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Bosze B, Suarez-Navarro J, Cajias I, Brzezinski IV JA, Brown NL. Notch pathway mutants do not equivalently perturb mouse embryonic retinal development. PLoS Genet 2023; 19:e1010928. [PMID: 37751417 PMCID: PMC10522021 DOI: 10.1371/journal.pgen.1010928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 08/16/2023] [Indexed: 09/28/2023] Open
Abstract
In the vertebrate eye, Notch ligands, receptors, and ternary complex components determine the destiny of retinal progenitor cells in part by regulating Hes effector gene activity. There are multiple paralogues for nearly every node in this pathway, which results in numerous instances of redundancy and compensation during development. To dissect such complexity at the earliest stages of eye development, we used seven germline or conditional mutant mice and two spatiotemporally distinct Cre drivers. We perturbed the Notch ternary complex and multiple Hes genes to understand if Notch regulates optic stalk/nerve head development; and to test intracellular pathway components for their Notch-dependent versus -independent roles during retinal ganglion cell and cone photoreceptor competence and fate acquisition. We confirmed that disrupting Notch signaling universally blocks progenitor cell growth, but delineated specific pathway components that can act independently, such as sustained Hes1 expression in the optic stalk/nerve head. In retinal progenitor cells, we found that among the genes tested, they do not uniformly suppress retinal ganglion cell or cone differentiation; which is not due differences in developmental timing. We discovered that shifts in the earliest cell fates correlate with expression changes for the early photoreceptor factor Otx2, but not with Atoh7, a factor required for retinal ganglion cell formation. During photoreceptor genesis we also better defined multiple and simultaneous activities for Rbpj and Hes1 and identify redundant activities that occur downstream of Notch. Given its unique roles at the retina-optic stalk boundary and cone photoreceptor genesis, our data suggest Hes1 as a hub where Notch-dependent and -independent inputs converge.
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Affiliation(s)
- Bernadett Bosze
- Department of Cell Biology & Human Anatomy, University of California, Davis, California, United States of America
| | - Julissa Suarez-Navarro
- Department of Cell Biology & Human Anatomy, University of California, Davis, California, United States of America
| | - Illiana Cajias
- Department of Cell Biology & Human Anatomy, University of California, Davis, California, United States of America
| | - Joseph A. Brzezinski IV
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Nadean L. Brown
- Department of Cell Biology & Human Anatomy, University of California, Davis, California, United States of America
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2
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Davari M, Soheili ZS, Latifi-Navid H, Samiee S. Potential involvement of miR-183/96/182 cluster-gene target interactions in transdifferentiation of human retinal pigment epithelial cells into retinal neurons. Biochem Biophys Res Commun 2023; 663:87-95. [PMID: 37119770 DOI: 10.1016/j.bbrc.2023.04.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/12/2023] [Accepted: 04/16/2023] [Indexed: 05/01/2023]
Abstract
miR-183/96/182 cluster plays a critical role in the developing retina by regulating many target genes involved in signaling pathways. This study aimed to survey the miR-183/96/182 cluster-target interactions that, potentially contribute to human retinal pigmented epithelial (hRPE) cell differentiation into photoreceptors. Target genes of the miR-183/96/182 cluster were obtained from miRNA-target databases and applied to construct miRNA-target networks. Gene ontology and KEGG pathway analysis was performed. miR-183/96/182 cluster sequence was cloned into an eGFP-intron splicing cassette in an AAV2 vector and overexpressed in hRPE cells. The expression level of target genes including HES1, PAX6, SOX2, CCNJ, and RORΒ was evaluated using qPCR. Our results showed that miR-183, miR-96, and miR-182 share 136 target genes that are involved in cell proliferation pathways such as PI3K/AKT and MAPK pathway. qPCR data indicated a 22-, 7-, and 4-fold overexpression of miR-183, miR-96, and miR-182, respectively, in infected hRPE cells. Consequently, the downregulation of several key targets such as PAX6, CCND2, CDK5R1, and CCNJ and upregulation of a few retina-specific neural markers such as Rhodopsin, red opsin, and CRX was detected. Our findings suggest that the miR-183/96/182 cluster may induce hRPE transdifferentiation by targeting key genes that involve in the cell cycle and proliferation pathways.
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Affiliation(s)
- Maliheh Davari
- Molecular Medicine Department, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Zahra-Soheila Soheili
- Molecular Medicine Department, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
| | - Hamid Latifi-Navid
- Molecular Medicine Department, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Shahram Samiee
- Blood Transfusion Research Center High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
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3
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Bosze B, Suarez-Navarro J, Cajias I, Brzezinski JA, Brown NL. Not all Notch pathway mutations are equal in the embryonic mouse retina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.11.523641. [PMID: 36711950 PMCID: PMC9882158 DOI: 10.1101/2023.01.11.523641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In the vertebrate retina, combinations of Notch ligands, receptors, and ternary complex components determine the destiny of retinal progenitor cells by regulating Hes effector gene activity. Owing to reiterated Notch signaling in numerous tissues throughout development, there are multiple vertebrate paralogues for nearly every node in this pathway. These Notch signaling components can act redundantly or in a compensatory fashion during development. To dissect the complexity of this pathway during retinal development, we used seven germline or conditional mutant mice and two spatiotemporally distinct Cre drivers. We perturbed the Notch ternary complex and multiple Hes genes with two overt goals in mind. First, we wished to determine if Notch signaling is required in the optic stalk/nerve head for Hes1 sustained expression and activity. Second, we aimed to test if Hes1, 3 and 5 genes are functionally redundant during early retinal histogenesis. With our allelic series, we found that disrupting Notch signaling consistently blocked mitotic growth and overproduced ganglion cells, but we also identified two significant branchpoints for this pathway. In the optic stalk/nerve head, sustained Hes1 is regulated independent of Notch signaling, whereas during photoreceptor genesis both Notch-dependent and -independent roles for Rbpj and Hes1 impact photoreceptor genesis in opposing manners.
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Affiliation(s)
- Bernadett Bosze
- Department of Cell Biology & Human Anatomy, University of California, Davis, CA 95616
| | | | - Illiana Cajias
- Department of Cell Biology & Human Anatomy, University of California, Davis, CA 95616
| | - Joseph A. Brzezinski
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Nadean L Brown
- Department of Cell Biology & Human Anatomy, University of California, Davis, CA 95616
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4
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Li X, Gordon PJ, Gaynes JA, Fuller AW, Ringuette R, Santiago CP, Wallace V, Blackshaw S, Li P, Levine EM. Lhx2 is a progenitor-intrinsic modulator of Sonic Hedgehog signaling during early retinal neurogenesis. eLife 2022; 11:e78342. [PMID: 36459481 PMCID: PMC9718532 DOI: 10.7554/elife.78342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 11/09/2022] [Indexed: 12/03/2022] Open
Abstract
An important question in organogenesis is how tissue-specific transcription factors interact with signaling pathways. In some cases, transcription factors define the context for how signaling pathways elicit tissue- or cell-specific responses, and in others, they influence signaling through transcriptional regulation of signaling components or accessory factors. We previously showed that during optic vesicle patterning, the Lim-homeodomain transcription factor Lhx2 has a contextual role by linking the Sonic Hedgehog (Shh) pathway to downstream targets without regulating the pathway itself. Here, we show that during early retinal neurogenesis in mice, Lhx2 is a multilevel regulator of Shh signaling. Specifically, Lhx2 acts cell autonomously to control the expression of pathway genes required for efficient activation and maintenance of signaling in retinal progenitor cells. The Shh co-receptors Cdon and Gas1 are candidate direct targets of Lhx2 that mediate pathway activation, whereas Lhx2 directly or indirectly promotes the expression of other pathway components important for activation and sustained signaling. We also provide genetic evidence suggesting that Lhx2 has a contextual role by linking the Shh pathway to downstream targets. Through these interactions, Lhx2 establishes the competence for Shh signaling in retinal progenitors and the context for the pathway to promote early retinal neurogenesis. The temporally distinct interactions between Lhx2 and the Shh pathway in retinal development illustrate how transcription factors and signaling pathways adapt to meet stage-dependent requirements of tissue formation.
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Affiliation(s)
- Xiaodong Li
- Vanderbilt Eye Institute, Vanderbilt University Medical CenterNashvilleUnited States
| | - Patrick J Gordon
- John A. Moran Eye Center, University of UtahSalt Lake CityUnited States
| | - John A Gaynes
- John A. Moran Eye Center, University of UtahSalt Lake CityUnited States
| | - Alexandra W Fuller
- Department of Cell and Developmental Biology, Vanderbilt UniversityNashvilleUnited States
| | - Randy Ringuette
- Cellular and Molecular Medicine, University of OttawaOttawaCanada
| | - Clayton P Santiago
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Valerie Wallace
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health NetworkTorontoCanada
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Pulin Li
- Whitehead Institute of Biomedical Research, Department of Biology, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Edward M Levine
- Vanderbilt Eye Institute, Vanderbilt University Medical CenterNashvilleUnited States
- John A. Moran Eye Center, University of UtahSalt Lake CityUnited States
- Department of Cell and Developmental Biology, Vanderbilt UniversityNashvilleUnited States
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5
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Yin Y, Wu S, Niu L, Huang S. A ZFP42/MARK2 regulatory network reduces the damage of retinal ganglion cells in glaucoma: a study based on GEO dataset and in vitro experiments. Apoptosis 2022; 27:1049-1059. [PMID: 36131186 DOI: 10.1007/s10495-022-01746-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2022] [Indexed: 11/02/2022]
Abstract
Glaucoma is a common disorder in which the death of retinal ganglion cells (RGCs) results in a progressive loss of sight, even blindness. This study was performed to reveal the key molecular mechanism of RGC damage in glaucoma based on the Gene Expression Omnibus database. Glaucoma-related microarray datasets were identified, followed by collection of differentially expressed genes (DEGs) with the key genes discovered by weighted gene co-expression network analysis. Through LASSO regression analysis, candidate genes involved in the pathogenesis of glaucoma were identified with their accuracy evaluated by receiver operating characteristic curve analysis. The glaucoma-specific transcriptional regulatory network was constructed to determine the key transcription factor regulatory axis. Then, in vitro cell models were established using H2O2 for further verifying the regulatory role of identified ZFP42/MARK2 axis in RGC damage in glaucoma. Differential analysis of GSE27276, GSE45570, and GSE101727 microarray datasets yielded 165 DEGs, and 22 key genes were identified following. Then, 9 candidate genes involved in the pathogenesis of glaucoma was collected and the key ZFP42/MARK2 regulatory axis was found. In vitro cell experiments further confirmed that ZFP42 and MARK2 were down-regulated in RGCs treated with H2O2. In addition, overexpression of ZFP42 increased the expression of MARK2 to increase RGC cell viability, and reduce cell apoptosis and ROS levels, while silencing MARK2 could reverse the protective effect of ZFP42. We confirmed that ZFP42 reduced the damage of RGCs in glaucoma by up-regulating the expression of MARK2.
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Affiliation(s)
- Yuan Yin
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130042, Jilin, People's Republic of China
| | - Shuai Wu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130042, Jilin, People's Republic of China
| | - Lingzhi Niu
- Department of Ophthalmology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, People's Republic of China
| | - Shiwei Huang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130042, Jilin, People's Republic of China.
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Loss of Hes1 in embryonic stem cells caused developmental disorders in retinal pigment epithelium morphogenesis and specification. Biochem Biophys Res Commun 2022; 632:76-84. [DOI: 10.1016/j.bbrc.2022.09.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 08/23/2022] [Accepted: 09/21/2022] [Indexed: 11/20/2022]
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7
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Bery A, Bagchi U, Bergen AA, Felder-Schmittbuhl MP. Circadian clocks, retinogenesis and ocular health in vertebrates: new molecular insights. Dev Biol 2022; 484:40-56. [DOI: 10.1016/j.ydbio.2022.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/21/2022] [Accepted: 02/01/2022] [Indexed: 12/22/2022]
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Menuchin-Lasowski Y, Dagan B, Conidi A, Cohen-Gulkar M, David A, Ehrlich M, Giladi PO, Clark BS, Blackshaw S, Shapira K, Huylebroeck D, Henis YI, Ashery-Padan R. Zeb2 regulates the balance between retinal interneurons and Müller glia by inhibition of BMP-Smad signaling. Dev Biol 2020; 468:80-92. [PMID: 32950463 DOI: 10.1016/j.ydbio.2020.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 08/24/2020] [Accepted: 09/10/2020] [Indexed: 12/27/2022]
Abstract
The interplay between signaling molecules and transcription factors during retinal development is key to controlling the correct number of retinal cell types. Zeb2 (Sip1) is a zinc-finger multidomain transcription factor that plays multiple roles in central and peripheral nervous system development. Haploinsufficiency of ZEB2 causes Mowat-Wilson syndrome, a congenital disease characterized by intellectual disability, epilepsy and Hirschsprung disease. In the developing retina, Zeb2 is required for generation of horizontal cells and the correct number of interneurons; however, its potential function in controlling gliogenic versus neurogenic decisions remains unresolved. Here we present cellular and molecular evidence of the inhibition of Müller glia cell fate by Zeb2 in late stages of retinogenesis. Unbiased transcriptomic profiling of control and Zeb2-deficient early-postnatal retina revealed that Zeb2 functions in inhibiting Id1/2/4 and Hes1 gene expression. These neural progenitor factors normally inhibit neural differentiation and promote Müller glia cell fate. Chromatin immunoprecipitation (ChIP) supported direct regulation of Id1 by Zeb2 in the postnatal retina. Reporter assays and ChIP analyses in differentiating neural progenitors provided further evidence that Zeb2 inhibits Id1 through inhibition of Smad-mediated activation of Id1 transcription. Together, the results suggest that Zeb2 promotes the timely differentiation of retinal interneurons at least in part by repressing BMP-Smad/Notch target genes that inhibit neurogenesis. These findings show that Zeb2 integrates extrinsic cues to regulate the balance between neuronal and glial cell types in the developing murine retina.
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Affiliation(s)
- Yotam Menuchin-Lasowski
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Bar Dagan
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Andrea Conidi
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam 3015 CN, the Netherlands
| | - Mazal Cohen-Gulkar
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ahuvit David
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Marcelo Ehrlich
- Shumins School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Pazit Oren Giladi
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Brian S Clark
- John F Hardesty, MD Department of Ophthalmology and Visual Sciences and Department of Developmental Biology, Washington University, St. Louis, MO 63110, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Baltimore, MD 21205, USA; Department of Ophthalmology, Baltimore, MD 21205, USA; Department of Neurology, Baltimore, MD 21205, USA; Center for Human Systems Biology, Baltimore, MD 21205, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Keren Shapira
- Shumins School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Danny Huylebroeck
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam 3015 CN, the Netherlands; Department of Development and Regeneration, KU Leuven, Leuven 3000, Belgium
| | - Yoav I Henis
- Shumins School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ruth Ashery-Padan
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
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9
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Simultaneous Requirements for Hes1 in Retinal Neurogenesis and Optic Cup-Stalk Boundary Maintenance. J Neurosci 2020; 40:1501-1513. [PMID: 31949107 DOI: 10.1523/jneurosci.2327-19.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/02/2020] [Accepted: 01/07/2020] [Indexed: 12/15/2022] Open
Abstract
The bHLH transcription factor Hes1 is a key downstream effector for the Notch signaling pathway. During embryogenesis neural progenitors express low levels of Hes1 in an oscillating pattern, whereas glial brain boundary regions (e.g., isthmus) have high, sustained Hes1 levels that suppress neuronal fates. Here, we show that in the embryonic mouse retina, the optic nerve head and stalk express high Hes1, with the ONH constituting a boundary between the neural retina and glial cells that ultimately line the optic stalk. Using two Cre drivers with distinct spatiotemporal expression we conditionally inactivated Hes1, to delineate the requirements for this transcriptional repressor during retinal neurogenesis versus patterning of the optic cup and stalk. Throughout retinal neurogenesis, Hes1 maintains proliferation and blocks retinal ganglion cell formation, but surprisingly we found it also promotes cone photoreceptor genesis. In the postnatal eye, Hes1 inactivation with Rax-Cre resulted in increased bipolar neurons and a mispositioning of Müller glia. Our results indicate that Notch pathway regulation of cone genesis is more complex than previously assumed, and reveal a novel role for Hes1 in maintaining the optic cup-stalk boundary.SIGNIFICANCE STATEMENT The bHLH repressor Hes1 regulates the timing of neurogenesis, rate of progenitor cell division, gliogenesis, and maintains tissue compartment boundaries. This study expands current eye development models by showing Notch-independent roles for Hes1 in the developing optic nerve head (ONH). Defects in ONH formation result in optic nerve coloboma; our work now inserts Hes1 into the genetic hierarchy regulating optic fissure closure. Given that Hes1 acts analogously in the ONH as the brain isthmus, it prompts future investigation of the ONH as a signaling factor center, or local organizer. Embryonic development of the ONH region has been poorly studied, which is surprising given it is where the pan-ocular disease glaucoma is widely believed to inflict damage on RGC axons.
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10
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Wiegering A, Petzsch P, Köhrer K, Rüther U, Gerhardt C. GLI3 repressor but not GLI3 activator is essential for mouse eye patterning and morphogenesis. Dev Biol 2019; 450:141-154. [PMID: 30953627 DOI: 10.1016/j.ydbio.2019.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/12/2019] [Accepted: 02/15/2019] [Indexed: 12/11/2022]
Abstract
Since 1967, it is known that the loss of GLI3 causes very severe defects in murine eye development. GLI3 is able to act as a transcriptional activator (GLI3-A) or as a transcriptional repressor (GLI3-R). Soon after the discovery of these GLI3 isoforms, the question arose which of the different isoforms is involved in eye formation - GLI3-A, GLI3-R or even both. For several years, this question remained elusive. By analysing the eye morphogenesis of Gli3XtJ/XtJ mouse embryos that lack GLI3-A and GLI3-R and of Gli3Δ699/Δ699 mouse embryos in which only GLI3-A is missing, we revealed that GLI3-A is dispensable in vertebrate eye formation. Remarkably, our study shows that GLI3-R is sufficient for the creation of morphologically normal eyes although the molecular setup deviates substantially from normality. In depth-investigations elucidated that GLI3-R controls numerous key players in eye development and governs lens and retina development at least partially via regulating WNT/β-CATENIN signalling.
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Affiliation(s)
- Antonia Wiegering
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Patrick Petzsch
- Biological and Medical Research Center (BMFZ), Genomics and Transcriptomics Laboratory (GTL), Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Karl Köhrer
- Biological and Medical Research Center (BMFZ), Genomics and Transcriptomics Laboratory (GTL), Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Ulrich Rüther
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.
| | - Christoph Gerhardt
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.
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11
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Teotia P, Van Hook MJ, Wichman CS, Allingham RR, Hauser MA, Ahmad I. Modeling Glaucoma: Retinal Ganglion Cells Generated from Induced Pluripotent Stem Cells of Patients with SIX6 Risk Allele Show Developmental Abnormalities. Stem Cells 2017; 35:2239-2252. [PMID: 28792678 DOI: 10.1002/stem.2675] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/14/2017] [Accepted: 07/18/2017] [Indexed: 01/01/2023]
Abstract
Glaucoma represents a group of multifactorial diseases with a unifying pathology of progressive retinal ganglion cell (RGC) degeneration, causing irreversible vision loss. To test the hypothesis that RGCs are intrinsically vulnerable in glaucoma, we have developed an in vitro model using the SIX6 risk allele carrying glaucoma patient-specific induced pluripotent stem cells (iPSCs) for generating functional RGCs. Here, we demonstrate that the efficiency of RGC generation by SIX6 risk allele iPSCs is significantly lower than iPSCs-derived from healthy, age- and sex-matched controls. The decrease in the number of RGC generation is accompanied by repressed developmental expression of RGC regulatory genes. The SIX6 risk allele RGCs display short and simple neurites, reduced expression of guidance molecules, and immature electrophysiological signature. In addition, these cells have higher expression of glaucoma-associated genes, CDKN2A and CDKN2B, suggesting an early onset of the disease phenotype. Consistent with the developmental abnormalities, the SIX6 risk allele RGCs display global dysregulation of genes which map on developmentally relevant biological processes for RGC differentiation and signaling pathways such as mammalian target of rapamycin that integrate diverse functions for differentiation, metabolism, and survival. The results suggest that SIX6 influences different stages of RGC differentiation and their survival; therefore, alteration in SIX6 function due to the risk allele may lead to cellular and molecular abnormalities. These abnormalities, if carried into adulthood, may make RGCs vulnerable in glaucoma. Stem Cells 2017;35:2239-2252.
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Affiliation(s)
- Pooja Teotia
- Department of Ophthalmology and Visual Sciences, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Matthew J Van Hook
- Department of Ophthalmology and Visual Sciences, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Christopher S Wichman
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - R Rand Allingham
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Michael A Hauser
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Iqbal Ahmad
- Department of Ophthalmology and Visual Sciences, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, USA
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12
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Riesenberg AN, Conley KW, Le TT, Brown NL. Separate and coincident expression of Hes1 and Hes5 in the developing mouse eye. Dev Dyn 2017; 247:212-221. [PMID: 28675662 DOI: 10.1002/dvdy.24542] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Notch signaling is broadly required during embryogenesis, frequently activating the transcription of two basic helix-loop-helix transcription factors, Hes1 and Hes5. But, it remains unresolved when and where Hes1 and Hes5 act alone or together during development. Here, we analyzed a Hes5-green fluorescent protein (GFP) bacterial artificial chromosome (BAC) transgenic mouse, as a proxy for endogenous Hes5. We directly compared transgenic GFP expression with Hes1, and particular markers of embryonic lens and retina development. RESULTS Hes5-GFP is dynamic within subsets of retinal and lens progenitor cells, and differentiating retinal ganglion neurons, in contrast to Hes1 found in all progenitor cells. In the adult retina, only Müller glia express Hes5-GFP. Finally, Hes5-GFP is up-regulated in Hes1 germline mutants, consistent with previous demonstration that Hes1 suppresses Hes5 transcription. CONCLUSIONS Hes5-GFP BAC transgenic mice are useful for identifying Hes5-expressing cells. Although Hes5-GFP and Hes1 are coexpressed in particular developmental contexts, we also noted cohorts of lens or retinal cells expressing just one factor. The dynamic Hes5-GFP expression pattern, coupled with its derepressed expression in Hes1 mutants, suggests that this transgene contains the relevant cis-regulatory elements that regulate endogenous Hes5 in the mouse lens and retina. Developmental Dynamics 247:212-221, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Amy N Riesenberg
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, Ohio
| | - Kevin W Conley
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, Ohio
| | - Tien T Le
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, Ohio
| | - Nadean L Brown
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, Ohio.,Department of Cell Biology & Human Anatomy, University of California Davis, Davis, California
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13
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Dhanesh SB, Subashini C, James J. Hes1: the maestro in neurogenesis. Cell Mol Life Sci 2016; 73:4019-42. [PMID: 27233500 PMCID: PMC11108451 DOI: 10.1007/s00018-016-2277-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/12/2016] [Accepted: 05/12/2016] [Indexed: 10/21/2022]
Abstract
The process of neurogenesis is well orchestrated by the harmony of multiple cues in a spatiotemporal manner. In this review, we focus on how a dynamic gene, Hes1, is involved in neurogenesis with the view of its regulation and functional implications. Initially, we have reviewed the immense functional significance drawn by this maestro during neural development in a context-dependent manner. How this indispensable role of Hes1 in conferring the competency for neural differentiation partly relies on the direct/indirect mode of repression mediated by very specific structural and functional arms of this protein has also been outlined here. We also review the detailed molecular mechanisms behind the well-tuned oscillatory versus sustained expression of this antineurogenic bHLH repressor, which indeed makes it a master gene to implement the elusive task of neural progenitor propensity. Apart from the functional aspects of Hes1, we also discuss the molecular insights into the endogenous regulatory machinery that regulates its expression. Though Hes1 is a classical target of the Notch signaling pathway, we discuss here its differential expression at the molecular, cellular, and/or regional level. Moreover, we describe how its expression is fine-tuned by all possible ways of gene regulation such as epigenetic, transcriptional, post-transcriptional, post-translational, and environmental factors during vertebrate neurogenesis.
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Affiliation(s)
- Sivadasan Bindu Dhanesh
- Neuro Stem Cell Biology Laboratory, Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thycaud PO, Thiruvananthapuram, 695 014, Kerala, India
| | - Chandramohan Subashini
- Neuro Stem Cell Biology Laboratory, Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thycaud PO, Thiruvananthapuram, 695 014, Kerala, India
| | - Jackson James
- Neuro Stem Cell Biology Laboratory, Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thycaud PO, Thiruvananthapuram, 695 014, Kerala, India.
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14
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Toonen JA, Ronchetti A, Sidjanin DJ. A Disintegrin and Metalloproteinase10 (ADAM10) Regulates NOTCH Signaling during Early Retinal Development. PLoS One 2016; 11:e0156184. [PMID: 27224017 PMCID: PMC4880208 DOI: 10.1371/journal.pone.0156184] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 05/10/2016] [Indexed: 01/22/2023] Open
Abstract
ADAM10 and ADAM17 are two closely related members of the ADAM (a disintegrin and metalloprotease) family of membrane-bound sheddases, which proteolytically cleave surface membrane proteins. Both ADAM10 and ADAM17 have been implicated in the proteolytic cleavage of NOTCH receptors and as such regulators of NOTCH signaling. During retinal development, NOTCH signaling facilitates retinal neurogenesis by maintaining progenitor cells in a proliferative state and by mediating retinal cell fates. However, the roles of ADAM10 and ADAM17 in the retina are not well defined. In this study, we set out to clarify the roles of ADAM10 and ADAM17 during early retinal development. The retinal phenotype of conditionally abated Adam17 retinae (Adam17 CKO) did not differ from the controls whereas conditionally ablated Adam10 retinae (Adam10 CKO) exhibited abnormal morphogenesis characterized by the formation of rosettes and a loss of retinal laminae phenotypically similar to morphological abnormalities identified in mice with retinal NOTCH signaling deficiency. Additionally, Adam10 CKO retinae exhibited abnormal neurogenesis characterized by fewer proliferating progenitor cells and greater differentiation of early photoreceptors and retinal ganglion cells. Moreover, constitutive activation of the NOTCH1-intracellular domain (N1-ICD) rescued Adam10 CKO abnormal neurogenesis, as well as abnormal retinal morphology by maintaining retinal cells in the progenitor state. Collectively these findings provide in vivo genetic evidence that ADAM10, and not ADAM17, is indispensable for proper retinal development as a regulator of NOTCH signaling.
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Affiliation(s)
- Joseph A. Toonen
- Department of Cell Biology, Neurobiology, and Anatomy, 8701 Watertown Plank Rd., Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Adam Ronchetti
- Department of Cell Biology, Neurobiology, and Anatomy, 8701 Watertown Plank Rd., Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - D. J. Sidjanin
- Department of Cell Biology, Neurobiology, and Anatomy, 8701 Watertown Plank Rd., Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Human and Molecular Genetics Center, 8701 Watertown Plank Rd., Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
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Ringuette R, Atkins M, Lagali PS, Bassett EA, Campbell C, Mazerolle C, Mears AJ, Picketts DJ, Wallace VA. A Notch-Gli2 axis sustains Hedgehog responsiveness of neural progenitors and Müller glia. Dev Biol 2016; 411:85-100. [PMID: 26795056 DOI: 10.1016/j.ydbio.2016.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 01/05/2016] [Accepted: 01/11/2016] [Indexed: 11/18/2022]
Abstract
Neurogenesis is regulated by the dynamic and coordinated activity of several extracellular signalling pathways, but the basis for crosstalk between these pathways remains poorly understood. Here we investigated regulatory interactions between two pathways that are each required for neural progenitor cell maintenance in the postnatal retina; Hedgehog (Hh) and Notch signalling. Both pathways are activated in progenitor cells in the postnatal retina based on the co-expression of fluorescent pathway reporter transgenes at the single cell level. Disrupting Notch signalling, genetically or pharmacologically, induces a rapid downregulation of all three Gli proteins and inhibits Hh-induced proliferation. Ectopic Notch activation, while not sufficient to promote Hh signalling or proliferation, increases Gli2 protein. We show that Notch regulation of Gli2 in Müller glia renders these cells competent to proliferate in response to Hh. These data suggest that Notch signalling converges on Gli2 to prime postnatal retinal progenitor cells and Müller glia to proliferate in response to Hh.
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Affiliation(s)
- Randy Ringuette
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5
| | - Michael Atkins
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6
| | - Pamela S Lagali
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6
| | - Erin A Bassett
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6
| | - Charles Campbell
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5
| | - Chantal Mazerolle
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6
| | - Alan J Mears
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6
| | - David J Picketts
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6; Department of Biochemistry, Microbiology and Immunology, Department of Ophthalmology, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5
| | - Valerie A Wallace
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6; Department of Biochemistry, Microbiology and Immunology, Department of Ophthalmology, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5; Vision Research Division, Krembil Research Institute, University Health Network and Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada.
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16
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Li WH, Zhou L, Li Z, Wang Y, Shi JT, Yang YJ, Gui JF. Zebrafish Lbh-like Is Required for Otx2-mediated Photoreceptor Differentiation. Int J Biol Sci 2015; 11:688-700. [PMID: 25999792 PMCID: PMC4440259 DOI: 10.7150/ijbs.11244] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 04/11/2015] [Indexed: 12/12/2022] Open
Abstract
The homeobox transcription factor orthodenticle homolog 2 (otx2) is supposed as an organizer that orchestrates a transcription factor network during photoreceptor development. However, its regulation in the process remains unclear. In this study, we have identified a zebrafish limb bud and heart-like gene (lbh-like), which is expressed initially at 30 hours post fertilization (hpf) in the developing brain and eyes. Lbh-like knockdown by morpholinos specifically inhibits expression of multiple photoreceptor-specific genes, such as opsins, gnat1, gnat2 and irbp. Interestingly, otx2 expression in the morphants is not significantly reduced until 32 hpf when lbh-like begins to express, but its expression level in 72 hpf morphants is higher than that in wild type embryos. Co-injection of otx2 and its downstream target neuroD mRNAs can rescue the faults in eyes of Lbh-like morphants. Combined with the results of promoter-reporter assay, we suggest that lbh-like is a new regulator of photoreceptor differentiation directly through affecting otx2 expression in zebrafish. Furthermore, knockdown of lbh-like increases the activity of Notch pathway and perturbs the balance among proliferation, differentiation and survival of photoreceptor precursors.
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Affiliation(s)
- Wen-Hua Li
- 1. State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, ; 2. Graduate University of the Chinese Academy of Sciences, Wuhan 430072, China
| | - Li Zhou
- 1. State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences
| | - Zhi Li
- 1. State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences
| | - Yang Wang
- 1. State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences
| | - Jian-Tao Shi
- 1. State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences
| | - Yan-Jing Yang
- 1. State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, ; 2. Graduate University of the Chinese Academy of Sciences, Wuhan 430072, China
| | - Jian-Fang Gui
- 1. State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences
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Sigulinsky CL, German ML, Leung AM, Clark AM, Yun S, Levine EM. Genetic chimeras reveal the autonomy requirements for Vsx2 in embryonic retinal progenitor cells. Neural Dev 2015; 10:12. [PMID: 25927996 PMCID: PMC4450477 DOI: 10.1186/s13064-015-0039-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 04/14/2015] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Vertebrate retinal development is a complex process, requiring the specification and maintenance of retinal identity, proliferative expansion of retinal progenitor cells (RPCs), and their differentiation into retinal neurons and glia. The homeobox gene Vsx2 is expressed in RPCs and required for the proper execution of this retinal program. However, our understanding of the mechanisms by which Vsx2 does this is still rudimentary. To define the autonomy requirements for Vsx2 in the regulation of RPC properties, we generated chimeric mouse embryos comprised of wild-type and Vsx2-deficient cells. RESULTS We show that Vsx2 maintains retinal identity in part through the cell-autonomous repression of the retinal pigment epithelium determinant Mitf, and that Lhx2 is required cell autonomously for the ectopic Mitf expression in Vsx2-deficient cells. We also found significant cell-nonautonomous contributions to Vsx2-mediated regulation of RPC proliferation, pointing to an important role for Vsx2 in establishing a growth-promoting extracellular environment. Additionally, we report a cell-autonomous requirement for Vsx2 in controlling when neurogenesis is initiated, indicating that Vsx2 is an important mediator of neurogenic competence. Finally, the distribution of wild-type cells shifted away from RPCs and toward retinal ganglion cell precursors in patches of high Vsx2-deficient cell density to potentially compensate for the lack of fated precursors in these areas. CONCLUSIONS Through the generation and analysis of genetic chimeras, we demonstrate that Vsx2 utilizes both cell-autonomous and cell-nonautonomous mechanisms to regulate progenitor properties in the embryonic retina. Importantly, Vsx2's role in regulating Mitf is in part separable from its role in promoting proliferation, and proliferation is excluded as the intrinsic timer that determines when neurogenesis is initiated. These findings highlight the complexity of Vsx2 function during retinal development and provide a framework for identifying the molecular mechanisms mediating these functions.
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Affiliation(s)
- Crystal L Sigulinsky
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Interdepartmental Program in Neuroscience, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Massiell L German
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Amanda M Leung
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Anna M Clark
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Sanghee Yun
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Edward M Levine
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
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18
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Maurer KA, Riesenberg AN, Brown NL. Notch signaling differentially regulates Atoh7 and Neurog2 in the distal mouse retina. Development 2014; 141:3243-54. [PMID: 25100656 DOI: 10.1242/dev.106245] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Notch signaling regulates basic helix-loop-helix (bHLH) factors as an evolutionarily conserved module, but the tissue-specific mechanisms are incompletely elucidated. In the mouse retina, bHLH genes Atoh7 and Neurog2 have distinct functions, with Atoh7 regulating retinal competence and Neurog2 required for progression of neurogenesis. These transcription factors are extensively co-expressed, suggesting similar regulation. We directly compared Atoh7 and Neurog2 regulation at the earliest stages of retinal neurogenesis in a broad spectrum of Notch pathway mutants. Notch1 and Rbpj normally block Atoh7 and Neurog2 expression. However, the combined activities of Notch1, Notch3 and Rbpj regulate Neurog2 patterning in the distal retina. Downstream of the Notch complex, we found the Hes1 repressor mediates Atoh7 suppression, but Hes1, Hes3 and Hes5 do not regulate Neurog2 expression. We also tested Notch-mediated regulation of Jag1 and Pax6 in the distal retina, to establish the appropriate context for Neurog2 patterning. We found that Notch1;Notch3 and Rbpj block co-expression of Jag1 and Neurog2, while specifically stimulating Pax6 within an adjacent domain. Our data suggest that Notch signaling controls the overall tempo of retinogenesis, by integrating cell fate specification, the wave of neurogenesis and the developmental status of cells ahead of this wave.
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Affiliation(s)
- Kate A Maurer
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA
| | - Amy N Riesenberg
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA
| | - Nadean L Brown
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA Department of Cell Biology and Human Anatomy, University of California Davis, School of Medicine, Davis, CA 95616, USA
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19
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Zhang Z, Yan R, Zhang Q, Li J, Kang X, Wang H, Huan L, Zhang L, Li F, Yang S, Zhang J, Ren X, Yang X. Hes1, a Notch signaling downstream target, regulates adult hippocampal neurogenesis following traumatic brain injury. Brain Res 2014; 1583:65-78. [PMID: 25084035 DOI: 10.1016/j.brainres.2014.07.037] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 07/21/2014] [Accepted: 07/22/2014] [Indexed: 01/23/2023]
Abstract
Hairy and enhancer of split 1 (Hes1), a downstream target of Notch signaling, has long been recognized as crucial in inhibiting neuronal differentiation. However, the role of Hes1 following traumatic brain injury (TBI) in adult neurogenesis in the mouse dentate gyrus (DG) remains partially understood. Here, we investigate the role of Hes1 in regulating neurogenesis in the DG of the adult hippocampus after TBI by up- or downregulating Hes1 expression. First, adenovirus-mediated gene transfection was employed to upregulate Hes1 in vivo. The mice were then subjected to TBI, and the hippocampal tissue was collected for Western blot analysis at designated times, pre- and post-injury. Moreover, the brain slices were stained for BrdU and doublecortin (DCX). We show that enhancing Hes1 inhibits the proliferation and differentiation of neural precursor cells (NPCs) in the DG of the hippocampus soon after TBI. Second, downregulation of Hes1 via RNA interference (RNAi) results in a significant increase in neuronal production and promotes the differentiation of NPCs into mature neurons in the DG, as assessed by BrdU and NeuN double staining. Furthermore, a Morris water maze (MWM) test clearly confirmed that the knockdown of Hes1 improves the spatial learning and memory capacity of adult mice following injury. Taken together, these observations suggest that Hes1 represents a negative regulator of adult neurogenesis post-TBI and that the precise space-time regulation of Hes1 expression in the DG may promote the recovery of neural function following TBI.
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Affiliation(s)
- Zhen Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China.
| | - Rong Yan
- Department of Neurosurgery, Tianjin 5th Central Hospital, Tianjin 300052, PR China.
| | - Qi Zhang
- Department of Neurosurgery, Binzhou Medical University Hospital, Binzhou 256603, PR China.
| | - Jia Li
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China.
| | - Xiaokui Kang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China.
| | - Haining Wang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China.
| | - Linchun Huan
- Department of Neurosurgery, Linyi People׳s Hospital, Linyi 276000, PR China.
| | - Lin Zhang
- Department of Neurosurgery, Tianjin 5th Central Hospital, Tianjin 300052, PR China.
| | - Fan Li
- Department of Neurosurgery, Heji Hospital affiliated Changzhi Medical College, 271 Taihang East Road, Changzhi 046000, PR China.
| | - Shuyuan Yang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China.
| | - Jianning Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China.
| | - Xinliang Ren
- Department of Neurosurgery, Heji Hospital affiliated Changzhi Medical College, 271 Taihang East Road, Changzhi 046000, PR China.
| | - Xinyu Yang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, PR China; Tianjin Neurological Institute, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, 154 Anshan Road, Heping District, Tianjin 300052, PR China.
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20
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Alves CH, Pellissier LP, Wijnholds J. The CRB1 and adherens junction complex proteins in retinal development and maintenance. Prog Retin Eye Res 2014; 40:35-52. [PMID: 24508727 DOI: 10.1016/j.preteyeres.2014.01.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/21/2014] [Accepted: 01/27/2014] [Indexed: 12/30/2022]
Abstract
The early developing retinal neuroepithelium is composed of multipotent retinal progenitor cells that differentiate in a time specific manner, giving rise to six major types of neuronal and one type of glial cells. These cells migrate and organize in three distinct nuclear layers divided by two plexiform layers. Apical and adherens junction complexes have a crucial role in this process by the establishment of polarity and adhesion. Changes in these complexes disturb the spatiotemporal aspects of retinogenesis, leading to retinal degeneration resulting in mild or severe impairment of retinal function and vision. In this review, we summarize the mouse models for the different members of the apical and adherens junction protein complexes and describe the main features of their retinal phenotypes. The knowledge acquired from the different mutant animals for these proteins corroborate their importance in retina development and maintenance of normal retinal structure and function. More recently, several studies have tried to unravel the connection between the apical proteins, important cellular signaling pathways and their relation in retina development. Still, the mechanisms by which these proteins function remain largely unknown. Here, we hypothesize how the mammalian apical CRB1 complex might control retinogenesis and prevents onset of Leber congenital amaurosis or retinitis pigmentosa.
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Affiliation(s)
- Celso Henrique Alves
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Lucie P Pellissier
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Jan Wijnholds
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
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21
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Yip HK. Retinal stem cells and regeneration of vision system. Anat Rec (Hoboken) 2013; 297:137-60. [PMID: 24293400 DOI: 10.1002/ar.22800] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 09/13/2013] [Indexed: 12/14/2022]
Abstract
The vertebrate retina is a well-characterized model for studying neurogenesis. Retinal neurons and glia are generated in a conserved order from a pool of mutlipotent progenitor cells. During retinal development, retinal stem/progenitor cells (RPC) change their competency over time under the influence of intrinsic (such as transcriptional factors) and extrinsic factors (such as growth factors). In this review, we summarize the roles of these factors, together with the understanding of the signaling pathways that regulate eye development. The information about the interactions between intrinsic and extrinsic factors for retinal cell fate specification is useful to regenerate specific retinal neurons from RPCs. Recent studies have identified RPCs in the retina, which may have important implications in health and disease. Despite the recent advances in stem cell biology, our understanding of many aspects of RPCs in the eye remains limited. PRCs are present in the developing eye of all vertebrates and remain active in lower vertebrates throughout life. In mammals, however, PRCs are quiescent and exhibit very little activity and thus have low capacity for retinal regeneration. A number of different cellular sources of RPCs have been identified in the vertebrate retina. These include PRCs at the retinal margin, pigmented cells in the ciliary body, iris, and retinal pigment epithelium, and Müller cells within the retina. Because PRCs can be isolated and expanded from immature and mature eyes, it is possible now to study these cells in culture and after transplantation in the degenerated retinal tissue. We also examine current knowledge of intrinsic RPCs, and human embryonic stems and induced pluripotent stem cells as potential sources for cell transplant therapy to regenerate the diseased retina.
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Affiliation(s)
- Henry K Yip
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Adminstrative Region, People's Republic of China; Research Center of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Adminstrative Region, People's Republic of China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong Special Adminstrative Region, People's Republic of China
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22
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El Yakoubi W, Borday C, Hamdache J, Parain K, Tran HT, Vleminckx K, Perron M, Locker M. Hes4 controls proliferative properties of neural stem cells during retinal ontogenesis. Stem Cells 2013; 30:2784-95. [PMID: 22969013 PMCID: PMC3549485 DOI: 10.1002/stem.1231] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 08/08/2012] [Indexed: 11/22/2022]
Abstract
The retina of fish and amphibian contains genuine neural stem cells located at the most peripheral edge of the ciliary marginal zone (CMZ). However, their cell-of-origin as well as the mechanisms that sustain their maintenance during development are presently unknown. We identified Hes4 (previously named XHairy2), a gene encoding a bHLH-O transcriptional repressor, as a stem cell-specific marker of the Xenopus CMZ that is positively regulated by the canonical Wnt pathway and negatively by Hedgehog signaling. We found that during retinogenesis, Hes4 labels a small territory, located first at the pigmented epithelium (RPE)/neural retina (NR) border and later in the retinal margin, that likely gives rise to adult retinal stem cells. We next addressed whether Hes4 might impart this cell subpopulation with retinal stem cell features: inhibited RPE or NR differentiation programs, continuous proliferation, and slow cell cycle speed. We could indeed show that Hes4 overexpression cell autonomously prevents retinal precursor cells from commitment toward retinal fates and maintains them in a proliferative state. Besides, our data highlight for the first time that Hes4 may also constitute a crucial regulator of cell cycle kinetics. Hes4 gain of function indeed significantly slows down cell division, mainly through the lengthening of G1 phase. As a whole, we propose that Hes4 maintains particular stemness features in a cellular cohort dedicated to constitute the adult retinal stem cell pool, by keeping it in an undifferentiated and slowly proliferative state along embryonic retinogenesis. Stem Cells 2012;30:2784–2795
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23
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Surzenko N, Crowl T, Bachleda A, Langer L, Pevny L. SOX2 maintains the quiescent progenitor cell state of postnatal retinal Muller glia. Development 2013; 140:1445-56. [PMID: 23462474 DOI: 10.1242/dev.071878] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Within discrete regions of the developing mammalian central nervous system, small subsets of glia become specialized to function as neural stem cells. As a result of their self-renewal and neurogenic capacity, these cells later serve to replenish neurons and glia during persistent or injury-induced adult neurogenesis. SOX2, an HMG box transcription factor, plays an essential role in the maintenance of both embryonic and adult neural progenitors. It is unclear, however, which biological mechanisms regulated by SOX2 are required for neural stem cell maintenance. In this study, we address this question through genetic analysis of SOX2 function in differentiating postnatal Müller glia, a cell type that maintains neurogenic capacity in the adult retina. By utilizing molecular analysis and real-time imaging, we show that two progenitor characteristics of nascent Müller glia - their radial morphology and cell cycle quiescence - are disrupted following conditional genetic ablation of Sox2 in the mouse postnatal retina, leading to Müller cell depletion and retinal degeneration. Moreover, we demonstrate that genetic induction of the Notch signaling pathway restores Müller glial cell identity to Sox2 mutant cells, but does not secure their quiescent state. Collectively, these results uncouple the roles of SOX2 and the Notch signaling pathway in the postnatal retina, and uncover a novel role for SOX2 in preventing the depletion of postnatal Müller glia through terminal cell division.
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Affiliation(s)
- Natalia Surzenko
- UNC Neuroscience Center, Department of Genetics, University of North Carolina, 115 Mason Farm Road, Chapel Hill, NC 27599, USA.
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An essential role for RAX homeoprotein and NOTCH-HES signaling in Otx2 expression in embryonic retinal photoreceptor cell fate determination. J Neurosci 2012; 31:16792-807. [PMID: 22090505 DOI: 10.1523/jneurosci.3109-11.2011] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The molecular mechanisms underlying cell fate determination from common progenitors in the vertebrate CNS remain elusive. We previously reported that the OTX2 homeoprotein regulates retinal photoreceptor cell fate determination. While Otx2 transactivation is a pivotal process for photoreceptor cell fate determination, its transactivation mechanism in the retina is unknown. Here, we identified an evolutionarily conserved Otx2 enhancer of ∼500 bp, named embryonic enhancer locus for photoreceptor Otx2 transcription (EELPOT), which can recapitulate initial Otx2 expression in the embryonic mouse retina. We found that the RAX homeoprotein interacts with EELPOT to transactivate Otx2, mainly in the final cell cycle of retinal progenitors. Conditional inactivation of Rax results in downregulation of Otx2 expression in vivo. We also showed that NOTCH-HES signaling negatively regulates EELPOT to suppress Otx2 expression. These results suggest that the integrated activity of cell-intrinsic and -extrinsic factors on EELPOT underlies the molecular basis of photoreceptor cell fate determination in the embryonic retina.
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25
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Zaghloul NA, Yan B, Moody SA. Step-wise specification of retinal stem cells during normal embryogenesis. Biol Cell 2012; 97:321-37. [PMID: 15836431 DOI: 10.1042/bc20040521] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The specification of embryonic cells to produce the retina begins at early embryonic stages as a multi-step process that gradually restricts fate potentials. First, a subset of embryonic cells becomes competent to form retina by their lack of expression of endo-mesoderm-specifying genes. From these cells, a more restricted subset is biased to form retina by virtue of their close proximity to sources of bone morphogenetic protein antagonists during neural induction. During gastrulation, the definitive RSCs (retinal stem cells) are specified as the eye field by interactions with underlying mesoderm and the expression of a network of retina-specifying genes. As the eye field is transformed into the optic vesicle and optic cup, a heterogeneous population of RPCs (retinal progenitor cells) forms to give rise to the different domains of the retina: the optic stalk, retinal pigmented epithelium and neural retina. Further diversity of RPCs appears to occur under the influences of cell-cell interactions, cytokines and combinations of regulatory genes, leading to the differentiation of a multitude of different retinal cell types. This review examines what is known about each sequential step in retinal specification during normal vertebrate development, and how that knowledge will be important to understand how RSCs might be manipulated for regenerative therapies to treat retinal diseases.
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Affiliation(s)
- Norann A Zaghloul
- Department of Anatomy and Cell Biology, The George Washington University, 2300 Eye Street, NW, Washington, DC 20037, USA
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26
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Zhang X, Serb JM, Greenlee MHW. Mouse retinal development: a dark horse model for systems biology research. Bioinform Biol Insights 2011; 5:99-113. [PMID: 21698072 PMCID: PMC3118678 DOI: 10.4137/bbi.s6930] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The developing retina is an excellent model to study cellular fate determination and differentiation in the context of a complex tissue. Over the last decade, many basic principles and key genes that underlie these processes have been experimentally identified. In this review, we construct network models to summarize known gene interactions that underlie determination and fundamentally affect differentiation of each retinal cell type. These networks can act as a scaffold to assemble subsequent discoveries. In addition, these summary networks provide a rational segue to systems biology approaches necessary to understand the many events leading to appropriate cellular determination and differentiation in the developing retina and other complex tissues.
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Affiliation(s)
- Xia Zhang
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
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27
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Zheng M, Zhang Z, Zhao X, Ding Y, Han H. The Notch signaling pathway in retinal dysplasia and retina vascular homeostasis. J Genet Genomics 2011; 37:573-82. [PMID: 20933211 DOI: 10.1016/s1673-8527(09)60077-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 08/12/2010] [Accepted: 08/18/2010] [Indexed: 01/16/2023]
Abstract
The retina is one of the most essential elements of vision pathway in vertebrate. The dysplasia of retina cause congenital blindness or vision disability in individuals, and the misbalance in adult retinal vascular homeostasis leads to neovascularization-associated diseases in adults, such as diabetic retinopathy or age-related macular degeneration. Many developmental signaling pathways are involved in the process of retinal development and vascular homeostasis. Among them, Notch signaling pathway has long been studied, and Notch signaling-interfered mouse models show both neural retina dysplasia and vascular abnormality. In this review, we discuss the roles of Notch signaling in the maintenance of retinal progenitor cells, specification of retinal neurons and glial cells, and the sustaining of retina vascular homeostasis, especially from the aspects of conditional knockout mouse models. The potential of Notch signal manipulation may provide a powerful cell fate- and neovascularization-controlling tool that could have important applications in treatment of retinal diseases.
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Affiliation(s)
- Minhua Zheng
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
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28
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Zheng MH, Shi M, Pei Z, Gao F, Han H, Ding YQ. The transcription factor RBP-J is essential for retinal cell differentiation and lamination. Mol Brain 2009; 2:38. [PMID: 20017954 PMCID: PMC2804697 DOI: 10.1186/1756-6606-2-38] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 12/18/2009] [Indexed: 11/10/2022] Open
Abstract
Background The highly ordered vertebrate retina is composed of seven cell types derived from a common pool of retinal progenitor cells (RPCs), and is a good model for the studies of cell differentiation and interaction during neural development. Notch signaling plays a pivotal role in retinogenesis in mammals, but the full scope of the functions of Notch pathway, and the underlying molecular mechanisms, remain unclear. Results In this study, we conditionally knocked out RBP-J, the critical transcription factor downstream to all four Notch receptors, in RPCs of mouse retina at different developmental stages. Disruption of RBP-J at early retinogenesis resulted in accelerated RPCs differentiation, but only photoreceptors and ganglion cells were overrepresented, with other neuronal populations diminished. Similarly, deletion of RBP-J at early postnatal days also led to overproduction of photoreceptors, suggesting that RBP-J governed RPCs specification and differentiation through retinogenesis. In all the RBP-J deletion models, the retinal laminar structures were distorted by the formation of numerous rosette-like structures, reminiscent of β-catenin deficient retina. Indeed, we found that these rosettes aligned with gaps in β-catenin expression at the apical surface of the retina. By in vivo electroporation-mediated transfection, we demonstrated that lamination defects in RBP-J deficient retinae were rescued by overexpressing β-catenin. Conclusions Our data indicate that RBP-J-mediated canonical Notch signaling governs retinal cell specification and differentiation, and maintains retinal lamination through the expression of β-catenin.
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Affiliation(s)
- Min-Hua Zheng
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China.
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29
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Nelson BR, Hartman BH, Ray CA, Hayashi T, Bermingham-McDonogh O, Reh TA. Acheate-scute like 1 (Ascl1) is required for normal delta-like (Dll) gene expression and notch signaling during retinal development. Dev Dyn 2009; 238:2163-78. [PMID: 19191219 DOI: 10.1002/dvdy.21848] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Delta gene expression in Drosophila is regulated by proneural basic helix-loop-helix (bHLH) transcription factors, such as acheate-scute. In vertebrates, multiple Delta-like and proneural bHLH genes are expressed during neurogenesis, especially in the retina. We recently uncovered a relationship between Acheate-scute like 1 (Ascl1), Delta-like genes, and Notch in chick retinal progenitors. Here, we report that mammalian retinal progenitors are also the primary source of Delta-like genes, likely signaling through Notch among themselves, while differentiating neurons expressed Jagged2. Ascl1 is coexpressed in Delta-like and Notch active progenitors, and required for normal Delta-like gene expression and Notch signaling. We also reveal a role for Ascl1 in the regulation of Hes6, a proneurogenic factor that inhibits Notch signaling to promote neural rather than glial differentiation. Thus, these results suggest a molecular mechanism whereby attenuated Notch levels coupled with reduced proneurogenic activity in progenitors leads to increased gliogenesis and decreased neurogenesis in the Ascl1-deficient retina.
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Affiliation(s)
- Branden R Nelson
- Department of Biological Structure, School of Medicine, University of Washington, Seattle, Washington 98195, USA.
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30
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Rbpj cell autonomous regulation of retinal ganglion cell and cone photoreceptor fates in the mouse retina. J Neurosci 2009; 29:12865-77. [PMID: 19828801 DOI: 10.1523/jneurosci.3382-09.2009] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Vertebrate retinal progenitor cells (RPCs) are pluripotent, but pass through competence states that progressively restrict their developmental potential (Cepko et al., 1996; Livesey and Cepko, 2001; Cayouette et al., 2006). In the rodent eye, seven retinal cell classes differentiate in overlapping waves, with RGCs, cone photoreceptors, horizontals, and amacrines forming predominantly before birth, and rod photoreceptors, bipolars, and Müller glia differentiating postnatally. Both intrinsic and extrinsic factors regulate each retinal cell type (for review, see Livesey and Cepko, 2001). Here, we conditionally deleted the transcription factor Rbpj, a critical integrator of multiple Notch signals (Jarriault et al., 1995; Honjo, 1996; Kato et al., 1997; Han et al., 2002), during prenatal mouse retinal neurogenesis. Removal of Rbpj caused reduced proliferation, premature neuronal differentiation, apoptosis, and profound mispatterning. To determine the cell autonomous requirements for Rbpj during RGC and cone formation, we marked Cre-generated retinal lineages with GFP expression, which showed that Rbpj autonomously promotes RPC mitotic activity, and suppresses RGC and cone fates. In addition, the progressive loss of Rbpj-/- RPCs resulted in a diminished progenitor pool available for rod photoreceptor formation. This circumstance, along with the overproduction of Rbpj-/- cones, revealed that photoreceptor development is under homeostatic regulation. Finally, to understand how the Notch pathway regulates the simultaneous formation of multiple cell types, we compared the RGC and cone phenotypes of Rbpj to Notch1 (Jadhav et al., 2006b; Yaron et al., 2006), Notch3, and Hes1 mutants. We found particular combinations of Notch pathway genes regulate the development of each retinal cell type.
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31
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Kubo F, Nakagawa S. Hairy1 acts as a node downstream of Wnt signaling to maintain retinal stem cell-like progenitor cells in the chick ciliary marginal zone. Development 2009; 136:1823-33. [DOI: 10.1242/dev.029272] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In the vertebrate retina, stem cell-like progenitor cells are maintained in a distinct region called the ciliary marginal zone (CMZ). Canonical Wnt signaling regulates the maintenance of the progenitor cells in the CMZ. However, its downstream molecular mechanisms have remained largely unclear. Here, we show that chick Hairy1, an established Notch signaling effector,mediates the Wnt-dependent maintenance of CMZ progenitor cells in chicken. Interestingly, unlike other developmental contexts in which Hes gene expression is regulated by Notch signaling, Hairy1 expression in the CMZ is regulated by Wnt signaling. Hairy1 is necessary and sufficient for the expression of a set of molecular markers characteristic of the CMZ, and Wnt2b fails to induce CMZ markers when Hairy1 activity is inhibited. Furthermore,microarray analysis identifies multiple Wnt-responsive transcription factors that activate Hairy1 expression. We thus propose that Hairy1 functions as a node downstream of Wnt signaling to maintain progenitor cells in the chick CMZ.
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Affiliation(s)
- Fumi Kubo
- RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198,Japan
| | - Shinichi Nakagawa
- RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198,Japan
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32
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Muto A, Iida A, Satoh S, Watanabe S. The group E Sox genes Sox8 and Sox9 are regulated by Notch signaling and are required for Müller glial cell development in mouse retina. Exp Eye Res 2009; 89:549-58. [PMID: 19490914 DOI: 10.1016/j.exer.2009.05.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 04/02/2009] [Accepted: 05/21/2009] [Indexed: 12/23/2022]
Abstract
Although Müller glial cells play pivotal roles in the vertebrate retina, the regulation of their development is poorly understood. While Notch-Hes5 signaling has been shown to be involved in this developmental process, the presence of Müller glial cells in Hes5-deficient mice suggests the involvement of other molecules. We found that two group E Sox genes, Sox8 and Sox9, are expressed in proliferating progenitors and then exclusively in Müller glial cells in mouse retina. Knocking-down Sox8 and Sox9 by shRNA significantly reduced the population of Müller glial cells and relatively increased the proportion of rod photoreceptors, suggesting that the Sox genes play roles in the specification of Müller glial cells. Using an activated form of Notch and the gamma-secretase inhibitor DAPT, we also found that Notch signaling regulates the transcription of Sox8 and Sox9. This is the first evidence that group E Sox genes play important roles in the developing vertebrate retina.
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Affiliation(s)
- Akihiko Muto
- Department of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo 108-8639, Japan
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33
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Wall DS, Mears AJ, McNeill B, Mazerolle C, Thurig S, Wang Y, Kageyama R, Wallace VA. Progenitor cell proliferation in the retina is dependent on Notch-independent Sonic hedgehog/Hes1 activity. ACTA ACUST UNITED AC 2009; 184:101-12. [PMID: 19124651 PMCID: PMC2615087 DOI: 10.1083/jcb.200805155] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Sonic hedgehog (Shh) is an indispensable, extrinsic cue that regulates progenitor and stem cell behavior in the developing and adult mammalian central nervous system. Here, we investigate the link between the Shh signaling pathway and Hes1, a classical Notch target. We show that Shh-driven stabilization of Hes1 is independent of Notch signaling and requires the Shh effector Gli2. We identify Gli2 as a primary mediator of this response by showing that Gli2 is required for Hh (Hedgehog)-dependent up-regulation of Hes1. We also show using chromatin immunoprecipitation that Gli2 binds to the Hes1 promoter, which suggests that Hes1 is a Hh-dependent direct target of Gli2 signaling. Finally, we show that Shh stimulation of progenitor proliferation and cell diversification requires Gli2 and Hes1 activity. This paper is the first demonstration of the mechanistic and functional link between Shh, Gli, and Hes1 in the regulation of progenitor cell behavior.
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Affiliation(s)
- Dana S Wall
- Ottawa Health Research Institute, Ottawa, Ontario, Canada
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34
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Nelson BR, Reh TA. Relationship between Delta-like and proneural bHLH genes during chick retinal development. Dev Dyn 2008; 237:1565-80. [PMID: 18435466 DOI: 10.1002/dvdy.21550] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Notch signaling in the retina maintains a pool of progenitor cells throughout retinogenesis. However, two Notch-ligands from the Delta-like gene family, Dll1 and Dll4, are present in the developing retina. To understand their relationship, we characterized Dll1 and Dll4 expression with respect to proliferating progenitor cells and newborn neurons in the chick retina. Dll4 matched the pattern of neural differentiation. By contrast, Dll1 was primarily expressed in progenitor cells. We compared Dll1 and Dll4 kinetic profiles with that of the transiently up-regulated cascade of proneural basic helix-loop-helix (bHLH) genes after synchronized progenitor cell differentiation, which suggested a potential role for Ascl1 in the regulation of Delta-like genes. Gain-of-function assays demonstrate that Ascl1 does influence Delta-like gene expression and Notch signaling activity. These data suggest that multiple sources of Notch signaling from newborn neurons and progenitors themselves coordinate retinal histogenesis.
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Affiliation(s)
- Branden R Nelson
- Department of Biological Structure, School of Medicine, University of Washington, Seattle, Washington 98195, USA.
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35
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Hes1 Regulates Corneal Development and the Function of Corneal Epithelial Stem/Progenitor Cells. Stem Cells 2008; 26:1265-74. [DOI: 10.1634/stemcells.2007-1067] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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36
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Ohsawa R, Kageyama R. Regulation of retinal cell fate specification by multiple transcription factors. Brain Res 2008; 1192:90-8. [PMID: 17488643 DOI: 10.1016/j.brainres.2007.04.014] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 03/26/2007] [Accepted: 04/03/2007] [Indexed: 01/22/2023]
Abstract
Retinal cell fate specification is strictly regulated by multiple transcription factors. Regarding regulation of cell proliferation and differentiation, basic helix-loop-helix (bHLH) type repressors and activators function in an antagonistic manner. Repressor-type bHLH factors maintain retinal progenitor cells, whereas activator-type bHLH factors promote neuronal cell fate determination. However, bHLH genes alone are not sufficient for acquiring proper neuronal subtype identity. Recent findings have shown that retinal cell fate specification is regulated by combinations of bHLH and homeobox genes. It is conceivable that homeobox genes confer positional identity whereas bHLH genes regulate neuronal determination and differentiation. Moreover, it has been shown that bHLH genes implicated in retinal cell fate determination regulate expression of other bHLH genes, implying that there is a complicated transcription network regulating retinal development.
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Affiliation(s)
- Ryosuke Ohsawa
- Institute for Virus Research, Kyoto University, Shogoin-Kawahara, Sakyo-ku, Kyoto 606-8507, Japan
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37
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Wallace VA. Proliferative and cell fate effects of Hedgehog signaling in the vertebrate retina. Brain Res 2008; 1192:61-75. [PMID: 17655833 DOI: 10.1016/j.brainres.2007.06.018] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 05/19/2007] [Accepted: 06/03/2007] [Indexed: 11/26/2022]
Abstract
The retina is an excellent system for delving into the question of how cell fate, number and organization are regulated in the central nervous system. Multipotential progenitor cells in the immature retina proliferate, exit the cell cycle and generate neurons and one glial cell type in a prescribed temporal sequence. While some aspects of progenitor behavior are controlled cell intrinsically, extrinsic signals present in the retina environment have been shown to impact on proliferation, differentiation and cell fate of progenitors. Intercellular signaling proteins of the Hedgehog (Hh) family regulate several aspects of visual system development in vertebrates--ranging from early eye field patterning to retinal and optic nerve development. This review highlights the role of Hh signaling on retinal progenitor proliferation and diversification.
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Affiliation(s)
- Valerie A Wallace
- Molecular Medicine Program, Ottawa Health Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6.
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38
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Sölter M, Locker M, Boy S, Taelman V, Bellefroid EJ, Perron M, Pieler T. Characterization and function of the bHLH-O protein XHes2: insight into the mechanisms controlling retinal cell fate decision. Development 2007; 133:4097-108. [PMID: 17008450 DOI: 10.1242/dev.02567] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neurons and glial cells differentiate from common multipotent precursors in the vertebrate retina. We have identified a novel member of the hairy/Enhancer of split [E(spl)] gene family in Xenopus, XHes2, as a regulator to bias retinal precursor cells towards a glial fate. XHes2 expression is predominantly restricted to sensory organ territories, including the retina. Using in vivo lipofection in the optic vesicle, we found that XHes2 overexpression dramatically increases gliogenesis at the expense of neurogenesis. This increase in glial cells correlates with a delayed cell cycle withdrawal of some retinal progenitors. In addition, birthdating experiments suggest that XHes2 deviates some early born cell types towards a glial fate that would normally have given rise to neurons. Conversely, a significant inhibition of glial differentiation is observed upon XHes2 loss of function. The gliogenic activity of XHes2 relies on its ability to inhibit neuronal differentiation by at least two distinct mechanisms: it not only negatively regulates XNgnr1 and NeuroD transcription, but it also physically interacts with a subset of proneural bHLH proteins.
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Affiliation(s)
- Marion Sölter
- DFG-Center of Molecular Physiology of the Brain, Department of Developmental Biochemistry, University of Goettingen, Justus-von-Liebig-Weg 11, 37077 Goettingen, Germany
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39
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Nelson BR, Hartman BH, Georgi SA, Lan MS, Reh TA. Transient inactivation of Notch signaling synchronizes differentiation of neural progenitor cells. Dev Biol 2007; 304:479-98. [PMID: 17280659 PMCID: PMC1979095 DOI: 10.1016/j.ydbio.2007.01.001] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 12/23/2006] [Accepted: 01/02/2007] [Indexed: 11/19/2022]
Abstract
In the developing nervous system, the balance between proliferation and differentiation is critical to generate the appropriate numbers and types of neurons and glia. Notch signaling maintains the progenitor pool throughout this process. While many components of the Notch pathway have been identified, the downstream molecular events leading to neural differentiation are not well understood. We have taken advantage of a small molecule inhibitor, DAPT, to block Notch activity in retinal progenitor cells, and analyzed the resulting molecular and cellular changes over time. DAPT treatment causes a massive, coordinated differentiation of progenitors that produces cell types appropriate for their developmental stage. Transient exposure of retina to DAPT for specific time periods allowed us to define the period of Notch inactivation that is required for a permanent commitment to differentiate. Inactivation of Notch signaling revealed a cascade of proneural bHLH transcription factor gene expression that correlates with stages in progenitor cell differentiation. Microarray/QPCR analysis confirms the changes in Notch signaling components, and reveals new molecular targets for investigating neuronal differentiation. Thus, transient inactivation of Notch signaling synchronizes progenitor cell differentiation, and allows for a systematic analysis of key steps in this process.
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Affiliation(s)
- Branden R. Nelson
- Department of Biological Structure, University of Washington, Seattle, WA 98195
| | - Byron H. Hartman
- Department of Biological Structure, University of Washington, Seattle, WA 98195
| | - Sean A. Georgi
- Neurobiology and Behavior Program, University of Washington, Seattle, WA 98195
| | - Michael S. Lan
- The Research Institute for Children, Children's Hospital, New Orleans, LA 70118
| | - Thomas A. Reh
- Department of Biological Structure, University of Washington, Seattle, WA 98195
- Neurobiology and Behavior Program, University of Washington, Seattle, WA 98195
- Author for correspondence: Dr. T.A. Reh, Department of Biological Structure, Box 357420, University of Washington, Seattle, WA 98195, , phone 206-543-8043, fax 206-543-1524
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40
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Hashimoto T, Zhang XM, Yi-kuang Chen B, Yang XJ. VEGF activates divergent intracellular signaling components to regulate retinal progenitor cell proliferation and neuronal differentiation. Development 2006; 133:2201-10. [PMID: 16672338 PMCID: PMC7060787 DOI: 10.1242/dev.02385] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
During vertebrate neurogenesis, multiple extracellular signals influence progenitor cell fate choices. The process by which uncommitted progenitor cells interpret and integrate signals is not well understood. We demonstrate here that in the avascular chicken retina, vascular endothelial growth factor (VEGF) secreted by postmitotic neurons acts through the FLK1 receptor present on progenitor cells to influence cell proliferation and commitment. Augmenting VEGF signals increases progenitor cell proliferation and decreases retinal ganglion cell genesis. Conversely, absorbing endogenous VEGF ligand or disrupting FLK1 activity attenuates cell proliferation and enhances retinal ganglion cell production. In addition, we provide evidence that VEGF signals transmitted by the FLK1 receptor activate divergent intracellular signaling components, which regulate different responses of progenitor cells. VEGF-induced proliferation is influenced by the MEK-ERK pathway, as well as by the basic helix-loop-helix factor HES1. By contrast, VEGF-dependent ganglion cell suppression does not require MEK-ERK activation, but instead relies on VEGF-stimulated HES1 activity, which is independent of NOTCH signaling. Moreover, elevated HES1 expression promotes progenitor cell proliferation and prevents overproduction of retinal ganglion cells owing to the loss of VEGF or sonic hedgehog (SHH), another signal that suppresses ganglion cell development. Based on previous and current findings, we propose that HES1 serves as a convergent signaling node within early retinal progenitor cells to integrate various cell-extrinsic cues, including VEGF and SHH, in order to control cell proliferation and neuronal specification.
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Affiliation(s)
- Takao Hashimoto
- Jules Stein Eye Institute and Department of Ophthalmology, Molecular Biology Institute, University of California, David Geffen School of Medicine, 100 Stein Plaza Los Angeles, CA 90095, USA
| | - Xiang-Mei Zhang
- Jules Stein Eye Institute and Department of Ophthalmology, Molecular Biology Institute, University of California, David Geffen School of Medicine, 100 Stein Plaza Los Angeles, CA 90095, USA
| | | | - Xian-Jie Yang
- Jules Stein Eye Institute and Department of Ophthalmology, Molecular Biology Institute, University of California, David Geffen School of Medicine, 100 Stein Plaza Los Angeles, CA 90095, USA
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41
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Nelson BR, Gumuscu B, Hartman BH, Reh TA. Notch activity is downregulated just prior to retinal ganglion cell differentiation. Dev Neurosci 2006; 28:128-41. [PMID: 16508310 DOI: 10.1159/000090759] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Accepted: 04/12/2005] [Indexed: 11/19/2022] Open
Abstract
The Notch signaling pathway is important at several stages of retinal development including the differentiation of retinal ganglion cells and Muller glia. The downstream effectors of Notch signaling, Hes1 and Hes5, have been shown to be critical in the retina as well. While Notch activity directly regulates Hes1 and Hes5 elsewhere in the nervous system, it has been unclear whether Hes1 and/or Hes5 are directly regulated by Notch activity in the developing retina. Here, we report that both Hes1 and Hes5 are directly regulated by Notch activity during retinal development. Using fluorescence-based Hes1 and Hes5 reporter constructs, we can monitor Notch activity in progenitor cells in the intact retina, and we find that Notch activity is downregulated just prior to retinal ganglion cell differentiation.
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Affiliation(s)
- Branden R Nelson
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
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42
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Jadhav AP, Mason HA, Cepko CL. Notch 1 inhibits photoreceptor production in the developing mammalian retina. Development 2006; 133:913-23. [PMID: 16452096 DOI: 10.1242/dev.02245] [Citation(s) in RCA: 173] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The transmembrane receptor Notch1 plays a role in development and homeostasis in vertebrates and invertebrates. The mammalian retina is an excellent tissue in which to dissect the precise role of Notch signaling in regulating cell fate and proliferation. However, a systematic analysis has been limited by the early embryonic lethality of Notch1-null mice. Here, Notch1 was conditionally removed from the murine retina either early or late in development. Removal of Notch1 early led to a reduction in the size of the retina as well as aberrant morphology. A decrease in the number of progenitor cells and premature neurogenesis accounted for the reduction in size. Unexpectedly, ablation of Notch1 in early progenitor cells led to enhanced cone photoreceptor production, and ablation of Notch1 at later points led to an almost exclusive production of rod photoreceptor cells. These data suggest that Notch1 not only maintains the progenitor state, but is required to inhibit the photoreceptor fate. These cone enriched mutant mice should prove to be a valuable resource for the study of this relatively rare mammalian photoreceptor cell type.
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Affiliation(s)
- Ashutosh P Jadhav
- Department of Genetics and Howard Hughes Medical Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
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Wang Y, Dakubo GD, Thurig S, Mazerolle CJ, Wallace VA. Retinal ganglion cell-derived sonic hedgehog locally controls proliferation and the timing of RGC development in the embryonic mouse retina. Development 2005; 132:5103-13. [PMID: 16236765 DOI: 10.1242/dev.02096] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The timing of cell cycle exit and temporal changes in the developmental competence of precursor cells are key components for the establishment of the normal complement of cell types in the mammalian retina. The identity of cell extrinsic cues that control these processes is largely unknown. We showed previously in mouse retina that sonic hedgehog (Shh) signalling from retinal ganglion cells (RGCs) to retinal precursor cells (RPC) is required for the establishment of normal retinal organization. Here, we show that conditional ablation of Shh expression in the peripheral mouse results in a depletion of the RPC pool, owing to precocious cell-cycle exit and neuronal differentiation. These changes were correlated with the downregulation of cyclin D1 and Hes1 gene expression. Shh inactivation also results in an increase in RGC number owing to a bias of RPC towards RGC production. In contrast to zebrafish, where Shh signalling drives cell cycle exit and RGC development, our findings indicate that in the mouse retina Shh signalling is required to maintain RPC proliferation and to control the timing of RGC development.
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Affiliation(s)
- Yaping Wang
- Molecular Medicine Program, Ottawa Health Research Institute and University of Ottawa Eye Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada
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Matter-Sadzinski L, Puzianowska-Kuznicka M, Hernandez J, Ballivet M, Matter JM. A bHLH transcriptional network regulating the specification of retinal ganglion cells. Development 2005; 132:3907-21. [PMID: 16079155 DOI: 10.1242/dev.01960] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In the developing retina, the production of ganglion cells is dependent on the proneural proteins NGN2 and ATH5, whose activities define stages along the pathway converting progenitors into newborn neurons. Crossregulatory interactions between NGN2, ATH5 and HES1 maintain the uncommitted status of ATH5-expressing cells during progenitor patterning, and later on regulate the transition from competence to cell fate commitment. Prior to exiting the cell cycle, a subset of progenitors is selected from the pool of ATH5-expressing cells to go through a crucial step in the acquisition of a definitive retinal ganglion cell fate. The selected cells are those in which the upregulation of NGN2, the downregulation of HES1 and the autostimulation of ATH5 are coordinated with the progression of progenitors through the last cell cycle. This coordinated pattern initiates the transcription of ganglion cell-specific traits and determines the size of the ganglion cell population.
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Affiliation(s)
- Lidia Matter-Sadzinski
- University of Lausanne, Eye Hospital Jules Gonin and Institute for Research in Ophthalmology, 15 avenue de France, 1004 Lausanne, Switzerland
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Lee HY, Wroblewski E, Philips GT, Stair CN, Conley K, Reedy M, Mastick GS, Brown NL. Multiple requirements for Hes 1 during early eye formation. Dev Biol 2005; 284:464-78. [PMID: 16038893 PMCID: PMC4128414 DOI: 10.1016/j.ydbio.2005.06.010] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Revised: 05/29/2005] [Accepted: 06/06/2005] [Indexed: 10/25/2022]
Abstract
During embryogenesis, multiple developmental processes are integrated through their precise temporal regulation. Hes1 is a transcriptional repressor that regulates the timing of mammalian retinal neurogenesis. However, roles for Hes1 in early eye development have not been well defined. Here, we show that Hes1 is expressed in the forming lens, optic vesicle, cup, and pigmented epithelium and is necessary for proper growth, morphogenesis, and differentiation of these tissues. Because Hes1 is required throughout the eye, we investigated its interaction with Pax6. Hes1-Pax6 double mutant embryos are eyeless suggesting these genes are coordinately required for initial morphogenesis and outgrowth of the optic vesicle. In Hes1 mutants, Math5 expression is precocious along with retinal ganglion cell, amacrine, and horizontal neuron formation. In contrast to apparent cooperativity between Pax6 and Hes1 during morphogenesis, each gene regulates Math5 and RGC genesis independently. Together, these studies demonstrate that Hes1, like Pax6, simultaneously regulates multiple developmental processes during optic development.
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Affiliation(s)
- Hae Young Lee
- Department of Pediatrics, Northwestern University Medical School at Children’s Memorial Institute for Education and Research, Chicago, IL 60614, USA
| | - Emily Wroblewski
- Department of Pediatrics, Northwestern University Medical School at Children’s Memorial Institute for Education and Research, Chicago, IL 60614, USA
| | - Gary T. Philips
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Carrie N. Stair
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Kevin Conley
- Divisions of Developmental Biology and Ophthalmology, Children’s Hospital Research Foundation, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati Medical School, Cincinnati, OH 45229, USA
| | - Meredith Reedy
- Divisions of Developmental Biology and Ophthalmology, Children’s Hospital Research Foundation, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati Medical School, Cincinnati, OH 45229, USA
| | - Grant S. Mastick
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Nadean L. Brown
- Department of Pediatrics, Northwestern University Medical School at Children’s Memorial Institute for Education and Research, Chicago, IL 60614, USA
- Divisions of Developmental Biology and Ophthalmology, Children’s Hospital Research Foundation, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati Medical School, Cincinnati, OH 45229, USA
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Bernardos RL, Lentz SI, Wolfe MS, Raymond PA. Notch-Delta signaling is required for spatial patterning and Müller glia differentiation in the zebrafish retina. Dev Biol 2005; 278:381-95. [PMID: 15680358 DOI: 10.1016/j.ydbio.2004.11.018] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Revised: 11/11/2004] [Accepted: 11/12/2004] [Indexed: 10/26/2022]
Abstract
Notch-Delta signaling has been implicated in several alternative modes of function in the vertebrate retina. To further investigate these functions, we examined retinas from zebrafish embryos in which bidirectional Notch-Delta signaling was inactivated either by the mind bomb (mib) mutation, which disrupts E3 ubiquitin ligase activity, or by treatment with gamma-secretase inhibitors, which prevent intramembrane proteolysis of Notch and Delta. We found that inactivating Notch-Delta signaling did not prevent differentiation of retinal neurons, but it did disrupt spatial patterning in both the apical-basal and planar dimensions of the retinal epithelium. Retinal neurons differentiated, but their laminar arrangement was disrupted. Photoreceptor differentiation was initiated normally, but its progression was slowed. Although confined to the apical retinal surface as in normal retinas, the planar organization of cone photoreceptors was disrupted: cones of the same spectral subtype were clumped rather than regularly spaced. In contrast to neurons, Müller glia failed to differentiate suggesting an instructive role for Notch-Delta signaling in gliogenesis.
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Affiliation(s)
- R L Bernardos
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109-0616, USA
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Yi X, Schubert M, Peachey NS, Suzuma K, Burks DJ, Kushner JA, Suzuma I, Cahill C, Flint CL, Dow MA, Leshan RL, King GL, White MF. Insulin receptor substrate 2 is essential for maturation and survival of photoreceptor cells. J Neurosci 2005; 25:1240-8. [PMID: 15689562 PMCID: PMC6725974 DOI: 10.1523/jneurosci.3664-04.2005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2004] [Revised: 12/07/2004] [Accepted: 12/09/2004] [Indexed: 02/02/2023] Open
Abstract
Insulin receptor substrates (Irs-proteins) integrate signals from the insulin and insulin-like growth factor-1 (IGF1) receptors with other processes to control cellular growth, function, and survival. Here, we show that Irs2 promoted the maturation and survival of photoreceptors in the murine retina immediately after birth. Irs2 was mainly localized to the outer plexiform layer as well as to photoreceptor inner segments. It was also seen in ganglion cells and inner plexiform layer but in smaller amounts. Compared with control littermates, Irs2 knock-out mice lose 10% of their photoreceptors 1 week after birth and up to 50% by 2 weeks of age as a result of increased apoptosis. The surviving photoreceptor cells developed short organized segments, which displayed proportionally diminished but otherwise normal electrical function. However, IGF1-stimulated Akt phosphorylation was barely detected, and cleaved/activated caspase-3 was significantly elevated in isolated retinas of Irs2-/- mice. When diabetes was prevented, which allowed the Irs2-/- mice to survive for 2 years, most photoreceptor cells were lost by 16 months of age. Because apoptosis is the final common pathway in photoreceptor degeneration, pharmacological strategies that increase Irs2 expression or function in photoreceptor cells could be a general treatment for blinding diseases such as retinitis pigmentosa.
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Affiliation(s)
- Xianjin Yi
- Howard Hughes Medical Institute, Children's Hospital Boston, Boston, Massachusetts 02115, USA
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Kodama Y, Hijikata M, Kageyama R, Shimotohno K, Chiba T. The role of notch signaling in the development of intrahepatic bile ducts. Gastroenterology 2004; 127:1775-86. [PMID: 15578515 DOI: 10.1053/j.gastro.2004.09.004] [Citation(s) in RCA: 191] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Mutations in Jagged1 , a Notch ligand, cause Alagille syndrome (AGS), a disorder characterized by a paucity of intrahepatic bile ducts (IHBD). The mechanism underlying the contribution of the Notch signaling pathway to IHBD formation, however, remains unknown. Here we investigated the role of Notch signaling in IHBD development. METHODS The expression patterns of Jagged1, Notch2, and Hes1 during mouse liver development were analyzed by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR), immunoblot, and immunohistochemistry. The hepatocyte maturation level and IHBD development were studied in Hes1 null mice in comparison with wild-type mice. The effect of Jagged1 on biliary differentiation was assessed by using an in vitro 2-cell coculture system with WB-F344 cells, a cell line derived from normal adult rat liver. RESULTS Jagged1 was expressed in the portal mesenchyme during the neonatal period. During the same period, Notch2 and Hes1 expression was observed in the biliary epithelial cells adjacent to the Jagged1-positive cells. During ductal plate remodeling, Notch2 and Hes1 were up-regulated exclusively in the biliary epithelial cells that form tubular structures. In contrast, the tubular formation of IHBD was completely absent in Hes1 null mice. Coculture with Balb3T3 cells stably overexpressing Jagged1 induced transactivation of the Hes1 promoter and increased expression of biliary lineage markers, such as cytokeratin-19 and gamma-glutamyl transpeptidase, in WB-F344 cells. CONCLUSIONS Our results suggest that Notch signaling has an important role in the differentiation of biliary epithelial cells and is essential for their tubular formation during IHBD development.
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Affiliation(s)
- Yuzo Kodama
- Department of Gastroenterology and Hepatology, Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan
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