1
|
Hong JD, Salom D, Choi EH, Du SW, Tworak A, Smidak R, Gao F, Solano YJ, Zhang J, Kiser PD, Palczewski K. Retinylidene chromophore hydrolysis from mammalian visual and non-visual opsins. J Biol Chem 2024; 300:105678. [PMID: 38272218 PMCID: PMC10877631 DOI: 10.1016/j.jbc.2024.105678] [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: 11/30/2023] [Revised: 01/06/2024] [Accepted: 01/13/2024] [Indexed: 01/27/2024] Open
Abstract
Rhodopsin (Rho) and cone opsins are essential for detection of light. They respond via photoisomerization, converting their Schiff-base-adducted 11-cis-retinylidene chromophores to the all-trans configuration, eliciting conformational changes to activate opsin signaling. Subsequent Schiff-base hydrolysis releases all-trans-retinal, initiating two important cycles that maintain continuous vision-the Rho photocycle and visual cycle pathway. Schiff-base hydrolysis has been thoroughly studied with photoactivated Rho but not with cone opsins. Using established methodology, we directly measured the formation of Schiff-base between retinal chromophores with mammalian visual and nonvisual opsins of the eye. Next, we determined the rate of light-induced chromophore hydrolysis. We found that retinal hydrolysis from photoactivated cone opsins was markedly faster than from photoactivated Rho. Bovine retinal G protein-coupled receptor (bRGR) displayed rapid hydrolysis of its 11-cis-retinylidene photoproduct to quickly supply 11-cis-retinal and re-bind all-trans-retinal. Hydrolysis within bRGR in native retinal pigment epithelium microsomal membranes was >6-times faster than that of bRGR purified in detergent micelles. N-terminal-targeted antibodies significantly slowed bRGR hydrolysis, while C-terminal antibodies had no effect. Our study highlights the much faster photocycle of cone opsins relative to Rho and the crucial role of RGR in chromophore recycling in daylight. By contrast, in our experimental conditions, bovine peropsin did not form pigment in the presence of all-trans-retinal nor with any mono-cis retinal isomers, leaving uncertain the role of this opsin as a light sensor.
Collapse
Affiliation(s)
- John D Hong
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Chemistry, University of California Irvine, Irvine, California, USA
| | - David Salom
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA.
| | - Elliot H Choi
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Samuel W Du
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Physiology and Biophysics, University of California Irvine, Irvine, California, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Roman Smidak
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Fangyuan Gao
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Yasmeen J Solano
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Physiology and Biophysics, University of California Irvine, Irvine, California, USA
| | - Jianye Zhang
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Philip D Kiser
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Physiology and Biophysics, University of California Irvine, Irvine, California, USA; Department of Clinical Pharmacy Practice, University of California Irvine, Irvine, California, USA; Research Service, VA Long Beach Healthcare System, Long Beach, California, USA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Chemistry, University of California Irvine, Irvine, California, USA; Department of Physiology and Biophysics, University of California Irvine, Irvine, California, USA; Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, USA.
| |
Collapse
|
2
|
In vivo base editing rescues cone photoreceptors in a mouse model of early-onset inherited retinal degeneration. Nat Commun 2022; 13:1830. [PMID: 35383196 PMCID: PMC8983734 DOI: 10.1038/s41467-022-29490-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 03/17/2022] [Indexed: 12/17/2022] Open
Abstract
Leber congenital amaurosis (LCA) is the most common cause of inherited retinal degeneration in children. LCA patients with RPE65 mutations show accelerated cone photoreceptor dysfunction and death, resulting in early visual impairment. It is therefore crucial to develop a robust therapy that not only compensates for lost RPE65 function but also protects photoreceptors from further degeneration. Here, we show that in vivo correction of an Rpe65 mutation by adenine base editor (ABE) prolongs the survival of cones in an LCA mouse model. In vitro screening of ABEs and sgRNAs enables the identification of a variant that enhances in vivo correction efficiency. Subretinal delivery of ABE and sgRNA corrects up to 40% of Rpe65 transcripts, restores cone-mediated visual function, and preserves cones in LCA mice. Single-cell RNA-seq reveals upregulation of genes associated with cone phototransduction and survival. Our findings demonstrate base editing as a potential gene therapy that confers long-lasting retinal protection. Leber congenital amaurosis is caused by mutations in RPE65 and leads to retinal degeneration in children. Here, the authors show that in vivo base editing can prolong the survival of cone photoreceptors and rescue their function in a mouse model of the disease.
Collapse
|
3
|
Koster C, van den Hurk KT, Lewallen CF, Talib M, ten Brink JB, Boon CJF, Bergen AA. The Lrat -/- Rat: CRISPR/Cas9 Construction and Phenotyping of a New Animal Model for Retinitis Pigmentosa. Int J Mol Sci 2021; 22:ijms22137234. [PMID: 34281288 PMCID: PMC8267968 DOI: 10.3390/ijms22137234] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/27/2021] [Accepted: 06/29/2021] [Indexed: 11/16/2022] Open
Abstract
PURPOSE We developed and phenotyped a pigmented knockout rat model for lecithin retinol acyltransferase (LRAT) using CRISPR/Cas9. The introduced mutation (c.12delA) is based on a patient group harboring a homologous homozygous frameshift mutation in the LRAT gene (c.12delC), causing a dysfunctional visual (retinoid) cycle. METHODS The introduced mutation was confirmed by DNA and RNA sequencing. The expression of Lrat was determined on both the RNA and protein level in wildtype and knockout animals using RT-PCR and immunohistochemistry. The retinal structure and function, as well as the visual behavior of the Lrat-/- and control rats, were characterized using scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), electroretinography (ERG) and vision-based behavioral assays. RESULTS Wildtype animals had high Lrat mRNA expression in multiple tissues, including the eye and liver. In contrast, hardly any expression was detected in Lrat-/- animals. LRAT protein was abundantly present in wildtype animals and absent in Lrat-/- animals. Lrat-/- animals showed progressively reduced ERG potentials compared to wildtype controls from two weeks of age onwards. Vison-based behavioral assays confirmed reduced vision. Structural abnormalities, such as overall retinal thinning, were observed in Lrat-/- animals. The retinal thickness in knockout rats was decreased to roughly 80% by four months of age. No functional or structural differences were observed between wildtype and heterozygote animals. CONCLUSIONS Our Lrat-/- rat is a new animal model for retinal dystrophy, especially for the LRAT-subtype of early-onset retinal dystrophies. This model has advantages over the existing mouse models and the RCS rat strain and can be used for translational studies of retinal dystrophies.
Collapse
Affiliation(s)
- Céline Koster
- Department of Human Genetics Amsterdam, Section of Ophthalmogenetics, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands; (C.K.); (K.T.v.d.H.); (J.B.t.B.)
| | - Koen T. van den Hurk
- Department of Human Genetics Amsterdam, Section of Ophthalmogenetics, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands; (C.K.); (K.T.v.d.H.); (J.B.t.B.)
| | - Colby F. Lewallen
- Georgia Institute of Technology, G.W. Woodruff School of Mechanical Engineering, Atlanta, GA 30313, USA;
| | - Mays Talib
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands; (M.T.); (C.J.F.B.)
| | - Jacoline B. ten Brink
- Department of Human Genetics Amsterdam, Section of Ophthalmogenetics, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands; (C.K.); (K.T.v.d.H.); (J.B.t.B.)
| | - Camiel J. F. Boon
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands; (M.T.); (C.J.F.B.)
- Department of Ophthalmology, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands
| | - Arthur A. Bergen
- Department of Human Genetics Amsterdam, Section of Ophthalmogenetics, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands; (C.K.); (K.T.v.d.H.); (J.B.t.B.)
- Department of Ophthalmology, Amsterdam University Medical Centers (AUMC), University of Amsterdam (UvA), Location Meibergdreef, 1105 AZ Amsterdam, The Netherlands
- The Netherlands Institute for Neuroscience (NIN-KNAW), 1105 BA Amsterdam, The Netherlands
- Correspondence:
| |
Collapse
|
4
|
Ramkumar S, Moon J, Golczak M, von Lintig J. LRAT coordinates the negative-feedback regulation of intestinal retinoid biosynthesis from β-carotene. J Lipid Res 2021; 62:100055. [PMID: 33631212 PMCID: PMC8010212 DOI: 10.1016/j.jlr.2021.100055] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/02/2021] [Accepted: 02/17/2021] [Indexed: 11/23/2022] Open
Abstract
There is increasing recognition that dietary lipids can affect the expression of genes encoding their metabolizing enzymes, transporters, and binding proteins. This mechanism plays a pivotal role in controlling tissue homeostasis of these compounds and avoiding diseases. The regulation of retinoid biosynthesis from β-carotene (BC) is a classic example for such an interaction. The intestine-specific homeodomain transcription factor (ISX) controls the activity of the vitamin A-forming enzyme β-carotene oxygenase-1 in intestinal enterocytes in response to increasing concentration of the vitamin A metabolite retinoic acid. However, it is unclear how cells control the concentration of the signaling molecule in this negative-feedback loop. We demonstrate in mice that the sequestration of retinyl esters by the enzyme lecithin:retinol acyltransferase (LRAT) is central for this process. Using genetic and pharmacological approaches in mice, we observed that in LRAT deficiency, the transcription factor ISX became hypersensitive to dietary vitamin A and suppressed retinoid biosynthesis. The dysregulation of the pathway resulted in BC accumulation and vitamin A deficiency of extrahepatic tissues. Pharmacological inhibition of retinoid signaling and genetic depletion of the Isx gene restored retinoid biosynthesis in enterocytes. We provide evidence that the catalytic activity of LRAT coordinates the negative-feedback regulation of intestinal retinoid biosynthesis and maintains optimal retinoid levels in the body.
Collapse
Affiliation(s)
- Srinivasagan Ramkumar
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Jean Moon
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Marcin Golczak
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA; Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Johannes von Lintig
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
| |
Collapse
|
5
|
Suh S, Choi EH, Leinonen H, Foik AT, Newby GA, Yeh WH, Dong Z, Kiser PD, Lyon DC, Liu DR, Palczewski K. Restoration of visual function in adult mice with an inherited retinal disease via adenine base editing. Nat Biomed Eng 2021; 5:169-178. [PMID: 33077938 PMCID: PMC7885272 DOI: 10.1038/s41551-020-00632-6] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 09/17/2020] [Indexed: 12/22/2022]
Abstract
Cytosine base editors and adenine base editors (ABEs) can correct point mutations predictably and independent of Cas9-induced double-stranded DNA breaks (which causes substantial indel formation) and homology-directed repair (which typically leads to low editing efficiency). Here, we show, in adult mice, that a subretinal injection of a lentivirus expressing an ABE and a single-guide RNA targeting a de novo nonsense mutation in the Rpe65 gene corrects the pathogenic mutation with up to 29% efficiency and with minimal formation of indel and off-target mutations, despite the absence of the canonical NGG sequence as a protospacer-adjacent motif. The ABE-treated mice displayed restored RPE65 expression and retinoid isomerase activity, and near-normal levels of retinal and visual functions. Our findings motivate the further testing of ABEs for the treatment of inherited retinal diseases and for the correction of pathological mutations with non-canonical protospacer-adjacent motifs.
Collapse
Affiliation(s)
- Susie Suh
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, Irvine, CA, USA.
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA.
| | - Elliot H Choi
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, Irvine, CA, USA
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Henri Leinonen
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, Irvine, CA, USA
| | - Andrzej T Foik
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA, USA
- International Centre for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Wei-Hsi Yeh
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
- Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, USA
| | - Zhiqian Dong
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, Irvine, CA, USA
| | - Philip D Kiser
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA
- Research Service, VA Long Beach Healthcare System, Long Beach, CA, USA
| | - David C Lyon
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, Irvine, CA, USA.
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA.
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA.
| |
Collapse
|
6
|
Widjaja-Adhi MAK, Golczak M. The molecular aspects of absorption and metabolism of carotenoids and retinoids in vertebrates. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158571. [PMID: 31770587 PMCID: PMC7244374 DOI: 10.1016/j.bbalip.2019.158571] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023]
Abstract
Vitamin A is an essential nutrient necessary for numerous basic physiological functions, including reproduction and development, immune cell differentiation and communication, as well as the perception of light. To evade the dire consequences of vitamin A deficiency, vertebrates have evolved specialized metabolic pathways that enable the absorption, transport, and storage of vitamin A acquired from dietary sources as preformed retinoids or provitamin A carotenoids. This evolutionary advantage requires a complex interplay between numerous specialized retinoid-transport proteins, receptors, and enzymes. Recent advances in molecular and structural biology resulted in a rapid expansion of our understanding of these processes at the molecular level. This progress opened new avenues for the therapeutic manipulation of retinoid homeostasis. In this review, we summarize current research related to the biochemistry of carotenoid and retinoid-processing proteins with special emphasis on the structural aspects of their physiological actions. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.
Collapse
Affiliation(s)
- Made Airanthi K Widjaja-Adhi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Marcin Golczak
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America; Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America.
| |
Collapse
|
7
|
Choi EH, Suh S, Sander CL, Hernandez CJO, Bulman ER, Khadka N, Dong Z, Shi W, Palczewski K, Kiser PD. Insights into the pathogenesis of dominant retinitis pigmentosa associated with a D477G mutation in RPE65. Hum Mol Genet 2019; 27:2225-2243. [PMID: 29659842 DOI: 10.1093/hmg/ddy128] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/06/2018] [Indexed: 12/31/2022] Open
Abstract
RPE65 is the essential trans-cis isomerase of the classical retinoid (visual) cycle. Mutations in RPE65 give rise to severe retinal dystrophies, most of which are associated with loss of protein function and recessive inheritance. The only known exception is a c.1430G>A (D477G) mutation that gives rise to dominant retinitis pigmentosa with delayed onset and choroidal and macular involvement. Position 477 is distant from functionally critical regions of RPE65. Hence, the mechanism of D477G pathogenicity remains unclear, although protein misfolding and aggregation mechanisms have been suggested. We characterized a D477G knock-in mouse model which exhibited mild age-dependent changes in retinal structure and function. Immunoblot analysis of protein extracts from the eyes of these knock-in mice demonstrated the presence of ubiquitinated RPE65 and reduced RPE65 expression. We observed an accumulation of retinyl esters in the knock-in mice as well as a delay in rhodopsin regeneration kinetics and diminished electroretinography responses, indicative of RPE65 functional impairment induced by the D477G mutation in vivo. However, a cell line expressing D477G RPE65 revealed protein expression levels, cellular localization and retinoid isomerase activity comparable to cells expressing wild-type protein. Structural analysis of an RPE65 chimera suggested that the D477G mutation does not perturb protein folding or tertiary structure. Instead, the mutation generates an aggregation-prone surface that could induce cellular toxicity through abnormal complex formation as suggested by crystal packing analysis. These results indicate that a toxic gain-of-function induced by the D477G RPE65 substitution may play a role in the pathogenesis of this form of dominant retinitis pigmentosa.
Collapse
Affiliation(s)
- Elliot H Choi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Susie Suh
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Christopher L Sander
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Christian J Ortiz Hernandez
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,University of Puerto Rico at Humacao, Humacao, PR, USA
| | - Elizabeth R Bulman
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA
| | - Nimesh Khadka
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Zhiqian Dong
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Polgenix Inc., Cleveland, OH 44106, USA
| | - Wuxian Shi
- National Synchrotron Light Source-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Philip D Kiser
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.,Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA.,Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| |
Collapse
|