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Sripinun P, See LP, Nikonov S, Chavali VRM, Vrathasha V, He J, O'Brien JM, Xia J, Lu W, Mitchell CH. Piezo1 and Piezo2 channels in retinal ganglion cells and the impact of Piezo1 stimulation on light-dependent neural activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.599602. [PMID: 38979351 PMCID: PMC11230181 DOI: 10.1101/2024.06.25.599602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Piezo channels are associated with neuropathology in diseases like traumatic brain injury and glaucoma, but pathways linking tissue stretch to aberrant neural signaling remain unclear. The present study demonstrates that Piezo1 activation increases action potential frequency in response to light and the spontaneous dark signal from mouse retinal explants. Piezo1 stimulation was sufficient to increase cytoplasmic Ca 2+ in soma and neurites, while stretch increased spiking activity in current clamp recordings from of isolated retinal ganglion cells (RGCs). Axon-marker beta-tubulin III colocalized with both Piezo1 and Piezo2 protein in the mouse optic nerve head, while RGC nuclear marker BRN3A colocalized with Piezo channels in the soma. Piezo1 was also present on GFAP-positive regions in the optic nerve head and colocalized with glutamine synthetase in the nerve fiber layer, suggesting expression in optic nerve head astrocytes and Müller glia end feet, respectively. Human RGCs from induced pluripotent stem cells also expressed Piezo1 and Piezo2 in soma and axons, while staining patterns in rats resembled those in mice. mRNA message for Piezo1 was greatest in the RPE/choroid tissue, while Piezo2 levels were highest in the optic nerve, with both channels also expressed in the retina. Increased expression of Piezo1 and Piezo2 occurred both 1 and 10 days after a single stretch in vivo; this increase suggests a potential role in rising sensitivity to repeated nerve stretch. In summary, Piezo1 and Piezo2 were detected in the soma and axons of RGCs, and stimulation affected the light-dependent output of RGCs. The rise in RGCs excitability induced by Piezo stimulation may have parallels to the early disease progression in models of glaucoma and other retinal degenerations. Highlights Activation of Piezo1 excites retinal ganglion cells, paralleling the early neurodegenerative progression in glaucoma mouse models and retinal degeneration.Piezo1 and Piezo2 were expressed in axons and soma of retinal ganglion cells in mice, rats, and human iPSC-RGCs.Functional assays confirmed Piezo1 in soma and neurites of neurons. Sustained elevation of Piezo1 and Piezo2 occurred after a single transient stretch may enhance damage from repeated traumatic nerve injury. Abstract Figure
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Yee T, Wert KJ. Human retina-in-a-dish: Unlocking the potential to study mechanisms of inherited retinal disease. Mol Ther Methods Clin Dev 2023; 30:573-575. [PMID: 37693947 PMCID: PMC10485576 DOI: 10.1016/j.omtm.2023.08.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Affiliation(s)
- Tiffany Yee
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Katherine J. Wert
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX 75390, USA
- Peter O’Donnell Jr. Brain Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
- Hamon Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA
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Lawrence ECN, Guo M, Schwartz TD, Wu J, Lu J, Nikonov S, Sterling JK, Cui QN. Topical and systemic GLP-1R agonist administration both rescue retinal ganglion cells in hypertensive glaucoma. Front Cell Neurosci 2023; 17:1156829. [PMID: 37362000 PMCID: PMC10288152 DOI: 10.3389/fncel.2023.1156829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/05/2023] [Indexed: 06/28/2023] Open
Abstract
Glaucomatous neurodegeneration, a blinding disease affecting millions worldwide, has a need for the exploration of new and effective therapies. Previously, the glucagon-like peptide-1 receptor (GLP-1R) agonist NLY01 was shown to reduce microglia/macrophage activation, rescuing retinal ganglion cells after IOP elevation in an animal model of glaucoma. GLP-1R agonist use is also associated with a reduced risk for glaucoma in patients with diabetes. In this study, we demonstrate that several commercially available GLP-1R agonists, administered either systemically or topically, hold protective potential in a mouse model of hypertensive glaucoma. Further, the resulting neuroprotection likely occurs through the same pathways previously shown for NLY01. This work contributes to a growing body of evidence suggesting that GLP-1R agonists represent a viable therapeutic option for glaucoma.
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Affiliation(s)
| | | | | | | | | | | | | | - Qi N. Cui
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
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4
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Afanasyeva TA, Athanasiou D, Perdigao PR, Whiting KR, Duijkers L, Astuti GD, Bennett J, Garanto A, van der Spuy J, Roepman R, Cheetham ME, Collin RW. CRISPR-Cas9 correction of a nonsense mutation in LCA5 rescues lebercilin expression and localization in human retinal organoids. Mol Ther Methods Clin Dev 2023; 29:522-531. [PMID: 37305852 PMCID: PMC10250556 DOI: 10.1016/j.omtm.2023.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 05/12/2023] [Indexed: 06/13/2023]
Abstract
Mutations in the lebercilin-encoding gene LCA5 cause one of the most severe forms of Leber congenital amaurosis, an early-onset retinal disease that results in severe visual impairment. Here, we report on the generation of a patient-specific cellular model to study LCA5-associated retinal disease. CRISPR-Cas9 technology was used to correct a homozygous nonsense variant in LCA5 (c.835C>T; p.Q279∗) in patient-derived induced pluripotent stem cells (iPSCs). The absence of off-target editing in gene-corrected (isogenic) control iPSCs was demonstrated by whole-genome sequencing. We differentiated the patient, gene-corrected, and unrelated control iPSCs into three-dimensional retina-like cells, so-called retinal organoids. We observed opsin and rhodopsin mislocalization to the outer nuclear layer in patient-derived but not in the gene-corrected or unrelated control organoids. We also confirmed the rescue of lebercilin expression and localization along the ciliary axoneme within the gene-corrected organoids. Here, we show the potential of combining precise single-nucleotide gene editing with the iPSC-derived retinal organoid system for the generation of a cellular model of early-onset retinal disease.
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Affiliation(s)
- Tess A.V. Afanasyeva
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GD Nijmegen, the Netherlands
| | | | | | - Kae R. Whiting
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Lonneke Duijkers
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Galuh D.N. Astuti
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Jean Bennett
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Alejandro Garanto
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Department of Paediatrics, Amalia Children’s Hospital, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | | | - Ronald Roepman
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | | | - Rob W.J. Collin
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GD Nijmegen, the Netherlands
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5
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Argyriou C, Polosa A, Song JY, Omri S, Steele B, Cécyre B, McDougald DS, Di Pietro E, Bouchard JF, Bennett J, Hacia JG, Lachapelle P, Braverman NE. AAV-mediated PEX1 gene augmentation improves visual function in the PEX1-Gly844Asp mouse model for mild Zellweger spectrum disorder. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 23:225-240. [PMID: 34703844 PMCID: PMC8516995 DOI: 10.1016/j.omtm.2021.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 09/01/2021] [Indexed: 12/01/2022]
Abstract
Patients with Zellweger spectrum disorder (ZSD) commonly present with vision loss due to mutations in PEX genes required for peroxisome assembly and function. Here, we evaluate PEX1 retinal gene augmentation therapy in a mouse model of mild ZSD bearing the murine equivalent (PEX1-p[Gly844Asp]) of the most common human mutation. Experimental adeno-associated virus 8.cytomegalovirus.human PEX1.hemagglutinin (AAV8.CMV.HsPEX1.HA) and control AAV8.CMV.EGFP vectors were administered by subretinal injection in contralateral eyes of early (5-week-old)- or later (9-week-old)-stage retinopathy cohorts. HsPEX1.HA protein was expressed in the retina with no gross histologic side effects. Peroxisomal metabolic functions, assessed by retinal C26:0 lysophosphatidylcholine (lyso-PC) levels, were partially normalized after therapeutic vector treatment. Full-field flash electroretinogram (ffERG) analyses at 8 weeks post-injection showed a 2-fold improved retinal response in the therapeutic relative to control vector-injected eyes. ffERG improved by 1.6- to 2.5-fold in the therapeutic vector-injected eyes when each cohort reached 25 weeks of age. At 32 weeks of age, the average ffERG response was double in the therapeutic relative to control vector-injected eyes in both cohorts. Optomotor reflex analyses trended toward improvement. These proof-of-concept studies represent the first application of gene augmentation therapy to treat peroxisome biogenesis disorders and support the potential for retinal gene delivery to improve vision in these patients.
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Affiliation(s)
- Catherine Argyriou
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Anna Polosa
- Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Ji Yun Song
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Samy Omri
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Bradford Steele
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Bruno Cécyre
- School of Optometry, Université de Montréal, Montreal, QC, Canada
| | - Devin S McDougald
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erminia Di Pietro
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | | | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph G Hacia
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Pierre Lachapelle
- Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Nancy E Braverman
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
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Datta P, Ruffcorn A, Seo S. Limited time window for retinal gene therapy in a preclinical model of ciliopathy. Hum Mol Genet 2021; 29:2337-2352. [PMID: 32568387 DOI: 10.1093/hmg/ddaa124] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 05/04/2020] [Accepted: 06/15/2020] [Indexed: 12/15/2022] Open
Abstract
Retinal degeneration is a common clinical feature of ciliopathies, a group of genetic diseases linked to ciliary dysfunction, and gene therapy is an attractive treatment option to prevent vision loss. Although the efficacy of retinal gene therapy is well established by multiple proof-of-concept preclinical studies, its long-term effect, particularly when treatments are given at advanced disease stages, is controversial. Incomplete treatment and intrinsic variability of gene delivery methods may contribute to the variable outcomes. Here, we used a genetic rescue approach to 'optimally' treat retinal degeneration at various disease stages and examined the long-term efficacy of gene therapy in a mouse model of ciliopathy. We used a Bardet-Biedl syndrome type 17 (BBS17) mouse model, in which the gene-trap that suppresses Bbs17 (also known as Lztfl1) expression can be removed by tamoxifen administration, restoring normal gene expression systemically. Our data indicate that therapeutic effects of retinal gene therapy decrease gradually as treatments are given at later stages. These results suggest the presence of limited time window for successful gene therapy in certain retinal degenerations. Our study also implies that the long-term efficacy of retinal gene therapy may depend on not only the timing of treatment but also other factors such as the function of mutated genes and residual activities of mutant alleles.
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Affiliation(s)
- Poppy Datta
- 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
| | - Avri Ruffcorn
- 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
| | - Seongjin Seo
- 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
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Chan YK, Dick AD, Hall SM, Langmann T, Scribner CL, Mansfield BC. Inflammation in Viral Vector-Mediated Ocular Gene Therapy: A Review and Report From a Workshop Hosted by the Foundation Fighting Blindness, 9/2020. Transl Vis Sci Technol 2021; 10:3. [PMID: 34003982 PMCID: PMC8024774 DOI: 10.1167/tvst.10.4.3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
On September 14–15, 2020, the Foundation Fighting Blindness convened a virtual workshop to discuss intraocular inflammation during viral vector-mediated gene therapy for inherited retinal diseases. The workshop's goals were to understand immune activation's nature and significance during ocular gene therapy, consider whether ocular inflammation limits gene therapy's potential, and identify knowledge gaps for future research. The event brought together a small group of experienced researchers in the field to present and discuss current data. Collectively, participants agreed that clinical, as well as subclinical, inflammation during ocular gene therapy is common. The severity of inflammation in both animal and clinical studies varied widely but is generally related to vector dose. Severe inflammation was associated with reduced gene therapy efficacy. However, the relationship between outcomes and subclinical inflammation, pre-existing antivector antibodies, or induced adaptive immune responses is still unclear. Uncertainties about the contribution of vector manufacturing issues to inflammation were also noted. Importantly, various immunosuppressive treatment protocols are being used, and this heterogeneity confounds conclusions about optimal strategies. Proposed near-term next steps include establishing an immunological consultant directory, establishing a data repository for pertinent animal and clinical data, and developing a larger meeting. Priority areas for future research include deeper understanding of immune activation during retinal diseases and during ocular gene therapy; better, harmonized application of animal models; and identifying best practices for managing gene therapy vector-related ocular inflammation.
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Affiliation(s)
| | - Andrew D Dick
- UCL Institute of Ophthalmology, London, UK.,University of Bristol, Bristol, UK
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Duong Phu M, Bross S, Burkhalter MD, Philipp M. Limitations and opportunities in the pharmacotherapy of ciliopathies. Pharmacol Ther 2021; 225:107841. [PMID: 33771583 DOI: 10.1016/j.pharmthera.2021.107841] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/11/2021] [Indexed: 01/10/2023]
Abstract
Ciliopathies are a family of rather diverse conditions, which have been grouped based on the finding of altered or dysfunctional cilia, potentially motile, small cellular antennae extending from the surface of postmitotic cells. Cilia-related disorders include embryonically arising conditions such as Joubert, Usher or Kartagener syndrome, but also afflictions with a postnatal or even adult onset phenotype, i.e. autosomal dominant polycystic kidney disease. The majority of ciliopathies are syndromic rather than affecting only a single organ due to cilia being found on almost any cell in the human body. Overall ciliopathies are considered rare diseases. Despite that, pharmacological research and the strive to help these patients has led to enormous therapeutic advances in the last decade. In this review we discuss new treatment options for certain ciliopathies, give an outlook on promising future therapeutic strategies, but also highlight the limitations in the development of therapeutic approaches of ciliopathies.
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Affiliation(s)
- Max Duong Phu
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany
| | - Stefan Bross
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany
| | - Martin D Burkhalter
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany
| | - Melanie Philipp
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany.
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Uyhazi KE, Aravand P, Bell BA, Wei Z, Leo L, Serrano LW, Pearson DJ, Shpylchak I, Pham J, Vasireddy V, Bennett J, Aleman TS. Treatment Potential for LCA5-Associated Leber Congenital Amaurosis. Invest Ophthalmol Vis Sci 2020; 61:30. [PMID: 32428231 PMCID: PMC7405811 DOI: 10.1167/iovs.61.5.30] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/16/2020] [Indexed: 12/17/2022] Open
Abstract
Purpose To determine the therapeutic window for gene augmentation for Leber congenital amaurosis (LCA) associated with mutations in LCA5. Methods Five patients (ages 6-31) with LCA and biallelic LCA5 mutations underwent an ophthalmic examination including optical coherence tomography (SD-OCT), full-field stimulus testing (FST), and pupillometry. The time course of photoreceptor degeneration in the Lca5gt/gt mouse model and the efficacy of subretinal gene augmentation therapy with AAV8-hLCA5 delivered at postnatal day 5 (P5) (early, n = 11 eyes), P15 (mid, n = 14), and P30 (late, n = 13) were assessed using SD-OCT, histologic study, electroretinography (ERG), and pupillometry. Comparisons were made with the human disease. Results Patients with LCA5-LCA showed a maculopathy with detectable outer nuclear layer (ONL) in the pericentral retina and at least 4 log units of dark-adapted sensitivity loss. The Lca5gt/gt mouse has a similarly severe and rapid photoreceptor degeneration. The ONL became progressively thinner and was undetectable by P60. Rod- and cone-mediated ERGs were severely reduced in amplitudes at P30 and became nondetectable by P60. Subretinal AAV8-hLCA5 administered to Lca5gt/gt mice at P5 and P15, but not at P30, resulted in structural and functional rescue. Conclusions LCA5-LCA is a particularly severe form of LCA that was recapitulated in the Lca5gt/gt mouse. Gene augmentation resulted in structural and functional rescue in the Lca5gt/gt mouse if delivered before P30. Retained photoreceptors were visible within the central retina in all patients with LCA5-LCA, at a level equivalent to that observed in rescued Lca5gt/gt mice, suggesting a window of opportunity for the treatment of patients with LCA5-LCA.
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Affiliation(s)
- Katherine E. Uyhazi
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
- Scheie Eye Institute at The Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Puya Aravand
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Brent A. Bell
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Zhangyong Wei
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Lanfranco Leo
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Leona W. Serrano
- Scheie Eye Institute at The Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Denise J. Pearson
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
- Scheie Eye Institute at The Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ivan Shpylchak
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jennifer Pham
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Vidyullatha Vasireddy
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Tomas S. Aleman
- Center for Advanced Retinal and Ocular Therapeutics (CAROT) and F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
- Scheie Eye Institute at The Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Balancing the Photoreceptor Proteome: Proteostasis Network Therapeutics for Inherited Retinal Disease. Genes (Basel) 2019; 10:genes10080557. [PMID: 31344897 PMCID: PMC6722924 DOI: 10.3390/genes10080557] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/09/2019] [Accepted: 07/16/2019] [Indexed: 12/17/2022] Open
Abstract
The light sensing outer segments of photoreceptors (PRs) are renewed every ten days due to their high photoactivity, especially of the cones during daytime vision. This demands a tremendous amount of energy, as well as a high turnover of their main biosynthetic compounds, membranes, and proteins. Therefore, a refined proteostasis network (PN), regulating the protein balance, is crucial for PR viability. In many inherited retinal diseases (IRDs) this balance is disrupted leading to protein accumulation in the inner segment and eventually the death of PRs. Various studies have been focusing on therapeutically targeting the different branches of the PR PN to restore the protein balance and ultimately to treat inherited blindness. This review first describes the different branches of the PN in detail. Subsequently, insights are provided on how therapeutic compounds directed against the different PN branches might slow down or even arrest the appalling, progressive blinding conditions. These insights are supported by findings of PN modulators in other research disciplines.
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Wheway G, Mitchison HM. Opportunities and Challenges for Molecular Understanding of Ciliopathies-The 100,000 Genomes Project. Front Genet 2019; 10:127. [PMID: 30915099 PMCID: PMC6421331 DOI: 10.3389/fgene.2019.00127] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 02/05/2019] [Indexed: 01/11/2023] Open
Abstract
Cilia are highly specialized cellular organelles that serve multiple functions in human development and health. Their central importance in the body is demonstrated by the occurrence of a diverse range of developmental disorders that arise from defects of cilia structure and function, caused by a range of different inherited mutations found in more than 150 different genes. Genetic analysis has rapidly advanced our understanding of the cell biological basis of ciliopathies over the past two decades, with more recent technological advances in genomics rapidly accelerating this progress. The 100,000 Genomes Project was launched in 2012 in the UK to improve diagnosis and future care for individuals affected by rare diseases like ciliopathies, through whole genome sequencing (WGS). In this review we discuss the potential promise and medical impact of WGS for ciliopathies and report on current progress of the 100,000 Genomes Project, reviewing the medical, technical and ethical challenges and opportunities that new, large scale initiatives such as this can offer.
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Affiliation(s)
- Gabrielle Wheway
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, United Kingdom
| | - Hannah M. Mitchison
- Genetics and Genomic Medicine, University College London, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
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12
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Comparative AAV-eGFP Transgene Expression Using Vector Serotypes 1-9, 7m8, and 8b in Human Pluripotent Stem Cells, RPEs, and Human and Rat Cortical Neurons. Stem Cells Int 2019; 2019:7281912. [PMID: 30800164 PMCID: PMC6360060 DOI: 10.1155/2019/7281912] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 10/30/2018] [Accepted: 11/16/2018] [Indexed: 01/03/2023] Open
Abstract
Recombinant adeno-associated virus (rAAV), produced from a nonpathogenic parvovirus, has become an increasing popular vector for gene therapy applications in human clinical trials. However, transduction and transgene expression of rAAVs can differ across in vitro and ex vivo cellular transduction strategies. This study compared 11 rAAV serotypes, carrying one reporter transgene cassette containing a cytomegalovirus immediate-early enhancer (eCMV) and chicken beta actin (CBA) promoter driving the expression of an enhanced green-fluorescent protein (eGFP) gene, which was transduced into four different cell types: human iPSC, iPSC-derived RPE, iPSC-derived cortical, and dissociated embryonic day 18 rat cortical neurons. Each cell type was exposed to three multiplicity of infections (MOI: 1E4, 1E5, and 1E6 vg/cell). After 24, 48, 72, and 96 h posttransduction, GFP-expressing cells were examined and compared across dosage, time, and cell type. Retinal pigmented epithelium showed highest AAV-eGFP expression and iPSC cortical the lowest. At an MOI of 1E6 vg/cell, all serotypes show measurable levels of AAV-eGFP expression; moreover, AAV7m8 and AAV6 perform best across MOI and cell type. We conclude that serotype tropism is not only capsid dependent but also cell type plays a significant role in transgene expression dynamics.
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