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Andreazzoli M, Longoni B, Angeloni D, Demontis GC. Retinoid Synthesis Regulation by Retinal Cells in Health and Disease. Cells 2024; 13:871. [PMID: 38786093 PMCID: PMC11120330 DOI: 10.3390/cells13100871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 05/13/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Vision starts in retinal photoreceptors when specialized proteins (opsins) sense photons via their covalently bonded vitamin A derivative 11cis retinaldehyde (11cis-RAL). The reaction of non-enzymatic aldehydes with amino groups lacks specificity, and the reaction products may trigger cell damage. However, the reduced synthesis of 11cis-RAL results in photoreceptor demise and suggests the need for careful control over 11cis-RAL handling by retinal cells. This perspective focuses on retinoid(s) synthesis, their control in the adult retina, and their role during retina development. It also explores the potential importance of 9cis vitamin A derivatives in regulating retinoid synthesis and their impact on photoreceptor development and survival. Additionally, recent advancements suggesting the pivotal nature of retinoid synthesis regulation for cone cell viability are discussed.
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Affiliation(s)
| | - Biancamaria Longoni
- Department of Translational Medicine and New Technologies in Medicine, University of Pisa, 56126 Pisa, Italy
| | - Debora Angeloni
- The Institute of Biorobotics, Scuola Superiore Sant’Anna, 56127 Pisa, Italy
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2
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Martini D, Digregorio M, Voto IAP, Morabito G, Degl'Innocenti A, Giudetti G, Giannaccini M, Andreazzoli M. Kdm7a expression is spatiotemporally regulated in developing Xenopus laevis embryos, and its overexpression influences late retinal development. Dev Dyn 2024; 253:508-518. [PMID: 37909656 DOI: 10.1002/dvdy.670] [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: 06/30/2023] [Revised: 09/26/2023] [Accepted: 10/02/2023] [Indexed: 11/03/2023] Open
Abstract
BACKGROUND Post-translational histone modifications are among the most common epigenetic modifications that orchestrate gene expression, playing a pivotal role during embryonic development and in various pathological conditions. Among histone lysine demethylases, KDM7A, also known as KIAA1718 or JHDM1D, catalyzes the demethylation of H3K9me1/2 and H3K27me1/2, leading to transcriptional regulation. Previous data suggest that KDM7A plays a central role in several biological processes, including cell proliferation, commitment, differentiation, apoptosis, and maintenance. However, information on the expression pattern of KDM7A in whole organisms is limited, and its functional role is still unclear. RESULTS In Xenopus development, kdm7a is expressed early, undergoing spatiotemporal regulation in various organs and tissues, including the central nervous system and the eye. Focusing on retinal development, we found that kdm7a overexpression does not affect the expression of genes critically involved in early neural development and eye-field specification, whereas unbalances the distribution of neural cell subtypes in the mature retina by disfavoring the development of ganglion cells while promoting that of horizontal cells. CONCLUSIONS Kdm7a is dynamically expressed during embryonic development, and its overexpression influences late retinal development, suggesting a potential involvement in the molecular machinery regulating the spatiotemporally ordered generation of retinal neuronal subtypes.
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3
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Andreazzoli M, Barravecchia I, De Cesari C, Angeloni D, Demontis GC. Inducible Pluripotent Stem Cells to Model and Treat Inherited Degenerative Diseases of the Outer Retina: 3D-Organoids Limitations and Bioengineering Solutions. Cells 2021; 10:cells10092489. [PMID: 34572137 PMCID: PMC8471616 DOI: 10.3390/cells10092489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/12/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degenerations (IRD) affecting either photoreceptors or pigment epithelial cells cause progressive visual loss and severe disability, up to complete blindness. Retinal organoids (ROs) technologies opened up the development of human inducible pluripotent stem cells (hiPSC) for disease modeling and replacement therapies. However, hiPSC-derived ROs applications to IRD presently display limited maturation and functionality, with most photoreceptors lacking well-developed outer segments (OS) and light responsiveness comparable to their adult retinal counterparts. In this review, we address for the first time the microenvironment where OS mature, i.e., the subretinal space (SRS), and discuss SRS role in photoreceptors metabolic reprogramming required for OS generation. We also address bioengineering issues to improve culture systems proficiency to promote OS maturation in hiPSC-derived ROs. This issue is crucial, as satisfying the demanding metabolic needs of photoreceptors may unleash hiPSC-derived ROs full potential for disease modeling, drug development, and replacement therapies.
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Affiliation(s)
| | - Ivana Barravecchia
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy;
- Institute of Life Sciences, Scuola Superiore Sant’Anna, 56124 Pisa, Italy;
| | | | - Debora Angeloni
- Institute of Life Sciences, Scuola Superiore Sant’Anna, 56124 Pisa, Italy;
| | - Gian Carlo Demontis
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy;
- Correspondence: (M.A.); (G.C.D.)
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4
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Features of Retinal Neurogenesis as a Key Factor of Age-Related Neurodegeneration: Myth or Reality? Int J Mol Sci 2021; 22:ijms22147373. [PMID: 34298993 PMCID: PMC8303671 DOI: 10.3390/ijms22147373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/05/2021] [Accepted: 07/05/2021] [Indexed: 11/16/2022] Open
Abstract
Age-related macular degeneration (AMD) is a complex multifactorial neurodegenerative disease that constitutes the most common cause of irreversible blindness in the elderly in the developed countries. Incomplete knowledge about its pathogenesis prevents the search for effective methods of prevention and treatment of AMD, primarily of its "dry" type which is by far the most common (90% of all AMD cases). In the recent years, AMD has become "younger": late stages of the disease are now detected in relatively young people. It is known that AMD pathogenesis-according to the age-related structural and functional changes in the retina-is linked with inflammation, hypoxia, oxidative stress, mitochondrial dysfunction, and an impairment of neurotrophic support, but the mechanisms that trigger the conversion of normal age-related changes to the pathological process as well as the reason for early AMD development remain unclear. In the adult mammalian retina, de novo neurogenesis is very limited. Therefore, the structural and functional features that arise during its maturation and formation can exert long-term effects on further ontogenesis of this tissue. The aim of this review was to discuss possible contributions of the changes/disturbances in retinal neurogenesis to the early development of AMD.
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5
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Kha CX, Guerin DJ, Tseng KAS. Studying In Vivo Retinal Progenitor Cell Proliferation in Xenopus laevis. Methods Mol Biol 2020; 2092:19-33. [PMID: 31786778 PMCID: PMC11233400 DOI: 10.1007/978-1-0716-0175-4_2] [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] [Indexed: 03/04/2023]
Abstract
The efficient generation and maintenance of retinal progenitor cells (RPCs) are key goals needed for developing strategies for productive eye repair. Although vertebrate eye development and retinogenesis are well characterized, the mechanisms that can initiate RPC proliferation following injury-induced regrowth and repair remain unknown. This is partly because endogenous RPC proliferation typically occurs during embryogenesis while studies of retinal regeneration have largely utilized adult (or mature) models. We found that embryos of the African clawed frog, Xenopus laevis, successfully regrew functional eyes after ablation. The initiation of regrowth induced a robust RPC proliferative response with a concomitant delay of the endogenous RPC differentiation program. During eye regrowth, overall embryonic development proceeded normally. Here, we provide a protocol to study regrowth-dependent RPC proliferation in vivo. This system represents a robust and low-cost strategy to rapidly define fundamental mechanisms that regulate regrowth-initiated RPC proliferation, which will facilitate progress in identifying promising strategies for productive eye repair.
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Affiliation(s)
- Cindy X Kha
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Dylan J Guerin
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Kelly Ai-Sun Tseng
- School of Life Sciences and Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA.
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6
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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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7
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Mellough CB, Bauer R, Collin J, Dorgau B, Zerti D, Dolan DWP, Jones CM, Izuogu OG, Yu M, Hallam D, Steyn JS, White K, Steel DH, Santibanez-Koref M, Elliott DJ, Jackson MS, Lindsay S, Grellscheid S, Lako M. An integrated transcriptional analysis of the developing human retina. Development 2019; 146:146/2/dev169474. [PMID: 30696714 PMCID: PMC6361134 DOI: 10.1242/dev.169474] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 12/24/2018] [Indexed: 12/11/2022]
Abstract
The scarcity of embryonic/foetal material as a resource for direct study means that there is still limited understanding of human retina development. Here, we present an integrated transcriptome analysis combined with immunohistochemistry in human eye and retinal samples from 4 to 19 post-conception weeks. This analysis reveals three developmental windows with specific gene expression patterns that informed the sequential emergence of retinal cell types and enabled identification of stage-specific cellular and biological processes, and transcriptional regulators. Each stage is characterised by a specific set of alternatively spliced transcripts that code for proteins involved in the formation of the photoreceptor connecting cilium, pre-mRNA splicing and epigenetic modifiers. Importantly, our data show that the transition from foetal to adult retina is characterised by a large increase in the percentage of mutually exclusive exons that code for proteins involved in photoreceptor maintenance. The circular RNA population is also defined and shown to increase during retinal development. Collectively, these data increase our understanding of human retinal development and the pre-mRNA splicing process, and help to identify new candidate disease genes.
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Affiliation(s)
- Carla B. Mellough
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK,Lions Eye Institute, 2 Verdun Street, Nedlands, Perth, WA 6009, Australia
| | - Roman Bauer
- School of Computing, Newcastle University, Newcastle NE4 5TG, UK
| | - Joseph Collin
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Birthe Dorgau
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Darin Zerti
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - David W. P. Dolan
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Carl M. Jones
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Osagie G. Izuogu
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK,European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge CB10 1SD, UK
| | - Min Yu
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Dean Hallam
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Jannetta S. Steyn
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Kathryn White
- EM Research Services, Newcastle University, Newcastle NE2 4HH, UK
| | - David H. Steel
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | | | - David J. Elliott
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Michael S. Jackson
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Susan Lindsay
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Sushma Grellscheid
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
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8
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Ranaei Pirmardan E, Soheili ZS, Samiei S, Ahmadieh H, Mowla SJ, Naseri M, Daftarian N. In Vivo Evaluation of PAX6 Overexpression and NMDA Cytotoxicity to Stimulate Proliferation in the Mouse Retina. Sci Rep 2018; 8:17700. [PMID: 30531887 PMCID: PMC6286369 DOI: 10.1038/s41598-018-35884-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 11/13/2018] [Indexed: 02/08/2023] Open
Abstract
Retinal degenerative diseases, due to the lack of regeneration systems and self-renewable cells, often lead to visual impairment. Pax6 is a pleiotropic transcription factor and its expression level determines self-renewal status or differentiation of retinal cells. Here, we investigated the fate of simultaneous induction of retinal ganglion cell death and Pax6 overexpression in retro-differentiation of retinal cells and their commitment to re-enter into the cell cycle. Induction of acute retinal ganglion cell death and generation of mouse experimental model was performed by N-methyl D-aspartic acid (NMDA) injection. Recombinant AAV2 virus harboring PAX6 cDNA and reporter gene was injected into untreated and model mouse eyes. Histological analyses, including IHC and retinal flatmounts immunostaining were performed. The number of Ki67+ cells was clearly increased in model mice, presumably due to NMDA treatment and regardless of Pax6 over-expression. Unlike previous studies, Ki67+ cells were found in GCL layer and interestingly ONL cells expressed Sox2 stemness marker after NMDA cytotoxicity. The potential of retinal cells for robust Ki67 expression, after injury, and expression of Sox2, confirmed their intrinsic plasticity and made a vivid prospect for retinal regenerative medicine.
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Affiliation(s)
- Ehsan Ranaei Pirmardan
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Zahra-Soheila Soheili
- Department of Molecular Medicine, Institute of Medical Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
| | - Shahram Samiei
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
| | - Hamid Ahmadieh
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Javad Mowla
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Marzieh Naseri
- Department of Molecular Medicine, Faculty of Advanced Technology, Iran University of Medical Sciences, Tehran, Iran
| | - Narsis Daftarian
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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9
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Pérez Saturnino A, Lust K, Wittbrodt J. Notch signalling patterns retinal composition by regulating atoh7 during post-embryonic growth. Development 2018; 145:dev.169698. [PMID: 30337377 PMCID: PMC6240314 DOI: 10.1242/dev.169698] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/09/2018] [Indexed: 01/01/2023]
Abstract
Patterning of a continuously growing naive field in the context of a life-long growing organ such as the teleost eye is of high functional relevance. Intrinsic and extrinsic signals have been proposed to regulate lineage specification in progenitors that exit the stem cell niche in the ciliary marginal zone (CMZ). The proper cell-type composition arising from those progenitors is a prerequisite for retinal function. Our findings in the teleost medaka (Oryzias latipes) uncover that the Notch-Atoh7 axis continuously patterns the CMZ. The complement of cell types originating from the two juxtaposed progenitors marked by Notch or Atoh7 activity contains all constituents of a retinal column. Modulation of Notch signalling specifically in Atoh7-expressing cells demonstrates the crucial role of this axis in generating the correct cell-type proportions. After transiently blocking Notch signalling, retinal patterning and differentiation is re-initiated de novo. Taken together, our data show that Notch activity in the CMZ continuously structures the growing retina by juxtaposing Notch and Atoh7 progenitors that give rise to distinct complementary lineages, revealing coupling of de novo patterning and cell-type specification in the respective lineages. Summary: Mutually exclusive activity of Notch and Atoh7 in the ciliary marginal zone gives rise to two distinct lineages resulting in specification of the full complement of cell types in medaka retina.
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Affiliation(s)
- Alicia Pérez Saturnino
- Centre for Organismal Studies, Heidelberg University, Heidelberg 69120, Germany.,Heidelberg Biosciences International Graduate School (HBIGS), Heidelberg 69120, Germany
| | - Katharina Lust
- Centre for Organismal Studies, Heidelberg University, Heidelberg 69120, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies, Heidelberg University, Heidelberg 69120, Germany
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10
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Pan Y, Kelly LE, El-Hodiri HM. Identification of retinal homeobox (rax) gene-dependent genes by a microarray approach: The DNA endoglycosylase neil3 is a major downstream component of the rax genetic pathway. Dev Dyn 2018; 247:1199-1210. [PMID: 30311321 DOI: 10.1002/dvdy.24679] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/01/2018] [Accepted: 10/01/2018] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND The retinal homeobox (rx/rax) gene is a transcription factor expressed in the developing eye field that is necessary for normal eye development. rax is necessary for retinal specification and stem cell development. The genetic program of early retinal development, including rax expression, can be induced in naïve ectoderm by activation of insulin-like growth factor (IGF) signaling. We have undertaken a microarray-based approach to identify rax-dependent IGF-induced genes. RESULTS We identified 21 IGF-induced genes that exhibit at least a two-fold decrease in expression when rax expression is knocked down. Ten of these genes were expressed in the developing eye, eight were expressed in the ciliary marginal zone of the mature tadpole retina, and four could significantly rescue the rax knockdown phenotype. One of these, the nei endonuclease VIII-like 3 (neil3) gene, rescued the rax knockdown phenotype to a remarkable degree. We found that neil3 is necessary for normal retinal lamination and retinal neuron differentiation. CONCLUSIONS We have identified neil3 as a component of the rax genetic pathway necessary for normal retinal progenitor cell development. neil3 is involved in the base excision DNA repair pathway, suggesting that this pathway is essential for normal rax-dependent progenitor cell development in the mature retina. Developmental Dynamics 247:1199-1210, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Yi Pan
- Center for Molecular and Human Genetics, Nationwide Children's Research Institute, The Ohio State University, Columbus, Ohio
| | - Lisa E Kelly
- Center for Molecular and Human Genetics, Nationwide Children's Research Institute, The Ohio State University, Columbus, Ohio
| | - Heithem M El-Hodiri
- Center for Molecular and Human Genetics, Nationwide Children's Research Institute, The Ohio State University, Columbus, Ohio.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, Ohio
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11
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Conserved characteristics of ocular refractive development - Did the eye evolve once? Exp Eye Res 2018; 183:84-87. [PMID: 29758190 DOI: 10.1016/j.exer.2018.05.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 01/08/2023]
Abstract
It has been speculated that the unitary eyes of vertebrates and molluscs, and the compound eyes of insects and crustaceans, evolved separately. On the other hand, the common use of rhodopsin as a photoreceptor molecule, and the conservation of Pax6 as a master control gene for eye development, suggest instead that the eye evolved once. Yet, recently the molecular genetics that had seemed to suggest a definitive answer to this evolutionary point has once again become cloudy. Here we propose an alternative approach to addressing the question of eye evolution through comparative analyses of physiological optics. Serendipitous discoveries involving form deprivation and defocusing with young monkeys and chicks demonstrated the conserved importance of visual experience on eye development. Similar results have been demonstrated in teleosts, although differences exist in eye anatomy, physiology and optics. In particular, since fish grow throughout life, these effects can also be demonstrated in adults. In comparison, the cephalopod eye is an often-cited example of convergent evolution with the vertebrate eye, although considerable developmental differences exist. Nevertheless, squid eyes from animals raised under alternative lighting exhibit anatomical and refractive changes that agree with those found in vertebrates. Together, these observations provide functional and structural support for the view that the eye evolved once. Because of their very compressed lifespans (only one to two years) cephalopods may be ideal animal models for the study of ocular refractive development.
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12
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Kunst S, Wolloscheck T, Kelleher DK, Wolfrum U, Sargsyan SA, Iuvone PM, Baba K, Tosini G, Spessert R. Pgc-1α and Nr4a1 Are Target Genes of Circadian Melatonin and Dopamine Release in Murine Retina. Invest Ophthalmol Vis Sci 2016; 56:6084-94. [PMID: 26393668 DOI: 10.1167/iovs.15-17503] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
PURPOSE The neurohormones melatonin and dopamine mediate clock-dependent/circadian regulation of inner retinal neurons and photoreceptor cells and in this way promote their functional adaptation to time of day and their survival. To fulfill this function they act on melatonin receptor type 1 (MT1 receptors) and dopamine D4 receptors (D4 receptors), respectively. The aim of the present study was to screen transcriptional regulators important for retinal physiology and/or pathology (Dbp, Egr-1, Fos, Nr1d1, Nr2e3, Nr4a1, Pgc-1α, Rorβ) for circadian regulation and dependence on melatonin signaling/MT1 receptors or dopamine signaling/D4 receptors. METHODS This was done by gene profiling using quantitative polymerase chain reaction in mice deficient in MT1 or D4 receptors. RESULTS The data obtained determined Pgc-1α and Nr4a1 as transcriptional targets of circadian melatonin and dopamine signaling, respectively. CONCLUSIONS The results suggest that Pgc-1α and Nr4a1 represent candidate genes for linking circadian neurohormone release with functional adaptation and healthiness of retina and photoreceptor cells.
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Affiliation(s)
- Stefanie Kunst
- Institute of Functional and Clinical Anatomy University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany 2Department of Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University, Mainz, Germany
| | - Tanja Wolloscheck
- Institute of Functional and Clinical Anatomy University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Debra K Kelleher
- Institute of Functional and Clinical Anatomy University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Uwe Wolfrum
- Department of Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University, Mainz, Germany
| | - S Anna Sargsyan
- Departments of Ophthalmology and Pharmacology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - P Michael Iuvone
- Departments of Ophthalmology and Pharmacology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Kenkichi Baba
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States
| | - Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States
| | - Rainer Spessert
- Institute of Functional and Clinical Anatomy University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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13
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Rué P, Martinez Arias A. Cell dynamics and gene expression control in tissue homeostasis and development. Mol Syst Biol 2015; 11:792. [PMID: 25716053 PMCID: PMC4358661 DOI: 10.15252/msb.20145549] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
During tissue and organ development and maintenance, the dynamic regulation of cellular proliferation and differentiation allows cells to build highly elaborate structures. The development of the vertebrate retina or the maintenance of adult intestinal crypts, for instance, involves the arrangement of newly created cells with different phenotypes, the proportions of which need to be tightly controlled. While some of the basic principles underlying these processes developing and maintaining these organs are known, much remains to be learnt from how cells encode the necessary information and use it to attain those complex but reproducible arrangements. Here, we review the current knowledge on the principles underlying cell population dynamics during tissue development and homeostasis. In particular, we discuss how stochastic fate assignment, cell division, feedback control and cellular transition states interact during organ and tissue development and maintenance in multicellular organisms. We propose a framework, involving the existence of a transition state in which cells are more susceptible to signals that can affect their gene expression state and influence their cell fate decisions. This framework, which also applies to systems much more amenable to quantitative analysis like differentiating embryonic stem cells, links gene expression programmes with cell population dynamics.
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Affiliation(s)
- Pau Rué
- Department of Genetics, University of Cambridge, Cambridge, UK
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14
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Jayakody SA, Gonzalez-Cordero A, Ali RR, Pearson RA. Cellular strategies for retinal repair by photoreceptor replacement. Prog Retin Eye Res 2015; 46:31-66. [PMID: 25660226 DOI: 10.1016/j.preteyeres.2015.01.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 01/13/2015] [Accepted: 01/19/2015] [Indexed: 02/08/2023]
Abstract
Loss of photoreceptors due to retinal degeneration is a major cause of blindness in the developed world. While no effective treatment is currently available, cell replacement therapy, using pluripotent stem cell-derived photoreceptor precursor cells, may be a feasible future treatment. Recent reports have demonstrated rescue of visual function following the transplantation of immature photoreceptors and we have seen major advances in our ability to generate transplantation-competent donor cells from stem cell sources. Moreover, we are beginning to realise the possibilities of using endogenous populations of cells from within the retina itself to mediate retinal repair. Here, we present a review of our current understanding of endogenous repair mechanisms together with recent progress in the use of both ocular and pluripotent stem cells for the treatment of photoreceptor loss. We consider how our understanding of retinal development has underpinned many of the recent major advances in translation and moved us closer to the goal of restoring vision by cellular means.
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Affiliation(s)
- Sujatha A Jayakody
- Gene and Cell Therapy Group, Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1V 9EL, UK
| | - Anai Gonzalez-Cordero
- Gene and Cell Therapy Group, Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1V 9EL, UK
| | - Robin R Ali
- Gene and Cell Therapy Group, Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1V 9EL, UK; NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, City Road, London EC1V 2PD, UK
| | - Rachael A Pearson
- Gene and Cell Therapy Group, Department of Genetics, UCL Institute of Ophthalmology, 11-43 Bath St, London EC1V 9EL, UK.
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15
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Giannaccini M, Giudetti G, Biasci D, Mariotti S, Martini D, Barsacchi G, Andreazzoli M. Brief report: Rx1 defines retinal precursor identity by repressing alternative fates through the activation of TLE2 and Hes4. Stem Cells 2015; 31:2842-7. [PMID: 24038725 DOI: 10.1002/stem.1530] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 07/13/2013] [Accepted: 07/22/2013] [Indexed: 12/25/2022]
Abstract
The molecular mechanisms underlying the acquisition of retinal precursor identity are scarcely defined. Although the homeobox gene Rx1 (also known as Rax) plays a major role in specifying retinal precursors and maintaining their multipotent state, the involved mechanisms remain to be largely deciphered. Here, following a highthroughput screen for genes regulated by Rx1, we found that this transcription factor specifies the fate of retinal progenitors by repressing genes normally activated in adjacent ectodermal territories. Unexpectedly, we also observed that Rx1, mainly through the activation of the transcriptional repressors TLE2 and Hes4, is necessary and sufficient to inhibit endomesodermal gene expression in retinal precursors of the eye field. In particular, Rx1 knockdown leads retinogenic blastomeres to adopt an endomesodermal fate, indicating a previously undescribed function for Rx1 in preventing the expression of endomesoderm determinants known to inhibit retinal fate. Altogether these data suggest that an essential requirement to establish a retinal precursor identity is the active inhibition of pathways leading to alternative fates.
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Affiliation(s)
- Martina Giannaccini
- Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy; Istituto di Scienze della Vita, Scuola Superiore Sant'Anna, Pisa, Italy
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Giudetti G, Giannaccini M, Biasci D, Mariotti S, Degl'innocenti A, Perrotta M, Barsacchi G, Andreazzoli M. Characterization of the Rx1-dependent transcriptome during early retinal development. Dev Dyn 2014; 243:1352-61. [PMID: 24801179 DOI: 10.1002/dvdy.24145] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/29/2014] [Accepted: 05/04/2014] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The transcription factor Rx1, also known as Rax, controls key properties of retinal precursors including migration behavior, proliferation, and maintenance of multipotency. However, Rx1 effector genes are largely unknown. RESULTS To identify genes controlled by Rx1 in early retinal precursors, we compared the transcriptome of Xenopus embryos overexpressing Rx1 to that of embryos in which Rx1 was knocked-down. In particular, we selected 52 genes coherently regulated, i.e., actived in Rx1 gain of function and repressed in Rx1 loss of function experiments, or vice versa. RT-qPCR and in situ hybridization confirmed the trend of regulation predicted by microarray data for the selected genes. Most of the genes upregulated by Rx1 are coexpressed with this transcription factor, while downregulated genes are either not expressed or expressed at very low levels in the early developing retina. Putative direct Rx1 target genes, activated by GR-Rx1 in the absence of protein synthesis, include Ephrin B1 and Sh2d3c, an interactor of ephrinB1 receptor, which represent candidate novel effectors for the migration promoting activity of Rx1. CONCLUSIONS This study identifies previously undescribed Rx1 regulated genes mainly involved in transcription regulation, cell migration/adhesion, and cell proliferation that contribute to delineate the molecular mechanisms underlying Rx1 activities.
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Affiliation(s)
- Guido Giudetti
- Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy
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17
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Unachukwu UJ, Sauane M, Vazquez M, Redenti S. Microfluidic generated EGF-gradients induce chemokinesis of transplantable retinal progenitor cells via the JAK/STAT and PI3kinase signaling pathways. PLoS One 2013; 8:e83906. [PMID: 24376770 PMCID: PMC3871684 DOI: 10.1371/journal.pone.0083906] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 11/10/2013] [Indexed: 11/18/2022] Open
Abstract
A growing number of studies are evaluating retinal progenitor cell (RPC) transplantation as an approach to repair retinal degeneration and restore visual function. To advance cell-replacement strategies for a practical retinal therapy, it is important to define the molecular and biochemical mechanisms guiding RPC motility. We have analyzed RPC expression of the epidermal growth factor receptor (EGFR) and evaluated whether exposure to epidermal growth factor (EGF) can coordinate motogenic activity in vitro. Using Boyden chamber analysis as an initial high-throughput screen, we determined that RPC motility was optimally stimulated by EGF concentrations in the range of 20-400 ng/ml, with decreased stimulation at higher concentrations, suggesting concentration-dependence of EGF-induced motility. Using bioinformatics analysis of the EGF ligand in a retina-specific gene network pathway, we predicted a chemotactic function for EGF involving the MAPK and JAK-STAT intracellular signaling pathways. Based on targeted inhibition studies, we show that ligand binding, phosphorylation of EGFR and activation of the intracellular STAT3 and PI3kinase signaling pathways are necessary to drive RPC motility. Using engineered microfluidic devices to generate quantifiable steady-state gradients of EGF coupled with live-cell tracking, we analyzed the dynamics of individual RPC motility. Microfluidic analysis, including center of mass and maximum accumulated distance, revealed that EGF induced motility is chemokinetic with optimal activity observed in response to low concentration gradients. Our combined results show that EGFR expressing RPCs exhibit enhanced chemokinetic motility in the presence of low nanomole levels of EGF. These findings may serve to inform further studies evaluating the extent to which EGFR activity, in response to endogenous ligand, drives motility and migration of RPCs in retinal transplantation paradigms.
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Affiliation(s)
- Uchenna J. Unachukwu
- Biochemistry Doctoral Program, The Graduate School and University Center, City University of New York, New York, New York, United States of America
| | - Moira Sauane
- Department of Biological Sciences, Herbert Lehman College, City University of New York, Bronx, New York, United States of America
| | - Maribel Vazquez
- Department of Biomedical Engineering, City College of New York, City University of New York, New York, New York, United States of America
| | - Stephen Redenti
- Biochemistry Doctoral Program, The Graduate School and University Center, City University of New York, Department of Biological Sciences, Herbert Lehman College, City University of New York, Bronx, New York, United States of America
- * E-mail:
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18
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Pellissier LP, Alves CH, Quinn PM, Vos RM, Tanimoto N, Lundvig DMS, Dudok JJ, Hooibrink B, Richard F, Beck SC, Huber G, Sothilingam V, Garcia Garrido M, Le Bivic A, Seeliger MW, Wijnholds J. Targeted ablation of CRB1 and CRB2 in retinal progenitor cells mimics Leber congenital amaurosis. PLoS Genet 2013; 9:e1003976. [PMID: 24339791 PMCID: PMC3854796 DOI: 10.1371/journal.pgen.1003976] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 10/09/2013] [Indexed: 01/22/2023] Open
Abstract
Development in the central nervous system is highly dependent on the regulation of the switch from progenitor cell proliferation to differentiation, but the molecular and cellular events controlling this process remain poorly understood. Here, we report that ablation of Crb1 and Crb2 genes results in severe impairment of retinal function, abnormal lamination and thickening of the retina mimicking human Leber congenital amaurosis due to loss of CRB1 function. We show that the levels of CRB1 and CRB2 proteins are crucial for mouse retinal development, as they restrain the proliferation of retinal progenitor cells. The lack of these apical proteins results in altered cell cycle progression and increased number of mitotic cells leading to an increased number of late-born cell types such as rod photoreceptors, bipolar and Müller glia cells in postmitotic retinas. Loss of CRB1 and CRB2 in the retina results in dysregulation of target genes for the Notch1 and YAP/Hippo signaling pathways and increased levels of P120-catenin. Loss of CRB1 and CRB2 result in altered progenitor cell cycle distribution with a decrease in number of late progenitors in G1 and an increase in S and G2/M phase. These findings suggest that CRB1 and CRB2 suppress late progenitor pool expansion by regulating multiple proliferative signaling pathways.
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Affiliation(s)
- Lucie P. Pellissier
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Celso Henrique Alves
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Peter M. Quinn
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Rogier M. Vos
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Naoyuki Tanimoto
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Ditte M. S. Lundvig
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Jacobus J. Dudok
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Berend Hooibrink
- Department of Cell Biology and Histology, Amsterdam Medisch Centrum, Amsterdam, The Netherlands
| | - Fabrice Richard
- Aix-Marseille University, Developmental Biology Institute of Marseille Luminy (IBDML) and CNRS, UMR 6216, Marseille, France
| | - Susanne C. Beck
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Gesine Huber
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Vithiyanjali Sothilingam
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Marina Garcia Garrido
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - André Le Bivic
- Aix-Marseille University, Developmental Biology Institute of Marseille Luminy (IBDML) and CNRS, UMR 6216, Marseille, France
| | - Mathias W. Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Jan Wijnholds
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
- * E-mail:
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Forbes-Osborne MA, Wilson SG, Morris AC. Insulinoma-associated 1a (Insm1a) is required for photoreceptor differentiation in the zebrafish retina. Dev Biol 2013; 380:157-71. [PMID: 23747542 PMCID: PMC3703496 DOI: 10.1016/j.ydbio.2013.05.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 04/29/2013] [Accepted: 05/18/2013] [Indexed: 01/01/2023]
Abstract
The zinc-finger transcription factor insulinoma-associated 1 (Insm1, previously IA-1) is expressed in the developing nervous and neuroendocrine systems, and is required for cell type specific differentiation. Expression of Insm1 is largely absent in the adult, although it is present in neurogenic regions of the adult brain and zebrafish retina. While expression of Insm1 has also been observed in the embryonic retina of numerous vertebrate species, its function during retinal development has remained unexplored. Here, we demonstrate that in the developing zebrafish retina, insm1a is required for photoreceptor differentiation. Insm1a-deficient embryos were microphthalmic and displayed defects in rod and cone photoreceptor differentiation. Rod photoreceptor cells were more sensitive to loss of insm1a expression than were cone photoreceptor cells. Additionally, we provide evidence that insm1a regulates cell cycle progression of retinoblasts, and functions upstream of the bHLH transcription factors ath5/atoh7 and neurod, and the photoreceptor specification genes crx and nr2e3. Finally, we show that insm1a is negatively regulated by Notch-Delta signaling. Taken together, our data demonstrate that Insm1 influences neuronal subtype differentiation during retinal development.
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Affiliation(s)
| | - Stephen G. Wilson
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225
| | - Ann C. Morris
- Department of Biology, University of Kentucky, Lexington, KY 40506-0225
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20
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Lupo G, Novorol C, Smith JR, Vallier L, Miranda E, Alexander M, Biagioni S, Pedersen RA, Harris WA. Multiple roles of Activin/Nodal, bone morphogenetic protein, fibroblast growth factor and Wnt/β-catenin signalling in the anterior neural patterning of adherent human embryonic stem cell cultures. Open Biol 2013; 3:120167. [PMID: 23576785 PMCID: PMC3718331 DOI: 10.1098/rsob.120167] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Several studies have successfully produced a variety of neural cell types from human embryonic stem cells (hESCs), but there has been limited systematic analysis of how different regional identities are established using well-defined differentiation conditions. We have used adherent, chemically defined cultures to analyse the roles of Activin/Nodal, bone morphogenetic protein (BMP), fibroblast growth factor (FGF) and Wnt/β-catenin signalling in neural induction, anteroposterior patterning and eye field specification in hESCs. We show that either BMP inhibition or activation of FGF signalling is required for effective neural induction, but these two pathways have distinct outcomes on rostrocaudal patterning. While BMP inhibition leads to specification of forebrain/midbrain positional identities, FGF-dependent neural induction is associated with strong posteriorization towards hindbrain/spinal cord fates. We also demonstrate that Wnt/β-catenin signalling is activated during neural induction and promotes acquisition of neural fates posterior to forebrain. Therefore, inhibition of this pathway is needed for efficient forebrain specification. Finally, we provide evidence that the levels of Activin/Nodal and BMP signalling have a marked influence on further forebrain patterning and that constitutive inhibition of these pathways represses expression of eye field genes. These results show that the key mechanisms controlling neural patterning in model vertebrate species are preserved in adherent, chemically defined hESC cultures and reveal new insights into the signals regulating eye field specification.
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Affiliation(s)
- Giuseppe Lupo
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
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21
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Das G, Clark AM, Levine EM. Cyclin D1 inactivation extends proliferation and alters histogenesis in the postnatal mouse retina. Dev Dyn 2012; 241:941-52. [PMID: 22434780 DOI: 10.1002/dvdy.23782] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The cell-cycle regulator Cyclin D1 is expressed in embryonic retinal progenitor cells (RPCs) and regulates their cell-cycle rate and neurogenic output. We report here that Cyclin D1 also has important functions in postnatal retinal histogenesis. RESULTS The initial production of Müller glia and bipolar cells was enhanced in Cyclin D1 knockout (Ccnd1(-/-) ) retinas. Despite a steeper than normal rate of depletion of the RPC population at embryonic ages, postnatal Ccnd1(-/-) retinas exhibited an extended window of proliferation, neurogenesis, and gliogenesis. Cyclin D3, normally confined to Müller glia, was prematurely expressed in Ccnd1(-/-) RPCs. However, Cyclin D3 did not compensate for Cyclin D1 in regulating cell-cycle kinetics or neurogenic output. CONCLUSIONS The data presented in this study along with our previous finding that Cyclin D2 was unable to completely compensate for the absence of Cyclin D1 indicate that Cyclin D1 regulates retinal histogenesis in ways not shared by the other D-cyclins.
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Affiliation(s)
- Gaurav Das
- Departments of Ophthalmology and Visual Sciences, and Neurobiology and Anatomy, John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
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22
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Cell fate determination in the vertebrate retina. Trends Neurosci 2012; 35:565-73. [PMID: 22704732 DOI: 10.1016/j.tins.2012.05.004] [Citation(s) in RCA: 213] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 03/26/2012] [Accepted: 05/18/2012] [Indexed: 01/12/2023]
Abstract
The vertebrate retina is a well-characterized and tractable model for studying neurogenesis. Retinal neurons and glia are generated in a conserved sequence from a pool of multipotent progenitor cells, and numerous cell fate determinants for the different classes of retinal cell types have been identified. Here, we summarize several recent developments in the field that have advanced understanding of the regulation of multipotentiality and temporal competence of progenitors. We also discuss recent insights into the relative influence of lineage-based versus stochastic modes of cell fate determination. Enhancing and integrating knowledge of the molecular and genetic machinery underlying retinal development is critically important for understanding not only normal developmental mechanisms, but also therapeutic interventions aimed at restoring vision loss.
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23
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Loss of photoreceptor potential from retinal progenitor cell cultures, despite improvements in survival. Exp Eye Res 2010; 91:500-12. [DOI: 10.1016/j.exer.2010.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 06/29/2010] [Accepted: 07/07/2010] [Indexed: 11/17/2022]
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Tomassy GS, Lodato S, Trayes-Gibson Z, Arlotta P. Development and regeneration of projection neuron subtypes of the cerebral cortex. Sci Prog 2010; 93:151-69. [PMID: 20681320 DOI: 10.3184/003685010x12705764469952] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The idea of repairing damaged neuronal circuitry in the mammalian central nervous system (CNS) has challenged neuroscientists for centuries. This is mainly due to the notorious inability of neurons to regenerate and the unparalleled cellular diversity of the nervous system. In the mammalian cerebral cortex, one of the most complex areas of the CNS, multipotent neural stem and progenitor cells undergo progressive specification during development to generate the staggering variety of projection neuron subtypes that are found in the adult. How is this process orchestrated in the embryo? And, can developmental signals be used to regenerate projection neuron subtypes in the adult or in the dish? Here, we first provide an overview of the diversity and fate potential of neural progenitors of the cerebral cortex during development. Further, we discuss the plasticity of neural progenitors and the roles of intrinsic and extrinsic signals over progenitor fate. Finally, we discuss the relevance of developmental signals for efforts to direct the differentiation of pluripotent stem cells into specific types of cortical projection neurons for therapeutic benefit.
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Xenopus Bsx links daily cell cycle rhythms and pineal photoreceptor fate. Proc Natl Acad Sci U S A 2010; 107:6352-7. [PMID: 20308548 DOI: 10.1073/pnas.1000854107] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In the developing central nervous system, the cell cycle clock plays a crucial role in determining cell fate specification. A second clock, the circadian oscillator, generates daily rhythms of cell cycle progression. Although these two clocks interact, the mechanisms linking circadian cell cycle progression and cell fate determination are still poorly understood. A convenient system to address this issue is the pineal organ of lower vertebrates, which contains only two neuronal types, photoreceptors and projection neurons. In particular, photoreceptors constitute the core of the pineal circadian system, being able to transduce daily light inputs into the rhythmical production of melatonin. However, the genetic program leading to photoreceptor fate largely remains to be deciphered. Here, we report a previously undescribed function for the homeobox gene Bsx in controlling pineal proliferation and photoreceptor fate in Xenopus. We show that Xenopus Bsx (Xbsx) is expressed rhythmically in postmitotic photoreceptor precursors, reaching a peak during the night, with a cycle that is complementary to the daily rhythms of S-phase entry displayed by pineal cells. Xbsx knockdown results in increased night levels of pineal proliferation, whereas activation of a GR-Xbsx protein flattens the daily rhythms of S-phase entry to the lowest level. Furthermore, evidence is presented that Xbsx is necessary and sufficient to promote a photoreceptor fate. Altogether, these data indicate that Xbsx plays a dual role in contributing to shape the profile of the circadian cell cycle progression and in the specification of pineal photoreceptors, thus acting as a unique link between these two events.
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Abstract
The vertebrate eye comprises tissues from different embryonic origins: the lens and the cornea are derived from the surface ectoderm, but the retina and the epithelial layers of the iris and ciliary body are from the anterior neural plate. The timely action of transcription factors and inductive signals ensure the correct development of the different eye components. Establishing the genetic basis of eye defects in zebrafishes, mouse, and human has been an important tool for the detailed analysis of this complex process. A single eye field forms centrally within the anterior neural plate during gastrulation; it is characterized on the molecular level by the expression of "eye-field transcription factors." The single eye field is separated into two, forming the optic vesicle and later (under influence of the lens placode) the optic cup. The lens develops from the lens placode (surface ectoderm) under influence of the underlying optic vesicle. Pax6 acts in this phase as master control gene, and genes encoding cytoskeletal proteins, structural proteins, or membrane proteins become activated. The cornea forms from the surface ectoderm, and cells from the periocular mesenchyme migrate into the cornea giving rise for the future cornea stroma. Similarly, the iris and ciliary body form from the optic cup. The outer layer of the optic cup becomes the retinal pigmented epithelium, and the main part of the inner layer of the optic cup forms later the neural retina with six different types of cells including the photoreceptors. The retinal ganglion cells grow toward the optic stalk forming the optic nerve. This review describes the major molecular players and cellular processes during eye development as they are known from frogs, zebrafish, chick, and mice-showing also differences among species and missing links for future research. The relevance to human disorders is one of the major aspects covered throughout the review.
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Affiliation(s)
- Jochen Graw
- Helmholtz Center Munich-German Research Center for Environmental Health, Institute of Developmental Genetics, Neuherberg, Germany
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