1
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Krueger LA, Bills JD, Lim ZY, Skidmore JM, Martin DM, Morris AC. Chromatin remodeler Chd7 regulates photoreceptor development and outer segment length. Exp Eye Res 2023; 226:109299. [PMID: 36343670 PMCID: PMC10354686 DOI: 10.1016/j.exer.2022.109299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/29/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022]
Abstract
Mutations in the chromatin remodeling factor CHD7 are the predominant cause of CHARGE syndrome, a congenital disorder that frequently includes ocular coloboma. Although CHD7 is known to be required for proper ocular morphogenesis, its role in retinal development has not been thoroughly investigated. Given that individuals with CHARGE syndrome can experience visual impairment even in the absence of coloboma, a better understanding of CHD7 function in the retina is needed. In this study, we characterized the expression pattern of Chd7 in the developing zebrafish and mouse retina and documented ocular and retinal phenotypes in Chd7 loss-of-function mutants. Zebrafish Chd7 was expressed throughout the retinal neuroepithelium when retinal progenitor cells were actively proliferating, and later in subsets of newly post-mitotic retinal cells. At stages of retinal development when most retinal cell types had terminally differentiated, Chd7 expression remained strong in the ganglion cell layer and in some cells in the inner nuclear layer. Intriguingly, strong expression of Chd7 was also observed in the outer nuclear layer where it was co-expressed with markers of post-mitotic cone and rod photoreceptors. Expression of mouse CHD7 displayed a similar pattern, including expression in the ganglion cells, subsets of inner nuclear layer cells, and in the distal outer nuclear layer as late as P15. Two different mutant chd7 zebrafish lines were characterized for ocular and retinal defects. These mutants displayed microphthalmia, reduced numbers of cone photoreceptors, and truncated rod and cone photoreceptor outer segments. Reduced cone photoreceptor number and abnormal outer segments were also observed in heterozygous Chd7 mutant mice. Taken together, our results in zebrafish and mouse reveal a conserved, previously undescribed role for Chd7 in retinal development and photoreceptor outer segment morphogenesis. Moreover, our work suggests an avenue of future investigation into the pathogenesis of visual system defects in CHARGE syndrome.
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Affiliation(s)
- Laura A Krueger
- Department of Biology, University of Kentucky, Lexington, KY, 40506-0225, USA
| | - Jessica D Bills
- Department of Biology, University of Kentucky, Lexington, KY, 40506-0225, USA
| | - Zun Yi Lim
- Department of Biology, University of Kentucky, Lexington, KY, 40506-0225, USA
| | | | - Donna M Martin
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA; Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Ann C Morris
- Department of Biology, University of Kentucky, Lexington, KY, 40506-0225, USA.
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2
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Leinonen H, Fu Z, Bull E. Neural and Müller glial adaptation of the retina to photoreceptor degeneration. Neural Regen Res 2023; 18:701-707. [DOI: 10.4103/1673-5374.354511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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3
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Insm1 promotes differentiation of retinal progenitor cells toward photoreceptor cells in the developing retina through up-regulation of SHH. J Mol Histol 2022; 53:947-954. [PMID: 36260151 DOI: 10.1007/s10735-022-10103-8] [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: 04/24/2022] [Accepted: 09/10/2022] [Indexed: 10/24/2022]
Abstract
This article investigated the effect of Insm1 on RPC differentiation in mice and the underlying mechanism. The retinal tissues of mouse embryo at 12.5 days (E12.5) and postnatal 14 days (P14) were collected, following by the detection of Insm1 and corresponding markers by immunofluorescent staining. RPCs isolated from retinal tissues at P1 were cultured in culture medium for 7 days. The differentiation of photoreceptor and glial cells was assessed after RPCs transferred to the differentiation medium for 20 days. Next, the effect of Insm1 overexpression on the differentiation of RPCs toward rod photoreceptor and glial cells were assessed. Insm1 was highly expressed in RPCs of retinal tissues and decline in photoreceptor cells, while hardly expressed in glial cells. Based on the results of Pax-6 positive immunofluorescent staining and flow cytometry detection, RPCs were successfully isolated from retinal tissues. After the culture in differentiation medium, RPCs showed positive staining of Rhodopsin and glial fibrillary acidic protein (GFAP). Further results showed that overexpression of Insm1 significantly increased the percentage of Rhodopsin positive cells, and up-regulated Sonic Hedgehog (SHH), hairy and enhancer of split homolog-1(Hes1), S-opsin and Rhodopsin levels, while decreased the percentage of Glutamine synthetase positive cells, and reduced Glutamine synthetase and GFAP levels. Whereas, the effect of Insm1 overexpression on these protein levels were partly abolished by the knockdown of SHH or Hes1. We conclude that Insm1 promotes the differentiation of RPCs into photoreceptor cells in the developing retina through up-regulation of SHH.
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4
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Krueger LA, Morris AC. Generation of a zebrafish knock-in line expressing MYC-tagged Sox11a using CRISPR/Cas9 genome editing. Biochem Biophys Res Commun 2022; 608:8-13. [DOI: 10.1016/j.bbrc.2022.03.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 11/02/2022]
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5
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Kramer AC, Gurdziel K, Thummel R. A Comparative Analysis of Gene and Protein Expression Throughout a Full 28-Day Retinal Regeneration Time-Course in Adult Zebrafish. Front Cell Dev Biol 2021; 9:741514. [PMID: 34790663 PMCID: PMC8591265 DOI: 10.3389/fcell.2021.741514] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022] Open
Abstract
Following photoreceptors ablation by intense light exposure, adult zebrafish are capable of complete regeneration due to the ability of their Müller glia (MG) to re-enter the cell cycle, creating progenitors that differentiate into new photoreceptors. The majority of previous reports on retinal regeneration focused on the first few days of the regenerative response, which include MG cell-cycle re-entry and progenitor cell proliferation. With this study, we analyzed the full 28-day time-course of regeneration by pairing a detailed morphological/immunological analysis with RNA-seq transcriptional profiling at 8 key time points during retinal regeneration. We observed several novel findings. First, we provide evidence for two separate peaks of MG gliosis, with the secondary gliotic peak occurring after MG cell-cycle re-entry. Second, we highlight a distinct transcriptional shift between 5- and 10-days post lesion that highlights the transition from progenitor proliferation to differentiation into new photoreceptors. Third, we show distinctly different patterns of transcriptional recovery of the photoreceptor opsins at 28 days post lesion. Finally, using differential gene expression analysis, we revealed that the established functional recovery of the retina at 28 days post lesion does not, in fact, return to an undamaged transcriptional state, potentially redefining what the field considers complete regeneration. Together, to our knowledge, this work represents the first histological and transcriptomic map of a 28-day time-course of retinal regeneration in adult zebrafish.
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Affiliation(s)
- Ashley C Kramer
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Katherine Gurdziel
- Genome Sciences Core, Wayne State University, Detroit, MI, United States
| | - Ryan Thummel
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, United States
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6
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Lyu P, Hoang T, Santiago CP, Thomas ED, Timms AE, Appel H, Gimmen M, Le N, Jiang L, Kim DW, Chen S, Espinoza DF, Telger AE, Weir K, Clark BS, Cherry TJ, Qian J, Blackshaw S. Gene regulatory networks controlling temporal patterning, neurogenesis, and cell-fate specification in mammalian retina. Cell Rep 2021; 37:109994. [PMID: 34788628 PMCID: PMC8642835 DOI: 10.1016/j.celrep.2021.109994] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/30/2021] [Accepted: 10/21/2021] [Indexed: 12/30/2022] Open
Abstract
Gene regulatory networks (GRNs), consisting of transcription factors and their target sites, control neurogenesis and cell-fate specification in the developing central nervous system. In this study, we use integrated single-cell RNA and single-cell ATAC sequencing (scATAC-seq) analysis in developing mouse and human retina to identify multiple interconnected, evolutionarily conserved GRNs composed of cell-type-specific transcription factors that both activate genes within their own network and inhibit genes in other networks. These GRNs control temporal patterning in primary progenitors, regulate transition from primary to neurogenic progenitors, and drive specification of each major retinal cell type. We confirm that NFI transcription factors selectively activate expression of genes promoting late-stage temporal identity in primary retinal progenitors and identify other transcription factors that regulate rod photoreceptor specification in postnatal retina. This study inventories cis- and trans-acting factors that control retinal development and can guide cell-based therapies aimed at replacing retinal neurons lost to disease.
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Affiliation(s)
- Pin Lyu
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Thanh Hoang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Clayton P Santiago
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Eric D Thomas
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Andrew E Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Haley Appel
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Megan Gimmen
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nguyet Le
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lizhi Jiang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Dong Won Kim
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Siqi Chen
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - David F Espinoza
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ariel E Telger
- Department of Ophthalmology and Visual Sciences, Brotman Baty Institute, Seattle, WA 98195, USA
| | - Kurt Weir
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Brian S Clark
- Department of Ophthalmology and Visual Sciences, Brotman Baty Institute, Seattle, WA 98195, USA; Brotman Baty Institute, Seattle, WA 98195, USA; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Timothy J Cherry
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101, USA; Brotman Baty Institute, Seattle, WA 98195, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Jiang Qian
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Seth Blackshaw
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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7
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Almeida MP, Welker JM, Siddiqui S, Luiken J, Ekker SC, Clark KJ, Essner JJ, McGrail M. Endogenous zebrafish proneural Cre drivers generated by CRISPR/Cas9 short homology directed targeted integration. Sci Rep 2021; 11:1732. [PMID: 33462297 PMCID: PMC7813866 DOI: 10.1038/s41598-021-81239-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 01/04/2021] [Indexed: 01/04/2023] Open
Abstract
We previously reported efficient precision targeted integration of reporter DNA in zebrafish and human cells using CRISPR/Cas9 and short regions of homology. Here, we apply this strategy to isolate zebrafish Cre recombinase drivers whose spatial and temporal restricted expression mimics endogenous genes. A 2A-Cre recombinase transgene with 48 bp homology arms was targeted into proneural genes ascl1b, olig2 and neurod1. We observed high rates of germline transmission ranging from 10 to 100% (2/20 olig2; 1/5 neurod1; 3/3 ascl1b). The transgenic lines Tg(ascl1b-2A-Cre)is75, Tg(olig2-2A-Cre)is76, and Tg(neurod1-2A-Cre)is77 expressed functional Cre recombinase in the expected proneural cell populations. Somatic targeting of 2A-CreERT2 into neurod1 resulted in tamoxifen responsive recombination in the nervous system. The results demonstrate Cre recombinase expression is driven by the native promoter and regulatory elements of the targeted genes. This approach provides a straightforward, efficient, and cost-effective method to generate cell type specific zebrafish Cre and CreERT2 drivers, overcoming challenges associated with promoter-BAC and transposon mediated transgenics.
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Affiliation(s)
- Maira P Almeida
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.,Genetics and Genomics Interdepartmental Graduate Program, Iowa State University, Ames, IA, USA
| | - Jordan M Welker
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.,Genetics and Genomics Interdepartmental Graduate Program, Iowa State University, Ames, IA, USA.,Department III - Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Sahiba Siddiqui
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.,Genetics and Genomics Interdepartmental Graduate Program, Iowa State University, Ames, IA, USA
| | - Jon Luiken
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Stephen C Ekker
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Karl J Clark
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Jeffrey J Essner
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.,Genetics and Genomics Interdepartmental Graduate Program, Iowa State University, Ames, IA, USA
| | - Maura McGrail
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA. .,Genetics and Genomics Interdepartmental Graduate Program, Iowa State University, Ames, IA, USA.
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8
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Lu J, Liu R, Miao A, Chen X, Xiao W, Wang Y, Cao D, Pan J, Li L, Luo Y. The role of cldnh during the early retinal development in zebrafish. Exp Eye Res 2020; 200:108207. [PMID: 32866532 DOI: 10.1016/j.exer.2020.108207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 08/08/2020] [Accepted: 08/26/2020] [Indexed: 10/23/2022]
Abstract
Claudin-3, an integral component of tight junction, has recently been shown to be expressed in retinal ganglion cells, retinal pigment cells, and retinal vascular endothelial cells. However, the role of claudin-3 in the development of the neural retina and its vessels remains undefined. This study aimed to investigate the role of zebrafish claudin-h (cldnh), the closest ortholog of mouse and human claudin-3, in the development of the neural retina and its vessels. Cldnh levels in green fluorescent protein transgenic zebrafish were genetically manipulated by cldnh morpholino oligonucleotide (MO) and cldnh mRNA to investigate gene function. The expression of cldnh was analyzed using polymerase chain reaction and immunofluorescence staining. The altered morphological, cellular and molecular events in the cldnh MO-morphant eyes were detected using hematoxylin-eosin staining, fluorescent dye injection, confocal in vivo imaging, BrdU labeling, TUNEL assay, RNA sequencing, and Western blot. We demonstrated that the cldnh protein was expressed in the neural retina and the hyaloid vessel which is the predecessor of the retinal vessel in zebrafish. Cldnh knockdown delayed lamination of the neural retina and reduced its thickness, which might be associated with the downregulation of the retinal development-related genes of atoh7, pcdh17, crx, neurod1, insm1a, sox9b and cdh11, and the upregulation of the cell cycle and apoptosis-associated genes of tp53, cdkn1a and casp8. Cldnh knockdown also reduced the density and interrupted the lumenization of the hyaloid vessels, which might be owing to the downregulation of the vessel formation-related genes of hlx1 and myl7. In conclusion, cldnh was required for the normal development of the neural retina and its vessels in zebrafish, providing a basis for elucidating its role in the pathogenesis of retinal vascular or inflammatory diseases.
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Affiliation(s)
- Jing Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Ruyuan Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Aiwen Miao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xiaoyun Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Wei Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Yishen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Di Cao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Jianying Pan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Lisha Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Yan Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China.
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9
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Her9/Hes4 is required for retinal photoreceptor development, maintenance, and survival. Sci Rep 2020; 10:11316. [PMID: 32647335 PMCID: PMC7347560 DOI: 10.1038/s41598-020-68172-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/11/2020] [Indexed: 11/13/2022] Open
Abstract
The intrinsic and extrinsic factors that regulate vertebrate photoreceptor specification and differentiation are complex, and our understanding of all the players is far from complete. Her9, the zebrafish ortholog of human HES4, is a basic helix-loop-helix-orange transcriptional repressor that regulates neurogenesis in several developmental contexts. We have previously shown that her9 is upregulated during chronic rod photoreceptor degeneration and regeneration in adult zebrafish, but little is known about the role of her9 during retinal development. To better understand the function of Her9 in the retina, we generated zebrafish her9 CRISPR mutants. Her9 homozygous mutants displayed striking retinal phenotypes, including decreased numbers of rods and red/green cones, whereas blue and UV cones were relatively unaffected. The reduction in rods and red/green cones correlated with defects in photoreceptor subtype lineage specification. The remaining rods and double cones displayed abnormal outer segments, and elevated levels of apoptosis. In addition to the photoreceptor defects, her9 mutants also possessed a reduced proliferative ciliary marginal zone, and decreased and disorganized Müller glia. Mutation of her9 was larval lethal, with no mutants surviving past 13 days post fertilization. Our results reveal a previously undescribed role for Her9/Hes4 in photoreceptor differentiation, maintenance, and survival.
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10
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Bravo González‐Blas C, Quan X, Duran‐Romaña R, Taskiran II, Koldere D, Davie K, Christiaens V, Makhzami S, Hulselmans G, de Waegeneer M, Mauduit D, Poovathingal S, Aibar S, Aerts S. Identification of genomic enhancers through spatial integration of single-cell transcriptomics and epigenomics. Mol Syst Biol 2020; 16:e9438. [PMID: 32431014 PMCID: PMC7237818 DOI: 10.15252/msb.20209438] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 01/02/2023] Open
Abstract
Single-cell technologies allow measuring chromatin accessibility and gene expression in each cell, but jointly utilizing both layers to map bona fide gene regulatory networks and enhancers remains challenging. Here, we generate independent single-cell RNA-seq and single-cell ATAC-seq atlases of the Drosophila eye-antennal disc and spatially integrate the data into a virtual latent space that mimics the organization of the 2D tissue using ScoMAP (Single-Cell Omics Mapping into spatial Axes using Pseudotime ordering). To validate spatially predicted enhancers, we use a large collection of enhancer-reporter lines and identify ~ 85% of enhancers in which chromatin accessibility and enhancer activity are coupled. Next, we infer enhancer-to-gene relationships in the virtual space, finding that genes are mostly regulated by multiple, often redundant, enhancers. Exploiting cell type-specific enhancers, we deconvolute cell type-specific effects of bulk-derived chromatin accessibility QTLs. Finally, we discover that Prospero drives neuronal differentiation through the binding of a GGG motif. In summary, we provide a comprehensive spatial characterization of gene regulation in a 2D tissue.
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Affiliation(s)
| | - Xiao‐Jiang Quan
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
| | | | - Ibrahim Ihsan Taskiran
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
| | - Duygu Koldere
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
| | | | - Valerie Christiaens
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
| | - Samira Makhzami
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
| | - Gert Hulselmans
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
| | - Maxime de Waegeneer
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
| | - David Mauduit
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
| | | | - Sara Aibar
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
| | - Stein Aerts
- VIB Center for Brain & Disease ResearchLeuvenBelgium
- Department of Human GeneticsKU LeuvenLeuvenBelgium
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11
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Yu S, He J. Stochastic cell-cycle entry and cell-state-dependent fate outputs of injury-reactivated tectal radial glia in zebrafish. eLife 2019; 8:48660. [PMID: 31442201 PMCID: PMC6707787 DOI: 10.7554/elife.48660] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/02/2019] [Indexed: 12/22/2022] Open
Abstract
Gliosis defined as reactive changes of resident glia is the primary response of the central nervous system (CNS) to trauma. The proliferation and fate controls of injury-reactivated glia are essential but remain largely unexplored. In zebrafish optic tectum, we found that stab injury drove a subset of radial glia (RG) into the cell cycle, and surprisingly, proliferative RG responding to sequential injuries of the same site were distinct but overlapping, which was in agreement with stochastic cell-cycle entry. Single-cell RNA sequencing analysis and functional assays further revealed the involvement of Notch/Delta lateral inhibition in this stochastic cell-cycle entry. Furthermore, the long-term clonal analysis showed that proliferative RG were largely gliogenic. Notch inhibition of reactive RG, not dormant and proliferative RG, resulted in an increased production of neurons, which were short-lived. Our findings gain new insights into the proliferation and fate controls of injury-reactivated CNS glia in zebrafish. The brain contains networks of cells known as neurons that rapidly relay information from one place to another. Other brain cells called glial cells perform several roles to support and protect the neurons including holding them in position and supplying them with oxygen and other nutrients. Damage to the brain as a result of physical injuries is one of the leading causes of death and disability in people worldwide. Brain injuries generally stimulate glial cells to enter a “reactive” state to help repair the damage. However, some glial cells may start to divide and produce more glial cells instead, leading to scar-like structures in the brain that hinder the repair process. To investigate why brain injuries trigger some glial cells to divide, Yu and He systematically examined glial cells in the part of the zebrafish brain that handles vision, known as the optic tectum. The experiments showed that a physical injury stimulated some of the glial cells to divide. Repeated injuries to the same part of the brain did not always stimulate the same glial cells to divide, suggesting that this process happens in random cells. Further experiments revealed that molecules involved in a signaling pathway known as Notch signaling were released from some brain cells and inhibited neighboring glial cells from dividing to make new glial cells. Unexpectedly, inhibiting Notch signaling after a brain injury caused some of the glial cells that were in the reactive state to divide to produce neurons instead of glial cells. Understanding how the brain responds to injury may help researchers develop new therapies that may benefit human patients in future. The next steps following on from this work will be to find out whether glial cells in humans and other mammals work in the same way as glial cells in zebrafish.
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Affiliation(s)
- Shuguang Yu
- State Key Laboratory of Neuroscience, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jie He
- State Key Laboratory of Neuroscience, Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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12
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Redox Signaling via Lipid Peroxidation Regulates Retinal Progenitor Cell Differentiation. Dev Cell 2019; 50:73-89.e6. [DOI: 10.1016/j.devcel.2019.05.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 02/07/2019] [Accepted: 05/03/2019] [Indexed: 12/31/2022]
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13
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Taylor SM, Giuffre E, Moseley P, Hitchcock PF. The MicroRNA, miR-18a, Regulates NeuroD and Photoreceptor Differentiation in the Retina of Zebrafish. Dev Neurobiol 2019; 79:202-219. [PMID: 30615274 PMCID: PMC6351175 DOI: 10.1002/dneu.22666] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 12/21/2022]
Abstract
During embryonic retinal development, six types of retinal neurons are generated from multipotent progenitors in a strict spatiotemporal pattern. This pattern requires cell cycle exit (i.e. neurogenesis) and differentiation to be precisely regulated in a lineage‐specific manner. In zebrafish, the bHLH transcription factor NeuroD governs photoreceptor genesis through Notch signaling but also governs photoreceptor differentiation though distinct mechanisms that are currently unknown. Also unknown are the mechanisms that regulate NeuroD and the spatiotemporal pattern of photoreceptor development. Members of the miR‐17‐92 microRNA cluster regulate CNS neurogenesis, and a member of this cluster, miR‐18a, is predicted to target neuroD mRNA. The purpose of this study was to determine if, in the developing zebrafish retina, miR‐18a regulates NeuroD and if it plays a role in photoreceptor development. Quantitative RT‐PCR showed that, of the three miR‐18 family members (miR‐18a, b, and c), miR‐18a expression most closely parallels neuroD expression. Morpholino oligonucleotides and CRISPR/Cas9 gene editing were used for miR‐18a loss‐of‐function (LOF) and both resulted in larvae with more mature photoreceptors at 70 hpf without affecting cell proliferation. Western blot showed that miR‐18a LOF increases NeuroD protein levels and in vitro dual luciferase assay showed that miR‐18a directly interacts with the 3′ UTR of neuroD. Finally, tgif1 mutants have increased miR‐18a expression, less NeuroD protein and fewer mature photoreceptors, and the photoreceptor deficiency is rescued by miR‐18a knockdown. Together, these results show that, independent of neurogenesis, miR‐18a regulates the timing of photoreceptor differentiation and indicate that this occurs through post‐transcriptional regulation of NeuroD.
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Affiliation(s)
- Scott M Taylor
- Department of Biology, University of West Florida, 11000 University Parkway, Pensacola, Florida, 32514
| | - Emily Giuffre
- Department of Biology, University of West Florida, 11000 University Parkway, Pensacola, Florida, 32514
| | - Patience Moseley
- Department of Biology, University of West Florida, 11000 University Parkway, Pensacola, Florida, 32514
| | - Peter F Hitchcock
- Ophthalmology and Visual Sciences, University of Michigan, W. K. Kellogg Eye Center, 1000 Wall Street, Ann Arbor, Michigan, 48105
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14
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Coomer CE, Morris AC. Capn5 Expression in the Healthy and Regenerating Zebrafish Retina. Invest Ophthalmol Vis Sci 2018; 59:3643-3654. [PMID: 30029251 PMCID: PMC6054427 DOI: 10.1167/iovs.18-24278] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/01/2018] [Indexed: 12/21/2022] Open
Abstract
Purpose Autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) is a devastating inherited autoimmune disease of the eye that displays features commonly seen in other eye diseases, such as retinitis pigmentosa and diabetic retinopathy. ADNIV is caused by a gain-of-function mutation in Calpain-5 (CAPN5), a calcium-dependent cysteine protease. Very little is known about the normal function of CAPN5 in the adult retina, and there are conflicting results regarding its role during mammalian embryonic development. The zebrafish (Danio rerio) is an excellent animal model for studying vertebrate development and tissue regeneration, and represents a novel model to explore the function of Capn5 in the eye. Methods We characterized the expression of Capn5 in the developing zebrafish central nervous system (CNS) and retina, in the adult zebrafish retina, and in response to photoreceptor degeneration and regeneration using whole-mount in situ hybridization, FISH, and immunohistochemistry. Results In zebrafish, capn5 is strongly expressed in the developing embryonic brain, early optic vesicles, and in newly differentiated retinal photoreceptors. We found that expression of capn5 colocalized with cone-specific markers in the adult zebrafish retina. We observed an increase in expression of Capn5 in a zebrafish model of chronic rod photoreceptor degeneration and regeneration. Acute light damage to the zebrafish retina was accompanied by an increase in expression of Capn5 in the surviving cones and in a subset of Müller glia. Conclusions These studies suggest that Capn5 may play a role in CNS development, photoreceptor maintenance, and photoreceptor regeneration.
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Affiliation(s)
- Cagney E. Coomer
- Department of Biology, University of Kentucky, Lexington, Kentucky, United States
| | - Ann C. Morris
- Department of Biology, University of Kentucky, Lexington, Kentucky, United States
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15
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Chuang JH, Yarmishyn AA, Hwang DK, Hsu CC, Wang ML, Yang YP, Chien KH, Chiou SH, Peng CH, Chen SJ. Expression profiling of cell-intrinsic regulators in the process of differentiation of human iPSCs into retinal lineages. Stem Cell Res Ther 2018; 9:140. [PMID: 29751772 PMCID: PMC5948821 DOI: 10.1186/s13287-018-0848-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 03/06/2018] [Accepted: 03/16/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Differentiation of human induced pluripotent stem cells (hiPSCs) into retinal lineages offers great potential for medical application. Therefore, it is of crucial importance to know the key intrinsic regulators of differentiation and the specific biomarker signatures of cell lineages. METHODS In this study, we used microarrays to analyze transcriptomes of terminally differentiated retinal ganglion cell (RGC) and retinal pigment epithelium (RPE) lineages, as well as intermediate retinal progenitor cells of optic vesicles (OVs) derived from hiPSCs. In our analysis, we specifically focused on the classes of transcripts that encode intrinsic regulators of gene expression: the transcription factors (TFs) and epigenetic chromatin state regulators. We applied two criteria for the selection of potentially important regulators and markers: firstly, the magnitude of fold-change of upregulation; secondly, the contrasted pattern of differential expression between OV, RGC and RPE lineages. RESULTS We found that among the most highly overexpressed TF-encoding genes in the OV/RGC lineage were three members of the Collier/Olfactory-1/Early B-cell family: EBF1, EBF2 and EBF3. Knockdown of EBF1 led to significant impairment of differentiation of hiPSCs into RGCs. EBF1 was shown to act upstream of ISL1 and BRN3A, the well-characterized regulators of RGC lineage specification. TF-encoding genes DLX1, DLX2 and INSM1 were the most highly overexpressed genes in the OVs, indicating their important role in the early stages of retinal differentiation. Along with MITF, the two paralogs, BHLHE41 and BHLHE40, were the most robust TF markers of RPE cells. The markedly contrasted expression of ACTL6B, encoding the component of chromatin remodeling complex SWI/SNF, discriminated hiPSC-derived OV/RGC and RPE lineages. CONCLUSIONS We identified novel, potentially important intrinsic regulators of RGC and RPE cell lineage specification in the process of differentiation from hiPSCs. We demonstrated the crucial role played by EBF1 in differentiation of RGCs. We identified intrinsic regulator biomarker signatures of these two retinal cell types that can be applied with high confidence to confirm the cell lineage identities.
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Affiliation(s)
- Jen-Hua Chuang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
| | - Aliaksandr A Yarmishyn
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
| | - De-Kuang Hwang
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chih-Chien Hsu
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Mong-Lien Wang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Ping Yang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
| | - Ke-Hung Chien
- Department of Ophthalmology, Tri-Service General Hospital & National Defense Medical Center, Taipei, Taiwan
| | - Shih-Hwa Chiou
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chi-Hsien Peng
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan. .,Department of Ophthalmology, Shin Kong Wu Ho-Su Memorial Hospital and Fu Jen Catholic University, Taipei, Taiwan.
| | - Shih-Jen Chen
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan. .,Department of Ophthalmology, Tri-Service General Hospital & National Defense Medical Center, Taipei, Taiwan. .,School of Medicine, National Yang-Ming University, Taipei, Taiwan.
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16
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Gong J, Wang X, Zhu C, Dong X, Zhang Q, Wang X, Duan X, Qian F, Shi Y, Gao Y, Zhao Q, Chai R, Liu D. Insm1a Regulates Motor Neuron Development in Zebrafish. Front Mol Neurosci 2017; 10:274. [PMID: 28894416 PMCID: PMC5581358 DOI: 10.3389/fnmol.2017.00274] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 08/14/2017] [Indexed: 11/30/2022] Open
Abstract
Insulinoma-associated1a (insm1a) is a zinc-finger transcription factor playing a series of functions in cell formation and differentiation of vertebrate central and peripheral nervous systems and neuroendocrine system. However, its roles on the development of motor neuron have still remained uncovered. Here, we provided evidences that insm1a was a vital regulator of motor neuron development, and provided a mechanistic understanding of how it contributes to this process. Firstly, we showed the localization of insm1a in spinal cord, and primary motor neurons (PMNs) of zebrafish embryos by in situ hybridization, and imaging analysis of transgenic reporter line Tg(insm1a: mCherry)ntu805. Then we demonstrated that the deficiency of insm1a in zebrafish larvae lead to the defects of PMNs development, including the reduction of caudal primary motor neurons (CaP), and middle primary motor neurons (MiP), the excessive branching of motor axons, and the disorganized distance between adjacent CaPs. Additionally, knockout of insm1 impaired motor neuron differentiation in the spinal cord. Locomotion analysis showed that swimming activity was significantly reduced in the insm1a-null zebrafish. Furthermore, we showed that the insm1a loss of function significantly decreased the transcript levels of both olig2 and nkx6.1. Microinjection of olig2 and nkx6.1 mRNA rescued the motor neuron defects in insm1a deficient embryos. Taken together, these data indicated that insm1a regulated the motor neuron development, at least in part, through modulation of the expressions of olig2 and nkx6.1.
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Affiliation(s)
- Jie Gong
- School of Life Science, Nantong UniversityNantong, China
| | - Xin Wang
- Co-innovation Center of Neuroregeneration, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong UniversityNantong, China
| | - Chenwen Zhu
- Co-innovation Center of Neuroregeneration, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong UniversityNantong, China
| | - Xiaohua Dong
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing UniversityNanjing, China
| | - Qinxin Zhang
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing UniversityNanjing, China
| | - Xiaoning Wang
- Co-innovation Center of Neuroregeneration, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong UniversityNantong, China
| | - Xuchu Duan
- School of Life Science, Nantong UniversityNantong, China
| | - Fuping Qian
- Co-innovation Center of Neuroregeneration, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong UniversityNantong, China.,Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Yunwei Shi
- Co-innovation Center of Neuroregeneration, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong UniversityNantong, China
| | - Yu Gao
- Co-innovation Center of Neuroregeneration, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong UniversityNantong, China
| | - Qingshun Zhao
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing UniversityNanjing, China
| | - Renjie Chai
- Co-innovation Center of Neuroregeneration, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong UniversityNantong, China.,Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Dong Liu
- Co-innovation Center of Neuroregeneration, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong UniversityNantong, China
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17
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He Y, Lu X, Qian F, Liu D, Chai R, Li H. Insm1a Is Required for Zebrafish Posterior Lateral Line Development. Front Mol Neurosci 2017; 10:241. [PMID: 28824372 PMCID: PMC5539400 DOI: 10.3389/fnmol.2017.00241] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/17/2017] [Indexed: 12/23/2022] Open
Abstract
Insulinoma-associated 1 (Insm1), a zinc-finger transcription factor, is widely expressed in the developing nervous system and plays important roles in cell cycle progression and cell fate specification. However, the functions of Insm1 in the embryonic development of the sensory system and its underlying molecular mechanisms remain largely unexplored. Here, through whole-mount in situ hybridization, we found that the zebrafish insm1a gene was expressed in the posterior lateral line (pLL) system, including both the migrating pLL primordium and the deposited neuromast cells. In order to decipher the specific roles of insm1a in zebrafish pLL development, we inhibited insm1a expression by using a morpholino knockdown strategy. The insm1a morphants exhibited primordium migration defects that resulted in reduced numbers of neuromasts. The inactivation of insm1a reduced the numbers of hair cells in neuromasts, and this defect could be a secondary consequence of disrupting rosette formation in the pLL primordium. Additionally, we showed that insm1a knockdown decreased the proliferation of pLL primordium cells, which likely contributed to these pLL defects. Furthermore, we showed that loss of insm1a resulted in elevated Wnt/β-catenin signaling and downregulation of Fgf target genes in the primordium. Insm1a knockdown also perturbed the expression patterns of chemokine signaling genes. Taken together, this study reveals a pivotal role for Insm1a in regulating pLL development during zebrafish embryogenesis.
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Affiliation(s)
- Yingzi He
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China.,Key Laboratory of Hearing Medicine of NHFPCShanghai, China
| | - Xiaoling Lu
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China
| | - Fuping Qian
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China
| | - Dong Liu
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong UniversityNantong, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing, China.,Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong UniversityNantong, China.,Research Institute of OtolaryngologyNanjing, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China.,Key Laboratory of Hearing Medicine of NHFPCShanghai, China.,Institutes of Biomedical Sciences, Fudan UniversityShanghai, China.,Shanghai Engineering Research Centre of Cochlear ImplantShanghai, China.,The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan UniversityShanghai, China
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18
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REST corepressors RCOR1 and RCOR2 and the repressor INSM1 regulate the proliferation-differentiation balance in the developing brain. Proc Natl Acad Sci U S A 2017; 114:E406-E415. [PMID: 28049845 DOI: 10.1073/pnas.1620230114] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The transcriptional events that lead to the cessation of neural proliferation, and therefore enable the production of proper numbers of differentiated neurons and glia, are still largely uncharacterized. Here, we report that the transcription factor Insulinoma-associated 1 (INSM1) forms complexes with RE1 Silencing Transcription factor (REST) corepressors RCOR1 and RCOR2 in progenitors in embryonic mouse brain. Mice lacking both RCOR1 and RCOR2 in developing brain die perinatally and generate an abnormally high number of neural progenitors at the expense of differentiated neurons and oligodendrocyte precursor cells. In addition, Rcor1/2 deletion detrimentally affects complex morphological processes such as closure of the interganglionic sulcus. We find that INSM1, a transcription factor that induces cell-cycle arrest, is coexpressed with RCOR1/2 in a subset of neural progenitors and forms complexes with RCOR1/2 in embryonic brain. Further, the Insm1-/- mouse phenocopies predominant brain phenotypes of the Rcor1/2 knockout. A large number of genes are concordantly misregulated in both knockout genotypes, and a majority of the down-regulated genes are targets of REST. Rest transcripts are up-regulated in both knockouts, and reducing transcripts to control levels in the Rcor1/2 knockout partially rescues the defect in interganglionic sulcus closure. Our findings indicate that an INSM1/RCOR1/2 complex controls the balance of proliferation and differentiation during brain development.
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19
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Bosse JL, El-Hodiri HM. Expression of the insulinoma-associated 1 (insm1) gene in Xenopus laevis tadpole retina and brain. Gene Expr Patterns 2016; 22:26-29. [PMID: 27670931 DOI: 10.1016/j.gep.2016.09.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/21/2016] [Accepted: 09/22/2016] [Indexed: 11/29/2022]
Abstract
The insulinoma-associated 1 (insm1) gene is involved in the differentiation of several neuronal and endoderm derived cell types. insm1 is expressed in the retina and brain of several vertebrates including Xenopus laevis. We report the detailed expression pattern of insm1 in the X. laevis tadpole retina and brain. X. laevis insm1 is expressed in most of the ciliary marginal zone of the mature retina and the optic tectum, dorsal pallium, hypothalamus and preoptic areas of the developing tadpole brain. Overall, insm1 is expressed in regions of the tadpole brain and retina harboring populations of progenitor cells.
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Affiliation(s)
- Jennifer L Bosse
- Graduate Program in Molecular, Cellular, and Developmental Biology, College of Biological Sciences, Ohio State University, Columbus, OH, USA
| | - Heithem M El-Hodiri
- Graduate Program in Molecular, Cellular, and Developmental Biology, College of Biological Sciences, Ohio State University, Columbus, OH, USA; Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, College of Medicine, Ohio State University, Columbus, OH, USA.
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20
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Froldi F, Cheng LY. Understanding how differentiation is maintained: lessons from the Drosophila brain. Cell Mol Life Sci 2016; 73:1641-4. [PMID: 26817462 PMCID: PMC11108259 DOI: 10.1007/s00018-016-2144-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 01/14/2016] [Accepted: 01/18/2016] [Indexed: 12/19/2022]
Abstract
The ability to maintain cells in a differentiated state and to prevent them from reprogramming into a multipotent state has recently emerged as a central theme in neural development as well as in oncogenesis. In the developing central nervous system (CNS) of the fruit fly Drosophila, several transcription factors were recently identified to be required in postmitotic cells to maintain differentiation, and in their absence, mature neurons undergo dedifferentiation, giving rise to proliferative neural stem cells and ultimately to tumor growth. In this review, we will highlight the current understanding of dedifferentiation and cell plasticity in the Drosophila CNS.
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Affiliation(s)
- Francesca Froldi
- Peter MacCallum Cancer Centre, East Melbourne, VIC, 3002, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Louise Y Cheng
- Peter MacCallum Cancer Centre, East Melbourne, VIC, 3002, Australia.
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC, 3010, Australia.
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21
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Wilson SG, Wen W, Pillai-Kastoori L, Morris AC. Tracking the fate of her4 expressing cells in the regenerating retina using her4:Kaede zebrafish. Exp Eye Res 2015; 145:75-87. [PMID: 26616101 DOI: 10.1016/j.exer.2015.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/22/2015] [Accepted: 11/03/2015] [Indexed: 11/26/2022]
Abstract
The Basic-Helix-Loop-Helix-Orange (bHLH-O) transcription factor Hairy-related 4 (her4) is a downstream effector of Notch-Delta signaling that represses expression of typically pro-neural genes in proliferative domains of the central nervous system. Notch-Delta signaling in the retina has been shown to increase in response to injury and influences neuroprotective properties of Müller glia. In contrast to mammals, teleost fish are able to regenerate retinal neurons in response to injury. In zebrafish, her4 is upregulated in the regenerating neural retina in response to both acute and chronic photoreceptor damage, but the contribution of her4 expressing cells to neurogenesis following acute or chronic retinal damage has remained unexplored. Here we investigate the role of her4 in the regenerating retina in a background of chronic, rod-specific degeneration as well as following acute light damage. We demonstrate that her4 is expressed in the persistently neurogenic ciliary marginal zone (CMZ), as well as in small subsets of slowly proliferating Müller glia in the inner nuclear layer (INL) of the central retina. We generated a transgenic line of zebrafish that expresses the photoconvertible Kaede reporter driven by a her4 promoter and validated that expression of the transgene faithfully recapitulates endogenous her4 expression. Lineage tracing analysis revealed that her4-expressing cells in the INL contribute to the rod lineage, and her4 expressing cells in the CMZ are capable of generating any retinal cell type except rod photoreceptors. Our results indicate that her4 is involved in a replenishing pathway that maintains populations of stem cells in the central retina, and that the magnitude of the her4-associated proliferative response mirrors the extent of retinal damage.
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Affiliation(s)
- Stephen G Wilson
- Department of Biology, University of Kentucky, Lexington, 40506-0225, KY, USA
| | - Wen Wen
- Department of Biology, University of Kentucky, Lexington, 40506-0225, KY, USA
| | | | - Ann C Morris
- Department of Biology, University of Kentucky, Lexington, 40506-0225, KY, USA.
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22
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Taylor SM, Alvarez-Delfin K, Saade CJ, Thomas JL, Thummel R, Fadool JM, Hitchcock PF. The bHLH Transcription Factor NeuroD Governs Photoreceptor Genesis and Regeneration Through Delta-Notch Signaling. Invest Ophthalmol Vis Sci 2015; 56:7496-515. [PMID: 26580854 PMCID: PMC4654396 DOI: 10.1167/iovs.15-17616] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 10/06/2015] [Indexed: 01/08/2023] Open
Abstract
PURPOSE Photoreceptor genesis in the retina requires precise regulation of progenitor cell competence, cell cycle exit, and differentiation, although information around the mechanisms that govern these events currently is lacking. In zebrafish, the basic helix-loop-helix (bHLH) transcription factor NeuroD governs photoreceptor genesis, but the signaling pathways through which NeuroD functions are unknown. The purpose of this study was to identify these pathways, and during photoreceptor genesis, Notch signaling was investigated as the putative mediator of NeuroD function. METHODS In embryos, genetic mosaic analysis was used to determine if NeuroD functions is cell- or non-cell-autonomous. Morpholino-induced NeuroD knockdown, CRISPR/Cas9 mutation, and pharmacologic and transgenic approaches were used, followed by in situ hybridization, immunocytochemistry, and quantitative RT-PCR (qRT-PCR), to identify mechanisms through which NeuroD functions. In adults, following photoreceptor ablation and NeuroD knockdown, similar methods as above were used to identify NeuroD function during photoreceptor regeneration. RESULTS In embryos, NeuroD function is non-cell-autonomous, NeuroD knockdown increases Notch pathway gene expression, Notch inhibition rescues the NeuroD knockdown-induced deficiency in cell cycle exit but not photoreceptor maturation, and Notch activation and CRISPR/Cas9 mutation of neurod recapitulate NeuroD knockdown. In adults, NeuroD knockdown prevents cell cycle exit and photoreceptor regeneration and increases Notch pathway gene expression, and Notch inhibition rescues this phenotype. CONCLUSIONS These data demonstrate that during embryonic development, NeuroD governs photoreceptor genesis via non-cell-autonomous mechanisms and that, during photoreceptor development and regeneration, Notch signaling is a mechanistic link between NeuroD and cell cycle exit. In contrast, during embryonic development, NeuroD governs photoreceptor maturation via mechanisms that are independent of Notch signaling.
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Affiliation(s)
- Scott M. Taylor
- Department of Ophthalmology and Visual Sciences University of Michigan, W. K. Kellogg Eye Center, Ann Arbor, Michigan, United States
| | - Karen Alvarez-Delfin
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States
| | - Carole J. Saade
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States
| | - Jennifer L. Thomas
- Departments of Anatomy/Cell Biology and Ophthalmology, Wayne State University, Detroit, Michigan, United States
| | - Ryan Thummel
- Departments of Anatomy/Cell Biology and Ophthalmology, Wayne State University, Detroit, Michigan, United States
| | - James M. Fadool
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States
| | - Peter F. Hitchcock
- Department of Ophthalmology and Visual Sciences University of Michigan, W. K. Kellogg Eye Center, Ann Arbor, Michigan, United States
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23
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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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24
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Froldi F, Szuperak M, Weng CF, Shi W, Papenfuss AT, Cheng LY. The transcription factor Nerfin-1 prevents reversion of neurons into neural stem cells. Genes Dev 2015; 29:129-43. [PMID: 25593306 PMCID: PMC4298133 DOI: 10.1101/gad.250282.114] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Froldi et al. show that the Drosophila zinc finger transcription factor Nervous fingers 1 (Nerfin-1) locks neurons into differentiation, preventing their reversion into neuroblasts. The loss of Nerfin-1 causes reversion to multipotency and results in tumors in several neural lineages. RNA-seq and ChIP analysis show that Nerfin-1 administers its function by repression of self-renewing genes and activation of differentiation-specific genes. Cellular dedifferentiation is the regression of a cell from a specialized state to a more multipotent state and is implicated in cancer. However, the transcriptional network that prevents differentiated cells from reacquiring stem cell fate is so far unclear. Neuroblasts (NBs), the Drosophila neural stem cells, are a model for the regulation of stem cell self-renewal and differentiation. Here we show that the Drosophila zinc finger transcription factor Nervous fingers 1 (Nerfin-1) locks neurons into differentiation, preventing their reversion into NBs. Following Prospero-dependent neuronal specification in the ganglion mother cell (GMC), a Nerfin-1-specific transcriptional program maintains differentiation in the post-mitotic neurons. The loss of Nerfin-1 causes reversion to multipotency and results in tumors in several neural lineages. Both the onset and rate of neuronal dedifferentiation in nerfin-1 mutant lineages are dependent on Myc- and target of rapamycin (Tor)-mediated cellular growth. In addition, Nerfin-1 is required for NB differentiation at the end of neurogenesis. RNA sequencing (RNA-seq) and chromatin immunoprecipitation (ChIP) analysis show that Nerfin-1 administers its function by repression of self-renewing-specific and activation of differentiation-specific genes. Our findings support the model of bidirectional interconvertibility between neural stem cells and their post-mitotic progeny and highlight the importance of the Nerfin-1-regulated transcriptional program in neuronal maintenance.
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Affiliation(s)
- Francesca Froldi
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Milan Szuperak
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Chen-Fang Weng
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Wei Shi
- Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Computing and Information Systems, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Anthony T Papenfuss
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia; Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Louise Y Cheng
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia;
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25
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Wen W, Pillai-Kastoori L, Wilson SG, Morris AC. Sox4 regulates choroid fissure closure by limiting Hedgehog signaling during ocular morphogenesis. Dev Biol 2014; 399:139-153. [PMID: 25557621 DOI: 10.1016/j.ydbio.2014.12.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 12/15/2014] [Accepted: 12/22/2014] [Indexed: 01/20/2023]
Abstract
SoxC transcription factors play critical roles in many developmental processes, including neurogenesis, cardiac formation, and skeletal differentiation. In vitro and in vivo loss-of-function studies have suggested that SoxC genes are required for oculogenesis; however the mechanism was poorly understood. Here, we have explored the function of the SoxC factor Sox4 during zebrafish eye development. We show that sox4a and sox4b are expressed in the forebrain and periocular mesenchyme adjacent to the optic stalk during early eye development. Knockdown of sox4 in zebrafish resulted in coloboma, a structural malformation of the eye that is a significant cause of pediatric visual impairment in humans, in which the choroid fissure fails to close. Sox4 morphants displayed altered proximo-distal patterning of the optic vesicle, including expanded pax2 expression in the optic stalk, as well as ectopic cell proliferation in the retina. We show that the abnormal ocular morphogenesis observed in Sox4-deficient zebrafish is caused by elevated Hedgehog (Hh) signaling, and this is due to increased expression of the Hh pathway ligand Indian Hedgehog b (ihhb). Consistent with these results, coloboma in sox4 morphants could be rescued by pharmacological treatment with the Hh inhibitor cyclopamine, or by co-knockdown of ihhb. Conversely, overexpression of sox4 reduced Hh signaling and ihhb expression, resulting in cyclopia. Finally, we demonstrate that sox4 and sox11 have overlapping, but not completely redundant, functions in regulating ocular morphogenesis. Taken together, our data demonstrate that Sox4 is required to limit the extent of Hh signaling during eye development, and suggest that mutations in SoxC factors could contribute to the development of coloboma.
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Affiliation(s)
- Wen Wen
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA
| | | | - Stephen G Wilson
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA
| | - Ann C Morris
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA.
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26
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Pillai-Kastoori L, Wen W, Wilson SG, Strachan E, Lo-Castro A, Fichera M, Musumeci SA, Lehmann OJ, Morris AC. Sox11 is required to maintain proper levels of Hedgehog signaling during vertebrate ocular morphogenesis. PLoS Genet 2014; 10:e1004491. [PMID: 25010521 PMCID: PMC4091786 DOI: 10.1371/journal.pgen.1004491] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 05/21/2014] [Indexed: 11/29/2022] Open
Abstract
Ocular coloboma is a sight-threatening malformation caused by failure of the choroid fissure to close during morphogenesis of the eye, and is frequently associated with additional anomalies, including microphthalmia and cataracts. Although Hedgehog signaling is known to play a critical role in choroid fissure closure, genetic regulation of this pathway remains poorly understood. Here, we show that the transcription factor Sox11 is required to maintain specific levels of Hedgehog signaling during ocular development. Sox11-deficient zebrafish embryos displayed delayed and abnormal lens formation, coloboma, and a specific reduction in rod photoreceptors, all of which could be rescued by treatment with the Hedgehog pathway inhibitor cyclopamine. We further demonstrate that the elevated Hedgehog signaling in Sox11-deficient zebrafish was caused by a large increase in shha transcription; indeed, suppressing Shha expression rescued the ocular phenotypes of sox11 morphants. Conversely, over-expression of sox11 induced cyclopia, a phenotype consistent with reduced levels of Sonic hedgehog. We screened DNA samples from 79 patients with microphthalmia, anophthalmia, or coloboma (MAC) and identified two novel heterozygous SOX11 variants in individuals with coloboma. In contrast to wild type human SOX11 mRNA, mRNA containing either variant failed to rescue the lens and coloboma phenotypes of Sox11-deficient zebrafish, and both exhibited significantly reduced transactivation ability in a luciferase reporter assay. Moreover, decreased gene dosage from a segmental deletion encompassing the SOX11 locus resulted in microphthalmia and related ocular phenotypes. Therefore, our study reveals a novel role for Sox11 in controlling Hedgehog signaling, and suggests that SOX11 variants contribute to pediatric eye disorders.
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Affiliation(s)
- Lakshmi Pillai-Kastoori
- Department of Biology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Wen Wen
- Department of Biology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Stephen G. Wilson
- Department of Biology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Erin Strachan
- Departments of Ophthalmology and Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Adriana Lo-Castro
- Department of Neuroscience, Pediatric Neurology Unit, “Tor Vergata” University of Rome, Rome, Italy
| | - Marco Fichera
- Laboratory of Medical Genetics, IRCCS Associazione Oasi Maria Santissima, Troina, Italy, and Medical Genetics, University of Catania, Catania, Italy
| | | | - Ordan J. Lehmann
- Departments of Ophthalmology and Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Ann C. Morris
- Department of Biology, University of Kentucky, Lexington, Kentucky, United States of America
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27
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Lenkowski JR, Raymond PA. Müller glia: Stem cells for generation and regeneration of retinal neurons in teleost fish. Prog Retin Eye Res 2014; 40:94-123. [PMID: 24412518 DOI: 10.1016/j.preteyeres.2013.12.007] [Citation(s) in RCA: 223] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 12/28/2013] [Accepted: 12/30/2013] [Indexed: 12/31/2022]
Abstract
Adult zebrafish generate new neurons in the brain and retina throughout life. Growth-related neurogenesis allows a vigorous regenerative response to damage, and fish can regenerate retinal neurons, including photoreceptors, and restore functional vision following photic, chemical, or mechanical destruction of the retina. Müller glial cells in fish function as radial-glial-like neural stem cells. During adult growth, Müller glial nuclei undergo sporadic, asymmetric, self-renewing mitotic divisions in the inner nuclear layer to generate a rod progenitor that migrates along the radial fiber of the Müller glia into the outer nuclear layer, proliferates, and differentiates exclusively into rod photoreceptors. When retinal neurons are destroyed, Müller glia in the immediate vicinity of the damage partially and transiently dedifferentiate, re-express retinal progenitor and stem cell markers, re-enter the cell cycle, undergo interkinetic nuclear migration (characteristic of neuroepithelial cells), and divide once in an asymmetric, self-renewing division to generate a retinal progenitor. This daughter cell proliferates rapidly to form a compact neurogenic cluster surrounding the Müller glia; these multipotent retinal progenitors then migrate along the radial fiber to the appropriate lamina to replace missing retinal neurons. Some aspects of the injury-response in fish Müller glia resemble gliosis as observed in mammals, and mammalian Müller glia exhibit some neurogenic properties, indicative of a latent ability to regenerate retinal neurons. Understanding the specific properties of fish Müller glia that facilitate their robust capacity to generate retinal neurons will inform and inspire new clinical approaches for treating blindness and visual loss with regenerative medicine.
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Affiliation(s)
- Jenny R Lenkowski
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, USA.
| | - Pamela A Raymond
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, USA.
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