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Cha Z, Yin Z, A L, Ge L, Yang J, Huang X, Gao H, Chen X, Feng Z, Mo L, He J, Zhu S, Zhao M, Tao Z, Gu Z, Xu H. Fullerol rescues the light-induced retinal damage by modulating Müller glia cell fate. Redox Biol 2023; 67:102911. [PMID: 37816275 PMCID: PMC10570010 DOI: 10.1016/j.redox.2023.102911] [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: 08/16/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/12/2023] Open
Abstract
Excessive light exposure can damage photoreceptors and lead to blindness. Oxidative stress serves a key role in photo-induced retinal damage. Free radical scavengers have been proven to protect against photo-damaged retinal degeneration. Fullerol, a potent antioxidant, has the potential to protect against ultraviolet-B (UVB)-induced cornea injury by activating the endogenous stem cells. However, its effects on cell fate determination of Müller glia (MG) between gliosis and de-differentiation remain unclear. Therefore, we established a MG lineage-tracing mouse model of light-induced retinal damage to examine the therapeutic effects of fullerol. Fullerol exhibited superior protection against light-induced retinal injury compared to glutathione (GSH) and reduced oxidative stress levels, inhibited gliosis by suppressing the TGF-β pathway, and enhanced the de-differentiation of MG cells. RNA sequencing revealed that transcription candidate pathways, including Nrf2 and Wnt10a pathways, were involved in fullerol-induced neuroprotection. Fullerol-mediated transcriptional changes were validated by qPCR, Western blotting, and immunostaining using mouse retinas and human-derived Müller cell lines MIO-M1 cells, confirming that fullerol possibly modulated the Nrf2, Wnt10a, and TGF-β pathways in MG, which suppressed gliosis and promoted the de-differentiation of MG in light-induced retinal degeneration, indicating its potential in treating retinal diseases.
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Affiliation(s)
- Zhe Cha
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Zhiyuan Yin
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Luodan A
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Lingling Ge
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Junling Yang
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Xiaona Huang
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Hui Gao
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Xia Chen
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Zhou Feng
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Lingyue Mo
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China
| | - Juncai He
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China; Joint Logistics Support Force of Chinese PLA, No. 927 Hospital, Puer 665000, Yunnan, China
| | - Shuang Zhu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100049, China; College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Maoru Zhao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100049, China; College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zui Tao
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China.
| | - Zhanjun Gu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience, Institute of High Energy Physics and National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing, 100049, China; College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Haiwei Xu
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China; Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Southwest Eye Hospital, Southwest Hospital, Chongqing 400038, China.
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Li X, Gordon PJ, Gaynes JA, Fuller AW, Ringuette R, Santiago CP, Wallace V, Blackshaw S, Li P, Levine EM. Lhx2 is a progenitor-intrinsic modulator of Sonic Hedgehog signaling during early retinal neurogenesis. eLife 2022; 11:e78342. [PMID: 36459481 PMCID: PMC9718532 DOI: 10.7554/elife.78342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 11/09/2022] [Indexed: 12/03/2022] Open
Abstract
An important question in organogenesis is how tissue-specific transcription factors interact with signaling pathways. In some cases, transcription factors define the context for how signaling pathways elicit tissue- or cell-specific responses, and in others, they influence signaling through transcriptional regulation of signaling components or accessory factors. We previously showed that during optic vesicle patterning, the Lim-homeodomain transcription factor Lhx2 has a contextual role by linking the Sonic Hedgehog (Shh) pathway to downstream targets without regulating the pathway itself. Here, we show that during early retinal neurogenesis in mice, Lhx2 is a multilevel regulator of Shh signaling. Specifically, Lhx2 acts cell autonomously to control the expression of pathway genes required for efficient activation and maintenance of signaling in retinal progenitor cells. The Shh co-receptors Cdon and Gas1 are candidate direct targets of Lhx2 that mediate pathway activation, whereas Lhx2 directly or indirectly promotes the expression of other pathway components important for activation and sustained signaling. We also provide genetic evidence suggesting that Lhx2 has a contextual role by linking the Shh pathway to downstream targets. Through these interactions, Lhx2 establishes the competence for Shh signaling in retinal progenitors and the context for the pathway to promote early retinal neurogenesis. The temporally distinct interactions between Lhx2 and the Shh pathway in retinal development illustrate how transcription factors and signaling pathways adapt to meet stage-dependent requirements of tissue formation.
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Affiliation(s)
- Xiaodong Li
- Vanderbilt Eye Institute, Vanderbilt University Medical CenterNashvilleUnited States
| | - Patrick J Gordon
- John A. Moran Eye Center, University of UtahSalt Lake CityUnited States
| | - John A Gaynes
- John A. Moran Eye Center, University of UtahSalt Lake CityUnited States
| | - Alexandra W Fuller
- Department of Cell and Developmental Biology, Vanderbilt UniversityNashvilleUnited States
| | - Randy Ringuette
- Cellular and Molecular Medicine, University of OttawaOttawaCanada
| | - Clayton P Santiago
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Valerie Wallace
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health NetworkTorontoCanada
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Pulin Li
- Whitehead Institute of Biomedical Research, Department of Biology, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Edward M Levine
- Vanderbilt Eye Institute, Vanderbilt University Medical CenterNashvilleUnited States
- John A. Moran Eye Center, University of UtahSalt Lake CityUnited States
- Department of Cell and Developmental Biology, Vanderbilt UniversityNashvilleUnited States
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3
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Age- and cell cycle-related expression patterns of transcription factors and cell cycle regulators in Müller glia. Sci Rep 2022; 12:19584. [PMID: 36379991 PMCID: PMC9666513 DOI: 10.1038/s41598-022-23855-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
Abstract
Mammalian Müller glia express transcription factors and cell cycle regulators essential for the function of retinal progenitors, indicating the latent neurogenic capacity; however, the role of these regulators remains unclear. To gain insights into the role of these regulators in Müller glia, we analyzed expression of transcription factors (Pax6, Vsx2 and Nfia) and cell cycle regulators (cyclin D1 and D3) in rodent Müller glia, focusing on their age- and cell cycle-related expression patterns. Expression of Pax6, Vsx2, Nfia and cyclin D3, but not cyclin D1, increased in Müller glia during development. Photoreceptor injury induced cell cycle-associated increase of Vsx2 and cyclin D1, but not Pax6, Nfia, and cyclin D3. In dissociated cultures, cell cycle-associated increase of Pax6 and Vsx2 was observed in Müller glia from P10 mice but not from P21 mice. Nfia levels were highly correlated with EdU incorporation suggesting their activation during S phase progression. Cyclin D1 and D3 were transiently upregulated in G1 phase but downregulated after S phase entry. Our findings revealed previously unknown links between cell cycle progression and regulator protein expression, which likely affect the cell fate decision of proliferating Müller glia.
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Lim S, Kim YJ, Park S, Choi JH, Sung YH, Nishimori K, Kozmik Z, Lee HW, Kim JW. mTORC1-induced retinal progenitor cell overproliferation leads to accelerated mitotic aging and degeneration of descendent Müller glia. eLife 2021; 10:70079. [PMID: 34677125 PMCID: PMC8577849 DOI: 10.7554/elife.70079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 10/17/2021] [Indexed: 01/22/2023] Open
Abstract
Retinal progenitor cells (RPCs) divide in limited numbers to generate the cells comprising vertebrate retina. The molecular mechanism that leads RPC to the division limit, however, remains elusive. Here, we find that the hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) in an RPC subset by deletion of tuberous sclerosis complex 1 (Tsc1) makes the RPCs arrive at the division limit precociously and produce Müller glia (MG) that degenerate from senescence-associated cell death. We further show the hyperproliferation of Tsc1-deficient RPCs and the degeneration of MG in the mouse retina disappear by concomitant deletion of hypoxia-induced factor 1-alpha (Hif1a), which induces glycolytic gene expression to support mTORC1-induced RPC proliferation. Collectively, our results suggest that, by having mTORC1 constitutively active, an RPC divides and exhausts mitotic capacity faster than neighboring RPCs, and thus produces retinal cells that degenerate with aging-related changes.
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Affiliation(s)
- Soyeon Lim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - You-Joung Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Sooyeon Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Ji-Heon Choi
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Young Hoon Sung
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Yonsei, Republic of Korea.,Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Katsuhiko Nishimori
- Department of Obesity and Internal Inflammation; Bioregulation and Pharmacological Medicine, Fukushima Medical University, Fukushima, Japan
| | - Zbynek Kozmik
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Yonsei, Republic of Korea
| | - Jin Woo Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
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5
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Abstract
The vertebrate eye is derived from the neuroepithelium, surface ectoderm, and extracellular mesenchyme. The neuroepithelium forms an optic cup in which the spatial separation of three domains is established, namely, the region of multipotent retinal progenitor cells (RPCs), the ciliary margin zone (CMZ)-which possesses both a neurogenic and nonneurogenic potential-and the optic disk (OD), the interface between the optic stalk and the neuroretina. Here, we show by genetic ablation in the developing optic cup that Meis1 and Meis2 homeobox genes function redundantly to maintain the retinal progenitor pool while they simultaneously suppress the expression of genes characteristic of CMZ and OD fates. Furthermore, we demonstrate that Meis transcription factors bind regulatory regions of RPC-, CMZ-, and OD-specific genes, thus providing a mechanistic insight into the Meis-dependent gene regulatory network. Our work uncovers the essential role of Meis1 and Meis2 as regulators of cell fate competence, which organize spatial territories in the vertebrate eye.
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Bedont JL, Iascone DM, Sehgal A. The Lineage Before Time: Circadian and Nonclassical Clock Influences on Development. Annu Rev Cell Dev Biol 2020; 36:469-509. [PMID: 33021821 PMCID: PMC10826104 DOI: 10.1146/annurev-cellbio-100818-125454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Diverse factors including metabolism, chromatin remodeling, and mitotic kinetics influence development at the cellular level. These factors are well known to interact with the circadian transcriptional-translational feedback loop (TTFL) after its emergence. What is only recently becoming clear, however, is how metabolism, mitosis, and epigenetics may become organized in a coordinated cyclical precursor signaling module in pluripotent cells prior to the onset of TTFL cycling. We propose that both the precursor module and the TTFL module constrain cellular identity when they are active during development, and that the emergence of these modules themselves is a key lineage marker. Here we review the component pathways underlying these ideas; how proliferation, specification, and differentiation decisions in both developmental and adult stem cell populations are or are not regulated by the classical TTFL; and emerging evidence that we propose implies a primordial clock that precedes the classical TTFL and influences early developmental decisions.
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Affiliation(s)
- Joseph Lewis Bedont
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Daniel Maxim Iascone
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Amita Sehgal
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
- The Howard Hughes Medical Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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7
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Core-clock genes Period 1 and 2 regulate visual cascade and cell cycle components during mouse eye development. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194623. [PMID: 32795630 DOI: 10.1016/j.bbagrm.2020.194623] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 08/07/2020] [Accepted: 08/07/2020] [Indexed: 12/16/2022]
Abstract
The retinas from Period 1 (Per1) and Period 2 (Per2) double-mutant mice (Per1-/-Per2Brdm1) display abnormal blue-cone distribution associated with a reduction in cone opsin mRNA and protein levels, up to 1 year of age. To reveal the molecular mechanisms by which Per1 and Per2 control retina development, we analyzed genome-wide gene expression differences between wild-type (WT) and Per1-/-Per2Brdm1 mice across ocular developmental stages (E15, E18 and P3). All clock genes displayed changes in transcript levels along with normal eye development. RNA-Seq data show major gene expression changes between WT and mutant eyes, with the number of differentially expressed genes (DEG) increasing with developmental age. Functional annotation of the genes showed that the most significant changes in expression levels in mutant mice involve molecular pathways relating to circadian rhythm signaling at E15 and E18. At P3, the visual cascade and the cell cycle were respectively higher and lower expressed compared to WT eyes. Overall, our study provides new insights into signaling pathways -phototransduction and cell cycle- controlled by the circadian clock in the eye during development.
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Rueda EM, Hall BM, Hill MC, Swinton PG, Tong X, Martin JF, Poché RA. The Hippo Pathway Blocks Mammalian Retinal Müller Glial Cell Reprogramming. Cell Rep 2020; 27:1637-1649.e6. [PMID: 31067451 PMCID: PMC6521882 DOI: 10.1016/j.celrep.2019.04.047] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 02/04/2019] [Accepted: 04/09/2019] [Indexed: 02/08/2023] Open
Abstract
In response to retinal damage, the Müller glial cells (MGs) of the zebrafish retina have the ability to undergo a cellular reprogramming event in which they enter the cell cycle and divide asymmetrically, thereby producing multipotent retinal progenitors capable of regenerating lost retinal neurons. However, mammalian MGs do not exhibit such a proliferative and regenerative ability. Here, we identify Hippo pathway-mediated repression of the transcription cofactor YAP as a core regulatory mechanism that normally blocks mammalian MG proliferation and cellular reprogramming. MG-specific deletion of Hippo pathway components Lats1 and Lats2, as well as transgenic expression of a Hippo non-responsive form of YAP (YAP5SA), resulted in dramatic Cyclin D1 upregulation, loss of adult MG identity, and attainment of a highly proliferative, progenitor-like cellular state. Our results reveal that mammalian MGs may have latent regenerative capacity that can be stimulated by repressing Hippo signaling. Rueda et al. identify the Hippo pathway as an endogenous molecular mechanism normally preventing mammalian Müller glial reprogramming to a proliferative, progenitor-like state.
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Affiliation(s)
- Elda M Rueda
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Benjamin M Hall
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Matthew C Hill
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Paul G Swinton
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Heart Institute, Cardiomyocyte Renewal Lab, Houston, TX 77030, USA
| | - Xuefei Tong
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - James F Martin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Development, Disease Models and Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA; Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA; Cardiovasular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Texas Heart Institute, Cardiomyocyte Renewal Lab, Houston, TX 77030, USA.
| | - Ross A Poché
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Development, Disease Models and Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA; Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA.
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9
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Sawant OB, Jidigam VK, Fuller RD, Zucaro OF, Kpegba C, Yu M, Peachey NS, Rao S. The circadian clock gene Bmal1 is required to control the timing of retinal neurogenesis and lamination of Müller glia in the mouse retina. FASEB J 2019; 33:8745-8758. [PMID: 31002540 PMCID: PMC6662963 DOI: 10.1096/fj.201801832rr] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 04/02/2019] [Indexed: 12/20/2022]
Abstract
A single pool of multipotent retinal progenitor cells give rise to the diverse cell types within the mammalian retina. Such cellular diversity is due to precise control of various cellular processes like cell specification, proliferation, differentiation, and maturation. Circadian clock genes can control the expression of key regulators of cell cycle progression and therefore can synchronize the cell cycle state of a heterogeneous population of cells. Here we show that the protein encoded by the circadian clock gene brain and muscle arnt-like protein-1 (Bmal1) is expressed in the embryonic retina and is required to regulate the timing of cell cycle exit. Accordingly, loss of Bmal1 during retinal neurogenesis results in increased S-phase entry and delayed cell cycle exit. Disruption in cell cycle kinetics affects the timely generation of the appropriate neuronal population thus leading to an overall decrease in the number of retinal ganglion cells, amacrine cells, and an increase in the number of the late-born type II cone bipolar cells as well as the Müller glia. Additionally, the mislocalized Müller cells are observed in the photoreceptor layer in the Bmal1 conditional mutants. These changes affect the functional integrity of the visual circuitry as we report a significant delay in visual evoked potential implicit time in the retina-specific Bmal1 null animals. Our results demonstrate that Bmal1 is required to maintain the balance between the neural and glial cells in the embryonic retina by coordinating the timing of cell cycle entry and exit. Thus, Bmal1 plays an essential role during retinal neurogenesis affecting both development and function of the mature retina.-Sawant, O. B., Jidigam, V. K., Fuller, R. D., Zucaro, O. F., Kpegba, C., Yu, M., Peachey, N. S., Rao, S. The circadian clock gene Bmal1 is required to control the timing of retinal neurogenesis and lamination of Müller glia in the mouse retina.
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Affiliation(s)
- Onkar B. Sawant
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Vijay K. Jidigam
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Rebecca D. Fuller
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Olivia F. Zucaro
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Cristel Kpegba
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
| | - Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
| | - Neal S. Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Sujata Rao
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA
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10
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Barrasso AP, Wang S, Tong X, Christiansen AE, Larina IV, Poché RA. Live imaging of developing mouse retinal slices. Neural Dev 2018. [PMID: 30219109 DOI: 10.1186/s13064-018-0120-y.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ex vivo, whole-mount explant culture of the rodent retina has proved to be a valuable approach for studying retinal development. In a limited number of recent studies, this method has been coupled to live fluorescent microscopy with the goal of directly observing dynamic cellular events. However, retinal tissue thickness imposes significant technical limitations. To obtain 3-dimensional images with high quality axial resolution, investigators are restricted to specific areas of the retina and require microscopes, such as 2-photon, with a higher level of depth penetrance. Here, we report a retinal live imaging method that is more amenable to a wider array of imaging systems and does not compromise resolution of retinal cross-sectional area. RESULTS Mouse retinal slice cultures were prepared and standard, inverted confocal microscopy was used to generate movies with high quality resolution of retinal cross-sections. To illustrate the ability of this method to capture discrete, physiologically relevant events during retinal development, we imaged the dynamics of the Fucci cell cycle reporter in both wild type and Cyclin D1 mutant retinal progenitor cells (RPCs) undergoing interkinetic nuclear migration (INM). Like previously reported for the zebrafish, mouse RPCs in G1 phase migrated stochastically and exhibited overall basal drift during development. In contrast, mouse RPCs in G2 phase displayed directed, apical migration toward the ventricular zone prior to mitosis. We also determined that Cyclin D1 knockout RPCs in G2 exhibited a slower apical velocity as compared to wild type. These data are consistent with previous IdU/BrdU window labeling experiments on Cyclin D1 knockout RPCs indicating an elongated cell cycle. Finally, to illustrate the ability to monitor retinal neuron differentiation, we imaged early postnatal horizontal cells (HCs). Time lapse movies uncovered specific HC neurite dynamics consistent with previously published data showing an instructive role for transient vertical neurites in HC mosaic formation. CONCLUSIONS We have detailed a straightforward method to image mouse retinal slice culture preparations that, due to its relative ease, extends live retinal imaging capabilities to a more diverse group of scientists. We have also shown that, by using a slice technique, we can achieve excellent lateral resolution, which is advantageous for capturing intracellular dynamics and overall cell movements during retinal development and differentiation.
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Affiliation(s)
- Anthony P Barrasso
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Shang Wang
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xuefei Tong
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Audrey E Christiansen
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Irina V Larina
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Ross A Poché
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, 77030, USA.
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11
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Barrasso AP, Wang S, Tong X, Christiansen AE, Larina IV, Poché RA. Live imaging of developing mouse retinal slices. Neural Dev 2018; 13:23. [PMID: 30219109 PMCID: PMC6139133 DOI: 10.1186/s13064-018-0120-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 09/04/2018] [Indexed: 11/20/2022] Open
Abstract
Background Ex vivo, whole-mount explant culture of the rodent retina has proved to be a valuable approach for studying retinal development. In a limited number of recent studies, this method has been coupled to live fluorescent microscopy with the goal of directly observing dynamic cellular events. However, retinal tissue thickness imposes significant technical limitations. To obtain 3-dimensional images with high quality axial resolution, investigators are restricted to specific areas of the retina and require microscopes, such as 2-photon, with a higher level of depth penetrance. Here, we report a retinal live imaging method that is more amenable to a wider array of imaging systems and does not compromise resolution of retinal cross-sectional area. Results Mouse retinal slice cultures were prepared and standard, inverted confocal microscopy was used to generate movies with high quality resolution of retinal cross-sections. To illustrate the ability of this method to capture discrete, physiologically relevant events during retinal development, we imaged the dynamics of the Fucci cell cycle reporter in both wild type and Cyclin D1 mutant retinal progenitor cells (RPCs) undergoing interkinetic nuclear migration (INM). Like previously reported for the zebrafish, mouse RPCs in G1 phase migrated stochastically and exhibited overall basal drift during development. In contrast, mouse RPCs in G2 phase displayed directed, apical migration toward the ventricular zone prior to mitosis. We also determined that Cyclin D1 knockout RPCs in G2 exhibited a slower apical velocity as compared to wild type. These data are consistent with previous IdU/BrdU window labeling experiments on Cyclin D1 knockout RPCs indicating an elongated cell cycle. Finally, to illustrate the ability to monitor retinal neuron differentiation, we imaged early postnatal horizontal cells (HCs). Time lapse movies uncovered specific HC neurite dynamics consistent with previously published data showing an instructive role for transient vertical neurites in HC mosaic formation. Conclusions We have detailed a straightforward method to image mouse retinal slice culture preparations that, due to its relative ease, extends live retinal imaging capabilities to a more diverse group of scientists. We have also shown that, by using a slice technique, we can achieve excellent lateral resolution, which is advantageous for capturing intracellular dynamics and overall cell movements during retinal development and differentiation. Electronic supplementary material The online version of this article (10.1186/s13064-018-0120-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anthony P Barrasso
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Shang Wang
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xuefei Tong
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Audrey E Christiansen
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Irina V Larina
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Ross A Poché
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, 77030, USA.
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12
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MLL1 is essential for retinal neurogenesis and horizontal inner neuron integrity. Sci Rep 2018; 8:11902. [PMID: 30093671 PMCID: PMC6085291 DOI: 10.1038/s41598-018-30355-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 07/29/2018] [Indexed: 12/19/2022] Open
Abstract
Development of retinal structure and function is controlled by cell type-specific transcription factors and widely expressed co-regulators. The latter includes the mixed-lineage leukemia (MLL) family of histone methyltransferases that catalyze histone H3 lysine 4 di- and tri-methylation associated with gene activation. One such member, MLL1, is widely expressed in the central nervous system including the retina. However, its role in retinal development is unknown. To address this question, we knocked out Mll1 in mouse retinal progenitors, and discovered that MLL1 plays multiple roles in retinal development by regulating progenitor cell proliferation, cell type composition and neuron-glia balance, maintenance of horizontal neurons, and formation of functional synapses between neuronal layers required for visual signal transmission and processing. Altogether, our results suggest that MLL1 is indispensable for retinal neurogenesis and function development, providing a new paradigm for cell type-specific roles of known histone modifying enzymes during CNS tissue development.
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13
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mTORC1 accelerates retinal development via the immunoproteasome. Nat Commun 2018; 9:2502. [PMID: 29950673 PMCID: PMC6021445 DOI: 10.1038/s41467-018-04774-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 04/26/2018] [Indexed: 11/26/2022] Open
Abstract
The numbers and types of cells constituting vertebrate neural tissues are determined by cellular mechanisms that couple neurogenesis to the proliferation of neural progenitor cells. Here we identified a role of mammalian target of rapamycin complex 1 (mTORC1) in the development of neural tissue, showing that it accelerates progenitor cell cycle progression and neurogenesis in mTORC1-hyperactive tuberous sclerosis complex 1 (Tsc1)-deficient mouse retina. We also show that concomitant loss of immunoproteasome subunit Psmb9, which is induced by Stat1 (signal transducer and activator of transcription factor 1), decelerates cell cycle progression of Tsc1-deficient mouse retinal progenitor cells and normalizes retinal developmental schedule. Collectively, our results establish a developmental role for mTORC1, showing that it promotes neural development through activation of protein turnover via a mechanism involving the immunoproteasome. One of the determinants of the neuronal subtype produced from retinal progenitor cells is their proliferative potential. Here the authors show that mTORC1 promotes progenitor cell cycle progression and hence accelerated development in mouse retina through induction of the immunoproteasome which enhances the degradation of cyclins.
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14
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de Almeida-Pereira L, Repossi MG, Magalhães CF, Azevedo RDF, Corrêa-Velloso JDC, Ulrich H, Ventura ALM, Fragel-Madeira L. P2Y 12 but not P2Y 13 Purinergic Receptor Controls Postnatal Rat Retinogenesis In Vivo. Mol Neurobiol 2018; 55:8612-8624. [PMID: 29574630 DOI: 10.1007/s12035-018-1012-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 03/16/2018] [Indexed: 12/16/2022]
Abstract
Adenine nucleotides through P2Y1 receptor stimulation are known to control retinal progenitor cell (RPC) proliferation by modulating expression of the p57KIP2, a cell cycle regulator. However, the role of Gi protein-coupled P2Y12 and P2Y13 receptors also activated by adenine nucleotides in RPC proliferation is still unknown. Gene expression of the purinergic P2Y12 subtype was detected in rat retina during early postnatal days (P0 to P5), while expression levels of P2Y13 were low. Immunohistochemistry assays performed with rat retina on P3 revealed P2Y12 receptor expression in both Ki-67-positive cells in the neuroblastic layer and Ki-67-negative cells in the ganglion cell layer and inner nuclear layer. Nonetheless, P2Y13 receptor expression could not be detected in any stratum of rat retina. Intravitreal injection of PSB 0739 or clopidogrel, both selective P2Y12 receptor antagonists, increased by 20 and 15%, respectively, the number of Ki-67-positive cells following 24 h of exposure. Moreover, the P2Y12 receptor inhibition increased cyclin D1 and decreased p57KIP2 expression. However, there were no changes in the S phase of the cell cycle (BrdU-positive cells) or in mitosis (phospho-histone-H3-positive cells). Interestingly, an increase in the number of cyclin D1/TUNEL-positive cells after treatment with PSB 0739 was observed. These data suggest that activation of P2Y12 receptors is required for the successful exit of RPCs from cell cycle in the postnatal rat retina.
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Affiliation(s)
- Luana de Almeida-Pereira
- Department of Neurobiology, Institute of Biology, Fluminense Federal University, Niterói, Brazil
| | - Marinna Garcia Repossi
- Department of Neurobiology, Institute of Biology, Fluminense Federal University, Niterói, Brazil
| | - Camila Feitosa Magalhães
- Department of Neurobiology, Institute of Biology, Fluminense Federal University, Niterói, Brazil
| | | | | | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | | | - Lucianne Fragel-Madeira
- Department of Neurobiology, Institute of Biology, Fluminense Federal University, Niterói, Brazil.
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15
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Regulation of Stem Cell Properties of Müller Glia by JAK/STAT and MAPK Signaling in the Mammalian Retina. Stem Cells Int 2017; 2017:1610691. [PMID: 28194183 PMCID: PMC5282447 DOI: 10.1155/2017/1610691] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/21/2016] [Indexed: 12/15/2022] Open
Abstract
In humans and other mammals, the neural retina does not spontaneously regenerate, and damage to the retina that kills retinal neurons results in permanent blindness. In contrast to embryonic stem cells, induced pluripotent stem cells, and embryonic/fetal retinal stem cells, Müller glia offer an intrinsic cellular source for regenerative strategies in the retina. Müller glia are radial glial cells within the retina that maintain retinal homeostasis, buffer ion flux associated with phototransduction, and form the blood/retinal barrier within the retina proper. In injured or degenerating retinas, Müller glia contribute to gliotic responses and scar formation but also show regenerative capabilities that vary across species. In the mammalian retina, regenerative responses achieved to date remain insufficient for potential clinical applications. Activation of JAK/STAT and MAPK signaling by CNTF, EGF, and FGFs can promote proliferation and modulate the glial/neurogenic switch. However, to achieve clinical relevance, additional intrinsic and extrinsic factors that restrict or promote regenerative responses of Müller glia in the mammalian retina must be identified. This review focuses on Müller glia and Müller glial-derived stem cells in the retina and phylogenetic differences among model vertebrate species and highlights some of the current progress towards understanding the cellular mechanisms regulating their regenerative response.
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16
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Miles A, Tropepe V. Coordinating progenitor cell cycle exit and differentiation in the developing vertebrate retina. NEUROGENESIS 2016; 3:e1161697. [PMID: 27604453 PMCID: PMC4974023 DOI: 10.1080/23262133.2016.1161697] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 01/09/2016] [Accepted: 02/29/2016] [Indexed: 02/06/2023]
Abstract
The proper development of the vertebrate retina relies heavily on producing the correct number and type of differentiated retinal cell types. To achieve this, proliferating retinal progenitor cells (RPCs) must exit the cell cycle at an appropriate time and correctly express a subset of differentiation markers that help specify retinal cell fate. Homeobox genes, which encode a family of transcription factors, have been accredited to both these processes, implicated in the transcriptional regulation of important cell cycle components, such as cyclins and cyclin-dependent kinases, and proneural genes. This dual regulation of homeobox genes allows these factors to help co-ordinate the transition from the proliferating RPC to postmitotic, differentiated cell. However, understanding the exact molecular targets of these factors remains a challenging task. This commentary highlights the current knowledge we have about how these factors regulate cell cycle progression and differentiation, with particular emphasis on a recent discovery from our lab demonstrating an antagonistic relationship between Vsx2 and Dmbx1 to control RPC proliferation. Future studies should aim to further understand the direct transcriptional targets of these genes, additional co-factors/interacting proteins and the possible recruitment of epigenetic machinery by these homeobox genes.
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Affiliation(s)
- Amanda Miles
- Department of Cell & Systems Biology, University of Toronto , Toronto, Ontario, Canada
| | - Vincent Tropepe
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada; Department of Ophthalmology & Vision Sciences; Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada
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17
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Löffler K, Schäfer P, Völkner M, Holdt T, Karl MO. Age-dependent Müller glia neurogenic competence in the mouse retina. Glia 2015; 63:1809-24. [PMID: 25943952 DOI: 10.1002/glia.22846] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 04/08/2015] [Indexed: 11/10/2022]
Abstract
The mechanisms limiting neuronal regeneration in mammals and their relationship with reactive gliosis are unknown. Müller glia (MG), common to all vertebrate retinas, readily regenerate neuron loss in some species, but normally not in mammals. However, experimental stimulation of limited mammalian retina regeneration has been reported. Here, we use a mouse retina organ culture approach to investigate the MG responses at different mouse ages. We found that MG undergo defined spatio-temporal changes upon stimulation. In EGF-stimulated juvenile postmitotic retinas, most MG upregulate cell-cycle regulators (Mcm6, Pcna, Ki67, Ccnd1) within 48 h ex vivo; some also express the neurogenic factors Ascl1, Pax6, and Vsx2; up to 60% re-enter the cell cycle, some of which delaminate to divide mostly apically; and the majority cease to proliferate after stimulation. A subpopulation of MG progeny starts to express transcription factors (Ptf1a, Nr4a2) and neuronal (Calb1, Calb2, Rbfox3), but not glial, markers, indicating neurogenesis. BrdU-tracking, genetic lineage-tracing, and transgenic-reporter experiments suggest that MG reprogram to a neurogenic stage and proliferate; and that some MG progeny differentiate into neuronal-like cells, most likely amacrines, no photoreceptors; most others remain in a de-differentiated state. The mouse MG regeneration potential becomes restricted, dependent on the age of the animal, as observed by limited activation of the cell cycle and neurogenic factors. The stage-dependent analysis of mouse MG revealed similarities and differences when compared with MG-derived regeneration in fish and chicks. Therefore, the mouse retina ex vivo approach is a potential assay for understanding and overcoming the limitations of mammalian MG-derived neuronal regeneration. Postmitotic MG in mouse retina ex vivo can be stimulated to proliferate, express neurogenic factors, and generate progeny expressing neuronal or glial markers. This potential regenerative competence becomes limited with increasing mouse age.
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Affiliation(s)
- Kati Löffler
- CRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, 01307, Germany
| | - Patrick Schäfer
- CRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, 01307, Germany.,German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, 01307, Germany
| | - Manuela Völkner
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, 01307, Germany
| | - Tina Holdt
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, 01307, Germany
| | - Mike O Karl
- CRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, 01307, Germany.,German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, 01307, Germany
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18
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Heavner WE, Andoniadou CL, Pevny LH. Establishment of the neurogenic boundary of the mouse retina requires cooperation of SOX2 and WNT signaling. Neural Dev 2014; 9:27. [PMID: 25488119 PMCID: PMC4295269 DOI: 10.1186/1749-8104-9-27] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/14/2014] [Indexed: 12/03/2022] Open
Abstract
Background Eye development in vertebrates relies on the critical regulation of SOX2 expression. Humans with mutations in SOX2 often suffer from eye defects including anophthalmia (no eye) and microphthalmia (small eye). In mice, deletion of Sox2 in optic cup progenitor cells results in loss of neural competence and cell fate conversion of the neural retina to a non-neurogenic fate, specifically the acquisition of fate associated with progenitors of the ciliary epithelium. This fate is also promoted with constitutive expression of stabilized β-Catenin in the optic cup, where the WNT pathway is up-regulated. We addressed whether SOX2 co-ordinates the neurogenic boundary of the retina through modulating the WNT/β-Catenin pathway by using a genetic approach in the mouse. Results Upon deletion of Sox2 in the optic cup, response to WNT signaling was expanded, correlating with loss of neural competence, cell fate conversion of the neural retina to ciliary epithelium primordium and, in addition, increased cell cycle time of optic cup progenitors. Removal of Ctnnb1 rescued the cell fate conversion; however, the loss of neural competence and the proliferation defect resulting from lack of SOX2 were not overcome. Lastly, central Sox2-deficient optic cup progenitor cells exhibited WNT-independent up-regulation of D-type Cyclins. Conclusion We propose two distinct roles for SOX2 in the developing retina. Our findings suggest that SOX2 antagonizes the WNT pathway to maintain a neurogenic fate and, in contrast, regulates cycling of optic cup progenitors in a WNT-independent manner. Given that WNT signaling acting upstream of SOX2 has been implicated in the tumorigenicity of embryonic stem cell-derived retinal progenitor cells, our results distinguish the endogenous role of WNT signaling in early optic cup patterning and support a WNT-independent role for SOX2 in maintaining retinal progenitor cell proliferation. Electronic supplementary material The online version of this article (doi:10.1186/1749-8104-9-27) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Whitney E Heavner
- UNC Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA.
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19
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Suga A, Sadamoto K, Fujii M, Mandai M, Takahashi M. Proliferation potential of Müller glia after retinal damage varies between mouse strains. PLoS One 2014; 9:e94556. [PMID: 24747725 PMCID: PMC3991641 DOI: 10.1371/journal.pone.0094556] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 03/18/2014] [Indexed: 01/12/2023] Open
Abstract
Retinal Müller glia can serve as a source for regeneration of damaged retinal neurons in fish, birds and mammals. However, the proliferation rate of Müller glia has been reported to be low in the mammalian retina. To overcome this problem, growth factors and morphogens have been studied as potent promoters of Müller glial proliferation, but the molecular mechanisms that limit the proliferation of Müller glia in the mammalian retina remain unknown. In the present study, we found that the degree of damage-induced Müller glia proliferation varies across mouse strains. In mouse line 129×1/SvJ (129), there was a significantly larger proliferative response compared with that observed in C57BL/6 (B6) after photoreceptor cell death. Treatment with a Glycogen synthase kinase 3 (GSK3) inhibitor enhanced the proliferation of Müller glia in 129 but not in B6 mouse retinas. We therefore focused on the different gene expression patterns during retinal degeneration between B6 and 129. Expression levels of Cyclin D1 and Nestin correlated with the degree of Müller glial proliferation. A comparison of genome-wide gene expression between B6 and 129 showed that distinct sets of genes were upregulated in the retinas after damage, including immune response genes and chromatin remodeling factors.
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Affiliation(s)
- Akiko Suga
- Laboratory for Retinal Regeneration, Center for Developmental Biology, RIKEN, Minatojima, Chu-O-ku, Kobe, Japan
| | - Kazuyo Sadamoto
- Laboratory for Retinal Regeneration, Center for Developmental Biology, RIKEN, Minatojima, Chu-O-ku, Kobe, Japan
| | - Momo Fujii
- Laboratory for Retinal Regeneration, Center for Developmental Biology, RIKEN, Minatojima, Chu-O-ku, Kobe, Japan
| | - Michiko Mandai
- Laboratory for Retinal Regeneration, Center for Developmental Biology, RIKEN, Minatojima, Chu-O-ku, Kobe, Japan
| | - Masayo Takahashi
- Laboratory for Retinal Regeneration, Center for Developmental Biology, RIKEN, Minatojima, Chu-O-ku, Kobe, Japan
- * E-mail:
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20
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Gordon PJ, Yun S, Clark AM, Monuki ES, Murtaugh LC, Levine EM. Lhx2 balances progenitor maintenance with neurogenic output and promotes competence state progression in the developing retina. J Neurosci 2013; 33:12197-207. [PMID: 23884928 PMCID: PMC3721834 DOI: 10.1523/jneurosci.1494-13.2013] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/29/2013] [Accepted: 06/13/2013] [Indexed: 11/21/2022] Open
Abstract
The LIM-Homeodomain transcription factor Lhx2 is an essential organizer of early eye development and is subsequently expressed in retinal progenitor cells (RPCs). To determine its requirement in RPCs, we performed a temporal series of conditional inactivations in mice with the early RPC driver Pax6 α-Cre and the tamoxifen-inducible Hes1(CreERT2) driver. Deletion of Lhx2 caused a significant reduction of the progenitor population and a corresponding increase in neurogenesis. Precursor fate choice correlated with the time of inactivation; early and late inactivation led to the overproduction of retinal ganglion cells (RGCs) and rod photoreceptors, respectively. In each case, however, the overproduction was selective, occurring at the expense of other cell types and indicating a role for Lhx2 in generating cell type diversity. RPCs that persisted in the absence of Lhx2 continued to generate RGC precursors beyond their normal production window, suggesting that Lhx2 facilitates a transition in competence state. These results identify Lhx2 as a key regulator of RPC properties that contribute to the ordered production of multiple cell types during retinal tissue formation.
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Affiliation(s)
- Patrick J. Gordon
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center
- Interdepartmental Program in Neuroscience, and
| | - Sanghee Yun
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center
| | - Anna M. Clark
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center
| | - Edwin S. Monuki
- Department of Pathology and Laboratory Medicine, University of California, Irvine, California 92697
| | - L. Charles Murtaugh
- Department of Human Genetics, University of Utah, Salt Lake City, Utah 84132, and
| | - Edward M. Levine
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center
- Department of Neurobiology and Anatomy
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21
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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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