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Hashem SA, Georgiou M, Wright G, Fujinami-Yokokawa Y, Laich Y, Varela MD, de Guimaraes TAC, Mahroo OA, Webster AR, Fujinami K, Michaelides M. PDE6A-Associated Retinitis Pigmentosa, Clinical Characteristics, Genetics and Natural History. Ophthalmol Retina 2024:S2468-6530(24)00405-6. [PMID: 39218074 DOI: 10.1016/j.oret.2024.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Revised: 08/09/2024] [Accepted: 08/26/2024] [Indexed: 09/04/2024]
Abstract
PURPOSE To analyze the genetics, clinical characteristics, and natural history of PDE6A-associated retinitis pigmentosa. DESIGN Retrospective, longitudinal, observational cohort study. PARTICIPANTS Patients with molecularly confirmed PDE6A-associated retinal dystrophy in a single tertiary referral center. METHODS Review of medical records and retinal imaging, including fundus autofluorescence (FAF) imaging and spectral-domain optical coherence tomography (SD-OCT). Genetic results were reviewed, and the detected variants were assessed. RESULTS Sixteen patients (32 eyes) were identified and evaluated longitudinally. Genetic analysis identified 14 variants in the PDE6A gene, including 8 novel variants. The mean age (±SD, range) was 34.8 years (± 17.4, 12 - 76) at baseline, with a mean follow-up time of 4.8 years. Best-corrected visual acuity (BCVA) was 0.45 ± 0.45 LogMAR (range 0.0 - 1.6) at baseline and 0.65 ± 0.7 LogMAR (range 0.0 - 2.3) at the last visit. BCVA was similar among eyes in 88% of patients. A hyperautofluorescent ring was observed on FAF in 50% and 44% of the eyes at baseline and follow up visit respectively, with a mean area of 9.7 ± 4.5mm2 at baseline and mean of 8.6 ± 4.8 mm2 at the follow-up visit. Mean horizontal ellipsoid zone width (EZW) at baseline was 1765 ± 1093 μm, which decreased to 1580 ± 1077 μm at follow up. Eighteen eyes exhibited cystoid macular oedema at baseline (56%), and 17 eyes (53%) at follow-up. There were statistically significant changes during the follow-up period in terms of BCVA, hyperautoflouroscent ring area and the EZW. CONCLUSIONS This study highlights the natural history of PDE6A-retinopathy. The majority of the patients in this cohort had mild BCVA loss, and slowly progressive disease, based on FAF and OCT measurements.
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Affiliation(s)
- Shaima Awadh Hashem
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Michalis Georgiou
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
| | - Genevieve Wright
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Yu Fujinami-Yokokawa
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, NHO Tokyo Medical Center, Tokyo, Japan; Department of Health Policy and Management, Keio University School of Medicine, Tokyo, Japan.
| | - Yannik Laich
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Eye Center, Faculty of Medicine, University Freiburg, Germany.
| | - Malena Daich Varela
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Thales A C de Guimaraes
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Omar A Mahroo
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Section of Ophthalmology, King's College London, London, UK; Department of Twin Research and Genetic Epidemiology, King's College London; Eye Department, St Thomas' Hospital, London, UK; Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
| | - Andrew R Webster
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Kaoru Fujinami
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, NHO Tokyo Medical Center, Tokyo, Japan.
| | - Michel Michaelides
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
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Hashem SA, Georgiou M, Fujinami-Yokokawa Y, Laich Y, Daich Varela M, de Guimaraes TAC, Ali N, Mahroo OA, Webster AR, Fujinami K, Michaelides M. Genetics, Clinical Characteristics, and Natural History of PDE6B-Associated Retinal Dystrophy. Am J Ophthalmol 2024; 263:1-10. [PMID: 38364953 DOI: 10.1016/j.ajo.2024.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 02/18/2024]
Abstract
PURPOSE To analyze the clinical characteristics, natural history, and genetics of PDE6B-associated retinal dystrophy. DESIGN Retrospective, observational cohort study. METHODS Review of medical records and retinal imaging, including fundus autofluorescence (FAF) imaging and spectral-domain optical coherence tomography (SD-OCT) of patients with molecularly confirmed PDE6B-associated retinal dystrophy in a single tertiary referral center. Genetic results were reviewed, and the detected variants were assessed. RESULTS Forty patients (80 eyes) were identified and evaluated longitudinally. The mean age (±SD, range) was 42.1 years (± 19.0, 10-86) at baseline, with a mean follow-up time of 5.2 years. Twenty-nine (72.5%) and 27 (67.5%) patients had no or mild visual acuity impairment at baseline and last visit, respectively. Best-corrected visual acuity (BCVA) was 0.56 ± 0.72 LogMAR (range -0.12 to 2.80) at baseline and 0.63 ± 0.73 LogMAR (range 0.0-2.80) at the last visit. BCVA was symmetrical in 87.5% of patients. A hyperautofluorescent ring was observed on FAF in 48 and 46 eyes at baseline and follow-up visit, respectively, with a mean area of 7.11 ± 4.13 mm2 at baseline and mean of 6.13 ± 3.62 mm2 at the follow-up visit. Mean horizontal ellipsoid zone width at baseline was 1946.1 ± 917.2 µm, which decreased to 1763.9 ± 827.9 µm at follow-up. Forty-four eyes had cystoid macular edema at baseline (55%), and 41 eyes (51.3%) at follow-up. There were statistically significant changes during the follow-up period in terms of BCVA and the ellipsoid zone width. Genetic analysis identified 43 variants in the PDE6B gene, including 16 novel variants. CONCLUSIONS This study details the natural history of PDE6B-retinopathy in the largest cohort to date. Most patients had mild to no BCVA loss, with slowly progressive disease, based on FAF and OCT metrics. There is a high degree of disease symmetry and a wide window for intervention.
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Affiliation(s)
- Shaima Awadh Hashem
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom
| | - Michalis Georgiou
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; Jones Eye Institute, University of Arkansas for Medical Sciences (M.G.), Little Rock, Arkansas, USA
| | - Yu Fujinami-Yokokawa
- UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research (Y.F.Y.), National Institute of Sensory Organs, NHONHO Tokyo Medical Center, Tokyo, Japan; Department of Health Policy and Management (Y.F.Y.), Keio University School of Medicine, Tokyo, Japan
| | - Yannik Laich
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; Eye Center, Faculty of Medicine, University Freiburg (Y.L.), Germany
| | - Malena Daich Varela
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom
| | - Thales A C de Guimaraes
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom
| | - Naser Ali
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom
| | - Omar A Mahroo
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; Section of Ophthalmology, King's College London, St Thomas' Hospital Campus (O.A.M.), London, United Kingdom; Department of Physiology, Development and Neuroscience, University of Cambridge (O.A.M.), Cambridge, United Kingdom
| | - Andrew R Webster
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom
| | - Kaoru Fujinami
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research (Y.F.Y.), National Institute of Sensory Organs, NHONHO Tokyo Medical Center, Tokyo, Japan
| | - Michel Michaelides
- From the Moorfields Eye Hospital (S.A.H., M.G., Y.L., M.D.V., T.A.C.d.G., N.A., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (S.A.H., M.G., Y.F.Y., Y.L., M.D.V., T.A.C.d.G., O.A.M., A.R.W., K.F., M.M.), London, United Kingdom.
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Aziz N, Ullah M, Rashid A, Hussain Z, Shah K, Awan A, Khan M, Ullah I, Rehman AU. A novel homozygous missense substitution p.Thr313Ile in the PDE6B gene underlies autosomal recessive retinitis pigmentosa in a consanguineous Pakistani family. BMC Ophthalmol 2023; 23:116. [PMID: 36959549 PMCID: PMC10035148 DOI: 10.1186/s12886-023-02845-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 03/07/2023] [Indexed: 03/25/2023] Open
Abstract
BACKGROUND Retinitis pigmentosa (RP) is one of the most frequent hereditary retinal diseases that often starts with night blindness and eventually leads to legal blindness. Our study aimed to identify the underlying genetic cause of autosomal recessive retinitis pigmentosa (arRP) in a consanguineous Pakistani family. METHODS Following a detailed ophthalmological examination of the patients by an ophthalmologist, whole-exome sequencing was performed on the proband's DNA to delineate the genetic cause of RP in the family. In-depth computational methods, in-silico analysis, and familial co-segregation study were performed for variant detection and validation. RESULTS We studied an inbred Pakistani family with two siblings affected by retinitis pigmentosa. The proband, a 32 years old female, was clinically diagnosed with RP at the age of 6 years. A classical night blindness symptom was reported in the proband since her early childhood. OCT report showed a major reduction in the outer nuclear layer and the ellipsoid zone width, leading to the progression of the disease. Exome sequencing revealed a novel homozygous missense mutation (c.938C > T;p.Thr313Ile) in exon 12 of the PDE6B gene. The mutation p.Thr313Ile co-segregated with RP phenotype in the family. The altered residue (p.Thr313) was super conserved evolutionarily across different vertebrate species, and all available in silico tools classified the mutation as highly pathogenic. CONCLUSION We present a novel homozygous pathogenic mutation in the PDE6B gene as the underlying cause of arRP in a consanguineous Pakistani family. Our findings highlight the importance of missense mutations in the PDE6B gene and expand the known mutational repertoire of PDE6B-related RP.
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Affiliation(s)
- Nobia Aziz
- Department of Biotechnology and Genetic Engineering, Faculty of Biological and Health Sciences, Hazara University, Mansehra, Pakistan
| | - Mukhtar Ullah
- Institute of Molecular and Clinical Ophthalmology Basel, University of Basel, Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Abdur Rashid
- Department of Higher Education Archives and Libraries Peshawar, Government of Khyber Pakhtunkhwa, Peshawar, Pakistan
| | - Zubair Hussain
- Department of Biotechnology, COMSATS University Islamabad, Abbottabad Campus, Abbottabad, Pakistan
| | - Khadim Shah
- Department of Biotechnology, COMSATS University Islamabad, Abbottabad Campus, Abbottabad, Pakistan
| | - Azeem Awan
- LRBT Secondary Eye Hospital, Reerah Galla, Balakot Road, Mansehra, Khyber Pakhtunkhwa, Pakistan
| | - Muhammad Khan
- Department of Biotechnology and Genetic Engineering, Faculty of Biological and Health Sciences, Hazara University, Mansehra, Pakistan
| | - Inam Ullah
- Department of Biotechnology and Genetic Engineering, Faculty of Biological and Health Sciences, Hazara University, Mansehra, Pakistan
| | - Atta Ur Rehman
- Department of Zoology, Faculty of Biological and Health Sciences, Hazara University, Mansehra, Pakistan.
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Robles Bocanegra A, Tato J, Molina Thurin LJ, Izquierdo N, Oliver AL. Pseudodominant Inheritance of Retinitis Pigmentosa Due to Mutations in the Phosphodiesterase 6B Gene: A Case Report. Cureus 2023; 15:e34933. [PMID: 36938204 PMCID: PMC10016385 DOI: 10.7759/cureus.34933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2023] [Indexed: 02/16/2023] Open
Abstract
Mutations in the phosphodiesterase 6B (PDE6B) gene are a rare cause of autosomal recessive retinitis pigmentosa (arRP). We report on a non-consanguineous family with a pseudodominant inheritance of RP due to PDE6B mutations. We conducted a chart review of four members of a Puerto Rican family who underwent a comprehensive ophthalmic evaluation by at least one of the authors. The mutational screening was done using a genotyping microarray provided by Invitae Corporation, using next-generation sequencing (NGS) technology. Genomic DNA obtained from saliva samples is enriched for targeted regions using a hybridization-based protocol and sequenced using Illumina technology. A descriptive analysis was done. Patient 1A had a normal ophthalmic examination and a heterozygous pathogenic variant in the PDE6B gene c.1540del PLeu514Trpfs*61. Patients 1B, 2A, and 2B had mid-peripheral retinitis pigmentosa, concentric visual field ring scotomata in both eyes (OU), extinguished electroretinogram (ERG), and homozygous pathogenic variants in the PDE6B gene c.1540del PLeu514Trpfs*61. Even though mutations in the PDE6B gene usually lead to arRP, they may be inherited in a pseudodominant pattern in geographically isolated populations. Genotyping studies in patients with RP are warranted to classify inheritance mode correctly.
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Affiliation(s)
| | - Javier Tato
- Ophthalmology, Ponce Health Sciences University, Ponce, PRI
| | | | - Natalio Izquierdo
- Surgery, School of Medicine, Medical Sciences Campus, University of Puerto Rico, San Juan, PRI
| | - Armando L Oliver
- Ophthalmology, School of Medicine, Medical Sciences Campus, University of Puerto Rico, San Juan, USA
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Depleted Calcium Stores and Increased Calcium Entry in Rod Photoreceptors of the Cacna2d4 Mouse Model of Cone-Rod Dystrophy RCD4. Int J Mol Sci 2022; 23:ijms232113080. [DOI: 10.3390/ijms232113080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/17/2022] [Accepted: 10/21/2022] [Indexed: 11/16/2022] Open
Abstract
Unidentified pathogenetic mechanisms and genetic and clinical heterogeneity represent critical factors hindering the development of treatments for inherited retinal dystrophies. Frameshift mutations in Cacna2d4, which codes for an accessory subunit of voltage-gated calcium channels (VGCC), cause cone-rod dystrophy RCD4 in patients, but the underlying mechanisms remain unknown. To define its pathogenetic mechanisms, we investigated the impact of a Cacna2d4 frameshift mutation on the electrophysiological profile and calcium handling of mouse rod photoreceptors by patch-clamp recordings and calcium imaging, respectively. In mutant (MUT) rods, the dysregulation of calcium handling extends beyond the reduction in calcium entry through VGCC and surprisingly involves internal calcium stores’ depletion and upregulation of calcium entry via non-selective cationic channels (CSC). The similar dependence of CSC on basal calcium levels in WT and MUT rods suggests that the primary defect in MUT rods lies in defective calcium stores. Calcium stores’ depletion, leading to upregulated calcium and sodium influx via CSC, represents a novel and, so far, unsuspected consequence of the Cacna2d4 mutation. Blocking CSC may provide a novel strategy to counteract the well-known pathogenetic mechanisms involved in rod demise, such as the reticulum stress response and calcium and sodium overload due to store depletion.
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Li Y, Li R, Dai H, Li G. Novel variants in PDE6A and PDE6B genes and its phenotypes in patients with retinitis pigmentosa in Chinese families. BMC Ophthalmol 2022; 22:27. [PMID: 35033039 PMCID: PMC8761266 DOI: 10.1186/s12886-021-02242-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 12/30/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Retinitis pigmentosa (RP) is a genetically heterogeneous disease with 89 causative genes identified to date. However, only approximately 60% of RP cases genetically solved to date, predicating that many novel disease-causing variants are yet to be identified. The purpose of this study is to identify novel variants in PDE6A and PDE6B genes and present its phenotypes in patients with retinitis pigmentosa in Chinese families. METHODS Five retinitis pigmentosa patients with PDE6A variants and three with PDE6B variants were identified through a hereditary eye disease enrichment panel (HEDEP), all patients' medical and ophthalmic histories were collected, and ophthalmological examinations were performed, followed by an analysis of the possible causative variants. Sanger sequencing was used to verify the variants. RESULTS We identified 20 variants in eight patients: 16 of them were identified in either PDE6A or PDE6B in a compound heterozygous state. Additional four heterozygous variants were identified in the genes ADGRA3, CA4, OPTN, RHO. Two novel genetic changes in PDE6A were identified (c.1246G > A and c.1747 T > A), three novel genetic changes in PDE6B were identified (c.401 T > C, c.2293G > C and c.1610-1612del), out of the novel identified variants one was most probably non-pathogenic (c.2293G > C), all other novel variants are pathogenic. Additional variant was identified in CA4 and RHO, which can cause ADRP (c.243G > A, c.688G > A). In addition, a novel variant in ADGRA3 was identified (c.921-1G > A). CONCLUSIONS This study reveals novel and known variants in PDE6A and PDE6B genes in Chinese families with autosomal recessive RP, and expands the clinical and genetic findings of photoreceptor-specific enzyme deficiencies.
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Affiliation(s)
- Yuyu Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, 100730 People’s Republic of China
| | - Ruyi Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, 100730 People’s Republic of China
| | - Hehua Dai
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, 100730 People’s Republic of China
| | - Genlin Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, 100730 People’s Republic of China
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7
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Marconi S, Stout JT. PDE6B Mutation-associated Inherited Retinal Disease. Int Ophthalmol Clin 2021; 61:133-142. [PMID: 34584050 DOI: 10.1097/iio.0000000000000367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Zhang L, Chen C, Fu J, Lilley B, Berlinicke C, Hansen B, Ding D, Wang G, Wang T, Shou D, Ye Y, Mulligan T, Emmerich K, Saxena MT, Hall KR, Sharrock AV, Brandon C, Park H, Kam TI, Dawson VL, Dawson TM, Shim JS, Hanes J, Ji H, Liu JO, Qian J, Ackerley DF, Rohrer B, Zack DJ, Mumm JS. Large-scale phenotypic drug screen identifies neuroprotectants in zebrafish and mouse models of retinitis pigmentosa. eLife 2021; 10:e57245. [PMID: 34184634 PMCID: PMC8425951 DOI: 10.7554/elife.57245] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/28/2021] [Indexed: 11/25/2022] Open
Abstract
Retinitis pigmentosa (RP) and associated inherited retinal diseases (IRDs) are caused by rod photoreceptor degeneration, necessitating therapeutics promoting rod photoreceptor survival. To address this, we tested compounds for neuroprotective effects in multiple zebrafish and mouse RP models, reasoning drugs effective across species and/or independent of disease mutation may translate better clinically. We first performed a large-scale phenotypic drug screen for compounds promoting rod cell survival in a larval zebrafish model of inducible RP. We tested 2934 compounds, mostly human-approved drugs, across six concentrations, resulting in 113 compounds being identified as hits. Secondary tests of 42 high-priority hits confirmed eleven lead candidates. Leads were then evaluated in a series of mouse RP models in an effort to identify compounds effective across species and RP models, that is, potential pan-disease therapeutics. Nine of 11 leads exhibited neuroprotective effects in mouse primary photoreceptor cultures, and three promoted photoreceptor survival in mouse rd1 retinal explants. Both shared and complementary mechanisms of action were implicated across leads. Shared target tests implicated parp1-dependent cell death in our zebrafish RP model. Complementation tests revealed enhanced and additive/synergistic neuroprotective effects of paired drug combinations in mouse photoreceptor cultures and zebrafish, respectively. These results highlight the value of cross-species/multi-model phenotypic drug discovery and suggest combinatorial drug therapies may provide enhanced therapeutic benefits for RP patients.
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Affiliation(s)
- Liyun Zhang
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Conan Chen
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Jie Fu
- The Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Brendan Lilley
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Cynthia Berlinicke
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Baranda Hansen
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Ding Ding
- Department of Biostatistics, Johns Hopkins UniversityBaltimoreUnited States
| | - Guohua Wang
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Tao Wang
- The Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
- School of Chemistry, Xuzhou College of Industrial TechnologyXuzhouChina
- College of Light Industry and Food Engineering, Nanjing Forestry UniversityNanjingChina
| | - Daniel Shou
- The Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Ying Ye
- The Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Timothy Mulligan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Kevin Emmerich
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
- Department of Genetic Medicine, Johns Hopkins UniversityBaltimoreUnited States
| | - Meera T Saxena
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Kelsi R Hall
- School of Biological Sciences, Victoria University of WellingtonWellingtonNew Zealand
| | - Abigail V Sharrock
- Department of Biostatistics, Johns Hopkins UniversityBaltimoreUnited States
- School of Biological Sciences, Victoria University of WellingtonWellingtonNew Zealand
| | - Carlene Brandon
- Department of Ophthalmology, Medical University of South CarolinaCharlestonUnited States
| | - Hyejin Park
- Department of Neurology, Johns Hopkins UniversityBaltimoreUnited States
| | - Tae-In Kam
- Department of Neurology, Johns Hopkins UniversityBaltimoreUnited States
- Institute for Cell Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Valina L Dawson
- Department of Neurology, Johns Hopkins UniversityBaltimoreUnited States
- Institute for Cell Engineering, Johns Hopkins UniversityBaltimoreUnited States
- Department of Pharmacology and Molecular Sciences, Johns Hopkins UniversityBaltimoreUnited States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
| | - Ted M Dawson
- Department of Neurology, Johns Hopkins UniversityBaltimoreUnited States
- Institute for Cell Engineering, Johns Hopkins UniversityBaltimoreUnited States
- Department of Pharmacology and Molecular Sciences, Johns Hopkins UniversityBaltimoreUnited States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
| | - Joong Sup Shim
- Faculty of Health Sciences, University of Macau, TaipaMacauChina
| | - Justin Hanes
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
- The Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Hongkai Ji
- Department of Biostatistics, Johns Hopkins UniversityBaltimoreUnited States
| | - Jun O Liu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins UniversityBaltimoreUnited States
- Department of Oncology, Johns Hopkins UniversityBaltimoreUnited States
| | - Jiang Qian
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - David F Ackerley
- School of Biological Sciences, Victoria University of WellingtonWellingtonNew Zealand
| | - Baerbel Rohrer
- Department of Ophthalmology, Medical University of South CarolinaCharlestonUnited States
| | - Donald J Zack
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
- The Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
- Department of Genetic Medicine, Johns Hopkins UniversityBaltimoreUnited States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
- Department of Molecular Biology and Genetics, Johns Hopkins UniversityBaltimoreUnited States
| | - Jeff S Mumm
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
- The Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins UniversityBaltimoreUnited States
- Department of Genetic Medicine, Johns Hopkins UniversityBaltimoreUnited States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
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9
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Clinical Phenotype of PDE6B-Associated Retinitis Pigmentosa. Int J Mol Sci 2021; 22:ijms22052374. [PMID: 33673512 PMCID: PMC7956818 DOI: 10.3390/ijms22052374] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/17/2021] [Accepted: 02/21/2021] [Indexed: 11/25/2022] Open
Abstract
In this retrospective, longitudinal, observational cohort study, we investigated the phenotypic and genotypic features of retinitis pigmentosa associated with variants in the PDE6B gene. Patients underwent clinical examination and genetic testing at a single tertiary referral center, including best-corrected visual acuity (BCVA), kinetic visual field (VF), full-field electroretinography, full-field stimulus threshold, spectral domain optical coherence tomography, and fundus autofluorescence imaging. The genetic testing comprised candidate gene sequencing, inherited retinal disease gene panel sequencing, whole-genome sequencing, and testing for familial variants by Sanger sequencing. Twenty-four patients with mutations in PDE6B from 21 families were included in the study (mean age at the first visit: 32.1 ± 13.5 years). The majority of variants were putative splicing defects (8/23) and missense (7/23) mutations. Seventy-nine percent (38/48) of eyes had no visual acuity impairment at the first visit. Visual acuity impairment was mild in 4% (2/48), moderate in 13% (6/48), and severe in 4% (2/48). BCVA was symmetrical in the right and left eyes. The kinetic VF measurements were highly symmetrical in the right and left eyes, as was the horizontal ellipsoid zone (EZ) width. Regarding the genetic findings, 43% of the PDE6B variants found in our patients were novel. Thus, this study contributed substantially to the PDE6B mutation spectrum. The visual acuity impairment was mild in 83% of eyes, providing a window of opportunity for investigational new drugs. The EZ width was reduced in all patients and was highly symmetric between the eyes, making it a promising outcome measure. We expect these findings to have implications on the design of future PDE6B-related retinitis pigmentosa (RP) clinical trials.
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10
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Zhang J, Kuvelkar R, Wu P, Egan RW, Billah MM, Wang P. Differential inhibitor sensitivity between human recombinant and native photoreceptor cGMP-phosphodiesterases (PDE6s). Biochem Pharmacol 2004; 68:867-73. [PMID: 15294449 DOI: 10.1016/j.bcp.2004.05.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Accepted: 05/11/2004] [Indexed: 10/26/2022]
Abstract
Human photoreceptor cGMP-phosphodiesterases (PDE6s) are important reagents in PDE inhibitor discovery. However, recombinant human PDE6s have not been expressed, and isolation of native human PDE6s is highly difficult. In this study, the catalytic subunit(s) of human rod and cone PDE6s (PDE6alphabeta and PDE6alpha', respectively) were co-expressed or expressed separately as catalytically active enzymes. Sildenafil inhibited both the recombinant PDE6s in a dose-dependent manner with Ki values of 94 and 98 nM, respectively. These Ki values were four-fold higher than that (25 nM) of a human native PDE6 preparation. Similarly, 3-isobutyl-1-methylxanthine (IBMX)'s Ki values for the recombinant PDE6s were five- to eight-fold higher than that of the native enzyme. However, E4021 and zaprinast exhibited much (30-80-fold) lower potencies for the recombinant PDE6s than for the native enzyme. Additional PDE5 inhibitors representing other structural classes and possessing different selectivity against native PDE6 also showed different potencies against the recombinant and native PDE6s. In particular, one class of xanthine analogues exhibited significantly (5-15-fold) higher potencies for the recombinant PDE6s than for the native enzyme. Our data demonstrates that the recombinant and native PDE6s exhibit differential sensitivity to inhibitors, and cautions the use of recombinant catalytic subunits of PDE6 in drug discovery or in structural/functional studies.
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Affiliation(s)
- Ji Zhang
- Allergy Department, Schering-Plough Research Institute, Kenilworth, NJ 07033, USA
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11
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Xu S, Ladak R, Swanson DA, Soltyk A, Sun H, Ploder L, Vidgen D, Duncan AM, Garami E, Valle D, McInnes RR. PHR1 encodes an abundant, pleckstrin homology domain-containing integral membrane protein in the photoreceptor outer segments. J Biol Chem 1999; 274:35676-85. [PMID: 10585447 DOI: 10.1074/jbc.274.50.35676] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We cloned human and murine cDNAs of a gene (designated PHR1), expressed preferentially in retina and brain. In both species, PHR1 utilizes two promoters and alternative splicing to produce four PHR1 transcripts, encoding isoforms of 243, 224, 208, and 189 amino acids, each with a pleckstrin homology domain at their N terminus and a transmembrane domain at their C terminus. Transcript 1 originates from a 5'-photoreceptor-specific promoter with at least three Crx elements ((C/T)TAATCC). Transcript 2 originates from the same promoter but lacks exon 7, which encodes 35 amino acids immediately C-terminal to the pleckstrin homology domain. Transcripts 3 and 4 originate from an internal promoter in intron 2 and either include or lack exon 7, respectively. In situ hybridization shows that PHR1 is highly expressed in photoreceptors, with lower expression in retinal ganglion cells. Immunohistochemistry localizes the PHR1 protein to photoreceptor outer segments where chemical extraction studies confirm it is an integral membrane protein. Using a series of PHR1 glutathione S-transferase fusion proteins to perform in vitro binding assays, we found PHR1 binds transducin betagamma subunits but not inositol phosphates. This activity and subcellular location suggests that PHR1 may function as a previously unrecognized modulator of the phototransduction pathway.
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Affiliation(s)
- S Xu
- Predoctoral Training Program in Human Genetics, Department of Pediatrics, Baltimore, Maryland 21205, USA
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12
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Conti M, Jin SL. The molecular biology of cyclic nucleotide phosphodiesterases. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1999; 63:1-38. [PMID: 10506827 DOI: 10.1016/s0079-6603(08)60718-7] [Citation(s) in RCA: 352] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent progress in the field of cyclic nucleotides has shown that a large array of closely related proteins is involved in each step of the signal transduction cascade. Nine families of adenylyl cyclases catalyze the synthesis of the second messenger cAMP, and protein kinases A, the intracellular effectors of cAMP, are composed of four regulatory and three catalytic subunits. A comparable heterogeneity has been discovered for the enzymes involved in the inactivation of cyclic nucleotide signaling. In mammals, 19 different genes encode the cyclic nucleotide phosphodiesterases (PDEs), the enzymes that hydrolyze and inactivate cAMP and cGMP. This is only an initial level of complexity, because each PDE gene contains several distinct transcriptional units that give rise to proteins with subtle structural differences, bringing the number of the PDE proteins close to 50. The molecular biology of PDEs in Drosophila and Dictyostelium has shed some light on the role of PDE diversity in signaling and development. However, much needs to be done to understand the exact function of these enzymes, particularly during mammalian development and cell differentiation. With the identification and mapping of regulatory and targeting domains of the PDEs, modularity of the PDE structure is becoming an established tenet in the PDE field. The use of different transcriptional units and exon splicing of a single PDE gene generates proteins with different regulatory domains joined to a common catalytic domain, therefore expanding the array of isoforms with subtle differences in properties and sensitivities to different signals. The physiological context in which these different isoforms function is still largely unknown and undoubtedly will be a major area of expansion in the years to come.
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Affiliation(s)
- M Conti
- Department of Gynecology and Obstetrics, Stanford University School of Medicine, California 94305, USA
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13
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Katayama M, Ohmori M. Isolation and characterization of multiple adenylate cyclase genes from the cyanobacterium Anabaena sp. strain PCC 7120. J Bacteriol 1997; 179:3588-93. [PMID: 9171404 PMCID: PMC179152 DOI: 10.1128/jb.179.11.3588-3593.1997] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Adenylate cyclase genes, designated cyaA, cyaB1, cyaB2, cyaC, and cyaD, were isolated from the filamentous cyanobacterium Anabaena sp. strain PCC 7120 by complementation of a strain of Escherichia coli defective for the presence of cya. These genes encoded polypeptides consisting of 735, 859, 860, 1,155, and 546 amino acid residues, respectively. Deduced amino acid sequences of the regions near the C-terminal ends of these cya genes were similar to those of catalytic domains of eukaryotic adenylate cyclases. The remaining part of each cya gene towards its N-terminal end showed a characteristic structure. CyaA had two putative membrane-spanning regions. Both CyaB1 and CyaB2 had regions that were very similar to the cyclic GMP (cGMP)-binding domain of cGMP-stimulated cGMP phosphodiesterase. CyaC consisted of four distinct domains forming sequentially from the N terminus: a response regulator-like domain, a histidine kinase-like domain, a response regulator-like domain, and the catalytic domain of adenylate cyclase. CyaD contained the forkhead-associated domain in its N-terminal region. Expression of these genes was examined by reverse transcription-PCR. The transcript of cyaC was shown to be predominant in this cyanobacterium. The cellular cyclic AMP level in the disruptant of the cyaC mutant was much lower than that in the wild type.
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Affiliation(s)
- M Katayama
- Department of Life Science, Graduate School of Arts and Sciences, University of Tokyo, Meguro, Japan
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14
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Feshchenko EA, Andreeva SG, Suslova VA, Smirnova EV, Zagranichny VE, Lipkin VM. Human cone-specific cGMP phosphodiesterase alpha' subunit: complete cDNA sequence and gene arrangement. FEBS Lett 1996; 381:149-52. [PMID: 8641425 DOI: 10.1016/0014-5793(96)00104-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Four independent phage clones containing the fragments of cone-specific cGMP phosphodiesterase (PDE) alpha' subunit (PDE-alpha') cDNA were isolated from the human cDNA library. The screening of the genomic library resulted in isolation of four independent phage clones with the fragments of human cone PDEalpha' gene including 5'-flanking region and exons ranged from 1 to 14 (overall 32 kilobases). Structural studies of the clones made it possible to establish the complete human cone PDEalpha' cDNA structure (3455 base pairs). The encoding polypeptide consists of 858 amino acid residues with a calculated molecular mass of 99169 Da. The deduced amino acid sequence displays high homology to the earlier analyzed catalytic alpha, beta and alpha' subunits of bovine, human, chicken and mouse photoreceptor PDEs.
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Affiliation(s)
- E A Feshchenko
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow
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15
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Gal A, Orth U, Baehr W, Schwinger E, Rosenberg T. Heterozygous missense mutation in the rod cGMP phosphodiesterase beta-subunit gene in autosomal dominant stationary night blindness. Nat Genet 1994; 7:64-8. [PMID: 8075643 DOI: 10.1038/ng0594-64] [Citation(s) in RCA: 164] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The locus for autosomal dominant congenital stationary night blindness (adCSNB) has recently been assigned to distal chromosome 4p by linkage analysis in a large Danish family. Within the candidate gene encoding the beta-subunit of rod photoreceptor cGMP-specific phosphodiesterase (beta PDE), we have identified a heterozygous C to A transversion in exon 4, predicting a His258Asp change in the polypeptide. We found a perfect cosegregation (Zmax = 22.6 at theta = 0.00) of this mutation with the disease phenotype suggesting that this missense mutation is responsible for the disease in this pedigree. Homozygous nonsense mutations in the beta PDE gene have been found recently in patients with autosomal recessive retinitis pigmentosa, a common hereditary photoreceptor dystrophy.
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Affiliation(s)
- A Gal
- Institut für Humangenetik, Medizinische Universität, Lübeck, Germany
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