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Salbaum KA, Shelton ER, Serwane F. Retina organoids: Window into the biophysics of neuronal systems. BIOPHYSICS REVIEWS 2022; 3:011302. [PMID: 38505227 PMCID: PMC10903499 DOI: 10.1063/5.0077014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/16/2021] [Indexed: 03/21/2024]
Abstract
With a kind of magnetism, the human retina draws the eye of neuroscientist and physicist alike. It is attractive as a self-organizing system, which forms as a part of the central nervous system via biochemical and mechanical cues. The retina is also intriguing as an electro-optical device, converting photons into voltages to perform on-the-fly filtering before the signals are sent to our brain. Here, we consider how the advent of stem cell derived in vitro analogs of the retina, termed retina organoids, opens up an exploration of the interplay between optics, electrics, and mechanics in a complex neuronal network, all in a Petri dish. This review presents state-of-the-art retina organoid protocols by emphasizing links to the biochemical and mechanical signals of in vivo retinogenesis. Electrophysiological recording of active signal processing becomes possible as retina organoids generate light sensitive and synaptically connected photoreceptors. Experimental biophysical tools provide data to steer the development of mathematical models operating at different levels of coarse-graining. In concert, they provide a means to study how mechanical factors guide retina self-assembly. In turn, this understanding informs the engineering of mechanical signals required to tailor the growth of neuronal network morphology. Tackling the complex developmental and computational processes in the retina requires an interdisciplinary endeavor combining experiment and theory, physics, and biology. The reward is enticing: in the next few years, retina organoids could offer a glimpse inside the machinery of simultaneous cellular self-assembly and signal processing, all in an in vitro setting.
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Affiliation(s)
| | - Elijah R. Shelton
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, Munich, Germany
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2
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Hu X, Li F, He J, Yang J, Jiang Y, Jiang M, Wei D, Chang L, Hejtmancik JF, Hou L, Ma X. LncRNA NEAT1 Recruits SFPQ to Regulate MITF Splicing and Control RPE Cell Proliferation. Invest Ophthalmol Vis Sci 2021; 62:18. [PMID: 34787639 PMCID: PMC8606808 DOI: 10.1167/iovs.62.14.18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Purpose Retinal pigment epithelium (RPE) cell proliferation is precisely regulated to maintain retinal homoeostasis. Microphthalmia-associated transcription factor (MITF), a critical transcription factor in RPE cells, has two alternatively spliced isoforms: (+)MITF and (-)MITF. Previous work has shown that (-)MITF but not (+)MITF inhibits RPE cell proliferation. This study aims to investigate the role of long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in regulating MITF splicing and hence proliferation of RPE cells. Methods Mouse RPE, primary cultured mouse RPE cells, and different proliferative human embryonic stem cell (hESC)-RPE cells were used to evaluate the expression of (+)MITF, (-)MITF, and NEAT1 by reverse-transcription PCR (RT-PCR) or quantitative RT-PCR. NEAT1 was knocked down using specific small interfering RNAs (siRNAs). Splicing factor proline- and glutamine-rich (SFPQ) was overexpressed with the use of lentivirus infection. Cell proliferation was analyzed by cell number counting and Ki67 immunostaining. RNA immunoprecipitation (RIP) was used to analyze the co-binding between the SFPQ and MITF or NEAT1. Results NEAT1 was highly expressed in proliferative RPE cells, which had low expression of (-)MITF. Knockdown of NEAT1 in RPE cells switched the MITF splicing pattern to produce higher levels of (-)MITF and inhibited cell proliferation. Mechanistically, NEAT1 recruited SFPQ to bind directly with MITF mRNA to regulate its alternative splicing. Overexpression of SFPQ in ARPE-19 cells enhanced the binding enrichment of SFPQ to MITF and increased the splicing efficiency of (+)MITF. The binding affinity between SFPQ and MITF was decreased after NEAT1 knockdown. Conclusions NEAT1 acts as a scaffold to recruit SFPQ to MITF mRNA and promote its binding affinity, which plays an important role in regulating the alternative splicing of MITF and RPE cell proliferation.
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Affiliation(s)
- Xiaojuan Hu
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Fang Li
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,Department of Ophthalmology, The First Hospital of Wuhan, Wuhan, China
| | - Junhao He
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Juan Yang
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Ye Jiang
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Mingyuan Jiang
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Dandan Wei
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Lifu Chang
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Ling Hou
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Xiaoyin Ma
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
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3
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Chen Y, Yang J, Geng H, Li L, Li J, Cheng B, Ma X, Li H, Hou L. Photoreceptor degeneration in microphthalmia ( Mitf) mice: partial rescue by pigment epithelium-derived factor. Dis Model Mech 2019; 12:12/1/dmm035642. [PMID: 30651300 PMCID: PMC6361154 DOI: 10.1242/dmm.035642] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 12/04/2018] [Indexed: 12/13/2022] Open
Abstract
Dysfunction and loss of the retinal pigment epithelium (RPE) are hallmarks of retinal degeneration, but the underlying pathogenetic processes are only partially understood. Using mice with a null mutation in the transcription factor gene Mitf, in which RPE deficiencies are associated with retinal degeneration, we evaluated the role of trophic factors secreted by the RPE in retinal homeostasis. In such mice, the thickness of the outer nuclear layer (ONL) is as in wild type up to postnatal day 10, but then is progressively reduced, associated with a marked increase in the number of apoptotic cells and a decline in staining for rhodopsin. We show that retinal degeneration and decrease in rhodopsin staining can be prevented partially in three different ways: first, by recombining mutant-derived postnatal retina with postnatal wild-type RPE in tissue explant cultures; second, by adding to cultured mutant retina the trophic factor pigment epithelium-derived factor (PEDF; also known as SERPINF1), which is normally produced in RPE under the control of Mitf; and third, by treating the eyes of Mitf mutant mice in vivo with drops containing a bioactive PEDF 17-mer peptide. This latter treatment also led to marked increases in a number of rod and cone genes. The results indicate that RPE-derived trophic factors, in particular PEDF, are instrumental in retinal homeostasis, and suggest that PEDF or its bioactive fragments may have therapeutic potential in RPE deficiency-associated retinal degeneration.
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Affiliation(s)
- Yu Chen
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Optometry, Ophthalmology, and Vision Science and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou 325003, China
| | - Juan Yang
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Optometry, Ophthalmology, and Vision Science and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou 325003, China
| | - Huiqin Geng
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Optometry, Ophthalmology, and Vision Science and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou 325003, China
| | - Liping Li
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Optometry, Ophthalmology, and Vision Science and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou 325003, China
| | - Jinyang Li
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Optometry, Ophthalmology, and Vision Science and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou 325003, China
| | - Bing Cheng
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Optometry, Ophthalmology, and Vision Science and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou 325003, China
| | - Xiaoyin Ma
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Optometry, Ophthalmology, and Vision Science and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou 325003, China
| | - Huirong Li
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Optometry, Ophthalmology, and Vision Science and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou 325003, China
| | - Ling Hou
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, State Key Laboratory of Optometry, Ophthalmology, and Vision Science and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou 325003, China
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4
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Bovolenta P, Martinez-Morales JR. Genetics of congenital eye malformations: insights from chick experimental embryology. Hum Genet 2018; 138:1001-1006. [PMID: 29980841 DOI: 10.1007/s00439-018-1900-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 06/26/2018] [Indexed: 12/27/2022]
Abstract
Embryological manipulations in chick embryos have been pivotal in our understanding of many aspects of vertebrate eye formation. This research was particularly important in uncovering the role of tissue interactions as drivers of eye morphogenesis and to dissect the function of critical genes. Here, we have highlighted a few of these past experiments to endorse their value in searching for hitherto unknown causes of rare congenital eye anomalies, such as microphthalmia, anophthalmia and coloboma. We have also highlighted a number of similarities between the chicken and human eye, which might be exploited to address other eye pathologies, including degenerative ocular diseases.
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Affiliation(s)
- Paola Bovolenta
- Centro de Biología Molecular "Severo Ochoa," (CSIC/UAM), 28049, Madrid, Spain.
- CIBERER, ISCIII, 28049, Madrid, Spain.
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5
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Tabata H, Koinui A, Ogura A, Nishihara D, Yamamoto H. A novel nuclear localization signal spans the linker of the two DNA-binding subdomains in the conserved paired domain of Pax6. Genes Genet Syst 2018; 93:75-81. [PMID: 29607880 DOI: 10.1266/ggs.17-00057] [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] [Indexed: 11/23/2022] Open
Abstract
Paired box (Pax) 6, a member of the Pax family of transcription factors, contains two DNA-binding domains, called the paired domain (PD) and the homeodomain (HD), and plays pivotal roles in development of structures such as the eye, central nervous system and pancreas. Pax6 is a major developmental switching molecule because, for example, ectopic expression of the Pax6 gene can induce ectopic whole eye development. Intensive research has been devoted to elucidating the molecular mechanism(s) involved in the function(s) of Pax6, but many issues remain unexplained. One of the important issues is to identify the nuclear localization signal (NLS) in the PD of Pax6, which is predicted to have a stronger NLS activity than that in the HD. We produced expression plasmid constructs that encode the chick Pax6 protein modified to delete the entire PD except for fragments containing putative NLS sequences, and electroporated them in ovo into the developing chick midbrain to define the NLS of the PD. The results show that the NLS in the PD of chick Pax6 consists of an unusually long sequence of 36 amino acid residues. Within this long NLS motif, the central 18 amino acids comprising two consecutive nine-residue segments showed highest NLS activity; this central area corresponds to the C-terminal half of the third α-helix of the PAI subdomain and the subsequent 11 amino acids of a 16-residue linker between PAI and the adjacent RED subdomain. This information helps to elucidate the molecular mechanism by which Pax6 plays a pivotal role during ontogeny.
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Affiliation(s)
- Hiromasa Tabata
- Graduate School of Bioscience, Nagahama Institute of Bio-Science and Technology
| | - Akihiro Koinui
- Graduate School of Bioscience, Nagahama Institute of Bio-Science and Technology
| | - Atsushi Ogura
- Graduate School of Bioscience, Nagahama Institute of Bio-Science and Technology
| | - Daisuke Nishihara
- Graduate School of Bioscience, Nagahama Institute of Bio-Science and Technology.,Graduate School of Life Sciences, Tohoku University
| | - Hiroaki Yamamoto
- Graduate School of Bioscience, Nagahama Institute of Bio-Science and Technology
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6
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Ma X, Hua J, Zheng G, Li F, Rao C, Li H, Wang J, Pan L, Hou L. Regulation of cell proliferation in the retinal pigment epithelium: Differential regulation of the death-associated protein like-1 DAPL1 by alternative MITF splice forms. Pigment Cell Melanoma Res 2017; 31:411-422. [PMID: 29171181 DOI: 10.1111/pcmr.12676] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 11/12/2017] [Indexed: 01/12/2023]
Abstract
Vertebrate eye development and homoeostasis critically depend on the regulation of proliferation of cells forming the retinal pigment epithelium (RPE). Previous results indicated that the death-associated protein like-1 DAPL1 cell autonomously suppresses RPE proliferation in vivo and in vitro. Here, we show in human RPE cell lines that the pigment cell transcription factor MITF regulates RPE cell proliferation by upregulating DAPL1 expression. DAPL1 regulation by MITF is, however, mediated predominantly by (-) MITF, one of two alternative splice isoforms of MITF that lacks six residues located upstream of the DNA-binding basic domain. Furthermore, we find that the regulation of DAPL1 by MITF is indirect in that (-) MITF stimulates the transcription of Musashi homolog-2 (MSI2), which negatively regulates the processing of the anti-DAPL1 microRNA miR-7. Our results provide molecular insights into the regulation of RPE cell proliferation and quiescence and may help us understand the mechanisms of normal RPE maintenance and of eye diseases associated with either RPE hyperproliferation or the lack of regenerative proliferation.
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Affiliation(s)
- Xiaoyin Ma
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | - Jiajia Hua
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Guoxiao Zheng
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Fang Li
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Chunbao Rao
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Huirong Li
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | - Jing Wang
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | - Li Pan
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Ling Hou
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou Medical University, Wenzhou, China
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7
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Ma X, Li H, Wang Y, Wang J, Zheng Q, Hua J, Yang J, Pan L, Lu F, Qu J, Hou L. DAPL1, a susceptibility locus for age-related macular degeneration, acts as a novel suppressor of cell proliferation in the retinal pigment epithelium. Hum Mol Genet 2017; 26:1612-1621. [PMID: 28334846 DOI: 10.1093/hmg/ddx063] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/15/2017] [Indexed: 11/12/2022] Open
Abstract
The retinal pigment epithelium (RPE) forms a monolayer at the back of the vertebrate eye and is fundamental to retinal function and homoeostasis. During early development, RPE cells undergo rapid proliferation, but in the adult, they remain normally nonproliferative throughout life. Nevertheless, under pathological conditions such as in proliferative vitreoretinopathy or after retinal ablation, mature RPE cells can re-enter the cell cycle and form nodules or multiple cell layers. Here we show that Dapl1, whose human homolog represents a susceptibility locus for age-related macular degeneration (AMD), is highly up-regulated in quiescent but not proliferating RPE cells and that experimental overexpression of DAPL1 in proliferating RPE cells inhibits their proliferation. Consistent with this observation, the percent of Ki67-positive cells is significantly higher in E11.5 Dapl1 knockout mouse embryos compared to age-matched controls. In adult Dapl1-/- mice, which survive without showing any overt pathology, RPE overgrowth leads to multiple cell layers and/or cellular nodules. The antiproliferative effect of DAPL1 is associated with an increase in CDKN1A protein levels. Reduction of CDKN1A by siRNA in DAPL1-overexpressing RPE cells in vitro partially restores cell proliferation. Hence, we show that DAPL1 is a novel regulator of RPE cell proliferation that is important for the maintenance of the RPE as a monolayer. The findings suggest that DAPL1 dysregulation may be involved in abnormal RPE-related proliferative diseases and corresponding retinal dysfunctions in humans.
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Affiliation(s)
- Xiaoyin Ma
- Labratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, China.,State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou 325003, China
| | - Huirong Li
- Labratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, China
| | - Yipin Wang
- Labratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, China
| | - Jing Wang
- Labratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, China.,State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou 325003, China
| | - Qinxiang Zheng
- State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou 325003, China
| | - Jiajia Hua
- Labratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, China
| | - Juan Yang
- Labratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, China
| | - Li Pan
- Labratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, China
| | - Fan Lu
- State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou 325003, China
| | - Jia Qu
- State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou 325003, China
| | - Ling Hou
- Labratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, China.,State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology, Wenzhou 325003, China
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8
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Wang J, Liu Y, Su Z, Pan L, Lu F, Qu J, Hou L. The T-Box Transcription Factor TBX2 Regulates Cell Proliferation in the Retinal Pigment Epithelium. Curr Eye Res 2017; 42:1537-1544. [PMID: 28910203 DOI: 10.1080/02713683.2017.1338351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE Vertebrate eye development and function critically depend on the regulation of proliferation of retinal pigment epithelium (RPE) cells. Hence, a thorough analysis of the molecular parameters controlling RPE cell proliferation is crucial for our understanding of the physiology of this cell type both in health and in disease. The T-box transcription factor TBX2 is an important cell cycle regulator in development and oncogenesis, but its specific role in RPE cell proliferation is far from clear. The purpose of the present study is to investigate whether TBX2 plays any role in regulating RPE cell proliferation. MATERIALS AND METHODS The expression of TBX2 in RPE cells was analyzed in wildtype mice and ARPE-19 cells by co-staining for RPE-specific markers and cell proliferation. In vitro, the role of TBX2 was studied by manipulating its levels using RNAi and analyzing the effects on DNA synthesis and cell growth and on gene expression at the RNA and protein levels. RESULTS Here, we find that TBX2 is expressed in RPE cells both in vivo and in vitro. Specific knockdown of TBX2 in the human RPE cell line ARPE-19 leads to an accumulation of cells at G1. This cell cycle arrest is accompanied by changes in the levels of known cell cycle regulators and, in particular, by an increase in the levels of the tumor-suppressor gene CCAAT/enhancer-binding protein delta (CEBPD). In fact, simultaneous knockdown of both TBX2 and CEBPD interferes with the reduction in cell proliferation brought about by TBX2 reduction alone. CONCLUSIONS Our results provide novel insights into the regulatory mechanisms of cell proliferation in the RPE and may contribute to our understanding of normal RPE maintenance and its pathology in degenerative and proliferative disorders of the eye.
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Affiliation(s)
- Jing Wang
- a Laboratory of Developmental Cell Biology and Disease , School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University , Wenzhou , Zhejiang , China.,b State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology , Wenzhou Medical University , Wenzhou , Zhejiang , China
| | - Yin Liu
- a Laboratory of Developmental Cell Biology and Disease , School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University , Wenzhou , Zhejiang , China
| | - Zhongyuan Su
- a Laboratory of Developmental Cell Biology and Disease , School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University , Wenzhou , Zhejiang , China
| | - Li Pan
- a Laboratory of Developmental Cell Biology and Disease , School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University , Wenzhou , Zhejiang , China
| | - Fan Lu
- b State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology , Wenzhou Medical University , Wenzhou , Zhejiang , China
| | - Jia Qu
- b State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology , Wenzhou Medical University , Wenzhou , Zhejiang , China
| | - Ling Hou
- a Laboratory of Developmental Cell Biology and Disease , School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University , Wenzhou , Zhejiang , China.,b State Key Laboratory and Key Laboratory of Vision Science of Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology , Wenzhou Medical University , Wenzhou , Zhejiang , China
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9
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Steinfeld J, Steinfeld I, Bausch A, Coronato N, Hampel ML, Depner H, Layer PG, Vogel-Höpker A. BMP-induced reprogramming of the neural retina into retinal pigment epithelium requires Wnt signalling. Biol Open 2017; 6:979-992. [PMID: 28546339 PMCID: PMC5550904 DOI: 10.1242/bio.018739] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/21/2017] [Indexed: 12/13/2022] Open
Abstract
In vertebrates, the retinal pigment epithelium (RPE) and photoreceptors of the neural retina (NR) comprise a functional unit required for vision. During vertebrate eye development, a conversion of the RPE into NR can be induced by growth factors in vivo at optic cup stages, but the reverse process, the conversion of NR tissue into RPE, has not been reported. Here, we show that bone morphogenetic protein (BMP) signalling can reprogram the NR into RPE at optic cup stages in chick. Shortly after BMP application, expression of Microphthalmia-associated transcription factor (Mitf) is induced in the NR and selective cell death on the basal side of the NR induces an RPE-like morphology. The newly induced RPE differentiates and expresses Melanosomalmatrix protein 115 (Mmp115) and RPE65. BMP-induced Wnt2b expression is observed in regions of the NR that become pigmented. Loss of function studies show that conversion of the NR into RPE requires both BMP and Wnt signalling. Simultaneous to the appearance of ectopic RPE tissue, BMP application reprogrammed the proximal RPE into multi-layered retinal tissue. The newly induced NR expresses visual segment homeobox-containing gene (Vsx2), and the ganglion and photoreceptor cell markers Brn3α and Visinin are detected. Our results show that high BMP concentrations are required to induce the conversion of NR into RPE, while low BMP concentrations can still induce transdifferentiation of the RPE into NR. This knowledge may contribute to the development of efficient standardized protocols for RPE and NR generation for cell replacement therapies.
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Affiliation(s)
- Jörg Steinfeld
- Fachbereich Biologie, Abteilung Stammzell- und Entwicklungsbiologie, Schnittspahnstraße 13, Darmstadt 64287, Germany
| | - Ichie Steinfeld
- Fachbereich Biologie, Abteilung Stammzell- und Entwicklungsbiologie, Schnittspahnstraße 13, Darmstadt 64287, Germany
| | - Alexander Bausch
- Fachbereich Biologie, Abteilung Stammzell- und Entwicklungsbiologie, Schnittspahnstraße 13, Darmstadt 64287, Germany
| | - Nicola Coronato
- Fachbereich Biologie, Abteilung Stammzell- und Entwicklungsbiologie, Schnittspahnstraße 13, Darmstadt 64287, Germany
| | - Meggi-Lee Hampel
- Fachbereich Biologie, Abteilung Stammzell- und Entwicklungsbiologie, Schnittspahnstraße 13, Darmstadt 64287, Germany
| | - Heike Depner
- Fachbereich Biologie, Abteilung Stammzell- und Entwicklungsbiologie, Schnittspahnstraße 13, Darmstadt 64287, Germany
| | - Paul G Layer
- Fachbereich Biologie, Abteilung Stammzell- und Entwicklungsbiologie, Schnittspahnstraße 13, Darmstadt 64287, Germany
| | - Astrid Vogel-Höpker
- Fachbereich Biologie, Abteilung Stammzell- und Entwicklungsbiologie, Schnittspahnstraße 13, Darmstadt 64287, Germany
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10
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Capowski EE, Wright LS, Liang K, Phillips MJ, Wallace K, Petelinsek A, Hagstrom A, Pinilla I, Borys K, Lien J, Min JH, Keles S, Thomson JA, Gamm DM. Regulation of WNT Signaling by VSX2 During Optic Vesicle Patterning in Human Induced Pluripotent Stem Cells. Stem Cells 2016; 34:2625-2634. [PMID: 27301076 DOI: 10.1002/stem.2414] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/28/2016] [Indexed: 12/22/2022]
Abstract
Few gene targets of Visual System Homeobox 2 (VSX2) have been identified despite its broad and critical role in the maintenance of neural retina (NR) fate during early retinogenesis. We performed VSX2 ChIP-seq and ChIP-PCR assays on early stage optic vesicle-like structures (OVs) derived from human iPS cells (hiPSCs), which highlighted WNT pathway genes as direct regulatory targets of VSX2. Examination of early NR patterning in hiPSC-OVs from a patient with a functional null mutation in VSX2 revealed mis-expression and upregulation of WNT pathway components and retinal pigmented epithelium (RPE) markers in comparison to control hiPSC-OVs. Furthermore, pharmacological inhibition of WNT signaling rescued the early mutant phenotype, whereas augmentation of WNT signaling in control hiPSC-OVs phenocopied the mutant. These findings reveal an important role for VSX2 as a regulator of WNT signaling and suggest that VSX2 may act to maintain NR identity at the expense of RPE in part by direct repression of WNT pathway constituents. Stem Cells 2016;34:2625-2634.
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Affiliation(s)
| | - Lynda S Wright
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Kun Liang
- Statistics and Actuarial Science, University of Waterloo, Waterloo, ON, Canada
| | - M Joseph Phillips
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Kyle Wallace
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Anna Petelinsek
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Anna Hagstrom
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Isabel Pinilla
- Aragon Institute for Health Research (IIS Aragón), Lozano Blesa University Hospital, Zaragoza, 50009, Spain.,Department of Ophthalmology, Lozano Blesa University Hospital, Zaragoza, 50009, Spain
| | - Katarzyna Borys
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Jessica Lien
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Jee Hong Min
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Sunduz Keles
- Department of Statistics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | | | - David M Gamm
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53705, USA.,Department of Ophthamology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA
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11
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Oltean A, Huang J, Beebe DC, Taber LA. Tissue growth constrained by extracellular matrix drives invagination during optic cup morphogenesis. Biomech Model Mechanobiol 2016; 15:1405-1421. [PMID: 26984743 DOI: 10.1007/s10237-016-0771-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 02/05/2016] [Indexed: 12/19/2022]
Abstract
In the early embryo, the eyes form initially as relatively spherical optic vesicles (OVs) that protrude from both sides of the brain tube. Each OV grows until it contacts and adheres to the overlying surface ectoderm (SE) via an extracellular matrix (ECM) that is secreted by the SE and OV. The OV and SE then thicken and bend inward (invaginate) to create the optic cup (OC) and lens vesicle, respectively. While constriction of cell apices likely plays a role in SE invagination, the mechanisms that drive OV invagination are poorly understood. Here, we used experiments and computational modeling to explore the hypothesis that the ECM locally constrains the growing OV, forcing it to invaginate. In chick embryos, we examined the need for the ECM by (1) removing SE at different developmental stages and (2) exposing the embryo to collagenase. At relatively early stages of invagination (Hamburger-Hamilton stage HH14[Formula: see text]), removing the SE caused the curvature of the OV to reverse as it 'popped out' and became convex, but the OV remained concave at later stages (HH15) and invaginated further during subsequent culture. Disrupting the ECM had a similar effect, with the OV popping out at early to mid-stages of invagination (HH14[Formula: see text] to HH14[Formula: see text]). These results suggest that the ECM is required for the early stages but not the late stages of OV invagination. Microindentation tests indicate that the matrix is considerably stiffer than the cellular OV, and a finite-element model consisting of a growing spherical OV attached to a relatively stiff layer of ECM reproduced the observed behavior, as well as measured temporal changes in OV curvature, wall thickness, and invagination depth reasonably well. Results from our study also suggest that the OV grows relatively uniformly, while the ECM is stiffer toward the center of the optic vesicle. These results are consistent with our matrix-constraint hypothesis, providing new insight into the mechanics of OC (early retina) morphogenesis.
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Affiliation(s)
- Alina Oltean
- Department of Biomedical Engineering, Washington University, One Brookings Drive, Campus Box 1097, Saint Louis, MO, 63130-4899, USA.
| | - Jie Huang
- Department of Ophthalmology and Visual Sciences, Washington University, Saint Louis, MO, 63130, USA
| | - David C Beebe
- Department of Ophthalmology and Visual Sciences, Washington University, Saint Louis, MO, 63130, USA
| | - Larry A Taber
- Department of Biomedical Engineering, Washington University, One Brookings Drive, Campus Box 1097, Saint Louis, MO, 63130-4899, USA
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12
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Takeda K, Hozumi H, Ohba K, Yamamoto H, Shibahara S. Regional Fluctuation in the Functional Consequence of LINE-1 Insertion in the Mitf Gene: The Black Spotting Phenotype Arisen from the Mitfmi-bw Mouse Lacking Melanocytes. PLoS One 2016; 11:e0150228. [PMID: 26930598 PMCID: PMC4773177 DOI: 10.1371/journal.pone.0150228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/10/2016] [Indexed: 11/19/2022] Open
Abstract
Microphthalmia-associated transcription factor (Mitf) is a key regulator for differentiation of melanoblasts, precursors to melanocytes. The mouse homozygous for the black-eyed white (Mitfmi-bw) allele is characterized by the white-coat color and deafness with black eyes due to the lack of melanocytes. The Mitfmi-bw allele carries LINE-1, a retrotransposable element, which results in the Mitf deficiency. Here, we have established the black spotting mouse that was spontaneously arisen from the homozygous Mitfmi-bw mouse lacking melanocytes. The black spotting mouse shows multiple black patches on the white coat, with age-related graying. Importantly, each black patch also contains hair follicles lacking melanocytes, whereas the white-coat area completely lacks melanocytes. RT-PCR analyses of the pigmented patches confirmed that the LINE-1 insertion is retained in the Mitf gene of the black spotting mouse, thereby excluding the possibility of the somatic reversion of the Mitfmi-bw allele. The immunohistochemical analysis revealed that the staining intensity for beta-catenin was noticeably lower in hair follicles lacking melanocytes of the homozygous Mitfmi-bw mouse and the black spotting mouse, compared to the control mouse. In contrast, the staining intensity for beta-catenin and cyclin D1 was higher in keratinocytes of the black spotting mouse, compared to keratinocytes of the control mouse and the Mitfmi-bw mouse. Moreover, the keratinocyte layer appears thicker in the Mitfmi-bw mouse, with the overexpression of Ki-67, a marker for cell proliferation. We also show that the presumptive black spots are formed by embryonic day 15.5. Thus, the black spotting mouse provides the unique model to explore the molecular basis for the survival and death of developing melanoblasts and melanocyte stem cells in the epidermis. These results indicate that follicular melanocytes are responsible for maintaining the epidermal homeostasis; namely, the present study has provided evidence for the link between melanocyte development and the epidermal microenvironment.
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Affiliation(s)
- Kazuhisa Takeda
- Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Sendai, Miyagi 980–8575, Japan
| | - Hiroki Hozumi
- Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Sendai, Miyagi 980–8575, Japan
| | - Koji Ohba
- Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Sendai, Miyagi 980–8575, Japan
| | - Hiroaki Yamamoto
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526–0829, Japan
| | - Shigeki Shibahara
- Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Sendai, Miyagi 980–8575, Japan
- * E-mail:
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13
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Ohba K, Takeda K, Yamamoto H, Shibahara S. Microphthalmia-associated transcription factor is expressed in projection neurons of the mouse olfactory bulb. Genes Cells 2015; 20:1088-102. [DOI: 10.1111/gtc.12312] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 10/01/2015] [Indexed: 12/11/2022]
Affiliation(s)
- Koji Ohba
- Department of Molecular Biology and Applied Physiology; Tohoku University School of Medicine; 2-1 Seiryo-machi Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Kazuhisa Takeda
- Department of Molecular Biology and Applied Physiology; Tohoku University School of Medicine; 2-1 Seiryo-machi Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Hiroaki Yamamoto
- Faculty of Bioscience; Nagahama Institute of Bio-Science and Technology; 1266 Tamura-cho Nagahama Shiga 526-0829 Japan
| | - Shigeki Shibahara
- Department of Molecular Biology and Applied Physiology; Tohoku University School of Medicine; 2-1 Seiryo-machi Aoba-ku Sendai Miyagi 980-8575 Japan
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14
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Wang X, Xiong K, Lin C, Lv L, Chen J, Xu C, Wang S, Gu D, Zheng H, Yu H, Li Y, Xiao H, Zhou G. New medium used in the differentiation of human pluripotent stem cells to retinal cells is comparable to fetal human eye tissue. Biomaterials 2015; 53:40-9. [DOI: 10.1016/j.biomaterials.2015.02.065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 02/14/2015] [Indexed: 12/29/2022]
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15
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Ma Y, Ding X, Qanbari S, Weigend S, Zhang Q, Simianer H. Properties of different selection signature statistics and a new strategy for combining them. Heredity (Edinb) 2015; 115:426-36. [PMID: 25990878 PMCID: PMC4611237 DOI: 10.1038/hdy.2015.42] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 03/25/2015] [Accepted: 03/31/2015] [Indexed: 12/11/2022] Open
Abstract
Identifying signatures of recent or ongoing selection is of high relevance in livestock population genomics. From a statistical perspective, determining a proper testing procedure and combining various test statistics is challenging. On the basis of extensive simulations in this study, we discuss the statistical properties of eight different established selection signature statistics. In the considered scenario, we show that a reasonable power to detect selection signatures is achieved with high marker density (>1 SNP/kb) as obtained from sequencing, while rather small sample sizes (~15 diploid individuals) appear to be sufficient. Most selection signature statistics such as composite likelihood ratio and cross population extended haplotype homozogysity have the highest power when fixation of the selected allele is reached, while integrated haplotype score has the highest power when selection is ongoing. We suggest a novel strategy, called de-correlated composite of multiple signals (DCMS) to combine different statistics for detecting selection signatures while accounting for the correlation between the different selection signature statistics. When examined with simulated data, DCMS consistently has a higher power than most of the single statistics and shows a reliable positional resolution. We illustrate the new statistic to the established selective sweep around the lactase gene in human HapMap data providing further evidence of the reliability of this new statistic. Then, we apply it to scan selection signatures in two chicken samples with diverse skin color. Our analysis suggests that a set of well-known genes such as BCO2, MC1R, ASIP and TYR were involved in the divergent selection for this trait.
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Affiliation(s)
- Y Ma
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College Animal Science and Technology, China Agricultural University, Beijing, China.,Animal Breeding and Genetics Group, Department of Animal Sciences, Georg-August University, Goettingen, Germany
| | - X Ding
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College Animal Science and Technology, China Agricultural University, Beijing, China
| | - S Qanbari
- Animal Breeding and Genetics Group, Department of Animal Sciences, Georg-August University, Goettingen, Germany
| | - S Weigend
- Institute for Animal Breeding, Federal Agricultural Research Centre, Mariensee, Germany
| | - Q Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, National Engineering Laboratory for Animal Breeding, College Animal Science and Technology, China Agricultural University, Beijing, China
| | - H Simianer
- Animal Breeding and Genetics Group, Department of Animal Sciences, Georg-August University, Goettingen, Germany
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16
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Ovejero-Benito MC, Frade JM. p27(Kip1) participates in the regulation of endoreplication in differentiating chick retinal ganglion cells. Cell Cycle 2015; 14:2311-22. [PMID: 25946375 PMCID: PMC4614947 DOI: 10.1080/15384101.2015.1044175] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Nuclear DNA duplication in the absence of cell division (i.e. endoreplication) leads to somatic polyploidy in eukaryotic cells. In contrast to some invertebrate neurons, whose nuclei may contain up to 200,000-fold the normal haploid DNA amount (C), polyploid neurons in higher vertebrates show only 4C DNA content. To explore the mechanism that prevents extra rounds of DNA synthesis in these latter cells we focused on the chick retina, where a population of tetraploid retinal ganglion cells (RGCs) has been described. We show that differentiating chick RGCs that express the neurotrophic receptors p75 and TrkB while lacking retinoblastoma protein, a feature of tetraploid RGCs, also express p27Kip1. Two different short hairpin RNAs (shRNA) that significantly downregulate p27Kip1 expression facilitated DNA synthesis and increased ploidy in isolated chick RGCs. Moreover, this forced DNA synthesis could not be prevented by Cdk4/6 inhibition, thus suggesting that it is triggered by a mechanism similar to endoreplication. In contrast, p27Kip1 deficiency in mouse RGCs does not lead to increased ploidy despite previous observations have shown ectopic DNA synthesis in RGCs from p27Kip1−/− mice. This suggests that a differential mechanism is used for the regulation of neuronal endoreplication in mammalian versus avian RGCs.
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Affiliation(s)
- María C Ovejero-Benito
- a Department of Molecular , Cellular, and Developmental Neurobiology; Cajal Institute; IC-CSIC ; Madrid , Spain
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17
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Sigulinsky CL, German ML, Leung AM, Clark AM, Yun S, Levine EM. Genetic chimeras reveal the autonomy requirements for Vsx2 in embryonic retinal progenitor cells. Neural Dev 2015; 10:12. [PMID: 25927996 PMCID: PMC4450477 DOI: 10.1186/s13064-015-0039-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 04/14/2015] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Vertebrate retinal development is a complex process, requiring the specification and maintenance of retinal identity, proliferative expansion of retinal progenitor cells (RPCs), and their differentiation into retinal neurons and glia. The homeobox gene Vsx2 is expressed in RPCs and required for the proper execution of this retinal program. However, our understanding of the mechanisms by which Vsx2 does this is still rudimentary. To define the autonomy requirements for Vsx2 in the regulation of RPC properties, we generated chimeric mouse embryos comprised of wild-type and Vsx2-deficient cells. RESULTS We show that Vsx2 maintains retinal identity in part through the cell-autonomous repression of the retinal pigment epithelium determinant Mitf, and that Lhx2 is required cell autonomously for the ectopic Mitf expression in Vsx2-deficient cells. We also found significant cell-nonautonomous contributions to Vsx2-mediated regulation of RPC proliferation, pointing to an important role for Vsx2 in establishing a growth-promoting extracellular environment. Additionally, we report a cell-autonomous requirement for Vsx2 in controlling when neurogenesis is initiated, indicating that Vsx2 is an important mediator of neurogenic competence. Finally, the distribution of wild-type cells shifted away from RPCs and toward retinal ganglion cell precursors in patches of high Vsx2-deficient cell density to potentially compensate for the lack of fated precursors in these areas. CONCLUSIONS Through the generation and analysis of genetic chimeras, we demonstrate that Vsx2 utilizes both cell-autonomous and cell-nonautonomous mechanisms to regulate progenitor properties in the embryonic retina. Importantly, Vsx2's role in regulating Mitf is in part separable from its role in promoting proliferation, and proliferation is excluded as the intrinsic timer that determines when neurogenesis is initiated. These findings highlight the complexity of Vsx2 function during retinal development and provide a framework for identifying the molecular mechanisms mediating these functions.
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Affiliation(s)
- Crystal L Sigulinsky
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Interdepartmental Program in Neuroscience, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Massiell L German
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Amanda M Leung
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Anna M Clark
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Sanghee Yun
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Edward M Levine
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
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18
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Generation of retinal ganglion cells with functional axons from human induced pluripotent stem cells. Sci Rep 2015; 5:8344. [PMID: 25666360 PMCID: PMC4322369 DOI: 10.1038/srep08344] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/15/2015] [Indexed: 12/21/2022] Open
Abstract
We generated self-induced retinal ganglion cells (RGCs) with functional axons from human induced pluripotent stem cells. After development of the optic vesicle from the induced stem cell embryoid body in three-dimensional culture, conversion to two-dimensional culture, achieved by supplementation with BDNF, resulted in differentiation of RGCs at a rate of nearly 90% as indicated by a marginal subregion of an extruded clump of cells, suggesting the formation of an optic vesicle. Axons extended radially from the margin of the clump. Induced RGCs expressed specific markers, such as Brn3b and Math5, as assessed using by quantitative PCR and immunohistochemistry. The long, prominent axons contained neurofilaments and tau and exhibited anterograde axonal transport and sodium-dependent action potentials. The ability to generate RGCs with functional axons uniformly and at a high rate may contribute to both basic and clinical science, including embryology, neurology, pathognomy, and treatment of various optic nerve diseases that threaten vision.
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19
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Wang X, Xiong K, Lu L, Gu D, Wang S, Chen J, Xiao H, Zhou G. Developmental origin of the posterior pigmented epithelium of iris. Cell Biochem Biophys 2014; 71:1067-76. [PMID: 25344647 DOI: 10.1007/s12013-014-0310-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iris epithelium is a double-layered pigmented cuboidal epithelium. According to the current model, the neural retina and the posterior iris pigment epithelium (IPE) are derived from the inner wall of the optic cup, while the retinal pigment epithelium (RPE) and the anterior IPE are derived from the outer wall of the optic cup during development. Our current study shows evidence, contradicting this model of fetal iris development. We demonstrate that human fetal iris expression patterns of Otx2 and Mitf transcription factors are similar, while the expressions of Otx2 and Sox2 are complementary. Furthermore, IPE and RPE exhibit identical morphologic development during the early embryonic period. Our results suggest that the outer layer of the optic cup forms two layers of the iris epithelium, and the posterior IPE is the inward-curling anterior rim of the outer layer of the optic cup. These findings provide a reasonable explanation of how IPE cells can be used as an appropriate substitute for RPE cells.
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Affiliation(s)
- Xiaobing Wang
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
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20
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Capowski EE, Simonett JM, Clark EM, Wright LS, Howden SE, Wallace KA, Petelinsek AM, Pinilla I, Phillips MJ, Meyer JS, Schneider BL, Thomson JA, Gamm DM. Loss of MITF expression during human embryonic stem cell differentiation disrupts retinal pigment epithelium development and optic vesicle cell proliferation. Hum Mol Genet 2014; 23:6332-44. [PMID: 25008112 DOI: 10.1093/hmg/ddu351] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Microphthalmia-associated transcription factor (MITF) is a master regulator of pigmented cell survival and differentiation with direct transcriptional links to cell cycle, apoptosis and pigmentation. In mouse, Mitf is expressed early and uniformly in optic vesicle (OV) cells as they evaginate from the developing neural tube, and null Mitf mutations result in microphthalmia and pigmentation defects. However, homozygous mutations in MITF have not been identified in humans; therefore, little is known about its role in human retinogenesis. We used a human embryonic stem cell (hESC) model that recapitulates numerous aspects of retinal development, including OV specification and formation of retinal pigment epithelium (RPE) and neural retina progenitor cells (NRPCs), to investigate the earliest roles of MITF. During hESC differentiation toward a retinal lineage, a subset of MITF isoforms was expressed in a sequence and tissue distribution similar to that observed in mice. In addition, we found that promoters for the MITF-A, -D and -H isoforms were directly targeted by Visual Systems Homeobox 2 (VSX2), a transcription factor involved in patterning the OV toward a NRPC fate. We then manipulated MITF RNA and protein levels at early developmental stages and observed decreased expression of eye field transcription factors, reduced early OV cell proliferation and disrupted RPE maturation. This work provides a foundation for investigating MITF and other highly complex, multi-purposed transcription factors in a dynamic human developmental model system.
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Affiliation(s)
| | | | | | | | - Sara E Howden
- Morgridge Institute for Research, Madison, WI 53715, USA
| | | | | | - Isabel Pinilla
- Department of Ophthalmology, University Hospital Lozano Blesa, Zaragoza 50009, Spain, Aragon Institute of Health Sciences, Zaragoza 50009, Spain
| | | | - Jason S Meyer
- Department of Biology, Indiana University-Purdue University, Indianapolis, IN 46202, USA
| | - Bernard L Schneider
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - James A Thomson
- Morgridge Institute for Research, Madison, WI 53715, USA, Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53715, USA and Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - David M Gamm
- Waisman Center, McPherson Eye Research Institute and Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA,
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21
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Ou J, Bharti K, Nodari A, Bertuzzi S, Arnheiter H. Vax1/2 genes counteract Mitf-induced respecification of the retinal pigment epithelium. PLoS One 2013; 8:e59247. [PMID: 23555005 PMCID: PMC3598659 DOI: 10.1371/journal.pone.0059247] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 02/13/2013] [Indexed: 01/22/2023] Open
Abstract
During vertebrate eye development, the transcription factor MITF acts to promote the development of the retinal pigment epithelium (RPE). In embryos with Mitf mutations, the future RPE hyperproliferates and is respecified as retinal tissue but only in a small portion of the dorsal RPE. Using a series of genetic crosses, we show that this spatial restriction of RPE respecification is brought about by persistent expression of the anti-retinogenic ventral homeodomain gene Vax2 in the dorso-proximal and both Vax1 and Vax2 in the ventral RPE. We further show that dorso-proximal RPE respecification in Vax2/Mitf double mutants and dorso-proximal and ventral RPE respecification in Vax1/2/Mitf triple mutants result from increased FGF/MAP kinase signaling. In none of the mutants, however, does the distal RPE show signs of hyperproliferation or respecification, likely due to local JAGGED1/NOTCH signaling. Expression studies and optic vesicle culture experiments also suggest a role for NOTCH signaling within the mutant dorsal RPE domains, where ectopic JAGGED1 expression may partially counteract the effects of FGF/ERK1/2 signaling on RPE respecification. The results indicate the presence of complex interplays between distinct transcription factors and signaling molecules during eye development and show how RPE phenotypes associated with mutations in one gene are modulated by expression changes in other genes.
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Affiliation(s)
- Jingxing Ou
- Mammalian Development Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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22
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Nishihara D, Yajima I, Tabata H, Nakai M, Tsukiji N, Katahira T, Takeda K, Shibahara S, Nakamura H, Yamamoto H. Otx2 is involved in the regional specification of the developing retinal pigment epithelium by preventing the expression of sox2 and fgf8, factors that induce neural retina differentiation. PLoS One 2012; 7:e48879. [PMID: 23145006 PMCID: PMC3493611 DOI: 10.1371/journal.pone.0048879] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 10/02/2012] [Indexed: 01/26/2023] Open
Abstract
The retinal pigment epithelium (RPE) shares its developmental origin with the neural retina (NR). When RPE development is disrupted, cells in the presumptive RPE region abnormally differentiate into NR-like cells. Therefore, the prevention of NR differentiation in the presumptive RPE area seems to be essential for regionalizing the RPE during eye development. However, its molecular mechanisms are not fully understood. In this study, we conducted a functional inhibition of a transcription factor Otx2, which is required for RPE development, using early chick embryos. The functional inhibition of Otx2 in chick eyes, using a recombinant gene encoding a dominant negative form of Otx2, caused the outer layer of the optic cup (the region forming the RPE, when embryos normally develop) to abnormally form an ectopic NR. In that ectopic NR, the characteristics of the RPE did not appear and NR markers were ectopically expressed. Intriguingly, the repression of Otx2 function also caused the ectopic expression of Fgf8 and Sox2 in the outer layer of the optic cup (the presumptive RPE region of normally developing eyes). These two factors are known to be capable of inducing NR cell differentiation in the presumptive RPE region, and are not expressed in the normally developing RPE region. Here, we suggest that Otx2 prevents the presumptive RPE region from forming the NR by repressing the expression of both Fgf8 and Sox2 which induce the NR cell fate.
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Affiliation(s)
- Daisuke Nishihara
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Ichiro Yajima
- Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Hiromasa Tabata
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Masato Nakai
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Nagaharu Tsukiji
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Tatsuya Katahira
- Laboratory of Developmental Neurobiology, Graduate School of Brain Science, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Kazuhisa Takeda
- Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Sendai, Miyagi, Japan
| | - Shigeki Shibahara
- Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Sendai, Miyagi, Japan
| | - Harukazu Nakamura
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
- Department of Molecular Neurobiology, Graduate School of Life Sciences and Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, Japan
| | - Hiroaki Yamamoto
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
- * E-mail:
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23
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Zou C, Levine EM. Vsx2 controls eye organogenesis and retinal progenitor identity via homeodomain and non-homeodomain residues required for high affinity DNA binding. PLoS Genet 2012; 8:e1002924. [PMID: 23028343 PMCID: PMC3447932 DOI: 10.1371/journal.pgen.1002924] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 07/05/2012] [Indexed: 12/26/2022] Open
Abstract
The homeodomain and adjacent CVC domain in the visual system homeobox (VSX) proteins are conserved from nematodes to humans. Humans with missense mutations in these regions of VSX2 have microphthalmia, suggesting both regions are critical for function. To assess this, we generated the corresponding mutations in mouse Vsx2. The homeodomain mutant protein lacked DNA binding activity and the knock-in mutant phenocopied the null mutant, ocular retardation J. The CVC mutant protein exhibited weakened DNA binding; and, although the corresponding knock-in allele was recessive, it unexpectedly caused the strongest phenotype, as indicated by severe microphthalmia and hyperpigmentation of the neural retina. This occurred through a cryptic transcriptional feedback loop involving the transcription factors Mitf and Otx1 and the Cdk inhibitor p27Kip1. Our data suggest that the phenotypic severity of the CVC mutant depends on the weakened DNA binding activity elicited by the CVC mutation and a previously unknown protein interaction between Vsx2 and its regulatory target Mitf. Our data also suggest that an essential function of the CVC domain is to assist the homeodomain in high-affinity DNA binding, which is required for eye organogenesis and unhindered execution of the retinal progenitor program in mammals. Finally, the genetic and phenotypic behaviors of the CVC mutation suggest it has the characteristics of a recessive neomorph, a rare type of genetic allele. Problems with the early development of the mammalian retina can cause congenital eye defects such as microphthalmia, in which the eye is dramatically smaller and functionally compromised. Severe microphthalmia is associated with mutations in the retinal-expressed visual system homeobox 2 (Vsx2) gene, but how Vsx2 controls retinal development, and ultimately eye formation, has remained unclear. We assessed the impact of two missense mutations, discovered in humans, on Vsx2 function and eye development in mice. One mutation altered a highly conserved residue of the homeodomain, and the other altered a highly conserved residue in the CVC domain, a region of unresolved function. Both mutations impacted the DNA binding properties of the protein, although to differing extents. Likewise, both mutations caused microphthalmia and disruptions in retinal development, also to differing extents and by distinct mechanisms. Our data suggest that Vsx2 acts as a gatekeeper of the retinal gene expression program by preventing the activation of interfering or competing gene expression programs. We propose that the evolutionary stable association between the VSX-class homeodomain and CVC domain set the stage for Vsx2 or its archetype to assume a gatekeeper function for retinal development and ultimately eye organogenesis.
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Affiliation(s)
- Changjiang Zou
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States of America
| | - Edward M. Levine
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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24
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Adijanto J, Castorino JJ, Wang ZX, Maminishkis A, Grunwald GB, Philp NJ. Microphthalmia-associated transcription factor (MITF) promotes differentiation of human retinal pigment epithelium (RPE) by regulating microRNAs-204/211 expression. J Biol Chem 2012; 287:20491-503. [PMID: 22523078 DOI: 10.1074/jbc.m112.354761] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The retinal pigment epithelium (RPE) plays a fundamental role in maintaining visual function and dedifferentiation of RPE contributes to the pathophysiology of several ocular diseases. To identify microRNAs (miRNAs) that may be involved in RPE differentiation, we compared the miRNA expression profiles of differentiated primary human fetal RPE (hfRPE) cells to dedifferentiated hfRPE cells. We found that miR-204/211, the two most highly expressed miRNAs in the RPE, were significantly down-regulated in dedifferentiated hfRPE cells. Importantly, transfection of pre-miR-204/211 into hfRPE cells promoted differentiation whereas adding miR-204/211 inhibitors led to their dedifferentiation. Microphthalmia-associated transcription factor (MITF) is a key regulator of RPE differentiation that was also down-regulated in dedifferentiated hfRPE cells. MITF knockdown decreased miR-204/211 expression and caused hfRPE dedifferentiation. Significantly, co-transfection of MITF siRNA with pre-miR-204/211 rescued RPE phenotype. Collectively, our data show that miR-204/211 promote RPE differentiation, suggesting that miR-204/211-based therapeutics may be effective treatments for diseases that involve RPE dedifferentiation such as proliferative vitreoretinopathy.
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Affiliation(s)
- Jeffrey Adijanto
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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25
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RAS/RAF/MEK/ERK and PI3K/PTEN/AKT Signaling in Malignant Melanoma Progression and Therapy. Dermatol Res Pract 2011; 2012:354191. [PMID: 22013435 PMCID: PMC3195305 DOI: 10.1155/2012/354191] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 08/09/2011] [Indexed: 01/31/2023] Open
Abstract
Cutaneous malignant melanoma is one of the most serious skin cancers and is highly invasive and markedly resistant to conventional therapy. Melanomagenesis is initially triggered by environmental agents including ultraviolet (UV), which induces genetic/epigenetic alterations in the chromosomes of melanocytes. In human melanomas, the RAS/RAF/MEK/ERK (MAPK) and the PI3K/PTEN/AKT (AKT) signaling pathways are two major signaling pathways and are constitutively activated through genetic alterations. Mutations of RAF, RAS, and PTEN contribute to antiapoptosis, abnormal proliferation, angiogenesis, and invasion for melanoma development and progression. To find better approaches to therapies for patients, understanding these MAPK and AKT signaling mechanisms of melanoma development and progression is important. Here, we review MAPK and AKT signaling networks associated with melanoma development and progression.
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26
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Aruta C, Giordano F, De Marzo A, Comitato A, Raposo G, Nandrot EF, Marigo V. In vitro differentiation of retinal pigment epithelium from adult retinal stem cells. Pigment Cell Melanoma Res 2010; 24:233-40. [PMID: 21232026 DOI: 10.1111/j.1755-148x.2010.00793.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One of the limitations in molecular and functional studies of the retinal pigment epithelium (RPE) has been the lack of an in vitro system retaining all the features of in vivo RPE cells. Retinal pigment epithelium cell lines do not show characteristics typical of a functional RPE, such as pigmentation and expression of specific markers. The present study was aimed at the development of culture conditions to differentiate, in vitro, retinal stem cells (RSC), derived from the adult ciliary body, into a functional RPE. Retinal stem cells were purified from murine eyes, grown as pigmented neurospheres and induced to differentiate into RPE on an extracellular matrix substrate using specific culture conditions. After 7-15 days of culture, pigmented cells with an epithelial morphology showed a polarized organization and a capacity for phagocytosis. We detected different stages of melanogenesis in cells at 7 days of differentiation, whereas RPE at 15 days contained only mature melanosomes. These data suggest that our protocol to differentiate RPE in vitro can provide a useful model for molecular and functional studies.
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Affiliation(s)
- Claudia Aruta
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy
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27
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Avdonin PP, Grigoryan EN, Markitantova YV. Transcriptional factor Pitx2: Localization during triton retina regeneration. BIOL BULL+ 2010. [DOI: 10.1134/s1062359010030039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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28
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Vinuesa CG, Rigby RJ, Yu D. Logic and extent of miRNA-mediated control of autoimmune gene expression. Int Rev Immunol 2009; 28:112-38. [PMID: 19811318 DOI: 10.1080/08830180902934909] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Over the past few decades, multiple mechanisms have emerged that operate to prune the lymphocyte repertoire of self-reactive specificities and maintain immunological tolerance. Multiple families of small noncoding RNAs known as microRNAs (miRNAs) target immune transcripts to fine-tune gene expression and turn on negative feedback loops. Both of these actions are crucial to limit co-stimulation, set precise cellular activation thresholds, curtail inflammation, control lymphocyte growth, and maintain regulatory T cell homeostasis and suppressive function. Analysis of predicted miRNA-mediated regulation of 72 lupus susceptibility genes in humans and mice reveals most contain numerous target sites for over 140 miRNAs conserved in mammals. MECP2, ROQUIN/RC3H1, BCL2, BIM, and PTEN contain over 50 miRNA target sites each, highlighting the need to control their final protein products with enormous precision to maintain the balance between immunity and tolerance. Overlap among targets of individual miRNAs is considerable, with each miRNA targeting a median of nine autoimmune genes. Three miRNAs--miR-181, miR-186, and miR-590-3p--together are predicted to target over 50% of all lupus genes. Also, a single miRNA cluster located at 14q32.31 containing 11 miRNAs is predicted to regulate 48 lupus susceptibility genes. Dysregulation of single or a few miRNAs or miRNA clusters can result from genetic variation, hormonal influences, or environmental triggers including EBV infection. In the light of this vast and promiscuous miRNA-mediated regulation of autoimmune genes it is anticipated that changes in miRNA levels or their target sequences will help explain susceptibility to complex autoimmune diseases.
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Affiliation(s)
- Carola G Vinuesa
- John Curtin School of Medical Research, Australian National University, Canberra, Australia.
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29
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Sengupta N, Caballero S, Sullivan SM, Chang LJ, Afzal A, Li Calzi S, Kielczewski JL, Prabarakan S, Ellis EA, Moldovan L, Moldovan NI, Boulton ME, Grant MB, Scott EW, Harris JR. Regulation of adult hematopoietic stem cells fate for enhanced tissue-specific repair. Mol Ther 2009; 17:1594-604. [PMID: 19584817 PMCID: PMC2835259 DOI: 10.1038/mt.2009.145] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 06/01/2009] [Indexed: 12/29/2022] Open
Abstract
The ability to control the differentiation of adult hematopoietic stem cells (HSCs) would promote development of new cell-based therapies to treat multiple degenerative diseases. Systemic injection of NaIO(3) was used to ablate the retinal pigment epithelial (RPE) layer in C57Bl6 mice and initiate neural retinal degeneration. HSCs infected ex vivo with lentiviral vector expressing the RPE-specific gene RPE65 restored a functional RPE layer, with typical RPE phenotype including coexpression of another RPE-specific marker, CRALBP, and photoreceptor outer segment phagocytosis. Retinal degeneration was prevented and visual function, as measured by electroretinography (ERG), was restored to levels similar to that found in normal animals. None of the controls (no HSCs, HSCs alone and HSCs infected with lentiviral vector expressing LacZ) showed these effects. In vitro gene array studies demonstrated that infection of HSC with RPE65 increased adenylate cyclase mRNA. In vitro exposure of HSCs to a pharmacological agonist of adenylate cyclase also led to in vitro differentiation of HSCs to RPE-like cells expressing pigment granules and the RPE-specific marker, CRALBP. Our data confirm that expression of the cell-specific gene RPE65 promoted fate determination of HSCs toward RPE for targeted tissue repair, and did so in part by activation of adenylate cyclase signaling pathways. Expression by HSCs of single genes unique to a differentiated cell may represent a novel experimental paradigm to influence HSC plasticity, force selective differentiation, and ultimately lead to identification of pharmacological alternatives to viral gene delivery.
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Affiliation(s)
- Nilanjana Sengupta
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida 32610-0267, USA
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30
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Ishii Y, Weinberg K, Oda-Ishii I, Coughlin L, Mikawa T. Morphogenesis and cytodifferentiation of the avian retinal pigmented epithelium require downregulation of Group B1 Sox genes. Development 2009; 136:2579-89. [PMID: 19570849 DOI: 10.1242/dev.031344] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The optic vesicle is a multipotential primordium of the retina, which becomes subdivided into the neural retina and retinal pigmented epithelium domains. Although the roles of several paracrine factors in patterning the optic vesicle have been studied extensively, little is known about cell-autonomous mechanisms that regulate coordinated cell morphogenesis and cytodifferentiation of the retinal pigmented epithelium. Here we demonstrate that members of the SoxB1 gene family, Sox1, Sox2 and Sox3, are all downregulated in the presumptive retinal pigmented epithelium. Constitutive maintenance of SoxB1 expression in the presumptive retinal pigmented epithelium both in vivo and in vitro resulted in the absence of cuboidal morphology and pigmentation, and in concomitant induction of neural differentiation markers. We also demonstrate that exogenous Fgf4 inhibits downregulation all SoxB1 family members in the presumptive retinal pigment epithelium. These results suggest that retinal pigment epithelium morphogenesis and cytodifferentiation requires SoxB1 downregulation, which depends on the absence of exposure to an FGF-like signal.
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Affiliation(s)
- Yasuo Ishii
- University of California San Francisco, Cardiovascular Research Institute, Rock Hall Room 384D, San Francisco, CA 94158, USA
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