transient transfection studies in CHO and gonadotrope cells revealed that OTX2, a major transcription factor in both pineal and retina cell differentiation, is able to activate the Gnrhr promoter together with either CREB or PROP1, depending on the cell context. CONCLUSION Rather than using alternate promoters, Gnrhr expression is directed to diverse cell lineages through specific associations of transcription factors acting on distinct response elements along the same promoter. These data open new avenues regarding GnRH-mediated control of seasonal and circadian rhythms in reproductive physiology.
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Affiliation(s)
- Anne-Laure Schang
- Université Paris Diderot Paris 7, Sorbonne Paris Cité, Biologie Fonctionnelle et Adaptative, EAC CNRS 4413, Physiologie de l'Axe Gonadotrope, Paris, France
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Kaalund SS, Riise J, Broberg BV, Fabricius K, Karlsen AS, Secher T, Plath N, Pakkenberg B. Differential expression of parvalbumin in neonatal phencyclidine-treated rats and socially isolated rats. J Neurochem 2012; 124:548-57. [PMID: 23083323 DOI: 10.1111/jnc.12061] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 10/02/2012] [Accepted: 10/02/2012] [Indexed: 12/11/2022]
Abstract
Decreased parvalbumin expression is a hallmark of the pathophysiology of schizophrenia and has been associated with abnormal cognitive processing and decreased network specificity. It is not known whether this decrease is due to reduced expression of the parvalbumin protein or degeneration of parvalbumin-positive interneurons (PV(+) interneurons). In this study, we examined PV(+) expression in two rat models of cognitive dysfunction in schizophrenia: the environmental social isolation (SI) and pharmacological neonatal phencyclidine (neoPCP) models. Using a stereological method, the optical fractionator, we counted neurons, PV(+) interneurons, and glial cells in the medial prefrontal cortex (mPFC) and hippocampus (HPC). In addition, we quantified the mRNA level of parvalbumin in the mPFC. There was a statistically significant reduction in the number of PV(+) interneurons (p = 0.021) and glial cells (p = 0.024) in the mPFC of neonatal phencyclidine rats, but not in SI rats. We observed no alterations in the total number of neurons, hippocampal PV(+) interneurons, parvalbumin mRNA expression or volume of the mPFC or HPC in the two models. Thus, as the total number of neurons remains unchanged following phencyclidine (PCP) treatment, we suggest that the decreased number of counted PV(+) interneurons represents a reduced parvalbumin protein expression below immunohistochemical detection limit rather than a true cell loss. Furthermore, these results indicate that the effect of neonatal PCP treatment is not limited to neuronal populations.
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Affiliation(s)
- Sanne S Kaalund
- Research Laboratory for Stereology and Neuroscience, Bispebjerg University Hospital, Copenhagen, Denmark
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26
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Abstract
Long noncoding RNAs (lncRNAs) play a broad range of biological roles, including regulation of expression of genes and chromosomes. Here, we present evidence that lncRNAs are involved in vertebrate circadian biology. Differential night/day expression of 112 lncRNAs (0.3 to >50 kb) occurs in the rat pineal gland, which is the source of melatonin, the hormone of the night. Approximately one-half of these changes reflect nocturnal increases. Studies of eight lncRNAs with 2- to >100-fold daily rhythms indicate that, in most cases, the change results from neural stimulation from the central circadian oscillator in the suprachiasmatic nucleus (doubling time = 0.5-1.3 h). Light exposure at night rapidly reverses (halving time = 9-32 min) levels of some of these lncRNAs. Organ culture studies indicate that expression of these lncRNAs is regulated by norepinephrine acting through cAMP. These findings point to a dynamic role of lncRNAs in the circadian system.
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Clokie SJH, Lau P, Kim HH, Coon SL, Klein DC. MicroRNAs in the pineal gland: miR-483 regulates melatonin synthesis by targeting arylalkylamine N-acetyltransferase. J Biol Chem 2012; 287:25312-24. [PMID: 22908386 PMCID: PMC3408182 DOI: 10.1074/jbc.m112.356733] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/14/2012] [Indexed: 11/06/2022] Open
Abstract
MicroRNAs (miRNAs) play a broad range of roles in biological regulation. In this study, rat pineal miRNAs were profiled for the first time, and their importance was evaluated by focusing on the main function of the pineal gland, melatonin synthesis. Massively parallel sequencing and related methods revealed the miRNA population is dominated by a small group of miRNAs as follows: ~75% is accounted for by 15 miRNAs; miR-182 represents 28%. In addition to miR-182, miR-183 and miR-96 are also highly enriched in the pineal gland, a distinctive pattern also found in the retina. This effort also identified previously unrecognized miRNAs and other small noncoding RNAs. Pineal miRNAs do not exhibit a marked night/day difference in abundance with few exceptions (e.g. 2-fold night/day differences in the abundance of miR-96 and miR-182); this contrasts sharply with the dynamic 24-h pattern that characterizes the pineal transcriptome. During development, the abundance of most pineal gland-enriched miRNAs increases; however, there is a marked decrease in at least one, miR-483. miR-483 is a likely regulator of melatonin synthesis, based on the following. It inhibits melatonin synthesis by pinealocytes in culture; it acts via predicted binding sites in the 3"-UTR of arylalkylamine N-acetyltransferase (Aanat) mRNA, the penultimate enzyme in melatonin synthesis, and it exhibits a developmental profile opposite to that of Aanat transcripts. Additionally, a miR-483 targeted antagonist increased melatonin synthesis in neonatal pinealocytes. These observations support the hypothesis that miR-483 suppresses Aanat mRNA levels during development and that the developmental decrease in miR-483 abundance promotes melatonin synthesis.
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Affiliation(s)
- Samuel J. H. Clokie
- From the Section on Neuroendocrinology, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Pierre Lau
- the Center for Human Genetics and Leuven Institute for Neurodegenerative Disorders (LIND), University of Leuven, 3000 Leuven, Belgium
| | - Hyun Hee Kim
- From the Section on Neuroendocrinology, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Steven L. Coon
- From the Section on Neuroendocrinology, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892 and
| | - David C. Klein
- From the Section on Neuroendocrinology, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892 and
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Rath MF, Rohde K, Fahrenkrug J, Møller M. Circadian clock components in the rat neocortex: daily dynamics, localization and regulation. Brain Struct Funct 2012; 218:551-62. [DOI: 10.1007/s00429-012-0415-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 04/03/2012] [Indexed: 12/13/2022]
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Rovsing L, Clokie S, Bustos DM, Rohde K, Coon SL, Litman T, Rath MF, Møller M, Klein DC. Crx broadly modulates the pineal transcriptome. J Neurochem 2011; 119:262-74. [PMID: 21797868 DOI: 10.1111/j.1471-4159.2011.07405.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cone-rod homeobox (Crx) encodes Crx, a transcription factor expressed selectively in retinal photoreceptors and pinealocytes, the major cell type of the pineal gland. In this study, the influence of Crx on the mammalian pineal gland was studied by light and electron microscopy and by use of microarray and qRTPCR technology, thereby extending previous studies on selected genes (Furukawa et al. 1999). Deletion of Crx was not found to alter pineal morphology, but was found to broadly modulate the mouse pineal transcriptome, characterized by a>2-fold down-regulation of 543 genes and a>2-fold up-regulation of 745 genes (p<0.05). Of these, one of the most highly up-regulated (18-fold) was Hoxc4, a member of the Hox gene family, members of which are known to control gene expression cascades. During a 24-h period, a set of 51 genes exhibited differential day/night expression in pineal glands of wild-type animals; only eight of these were also day/night expressed in the Crx⁻/⁻ pineal gland. However, in the Crx⁻/⁻ pineal gland 41 genes exhibited differential night/day expression that was not seen in wild-type animals. These findings indicate that Crx broadly modulates the pineal transcriptome and also influences differential night/day gene expression in this tissue. Some effects of Crx deletion on the pineal transcriptome might be mediated by Hoxc4 up-regulation.
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Affiliation(s)
- Louise Rovsing
- Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark
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30
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Rohde K, Klein DC, Møller M, Rath MF. Rax : developmental and daily expression patterns in the rat pineal gland and retina. J Neurochem 2011; 118:999-1007. [PMID: 21749377 DOI: 10.1111/j.1471-4159.2011.07385.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Retina and anterior neural fold homeobox (Rax) gene encodes a transcription factor essential for vertebrate eye development. Recent microarray studies indicate that Rax is expressed in the adult rat pineal gland and retina. The present study reveals that Rax expression levels in the rat change significantly during retinal development with a peak occurring at embryonic day 18, whereas Rax expression in the pineal is relatively delayed and not detectable until embryonic day 20. In both tissues, Rax is expressed throughout postnatal development into adulthood. In the mature rat pineal gland, the abundance of Rax transcripts increases 2-fold during the light period with a peak occurring at dusk. These findings are consistent with the evidence that Rax is of functional importance in eye development and suggest a role of Rax in the developing pineal gland. In addition, it would appear possible that Rax contributes to phenotype maintenance in the mature retina and pineal gland and may facilitate 24-h changes in the pineal transcriptome.
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Affiliation(s)
- Kristian Rohde
- Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark
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31
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Otx2 promotes the survival of damaged adult retinal ganglion cells and protects against excitotoxic loss of visual acuity in vivo. J Neurosci 2011; 31:5495-503. [PMID: 21471386 DOI: 10.1523/jneurosci.0187-11.2011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Retinal ganglion cells (RGCs) are the projection neurons from the eye to the brain and their loss results in visual impairment in a number of diseases. Transcription factors with a homeodomain can translocate between cells and, in at least one reported case, can stimulate neuronal survival. Otx2 is a homeoprotein transcription factor expressed in the retina that is taken up by RGCs. We thus hypothesized that Otx2 capture could regulate the survival of adult RGCs. We report that Otx2 stimulates the survival of adult mouse and rat RGCs in vitro and protects RGCs against NMDA-induced toxicity in vivo in mice. In the latter model, Otx2 also preserves visual acuity.
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32
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Moos T, Bernth N, Courtois Y, Morgan EH. Developmental iron uptake and axonal transport in the retina of the rat. Mol Cell Neurosci 2011; 46:607-13. [PMID: 21211566 DOI: 10.1016/j.mcn.2010.12.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 12/24/2010] [Accepted: 12/27/2010] [Indexed: 10/18/2022] Open
Abstract
We examined differently aged postnatal (P) rats for the distribution and uptake of iron in the eye with the main emphasis on iron uptake in the retina. The concentration of iron in the eye was 48 μg/g in rats aged one postnatal day (P1). Then concentration fell to approximately 12 μg/g at P30 and rose to 35 μg/g at P70. Perls' stain which labels both ferrous and ferric iron was found to exhibit a weak labeling in the retina at P1 contrasted by a robust labeling of macrophages found in the choroid of the retina. In older aged rats, the labeling of cells of the retina was much more intense and confined to cells widespread in the layers of the retina. In both P16 and adult rats injected intravenously with [(59)Fe-(125)I]transferrin, the uptake of (59)Fe, estimated as the volume of distribution, was significantly higher than that of [(125)I]transferrin, and uptake of both compounds was higher than that of simultaneously injected [(131)I]albumin. In the P16 rat, the uptake of (59)Fe expressed as the volume of distribution, V(D), rose linearly reaching approximately 2500 nl at 60 min. In the adult rat, the uptake of (59)Fe was of the same magnitude. Comparing P1 and P16 rats, the uptake of (59)Fe, [(125)I]transferrin and [(131)I]albumin was higher at P1 in both eyeball and retina. Emulsion autoradiography of retinas from P16 and adult rats injected with [(55)Fe]transferrin into the vitreous body showed uptake mainly in photoreceptor cells and retinal ganglion cells. Adult rats injected into the vitreous body with [(59)Fe]transferrin showed anterograde axonal transport from the retina into the optic nerve, optic tract, and superior colliculus. Immunoprecipitates of homogenates of the optic nerve revealed that (59)Fe was precipitable with an antibody raised against ferritin, indicative of detachment of iron from transferrin within the axons of the retinal ganglion cells. The data demonstrate an age-dependent but continuous iron uptake by the retina, and are indicative of anterograde axonal transport of transferrin by retinal ganglion cells.
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Affiliation(s)
- T Moos
- Section of Neurobiology, Biomedicine, Aalborg University, Denmark.
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33
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Rovsing L, Rath MF, Lund-Andersen C, Klein DC, Møller M. A neuroanatomical and physiological study of the non-image forming visual system of the cone-rod homeobox gene (Crx) knock out mouse. Brain Res 2010; 1343:54-65. [PMID: 20438719 DOI: 10.1016/j.brainres.2010.04.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 04/13/2010] [Accepted: 04/14/2010] [Indexed: 11/18/2022]
Abstract
The anatomy and physiology of the non-image forming visual system was investigated in a visually blind cone-rod homeobox gene (Crx) knock-out mouse (Crx(-)(/)(-)), which lacks the outer segments of the photoreceptors. We show that the suprachiasmatic nuclei (SCN) in the Crx(-/-) mouse exhibit morphology as in the wild type mouse. In addition, the SCN contain vasoactive intestinal peptide-, vasopressin-, and gastrin-releasing peptide-immunoreactive neurons as present in the wild type. Anterograde in vivo tracings from the retina of the Crx(-/-) and wild type mouse showed that the retinohypothalamic projection to the SCN and the central optic pathways were similar in both animals. Telemetric monitoring of the running activity and temperature revealed that both the Crx(-/-)and wild type mouse exhibited diurnal rhythms with a 24-h period, which could be phase changed by light. However, power spectral analysis revealed that both rhythms in the Crx(-/-) mouse were less robust than those in the wild type. The normal development of the SCN and the central visual pathways in the Crx(-/-) mouse suggests that a modulatory input from the photoreceptors in the peripheral retina to the retinal melanopsin neurons or the SCN may be necessary for a normal function of the non-image forming system of the mouse. However, a change in the SCN of the Crx(-/-) mouse might also explain the observed circadian differences between the knock out mouse and wild type mouse.
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Affiliation(s)
- Louise Rovsing
- Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark
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Larsen KB, Lutterodt MC, Møllgård K, Møller M. Expression of the homeobox genes OTX2 and OTX1 in the early developing human brain. J Histochem Cytochem 2010; 58:669-78. [PMID: 20354145 DOI: 10.1369/jhc.2010.955757] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In rodents, the Otx2 gene is expressed in the diencephalon, mesencephalon, and cerebellum and is crucial for the development of these brain regions. Together with Otx1, Otx2 is known to cooperate with other genes to develop the caudal forebrain and, further, Otx1 is also involved in differentiation of young neurons of the deeper cortical layers. We have studied the spatial and temporal expression of the two homeobox genes OTX2 and OTX1 in human fetal brains from 7 to 14 weeks postconception by in situ hybridization and immunohistochemistry. OTX2 was expressed in the diencephalon, mesencephalon, and choroid plexus, with a minor expression in the basal telencephalon. The expression of OTX2 in the hippocampal anlage was strong, with no expression in the adjacent neocortex. Contrarily, the OTX1 expression was predominantly located in the proliferative zones of the neocortex. At later stages, the OTX2 protein was found in the subcommissural organ, pineal gland, and cerebellum. The early expression of OTX2 and OTX1 in proliferative cell layers of the human fetal brain supports the concept that these homeobox genes are important in neuronal cell development and differentiation: OTX1 primarily in the neocortex, and OTX2 in the archicortex, diencephalon, rostral brain stem, and cerebellum.
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Affiliation(s)
- Karen B Larsen
- Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark.
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Vopalensky P, Kozmik Z. Eye evolution: common use and independent recruitment of genetic components. Philos Trans R Soc Lond B Biol Sci 2009; 364:2819-32. [PMID: 19720647 DOI: 10.1098/rstb.2009.0079] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Animal eyes can vary in complexity ranging from a single photoreceptor cell shaded by a pigment cell to elaborate arrays of these basic units, which allow image formation in compound eyes of insects or camera-type eyes of vertebrates. The evolution of the eye requires involvement of several distinct components-photoreceptors, screening pigment and genes orchestrating their proper temporal and spatial organization. Analysis of particular genetic and biochemical components shows that many evolutionary processes have participated in eye evolution. Multiple examples of co-option of crystallins, Galpha protein subunits and screening pigments contrast with the conserved role of opsins and a set of transcription factors governing eye development in distantly related animal phyla. The direct regulation of essential photoreceptor genes by these factors suggests that this regulatory relationship might have been already established in the ancestral photoreceptor cell.
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Affiliation(s)
- Pavel Vopalensky
- Department of Transcriptional Regulation, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 CZ 14220, Czech Republic
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Santagata S, Maire CL, Idbaih A, Geffers L, Correll M, Holton K, Quackenbush J, Ligon KL. CRX is a diagnostic marker of retinal and pineal lineage tumors. PLoS One 2009; 4:e7932. [PMID: 19936203 PMCID: PMC2775954 DOI: 10.1371/journal.pone.0007932] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 10/05/2009] [Indexed: 11/19/2022] Open
Abstract
Background CRX is a homeobox transcription factor whose expression and function is critical to maintain retinal and pineal lineage cells and their progenitors. To determine the biologic and diagnostic potential of CRX in human tumors of the retina and pineal, we examined its expression in multiple settings. Methodology/Principal Findings Using situ hybridization and immunohistochemistry we show that Crx RNA and protein expression are exquisitely lineage restricted to retinal and pineal cells during normal mouse and human development. Gene expression profiling analysis of a wide range of human cancers and cancer cell lines also supports that CRX RNA is highly lineage restricted in cancer. Immunohistochemical analysis of 22 retinoblastomas and 13 pineal parenchymal tumors demonstrated strong expression of CRX in over 95% of these tumors. Importantly, CRX was not detected in the majority of tumors considered in the differential diagnosis of pineal region tumors (n = 78). The notable exception was medulloblastoma, 40% of which exhibited CRX expression in a heterogeneous pattern readily distinguished from that seen in retino-pineal tumors. Conclusions/Significance These findings describe new potential roles for CRX in human cancers and highlight the general utility of lineage restricted transcription factors in cancer biology. They also identify CRX as a sensitive and specific clinical marker and a potential lineage dependent therapeutic target in retinoblastoma and pineoblastoma.
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Affiliation(s)
- Sandro Santagata
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
- Department of Pathology, Children's Hospital Boston, Boston, Massachusetts, United States of America
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Cecile L. Maire
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Medical Oncology and Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Ahmed Idbaih
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Medical Oncology and Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Lars Geffers
- Department of Genes and Behavior, Max-Planck-Institute of Biophysical Chemistry, Goettingen, Germany
| | - Mick Correll
- Center for Cancer Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Kristina Holton
- Center for Cancer Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - John Quackenbush
- Center for Cancer Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Keith L. Ligon
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
- Department of Pathology, Children's Hospital Boston, Boston, Massachusetts, United States of America
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Medical Oncology and Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- * E-mail:
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Rapicavoli NA, Blackshaw S. New meaning in the message: Noncoding RNAs and their role in retinal development. Dev Dyn 2009; 238:2103-14. [DOI: 10.1002/dvdy.21844] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Kim JS, Coon SL, Weller JL, Blackshaw S, Rath MF, Møller M, Klein DC. Muscleblind-like 2: circadian expression in the mammalian pineal gland is controlled by an adrenergic-cAMP mechanism. J Neurochem 2009; 110:756-64. [PMID: 19457059 DOI: 10.1111/j.1471-4159.2009.06184.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Muscleblind-like 2 (Mbnl2) is a zinc finger protein first identified in Drosophila. It appears to be essential for photoreceptor development and to be involved in RNA splicing. Here we report that Mbnl2 is strongly expressed in the rat pineal gland. The abundance of pineal Mbnl2 transcripts follows a marked circadian rhythm with peak levels approximately sevenfold higher at night than day levels. Mbnl2 protein exhibits a similar rhythm. In vitro studies indicate that the abundance of Mbnl2 transcripts and protein are controlled by an adrenergic/cAMP mechanism.
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Affiliation(s)
- Jong-So Kim
- Program on Developmental Endocrinology and Genetics, Section on Neuroendocrinology, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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Larsen KB, Lutterodt M, Rath MF, Møller M. Expression of the homeobox genes
PAX6
,
OTX2
, and
OTX1
in the early human fetal retina. Int J Dev Neurosci 2009; 27:485-92. [DOI: 10.1016/j.ijdevneu.2009.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 04/07/2009] [Accepted: 04/27/2009] [Indexed: 11/30/2022] Open
Affiliation(s)
- Karen B. Larsen
- Department of Neuroscience and Pharmacology, Faculty of Health SciencesUniversity of CopenhagenDenmark
| | - Melissa Lutterodt
- Laboratory of Biology and ReproductionRigshospitaletDenmark
- Department of Gynecology and ObstetricsFrederiksberg HospitalCopenhagenDenmark
| | - Martin F. Rath
- Department of Neuroscience and Pharmacology, Faculty of Health SciencesUniversity of CopenhagenDenmark
| | - Morten Møller
- Department of Neuroscience and Pharmacology, Faculty of Health SciencesUniversity of CopenhagenDenmark
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Sugiyama S, Prochiantz A, Hensch TK. From brain formation to plasticity: insights on Otx2 homeoprotein. Dev Growth Differ 2009; 51:369-77. [PMID: 19298552 DOI: 10.1111/j.1440-169x.2009.01093.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The shaping of neuronal circuits is essential during postnatal brain development. A window of neuronal remodeling by sensory experience typically occurs during a unique time in early life. The many types of behavior and perception, like human language, birdsong, hearing and vision are refined by experience during these distinct 'critical periods'. The onset of critical periods for vision is delayed in animals that remain in complete darkness from birth. It is then predicted that a 'messenger' within the visual pathway signals the amount of sensory experience that has occurred. Our recent results indicate that Otx2 homeoprotein, an essential morphogen for embryonic head formation, is reused later in life as this 'messenger' for critical period plasticity. The homeoprotein is stimulated by visual experience to propagate into the visual cortex, where it is internalized by GABAergic interneurons, especially Parvalbumin-positive cells (PV-cells). Otx2 promotes the maturation of PV-cells, consequently activating critical period onset in the visual cortex. Here, we discuss recent data that are beginning to illuminate the physiological function of non-cell autonomous homeoproteins, as well as the restriction of their transfer to PV-cells in vivo.
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Affiliation(s)
- Sayaka Sugiyama
- Department of Neurology, FM Kirby Neurobiology Center, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
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Rath MF, Bailey MJ, Kim JS, Ho AK, Gaildrat P, Coon SL, Møller M, Klein DC. Developmental and diurnal dynamics of Pax4 expression in the mammalian pineal gland: nocturnal down-regulation is mediated by adrenergic-cyclic adenosine 3',5'-monophosphate signaling. Endocrinology 2009; 150:803-11. [PMID: 18818287 PMCID: PMC2646524 DOI: 10.1210/en.2008-0882] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pax4 is a homeobox gene that is known to be involved in embryonic development of the endocrine pancreas. In this tissue, Pax4 counters the effects of the related protein, Pax6. Pax6 is essential for development of the pineal gland. In this study we report that Pax4 is strongly expressed in the pineal gland and retina of the rat. Pineal Pax4 transcripts are low in the fetus and increase postnatally; Pax6 exhibits an inverse pattern of expression, being more strongly expressed in the fetus. In the adult the abundance of Pax4 mRNA exhibits a diurnal rhythm in the pineal gland with maximal levels occurring late during the light period. Sympathetic denervation of the pineal gland by superior cervical ganglionectomy prevents the nocturnal decrease in pineal Pax4 mRNA. At night the pineal gland is adrenergically stimulated by release of norepinephrine from the sympathetic innervation; here, we found that treatment with adrenergic agonists suppresses pineal Pax4 expression in vivo and in vitro. This suppression appears to be mediated by cAMP, a second messenger of norepinephrine in the pineal gland, based on the observation that treatment with a cAMP mimic reduces pineal Pax4 mRNA levels. These findings suggest that the nocturnal decrease in pineal Pax4 mRNA is controlled by the sympathetic neural pathway that controls pineal function acting via an adrenergic-cAMP mechanism. The daily changes in Pax4 expression may influence gene expression in the pineal gland.
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Affiliation(s)
- Martin F Rath
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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Rath MF, Bailey MJ, Kim JS, Coon SL, Klein DC, Møller M. Developmental and daily expression of the Pax4 and Pax6 homeobox genes in the rat retina: localization of Pax4 in photoreceptor cells. J Neurochem 2008; 108:285-94. [PMID: 19012751 DOI: 10.1111/j.1471-4159.2008.05765.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pax4 is a homeobox gene encoding Pax4, a transcription factor that is essential for embryonic development of the endocrine pancreas. In the pancreas, Pax4 counters the effects of the related transcription factor, Pax6, which is known to be essential for eye morphogenesis. In this study, we have discovered that Pax4 is strongly expressed in retinal photoreceptors of the rat. Pax4 expression is not detectable in the foetal eye; however, postnatal Pax4 transcript levels rapidly increase. In contrast, Pax6 exhibits an inverse developmental pattern of expression being more strongly expressed in the foetal eye. Histological analysis revealed that Pax4 mRNA is exclusively expressed in the retinal photoreceptors, whereas Pax6 mRNA and protein are present in the inner nuclear layer and in the ganglion cell layer of the mature retina. In the adult retina, Pax4 transcripts exhibit a diurnal rhythm with maximal levels occurring during the light period, whereas retinal Pax6 transcript levels do not change throughout the day. The daily changes in Pax4 expression may contribute to daily changes in function in the differentiated retinal photoreceptor.
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Affiliation(s)
- Martin F Rath
- Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Copenhagen, Denmark.
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Langmann T, Lai CCL, Weigelt K, Tam BM, Warneke-Wittstock R, Moritz OL, Weber BHF. CRX controls retinal expression of the X-linked juvenile retinoschisis (RS1) gene. Nucleic Acids Res 2008; 36:6523-34. [PMID: 18927113 PMCID: PMC2582616 DOI: 10.1093/nar/gkn737] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
X-linked juvenile retinoschisis is a heritable condition of the retina in males caused by mutations in the RS1 gene. Still, the cellular function and retina-specific expression of RS1 are poorly understood. To address the latter issue, we characterized the minimal promoter driving expression of RS1 in the retina. Binding site prediction, site-directed mutagenesis, and reporter assays suggest an essential role of two nearby cone-rod homeobox (CRX)-responsive elements (CRE) in the proximal −177/+32 RS1 promoter. Chromatin immunoprecipitation associates the RS1 promoter in vivo with CRX, the coactivators CBP, P300, GCN5 and acetylated histone H3. Transgenic Xenopus laevis expressing a green fluorescent protein (GFP) reporter under the control of RS1 promoter sequences show that the −177/+32 fragment drives GFP expression in photoreceptors and bipolar cells. Mutating either of the two conserved CRX binding sites results in strongly decreased RS1 expression. Despite the presence of sequence motifs in the promoter, NRL and NR2E3 appear not to be essential for RS1 expression. Together, our in vitro and in vivo results indicate that two CRE sites in the minimal RS1 promoter region control retinal RS1 expression and establish CRX as a key factor driving this expression.
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Affiliation(s)
- Thomas Langmann
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
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Esumi N, Kachi S, Hackler L, Masuda T, Yang Z, Campochiaro PA, Zack DJ. BEST1 expression in the retinal pigment epithelium is modulated by OTX family members. Hum Mol Genet 2008; 18:128-41. [PMID: 18849347 DOI: 10.1093/hmg/ddn323] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A number of genes preferentially expressed in the retinal pigment epithelium (RPE) are associated with retinal degenerative disease. One of these, BEST1, encodes bestrophin-1, a protein that when mutated causes Best macular dystrophy. As a model for RPE gene regulation, we have been studying the mechanisms that control BEST1 expression, and recently demonstrated that members of the MITF-TFE family modulate BEST1 transcription. The human BEST1 upstream region from -154 to +38 bp is sufficient to direct expression in the RPE, and positive-regulatory elements exist between -154 and -104 bp. Here, we show that the -154 to -104 bp region is necessary for RPE expression in transgenic mice and contains a predicted OTX-binding site (Site 1). Since another non-canonical OTX site (Site 2) is located nearby, we tested the function of these sites using BEST1 promoter/luciferase constructs by in vivo electroporation and found that mutation of both sites reduces promoter activity. Three OTX family proteins - OTX1, OTX2 and CRX - bound to both Sites 1 and 2 in vitro, and all of them increased BEST1 promoter activity. Surprisingly, we found that human and bovine RPE expressed not only OTX2 but also CRX, the CRX genomic region in bovine RPE was hypersensitive to DNase I, consistent with active transcription, and that both OTX2 and CRX bound to the BEST1 proximal promoter in vivo. These results demonstrate for the first time CRX expression in the RPE, and suggest that OTX2 and CRX may act as positive modulators of the BEST1 promoter in the RPE.
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Affiliation(s)
- Noriko Esumi
- The Guerrieri Center for Genetic Engineering and Molecular Ophthalmology at The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287-9289, USA
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Experience-Dependent Transfer of Otx2 Homeoprotein into the Visual Cortex Activates Postnatal Plasticity. Cell 2008; 134:508-20. [DOI: 10.1016/j.cell.2008.05.054] [Citation(s) in RCA: 363] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 04/22/2008] [Accepted: 05/05/2008] [Indexed: 11/21/2022]
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A new GFP-tagged line reveals unexpected Otx2 protein localization in retinal photoreceptors. BMC DEVELOPMENTAL BIOLOGY 2007; 7:122. [PMID: 17980036 PMCID: PMC2204009 DOI: 10.1186/1471-213x-7-122] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Accepted: 11/02/2007] [Indexed: 12/03/2022]
Abstract
Background Dynamic monitoring of protein expression and localization is fundamental to the understanding of biological processes. The paired-class homeodomain-containing transcription factor Otx2 is essential for normal head and brain development in vertebrates. Recent conditional knockout studies have pointed to multiple roles of this protein during late development and post-natal life. Yet, later expression and functions remain poorly characterized as specific reagents to detect the protein at any stage of development are still missing. Results We generated a new mouse line harbouring an insertion of the GFP gene within the Otx2 coding sequence to monitor the gene activity while preserving most of its functions. Our results demonstrate that this line represents a convenient tool to capture the dynamics of Otx2 gene expression from early embryonic stages to adulthood. In addition, we could visualize the intracellular location of Otx2 protein. In the retina, we reinterpret the former view of protein distribution and show a further level of regulation of intranuclear protein localization, which depends on the cell type. Conclusion The GFP-tagged Otx2 mouse line fully recapitulates previously known expression patterns and brings additional accuracy and easiness of detection of Otx2 gene activity. This opens up the way to live imaging of a highly dynamic actor of brain development and can be adapted to any mutant background to probe for genetic interaction between Otx2 and the mutated gene.
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