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Dénes V, Kovacs K, Lukáts Á, Mester A, Berta G, Szabó A, Gabriel R. Secreted key regulators (Fgf1, Bmp4, Gdf3) are expressed by PAC1-immunopositive retinal ganglion cells in the postnatal rat retina. Eur J Histochem 2022; 66. [PMID: 35477223 PMCID: PMC9087371 DOI: 10.4081/ejh.2022.3373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/02/2022] [Indexed: 11/22/2022] Open
Abstract
Identified as a member of the secretin/glucagon/VIP superfamily, pituitary adenylate cyclase-activating polypeptide (PACAP1-38) has been recognized as a hormone, neurohormone, transmitter, trophic factor, and known to be involved in diverse and multiple developmental processes. PACAP1-38 was reported to regulate the production of important morphogens (Fgf1, Bmp4, Gdf3) through PAC1-receptor in the newborn rat retina. To follow up, we aimed to reveal the identity of retinal cells responsible for the production and secretion of Fgf1, Bmp4, and Gdf3 in response to PACAP1-38 treatment. Newborn (P1) rats were treated with 100 pmol PACAP1-38 intravitreally. After 24 h, retinas were dissected and processed for immunohistochemistry performed either on flat-mounted retinas or cryosections. Brn3a and PAC1-R double labeling revealed that 90% of retinal ganglion cells (RGCs) expressed PAC1-receptor. We showed that RGCs were Fgf1, Bmp4, and Gdf3- immunopositive and PAC1-R was co-expressed with each protein. To elucidate if RGCs release these secreted regulators, the key components for vesicle release were examined. No labeling was detected for synaptophysin, Exo70, or NESP55 in RGCs but an intense Rab3a-immunoreactivity was detected in their cell bodies. We found that the vast majority of RGCs are responsive to PACAP, which in turn could have a significant impact on their development or/and physiology. Although Fgf1, Bmp4, and Gdf3 were abundantly expressed in PAC1-positive RGCs, the cells lack synaptophysin and Exo70 in the newborn retina thus unable to release these proteins. These proteins could regulate postnatal RGC development acting through intracrine pathways.
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Affiliation(s)
- Viktória Dénes
- Department of Experimental Zoology and Neurobiology, University of Pécs.
| | - Kármen Kovacs
- Department of Experimental Zoology and Neurobiology, University of Pécs.
| | - Ákos Lukáts
- Department of Experimental Zoology and Neurobiology, University of Pécs; Department of Translational Medicine, Semmelweis University, Budapest.
| | - Adrienn Mester
- Department of Experimental Zoology and Neurobiology, University of Pécs.
| | - Gergely Berta
- Institute of Medical Biology, School of Medicine, University of Pécs.
| | - Arnold Szabó
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest.
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pécs.
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2
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Karouta C, Kucharski R, Hardy K, Thomson K, Maleszka R, Morgan I, Ashby R. Transcriptome-based insights into gene networks controlling myopia prevention. FASEB J 2021; 35:e21846. [PMID: 34405458 DOI: 10.1096/fj.202100350rr] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 11/11/2022]
Abstract
Myopia (short-sightedness), usually caused by excessive elongation of the eye during development, has reached epidemic proportions worldwide. In animal systems including the chicken model, several treatments have been shown to inhibit ocular elongation and experimental myopia. Although diverse in their apparent mechanism of action, each one leads to a reduction in the rate of ocular growth. We hypothesize that a defined set of retinal molecular changes may underlie growth inhibition, irrespective of the treatment agent used. Accordingly, across five well-established but diverse methods of inhibiting myopia, significant overlap is seen in the retinal transcriptome profile (transcript levels and alternative splicing events) in chicks when analyzed by RNA-seq. Within the two major pathway networks enriched during growth inhibition, that of cell signaling and circadian entrainment, transcription factors form the largest functional grouping. Importantly, a large percentage of those genes forming the defined retinal response are downstream targets of the transcription factor EGR1 which itself shows a universal response to all five growth-inhibitory treatments. This supports EGR1's previously implicated role in ocular growth regulation. Finally, by contrasting our data with human linkage and GWAS studies on refractive error, we confirm the applicability of our study to the human condition. Together, these findings suggest that a universal set of transcriptome changes, which sit within a well-defined retinal network that cannot be bypassed, is fundamental to growth regulation, thus paving a way for designing novel targets for myopia therapies.
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Affiliation(s)
- Cindy Karouta
- Centre for Research in Therapeutic Solutions, Biomedical Sciences, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Robert Kucharski
- Centre for Research in Therapeutic Solutions, Biomedical Sciences, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia.,Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Kristine Hardy
- Centre for Research in Therapeutic Solutions, Biomedical Sciences, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Kate Thomson
- Centre for Research in Therapeutic Solutions, Biomedical Sciences, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Ryszard Maleszka
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Ian Morgan
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Regan Ashby
- Centre for Research in Therapeutic Solutions, Biomedical Sciences, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia.,Research School of Biology, Australian National University, Canberra, ACT, Australia
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Wagstaff EL, Heredero Berzal A, Boon CJF, Quinn PMJ, ten Asbroek ALMA, Bergen AA. The Role of Small Molecules and Their Effect on the Molecular Mechanisms of Early Retinal Organoid Development. Int J Mol Sci 2021; 22:7081. [PMID: 34209272 PMCID: PMC8268497 DOI: 10.3390/ijms22137081] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/23/2021] [Accepted: 06/26/2021] [Indexed: 12/12/2022] Open
Abstract
Early in vivo embryonic retinal development is a well-documented and evolutionary conserved process. The specification towards eye development is temporally controlled by consecutive activation or inhibition of multiple key signaling pathways, such as the Wnt and hedgehog signaling pathways. Recently, with the use of retinal organoids, researchers aim to manipulate these pathways to achieve better human representative models for retinal development and disease. To achieve this, a plethora of different small molecules and signaling factors have been used at various time points and concentrations in retinal organoid differentiations, with varying success. Additions differ from protocol to protocol, but their usefulness or efficiency has not yet been systematically reviewed. Interestingly, many of these small molecules affect the same and/or multiple pathways, leading to reduced reproducibility and high variability between studies. In this review, we make an inventory of the key signaling pathways involved in early retinogenesis and their effect on the development of the early retina in vitro. Further, we provide a comprehensive overview of the small molecules and signaling factors that are added to retinal organoid differentiation protocols, documenting the molecular and functional effects of these additions. Lastly, we comparatively evaluate several of these factors using our established retinal organoid methodology.
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Affiliation(s)
- Ellie L. Wagstaff
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam (UvA), 1105 AZ Amsterdam, The Netherlands;
| | - Andrea Heredero Berzal
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam (UvA), 1105 AZ Amsterdam, The Netherlands; (A.H.B.); (C.J.F.B.)
| | - Camiel J. F. Boon
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam (UvA), 1105 AZ Amsterdam, The Netherlands; (A.H.B.); (C.J.F.B.)
- Department of Ophthalmology, Leiden University Medical Center (LUMC), 2333 ZA Leiden, The Netherlands
| | - Peter M. J. Quinn
- Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology & Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA; Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center—New York-Presbyterian Hospital, New York, NY 10032, USA;
| | | | - Arthur A. Bergen
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam (UvA), 1105 AZ Amsterdam, The Netherlands;
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam (UvA), 1105 AZ Amsterdam, The Netherlands; (A.H.B.); (C.J.F.B.)
- Netherlands Institute for Neuroscience (NIN-KNAW), 1105 BA Amsterdam, The Netherlands
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4
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Moazzeni H, Khani M, Elahi E. Insights into the regulatory molecules involved in glaucoma pathogenesis. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:782-827. [PMID: 32935930 DOI: 10.1002/ajmg.c.31833] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/26/2020] [Accepted: 07/28/2020] [Indexed: 12/19/2022]
Abstract
Glaucoma is an important cause of irreversible blindness, characterized by optic nerve anomalies. Increased intraocular pressure (IOP) and aging are major risk factors. Retinal ganglion cells and trabecular meshwork cells are certainly involved in the etiology of glaucoma. Glaucoma is usually a complex disease, and various genes and functions may contribute to its etiology. Among these may be genes that encode regulatory molecules. In this review, regulatory molecules including 18 transcription factors (TFs), 195 microRNAs (miRNAs), 106 long noncoding RNAs (lncRNAs), and two circular RNAs (circRNAs) that are reasonable candidates for having roles in glaucoma pathogenesis are described. The targets of the regulators are reported. Glaucoma-related features including apoptosis, stress responses, immune functions, ECM properties, IOP, and eye development are affected by the targeted genes. The targeted genes that are frequently targeted by multiple regulators most often affect apoptosis and the related features of cell death and cell survival. BCL2, CDKN1A, and TP53 are among the frequent targets of three types of glaucoma-relevant regulators, TFs, miRNAs, and lncRNAs. TP53 was itself identified as a glaucoma-relevant TF. Several of the glaucoma-relevant TFs are themselves among frequent targets of regulatory molecules, which is consistent with existence of a complex network involved in glaucoma pathogenesis.
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Affiliation(s)
- Hamidreza Moazzeni
- School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Marzieh Khani
- School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Elahe Elahi
- School of Biology, College of Science, University of Tehran, Tehran, Iran
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5
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Moazzeni H, Mirrahimi M, Moghadam A, Banaei-Esfahani A, Yazdani S, Elahi E. Identification of genes involved in glaucoma pathogenesis using combined network analysis and empirical studies. Hum Mol Genet 2019; 28:3637-3663. [PMID: 31518395 DOI: 10.1093/hmg/ddz222] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/30/2019] [Accepted: 09/04/2019] [Indexed: 12/25/2022] Open
Abstract
Glaucoma is a leading cause of blindness. We aimed in this study to identify genes that may make subtle and cumulative contributions to glaucoma pathogenesis. To this end, we identified molecular interactions and pathways that include transcription factors (TFs) FOXC1, PITX2, PAX6 and NFKB1 and various microRNAs including miR-204 known to have relevance to trabecular meshwork (TM) functions and/or glaucoma. TM tissue is involved in glaucoma pathogenesis. In-house microarray transcriptome results and data sources were used to identify target genes of the regulatory molecules. Bioinformatics analyses were done to filter TM and glaucoma relevant genes. These were submitted to network-creating softwares to define interactions, pathways and a network that would include the genes. The network was stringently scrutinized and minimized, then expanded by addition of microarray data and data on TF and microRNA-binding sites. Selected features of the network were confirmed by empirical studies such as dual luciferase assays, real-time PCR and western blot experiments and apoptosis assays. MYOC, WDR36, LTPBP2, RHOA, CYP1B1, OPA1, SPARC, MEIS2, PLEKHG5, RGS5, BBS5, ALDH1A1, NOMO2, CXCL6, FMNL2, ADAMTS5, CLOCK and DKK1 were among the genes included in the final network. Pathways identified included those that affect ECM properties, IOP, ciliary body functions, retinal ganglion cell viability, apoptosis, focal adhesion and oxidative stress response. The identification of many genes potentially involved in glaucoma pathology is consistent with its being a complex disease. The inclusion of several known glaucoma-related genes validates the approach used.
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Affiliation(s)
- Hamidreza Moazzeni
- School of Biology, College of Science, University of Tehran, Tehran, Iran
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mehraban Mirrahimi
- School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Abolfazl Moghadam
- School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Amir Banaei-Esfahani
- Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran
| | - Shahin Yazdani
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elahe Elahi
- School of Biology, College of Science, University of Tehran, Tehran, Iran
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6
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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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7
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Mitra S, Sharma P, Kaur S, Khursheed MA, Gupta S, Chaudhary M, Kurup AJ, Ramachandran R. Dual regulation of lin28a by Myc is necessary during zebrafish retina regeneration. J Cell Biol 2019; 218:489-507. [PMID: 30606747 PMCID: PMC6363449 DOI: 10.1083/jcb.201802113] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 08/31/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023] Open
Abstract
Cellular reprogramming leading to induction of Muller glia-derived progenitor cells (MGPCs) with stem cell characteristics is essential for zebrafish retina regeneration. Although several regeneration-specific genes are characterized, the significance of MGPC-associated Mycb induction remains unknown. Here, we show that early expression of Mycb induces expression of genes like ascl1a, a known activator of lin28a in MGPCs. Notably, mycb is simultaneously activated by Ascl1a and repressed by Insm1a in regenerating retina. Here, we unravel a dual role of Mycb in lin28a expression, both as an activator through Ascl1a in MGPCs and a repressor in combination with Hdac1 in neighboring cells. Myc inhibition reduces the number of MGPCs and abolishes normal regeneration. Myc in collaboration with Hdac1 inhibits her4.1, an effector of Delta-Notch signaling. Further, we also show the repressive role of Delta-Notch signaling on lin28a expression in post-injured retina. Our studies reveal mechanistic understanding of Myc pathway during zebrafish retina regeneration, which could pave way for therapeutic intervention during mammalian retina regeneration.
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Affiliation(s)
- Soumitra Mitra
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Poonam Sharma
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Simran Kaur
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Mohammad Anwar Khursheed
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Shivangi Gupta
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Mansi Chaudhary
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Akshai J Kurup
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
| | - Rajesh Ramachandran
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, India
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8
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Yang JLJ, Bertolesi GE, Hehr CL, Johnston J, McFarlane S. Fibroblast growth factor receptor 1 signaling transcriptionally regulates the axon guidance cue slit1. Cell Mol Life Sci 2018; 75:3649-3661. [PMID: 29705951 PMCID: PMC11105281 DOI: 10.1007/s00018-018-2824-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 04/19/2018] [Accepted: 04/23/2018] [Indexed: 12/31/2022]
Abstract
Axons sense molecular cues in their environment to arrive at their post-synaptic targets. While many of the molecular cues have been identified, the mechanisms that regulate their spatiotemporal expression remain elusive. We examined here the transcriptional regulation of the guidance gene slit1 both in vitro and in vivo by specific fibroblast growth factor receptors (Fgfrs). We identified an Fgf-responsive 2.3 kb slit1 promoter sequence that recapitulates spatiotemporal endogenous expression in the neural tube and eye of Xenopus embryos. We found that signaling through Fgfr1 is the main regulator of slit1 expression both in vitro in A6 kidney epithelial cells, and in the Xenopus forebrain, even when other Fgfr subtypes are present in cells. These data argue that a specific signaling pathway downstream of Fgfr1 controls in a cell-autonomous manner slit1 forebrain expression and are novel in identifying a specific growth factor receptor for in vivo control of the expression of a key embryonic axon guidance cue.
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Affiliation(s)
- Jung-Lynn Jonathan Yang
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB, T2N 4N1, Canada
| | - Gabriel E Bertolesi
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB, T2N 4N1, Canada
| | - Carrie L Hehr
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB, T2N 4N1, Canada
| | - Jillian Johnston
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB, T2N 4N1, Canada
| | - Sarah McFarlane
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB, T2N 4N1, Canada.
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9
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Mitra S, Sharma P, Kaur S, Khursheed MA, Gupta S, Ahuja R, Kurup AJ, Chaudhary M, Ramachandran R. Histone Deacetylase-Mediated Müller Glia Reprogramming through Her4.1-Lin28a Axis Is Essential for Retina Regeneration in Zebrafish. iScience 2018; 7:68-84. [PMID: 30267687 PMCID: PMC6135741 DOI: 10.1016/j.isci.2018.08.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 07/18/2018] [Accepted: 08/10/2018] [Indexed: 12/22/2022] Open
Abstract
Histone deacetylases (Hdacs) play significant roles in cellular homeostasis and tissue differentiation. Hdacs are well characterized in various systems for their physiological and epigenetic relevance. However, their significance during retina regeneration remains unclear. Here we show that inhibition of Hdac1 causes a decline in regenerative ability, and injury-dependent regulation of hdacs is essential for regulating regeneration-associated genes like ascl1a, lin28a, and repressors like her4.1 at the injury site. We show selective seclusion of Hdac1 from the proliferating Müller glia-derived progenitor cells (MGPCs) and its upregulation in the neighboring cells. Hdacs negatively regulate her4.1, which also represses lin28a and essential cytokines to control MGPCs proliferation. Interestingly, Hdacs' inhibition reversibly blocks regeneration through the repression of critical cytokines and other regeneration-specific genes, which is also revealed by whole-retina RNA sequence analysis. Our study shows mechanistic understanding of the Hdac pathway during zebrafish retina regeneration. Hdac1, along with other Hdacs, is a key regulator of retina regeneration in zebrafish Hdacs regulate MGPCs' formation through Her4.1/Lin28a/let-7 miRNA axis Hdacs' inhibition reversibly blocks MGPCs' proliferation and retina regeneration Hdacs/Her4.1 interplay regulates essential cytokines during retina regeneration
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Affiliation(s)
- Soumitra Mitra
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Room 3F10, Academic Block-1, Sector 81, SAS Nagar, Manauli PO, Mohali, Punjab 140306, India
| | - Poonam Sharma
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Room 3F10, Academic Block-1, Sector 81, SAS Nagar, Manauli PO, Mohali, Punjab 140306, India
| | - Simran Kaur
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Room 3F10, Academic Block-1, Sector 81, SAS Nagar, Manauli PO, Mohali, Punjab 140306, India
| | - Mohammad Anwar Khursheed
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Room 3F10, Academic Block-1, Sector 81, SAS Nagar, Manauli PO, Mohali, Punjab 140306, India
| | - Shivangi Gupta
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Room 3F10, Academic Block-1, Sector 81, SAS Nagar, Manauli PO, Mohali, Punjab 140306, India
| | - Riya Ahuja
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Room 3F10, Academic Block-1, Sector 81, SAS Nagar, Manauli PO, Mohali, Punjab 140306, India
| | - Akshai J Kurup
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Room 3F10, Academic Block-1, Sector 81, SAS Nagar, Manauli PO, Mohali, Punjab 140306, India
| | - Mansi Chaudhary
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Room 3F10, Academic Block-1, Sector 81, SAS Nagar, Manauli PO, Mohali, Punjab 140306, India
| | - Rajesh Ramachandran
- Indian Institute of Science Education and Research, Mohali, Knowledge City, Room 3F10, Academic Block-1, Sector 81, SAS Nagar, Manauli PO, Mohali, Punjab 140306, India.
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10
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Simões MG, Bensimon-Brito A, Fonseca M, Farinho A, Valério F, Sousa S, Afonso N, Kumar A, Jacinto A. Denervation impairs regeneration of amputated zebrafish fins. BMC DEVELOPMENTAL BIOLOGY 2014; 14:49. [PMID: 25551555 PMCID: PMC4333893 DOI: 10.1186/s12861-014-0049-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 12/18/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND Zebrafish are able to regenerate many of its tissues and organs after damage. In amphibians this process is regulated by nerve fibres present at the site of injury, which have been proposed to release factors into the amputated limbs/fins, promoting and sustaining the proliferation of blastemal cells. Although some candidate factors have been proposed to mediate the nerve dependency of regeneration, the molecular mechanisms involved in this process remain unclear. RESULTS We have used zebrafish as a model system to address the role of nerve fibres in fin regeneration. We have developed a protocol for pectoral fin denervation followed by amputation and analysed the regenerative process under this experimental conditions. Upon denervation fins were able to close the wound and form a wound epidermis, but could not establish a functional apical epithelial cap, with a posterior failure of blastema formation and outgrowth, and the accumulation of several defects. The expression patterns of genes known to be key players during fin regeneration were altered upon denervation, suggesting that nerves can contribute to the regulation of the Fgf, Wnt and Shh pathways during zebrafish fin regeneration. CONCLUSIONS Our results demonstrate that proper innervation of the zebrafish pectoral fin is essential for a successful regenerative process, and establish this organism as a useful model to understand the molecular and cellular mechanisms of nerve dependence, during vertebrate regeneration.
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Affiliation(s)
- Mariana G Simões
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028, Lisboa, Portugal.
- CEDOC, Chronic Diseases Research Center, NOVA Medical School, NOVA University of Lisbon, Campo dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal.
| | - Anabela Bensimon-Brito
- CEDOC, Chronic Diseases Research Center, NOVA Medical School, NOVA University of Lisbon, Campo dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal.
- Instituto Gulbenkian de Ciência, 2780-156, Oeiras, Portugal.
| | - Mariana Fonseca
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028, Lisboa, Portugal.
| | - Ana Farinho
- CEDOC, Chronic Diseases Research Center, NOVA Medical School, NOVA University of Lisbon, Campo dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal.
| | - Fábio Valério
- CEDOC, Chronic Diseases Research Center, NOVA Medical School, NOVA University of Lisbon, Campo dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal.
| | - Sara Sousa
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028, Lisboa, Portugal.
| | - Nuno Afonso
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028, Lisboa, Portugal.
| | - Anoop Kumar
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, WC1E 6BT, UK.
| | - Antonio Jacinto
- CEDOC, Chronic Diseases Research Center, NOVA Medical School, NOVA University of Lisbon, Campo dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal.
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11
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Atkinson-Leadbeater K, Hehr CL, Mcfarlane S. Fgfr signaling is required as the early eye field forms to promote later patterning and morphogenesis of the eye. Dev Dyn 2014; 243:663-75. [PMID: 24478172 DOI: 10.1002/dvdy.24113] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 01/08/2014] [Accepted: 01/21/2014] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND A major step in eye morphogenesis is the transition from optic vesicle to optic cup, which occurs as a ventral groove forms along the base of the optic vesicle. A ventral gap in the eye, or coloboma, results when this groove fails to close. Extrinsic signals, such as fibroblast growth factors (Fgfs), play a critical role in the development and morphogenesis of the vertebrate eye. Whether these extrinsic signals are required throughout eye development, or within a defined critical period remains an unanswered question. RESULTS Here we show that an early Fgf signal, required as the eye field is first emerging, drives eye morphogenesis. In addition to triggering coloboma, inhibition of this early Fgf signal results in defects in dorsal-ventral patterning of the neural retina, particularly in the nasal retina, and development of the periocular mesenchyme (POM). These processes are unaffected by inhibition of Fgfr signaling at later time points. CONCLUSIONS We propose that Fgfs act within an early critical period as the eye field forms to promote development of the neural retina and POM, which subsequently drive eye morphogenesis.
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12
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Kyosseva SV, Chen L, Seal S, McGinnis JF. Nanoceria inhibit expression of genes associated with inflammation and angiogenesis in the retina of Vldlr null mice. Exp Eye Res 2013; 116:63-74. [PMID: 23978600 DOI: 10.1016/j.exer.2013.08.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/02/2013] [Accepted: 08/06/2013] [Indexed: 12/26/2022]
Abstract
Oxidative stress and inflammation are important pathological mechanisms in many neurodegenerative diseases, including age-related macular degeneration (AMD). The very low-density lipoprotein receptor knockout mouse (Vldlr-/-) has been identified as a model for AMD and in particular for retinal angiomatous proliferation (RAP). In this study we examined the effect of cerium oxide nanoparticles (nanoceria) that have been shown to have catalytic antioxidant activity, on expression of 88 major cytokines in the retinas of Vldlr-/- mice using a PCR array. A single intravitreal injection of nanoceria at P28 caused inhibition of pro-inflammatory cytokines and pro-angiogenic growth factors including Tslp, Lif, Il3, Il7, Vegfa, Fgf1, Fgf2, Fgf7, Egf, Efna3, Lep, and up-regulation of several cytokines and anti-angiogenic genes in the Vldlr-/- retina within one week. We used the Ingenuity Pathway Analysis software to search for biological functions, pathways, and interrelationships between gene networks. Many of the genes whose activities were affected are involved in cell signaling, cellular development, growth and proliferation, and tissue development. Western blot analysis revealed that nanoceria inhibit the activation of ERK 1/2, JNK, p38 MAP kinase, and Akt. These data suggest that nanoceria may represent a novel therapeutic strategy to treat AMD, RAP, and other neurodegenerative diseases.
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Affiliation(s)
- Svetlana V Kyosseva
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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13
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West EL, Pearson RA, Duran Y, Gonzalez-Cordero A, MacLaren RE, Smith AJ, Sowden JC, Ali RR. Manipulation of the recipient retinal environment by ectopic expression of neurotrophic growth factors can improve transplanted photoreceptor integration and survival. Cell Transplant 2012; 21:871-87. [PMID: 22325046 DOI: 10.3727/096368911x623871] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Degeneration of the neural retina is the leading cause of untreatable blindness in the developed world. Stem cell replacement therapy offers a novel strategy for retinal repair. Postmitotic photoreceptor precursors derived from the early postnatal (P) retina are able to migrate and integrate into the adult mouse retina following transplantation into the subretinal space, but it is likely that a large number of these cells would be required to restore vision. The adult recipient retina presents a very different environment to that from which photoreceptor precursor donor cells isolated from the developing postnatal retina are derived. Here we considered the possibility that modulation of the recipient environment by ectopic expression of developmentally regulated growth factors, normally present during photoreceptor development, might enhance the migration and integration of transplanted cells into the adult neural retina. Adeno-associated viral (AAV) vectors were used to introduce three growth factors previously reported to play a role in photoreceptor development, IGF1, FGF2, and CNTF, into the adult retina, prior to transplantation of P4 cells derived from the Nrl.GFP(+ve) neural retina. At 3 weeks posttransplantation the number of integrated, differentiated photoreceptor cells present in AAV-mediated neurotrophic factor-treated eyes was assessed and compared to control treated contralateral eyes. We show, firstly, that it is possible to manipulate the recipient retinal microenvironment via rAAV-mediated gene transfer with respect to these developmentally relevant growth factors. Moreover, when combined with cell transplantation, AAV-mediated expression of IGF1 led to significantly increased levels of cell integration, while overexpression of FGF2 had no significant effect on integrated cell number. Conversely, expression of CNTF led to a significant decrease in cell integration and an exacerbated glial response that led to glial scarring. Together, these findings demonstrate the importance of the extrinsic environment of the recipient retina for photoreceptor cell transplantation and show for the first time that it is possible to manipulate this environment using viral vectors to influence photoreceptor transplantation efficiency.
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Affiliation(s)
- E L West
- Department of Genetics, University College London Institute of Ophthalmology, London, UK
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14
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Fischer AJ, Scott MA, Ritchey ER, Sherwood P. Mitogen-activated protein kinase-signaling regulates the ability of Müller glia to proliferate and protect retinal neurons against excitotoxicity. Glia 2009; 57:1538-52. [PMID: 19306360 PMCID: PMC2775435 DOI: 10.1002/glia.20868] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The purpose of this study was to investigate whether insulin, fibroblast growth factor (FGF), and mitogen-activated protein kinase (MAPK) pathways protect retinal neurons against excitotoxicity and regulate the proliferation of Müller glia. We found that intraocular injections of insulin or FGF2 had variable effects upon the phosphorylation of ERK1/2, p38 MAPK, and CREB, and the expression of immediate early genes, cFos and Egr1. Accumulations of pERK1/2, p38 MAPK, pCREB, cFos and Egr1 in response to insulin or FGF2 were confined to Müller glia, whereas retinal neurons did not seem to respond to growth factors. Unlike FGF2, insulin stimulated microglia-like cells to upregulate the intermediate filament transitin and lysosomal membrane glycoprotein (LMG). With microglia-like cells and Müller glia stimulated by insulin or FGF2 there were profound effects upon numbers of dying neurons in response to excitotoxic damage. Although FGF2 significantly reduced numbers of dying neurons, insulin significantly increased numbers of dying neurons. In addition to neuroprotective affects, FGF2 also "primed" the Müller glia to proliferate following retinal damage, whereas insulin had no effect upon glial proliferation. Further, we found that FGF receptor isoform 1 (FGFR1) and FGFR3 were prominently expressed in the retina, whereas the insulin receptor and FGFR2 are not expressed, or are expressed at very low levels. We conclude that MAPK-signaling through FGF receptors stimulates Müller glia to become more neuroprotective and progenitor-like, whereas insulin acting on Müller and microglia-like cells through unidentified receptors had the opposite effect.
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Affiliation(s)
- Andy J Fischer
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, Ohio 43210-1239, USA.
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15
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Catalani E, Tomassini S, Dal Monte M, Bosco L, Casini G. Localization patterns of fibroblast growth factor 1 and its receptors FGFR1 and FGFR2 in postnatal mouse retina. Cell Tissue Res 2009; 336:423-38. [DOI: 10.1007/s00441-009-0787-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Accepted: 02/23/2009] [Indexed: 11/29/2022]
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16
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Sequential and cooperative action of Fgfs and Shh in the zebrafish retina. Dev Biol 2008; 314:200-14. [DOI: 10.1016/j.ydbio.2007.11.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Revised: 11/19/2007] [Accepted: 11/27/2007] [Indexed: 11/23/2022]
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17
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Cooper JD, Russell C, Mitchison HM. Progress towards understanding disease mechanisms in small vertebrate models of neuronal ceroid lipofuscinosis. BIOCHIMICA ET BIOPHYSICA ACTA 2006; 1762:873-89. [PMID: 17023146 DOI: 10.1016/j.bbadis.2006.08.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 07/28/2006] [Accepted: 08/02/2006] [Indexed: 02/03/2023]
Abstract
Model systems provide an invaluable tool for investigating the molecular mechanisms underlying the NCLs, devastating neurodegenerative disorders that affect the relatively inaccessible tissues of the central nervous system. These models have enabled the assessment of behavioural, pathological, cellular, and molecular abnormalities, and also allow for development and evaluation of novel therapies. This review highlights the relative advantages of the two available small vertebrate species, the mouse and zebrafish, in modelling NCL disease, summarising how these have been useful in NCL research and their potential for the development and testing of prospective disease treatments. A panel of mouse mutants is available representing all the cloned NCL gene disorders (Cathepsin D, CLN1, CLN2, CLN3, CLN5, CLN6, CLN8). These NCL mice all have progressive neurodegenerative phenotypes that closely resemble the pathology of human NCL. The analysis of these models has highlighted several novel aspects underlying NCL pathogenesis including the selective nature of neurodegeneration, evidence for glial responses that precede neuronal loss and identification of the thalamus as an important pathological target early in disease progression. Studies in mice have also highlighted an unexpected heterogeneity underlying NCL phenotypes, and novel potential NCL-like mouse models have been described including mice with mutations in cathepsins, CLC chloride channels, and other lysosome-related genes. These new models are likely to provide significant new information on the spectrum of NCL disease. Information on NCL mice is available in the NCL Mouse Model Database (). There are homologs of most of the NCL genes in zebrafish, and NCL zebrafish models are currently in development. This model system provides additional advantages to those provided by NCL mouse models including high-throughput mutational, pharmacogenetic and therapeutic technique analyses. Mouse and zebrafish models are an important shared resource for NCL research, offering a unique possibility to dissect disease mechanisms and to develop therapeutic approaches.
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Affiliation(s)
- Jonathan D Cooper
- Pediatric Storage Disorders Laboratory, Department of Neuroscience, and Centre for the Cellular Basis of Behaviour, MRC Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, De Crespigny Park, King's College London, London, UK
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18
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Molotkov A, Molotkova N, Duester G. Retinoic acid guides eye morphogenetic movements via paracrine signaling but is unnecessary for retinal dorsoventral patterning. Development 2006; 133:1901-10. [PMID: 16611695 PMCID: PMC2833011 DOI: 10.1242/dev.02328] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Retinoic acid (RA) is required for patterning of the posterior nervous system, but its role in the retina remains unclear. RA is synthesized in discrete regions of the embryonic eye by three retinaldehyde dehydrogenases (RALDHs) displaying distinct expression patterns. Overlapping functions of these enzymes have hampered genetic efforts to elucidate RA function in the eye. Here, we report Raldh1, Raldh2 and Raldh3 single, double and triple null mice exhibiting progressively less or no RA synthesis in the eye. Our genetic studies indicate that RA signaling is not required for the establishment or maintenance of dorsoventral patterning in the retina, as we observe normal expression of Tbx5 and ephrin B2 (Efnb2) dorsally, plus Vax2 and Ephb2 ventrally. Instead, RA is required for the morphogenetic movements needed to shape the developing retina and surrounding mesenchyme. At early stages, Raldh2 expressed in mesenchyme and Raldh3 expressed in the retinal pigmented epithelium generate RA that delivers an essential signal to the neural retina required for morphogenetic movements that lead to ventral invagination of the optic cup. At later stages, Raldh1 expressed in dorsal neural retina and Raldh3 expressed in ventral neural retina (plus weaker expression of each in lens/corneal ectoderm) generates RA that travels to surrounding mesenchyme, where it is needed to limit the anterior invasion of perioptic mesenchyme during the formation of corneal mesenchyme and eyelids. At all stages, RA target tissues are distinct from locations of RA synthesis, indicating that RALDHs function cell-nonautonomously to generate paracrine RA signals that guide morphogenetic movements in neighboring cells.
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19
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Lupo G, Harris WA, Lewis KE. Mechanisms of ventral patterning in the vertebrate nervous system. Nat Rev Neurosci 2006; 7:103-14. [PMID: 16429120 DOI: 10.1038/nrn1843] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Dorsoventral patterning of the neural tube has a crucial role in shaping the functional organization of the CNS. It is well established that hedgehog signalling plays a key role in specifying ventral cell types throughout the neuroectoderm, and major progress has been made in elucidating how hedgehog signalling works in this ventral specification. In addition, other molecular pathways, including nodal, retinoic acid and fibroblast growth factor signalling, have been identified as important molecular cues for ventral patterning of the spinal cord, telencephalon and eye. Here, we discuss recent advances in this field, highlighting the emerging interplay of these signalling pathways in the molecular specification of ventral patterning at different rostrocaudal levels of the CNS.
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Affiliation(s)
- Giuseppe Lupo
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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20
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Picker A, Brand M. Fgf signals from a novel signaling center determine axial patterning of the prospective neural retina. Development 2005; 132:4951-62. [PMID: 16236770 DOI: 10.1242/dev.02071] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Axial eye patterning determines the positional code of retinal ganglion cells (RGCs), which is crucial for their topographic projection to the midbrain. Several asymmetrically expressed determinants of retinal patterning are known, but it is unclear how axial polarity is first established. We find that Fgf signals, including Fgf8, determine retinal patterning along the nasotemporal (NT) axis during early zebrafish embryogenesis: Fgf8 induces nasal and/or suppresses temporal retinal cell fates; and inhibition of all Fgf-receptor signaling leads to complete retinal temporalization and concomitant loss of all nasal fates. Misprojections of RGCs with Fgf-dependent alterations in retinal patterning to the midbrain demonstrate the importance of this early patterning process for late topographic map formation. The crucial period of Fgf-dependent patterning is at the onset of eye morphogenesis. Fgf8 expression, the restricted temporal requirement for Fgf-receptor signaling and target gene expression at this stage suggests that the telencephalic primordium is the source of Fgf8 and acts as novel signaling center for non-autonomous axial patterning of the prospective neural retina.
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Affiliation(s)
- Alexander Picker
- University of Technology, Department of Genetics, c/o Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauer Strasse 108, 01307 Dresden, Germany.
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21
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Barresi MJF, Hutson LD, Chien CB, Karlstrom RO. Hedgehog regulated Slit expression determines commissure and glial cell position in the zebrafish forebrain. Development 2005; 132:3643-56. [PMID: 16033800 DOI: 10.1242/dev.01929] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Three major axon pathways cross the midline of the vertebrate forebrain early in embryonic development: the postoptic commissure (POC), the anterior commissure (AC) and the optic nerve. We show that a small population of Gfap+ astroglia spans the midline of the zebrafish forebrain in the position of, and prior to, commissural and retinal axon crossing. These glial ;bridges' form in regions devoid of the guidance molecules slit2 and slit3, although a subset of these glial cells express slit1a. We show that Hh signaling is required for commissure formation, glial bridge formation, and the restricted expression of the guidance molecules slit1a, slit2, slit3 and sema3d, but that Hh does not appear to play a direct role in commissural and retinal axon guidance. Reducing Slit2 and/or Slit3 function expanded the glial bridges and caused defasciculation of the POC, consistent with a ;channeling' role for these repellent molecules. By contrast, reducing Slit1a function led to reduced midline axon crossing, suggesting a distinct role for Slit1a in midline axon guidance. Blocking Slit2 and Slit3, but not Slit1a, function in the Hh pathway mutant yot (gli2DR) dramatically rescued POC axon crossing and glial bridge formation at the midline, indicating that expanded Slit2 and Slit3 repellent function is largely responsible for the lack of midline crossing in these mutants. This analysis shows that Hh signaling helps to pattern the expression of Slit guidance molecules that then help to regulate glial cell position and axon guidance across the midline of the forebrain.
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22
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Lupo G, Liu Y, Qiu R, Chandraratna RAS, Barsacchi G, He RQ, Harris WA. Dorsoventral patterning of the Xenopus eye: a collaboration of Retinoid, Hedgehog and FGF receptor signaling. Development 2005; 132:1737-48. [PMID: 15753216 DOI: 10.1242/dev.01726] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In the developing spinal cord and telencephalon, ventral patterning involves the interplay of Hedgehog (Hh), Retinoic Acid (RA) and Fibroblast Growth Factor (FGF) signaling. In the eye, ventral specification involves Hh signaling, but the roles of RA and FGF signaling are less clear. By overexpression assays in Xenopus embryos, we found that both RA and FGF receptor (FGFR) signaling ventralize the eye, by expanding optic stalk and ventral retina, and repressing dorsal retina character. Co-overexpression experiments show that RA and FGFR can collaborate with Hh signaling and reinforce its ventralizing activity. In loss-of-function experiments, a strong eye dorsalization was observed after triple inhibition of Hh, RA and FGFR signaling, while weaker effects were obtained by inhibiting only one or two of these pathways. These results suggest that the ventral regionalization of the eye is specified by interactions of Hh, RA and FGFR signaling. We argue that similar mechanisms might control ventral neural patterning throughout the central nervous system.
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Affiliation(s)
- Giuseppe Lupo
- Department of Anatomy, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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23
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Masai I, Yamaguchi M, Tonou-Fujimori N, Komori A, Okamoto H. The hedgehog-PKA pathway regulates two distinct steps of the differentiation of retinal ganglion cells: the cell-cycle exit of retinoblasts and their neuronal maturation. Development 2005; 132:1539-53. [PMID: 15728672 DOI: 10.1242/dev.01714] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In the developing zebrafish retina, neurogenesis is initiated in cells adjacent to the optic stalk and progresses to the entire neural retina. It has been reported that hedgehog (Hh) signalling mediates the progression of the differentiation of retinal ganglion cells (RGCs) in zebrafish. However, the progression of neurogenesis seems to be only mildly delayed by genetic or chemical blockade of the Hh signalling pathway. Here, we show that cAMP-dependent protein kinase (PKA) effectively inhibits the progression of retinal neurogenesis in zebrafish. Almost all retinal cells continue to proliferate when PKA is activated, suggesting that PKA inhibits the cell-cycle exit of retinoblasts. A cyclin-dependent kinase (cdk) inhibitor p27 inhibits the PKA-induced proliferation, suggesting that PKA functions upstream of cyclins and cdk inhibitors. Activation of the Wnt signalling pathway induces the hyperproliferation of retinal cells in zebrafish. The blockade of Wnt signalling inhibits the PKA-induced proliferation, but the activation of Wnt signalling promotes proliferation even in the absence of PKA activity. These observations suggest that PKA inhibits exit from the Wnt-mediated cell cycle rather than stimulates Wnt-mediated cell-cycle progression. PKA is an inhibitor of Hh signalling, and Hh signalling molecule morphants show severe defects in cell-cycle exit of retinoblasts. Together, these data suggest that Hh acts as a short-range signal to induce the cell-cycle exit of retinoblasts. The pulse inhibition of Hh signalling revealed that Hh signalling regulates at least two distinct steps of RGC differentiation: the cell-cycle exit of retinoblasts and RGC maturation. This dual requirement of Hh signalling in RGC differentiation implies that the regulation of a neurogenic wave is more complex in the zebrafish retina than in the Drosophila eye.
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Affiliation(s)
- Ichiro Masai
- Masai Initiative Research Unit, RIKEN (The Institute of Physical and Chemical Research, Hirosawa, Saitama, Japan.
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24
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Furutani-Seiki M, Wittbrodt J. Medaka and zebrafish, an evolutionary twin study. Mech Dev 2005; 121:629-37. [PMID: 15210172 DOI: 10.1016/j.mod.2004.05.010] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2004] [Accepted: 05/17/2004] [Indexed: 02/08/2023]
Abstract
Comparison of two related species is one of the most successful approaches to decipher general genetic principles in eukaryotes. This is best illustrated in yeast, where the model systems Saccharomyyces. cervisiae and Schizosaccharomyces. pombe have been examined. Powerful forward genetics in both species, species-specific differences in biological features and the phylogenetic distance between the two species, make them well suited for a comparative approach. Recent whole genome sequencing has also facilitated comparative genomics of these simple eukaryotes. It is now possible to go a step further using higher eukaryotes. A duplication of the genome at the base of the teleost radiation, facilitated evolution of almost 25,000 fish species, more than half of all vertebrate species together. Two teleost genetic model systems have emerged in the past few decades: zebrafish, in which large-scale mutagenesis has been successfully performed, and Medaka, a Japanese killifish with a century of history in genetics and now, as reported in this issue, many induced mutations. In this review we will illustrate how comparison of these two model species, Medaka and zebrafish, can reveal conserved and species-specific genetic and molecular mechanisms underlying vertebrate development.
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Affiliation(s)
- Makoto Furutani-Seiki
- SORST, Kondoh research team, Japan Science and Technology Agency (JST), Kyoto, Japan.
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25
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Loosli F, Del Bene F, Quiring R, Rembold M, Martinez-Morales JR, Carl M, Grabher C, Iquel C, Krone A, Wittbrodt B, Winkler S, Sasado T, Morinaga C, Suwa H, Niwa K, Henrich T, Deguchi T, Hirose Y, Iwanami N, Kunimatsu S, Osakada M, Watanabe T, Yasuoka A, Yoda H, Winkler C, Elmasri H, Kondoh H, Furutani-Seiki M, Wittbrodt J. Mutations affecting retina development in Medaka. Mech Dev 2004; 121:703-14. [PMID: 15210178 DOI: 10.1016/j.mod.2004.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2003] [Revised: 02/20/2004] [Accepted: 03/01/2004] [Indexed: 02/03/2023]
Abstract
In a large scale mutagenesis screen of Medaka we identified 60 recessive zygotic mutations that affect retina development. Based on the onset and type of phenotypic abnormalities, the mutants were grouped into five categories: the first includes 11 mutants that are affected in neural plate and optic vesicle formation. The second group comprises 15 mutants that are impaired in optic vesicle growth. The third group includes 18 mutants that are affected in optic cup development. The fourth group contains 13 mutants with defects in retinal differentiation. 12 of these have smaller eyes, whereas one mutation results in enlarged eyes. The fifth group consists of three mutants with defects in retinal pigmentation. The collection of mutants will be used to address the molecular genetic mechanisms underlying vertebrate eye formation.
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Affiliation(s)
- Felix Loosli
- European Molecular Biology Laboratory, Developmental Biology Programme, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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26
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Abstract
The Drosophila eye is a highly ordered epithelial tissue composed of approximately 750 subunits called ommatidia arranged in a reiterated hexagonal pattern. At higher resolution, observation of the constituent photoreceptors, cone cells, and pigment cells of the eye reveals a highly ordered mosaic of amazing regularity. This relatively simple organization belies the repeated requirement for spatially and temporally coordinated inputs from the Hedgehog (Hh), Wingless (Wg), Decapentaplegic (Dpp), JAK-STAT, Notch, and receptor tyrosine kinase (RTK) signaling pathways. This review will discuss how signaling inputs from the Notch and RTK pathways, superimposed on the developmental history of a cell, facilitate context-specific and appropriate cell fate specification decisions in the developing fly eye. Lessons learned from investigating the combinatorial signal integration strategies underlying Drosophila eye development will likely reveal cell-cell communication paradigms relevant to many aspects of invertebrate and mammalian development. Developmental Dynamics 229:162-175, 2004.
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Affiliation(s)
- Matthew G Voas
- Whitehead Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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