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Murgiano L, Niggel JK, Benedicenti L, Cortellari M, Bionda A, Crepaldi P, Liotta L, Aguirre GK, Beltran WA, Aguirre GD. Frameshift Variant in AMPD2 in Cirneco dell'Etna Dogs with Retinopathy and Tremors. Genes (Basel) 2024; 15:238. [PMID: 38397227 PMCID: PMC10887799 DOI: 10.3390/genes15020238] [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: 01/01/2024] [Revised: 02/08/2024] [Accepted: 02/10/2024] [Indexed: 02/25/2024] Open
Abstract
While the manifestations of many inherited retinal disorders are limited to loss of vision, others are part of a syndrome that affects multiple tissues, particularly the nervous system. Most syndromic retinal disorders are thought to be recessively inherited. Two dogs out of a litter of Cirneco dell' Etna dogs, both males, showed signs of retinal degeneration, along with tremors and signs described as either atypical seizures or paroxysmal dyskinesias, while the other two male littermates were normal. We named this oculo-neurological syndrome CONS (Cirneco oculo-neurological syndrome), and undertook homozygosity mapping and whole-genome sequencing to determine its potential genetic etiology. Notably, we detected a 1-bp deletion in chromosome 6 that was predicted to cause a frameshift and premature stop codon within the canine AMPD2 gene, which encodes adenosine monophosphate deaminase, an enzyme that converts adenosine 5'-monophosphate (AMP) to inosine 5'-monophosphate (IMP). Genotyping of the available Cirneco population suggested perfect segregation between cases and controls for the variant. Moreover, this variant was absent in canine genomic databases comprised of thousands of unaffected dogs. The AMPD2 genetic variant we identified in dogs presents with retinal manifestations, adding to the spectrum of neurological manifestations associated with AMPD2 variants in humans.
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Affiliation(s)
- Leonardo Murgiano
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.K.N.); (W.A.B.); (G.D.A.)
- Sylvia M. Van Sloun Laboratory for Canine Genomic Analysis, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jessica K. Niggel
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.K.N.); (W.A.B.); (G.D.A.)
- Sylvia M. Van Sloun Laboratory for Canine Genomic Analysis, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Leontine Benedicenti
- Matthew J. Ryan Veterinary Hospital, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Matteo Cortellari
- Department of Agricultural and Environmental Sciences—Production, Territory, Agroenergy, University of Milan, 20133 Milan, Italy; (M.C.); (A.B.); (P.C.)
| | - Arianna Bionda
- Department of Agricultural and Environmental Sciences—Production, Territory, Agroenergy, University of Milan, 20133 Milan, Italy; (M.C.); (A.B.); (P.C.)
| | - Paola Crepaldi
- Department of Agricultural and Environmental Sciences—Production, Territory, Agroenergy, University of Milan, 20133 Milan, Italy; (M.C.); (A.B.); (P.C.)
| | - Luigi Liotta
- Department of Veterinary Sciences, University of Messina, 98168 Messina, Italy;
| | - Geoffrey K. Aguirre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - William A. Beltran
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.K.N.); (W.A.B.); (G.D.A.)
| | - Gustavo D. Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (J.K.N.); (W.A.B.); (G.D.A.)
- Sylvia M. Van Sloun Laboratory for Canine Genomic Analysis, University of Pennsylvania, Philadelphia, PA 19104, USA
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2
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Nguyen XTA, Moekotte L, Plomp AS, Bergen AA, van Genderen MM, Boon CJF. Retinitis Pigmentosa: Current Clinical Management and Emerging Therapies. Int J Mol Sci 2023; 24:ijms24087481. [PMID: 37108642 PMCID: PMC10139437 DOI: 10.3390/ijms24087481] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/01/2023] [Accepted: 04/15/2023] [Indexed: 04/29/2023] Open
Abstract
Retinitis pigmentosa (RP) comprises a group of inherited retinal dystrophies characterized by the degeneration of rod photoreceptors, followed by the degeneration of cone photoreceptors. As a result of photoreceptor degeneration, affected individuals experience gradual loss of visual function, with primary symptoms of progressive nyctalopia, constricted visual fields and, ultimately, central vision loss. The onset, severity and clinical course of RP shows great variability and unpredictability, with most patients already experiencing some degree of visual disability in childhood. While RP is currently untreatable for the majority of patients, significant efforts have been made in the development of genetic therapies, which offer new hope for treatment for patients affected by inherited retinal dystrophies. In this exciting era of emerging gene therapies, it remains imperative to continue supporting patients with RP using all available options to manage their condition. Patients with RP experience a wide variety of physical, mental and social-emotional difficulties during their lifetime, of which some require timely intervention. This review aims to familiarize readers with clinical management options that are currently available for patients with RP.
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Affiliation(s)
- Xuan-Thanh-An Nguyen
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Lude Moekotte
- Department of Ophthalmology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Astrid S Plomp
- Department of Clinical Genetics, Amsterdam University Medical Centers, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Arthur A Bergen
- Department of Clinical Genetics, Amsterdam University Medical Centers, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Maria M van Genderen
- Department of Ophthalmology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
- Bartiméus, Diagnostic Center for Complex Visual Disorders, 3703 AJ Zeist, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Department of Ophthalmology, Amsterdam University Medical Centers, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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3
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Su J, She K, Song L, Jin X, Li R, Zhao Q, Xiao J, Chen D, Cheng H, Lu F, Wei Y, Yang Y. In vivo base editing rescues photoreceptors in a mouse model of retinitis pigmentosa. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 31:596-609. [PMID: 36910709 PMCID: PMC9996133 DOI: 10.1016/j.omtn.2023.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 02/11/2023] [Indexed: 02/16/2023]
Abstract
Retinitis pigmentosa (RP) is a group of retinal diseases that cause the progressive death of retinal photoreceptor cells and eventually blindness. Mutations in the β-domain of the phosphodiesterase 6 (Pde6b) gene are the most identified causes of autosomal recessive RP. Clinically, there is no effective treatment so far that can stop the progression of RP and restore the vision. Here, we report a base editing approach in which adeno-associated virus (AAV)-mediated adenine base editor (ABE) delivering to postmitotic photoreceptors was conducted to correct the Pde6b mutation in a retinal degeneration 10 (rd10) mouse model of RP. Subretinal delivery of AAV8-ABE corrected Pde6b mutation with averaging up to 20.79% efficiency at the DNA level and 54.97% efficiency at the cDNA level without bystanders, restored PDE6B expression, preserved photoreceptors, and rescued visual function. RNA-seq revealed the preservation of genes associated with phototransduction and photoreceptor survival. Our data have demonstrated that base editing is a potential gene therapy that could provide durable protection against RP.
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Affiliation(s)
- Jing Su
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, Sichuan, China
| | - Kaiqin She
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Li Song
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, Sichuan, China
| | - Xiu Jin
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, Sichuan, China
| | - Ruiting Li
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, Sichuan, China
| | - Qinyu Zhao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, Sichuan, China
| | - Jianlu Xiao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, Sichuan, China
| | - Danian Chen
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Hui Cheng
- Institute of Rare Diseases, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Fang Lu
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yuquan Wei
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, Sichuan, China
| | - Yang Yang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.,State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, Sichuan, China
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4
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Stanton AC, Lagerborg KA, Tellez L, Krunnfusz A, King EM, Ye S, Solomon IH, Tabebordbar M, Sabeti PC. Systemic administration of novel engineered AAV capsids facilitates enhanced transgene expression in the macaque CNS. MED 2023; 4:31-50.e8. [PMID: 36417917 PMCID: PMC9840684 DOI: 10.1016/j.medj.2022.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 10/31/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022]
Abstract
BACKGROUND Adeno-associated virus (AAV) vectors are a promising vehicle for noninvasive gene delivery to the central nervous system via intravenous infusion. However, naturally occurring serotypes have a limited ability to transduce the brain, and translating engineered capsids from mice to nonhuman primates has proved challenging. METHODS In this study, we use an mRNA-based directed-evolution strategy in multiple strains of mice as well as a de novo selection in cynomolgus macaques to identify families of engineered vectors with increased potency in the brain and decreased tropism for the liver. FINDINGS We compare the transgene expression capabilities of several engineered vectors and show that while some of our novel macaque-derived variants significantly outperform AAV9 in transducing the macaque brain following systemic administration, mouse-derived variants-both those identified in this study and those reported by other groups-universally do not. CONCLUSIONS Together, the results of this work introduce a class of primate-derived engineered AAV capsids with increased therapeutic potential and highlight the critical need for using appropriate animal models to both identify and evaluate novel AAVs intended for delivery to the human central nervous system. FUNDING This work was funded primarily through an anonymous philanthropic gift to the P.C.S. lab at the Broad Institute of MIT and Harvard and by a grant from the Howard Hughes Medical Institute to P.C.S.
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Affiliation(s)
- Alexandra C. Stanton
- Broad Institute of MIT and Harvard, Cambridge, MA, USA 02142,Harvard Program in Virology, Harvard Medical School, Boston, MA, USA 02115,Lead Contact,Correspondence: (A.C.S); (P.C.S.)
| | - Kim A. Lagerborg
- Broad Institute of MIT and Harvard, Cambridge, MA, USA 02142,Harvard Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, USA 02115
| | - Liana Tellez
- Broad Institute of MIT and Harvard, Cambridge, MA, USA 02142
| | | | - Emily M. King
- Broad Institute of MIT and Harvard, Cambridge, MA, USA 02142
| | - Simon Ye
- Broad Institute of MIT and Harvard, Cambridge, MA, USA 02142,Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA 02142
| | - Isaac H. Solomon
- Harvard Medical School, Boston, MA, USA 02115,Department of Pathology, Brigham and Women’s Hospital, Boston, MA, USA 02115
| | | | - Pardis C. Sabeti
- Broad Institute of MIT and Harvard, Cambridge, MA, USA 02142,Department of Organismic and Evolutionary Biology, FAS Center for Systems Biology, Harvard University, Cambridge, MA, USA 02138,Correspondence: (A.C.S); (P.C.S.)
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5
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Badiei A, Beltran WA, Aguirre GD. Altered transsulfuration pathway enzymes and redox homeostasis in inherited retinal degenerative diseases. Exp Eye Res 2022; 215:108902. [PMID: 34954206 PMCID: PMC8923955 DOI: 10.1016/j.exer.2021.108902] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/04/2021] [Accepted: 12/15/2021] [Indexed: 02/03/2023]
Abstract
Retinal degenerative diseases result from apoptotic photoreceptor cell death. As endogenously produced gaseous molecules such as hydrogen sulfide (H2S) and nitric oxide (NO) play a key role in apoptosis, we compared the expression levels of genes and proteins involved in the production of these molecules in the retina of normal dogs and three canine models (rcd1, crd2, and xlpra2) of human inherited retinal degeneration (IRD). Using qRT-PCR, Western blot, and immunohistochemistry (IHC), we showed that mRNA and protein levels of cystathionine β-synthase (CBS), an enzyme that produces H2S in neurons, are increased in retinal degeneration, but those of cystathionine γ-lyase (CSE), an enzyme involved in the production of glutathione (GSH), an antioxidant, are not. Such findings suggest that increased levels of H2S that are not counterbalanced by increased antioxidant potential may contribute to disease in affected retinas. We also studied the expression of neuronal and inducible nitric oxide synthase (nNOS and iNOS), the enzymes responsible for NO production. Western blot and IHC results revealed increased levels of nNOS and iNOS, resulting in increased NO levels in mutant retinas. Finally, photoreceptors are rich in polyunsaturated fatty acids (PUFAs) that can make these cells vulnerable to oxidative damage through reactive oxygen species (ROS). Our results showed increased levels of acrolein and hydroxynonenal (4HNE), two main toxic products of PUFAs, surrounding the membranes of photoreceptors in affected canines. Increased levels of these toxic products, together with increased NO and ROS, likely render these cells susceptible to an intrinsic apoptotic pathway involving mitochondrial membranes. To assess this possibility, we measured the levels of BCL2, an anti-apoptotic protein in the mitochondrial membrane. Western blot results showed decreased levels of BCL2 protein in affected retinas. Overall, the results of this study identify alterations in the expression of enzymes directly involved in maintaining the normal redox status of the retina during retinal degeneration, thereby supporting future studies to investigate the role of H2S and NO in retinal degeneration and apoptosis.
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Affiliation(s)
- Alireza Badiei
- Department of Veterinary Medicine, College of Natural Science and Mathematics, University of Alaska Fairbanks, AK, USA; Division of Experimental Retinal Therapies, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - William A Beltran
- Division of Experimental Retinal Therapies, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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6
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Nguyen XTA, Talib M, van Schooneveld MJ, Wijnholds J, van Genderen MM, Schalij-Delfos NE, Klaver CCW, Talsma HE, Fiocco M, Florijn RJ, Ten Brink JB, Cremers FPM, Meester-Smoor MA, van den Born LI, Hoyng CB, Thiadens AAHJ, Bergen AA, Boon CJF. CRB1-Associated Retinal Dystrophies: A Prospective Natural History Study in Anticipation of Future Clinical Trials. Am J Ophthalmol 2022; 234:37-48. [PMID: 34320374 DOI: 10.1016/j.ajo.2021.07.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 07/15/2021] [Accepted: 07/15/2021] [Indexed: 12/28/2022]
Abstract
PURPOSE To investigate the natural disease course of retinal dystrophies associated with crumbs cell polarity complex component 1 (CRB1) and identify clinical end points for future clinical trials. DESIGN Single-center, prospective case series. METHODS An investigator-initiated nationwide collaborative study that included 22 patients with CRB1-associated retinal dystrophies. Patients underwent ophthalmic assessment at baseline and 2 years after baseline. Clinical examination included best-corrected visual acuity (BCVA) using Early Treatment Diabetic Retinopathy Study charts, Goldmann kinetic perimetry (V4e isopter seeing retinal areas), microperimetry, full-field electroretinography, full-field stimulus threshold (FST), fundus photography, spectral-domain optical coherence tomography, and fundus autofluorescence imaging. RESULTS Based on genetic, clinical, and electrophysiological data, patients were diagnosed with retinitis pigmentosa (19 [86%]), cone-rod dystrophy (2 [9%]), or isolated macular dystrophy (1 [5%]). Analysis of the entire cohort at 2 years showed no significant changes in BCVA (P = .069) or V4e isopter seeing retinal areas (P = .616), although signs of clinical progression were present in individual patients. Macular sensitivity measured on microperimetry revealed a significant reduction at the 2-year follow-up (P < .001). FST responses were measurable in patients with nonrecordable electroretinograms. On average, FST responses remained stable during follow-up. CONCLUSION In CRB1-associated retinal dystrophies, visual acuity and visual field measures remain relatively stable over the course of 2 years. Microperimetry showed a significant decrease in retinal sensitivity during follow-up and may be a more sensitive progression marker. Retinal sensitivity on microperimetry may serve as a functional clinical end point in future human treatment trials for CRB1-associated retinal dystrophies.
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Affiliation(s)
- Xuan-Thanh-An Nguyen
- From the Department of Ophthalmology (X.-T.-A.N., M.T., J.W., N.E.S.-D., H.E.T., C.J.F.B.), Leiden University Medical Center, Leiden, the Netherlands
| | - Mays Talib
- From the Department of Ophthalmology (X.-T.-A.N., M.T., J.W., N.E.S.-D., H.E.T., C.J.F.B.), Leiden University Medical Center, Leiden, the Netherlands
| | - Mary J van Schooneveld
- Department of Ophthalmology (M.J.v.S., C.J.F.B.), Amsterdam University Medical Center (UMC), Academic Medical Center, Amsterdam, the Netherlands
| | - Jan Wijnholds
- From the Department of Ophthalmology (X.-T.-A.N., M.T., J.W., N.E.S.-D., H.E.T., C.J.F.B.), Leiden University Medical Center, Leiden, the Netherlands; The Netherlands Institute for Neuroscience (NIN-KNAW) (J.W., A.A.B.), Amsterdam, the Netherlands
| | - Maria M van Genderen
- Bartiméus Diagnostic Centre for Complex Visual Disorders (M.M.v.G., H.E.T.), Zeist, the Netherlands; Department of Ophthalmology (M.M.v.G.), University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Nicoline E Schalij-Delfos
- From the Department of Ophthalmology (X.-T.-A.N., M.T., J.W., N.E.S.-D., H.E.T., C.J.F.B.), Leiden University Medical Center, Leiden, the Netherlands
| | - Caroline C W Klaver
- Department of Ophthalmology (C.C.W.K., M.A.M.-S., A.A.H.J.T.); Department of Epidemiology (C.C.W.K.), Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Ophthalmology (C.C.W.K., C.B.H.), Radboud University Medical Center, Nijmegen, the Netherlands; Institute for Molecular and Clinical Ophthalmology (C.C.W.K.), Basel, Switzerland
| | - Herman E Talsma
- From the Department of Ophthalmology (X.-T.-A.N., M.T., J.W., N.E.S.-D., H.E.T., C.J.F.B.), Leiden University Medical Center, Leiden, the Netherlands; Bartiméus Diagnostic Centre for Complex Visual Disorders (M.M.v.G., H.E.T.), Zeist, the Netherlands
| | - Marta Fiocco
- Mathematical Institute (M.F.), and Department of Biomedical Data Sciences (M.F.), Leiden University Medical Center, Leiden, the Netherlands
| | - Ralph J Florijn
- Department of Clinical Genetics (R.J.F., J.B.t.B., A.A.B.), Amsterdam University Medical Center (UMC), Academic Medical Center, Amsterdam, the Netherlands
| | - Jacoline B Ten Brink
- Department of Clinical Genetics (R.J.F., J.B.t.B., A.A.B.), Amsterdam University Medical Center (UMC), Academic Medical Center, Amsterdam, the Netherlands
| | - Frans P M Cremers
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour (F.P.M.C.), Radboud University Medical Center, Nijmegen, the Netherlands
| | | | | | - Carel B Hoyng
- Department of Ophthalmology (C.C.W.K., C.B.H.), Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Arthur A Bergen
- The Netherlands Institute for Neuroscience (NIN-KNAW) (J.W., A.A.B.), Amsterdam, the Netherlands; Department of Clinical Genetics (R.J.F., J.B.t.B., A.A.B.), Amsterdam University Medical Center (UMC), Academic Medical Center, Amsterdam, the Netherlands
| | - Camiel J F Boon
- From the Department of Ophthalmology (X.-T.-A.N., M.T., J.W., N.E.S.-D., H.E.T., C.J.F.B.), Leiden University Medical Center, Leiden, the Netherlands; Department of Ophthalmology (M.J.v.S., C.J.F.B.), Amsterdam University Medical Center (UMC), Academic Medical Center, Amsterdam, the Netherlands.
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7
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Prabhakaran GT, Al-Nosairy KO, Tempelmann C, Thieme H, Hoffmann MB. Mapping Visual Field Defects With fMRI - Impact of Approach and Experimental Conditions. Front Neurosci 2021; 15:745886. [PMID: 34566575 PMCID: PMC8455880 DOI: 10.3389/fnins.2021.745886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 08/19/2021] [Indexed: 11/13/2022] Open
Abstract
Current initiatives to restore vision emphasize the need for objective assessments of visual field (VF) defects as pursued with functional magnetic resonance imaging (fMRI) approaches. Here, we compared population receptive field (pRF) mapping-based VF reconstructions to an fMRI method that uses more robust visual stimulation (on-off block design) in combination with individualized anatomy-driven retinotopic atlas-information (atlas-based VF). We investigated participants with sizable peripheral VF-deficits due to advanced glaucoma (n = 4) or retinitis pigmentosa (RP; n = 2) and controls (n = 6) with simulated scotoma. We obtained (1) standard automated perimetry (SAP) data as reference VFs and 3T fMRI data for (2) pRF-mapping [8-direction bar stimulus, fixation color change task] and (3) block-design full-field stimulation [8-direction drifting contrast patterns during (a) passive viewing (PV) and (b) one-back-task (OBT; reporting successions of identical motion directions) to probe the impact of previously reported task-related unspecific visual cortex activations]. Correspondence measures between the SAP and fMRI-based VFs were accuracy, assisted by sensitivity and specificity. We found an accuracy of pRF-based VF from V1 in patients [median: 0.62] that was similar to previous reports and increased by adding V2 and V3 to the analysis [0.74]. In comparison to the pRF-based VF, equivalent accuracies were obtained for the atlas-based VF for both PV [0.67] and, unexpectedly, the OBT [0.59], where, however, unspecific cortical activations were reflected by a reduction in sensitivity [0.71 (PV) and 0.35 (OBT)]. In conclusion, in patients with peripheral VF-defects, we demonstrate that previous fMRI procedures to obtain VF-estimates might be enhanced by: (1) pooling V1-V3 to enhance accuracy; (2) reporting sensitivity and specificity measures to increase transparency of the VF-reconstruction metric; (3) applying atlas-based procedures, if pRF-based VFs are not available or difficult to obtain; and (4) giving, counter-intuitively, preference to PV. These findings are expected to provide guidance to overcome current limitations of translating fMRI-based methods to a clinical work-up.
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Affiliation(s)
| | | | - Claus Tempelmann
- Department of Neurology, Otto von Guericke University, Magdeburg, Germany
| | - Hagen Thieme
- Department of Ophthalmology, Otto von Guericke University, Magdeburg, Germany
| | - Michael B Hoffmann
- Department of Ophthalmology, Otto von Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
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8
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Prabhakaran GT, Al-Nosairy KO, Tempelmann C, Wagner M, Thieme H, Hoffmann MB. Functional Dynamics of Deafferented Early Visual Cortex in Glaucoma. Front Neurosci 2021; 15:653632. [PMID: 34381327 PMCID: PMC8350780 DOI: 10.3389/fnins.2021.653632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 06/23/2021] [Indexed: 12/03/2022] Open
Abstract
In advanced retinitis pigmentosa with retinal lesions, the lesion projection zone (LPZ) in the early visual cortex can be driven during visual tasks, while it remains unresponsive during passive viewing. We tested whether this finding translates to advanced glaucoma, a major cause of acquired blindness. During visual stimulation, 3T fMRI scans were acquired for participants with advanced glaucoma (n = 4; age range: 51–72) and compared to two reference groups, i.e., advanced retinitis pigmentosa (n = 3; age range: 46–78) and age-matched healthy controls with simulated defects (n = 7). The participants viewed grating patterns drifting in 8 directions (12 s) alternating with uniform gray (12 s), either during passive viewing (PV), i.e., central fixation, or during a one-back task (OBT), i.e., reports of succeeding identical motion directions. As another reference, a fixation-dot task condition was included. Only in glaucoma and retinitis pigmentosa but not in controls, fMRI-responses in the lesion projection zone (LPZ) of V1 shifted from negative for PV to positive for OBT (p = 0.024 and p = 0.012, respectively). In glaucoma, these effects also reached significance in V3 (p = 0.006), while in V2 there was a non-significant trend (p = 0.069). The general absence of positive responses in the LPZ during PV underscores the lack of early visual cortex bottom-up plasticity for acquired visual field defects in humans. Trends in our exploratory analysis suggesting the task-dependent LPZ responses to be inversely related to visual field loss, indicate the benefit of patient stratification strategies in future studies with greater sample sizes. We conclude that top-down mechanisms associated with task-elicited demands rather than visual cortex remapping appear to shape LPZ responses not only in retinitis pigmentosa, but also in glaucoma. These insights are of critical importance for the development of schemes for treatment and rehabilitation in glaucoma and beyond.
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Affiliation(s)
| | | | - Claus Tempelmann
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany
| | - Markus Wagner
- Department of Ophthalmology, Otto-von-Guericke University, Magdeburg, Germany
| | - Hagen Thieme
- Department of Ophthalmology, Otto-von-Guericke University, Magdeburg, Germany
| | - Michael B Hoffmann
- Department of Ophthalmology, Otto-von-Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, Germany
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9
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Hopper RG, Montiani-Ferreira F, da Silva Pereira J, Fritz MC, Ruggiero VJ, Sapienza JS, Kato K, Komáromy AM. Presumed neuroprotective therapies prescribed by veterinary ophthalmologists for canine degenerative retinal and optic nerve diseases. Vet Ophthalmol 2021; 24:229-239. [PMID: 33682296 DOI: 10.1111/vop.12878] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/13/2021] [Accepted: 02/13/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To investigate veterinary ophthalmologists' use of presumed neuroprotective therapies for degenerative retinal and optic nerve diseases in dogs. PROCEDURES An online survey was sent to 663 board-certified veterinary ophthalmologists who were Diplomates of the American College of Veterinary Ophthalmologists (ACVO), Asian College of Veterinary Ophthalmologists (AiCVO), Latin American College of Veterinary Ophthalmologists (Colegio Latinoamericano de Oftalmólogos Veterinarios, CLOVE), or European College of Veterinary Ophthalmologists (ECVO). The survey was created using Qualtrics® software and focused on the prescription of presumed neuroprotective treatments for canine glaucoma, sudden acquired retinal degeneration syndrome (SARDS), progressive retinal atrophy (PRA), and retinal detachment (RD). RESULTS A total of 165 completed surveys were received, representing an overall response rate of 25%, which was comparable across the four specialty colleges. Of all respondents, 140/165 (85%) prescribed some form of presumed neuroprotective therapies at least once in the last five years: 114/165 (69%) for glaucoma, 51/165 (31%) for SARDS, 116/165 (70%) for PRA, and 50/165 (30%) for RD. The three most recommended neuroprotective reagents were the commercial Ocu-GLO™ Vision Supplement for animals, amlodipine, and human eye supplements. CONCLUSIONS Despite lack of published clinical efficacy data, the majority of surveyed board-certified veterinary ophthalmologists previously prescribed a presumed neuroprotective therapy at least once in the last five years in dogs with degenerative retinal and optic nerve diseases.
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Affiliation(s)
- Ryan G Hopper
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | | | - Jorge da Silva Pereira
- Center of Studies, Research, and Veterinary Ophthalmology (CEPOV), Rio de Janeiro, Brazil
| | - Michele C Fritz
- Office of Academic Programs, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Vickie J Ruggiero
- Office of Academic Programs, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | | | | | - András M Komáromy
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
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10
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Komáromy AM, Koehl KL, Park SA. Looking into the future: Gene and cell therapies for glaucoma. Vet Ophthalmol 2021; 24 Suppl 1:16-33. [PMID: 33411993 PMCID: PMC7979454 DOI: 10.1111/vop.12858] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 12/21/2020] [Indexed: 12/17/2022]
Abstract
Glaucoma is a complex group of optic neuropathies that affects both humans and animals. Intraocular pressure (IOP) elevation is a major risk factor that results in the loss of retinal ganglion cells (RGCs) and their axons. Currently, lowering IOP by medical and surgical methods is the only approved treatment for primary glaucoma, but there is no cure, and vision loss often progresses despite therapy. Recent technologic advances provide us with a better understanding of disease mechanisms and risk factors; this will permit earlier diagnosis of glaucoma and initiation of therapy sooner and more effectively. Gene and cell therapies are well suited to target these mechanisms specifically with the potential to achieve a lasting therapeutic effect. Much progress has been made in laboratory settings to develop these novel therapies for the eye. Gene and cell therapies have already been translated into clinical application for some inherited retinal dystrophies and age-related macular degeneration (AMD). Except for the intravitreal application of ciliary neurotrophic factor (CNTF) by encapsulated cell technology for RGC neuroprotection, there has been no other clinical translation of gene and cell therapies for glaucoma so far. Possible application of gene and cell therapies consists of long-term IOP control via increased aqueous humor drainage, including inhibition of fibrosis following filtration surgery, RGC neuroprotection and neuroregeneration, modification of ocular biomechanics for improved IOP tolerance, and inhibition of inflammation and neovascularization to prevent the development of some forms of secondary glaucoma.
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Affiliation(s)
- András M. Komáromy
- College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Kristin L. Koehl
- College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Shin Ae Park
- College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
- College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA
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11
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White KA, Nelvagal HR, Poole TA, Lu B, Johnson TB, Davis S, Pratt MA, Brudvig J, Assis AB, Likhite S, Meyer K, Kaspar BK, Cooper JD, Wang S, Weimer JM. Intracranial delivery of AAV9 gene therapy partially prevents retinal degeneration and visual deficits in CLN6-Batten disease mice. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 20:497-507. [PMID: 33665223 PMCID: PMC7887332 DOI: 10.1016/j.omtm.2020.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 12/31/2020] [Indexed: 02/07/2023]
Abstract
Batten disease is a family of rare, fatal, neuropediatric diseases presenting with memory/learning decline, blindness, and loss of motor function. Recently, we reported the use of an AAV9-mediated gene therapy that prevents disease progression in a mouse model of CLN6-Batten disease (Cln6 nclf ), restoring lifespans in treated animals. Despite the success of our viral-mediated gene therapy, the dosing strategy was optimized for delivery to the brain parenchyma and may limit the therapeutic potential to other disease-relevant tissues, such as the eye. Here, we examine whether cerebrospinal fluid (CSF) delivery of scAAV9.CB.CLN6 is sufficient to ameliorate visual deficits in Cln6 nclf mice. We show that intracerebroventricular (i.c.v.) delivery of scAAV9.CB.CLN6 completely prevents hallmark Batten disease pathology in the visual processing centers of the brain, preserving neurons of the superior colliculus, thalamus, and cerebral cortex. Importantly, i.c.v.-delivered scAAV9.CB.CLN6 also expresses in many cells throughout the central retina, preserving many photoreceptors typically lost in Cln6 nclf mice. Lastly, scAAV9.CB.CLN6 treatment partially preserved visual acuity in Cln6 nclf mice as measured by optokinetic response. Taken together, we report the first instance of CSF-delivered viral gene reaching and rescuing pathology in both the brain parenchyma and retinal neurons, thereby partially slowing visual deterioration.
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Affiliation(s)
- Katherine A White
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Hemanth R Nelvagal
- Pediatric Storage Disorders Laboratory, Division of Genetics and Genomics, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA.,Department of Pediatrics, The Lundquist Institute at Harbor-UCLA Medical Center and David Geffen School of Medicine, UCLA, Torrance, CA 90502, USA
| | - Timothy A Poole
- Pediatric Storage Disorders Laboratory, Division of Genetics and Genomics, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bin Lu
- Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Tyler B Johnson
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA.,Amicus Therapeutics, Philadelphia, PA 19104, USA
| | - Samantha Davis
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Melissa A Pratt
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Jon Brudvig
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Ana B Assis
- Department of Pediatrics, The Lundquist Institute at Harbor-UCLA Medical Center and David Geffen School of Medicine, UCLA, Torrance, CA 90502, USA
| | - Shibi Likhite
- Nationwide Children's Hospital. He was involved in AAV9 construct development
| | - Kathrin Meyer
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA
| | - Brian K Kaspar
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA
| | - Jonathan D Cooper
- Pediatric Storage Disorders Laboratory, Division of Genetics and Genomics, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA.,Department of Pediatrics, The Lundquist Institute at Harbor-UCLA Medical Center and David Geffen School of Medicine, UCLA, Torrance, CA 90502, USA
| | - Shaomei Wang
- Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Jill M Weimer
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA.,Amicus Therapeutics, Philadelphia, PA 19104, USA.,Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57069, USA
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12
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CCDC66 frameshift variant associated with a new form of early-onset progressive retinal atrophy in Portuguese Water Dogs. Sci Rep 2020; 10:21162. [PMID: 33273526 PMCID: PMC7712861 DOI: 10.1038/s41598-020-77980-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 11/10/2020] [Indexed: 11/17/2022] Open
Abstract
Aberrant photoreceptor function or morphogenesis leads to blinding retinal degenerative diseases, the majority of which have a genetic aetiology. A variant in PRCD previously identified in Portuguese Water Dogs (PWDs) underlies prcd (progressive rod-cone degeneration), an autosomal recessive progressive retinal atrophy (PRA) with a late onset at 3–6 years of age or older. Herein, we have identified a new form of early-onset PRA (EOPRA) in the same breed. Pedigree analysis suggested an autosomal recessive inheritance. Four PWD full-siblings affected with EOPRA diagnosed at 2–3 years of age were genotyped (173,661 SNPs) along with 2 unaffected siblings, 2 unaffected parents, and 15 unrelated control PWDs. GWAS, linkage analysis and homozygosity mapping defined a 26-Mb candidate region in canine chromosome 20. Whole-genome sequencing in one affected dog and its obligatory carrier parents identified a 1 bp insertion (CFA20:g.33,717,704_33,717,705insT (CanFam3.1); c.2262_c.2263insA) in CCDC66 predicted to cause a frameshift and truncation (p.Val747SerfsTer8). Screening of an extended PWD population confirmed perfect co-segregation of this genetic variant with the disease. Western blot analysis of COS-1 cells transfected with recombinant mutant CCDC66 expression constructs showed the mutant transcript translated into a truncated protein. Furthermore, in vitro studies suggest that the mutant CCDC66 is mislocalized to the nucleus relative to wild type CCDC66. CCDC66 variants have been associated with inherited retinal degenerations (RDs) including canine and murine ciliopathies. As genetic variants affecting the primary cilium can cause ciliopathies in which RD may be either the sole clinical manifestation or part of a syndrome, our findings further support a role for CCDC66 in retinal function and viability, potentially through its ciliary function.
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13
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Perez-Cervantes C, Smith LA, Nadadur RD, Hughes AEO, Wang S, Corbo JC, Cepko C, Lonfat N, Moskowitz IP. Enhancer transcription identifies cis-regulatory elements for photoreceptor cell types. Development 2020; 147:dev184432. [PMID: 31915147 PMCID: PMC7033740 DOI: 10.1242/dev.184432] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 12/13/2019] [Indexed: 12/30/2022]
Abstract
Identification of cell type-specific cis-regulatory elements (CREs) is crucial for understanding development and disease, although identification of functional regulatory elements remains challenging. We hypothesized that context-specific CREs could be identified by context-specific non-coding RNA (ncRNA) profiling, based on the observation that active CREs produce ncRNAs. We applied ncRNA profiling to identify rod and cone photoreceptor CREs from wild-type and mutant mouse retinas, defined by presence or absence, respectively, of the rod-specific transcription factor (TF) NrlNrl-dependent ncRNA expression strongly correlated with epigenetic profiles of rod and cone photoreceptors, identified thousands of candidate rod- and cone-specific CREs, and identified motifs for rod- and cone-specific TFs. Colocalization of NRL and the retinal TF CRX correlated with rod-specific ncRNA expression, whereas CRX alone favored cone-specific ncRNA expression, providing quantitative evidence that heterotypic TF interactions distinguish cell type-specific CRE activity. We validated the activity of novel Nrl-dependent ncRNA-defined CREs in developing cones. This work supports differential ncRNA profiling as a platform for the identification of cell type-specific CREs and the discovery of molecular mechanisms underlying TF-dependent CRE activity.
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Affiliation(s)
- Carlos Perez-Cervantes
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Linsin A Smith
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Rangarajan D Nadadur
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Andrew E O Hughes
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sui Wang
- Departments of Genetics and Ophthalmology, Howard Hughes Medical Institute, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Joseph C Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Constance Cepko
- Departments of Genetics and Ophthalmology, Howard Hughes Medical Institute, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Nicolas Lonfat
- Departments of Genetics and Ophthalmology, Howard Hughes Medical Institute, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Ivan P Moskowitz
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, IL 60637, USA
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14
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Falasconi A, Biagioni M, Novelli E, Piano I, Gargini C, Strettoi E. Retinal Phenotype in the rd9 Mutant Mouse, a Model of X-Linked RP. Front Neurosci 2019; 13:991. [PMID: 31607844 PMCID: PMC6761883 DOI: 10.3389/fnins.2019.00991] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/03/2019] [Indexed: 12/25/2022] Open
Abstract
Retinal degeneration 9 (rd9) mice carry a mutation in the retina specific “Retinitis Pigmentosa GTPase Regulator (RPGR)” Open Reading Frame (ORF) 15 gene, located on the X chromosome and represent a rare model of X-linked Retinitis Pigmentosa (XLRP), a common and severe form of retinal degeneration (Wright et al., 2010; Tsang and Sharma, 2018). The rd9 RPGR-ORF15 mutation in mice causes lack of the protein in photoreceptors and a slow degeneration of these cells with consequent decrease in Outer Nuclear Layer (ONL) thickness and amplitude of ERG responses, as previously described (Thompson et al., 2012). However, relative rates of rod and cone photoreceptor loss, as well as secondary alterations occurring in neuronal and non-neuronal retinal cell types of rd9 mutants remain to be assessed. Aim of this study is to extend phenotype analysis of the rd9 mouse retina focusing on changes occurring in cells directly interacting with photoreceptors. To this purpose, first we estimated rod and cone survival and its degree of intraretinal variation over time; then, we studied the morphology of horizontal and bipolar cells and of the retinal pigment epithelium (RPE), extending our observations to glial cell reactivity. We found that in rd9 retinas rod (but not cone) death is the main cause of decrease in ONL thickness and that degeneration shows a high degree of intraretinal variation. Rod loss drives remodeling in the outer retina, with sprouting of second-order neurons of the rod-pathway and relative sparing of cone pathway elements. Remarkably, despite cone survival, functional defects can be clearly detected in ERG recordings in both scotopic and photopic conditions. Moderate levels of Muller cells and microglial reactivity are sided by striking attenuation of staining for RPE tight junctions, suggesting altered integrity of the outer Blood Retina Barrier (BRB). Because of many features resembling slowly progressing photoreceptor degeneration paradigms or early stages of more aggressive forms of RP, the rd9 mouse model can be considered a rare and useful tool to investigate retinal changes associated to a process of photoreceptor death sustained throughout life and to reveal disease biomarkers (e.g., BRB alterations) of human XLRP.
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Affiliation(s)
- Antonio Falasconi
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy.,Sant'Anna School of Advanced Studies, Pisa, Italy
| | - Martina Biagioni
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy
| | - Elena Novelli
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy
| | - Ilaria Piano
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | - Enrica Strettoi
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy
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15
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Abstract
Adeno-associated viral (AAV) gene therapy is becoming an important therapeutic modality, especially for ocular diseases, due to its efficiency of gene delivery and relative lack of pathogenicity. However, AAV sometimes can cause inflammation and toxicity. We explored such effects using injections into the mouse eye. We found a strong correlation of toxicity and inflammation with the use of promoters that were broadly active, or specifically active in the retinal pigment epithelium. AAVs with photoreceptor-specific promoters were found to be nontoxic at all doses tested. These studies reveal that safer vectors can be designed if assays for relevant and specific cell types are developed and tested with a range of vectors with different genomic elements. Adeno-associated viral vectors (AAVs) have become popular for gene therapy, given their many advantages, including their reduced inflammatory profile compared with that of other viruses. However, even in areas of immune privilege such as the eye, AAV vectors are capable of eliciting host-cell responses. To investigate the effects of such responses on several ocular cell types, we tested multiple AAV genome structures and capsid types using subretinal injections in mice. Assays of morphology, inflammation, and physiology were performed. Pathological effects on photoreceptors and the retinal pigment epithelium (RPE) were observed. Müller glia and microglia were activated, and the proinflammatory cytokines TNF-α and IL-1β were up-regulated. There was a strong correlation between cis-regulatory sequences and toxicity. AAVs with any one of three broadly active promoters, or an RPE-specific promoter, were toxic, while AAVs with four different photoreceptor-specific promoters were not toxic at the highest doses tested. There was little correlation between toxicity and transgene, capsid type, preparation method, or cellular contaminants within a preparation. The toxic effect was dose-dependent, with the RPE being more sensitive than photoreceptors. Our results suggest that ocular AAV toxicity is associated with certain AAV cis-regulatory sequences and/or their activity and that retinal damage occurs due to responses by the RPE and/or microglia. By applying multiple, sensitive assays of toxicity, AAV vectors can be designed so that they can be used safely at high dose, potentially providing greater therapeutic efficacy.
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16
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Complex Structural PPT1 Variant Associated with Non-syndromic Canine Retinal Degeneration. G3-GENES GENOMES GENETICS 2019; 9:425-437. [PMID: 30541930 PMCID: PMC6385984 DOI: 10.1534/g3.118.200859] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Rod and cone photoreceptors are specialized retinal neurons that have a fundamental role in visual perception, capturing light and transducing it into a neuronal signal. Aberrant functioning of rod and/or cone photoreceptors can ultimately lead to progressive degeneration and eventually blindness. In man, many rod and rod-cone degenerative diseases are classified as forms of retinitis pigmentosa (RP). Dogs also have a comparable disease grouping termed progressive retinal atrophy (PRA). These diseases are generally due to single gene defects and follow Mendelian inheritance.We collected 51 DNA samples from Miniature Schnauzers affected by PRA (average age of diagnosis ∼3.9 ±1 years), as well as from 56 clinically normal controls of the same breed (average age ∼6.6 ±2.8 years). Pedigree analysis suggested monogenic autosomal recessive inheritance of PRA. GWAS and homozygosity mapping defined a critical interval in the first 4,796,806 bp of CFA15. Whole genome sequencing of two affected cases, a carrier and a control identified two candidate variants within the critical interval. One was an intronic SNV in HIVEP3, and the other was a complex structural variant consisting of the duplication of exon 5 of the PPT1 gene along with a conversion and insertion (named PPT1dci). PPT1dci was confirmed homozygous in a cohort of 22 cases, and 12 more cases were homozygous for the CFA15 haplotype. Additionally, the variant was found homozygous in 6 non-affected dogs of age higher than the average age of onset. The HIVEP3 variant was found heterozygous (n = 4) and homozygous wild-type (n = 1) in cases either homozygous for PPT1dci or for the mapped CFA15 haplotype. We detected the wildtype and three aberrant PPT1 transcripts in isolated white blood cell mRNA extracted from a PRA case homozygous for PPT1dci, and the aberrant transcripts involved inclusion of the duplicated exon 5 and novel exons following the activation of cryptic splice sites. No neurological signs were detected among the dogs homozygous for the PPT1dci variant. Therefore, we propose PPT1dci as causative for a non-syndromic form of PRA (PRAPPT1) that shows incomplete penetrance in Miniature Schnauzers, potentially related to the presence of the wild-type transcript. To our knowledge, this is the first case of isolated retinal degeneration associated with a PPT1 variant.
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17
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Zelinka CP, Sotolongo-Lopez M, Fadool JM. Targeted disruption of the endogenous zebrafish rhodopsin locus as models of rapid rod photoreceptor degeneration. Mol Vis 2018; 24:587-602. [PMID: 30210230 PMCID: PMC6128699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 08/24/2018] [Indexed: 12/05/2022] Open
Abstract
Purpose Retinitis pigmentosa (RP) is a collection of genetic disorders that results in the degeneration of light-sensitive photoreceptor cells, leading to blindness. RP is associated with more than 70 loci that may display dominant or recessive modes of inheritance, but mutations in the gene encoding the visual pigment rhodopsin (RHO) are the most frequent cause. In an effort to develop precise mutations in zebrafish as novel models of photoreceptor degeneration, we describe the generation and germline transmission of a series of novel clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-induced insertion and deletion (indel) mutations in the major zebrafish rho locus, rh1-1. Methods One- or two-cell staged zebrafish embryos were microinjected with in vitro transcribed mRNA encoding Cas9 and a single guide RNA (gRNA). Mutations were detected by restriction fragment length polymorphism (RFLP) and DNA sequence analyses in injected embryos and offspring. Immunolabeling with rod- and cone-specific antibodies was used to test for histological and cellular changes. Results Using gRNAs that targeted highly conserved regions of rh1-1, a series of dominant and recessive alleles were recovered that resulted in the rapid degeneration of rod photoreceptors. No effect on cones was observed. Targeting the 5'-coding sequence of rh1-1 led to the recovery of several indels similar to disease-associated alleles. A frame shift mutation leading to a premature stop codon (T17*) resulted in rod degeneration when brought to homozygosity. Immunoblot and fluorescence labeling with a Rho-specific antibody suggest that this is indeed a null allele, illustrating that the Rho expression is essential for rod survival. Two in-frame mutations were recovered that disrupted the highly conserved N-linked glycosylation consensus sequence at N15. Larvae heterozygous for either of the alleles demonstrated rapid rod degeneration. Targeting of the 3'-coding region of rh1-1 resulted in the recovery of an allele encoding a premature stop codon (S347*) upstream of the conserved VSPA sorting sequence and a second in-frame allele that disrupted the putative phosphorylation site at S339. Both alleles resulted in rod death in a dominant inheritance pattern. Following the loss of the targeting sequence, immunolabeling for Rho was no longer restricted to the rod outer segment, but it was also localized to the plasma membrane. Conclusions The efficiency of CRISPR/Cas9 for gene targeting, coupled with the large number of mutations associated with RP, provided a backdrop for the rapid isolation of novel alleles in zebrafish that phenocopy disease. These novel lines will provide much needed in-vivo models for high throughput screens of compounds or genes that protect from photoreceptor degeneration.
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Affiliation(s)
- Christopher P. Zelinka
- Department of Biological Science, Florida State University, Tallahassee, FL
- Program in Neuroscience, Florida State University, Tallahassee, FL
| | | | - James M. Fadool
- Department of Biological Science, Florida State University, Tallahassee, FL
- Program in Neuroscience, Florida State University, Tallahassee, FL
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18
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Liu L, Yang J, Men K, He Z, Luo M, Qian Z, Wei X, Wei Y. Current Status of Nonviral Vectors for Gene Therapy in China. Hum Gene Ther 2018; 29:110-120. [PMID: 29320893 DOI: 10.1089/hum.2017.226] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Li Liu
- Laboratory for Aging Research and Nanotoxicology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, P.R. China
| | - Jingyun Yang
- Laboratory for Aging Research and Nanotoxicology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, P.R. China
| | - Ke Men
- Laboratory for Aging Research and Nanotoxicology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, P.R. China
| | - Zhiyao He
- Laboratory for Aging Research and Nanotoxicology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, P.R. China
| | - Min Luo
- Laboratory for Aging Research and Nanotoxicology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, P.R. China
| | - Zhiyong Qian
- Laboratory for Aging Research and Nanotoxicology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, P.R. China
| | - Xiawei Wei
- Laboratory for Aging Research and Nanotoxicology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, P.R. China
| | - Yuquan Wei
- Laboratory for Aging Research and Nanotoxicology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, P.R. China
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