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Fu C, Yang N, Chuang JZ, Nakajima N, Iraha S, Roy N, Wu Z, Jiang Z, Otsu W, Radu RA, Yang HH, Lee MP, Worgall TS, Xiong WC, Sung CH. Mutant mice with rod-specific VPS35 deletion exhibit retinal α-synuclein pathology-associated degeneration. Nat Commun 2024; 15:5970. [PMID: 39043666 PMCID: PMC11266608 DOI: 10.1038/s41467-024-50189-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 06/28/2024] [Indexed: 07/25/2024] Open
Abstract
Vacuolar protein sorting 35 (VPS35), the core component of the retromer complex which regulates endosomal trafficking, is genetically linked with Parkinson's disease (PD). Impaired vision is a common non-motor manifestation of PD. Here, we show mouse retinas with VPS35-deficient rods exhibit synapse loss and visual deficit, followed by progressive degeneration concomitant with the emergence of Lewy body-like inclusions and phospho-α-synuclein (P-αSyn) aggregation. Ultrastructural analyses reveal VPS35-deficient rods accumulate aggregates in late endosomes, deposited as lipofuscins bound to P-αSyn. Mechanistically, we uncover a protein network of VPS35 and its interaction with HSC70. VPS35 deficiency promotes sequestration of HSC70 and P-αSyn aggregation in late endosomes. Microglia which engulf lipofuscins and P-αSyn aggregates are activated, displaying autofluorescence, observed as bright dots in fundus imaging of live animals, coinciding with pathology onset and progression. The Rod∆Vps35 mouse line is a valuable tool for further mechanistic investigation of αSyn lesions and retinal degenerative diseases.
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Affiliation(s)
- Cheng Fu
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Nan Yang
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Jen-Zen Chuang
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Nobuyuki Nakajima
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
- Department of Urology, Tokai University School of Medicipne, Tokyo, Japan
| | - Satoshi Iraha
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
- Department of Ophthalmology, Faculty of Life Sciences, Kumamoto University; Department of Ophthalmology, National Sanatorium Kikuchi Keifuen, Kumamoto, Japan
| | - Neeta Roy
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Zhenquan Wu
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Zhichun Jiang
- UCLA Stein Eye Institute, and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Wataru Otsu
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
- Department of Biomedical Research Laboratory, Gifu Pharmaceutical University, Gifu, Japan
| | - Roxana A Radu
- UCLA Stein Eye Institute, and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Howard Hua Yang
- The Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Maxwell Ping Lee
- The Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Tilla S Worgall
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Wen-Cheng Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Ching-Hwa Sung
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
- Department of Cell and Developmental Biology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
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Chen D, Keremane S, Wang S, Lei EP. CTCF regulates global chromatin accessibility and transcription during rod photoreceptor development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.27.596084. [PMID: 38853900 PMCID: PMC11160664 DOI: 10.1101/2024.05.27.596084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Chromatin architecture facilitates accurate transcription at a number of loci, but it remains unclear how much chromatin architecture is involved in global transcriptional regulation. Previous work has shown that rapid depletion of the architectural protein CTCF in cell culture strongly alters chromatin organization but results in surprisingly limited gene expression changes. This discrepancy has also been observed when other architectural proteins are depleted, and one possible explanation is that full transcriptional changes are masked by cellular heterogeneity. We tested this idea by performing multi-omics analyses with sorted post-mitotic mouse rods, which undergo synchronized development, and identified CTCF-dependent regulation of global chromatin accessibility and gene expression. Depletion of CTCF leads to dysregulation of ∼20% of the entire transcriptome (>3,000 genes) and ∼41% of genome accessibility (>26,000 sites), and these regions are strongly enriched in euchromatin. Importantly, these changes are highly enriched for CTCF occupancy, suggesting direct CTCF binding and transcriptional regulation at these active loci. CTCF mainly promotes chromatin accessibility of these direct binding targets, and a large fraction of these sites correspond to promoters. At these sites, CTCF binding frequently promotes accessibility and inhibits expression, and motifs of transcription repressors are found to be significantly enriched. Our findings provide different and often opposite conclusions from previous studies, emphasizing the need to consider cell heterogeneity and cell type specificity when performing multi-omics analyses. We conclude that the architectural protein CTCF binds chromatin and regulates global chromatin accessibility and transcription during rod development.
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Conedera FM, Kokona D, Zinkernagel MS, Stein JV, Lin CP, Alt C, Enzmann V. Macrophages coordinate immune response to laser-induced injury via extracellular traps. J Neuroinflammation 2024; 21:68. [PMID: 38500151 PMCID: PMC10949579 DOI: 10.1186/s12974-024-03064-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/13/2024] [Indexed: 03/20/2024] Open
Abstract
BACKGROUND Retinal degeneration results from disruptions in retinal homeostasis due to injury, disease, or aging and triggers peripheral leukocyte infiltration. Effective immune responses rely on coordinated actions of resident microglia and recruited macrophages, critical for tissue remodeling and repair. However, these phagocytes also contribute to chronic inflammation in degenerated retinas, yet the precise coordination of immune response to retinal damage remains elusive. Recent investigations have demonstrated that phagocytic cells can produce extracellular traps (ETs), which are a source of self-antigens that alter the immune response, which can potentially lead to tissue injury. METHODS Innovations in experimental systems facilitate real-time exploration of immune cell interactions and dynamic responses. We integrated in vivo imaging with ultrastructural analysis, transcriptomics, pharmacological treatments, and knockout mice to elucidate the role of phagocytes and their modulation of the local inflammatory response through extracellular traps (ETs). Deciphering these mechanisms is essential for developing novel and enhanced immunotherapeutic approaches that can redirect a specific maladaptive immune response towards favorable wound healing in the retina. RESULTS Our findings underscore the pivotal role of innate immune cells, especially macrophages/monocytes, in regulating retinal repair and inflammation. The absence of neutrophil and macrophage infiltration aids parenchymal integrity restoration, while their depletion, particularly macrophages/monocytes, impedes vascular recovery. We demonstrate that macrophages/monocytes, when recruited in the retina, release chromatin and granular proteins, forming ETs. Furthermore, the pharmacological inhibition of ETosis support retinal and vascular repair, surpassing the effects of blocking innate immune cell recruitment. Simultaneously, the absence of ETosis reshapes the inflammatory response, causing neutrophils, helper, and cytotoxic T-cells to be restricted primarily in the superficial capillary plexus instead of reaching the damaged photoreceptor layer. CONCLUSIONS Our data offer novel insights into innate immunity's role in responding to retinal damage and potentially help developing innovative immunotherapeutic approaches that can shift the immune response from maladaptive to beneficial for retinal regeneration.
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Affiliation(s)
- Federica M Conedera
- Department of Oncology, Microbiology and Immunology, University of Fribourg, Fribourg, Switzerland.
- Department of Ophthalmology, Bern University Hospital and Department of BioMedical Research, University of Bern, Bern, Switzerland.
| | - Despina Kokona
- Department of Ophthalmology, Bern University Hospital and Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Martin S Zinkernagel
- Department of Ophthalmology, Bern University Hospital and Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Jens V Stein
- Department of Oncology, Microbiology and Immunology, University of Fribourg, Fribourg, Switzerland
| | - Charles P Lin
- Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Clemens Alt
- Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Volker Enzmann
- Department of Ophthalmology, Bern University Hospital and Department of BioMedical Research, University of Bern, Bern, Switzerland
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Wang J, Barwick SR, Xiao H, Smith SB. Evaluation of the role of Sigma 1 receptor and Cullin3 in retinal photoreceptor cells. Free Radic Biol Med 2023; 205:214-223. [PMID: 37328017 PMCID: PMC10527355 DOI: 10.1016/j.freeradbiomed.2023.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/24/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023]
Abstract
Sigma 1 receptor (Sig1R), a pluripotent modulator of cell survival, is neuroprotective in models of retinal degeneration when activated by the high-affinity, high-specificity ligand (+)-pentazocine ((+)-PTZ). The molecular mechanisms of Sig1R-mediated retinal neuroprotection are under investigation. We previously reported that the antioxidant regulatory transcription factor Nrf2 may be involved in Sig1R-mediated retinal photoreceptor cell (PRC) rescue. Cullin 3 (Cul3) is a component of the Nrf2-Keap1 antioxidant pathway and facilitates Nrf2 ubiquitination. Our earlier transcriptome analysis revealed decreased Cul3 in retinas lacking Sig1R. Here, we asked whether Sig1R activation can modulate Cul3 expression in 661 W cone PRCs. Proximity ligation and co-immunoprecipitation (co-IP) showed that Cul3 resides closely to and co-IPs with Sig1R. Activation of Sig1R using (+)-PTZ significantly increased Cul3 at the gene/protein level; silencing Sig1R decreased Cul3 gene/protein levels. Experiments in which Cul3 was silenced in cells exposed to tBHP resulted in increased oxidative stress, which was not attenuated with Sig1R activation by (+)-PTZ, whereas cells transfected with scrambled siRNA (and incubated with tBHP) responded to (+)-PTZ treatment by decreasing levels of oxidative stress. Assessment of mitochondrial respiration and glycolysis revealed significantly improved maximal respiration, spare capacity and glycolytic capacity in oxidatively-stressed cells transfected with scrambled siRNA and treated with (+)-PTZ, but not in (+)-PTZ treated, oxidatively-stressed cells in which Cul3 had been silenced. The data provide the first evidence that Sig1R co-localizes/interacts with Cul3, a key player in the Nrf2-Keap1 antioxidant pathway. The data suggest that the preservation of mitochondrial respiration/glycolytic function and reduction of oxidative stress observed upon activation of Sig1R occur in part in a Cul3-dependent manner.
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Affiliation(s)
- Jing Wang
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Shannon R Barwick
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Haiyan Xiao
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Sylvia B Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA; Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, GA, USA.
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Aredo B, Kumar A, Chen B, Xing C, Ufret-Vincenty RL. Single Cell RNA Sequencing Analysis of Mouse Retina Identifies a Subpopulation of Muller Glia Involved in Retinal Recovery From Injury in the FCD-LIRD Model. Invest Ophthalmol Vis Sci 2023; 64:2. [PMID: 37526616 PMCID: PMC10399600 DOI: 10.1167/iovs.64.11.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/09/2023] [Indexed: 08/02/2023] Open
Abstract
Purpose Although retinal light injury models have been useful in understanding aspects of retinal degeneration and retinal oxidative stress, information on retinal recovery from oxidative/photoinflammatory retinal injury is scarce. The fundus camera-delivered light-induced retinal degeneration model is a simple and reproducible retinal light injury model developed to recapitulate not only the retinal degeneration aspect, but also the retinal recovery from injury. In this study, we used the fundus camera-delivered light-induced retinal degeneration model to perform cell type-specific analyses of the acute and subacute retinal responses to light injury. Methods C57BL/6J eyes were collected before or after light injury (4 hours, 48 hours, and day 5). Retina samples were processed into single-cell suspensions. Droplet-based encapsulation of single cells was performed to generate libraries for sequencing. Results Gene expression analysis generated 23 clusters encompassing all known major retinal cell populations. Using unbiased analyses, we identified genes and pathways that were significantly altered in each cell type after light injury, including some cellular processes suggestive of activation of pathways for retinal recovery (e.g., synaptogenesis signaling, ephrin receptor signaling, and Reelin signaling in neurons). More importantly, our data show that a subpopulation of Muller glia cells may play an important role in the cellular recovery process. Conclusions This work identifies acute and subacute cell type-specific responses to retinal photo-oxidative injury. A subpopulation of Muller glia seems to initiate the cellular recovery process. A better understanding of these responses may be helpful in identifying therapeutic approaches to minimize retinal damage and maximize recovery after exposure to injury.
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Affiliation(s)
- Bogale Aredo
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Ashwani Kumar
- McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Bo Chen
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Chao Xing
- McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, Texas, United States
- Department of Bioinformatics, UT Southwestern Medical Center, Dallas, Texas, United States
- Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, Texas, United States
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Seitter H, Obkircher J, Grabher P, Hartl J, Zanetti L, Lux UT, Fotakis G, Fernández-Quintero ML, Kaserer T, Koschak A. A novel calcium channel Cavβ 2 splice variant with unique properties predominates in the retina. J Biol Chem 2023; 299:102972. [PMID: 36738788 PMCID: PMC10074810 DOI: 10.1016/j.jbc.2023.102972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Cavβ subunits are essential for surface expression of voltage-gated calcium channel complexes and crucially modulate biophysical properties like voltage-dependent inactivation. Here, we describe the discovery and characterization of a novel Cavβ2 variant with distinct features that predominates in the retina. We determined spliced exons in retinal transcripts of the Cacnb2 gene, coding for Cavβ2, by RNA-Seq data analysis and quantitative PCR. We cloned a novel Cavβ2 splice variant from mouse retina, which we are calling β2i, and investigated biophysical properties of calcium currents with this variant in a heterologous expression system as well as its intrinsic membrane interaction when expressed alone. Our data showed that β2i predominated in the retina with expression in photoreceptors and bipolar cells. Furthermore, we observed that the β2i N-terminus exhibited an extraordinary concentration of hydrophobic residues, a distinct feature not seen in canonical variants. The biophysical properties resembled known membrane-associated variants, and β2i exhibited both a strong membrane association and a propensity for clustering, which depended on hydrophobic residues in its N-terminus. We considered available Cavβ structure data to elucidate potential mechanisms underlying the observed characteristics but resolved N-terminus structures were lacking and thus, precluded clear conclusions. With this description of a novel N-terminus variant of Cavβ2, we expand the scope of functional variation through N-terminal splicing with a distinct form of membrane attachment. Further investigation of the molecular mechanisms underlying the features of β2i could provide new angles on the way Cavβ subunits modulate Ca2+ channels at the plasma membrane.
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Affiliation(s)
- Hartwig Seitter
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria.
| | - Jana Obkircher
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria
| | - Patricia Grabher
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria
| | - Julia Hartl
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria
| | - Lucia Zanetti
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria
| | - Uwe Thorsten Lux
- Department of Biology, Animal Physiology/Neurobiology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Georgios Fotakis
- Institute of Bioinformatics, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Teresa Kaserer
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria
| | - Alexandra Koschak
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria.
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Re-formation of synaptic connectivity in dissociated human stem cell-derived retinal organoid cultures. Proc Natl Acad Sci U S A 2023; 120:e2213418120. [PMID: 36598946 PMCID: PMC9926218 DOI: 10.1073/pnas.2213418120] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Human pluripotent stem cell (hPSC)-derived retinal organoids (ROs) can efficiently and reproducibly generate retinal neurons that have potential for use in cell replacement strategies [Capowski et al., Development 146, dev171686 (2019)]. The ability of these lab-grown retinal neurons to form new synaptic connections after dissociation from ROs is key to building confidence in their capacity to restore visual function. However, direct evidence of reestablishment of retinal neuron connectivity via synaptic tracing has not been reported to date. The present study employs an in vitro, rabies virus-based, monosynaptic retrograde tracing assay [Wickersham et al., Neuron 53, 639-647 (2007); Sun et al., Mol. Neurodegener. 14, 8 (2019)] to identify de novo synaptic connections among early retinal cell types following RO dissociation. A reproducible, high-throughput approach for labeling and quantifying traced retinal cell types was developed. Photoreceptors and retinal ganglion cells-the primary neurons of interest for retinal cell replacement-were the two major contributing populations among the traced presynaptic cells. This system provides a platform for assessing synaptic connections in cultured retinal neurons and sets the stage for future cell replacement studies aimed at characterizing or enhancing synaptogenesis. Used in this manner, in vitro synaptic tracing is envisioned to complement traditional preclinical animal model testing, which is limited by evolutionary incompatibilities in synaptic machinery inherent to human xenografts.
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Retinal Layer Separation (ReLayS) method enables the molecular analysis of photoreceptor segments and cell bodies, as well as the inner retina. Sci Rep 2022; 12:20195. [PMID: 36424523 PMCID: PMC9691741 DOI: 10.1038/s41598-022-24586-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 11/17/2022] [Indexed: 11/27/2022] Open
Abstract
Understanding the physiology of the retina, and especially of the highly polarized photoreceptors, is essential not only to broaden our knowledge of the processes required for normal vision, but also to develop effective therapies to prevent or slow retinal degenerative diseases. However, the molecular analysis of photoreceptors is a challenge due to the heterogeneity of the retinal tissue and the lack of easy and reliable methods for cell separation. Here we present the ReLayS method-a simple technique for the separation of photoreceptor segments (PS) containing both inner and outer segments, outer nuclear layer (ONL), and inner retina (InR) that contains the remaining retinal layers. The layer-specific material isolated from a mouse half-retina with the ReLayS method was sufficient for protein isolation and Western blotting or RNA isolation and real-time PCR studies. The separation of PS, ONL, and InR was successfully validated by Western blotting and real-time PCR using proteins and genes with known expression profiles within the retina. Furthermore, the separation of the PS from the ONL enabled the detection of light-driven translocation of transducin from the PS to the soma. ReLayS is a simple and useful method to address protein and possibly metabolites distribution in photoreceptor compartments in various situations including development, ageing, and degenerative diseases.
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Davison A, Lux UT, Brandstätter JH, Babai N. T-Type Ca 2+ Channels Boost Neurotransmission in Mammalian Cone Photoreceptors. J Neurosci 2022; 42:6325-6343. [PMID: 35803735 PMCID: PMC9398539 DOI: 10.1523/jneurosci.1878-21.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 06/13/2022] [Accepted: 06/22/2022] [Indexed: 11/21/2022] Open
Abstract
It is a commonly accepted view that light stimulation of mammalian photoreceptors causes a graded change in membrane potential instead of developing a spike. The presynaptic Ca2+ channels serve as a crucial link for the coding of membrane potential variations into neurotransmitter release. Cav1.4 L-type Ca2+ channels are expressed in photoreceptor terminals, but the complete pool of Ca2+ channels in cone photoreceptors appears to be more diverse. Here, we discovered, employing whole-cell patch-clamp recording from cone photoreceptor terminals in both sexes of mice, that their Ca2+ currents are composed of low- (T-type Ca2+ channels) and high- (L-type Ca2+ channels) voltage-activated components. Furthermore, Ca2+ channels exerted self-generated spike behavior in dark membrane potentials, and spikes were generated in response to light/dark transition. The application of fast and slow Ca2+ chelators revealed that T-type Ca2+ channels are located close to the release machinery. Furthermore, capacitance measurements indicated that they are involved in evoked vesicle release. Additionally, RT-PCR experiments showed the presence of Cav3.2 T-type Ca2+ channels in cone photoreceptors but not in rod photoreceptors. Altogether, we found several crucial functions of T-type Ca2+ channels, which increase the functional repertoire of cone photoreceptors. Namely, they extend cone photoreceptor light-responsive membrane potential range, amplify dark responses, generate spikes, increase intracellular Ca2+ levels, and boost synaptic transmission.SIGNIFICANCE STATEMENT Photoreceptors provide the first synapse for coding light information. The key elements in synaptic transmission are the voltage-sensitive Ca2+ channels. Here, we provide evidence that mouse cone photoreceptors express low-voltage-activated Cav3.2 T-type Ca2+ channels in addition to high-voltage-activated L-type Ca2+ channels. The presence of T-type Ca2+ channels in cone photoreceptors appears to extend their light-responsive membrane potential range, amplify dark response, generate spikes, increase intracellular Ca2+ levels, and boost synaptic transmission. By these functions, Cav3.2 T-type Ca2+ channels increase the functional repertoire of cone photoreceptors.
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Affiliation(s)
- Adam Davison
- Department of Biology, Animal Physiology/Neurobiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Uwe Thorsten Lux
- Department of Biology, Animal Physiology/Neurobiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Johann Helmut Brandstätter
- Department of Biology, Animal Physiology/Neurobiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Norbert Babai
- Department of Biology, Animal Physiology/Neurobiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
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Smith CL, Lan Y, Jain R, Epstein JA, Poleshko A. Global chromatin relabeling accompanies spatial inversion of chromatin in rod photoreceptors. SCIENCE ADVANCES 2021; 7:eabj3035. [PMID: 34559565 PMCID: PMC8462898 DOI: 10.1126/sciadv.abj3035] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
The nuclear architecture of rod photoreceptor cells in nocturnal mammals is unlike that of other animal cells. Murine rod cells have an “inverted” chromatin organization with euchromatin at the nuclear periphery and heterochromatin packed in the center of the nucleus. In conventional nuclear architecture, euchromatin is mostly in the interior, and heterochromatin is largely at the nuclear periphery. We demonstrate that inverted nuclear architecture is achieved through global relabeling of the rod cell epigenome. During rod cell maturation, H3K9me2-labeled nuclear peripheral heterochromatin is relabeled with H3K9me3 and repositioned to the nuclear center, while transcriptionally active euchromatin is labeled with H3K9me2 and positioned at the nuclear periphery. Global chromatin relabeling is correlated with spatial rearrangement, suggesting a critical role for histone modifications, specifically H3K9 methylation, in nuclear architecture. These results reveal a dramatic example of genome-wide epigenetic relabeling of chromatin that accompanies altered nuclear architecture in a postnatal, postmitotic cell.
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Affiliation(s)
- Cheryl L. Smith
- Department of Cell and Developmental Biology, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yemin Lan
- Department of Cell and Developmental Biology, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rajan Jain
- Department of Cell and Developmental Biology, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Medicine, Penn Cardiovascular Institute, and Institute of Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jonathan A. Epstein
- Department of Cell and Developmental Biology, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Medicine, Penn Cardiovascular Institute, and Institute of Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrey Poleshko
- Department of Cell and Developmental Biology, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Pavlou M, Schön C, Occelli LM, Rossi A, Meumann N, Boyd RF, Bartoe JT, Siedlecki J, Gerhardt MJ, Babutzka S, Bogedein J, Wagner JE, Priglinger SG, Biel M, Petersen‐Jones SM, Büning H, Michalakis S. Novel AAV capsids for intravitreal gene therapy of photoreceptor disorders. EMBO Mol Med 2021; 13:e13392. [PMID: 33616280 PMCID: PMC8033523 DOI: 10.15252/emmm.202013392] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 12/12/2022] Open
Abstract
Gene therapy using recombinant adeno-associated virus (rAAV) vectors to treat blinding retinal dystrophies has become clinical reality. Therapeutically impactful targeting of photoreceptors still relies on subretinal vector delivery, which detaches the retina and harbours substantial risks of collateral damage, often without achieving widespread photoreceptor transduction. Herein, we report the development of novel engineered rAAV vectors that enable efficient targeting of photoreceptors via less invasive intravitreal administration. A unique in vivo selection procedure was performed, where an AAV2-based peptide-display library was intravenously administered in mice, followed by isolation of vector DNA from target cells after only 24 h. This stringent selection yielded novel vectors, termed AAV2.GL and AAV2.NN, which mediate widespread and high-level retinal transduction after intravitreal injection in mice, dogs and non-human primates. Importantly, both vectors efficiently transduce photoreceptors in human retinal explant cultures. As proof-of-concept, intravitreal Cnga3 delivery using AAV2.GL lead to cone-specific expression of Cnga3 protein and rescued photopic cone responses in the Cnga3-/- mouse model of achromatopsia. These novel rAAV vectors expand the clinical applicability of gene therapy for blinding human retinal dystrophies.
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Affiliation(s)
- Marina Pavlou
- Department of OphthalmologyLudwig‐Maximilians‐UniversityMunichGermany
- Centre for Integrated Protein Science Munich (CIPSM) at the Department of PharmacyLudwig‐Maximilians‐UniversityMunichGermany
| | - Christian Schön
- Centre for Integrated Protein Science Munich (CIPSM) at the Department of PharmacyLudwig‐Maximilians‐UniversityMunichGermany
| | - Laurence M Occelli
- Department of Small Animal Clinical SciencesMichigan State UniversityEast LansingMIUSA
| | - Axel Rossi
- Laboratory for Infection Biology and Gene TransferInstitute of Experimental HaematologyHannover Medical SchoolHannoverGermany
| | - Nadja Meumann
- Laboratory for Infection Biology and Gene TransferInstitute of Experimental HaematologyHannover Medical SchoolHannoverGermany
- REBIRTH Research Centre for Translational Regenerative MedicineHannover Medical SchoolHannoverGermany
| | - Ryan F Boyd
- Ophthalmology ServicesCharles River LaboratoriesMattawanMIUSA
| | - Joshua T Bartoe
- Ophthalmology ServicesCharles River LaboratoriesMattawanMIUSA
| | - Jakob Siedlecki
- Department of OphthalmologyLudwig‐Maximilians‐UniversityMunichGermany
| | | | - Sabrina Babutzka
- Department of OphthalmologyLudwig‐Maximilians‐UniversityMunichGermany
- Centre for Integrated Protein Science Munich (CIPSM) at the Department of PharmacyLudwig‐Maximilians‐UniversityMunichGermany
| | - Jacqueline Bogedein
- Department of OphthalmologyLudwig‐Maximilians‐UniversityMunichGermany
- Centre for Integrated Protein Science Munich (CIPSM) at the Department of PharmacyLudwig‐Maximilians‐UniversityMunichGermany
| | - Johanna E Wagner
- Centre for Integrated Protein Science Munich (CIPSM) at the Department of PharmacyLudwig‐Maximilians‐UniversityMunichGermany
| | | | - Martin Biel
- Centre for Integrated Protein Science Munich (CIPSM) at the Department of PharmacyLudwig‐Maximilians‐UniversityMunichGermany
| | | | - Hildegard Büning
- Laboratory for Infection Biology and Gene TransferInstitute of Experimental HaematologyHannover Medical SchoolHannoverGermany
- REBIRTH Research Centre for Translational Regenerative MedicineHannover Medical SchoolHannoverGermany
| | - Stylianos Michalakis
- Department of OphthalmologyLudwig‐Maximilians‐UniversityMunichGermany
- Centre for Integrated Protein Science Munich (CIPSM) at the Department of PharmacyLudwig‐Maximilians‐UniversityMunichGermany
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12
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Murenu E, Pavlou M, Richter L, Rapti K, Just S, Cehajic-Kapetanovic J, Tafrishi N, Hayes A, Scholey R, Lucas R, Büning H, Grimm D, Michalakis S. A universal protocol for isolating retinal ON bipolar cells across species via fluorescence-activated cell sorting. Mol Ther Methods Clin Dev 2021; 20:587-600. [PMID: 33665228 PMCID: PMC7895692 DOI: 10.1016/j.omtm.2021.01.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/19/2021] [Indexed: 11/17/2022]
Abstract
Inherited retinal dystrophies (IRDs) are characterized by progressive degeneration and loss of light-sensing photoreceptors. The most promising therapeutic approach for IRDs is gene supplementation therapy using viral vectors, which requires the presence of viable photoreceptors at the time of intervention. At later disease stages, photoreceptors are lost and can no longer be rescued with this approach. For these patients, conferring light-sensing abilities to the remaining interneurons of the ON circuit (i.e., ON bipolar cells) using optogenetic tools poses an alternative treatment strategy. Such treatments, however, are hampered by the lack of efficient gene delivery tools targeting ON bipolar cells, which in turn rely on the effective isolation of these cells to facilitate tool development. Herein, we describe a method to selectively isolate ON bipolar cells via fluorescence-activated cell sorting (FACS), based on the expression of two intracellular markers. We show that the method is compatible with highly sensitive downstream analyses and suitable for the isolation of ON bipolar cells from healthy as well as degenerated mouse retinas. Moreover, we demonstrate that this approach works effectively using non-human primate (NHP) retinal tissue, thereby offering a reliable pipeline for universal screening strategies that do not require inter-species adaptations or transgenic animals.
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Affiliation(s)
- Elisa Murenu
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
- Department of Pharmacy, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Marina Pavlou
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
- Department of Pharmacy, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Lisa Richter
- Core Facility Flow Cytometry, Biomedical Center, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Kleopatra Rapti
- Department of Infectious Diseases/Virology, Medical Faculty, University of Heidelberg, 69120 Heidelberg, Germany
- BioQuant Center, University of Heidelberg, 69120 Heidelberg, Germany
| | - Sabrina Just
- Laboratory for Infection Biology and Gene Transfer, Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University and Oxford University Hospitals, Oxford OX3 9DU, UK
| | - Neda Tafrishi
- Core Facility Flow Cytometry, Gene Center, BioSysM, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Andrew Hayes
- Center for Biological Timing & School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Rachel Scholey
- Center for Biological Timing & School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Robert Lucas
- Center for Biological Timing & School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Hildegard Büning
- Laboratory for Infection Biology and Gene Transfer, Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, Hannover Medical School, 30625 Hannover, Germany
- German Center for Infection Research (DZIF), partner site, Hannover, Germany
| | - Dirk Grimm
- Department of Infectious Diseases/Virology, Medical Faculty, University of Heidelberg, 69120 Heidelberg, Germany
- BioQuant Center, University of Heidelberg, 69120 Heidelberg, Germany
- German Center for Infection Research (DZIF) and German Center for Cardiovascular Research (DZHK), partner site, Heidelberg, Germany
| | - Stylianos Michalakis
- Department of Ophthalmology, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
- Department of Pharmacy, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
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13
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Single-cell RNA sequencing in vision research: Insights into human retinal health and disease. Prog Retin Eye Res 2020; 83:100934. [PMID: 33383180 DOI: 10.1016/j.preteyeres.2020.100934] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/27/2020] [Accepted: 12/01/2020] [Indexed: 01/03/2023]
Abstract
Gene expression provides valuable insight into cell function. As such, vision researchers have frequently employed gene expression studies to better understand retinal physiology and disease. With the advent of single-cell RNA sequencing, expression experiments provide an unparalleled resolution of information. Instead of studying aggregated gene expression across all cells in a heterogenous tissue, single-cell technology maps RNA to an individual cell, which facilitates grouping of retinal and choroidal cell types for further study. Single-cell RNA sequencing has been quickly adopted by both basic and translational vision researchers, and single-cell level gene expression has been studied in the visual systems of animal models, retinal organoids, and primary human retina, RPE, and choroid. These experiments have generated detailed atlases of gene expression and identified new retinal cell types. Likewise, single-cell RNA sequencing investigations have characterized how gene expression changes in the setting of many retinal diseases, including how choroidal endothelial cells are altered in age-related macular degeneration. In addition, this technology has allowed vision researchers to discover drivers of retinal development and model rare retinal diseases with induced pluripotent stem cells. In this review, we will overview the growing number of single-cell RNA sequencing studies in the field of vision research. We will summarize experimental considerations for designing single-cell RNA sequencing experiments and highlight important advancements in retinal, RPE, choroidal, and retinal organoid biology driven by this technology. Finally, we generalize these findings to genes involved in retinal degeneration and outline the future of single-cell expression experiments in studying retinal disease.
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14
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Lerner S, Anderzhanova E, Verbitsky S, Eilam R, Kuperman Y, Tsoory M, Kuznetsov Y, Brandis A, Mehlman T, Mazkereth R, McCarter R, Segal M, Nagamani SCS, Chen A, Erez A. ASL Metabolically Regulates Tyrosine Hydroxylase in the Nucleus Locus Coeruleus. Cell Rep 2020; 29:2144-2153.e7. [PMID: 31747589 PMCID: PMC6902269 DOI: 10.1016/j.celrep.2019.10.043] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/18/2019] [Accepted: 10/10/2019] [Indexed: 12/14/2022] Open
Abstract
Patients with germline mutations in the urea-cycle enzyme argininosuccinate lyase (ASL) are at risk for developing neurobehavioral and cognitive deficits. We find that ASL is prominently expressed in the nucleus locus coeruleus (LC), the central source of norepinephrine. Using natural history data, we show that individuals with ASL deficiency are at risk for developing attention deficits. By generating LC-ASL-conditional knockout (cKO) mice, we further demonstrate altered response to stressful stimuli with increased seizure reactivity in LC-ASL-cKO mice. Depletion of ASL in LC neurons leads to reduced amount and activity of tyrosine hydroxylase (TH) and to decreased catecholamines synthesis, due to decreased nitric oxide (NO) signaling. NO donors normalize catecholamine levels in the LC, seizure sensitivity, and the stress response in LC-ASL-cKO mice. Our data emphasize ASL importance for the metabolic regulation of LC function with translational relevance for ASL deficiency (ASLD) patients as well as for LC-related pathologies. ASL is expressed in the locus coeruleus (LC) and regulates catecholamine synthesis LC-ASL deficiency in mice promotes abnormal stress response and seizure sensitivity LC-ASL deficiency decreases nitric-oxide levels and tyrosine hydroxylase activity NO donors normalize catecholamine production and rescue LC-ASL deficiency phenotype
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Affiliation(s)
- Shaul Lerner
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Elmira Anderzhanova
- Department of Stress Neurobiology and Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany; Clinic for Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | - Sima Verbitsky
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel; Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Raya Eilam
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Yael Kuperman
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Michael Tsoory
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Yuri Kuznetsov
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Alexander Brandis
- Life Science Core Facility, Weizmann Institute of Science, Rehovot, Israel
| | - Tevie Mehlman
- Life Science Core Facility, Weizmann Institute of Science, Rehovot, Israel
| | - Ram Mazkereth
- The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Robert McCarter
- Center for Translational Sciences, Children's National Health System, The George Washington University, Washington, DC, USA
| | - Menahem Segal
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Sandesh C S Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Alon Chen
- Department of Stress Neurobiology and Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany; Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Ayelet Erez
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
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15
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Forward genetic analysis using OCT screening identifies Sfxn3 mutations leading to progressive outer retinal degeneration in mice. Proc Natl Acad Sci U S A 2020; 117:12931-12942. [PMID: 32457148 DOI: 10.1073/pnas.1921224117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Retinal disease and loss of vision can result from any disruption of the complex pathways controlling retinal development and homeostasis. Forward genetics provides an excellent tool to find, in an unbiased manner, genes that are essential to these processes. Using N-ethyl-N-nitrosourea mutagenesis in mice in combination with a screening protocol using optical coherence tomography (OCT) and automated meiotic mapping, we identified 11 mutations presumably causative of retinal phenotypes in genes previously known to be essential for retinal integrity. In addition, we found multiple statistically significant gene-phenotype associations that have not been reported previously and decided to target one of these genes, Sfxn3 (encoding sideroflexin-3), using CRISPR/Cas9 technology. We demonstrate, using OCT, light microscopy, and electroretinography, that two Sfxn3 -/- mouse lines developed progressive and severe outer retinal degeneration. Electron microscopy showed thinning of the retinal pigment epithelium and disruption of the external limiting membrane. Using single-cell RNA sequencing of retinal cells isolated from C57BL/6J mice, we demonstrate that Sfxn3 is expressed in several bipolar cell subtypes, retinal ganglion cells, and some amacrine cell subtypes but not significantly in Müller cells or photoreceptors. In situ hybridization confirmed these findings. Furthermore, pathway analysis suggests that Sfxn3 may be associated with synaptic homeostasis. Importantly, electron microscopy analysis showed disruption of synapses and synaptic ribbons in the outer plexiform layer of Sfxn3 -/- mice. Our work describes a previously unknown requirement for Sfxn3 in retinal function.
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16
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Voigt AP, Binkley E, Flamme-Wiese MJ, Zeng S, DeLuca AP, Scheetz TE, Tucker BA, Mullins RF, Stone EM. Single-Cell RNA Sequencing in Human Retinal Degeneration Reveals Distinct Glial Cell Populations. Cells 2020; 9:cells9020438. [PMID: 32069977 PMCID: PMC7072666 DOI: 10.3390/cells9020438] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/07/2020] [Accepted: 02/07/2020] [Indexed: 12/15/2022] Open
Abstract
Degenerative diseases affecting retinal photoreceptor cells have numerous etiologies and clinical presentations. We clinically and molecularly studied the retina of a 70-year-old patient with retinal degeneration attributed to autoimmune retinopathy. The patient was followed for 19 years for progressive peripheral visual field loss and pigmentary changes. Single-cell RNA sequencing was performed on foveal and peripheral retina from this patient and four control patients, and cell-specific gene expression differences were identified between healthy and degenerating retina. Distinct populations of glial cells, including astrocytes and Müller cells, were identified in the tissue from the retinal degeneration patient. The glial cell populations demonstrated an expression profile consistent with reactive gliosis. This report provides evidence that glial cells have a distinct transcriptome in the setting of human retinal degeneration and represents a complementary clinical and molecular investigation of a case of progressive retinal disease.
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Affiliation(s)
- Andrew P. Voigt
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA
| | - Elaine Binkley
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA
| | - Miles J. Flamme-Wiese
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA
| | - Shemin Zeng
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA
| | - Adam P. DeLuca
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA
| | - Todd E. Scheetz
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA
| | - Budd A. Tucker
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA
| | - Robert F. Mullins
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA
| | - Edwin M. Stone
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
- Institute for Vision Research, The University of Iowa, Iowa City, IA 52242, USA
- Correspondence:
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17
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Subramanian K, Weigert M, Borsch O, Petzold H, Garcia-Ulloa A, Myers EW, Ader M, Solovei I, Kreysing M. Rod nuclear architecture determines contrast transmission of the retina and behavioral sensitivity in mice. eLife 2019; 8:49542. [PMID: 31825309 PMCID: PMC6974353 DOI: 10.7554/elife.49542] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 12/11/2019] [Indexed: 01/06/2023] Open
Abstract
Rod photoreceptors of nocturnal mammals display a striking inversion of nuclear architecture, which has been proposed as an evolutionary adaptation to dark environments. However, the nature of visual benefits and the underlying mechanisms remains unclear. It is widely assumed that improvements in nocturnal vision would depend on maximization of photon capture at the expense of image detail. Here, we show that retinal optical quality improves 2-fold during terminal development, and that this enhancement is caused by nuclear inversion. We further demonstrate that improved retinal contrast transmission, rather than photon-budget or resolution, enhances scotopic contrast sensitivity by 18–27%, and improves motion detection capabilities up to 10-fold in dim environments. Our findings therefore add functional significance to a prominent exception of nuclear organization and establish retinal contrast transmission as a decisive determinant of mammalian visual perception.
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Affiliation(s)
- Kaushikaram Subramanian
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany.,Cluster of Excellence, Physics of Life, Technische Universität Dresden, Dresden, Germany
| | - Martin Weigert
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany.,Cluster of Excellence, Physics of Life, Technische Universität Dresden, Dresden, Germany
| | - Oliver Borsch
- Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Heike Petzold
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | | - Eugene W Myers
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany.,Cluster of Excellence, Physics of Life, Technische Universität Dresden, Dresden, Germany.,Department of Computer Science, Technische Universität Dresden, Dresden, Germany
| | - Marius Ader
- Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Irina Solovei
- Biozentrum, Ludwig Maximilians Universität, München, Germany
| | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany.,Cluster of Excellence, Physics of Life, Technische Universität Dresden, Dresden, Germany
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18
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Heterochromatin drives compartmentalization of inverted and conventional nuclei. Nature 2019; 570:395-399. [PMID: 31168090 DOI: 10.1038/s41586-019-1275-3] [Citation(s) in RCA: 345] [Impact Index Per Article: 69.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/26/2019] [Indexed: 01/18/2023]
Abstract
The nucleus of mammalian cells displays a distinct spatial segregation of active euchromatic and inactive heterochromatic regions of the genome1,2. In conventional nuclei, microscopy shows that euchromatin is localized in the nuclear interior and heterochromatin at the nuclear periphery1,2. Genome-wide chromosome conformation capture (Hi-C) analyses show this segregation as a plaid pattern of contact enrichment within euchromatin and heterochromatin compartments3, and depletion between them. Many mechanisms for the formation of compartments have been proposed, such as attraction of heterochromatin to the nuclear lamina2,4, preferential attraction of similar chromatin to each other1,4-12, higher levels of chromatin mobility in active chromatin13-15 and transcription-related clustering of euchromatin16,17. However, these hypotheses have remained inconclusive, owing to the difficulty of disentangling intra-chromatin and chromatin-lamina interactions in conventional nuclei18. The marked reorganization of interphase chromosomes in the inverted nuclei of rods in nocturnal mammals19,20 provides an opportunity to elucidate the mechanisms that underlie spatial compartmentalization. Here we combine Hi-C analysis of inverted rod nuclei with microscopy and polymer simulations. We find that attractions between heterochromatic regions are crucial for establishing both compartmentalization and the concentric shells of pericentromeric heterochromatin, facultative heterochromatin and euchromatin in the inverted nucleus. When interactions between heterochromatin and the lamina are added, the same model recreates the conventional nuclear organization. In addition, our models allow us to rule out mechanisms of compartmentalization that involve strong euchromatin interactions. Together, our experiments and modelling suggest that attractions between heterochromatic regions are essential for the phase separation of the active and inactive genome in inverted and conventional nuclei, whereas interactions of the chromatin with the lamina are necessary to build the conventional architecture from these segregated phases.
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19
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Maeder ML, Stefanidakis M, Wilson CJ, Baral R, Barrera LA, Bounoutas GS, Bumcrot D, Chao H, Ciulla DM, DaSilva JA, Dass A, Dhanapal V, Fennell TJ, Friedland AE, Giannoukos G, Gloskowski SW, Glucksmann A, Gotta GM, Jayaram H, Haskett SJ, Hopkins B, Horng JE, Joshi S, Marco E, Mepani R, Reyon D, Ta T, Tabbaa DG, Samuelsson SJ, Shen S, Skor MN, Stetkiewicz P, Wang T, Yudkoff C, Myer VE, Albright CF, Jiang H. Development of a gene-editing approach to restore vision loss in Leber congenital amaurosis type 10. Nat Med 2019; 25:229-233. [DOI: 10.1038/s41591-018-0327-9] [Citation(s) in RCA: 338] [Impact Index Per Article: 67.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 12/07/2018] [Indexed: 12/18/2022]
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20
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Sun C, Mitchell DM, Stenkamp DL. Isolation of photoreceptors from mature, developing, and regenerated zebrafish retinas, and of microglia/macrophages from regenerating zebrafish retinas. Exp Eye Res 2018; 177:130-144. [PMID: 30096325 DOI: 10.1016/j.exer.2018.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/30/2018] [Accepted: 08/06/2018] [Indexed: 12/16/2022]
Abstract
This paper describes experimental procedures for the dissociation of retinal cells of the zebrafish (Danio rerio) for subsequent fluorescence-activated cell sorting (FACS) and gene expression studies. Methods for dissociation of zebrafish retinas followed by FACS and RNA isolation were optimized. This methodology was applied to isolate pure sorted samples of rods, long wavelength-sensitive (LWS) cones, medium wavelength-sensitive (MWS; RH2-2) cones, short wavelength-sensitive (SWS2) cones, and UV-sensitive (SWS1) cones from retinas obtained at selective life-history stages of the zebrafish, and for some of these photoreceptors, following retinal regeneration. We also successfully separated lws1-expressing and lws2-expressing LWS cones from fish of a transgenic line in which lws1 is reported with green fluorescence protein (GFP) and lws2 is reported with red fluorescence protein (RFP). Microglia/macrophages were successfully sorted from regenerating retinas (7 days after a cytotoxic lesion) of a transgenic line in which these immune cells express GFP. Electropherograms verified downstream isolation of high-quality RNA from sorted samples. Examples of post-sorting analysis, as well as results of qRT-PCR studies, validated the purity of sorted populations. For example, qRT-PCR samples derived from isolated Rh2-2 cones contained detectable rh2-2 (opn1mw2) opsin transcripts, but lws opsin transcripts (lws1/opn1lw1, lws2/opn1lw2) were not detected, suggesting that the procedure likely separated double cone pairs. Through this method, pure, sorted cell samples can provide RNA that is reliable for downstream gene expression analyses, such as qRT-PCR and RNA-seq, which may reveal molecular signatures of photoreceptors and microglia for comparative transcriptomics studies.
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Affiliation(s)
- Chi Sun
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844, USA
| | - Diana M Mitchell
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844, USA
| | - Deborah L Stenkamp
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844, USA.
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21
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Ban N, Lee TJ, Sene A, Dong Z, Santeford A, Lin JB, Ory DS, Apte RS. Disrupted cholesterol metabolism promotes age-related photoreceptor neurodegeneration. J Lipid Res 2018; 59:1414-1423. [PMID: 29946056 PMCID: PMC6071770 DOI: 10.1194/jlr.m084442] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/12/2018] [Indexed: 12/17/2022] Open
Abstract
Photoreceptors have high intrinsic metabolic demand and are exquisitely sensitive to metabolic perturbation. In addition, they shed a large portion of their outer segment lipid membranes in a circadian manner, increasing the metabolic burden on the outer retina associated with the resynthesis of cell membranes and disposal of the cellular cargo. Here, we demonstrate that deletion of both ABCA1 and ABCG1 in rod photoreceptors leads to age-related accumulation of cholesterol metabolites in the outer retina, photoreceptor dysfunction, degeneration of rod outer segments, and ultimately blindness. A high-fat diet significantly accelerates rod neurodegeneration and vision loss, further highlighting the role of lipid homeostasis in regulating photoreceptor neurodegeneration and vision.
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Affiliation(s)
- Norimitsu Ban
- Departments of Ophthalmology and Visual Sciences Washington University School of Medicine in St. Louis, St. Louis, MO 63110
| | - Tae Jun Lee
- Departments of Ophthalmology and Visual Sciences Washington University School of Medicine in St. Louis, St. Louis, MO 63110
| | - Abdoulaye Sene
- Departments of Ophthalmology and Visual Sciences Washington University School of Medicine in St. Louis, St. Louis, MO 63110
| | - Zhenyu Dong
- Departments of Ophthalmology and Visual Sciences Washington University School of Medicine in St. Louis, St. Louis, MO 63110
| | - Andrea Santeford
- Departments of Ophthalmology and Visual Sciences Washington University School of Medicine in St. Louis, St. Louis, MO 63110
| | - Jonathan B Lin
- Departments of Ophthalmology and Visual Sciences Washington University School of Medicine in St. Louis, St. Louis, MO 63110
- Neuroscience Graduate Program, Division of Biology and Biomedical Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO 63110
| | - Daniel S Ory
- Diabetic Cardiovascular Disease Center, Washington University School of Medicine in St. Louis, St. Louis, MO 63110
| | - Rajendra S Apte
- Departments of Ophthalmology and Visual Sciences Washington University School of Medicine in St. Louis, St. Louis, MO 63110
- Neuroscience Graduate Program, Division of Biology and Biomedical Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO 63110
- Medicine and Developmental Biology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110
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22
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Inamdar SM, Lankford CK, Laird JG, Novbatova G, Tatro N, Whitmore SS, Scheetz TE, Baker SA. Analysis of 14-3-3 isoforms expressed in photoreceptors. Exp Eye Res 2018; 170:108-116. [PMID: 29486162 DOI: 10.1016/j.exer.2018.02.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/02/2018] [Accepted: 02/23/2018] [Indexed: 11/18/2022]
Abstract
The 14-3-3 family of proteins has undergone considerable expansion in higher eukaryotes with humans and mice expressing seven isoforms (β, ε, η, γ, θ, ζ, and σ) from seven distinct genes (YWHAB, YWAHE, YWHAH, YWHAG, YWHAQ, YWHAZ, and SFN). Growing evidence indicates that while highly conserved, these isoforms are not entirely functionally redundant as they exhibit unique tissue expression profiles, subcellular localization, and biochemical functions. A key limitation in our understanding of 14-3-3 biology lies in our limited knowledge of cell-type specific 14-3-3 expression. Here we provide a characterization of 14-3-3 expression in whole retina and isolated rod photoreceptors using reverse-transcriptase digital droplet PCR. We find that all 14-3-3 genes with the exception of SFN are expressed in mouse retina with YWHAQ and YWHAE being the most highly expressed. Rod photoreceptors are enriched in YWHAE (14-3-3 ε). Immunohistochemistry revealed that 14-3-3 ε and 14-3-3 ζ exhibit unique distributions in photoreceptors with 14-3-3 ε restricted to the inner segment and 14-3-3 ζ localized to the outer segment. Our data demonstrates that, in the retina, 14-3-3 isoforms likely serve specific functions as they exhibit unique expression levels and cell-type specificity. As such, future investigations into 14-3-3 function in rod photoreceptors should be centered on 14-3-3 ε and 14-3-3 ζ, depending on the subcellular region of question.
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Affiliation(s)
- Shivangi M Inamdar
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Colten K Lankford
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Joseph G Laird
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Gulnara Novbatova
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Nicole Tatro
- Department of Ophthalmology & Visual Sciences and Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - S Scott Whitmore
- Department of Ophthalmology & Visual Sciences and Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Todd E Scheetz
- Department of Ophthalmology & Visual Sciences and Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Sheila A Baker
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA; Department of Ophthalmology & Visual Sciences and Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA.
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23
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Hung SS, Li F, Wang JH, King AE, Bui BV, Liu GS, Hewitt AW. Methods for In Vivo CRISPR/Cas Editing of the Adult Murine Retina. Methods Mol Biol 2018; 1715:113-133. [PMID: 29188510 DOI: 10.1007/978-1-4939-7522-8_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein (Cas) is used by some bacteria and most archaea to protect against viral phage intrusion and has recently been adapted to allow for efficient editing of the mammalian genome. Whilst CRISPR/Cas-based technology has been used to modify genes in mammalian cells in vitro, delivery of CRISPR/Cas system into mammalian tissue and/or organs is more difficult and often requires additional vectors. With the use of adeno-associated virus (AAV) gene delivery system, active CRISPR/Cas enzyme can be maintained for an extended period of time and enable efficient editing of genome in the retina in vivo. Herein we outline the method to edit the genome in mouse retina using a dual AAV vector -mediated CRISPR/Cas9 system.
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Affiliation(s)
- Sandy S Hung
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
| | - Fan Li
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Menzies Institute for Medical Research, School of Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Jiang-Hui Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Anna E King
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS, Australia
| | - Bang V Bui
- Department of Optometry & Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Guei-Sheung Liu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia.
- Menzies Institute for Medical Research, School of Medicine, University of Tasmania, Hobart, TAS, Australia.
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia.
| | - Alex W Hewitt
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia.
- Menzies Institute for Medical Research, School of Medicine, University of Tasmania, Hobart, TAS, Australia.
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia.
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24
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Glaviano A, Smith AJ, Blanco A, McLoughlin S, Cederlund ML, Heffernan T, Sapetto-Rebow B, Alvarez Y, Yin J, Kennedy BN. A method for isolation of cone photoreceptors from adult zebrafish retinae. BMC Neurosci 2016; 17:71. [PMID: 27821066 PMCID: PMC5100264 DOI: 10.1186/s12868-016-0307-2] [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] [Received: 06/22/2016] [Accepted: 10/31/2016] [Indexed: 11/08/2022] Open
Abstract
Background Cone photoreceptors are specialised sensory retinal neurons responsible for photopic vision, colour perception and visual acuity. Retinal degenerative diseases are a heterogeneous group of eye diseases in which the most severe vision loss typically arises from cone photoreceptor dysfunction or degeneration. Establishing a method to purify cone photoreceptors from retinal tissue can accelerate the identification of key molecular determinants that underlie cone photoreceptor development, survival and function. The work herein describes a new method to purify enhanced green fluorescent protein (EGFP)-labelled cone photoreceptors from adult retina of Tg(3.2gnat2:EGFP) zebrafish. Results Methods for dissecting adult zebrafish retinae, cell dissociation, cell sorting, RNA isolation and RNA quality control were optimised. The dissociation protocol, carried out with ~30 retinae from adult zebrafish, yielded approximately 6 × 106 cells. Flow cytometry cell sorting subsequently distinguished 1 × 106 EGFP+ cells and 4 × 106 EGFP− cells. Electropherograms confirmed downstream isolation of high-quality RNA with RNA integrity number (RIN) >7.6 and RNA concentration >5.7 ng/µl obtained from both populations. Reverse Transcriptase-PCR confirmed that the EGFP-positive cell populations express known genetic markers of cone photoreceptors that were not expressed in the EGFP-negative cell population whereas a rod opsin amplicon was only detected in the EGFP-negative retinal cell population. Conclusions This work describes a valuable adult zebrafish cone photoreceptor isolation methodology enabling future identification of cone photoreceptor-enriched genes, proteins and signalling networks responsible for their development, survival and function. In addition, this advancement facilitates the identification of novel candidate genes for inherited human blindness.
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Affiliation(s)
- Antonino Glaviano
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Andrew J Smith
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Alfonso Blanco
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Sarah McLoughlin
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Maria L Cederlund
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Theresa Heffernan
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Beata Sapetto-Rebow
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Yolanda Alvarez
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Jun Yin
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Breandán N Kennedy
- UCD School of Biomolecular & Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, D04 V1W8, Ireland.
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25
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Cho SH, Song JY, Shin J, Kim S. Neonatal disease environment limits the efficacy of retinal transplantation in the LCA8 mouse model. BMC Ophthalmol 2016; 16:193. [PMID: 27809828 PMCID: PMC5095973 DOI: 10.1186/s12886-016-0368-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/20/2016] [Indexed: 11/17/2022] Open
Abstract
Background Mutations of Crb1 gene cause irreversible and incurable visual impairment in humans. This study aims to use an LCA8-like mouse model to identify host-mediated responses that might interfere with survival, retinal integration and differentiation of grafted cells during neonatal cell therapy. Methods Mixed retinal donor cells (1 ~ 2 × 104) isolated from neural retinas of neonatal eGFP transgenic mice were injected into the subretinal space of LCA8-like model neonatal mice. Markers of specific cell types were used to analyze microglial attraction, CSPG induction and retinal cell differentiation. The positions of host retinal cells were traced according to their laminar location during disease progression to look for host cell rearrangements that might inhibit retinal integration of the transplanted cells. Results Transplanted retinal cells showed poor survival and attracted microglial cells, but CSPG was not greatly induced. Retinas of the LCA8 model hosts underwent significant cellular rearrangement, including rosette formation and apical displacement of inner retinal cells. Conclusions Local disease environment, particularly host immune responses to injected cells and formation of a physical barrier caused by apical migration of host retinal cells upon disruption of outer limiting membrane, may impose two major barriers in LCAs cell transplantation therapy.
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Affiliation(s)
- Seo-Hee Cho
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA, 19140, USA.
| | - Ji Yun Song
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA, 19140, USA
| | - Jinyeon Shin
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA, 19140, USA
| | - Seonhee Kim
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA, 19140, USA
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26
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Murphy D, Cieply B, Carstens R, Ramamurthy V, Stoilov P. The Musashi 1 Controls the Splicing of Photoreceptor-Specific Exons in the Vertebrate Retina. PLoS Genet 2016; 12:e1006256. [PMID: 27541351 PMCID: PMC4991804 DOI: 10.1371/journal.pgen.1006256] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/22/2016] [Indexed: 01/08/2023] Open
Abstract
Alternative pre-mRNA splicing expands the coding capacity of eukaryotic genomes, potentially enabling a limited number of genes to govern the development of complex anatomical structures. Alternative splicing is particularly prevalent in the vertebrate nervous system, where it is required for neuronal development and function. Here, we show that photoreceptor cells, a type of sensory neuron, express a characteristic splicing program that affects a broad set of transcripts and is initiated prior to the development of the light sensing outer segments. Surprisingly, photoreceptors lack prototypical neuronal splicing factors and their splicing profile is driven to a significant degree by the Musashi 1 (MSI1) protein. A striking feature of the photoreceptor splicing program are exons that display a "switch-like" pattern of high inclusion levels in photoreceptors and near complete exclusion outside of the retina. Several ubiquitously expressed genes that are involved in the biogenesis and function of primary cilia produce highly photoreceptor specific isoforms through use of such "switch-like" exons. Our results suggest a potential role for alternative splicing in the development of photoreceptors and the conversion of their primary cilia to the light sensing outer segments.
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Affiliation(s)
- Daniel Murphy
- Department of Biochemistry, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia, United States of America
| | - Benjamin Cieply
- Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Russ Carstens
- Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Visvanathan Ramamurthy
- Departments of Biochemistry, Ophthalmology and Center for Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia, United States of America
| | - Peter Stoilov
- Department of Biochemistry and Cancer Institute, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia, United States of America
- * E-mail:
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27
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Jimeno D, Santos E. A new functional role uncovered for RASGRF2 in control of nuclear migration in cone photoreceptors during postnatal retinal development. Small GTPases 2016; 8:26-30. [PMID: 27221061 DOI: 10.1080/21541248.2016.1189989] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Despite their homologous structure and central nervous system(CNS) expression patterns, the GRF1 and GRF2 guanine nucleotide exchange factors(GEF) appear to play distinct, non-overlapping functions in cellular excitability, synaptic plasticity or neuromodulation. We recently uncovered a new functional role of GRF2 controlling nuclear migration in cone photoreceptors during postnatal neuroepithelial differentiation of the mouse retina. Analyzing GRF2-KO mice, we detected the specific accumulation of abnormally located, "ectopic" cone photoreceptor nuclei in the photoreceptor segment(PS) layer of their retinas. This alteration was accompanied by defective electroretinograms(ERG) indicative of impaired cone-mediated visual function, and accumulation around the "ectopic" nuclei of signaling molecules known to be functionally relevant for intracellular organelle migration, cytoskeletal reorganization or cell polarity establishment including PAR3, PAR6, and the phosphorylated proteins pPAK, pMLC2 and pVASP. We propose a mechanism whereby the absence of a productive functional interaction between GRF2 and its downstream target CDC42 leads to altered formation/structure of PAR-containing, polarity-related macromolecular complexes and abnormal activation of downstream signaling mediated by activated, phosphorylated forms of PAK, VASP and MLC2. As cone photoreceptors are responsible for color vision and visual acuity, these observations are potentially relevant for degenerative diseases of the human retina, harboring almost double number of cones than mice.
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Affiliation(s)
- David Jimeno
- a Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC- Universidad de Salamanca) , Salamanca , Spain
| | - Eugenio Santos
- a Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC- Universidad de Salamanca) , Salamanca , Spain
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28
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Laird JG, Pan Y, Modestou M, Yamaguchi DM, Song H, Sokolov M, Baker SA. Identification of a VxP Targeting Signal in the Flagellar Na+ /K+ -ATPase. Traffic 2015; 16:1239-53. [PMID: 26373354 DOI: 10.1111/tra.12332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 09/11/2015] [Accepted: 09/11/2015] [Indexed: 12/15/2022]
Abstract
Na(+) /K(+) -ATPase (NKA) participates in setting electrochemical gradients, cardiotonic steroid signaling and cellular adhesion. Distinct isoforms of NKA are found in different tissues and subcellular localization patterns. For example, NKA α1 is widely expressed, NKA α3 is enriched in neurons and NKA α4 is a testes-specific isoform found in sperm flagella. In some tissues, ankyrin, a key component of the membrane cytoskeleton, can regulate the trafficking of NKA. In the retina, NKA and ankyrin-B are expressed in multiple cell types and immunostaining for each is striking in the synaptic layers. Labeling for NKA is also prominent along the inner segment plasma membrane (ISPM) of photoreceptors. NKA co-immunoprecipitates with ankyrin-B, but on a subcellular level colocalization of these two proteins varies dependent on the cell type. We used transgenic Xenopus laevis tadpoles to evaluate the subcellular trafficking of NKA in photoreceptors. GFP-NKA α3 and α1 are localized to the ISPM, but α4 is localized to outer segments (OSs). We identified a VxP motif responsible for the OS targeting by using a series of chimeric and mutant NKA constructs. This motif is similar to previously identified ciliary targeting motifs. Given the structural similarities between OSs and flagella, our findings shed light on the subcellular targeting of this testes-specific NKA isoform.
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Affiliation(s)
- Joseph G Laird
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Yuan Pan
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.,Current address: Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Modestos Modestou
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - David M Yamaguchi
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Hongman Song
- Department of Ophthalmology, West Virginia University School of Medicine and West Virginia University Eye Institute, Morgantown, WV, 26506, USA.,Current address: Section for Translational Research in Retina & Macular Degeneration, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, 20892, USA
| | - Maxim Sokolov
- Department of Ophthalmology, West Virginia University School of Medicine and West Virginia University Eye Institute, Morgantown, WV, 26506, USA
| | - Sheila A Baker
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
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