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Yang M, Yao J, Jia L, Kocab AJ, Zacks DN. Preservation of retinal structure and function in two mouse models of inherited retinal degeneration by ONL1204, an inhibitor of the Fas receptor. Cell Death Dis 2024; 15:576. [PMID: 39117629 PMCID: PMC11310419 DOI: 10.1038/s41419-024-06970-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 07/30/2024] [Accepted: 08/01/2024] [Indexed: 08/10/2024]
Abstract
Due to the large number of genes and mutations that result in inherited retinal degenerations (IRD), there has been a paucity of therapeutic options for these patients. There is a large unmet need for therapeutic approaches targeting shared pathophysiologic pathways in a mutation-independent manner. The Fas receptor is a major activator and regulator of retinal cell death and inflammation in a variety of ocular diseases. We previously reported the activation of Fas-mediated photoreceptor (PR) cell death in two different IRD mouse models, rd10 and P23H, and demonstrated the protective effect of genetic Fas inhibition. The purpose of this study was to examine the effects of pharmacologic inhibition of Fas in these two models by intravitreal injection with a small peptide inhibitor of the Fas receptor, ONL1204. A single intravitreal injection of ONL1204 was given to one eye of rd10 mice at P14. Two intravitreal injections of ONL1204 were given to the P23H mice, once at P14 and again at 2-months of age. The fellow eyes were injected with vehicle alone. Fas activation, rate of PR cell death, retinal function, and the activation of immune cells in the retina were evaluated. In both rd10 and P23H mice, ONL1204 treatment resulted in decreased number of TUNEL (+) PRs, decreased caspase 8 activity, enhanced photoreceptor cell counts, and improved visual function compared with vehicle treated fellow eyes. Treatment with ONL1204 also reduced immune cell activation in the retinas of both rd10 and P23H mice. The protective effect of pharmacologic inhibition of Fas by ONL1204 in two distinct mouse models of retinal degeneration suggests that targeting this common pathophysiologic mechanism of cell death and inflammation represents a potential therapeutic approach to preserve the retina in patients with IRD, regardless of the genetic underpinning.
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Affiliation(s)
- Mengling Yang
- Department of Ophthalmology and Visual Sciences, University of Michigan, Kellogg Eye Center, Ann Arbor, MI, USA
- Eye Center of Xiangya Hospital, Xiangya School of medicine, Central South University, Changsha, Hunan, China
| | - Jingyu Yao
- Department of Ophthalmology and Visual Sciences, University of Michigan, Kellogg Eye Center, Ann Arbor, MI, USA
| | - Lin Jia
- Department of Ophthalmology and Visual Sciences, University of Michigan, Kellogg Eye Center, Ann Arbor, MI, USA
| | | | - David N Zacks
- Department of Ophthalmology and Visual Sciences, University of Michigan, Kellogg Eye Center, Ann Arbor, MI, USA.
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2
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Gariballa N, Mohamed F, Badawi S, Ali BR. The double whammy of ER-retention and dominant-negative effects in numerous autosomal dominant diseases: significance in disease mechanisms and therapy. J Biomed Sci 2024; 31:64. [PMID: 38937821 PMCID: PMC11210014 DOI: 10.1186/s12929-024-01054-1] [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: 03/24/2024] [Accepted: 06/20/2024] [Indexed: 06/29/2024] Open
Abstract
The endoplasmic reticulum (ER) employs stringent quality control mechanisms to ensure the integrity of protein folding, allowing only properly folded, processed and assembled proteins to exit the ER and reach their functional destinations. Mutant proteins unable to attain their correct tertiary conformation or form complexes with their partners are retained in the ER and subsequently degraded through ER-associated protein degradation (ERAD) and associated mechanisms. ER retention contributes to a spectrum of monogenic diseases with diverse modes of inheritance and molecular mechanisms. In autosomal dominant diseases, when mutant proteins get retained in the ER, they can interact with their wild-type counterparts. This interaction may lead to the formation of mixed dimers or aberrant complexes, disrupting their normal trafficking and function in a dominant-negative manner. The combination of ER retention and dominant-negative effects has been frequently documented to cause a significant loss of functional proteins, thereby exacerbating disease severity. This review aims to examine existing literature and provide insights into the impact of dominant-negative effects exerted by mutant proteins retained in the ER in a range of autosomal dominant diseases including skeletal and connective tissue disorders, vascular disorders, neurological disorders, eye disorders and serpinopathies. Most crucially, we aim to emphasize the importance of this area of research, offering substantial potential for understanding the factors influencing phenotypic variability associated with genetic variants. Furthermore, we highlight current and prospective therapeutic approaches targeted at ameliorating the effects of mutations exhibiting dominant-negative effects. These approaches encompass experimental studies exploring treatments and their translation into clinical practice.
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Affiliation(s)
- Nesrin Gariballa
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box: 15551, Al-Ain, United Arab Emirates
| | - Feda Mohamed
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box: 15551, Al-Ain, United Arab Emirates
- ASPIRE Precision Medicine Research Institute Abu Dhabi, United Arab Emirates University, Abu Dhabi, United Arab Emirates
| | - Sally Badawi
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box: 15551, Al-Ain, United Arab Emirates
| | - Bassam R Ali
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box: 15551, Al-Ain, United Arab Emirates.
- ASPIRE Precision Medicine Research Institute Abu Dhabi, United Arab Emirates University, Abu Dhabi, United Arab Emirates.
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3
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Cao B, Dahlen JV, Sen M, Beyer T, Leonhard T, Kilger E, Arango-Gonzalez B, Ueffing M. Mutant dominant-negative rhodopsin∆I256 causes protein aggregates degraded via ERAD and prevents normal rhodopsin from proper membrane trafficking. Front Mol Biosci 2024; 11:1369000. [PMID: 38828393 PMCID: PMC11140085 DOI: 10.3389/fmolb.2024.1369000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/23/2024] [Indexed: 06/05/2024] Open
Abstract
Dominant mutations in the rhodopsin gene (Rho) contribute to 25% of autosomal dominant retinitis pigmentosa (adRP), characterized by photoreceptor loss and progressive blindness. One such mutation, Rho ∆I256 , carries a 3-bp deletion, resulting in the loss of one of two isoleucines at codons 255 and 256. Our investigation, using recombinant expression in HEK293 and COS-7 cells, revealed that Rho ∆I256, akin to the known adRP mutation Rho P23H, induces the formation of rhodopsin protein (RHO) aggregates at the perinuclear region. Co-expression of Rho ∆I256 or Rho P23H with wild-type Rho WT, mimicking the heterozygous genotype of adRP patients, demonstrated the dominant-negative effect, as all isoforms were retained in perinuclear aggregates, impeding membrane trafficking. In retinal explants from WT mice, mislocalization of labeled adRP isoforms at the outer nuclear layer was observed. Further analysis revealed that RHO∆I256 aggregates are retained at the endoplasmic reticulum (ER), undergo ER-associated degradation (ERAD), and colocalize with the AAA-ATPase escort chaperone valosin-containing protein (VCP). These aggregates are polyubiquitinated and partially colocalized with the 20S proteasome subunit beta-5 (PSMB5). Pharmacological inhibition of proteasome- or VCP activity increased RHO∆I256 aggregate size. In summary, RHO∆I256 exhibits dominant pathogenicity by sequestering normal RHOWT in ER aggregates, preventing its membrane trafficking and following the ERAD degradation.
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Affiliation(s)
- Bowen Cao
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tuebingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tuebingen, Germany
| | - Johanna Valentina Dahlen
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tuebingen, Germany
| | - Merve Sen
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tuebingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tuebingen, Germany
| | - Tina Beyer
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tuebingen, Germany
| | - Tobias Leonhard
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tuebingen, Germany
| | - Ellen Kilger
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tuebingen, Germany
| | - Blanca Arango-Gonzalez
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tuebingen, Germany
| | - Marius Ueffing
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tuebingen, Germany
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4
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Piccolo D, Zarouchlioti C, Bellingham J, Guarascio R, Ziaka K, Molday RS, Cheetham ME. A Proximity Complementation Assay to Identify Small Molecules That Enhance the Traffic of ABCA4 Misfolding Variants. Int J Mol Sci 2024; 25:4521. [PMID: 38674104 PMCID: PMC11050442 DOI: 10.3390/ijms25084521] [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: 02/29/2024] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 04/28/2024] Open
Abstract
ABCA4-related retinopathy is the most common inherited Mendelian eye disorder worldwide, caused by biallelic variants in the ATP-binding cassette transporter ABCA4. To date, over 2200 ABCA4 variants have been identified, including missense, nonsense, indels, splice site and deep intronic defects. Notably, more than 60% are missense variants that can lead to protein misfolding, mistrafficking and degradation. Currently no approved therapies target ABCA4. In this study, we demonstrate that ABCA4 misfolding variants are temperature-sensitive and reduced temperature growth (30 °C) improves their traffic to the plasma membrane, suggesting the folding of these variants could be rescuable. Consequently, an in vitro platform was developed for the rapid and robust detection of ABCA4 traffic to the plasma membrane in transiently transfected cells. The system was used to assess selected candidate small molecules that were reported to improve the folding or traffic of other ABC transporters. Two candidates, 4-PBA and AICAR, were identified and validated for their ability to enhance both wild-type ABCA4 and variant trafficking to the cell surface in cell culture. We envision that this platform could serve as a primary screen for more sophisticated in vitro testing, enabling the discovery of breakthrough agents to rescue ABCA4 protein defects and mitigate ABCA4-related retinopathy.
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Affiliation(s)
- Davide Piccolo
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - Christina Zarouchlioti
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - James Bellingham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - Rosellina Guarascio
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - Kalliopi Ziaka
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - Robert S. Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada;
| | - Michael E. Cheetham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
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5
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Bighinati A, Adani E, Stanzani A, D’Alessandro S, Marigo V. Molecular mechanisms underlying inherited photoreceptor degeneration as targets for therapeutic intervention. Front Cell Neurosci 2024; 18:1343544. [PMID: 38370034 PMCID: PMC10869517 DOI: 10.3389/fncel.2024.1343544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 01/16/2024] [Indexed: 02/20/2024] Open
Abstract
Retinitis pigmentosa (RP) is a form of retinal degeneration characterized by primary degeneration of rod photoreceptors followed by a secondary cone loss that leads to vision impairment and finally blindness. This is a rare disease with mutations in several genes and high genetic heterogeneity. A challenging effort has been the characterization of the molecular mechanisms underlying photoreceptor cell death during the progression of the disease. Some of the cell death pathways have been identified and comprise stress events found in several neurodegenerative diseases such as oxidative stress, inflammation, calcium imbalance and endoplasmic reticulum stress. Other cell death mechanisms appear more relevant to photoreceptor cells, such as high levels of cGMP and metabolic changes. Here we review some of the cell death pathways characterized in the RP mutant retina and discuss preclinical studies of therapeutic approaches targeting the molecular outcomes that lead to photoreceptor cell demise.
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Affiliation(s)
- Andrea Bighinati
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Elisa Adani
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Agnese Stanzani
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Sara D’Alessandro
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Center for Neuroscience and Neurotechnology, Modena, Italy
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6
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Daich Varela M, Georgiadis A, Michaelides M. Genetic treatment for autosomal dominant inherited retinal dystrophies: approaches, challenges and targeted genotypes. Br J Ophthalmol 2023; 107:1223-1230. [PMID: 36038193 DOI: 10.1136/bjo-2022-321903] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/01/2022] [Indexed: 11/04/2022]
Abstract
Inherited retinal diseases (IRDs) have been in the front line of gene therapy development for the last decade, providing a useful platform to test novel therapeutic approaches. More than 40 clinical trials have been completed or are ongoing, tackling autosomal recessive and X-linked conditions, mostly through adeno-associated viral vector delivery of a normal copy of the disease-causing gene. However, only recently has autosomal dominant (ad) disease been targeted, with the commencement of a trial for rhodopsin (RHO)-associated retinitis pigmentosa (RP), implementing antisense oligonucleotide (AON) therapy, with promising preliminary results (NCT04123626).Autosomal dominant RP represents 15%-25% of all RP, with RHO accounting for 20%-30% of these cases. Autosomal dominant macular and cone-rod dystrophies (MD/CORD) correspond to approximately 7.5% of all IRDs, and approximately 35% of all MD/CORD cases, with the main causative gene being BEST1 Autosomal dominant IRDs are not only less frequent than recessive, but also tend to be less severe and have later onset; for example, an individual with RHO-adRP would typically become severely visually impaired at an age 2-3 times older than in X-linked RPGR-RP.Gain-of-function and dominant negative aetiologies are frequently seen in the prevalent adRP genes RHO, RP1 and PRPF31 among others, which would not be effectively addressed by gene supplementation alone and need creative, novel approaches. Zinc fingers, RNA interference, AON, translational read-through therapy, and gene editing by clustered regularly interspaced short palindromic repeats/Cas are some of the strategies that are currently under investigation and will be discussed here.
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Affiliation(s)
- Malena Daich Varela
- Moorfields Eye Hospital, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | | | - Michel Michaelides
- Moorfields Eye Hospital, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
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7
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Geddes JW, Bondada V, Croall DE, Rodgers DW, Gal J. Impaired activity and membrane association of most calpain-5 mutants causal for neovascular inflammatory vitreoretinopathy. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166747. [PMID: 37207905 PMCID: PMC10332796 DOI: 10.1016/j.bbadis.2023.166747] [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: 07/22/2022] [Revised: 03/29/2023] [Accepted: 05/02/2023] [Indexed: 05/21/2023]
Abstract
Neovascular inflammatory vitreoretinopathy (NIV) is a rare eye disease that ultimately leads to complete blindness and is caused by mutations in the gene encoding calpain-5 (CAPN5), with six pathogenic mutations identified. In transfected SH-SY5Y cells, five of the mutations resulted in decreased membrane association, diminished S-acylation, and reduced calcium-induced autoproteolysis of CAPN5. CAPN5 proteolysis of the autoimmune regulator AIRE was impacted by several NIV mutations. R243, L244, K250 and the adjacent V249 are on β-strands in the protease core 2 domain. Conformational changes induced by Ca2+binding result in these β-strands forming a β-sheet and a hydrophobic pocket which docks W286 side chain away from the catalytic cleft, enabling calpain activation based on comparison with the Ca2+-bound CAPN1 protease core. The pathologic variants R243L, L244P, K250N, and R289W are predicted to disrupt the β-strands, β-sheet, and hydrophobic pocket, impairing calpain activation. The mechanism by which these variants impair membrane association is unclear. G376S impacts a conserved residue in the CBSW domain and is predicted to disrupt a loop containing acidic residues which may contribute to membrane binding. G267S did not impair membrane association and resulted in a slight but significant increase in autoproteolytic and proteolytic activity. However, G267S is also identified in individuals without NIV. Combined with the autosomal dominant pattern of NIV inheritance and evidence that CAPN5 may dimerize, the results are consistent with a dominant negative mechanism for the five pathogenic variants which resulted in impaired CAPN5 activity and membrane association and a gain-of-function for the G267S variant.
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Affiliation(s)
- James W Geddes
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky, Lexington, KY 40536, USA; Department of Neuroscience, University of Kentucky, Lexington, KY 40536, USA.
| | - Vimala Bondada
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky, Lexington, KY 40536, USA
| | - Dorothy E Croall
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469, USA.
| | - David W Rodgers
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, KY 40536, USA.
| | - Jozsef Gal
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky, Lexington, KY 40536, USA; Department of Neuroscience, University of Kentucky, Lexington, KY 40536, USA.
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8
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Sp S, Mitra RN, Zheng M, Chrispell JD, Wang K, Kwon YS, Weiss ER, Han Z. Gene augmentation for autosomal dominant retinitis pigmentosa using rhodopsin genomic loci nanoparticles in the P23H +/- knock-in murine model. Gene Ther 2023; 30:628-640. [PMID: 36935427 DOI: 10.1038/s41434-023-00394-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 02/13/2023] [Accepted: 02/28/2023] [Indexed: 03/21/2023]
Abstract
Gene therapy for autosomal dominant retinitis pigmentosa (adRP) is challenged by the dominant inheritance of the mutant genes, which would seemingly require a combination of mutant suppression and wild-type replacement of the appropriate gene. We explore the possibility that delivery of a nanoparticle (NP)-mediated full-length mouse genomic rhodopsin (gRho) or human genomic rhodopsin (gRHO) locus can overcome the dominant negative effects of the mutant rhodopsin in the clinically relevant P23H+/--knock-in heterozygous mouse model. Our results demonstrate that mice in both gRho and gRHO NP-treated groups exhibit significant structural and functional recovery of the rod photoreceptors, which lasted for 3 months post-injection, indicating a promising reduction in photoreceptor degeneration. We performed miRNA transcriptome analysis using next generation sequencing and detected differentially expressed miRNAs as a first step towards identifying miRNAs that could potentially be used as rhodopsin gene expression enhancers or suppressors for sustained photoreceptor rescue. Our results indicate that delivering an intact genomic locus as a transgene has a greater chance of success compared to the use of the cDNA for treatment of this model of adRP, emphasizing the importance of gene augmentation using a gDNA that includes regulatory elements.
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Affiliation(s)
- Simna Sp
- Department of Ophthalmology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Rajendra N Mitra
- Department of Ophthalmology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Min Zheng
- Department of Ophthalmology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jared D Chrispell
- Department of Cell Biology and Physiology, the University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Kai Wang
- Department of Ophthalmology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Yong-Su Kwon
- Department of Ophthalmology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Ellen R Weiss
- Department of Cell Biology and Physiology, the University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Zongchao Han
- Department of Ophthalmology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- Carolina Institute for NanoMedicine, the University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- Division of Pharmacoengineering & Molecular Pharmaceutics, Eshelman School of Pharmacy, the University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
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9
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Zhao N, Li N, Wang T. PERK prevents rhodopsin degradation during retinitis pigmentosa by inhibiting IRE1-induced autophagy. J Cell Biol 2023; 222:e202208147. [PMID: 37022709 PMCID: PMC10082367 DOI: 10.1083/jcb.202208147] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/04/2023] [Accepted: 02/14/2023] [Indexed: 04/07/2023] Open
Abstract
Chronic endoplasmic reticulum (ER) stress is the underlying cause of many degenerative diseases, including autosomal dominant retinitis pigmentosa (adRP). In adRP, mutant rhodopsins accumulate and cause ER stress. This destabilizes wild-type rhodopsin and triggers photoreceptor cell degeneration. To reveal the mechanisms by which these mutant rhodopsins exert their dominant-negative effects, we established an in vivo fluorescence reporter system to monitor mutant and wild-type rhodopsin in Drosophila. By performing a genome-wide genetic screen, we found that PERK signaling plays a key role in maintaining rhodopsin homeostasis by attenuating IRE1 activities. Degradation of wild-type rhodopsin is mediated by selective autophagy of ER, which is induced by uncontrolled IRE1/XBP1 signaling and insufficient proteasome activities. Moreover, upregulation of PERK signaling prevents autophagy and suppresses retinal degeneration in the adRP model. These findings establish a pathological role for autophagy in this neurodegenerative condition and indicate that promoting PERK activity could be used to treat ER stress-related neuropathies, including adRP.
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Affiliation(s)
- Ning Zhao
- Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Ning Li
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Tao Wang
- Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
- College of Biological Sciences, China Agricultural University, Beijing, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
- National Institute of Biological Sciences, Beijing, China
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10
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Pedraza-González L, Barneschi L, Marszałek M, Padula D, De Vico L, Olivucci M. Automated QM/MM Screening of Rhodopsin Variants with Enhanced Fluorescence. J Chem Theory Comput 2023; 19:293-310. [PMID: 36516450 DOI: 10.1021/acs.jctc.2c00928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We present a computational protocol for the fast and automated screening of excited-state hybrid quantum mechanics/molecular mechanics (QM/MM) models of rhodopsins to be used as fluorescent probes based on the automatic rhodopsin modeling protocol (a-ARM). Such "a-ARM fluorescence screening protocol" is implemented through a general Python-based driver, PyARM, that is also proposed here. The implementation and performance of the protocol are benchmarked using different sets of rhodopsin variants whose absorption and, more relevantly, emission spectra have been experimentally measured. We show that, despite important limitations that make unsafe to use it as a black-box tool, the protocol reproduces the observed trends in fluorescence and it is capable of selecting novel potentially fluorescent rhodopsins. We also show that the protocol can be used in mechanistic investigations to discern fluorescence enhancement effects associated with a near degeneracy of the S1/S2 states or, alternatively, with a barrier generated via coupling of the S0/S1 wave functions.
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Affiliation(s)
- Laura Pedraza-González
- Department of Biotechnology, Chemistry and Pharmacy, Università degli Studi di Siena, Via A. Moro 2, I-53100 Siena, Italy
| | - Leonardo Barneschi
- Department of Biotechnology, Chemistry and Pharmacy, Università degli Studi di Siena, Via A. Moro 2, I-53100 Siena, Italy
| | - Michał Marszałek
- Department of Biotechnology, Chemistry and Pharmacy, Università degli Studi di Siena, Via A. Moro 2, I-53100 Siena, Italy.,Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiaǹskiego 27, 50-370 Wrocław, Poland
| | - Daniele Padula
- Department of Biotechnology, Chemistry and Pharmacy, Università degli Studi di Siena, Via A. Moro 2, I-53100 Siena, Italy
| | - Luca De Vico
- Department of Biotechnology, Chemistry and Pharmacy, Università degli Studi di Siena, Via A. Moro 2, I-53100 Siena, Italy
| | - Massimo Olivucci
- Department of Biotechnology, Chemistry and Pharmacy, Università degli Studi di Siena, Via A. Moro 2, I-53100 Siena, Italy.,Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
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11
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Picarazzi F, Zuanon M, Pasqualetto G, Cammarone S, Romeo I, Young MT, Brancale A, Bassetto M, Mori M. Identification of Small Molecular Chaperones Binding P23H Mutant Opsin through an In Silico Structure-Based Approach. J Chem Inf Model 2022; 62:5794-5805. [PMID: 36367985 DOI: 10.1021/acs.jcim.2c01040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
N-terminal P23H opsin mutation accounts for most of retinitis pigmentosa (RP) cases. P23H functions and folding can be rescued by small chaperone ligands, which contributes to validate mutant opsin as a suitable target for pharmacological treatment of RP. However, the lack of structural details on P23H mutant opsin strongly impairs drug design, and new chemotypes of effective chaperones of P23H opsin are in high demand. Here, a computational-boosted workflow combining homology modeling with molecular dynamics (MD) simulations and virtual screening was used to select putative P23H opsin chaperones among different libraries through a structure-based approach. In vitro studies corroborated the reliability of the structural model generated in this work and identified a number of novel chemotypes of safe and effective chaperones able to promote P23H opsin trafficking to the outer cell membrane.
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Affiliation(s)
- Francesca Picarazzi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Marika Zuanon
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Gaia Pasqualetto
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK
| | - Silvia Cammarone
- Dipartimento di Chimica e Tecnologie del Farmaco, Facoltà di Farmacia e Medicina, "Sapienza" Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Isabella Romeo
- Dipartimento di Chimica e Tecnologie del Farmaco, Facoltà di Farmacia e Medicina, "Sapienza" Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Mark T Young
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Andrea Brancale
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK.,Vysoká Škola Chemicko-Technologiká v Praze, Prague 166 28, Czech Republic
| | - Marcella Bassetto
- Department of Chemistry, Faculty of Science and Engineering, Swansea University, Swansea SA2 8PP, UK
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
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12
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Yao J, Wang T, Jia L, Qiu Y, Zacks DN. Loss of Fas Receptor Function Preserves Photoreceptor Structure and Function in Two Mouse Models of Inherited Retinal Degeneration. Invest Ophthalmol Vis Sci 2022; 63:5. [PMID: 36083588 PMCID: PMC9469031 DOI: 10.1167/iovs.63.10.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The genetic heterogeneity of inherited retinal degeneration (IRD) has limited the development of mutation-specific therapies, necessitating the development of therapeutic approaches targeting broadly shared pathophysiologic pathways. The Fas receptor has been reported as a contributor to retinal cell death and inflammation in a wide variety of ocular diseases. The purpose of this study was to assess targeting the Fas pathway as a novel mutation-independent approach to improve photoreceptor survival in IRD. Methods We examined the effects of genetic inactivation of the Fas receptor on retinal degeneration in two distinct IRD mouse models, P23H and rd10. The Fas-lpr mouse, which contains a functionally inactive Fas receptor, was crossed with the P23H and rd10 mice to generate P23H/Fas-lpr and rd10/Fas-lpr mice. Fas activation, photoreceptor survival and retinal function were assessed. Results We detected elevated levels of Fas receptor and microglial activation in the retinas of both P23H and rd10 mice. Inactivation of Fas in these two IRD models (P23H/Fas-lpr and rd10/Fas-lpr mice) resulted in reduced cell death, increased photoreceptor survival, improved retinal function, and reduced microglial activation and inflammatory cytokine production. Conclusions The protective effect of a nonfunctional Fas receptor in two different mouse models of retinal degeneration suggests that whereas the individual IRD mutation may be specific, the retina's response to the different stressors appears to be shared and driven by Fas. Reducing Fas activity might represent a potential mutation-independent therapeutic approach to preserve retinal structure and function in patients with IRD.
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Affiliation(s)
- Jingyu Yao
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, Michigan, United States
| | - Tiantian Wang
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, Michigan, United States.,Department of Ophthalmology, Xiangya School of Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lin Jia
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, Michigan, United States
| | - Yaoyan Qiu
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, Michigan, United States.,Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
| | - David N Zacks
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, Michigan, United States
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13
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Ziaka K, van der Spuy J. The Role of Hsp90 in Retinal Proteostasis and Disease. Biomolecules 2022; 12:biom12070978. [PMID: 35883534 PMCID: PMC9313453 DOI: 10.3390/biom12070978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 11/24/2022] Open
Abstract
Photoreceptors are sensitive neuronal cells with great metabolic demands, as they are responsible for carrying out visual phototransduction, a complex and multistep process that requires the exquisite coordination of a large number of signalling protein components. Therefore, the viability of photoreceptors relies on mechanisms that ensure a well-balanced and functional proteome that maintains the protein homeostasis, or proteostasis, of the cell. This review explores how the different isoforms of Hsp90, including the cytosolic Hsp90α/β, the mitochondrial TRAP1, and the ER-specific GRP94, are involved in the different proteostatic mechanisms of photoreceptors, and elaborates on Hsp90 function when retinal homeostasis is disturbed. In addition, several studies have shown that chemical manipulation of Hsp90 has significant consequences, both in healthy and degenerating retinae, and this can be partially attributed to the fact that Hsp90 interacts with important photoreceptor-associated client proteins. Here, the interaction of Hsp90 with the retina-specific client proteins PDE6 and GRK1 will be further discussed, providing additional insights for the role of Hsp90 in retinal disease.
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14
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Zhu Y, Cao B, Tolone A, Yan J, Christensen G, Arango-Gonzalez B, Ueffing M, Paquet-Durand F. In vitro Model Systems for Studies Into Retinal Neuroprotection. Front Neurosci 2022; 16:938089. [PMID: 35873807 PMCID: PMC9301112 DOI: 10.3389/fnins.2022.938089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Therapy development for neurodegenerative diseases of the retina constitutes a major unmet medical need, and this may be particularly relevant for inherited diseases of the retina, which are largely untreatable to this day. Therapy development necessitates appropriate models to improve the understanding of the underlying degenerative mechanisms, as well as for the testing and evaluation of novel treatment approaches. This review provides an overview of various in vitro model systems used to study retinal neuroprotection. The in vitro methods and technologies discussed range from primary retinal cell cultures and cell lines, to retinal organoids and organotypic retinal explants, to the cultivation of whole eyeballs. The advantages and disadvantages of these methods are compared and evaluated, also in view of the 3R principles (i.e., the refinement, reduction, and replacement of live animal testing), to identify suitable in vitro alternatives for in vivo experimentation. The article further expands on the use of in vitro models to test and evaluate neuroprotective treatments and to aid the development of retinal drug delivery systems. Among the pharmacological agents tested and characterized in vitro are such that interfere with aberrant cyclic guanosine monophosphate (cGMP) -signaling or such that inhibit the activities of poly (ADP-ribose) polymerase (PARP), histone deacetylases (HDAC), calpain-type proteases, as well as unfolded protein response-related stress. We then introduce nanoparticle-based drug delivery systems and discuss how different in vitro systems may be used to assess their efficacy in the treatment of retinal diseases. The summary provides a brief comparison of available in vitro models and relates their advantages and limitations to the various experimental requirements, for instance, for studies into disease mechanisms, novel treatments, or retinal toxicity. In many cases, combinations of different in vitro models may be required to obtain a comprehensive view of the efficacy of a given retinal neuroprotection approach.
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Affiliation(s)
- Yu Zhu
- Cell Death Mechanisms Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Bowen Cao
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
- Molecular Biology of Retinal Degenerations, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Arianna Tolone
- Cell Death Mechanisms Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Jie Yan
- Cell Death Mechanisms Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Gustav Christensen
- Cell Death Mechanisms Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Blanca Arango-Gonzalez
- Molecular Biology of Retinal Degenerations, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Marius Ueffing
- Molecular Biology of Retinal Degenerations, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- *Correspondence: Marius Ueffing,
| | - François Paquet-Durand
- Cell Death Mechanisms Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- François Paquet-Durand,
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15
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Intartaglia D, Giamundo G, Naso F, Nusco E, Di Giulio S, Salierno FG, Polishchuk E, Conte I. Induction of Autophagy Promotes Clearance of RHOP23H Aggregates and Protects From Retinal Degeneration. Front Aging Neurosci 2022; 14:878958. [PMID: 35847673 PMCID: PMC9281868 DOI: 10.3389/fnagi.2022.878958] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/19/2022] [Indexed: 12/16/2022] Open
Abstract
Autophagy is a critical metabolic process that acts as a major self-digestion and recycling pathway contributing to maintain cellular homeostasis. An emerging field of research supports the therapeutic modulation of autophagy for treating human neurodegenerative disorders, in which toxic aggregates are accumulated in neurons. Our previous study identified Ezrin protein as an inhibitor of autophagy and lysosomal functions in the retina; thus, in turn, identifying it as a potential pharmacological target for increasing retinal cell clearance to treat inherited retinal dystrophies in which misfolded proteins have accumulated. This study aimed to verify the therapeutic inhibition of Ezrin to induce clearance of toxic aggregates in a mouse model for a dominant form of retinitis pigmentosa (i.e., RHOP23H/+). We found that daily inhibition of Ezrin significantly decreased the accumulation of misfolded RHOP23H aggregates. Remarkably, induction of autophagy, by a drug-mediated pulsatile inhibition of Ezrin, promoted the lysosomal clearance of disease-linked RHOP23H aggregates. This was accompanied with a reduction of endoplasmic reticulum (ER)-stress, robust decrease of photoreceptors' cell death, amelioration in both retinal morphology and function culminating in a better preservation of vision. Our study opens new perspectives for a pulsatile pharmacological induction of autophagy as a mutation-independent therapy paving the way toward a more effective therapeutic strategy to treat these devastating retinal disorders due to an accumulation of intracellular toxic aggregates.
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Affiliation(s)
| | - Giuliana Giamundo
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Federica Naso
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Edoardo Nusco
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | | | | | | | - Ivan Conte
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
- Department of Biology, University of Naples Federico II, Naples, Italy
- *Correspondence: Ivan Conte
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16
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Vats A, Xi Y, Feng B, Clinger OD, St Leger AJ, Liu X, Ghosh A, Dermond CD, Lathrop KL, Tochtrop GP, Picaud S, Chen Y. Non-retinoid chaperones improve rhodopsin homeostasis in a mouse model of retinitis pigmentosa. JCI Insight 2022; 7:153717. [PMID: 35472194 PMCID: PMC9220944 DOI: 10.1172/jci.insight.153717] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 04/20/2022] [Indexed: 11/17/2022] Open
Abstract
Rhodopsin-associated (RHO-associated) retinitis pigmentosa (RP) is a progressive retinal disease that currently has no cure. RHO protein misfolding leads to disturbed proteostasis and the death of rod photoreceptors, resulting in decreased vision. We previously identified nonretinoid chaperones of RHO, including YC-001 and F5257-0462, by small-molecule high-throughput screening. Here, we profile the chaperone activities of these molecules toward the cell-surface level of 27 RP-causing human RHO mutants in NIH3T3 cells. Furthermore, using retinal explant culture, we show that YC-001 improves retinal proteostasis by supporting RHO homeostasis in RhoP23H/+ mouse retinae, which results in thicker outer nuclear layers (ONL), indicating delayed photoreceptor degeneration. Interestingly, YC-001 ameliorated retinal immune responses and reduced the number of microglia/macrophages in the RhoP23H/+ retinal explants. Similarly, F5257-0462 also protects photoreceptors in RhoP23H/+ retinal explants. In vivo, intravitreal injection of YC-001 or F5257-0462 microparticles in PBS shows that F5257-0462 has a higher efficacy in preserving photoreceptor function and delaying photoreceptor death in RhoP23H/+ mice. Collectively, we provide proof of principle that nonretinoid chaperones are promising drug candidates in treating RHO-associated RP.
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Affiliation(s)
- Abhishek Vats
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Yibo Xi
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Bing Feng
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Owen D Clinger
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Anthony J St Leger
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Xujie Liu
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Archisha Ghosh
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Chase D Dermond
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Kira L Lathrop
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
| | - Gregory P Tochtrop
- Department of Chemistry, Case Western Reserve University, Cleveland, United States of America
| | - Serge Picaud
- Institut de la Vision, Sorbonne Université, Paris, France
| | - Yuanyuan Chen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States of America
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17
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McLaughlin T, Medina A, Perkins J, Yera M, Wang JJ, Zhang SX. Cellular stress signaling and the unfolded protein response in retinal degeneration: mechanisms and therapeutic implications. Mol Neurodegener 2022; 17:25. [PMID: 35346303 PMCID: PMC8962104 DOI: 10.1186/s13024-022-00528-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 03/04/2022] [Indexed: 12/22/2022] Open
Abstract
Background The retina, as part of the central nervous system (CNS) with limited capacity for self-reparation and regeneration in mammals, is under cumulative environmental stress due to high-energy demands and rapid protein turnover. These stressors disrupt the cellular protein and metabolic homeostasis, which, if not alleviated, can lead to dysfunction and cell death of retinal neurons. One primary cellular stress response is the highly conserved unfolded protein response (UPR). The UPR acts through three main signaling pathways in an attempt to restore the protein homeostasis in the endoplasmic reticulum (ER) by various means, including but not limited to, reducing protein translation, increasing protein-folding capacity, and promoting misfolded protein degradation. Moreover, recent work has identified a novel function of the UPR in regulation of cellular metabolism and mitochondrial function, disturbance of which contributes to neuronal degeneration and dysfunction. The role of the UPR in retinal neurons during aging and under disease conditions in age-related macular degeneration (AMD), retinitis pigmentosa (RP), glaucoma, and diabetic retinopathy (DR) has been explored over the past two decades. Each of the disease conditions and their corresponding animal models provide distinct challenges and unique opportunities to gain a better understanding of the role of the UPR in the maintenance of retinal health and function. Method We performed an extensive literature search on PubMed and Google Scholar using the following keywords: unfolded protein response, metabolism, ER stress, retinal degeneration, aging, age-related macular degeneration, retinitis pigmentosa, glaucoma, diabetic retinopathy. Results and conclusion We summarize recent advances in understanding cellular stress response, in particular the UPR, in retinal diseases, highlighting the potential roles of UPR pathways in regulation of cellular metabolism and mitochondrial function in retinal neurons. Further, we provide perspective on the promise and challenges for targeting the UPR pathways as a new therapeutic approach in age- and disease-related retinal degeneration.
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Affiliation(s)
- Todd McLaughlin
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA
| | - Andy Medina
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA
| | - Jacob Perkins
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA
| | - Maria Yera
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA.,Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Joshua J Wang
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA.,Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Sarah X Zhang
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA. .,Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA. .,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA.
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18
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Pedraza-González L, Barneschi L, Padula D, De Vico L, Olivucci M. Evolution of the Automatic Rhodopsin Modeling (ARM) Protocol. Top Curr Chem (Cham) 2022; 380:21. [PMID: 35291019 PMCID: PMC8924150 DOI: 10.1007/s41061-022-00374-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/29/2022] [Indexed: 10/27/2022]
Abstract
In recent years, photoactive proteins such as rhodopsins have become a common target for cutting-edge research in the field of optogenetics. Alongside wet-lab research, computational methods are also developing rapidly to provide the necessary tools to analyze and rationalize experimental results and, most of all, drive the design of novel systems. The Automatic Rhodopsin Modeling (ARM) protocol is focused on providing exactly the necessary computational tools to study rhodopsins, those being either natural or resulting from mutations. The code has evolved along the years to finally provide results that are reproducible by any user, accurate and reliable so as to replicate experimental trends. Furthermore, the code is efficient in terms of necessary computing resources and time, and scalable in terms of both number of concurrent calculations as well as features. In this review, we will show how the code underlying ARM achieved each of these properties.
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Affiliation(s)
- Laura Pedraza-González
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy. .,Department of Chemistry and Industrial Chemistry, University of Pisa, Via Moruzzi 13, 56124, Pisa, Italy.
| | - Leonardo Barneschi
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy
| | - Daniele Padula
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy
| | - Luca De Vico
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy.
| | - Massimo Olivucci
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100, Siena, Italy. .,Department of Chemistry, Bowling Green State University, Bowling Green, OH, 43403, USA.
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19
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Zhao M, Lv H, Yang N, Peng GH. Rapamycin Improved Retinal Function and Morphology in a Mouse Model of Retinal Degeneration. Front Neurosci 2022; 16:846584. [PMID: 35295093 PMCID: PMC8919089 DOI: 10.3389/fnins.2022.846584] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 01/31/2022] [Indexed: 12/15/2022] Open
Abstract
The retina is an important visual organ, which is responsible for receiving light signals and transmitting them to the optic nerve center step by step. The retina contains a variety of cells, among which photoreceptor cells receive light signals and convert them into nerve signals, and are mainly responsible for light and dark vision. Retinal degeneration is mainly the degeneration of photoreceptor cells, and retinitis pigmentosa (RP) is characterized by rod degeneration followed by cone degeneration. So far, there is still a lack of effective drugs to treat RP. Here, we established a stable RP model by tail vein injection of methyl methanesulfonate to study the mechanism of retinal photoreceptor degeneration. Mechanistic target of rapamycin (mTOR) is located in the central pathway of growth and energy metabolism and changes in a variety of diseases in response to pathological changes. We found that the mTOR was activated in this model. Therefore, the inhibitor of mTOR, rapamycin was used to suppress the expression of mTOR and interfere with photoreceptor degeneration. Electroretinogram assay showed that the function of mice retina was improved. Hematoxylin and eosin staining results displayed that retinal photoreceptor thickness and morphology were improved. Also, the autophagy in rapamycin group was activated, which revealed that rapamycin may protect the retinal photoreceptor by inhibiting mTOR and then activating autophagy.
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Affiliation(s)
- Meng Zhao
- Laboratory of Visual Cell Differentiation and Regulation, Basic Medical College, Zhengzhou University, Zhengzhou, China
- Department of Pathophysiology, Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - Houting Lv
- Laboratory of Visual Cell Differentiation and Regulation, Basic Medical College, Zhengzhou University, Zhengzhou, China
- Department of Pathophysiology, Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - Na Yang
- Laboratory of Visual Cell Differentiation and Regulation, Basic Medical College, Zhengzhou University, Zhengzhou, China
- Department of Pathophysiology, Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - Guang-Hua Peng
- Laboratory of Visual Cell Differentiation and Regulation, Basic Medical College, Zhengzhou University, Zhengzhou, China
- Department of Pathophysiology, Basic Medical College, Zhengzhou University, Zhengzhou, China
- *Correspondence: Guang-Hua Peng,
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20
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Ortega JT, Jastrzebska B. Rhodopsin as a Molecular Target to Mitigate Retinitis Pigmentosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1371:61-77. [PMID: 34962636 DOI: 10.1007/5584_2021_682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Retinitis pigmentosa (RP) is a group of hereditary degenerative diseases affecting 1 of 4000 people worldwide and being the most prevalent cause of visual handicap among working populations in developed countries. These disorders are mainly related to the abnormalities in the rod G protein-coupled receptor (GPCR), rhodopsin reflected in the dysregulated membrane trafficking, stability and phototransduction processes that lead to progressive loss of retina function and eventually blindness. Currently, there is no cure for RP, and the therapeutic options are limited. Targeting rhodopsin with small molecule chaperones to improve the folding and stability of the mutant receptor is one of the most promising pharmacological approaches to alleviate the pathology of RP. This review provides an update on the current knowledge regarding small molecule compounds that have been evaluated as rhodopsin modulators to be considered as leads for the development of novel therapies for RP.
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Affiliation(s)
- Joseph T Ortega
- Department of Pharmacology, School of Medicine, Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH, USA
| | - Beata Jastrzebska
- Department of Pharmacology, School of Medicine, Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH, USA.
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21
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Felline A, Schiroli D, Comitato A, Marigo V, Fanelli F. Structure network-based landscape of rhodopsin misfolding by mutations and algorithmic prediction of small chaperone action. Comput Struct Biotechnol J 2021; 19:6020-6038. [PMID: 34849206 PMCID: PMC8605067 DOI: 10.1016/j.csbj.2021.10.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/09/2021] [Accepted: 10/31/2021] [Indexed: 11/28/2022] Open
Abstract
Failure of a protein to achieve its functional structural state and normal cellular location contributes to the etiology and pathology of heritable human conformational diseases. The autosomal dominant form of retinitis pigmentosa (adRP) is an incurable blindness largely linked to mutations of the membrane protein rod opsin. While the mechanisms underlying the noxious effects of the mutated protein are not completely understood, a common feature is the functional protein conformational loss. Here, the wild type and 39 adRP rod opsin mutants were subjected to mechanical unfolding simulations coupled to the graph theory-based protein structure network analysis. A robust computational model was inferred and in vitro validated in its ability to predict endoplasmic reticulum retention of adRP mutants, a feature linked to the mutation-caused misfolding. The structure-based approach could also infer the structural determinants of small chaperone action on misfolded protein mutants with therapeutic implications. The approach is exportable to conformational diseases linked to missense mutations in any membrane protein.
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Affiliation(s)
- Angelo Felline
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy
| | - Davide Schiroli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Antonella Comitato
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy.,Center for Neuroscience and Neurotechnology, Italy
| | - Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy.,Center for Neuroscience and Neurotechnology, Italy
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22
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TRAP1 in Oxidative Stress and Neurodegeneration. Antioxidants (Basel) 2021; 10:antiox10111829. [PMID: 34829705 PMCID: PMC8614808 DOI: 10.3390/antiox10111829] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/13/2021] [Accepted: 11/15/2021] [Indexed: 12/22/2022] Open
Abstract
Tumor necrosis factor receptor-associated protein 1 (TRAP1), also known as heat shock protein 75 (HSP75), is a member of the heat shock protein 90 (HSP90) chaperone family that resides mainly in the mitochondria. As a mitochondrial molecular chaperone, TRAP1 supports protein folding and contributes to the maintenance of mitochondrial integrity even under cellular stress. TRAP1 is a cellular regulator of mitochondrial bioenergetics, redox homeostasis, oxidative stress-induced cell death, apoptosis, and unfolded protein response (UPR) in the endoplasmic reticulum (ER). TRAP1 has attracted increasing interest as a therapeutical target, with a special focus on the design of TRAP1 specific inhibitors. Although TRAP1 was extensively studied in the oncology field, its role in central nervous system cells, under physiological and pathological conditions, remains largely unknown. In this review, we will start by summarizing the biology of TRAP1, including its structure and related pathways. Thereafter, we will continue by debating the role of TRAP1 in the maintenance of redox homeostasis and protection against oxidative stress and apoptosis. The role of TRAP1 in neurodegenerative disorders will also be discussed. Finally, we will review the potential of TRAP1 inhibitors as neuroprotective drugs.
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23
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Pharmacological Inhibition of the VCP/Proteasome Axis Rescues Photoreceptor Degeneration in RHO P23H Rat Retinal Explants. Biomolecules 2021; 11:biom11101528. [PMID: 34680161 PMCID: PMC8534135 DOI: 10.3390/biom11101528] [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: 08/13/2021] [Revised: 10/02/2021] [Accepted: 10/13/2021] [Indexed: 12/13/2022] Open
Abstract
Rhodopsin (RHO) misfolding mutations are a common cause of the blinding disease autosomal dominant retinitis pigmentosa (adRP). The most prevalent mutation, RHOP23H, results in its misfolding and retention in the endoplasmic reticulum (ER). Under homeostatic conditions, misfolded proteins are selectively identified, retained at the ER, and cleared via ER-associated degradation (ERAD). Overload of these degradation processes for a prolonged period leads to imbalanced proteostasis and may eventually result in cell death. ERAD of misfolded proteins, such as RHOP23H, includes the subsequent steps of protein recognition, targeting for ERAD, retrotranslocation, and proteasomal degradation. In the present study, we investigated and compared pharmacological modulation of ERAD at these four different major steps. We show that inhibition of the VCP/proteasome activity favors cell survival and suppresses P23H-mediated retinal degeneration in RHOP23H rat retinal explants. We suggest targeting this activity as a therapeutic approach for patients with currently untreatable adRP.
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Maldonado R, Jalil S, Wartiovaara K. Curative gene therapies for rare diseases. J Community Genet 2021; 12:267-276. [PMID: 32803721 PMCID: PMC8141081 DOI: 10.1007/s12687-020-00480-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/29/2020] [Indexed: 02/06/2023] Open
Abstract
Diseases caused by alterations in the DNA can be overcome by providing the cells or tissues with a functional copy of the mutated gene. The most common form of gene therapy implies adding an extra genetic unit into the cell. However, new genome engineering techniques also allow the modification or correction of the existing allele, providing new possibilities, especially for dominant diseases. Gene therapies have been tested for 30 years in thousands of clinical trials, but presently, we have only three authorised gene therapy products for the treatment of inherited diseases in European Union. Here, we describe the gene therapy alternatives already on the market in the European Union and expand the scope to some clinical trials. Additionally, we discuss the ethical and regulatory issues raised by the development of these new kinds of therapies.
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Affiliation(s)
- Rocio Maldonado
- Stem Cells and Metabolism Research Program, University of Helsinki, Helsinki, Finland
| | - Sami Jalil
- Stem Cells and Metabolism Research Program, University of Helsinki, Helsinki, Finland
| | - Kirmo Wartiovaara
- Stem Cells and Metabolism Research Program, University of Helsinki, Helsinki, Finland.
- Clinical Genetics, Helsinki University Hospital, Helsinki, Finland.
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Singh RK, Binette F, Seiler M, Petersen-Jones SM, Nasonkin IO. Pluripotent Stem Cell-Based Organoid Technologies for Developing Next-Generation Vision Restoration Therapies of Blindness. J Ocul Pharmacol Ther 2021; 37:147-156. [PMID: 33052761 PMCID: PMC8060716 DOI: 10.1089/jop.2020.0016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 07/28/2020] [Indexed: 12/25/2022] Open
Abstract
Blindness, associated with death of retinal cells at the back of the eye, is caused by a number of conditions with high prevalence such as glaucoma, age-related macular degeneration, and diabetic retinopathy. In addition, a large number of orphan inherited (mostly monogenic) conditions, such as retinitis pigmentosa and Leber Congenital Amaurosis, add to the overall number of patients with blinding retinal degenerative diseases. Blindness caused by deterioration and loss of retina is so far incurable. Modern biomedical research leveraging molecular and regenerative medicine approaches had a number of groundbreaking discoveries and proof-of-principle treatments of blindness in animals. However, these methods are slow to be standardized and commercialized as therapies to benefit people losing their eyesight due to retinal degenerative conditions. In this review, we will outline major regenerative medicine approaches, which are emerging as promising for preserving or/and restoring vision. We discuss the potential of each of these approaches to reach commercialization step and be converted to treatments, which could at least ameliorate blindness caused by retinal cell death.
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Affiliation(s)
| | | | - Magdalene Seiler
- Stem Cell Research Center, University of California, Irvine, Irvine, California, USA
- Department of Physical Medicine & Rehabilitation, University of California, Irvine, Irvine, California, USA
- Department of Ophthalmology, University of California, Irvine, Irvine, California, USA
- Department of Anatomy & Neurobiology, University of California, Irvine, Irvine, California, USA
| | - Simon M. Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
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Fanelli F, Felline A, Marigo V. Structural aspects of rod opsin and their implication in genetic diseases. Pflugers Arch 2021; 473:1339-1359. [PMID: 33728518 DOI: 10.1007/s00424-021-02546-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/17/2021] [Accepted: 02/22/2021] [Indexed: 01/04/2023]
Abstract
Vision in dim-light conditions is triggered by photoactivation of rhodopsin, the visual pigment of rod photoreceptor cells. Rhodopsin is made of a protein, the G protein coupled receptor (GPCR) opsin, and the chromophore 11-cis-retinal. Vertebrate rod opsin is the GPCR best characterized at the atomic level of detail. Since the release of the first crystal structure 20 years ago, a huge number of structures have been released that, in combination with valuable spectroscopic determinations, unveiled most aspects of the photobleaching process. A number of spontaneous mutations of rod opsin have been found linked to vision-impairing diseases like autosomal dominant or autosomal recessive retinitis pigmentosa (adRP or arRP, respectively) and autosomal congenital stationary night blindness (adCSNB). While adCSNB is mainly caused by constitutive activation of rod opsin, RP shows more variegate determinants affecting different aspects of rod opsin function. The vast majority of missense rod opsin mutations affects folding and trafficking and is linked to adRP, an incurable disease that awaits light on its molecular structure determinants. This review article summarizes all major structural information available on vertebrate rod opsin conformational states and the insights gained so far into the structural determinants of adCSNB and adRP linked to rod opsin mutations. Strategies to design small chaperones with therapeutic potential for selected adRP rod opsin mutants will be discussed as well.
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Affiliation(s)
- Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125, Modena, Italy. .,Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, via Campi 287, Modena, 41125, Italy.
| | - Angelo Felline
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125, Modena, Italy
| | - Valeria Marigo
- Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, via Campi 287, Modena, 41125, Italy.,Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125, Modena, Italy
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Vasudevan S, Park PSH. Differential Aggregation Properties of Mutant Human and Bovine Rhodopsin. Biochemistry 2020; 60:6-18. [PMID: 33356167 DOI: 10.1021/acs.biochem.0c00733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rhodopsin is the light receptor required for the function and health of photoreceptor cells. Mutations in rhodopsin can cause misfolding and aggregation of the receptor, which leads to retinal degeneration. Bovine rhodopsin is often used as a model to understand the effect of pathogenic mutations in rhodopsin due to the abundance of structural information on the bovine form of the receptor. It is unclear whether or not the bovine rhodopsin template is adequate in predicting the effect of these mutations occurring in human retinal disease or in predicting the efficacy of therapeutic strategies. To better understand the extent to which bovine rhodopsin can serve as a model, human and bovine P23H rhodopsin mutants expressed heterologously in cells were examined. The aggregation properties and cellular localization of the mutant receptors were determined by Förster resonance energy transfer and confocal microscopy. The potential therapeutic effects of the pharmacological compounds 9-cis retinal and metformin were also examined. Human and bovine P23H rhodopsin mutants exhibited different aggregation properties and responses to the pharmacological compounds tested. These observations would lead to different predictions on the severity of the phenotype and divergent predictions on the benefit of the therapeutic compounds tested. The bovine rhodopsin template does not appear to adequately model the effects of the P23H mutation in the human form of the receptor.
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Affiliation(s)
- Sreelakshmi Vasudevan
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio 44106, United States
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Liu J, Taylor RL, Baines RA, Swanton L, Freeman S, Corneo B, Patel A, Marmorstein A, Knudsen T, Black GC, Manson F. Small Molecules Restore Bestrophin 1 Expression and Function of Both Dominant and Recessive Bestrophinopathies in Patient-Derived Retinal Pigment Epithelium. Invest Ophthalmol Vis Sci 2020; 61:28. [PMID: 32421148 PMCID: PMC7405785 DOI: 10.1167/iovs.61.5.28] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Purpose Bestrophinopathies are a group of untreatable inherited retinal dystrophies caused by mutations in the retinal pigment epithelium (RPE) Cl− channel bestrophin 1. We tested whether sodium phenylbutyrate (4PBA) could rescue the function of mutant bestrophin 1 associated with autosomal dominant and recessive disease. We then sought analogues of 4PBA with increased potency and determined the mode of action for 4PBA and a lead compound 2-naphthoxyacetic acid (2-NOAA). Lastly, we tested if 4PBA and 2-NOAA could functionally rescue bestrophin 1 function in RPE generated from induced pluripotent stem cells (iPSC-RPEs) derived from patients with a dominant or recessive bestrophinopathy. Methods Global and plasma membrane expression was determined by Western blot and immunofluorescent microscopy, respectively. The effect of 4PBA and 2-NOAA on transcription was measured by quantitative RT-PCR and the rate of protein turnover by cycloheximide chase and Western blot. Channel function was measured by whole-cell patch clamp. Results 4PBA and 2-NOAA can rescue the global and membrane expression of mutant bestrophin 1 associated with autosomal dominant disease (Best vitelliform macular dystrophy [BVMD]) and autosome recessive bestrophinopathy (ARB), and these small molecules have different modes of action. Both 4PBA and 2-NOAA significantly increased the channel function of mutant BVMD and ARB bestrophin 1 in HEK293T and iPSC-RPE cells derived from patients with BVMD and ARB. For 4PBA, the increased mutant channel function in BVMD and ARB iPSC-RPE was equal to that of wild-type iPSC-RPE bestrophin 1. Conclusions The restoration of bestrophin 1 function in patient-derived RPE confirms the US Food and Drug Administration–approved drug 4PBA as a promising therapeutic treatment for bestrophinopathies.
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Newton F, Megaw R. Mechanisms of Photoreceptor Death in Retinitis Pigmentosa. Genes (Basel) 2020; 11:genes11101120. [PMID: 32987769 PMCID: PMC7598671 DOI: 10.3390/genes11101120] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/15/2020] [Accepted: 09/22/2020] [Indexed: 02/08/2023] Open
Abstract
Retinitis pigmentosa (RP) is the most common cause of inherited blindness and is characterised by the progressive loss of retinal photoreceptors. However, RP is a highly heterogeneous disease and, while much progress has been made in developing gene replacement and gene editing treatments for RP, it is also necessary to develop treatments that are applicable to all causative mutations. Further understanding of the mechanisms leading to photoreceptor death is essential for the development of these treatments. Recent work has therefore focused on the role of apoptotic and non-apoptotic cell death pathways in RP and the various mechanisms that trigger these pathways in degenerating photoreceptors. In particular, several recent studies have begun to elucidate the role of microglia and innate immune response in the progression of RP. Here, we discuss some of the recent progress in understanding mechanisms of rod and cone photoreceptor death in RP and summarise recent clinical trials targeting these pathways.
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Affiliation(s)
- Fay Newton
- MRC Human Genetics Unit, University of Edinburgh, South Bridge, Edinburgh EH8 9YL, UK;
- Correspondence:
| | - Roly Megaw
- MRC Human Genetics Unit, University of Edinburgh, South Bridge, Edinburgh EH8 9YL, UK;
- Princess Alexandra Eye Pavilion, NHS Lothian, Edinburgh EH3 9HA, UK
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Narasimhan I, Murali A, Subramanian K, Ramalingam S, Parameswaran S. Autosomal dominant retinitis pigmentosa with toxic gain of function: Mechanisms and therapeutics. Eur J Ophthalmol 2020; 31:304-320. [PMID: 32962414 DOI: 10.1177/1120672120957605] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Autosomal dominant retinitis pigmentosa is a form of retinitis pigmentosa, an inherited retinal degenerative disorder characterized by progressive loss of photoreceptors eventually leading to irreversible loss of vision. Mutations in genes involved in the basic functions of the visual system give rise to this condition. These mutations can either lead to loss of function or toxic gain of function phenotypes. While autosomal dominant retinitis pigmentosa caused by loss of function can be ideally treated by gene supplementation with a single vector to address a different spectrum of mutations in a gene, the same strategy cannot be applied to toxic gain of function phenotypes. In toxic gain of function phenotypes, the mutation in the gene results in the acquisition of a new function that can interrupt the functioning of the wildtype protein by various mechanisms leading to cell toxicity, thus making a single approach impractical. This review focuses on the genes and mechanisms that cause toxic gain of function phenotypes associated with autosomal dominant retinitis pigmentosa and provide a bird's eye view on current therapeutic strategies and ongoing clinical trials.
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Affiliation(s)
- Ishwarya Narasimhan
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Aishwarya Murali
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Krishnakumar Subramanian
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Sivaprakash Ramalingam
- Genomics and Molecular Medicine Unit, Council of Scientific and Industrial Research - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Sowmya Parameswaran
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
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Orlans HO, Barnard AR, Patrício MI, McClements ME, MacLaren RE. Effect of AAV-Mediated Rhodopsin Gene Augmentation on Retinal Degeneration Caused by the Dominant P23H Rhodopsin Mutation in a Knock-In Murine Model. Hum Gene Ther 2020; 31:730-742. [DOI: 10.1089/hum.2020.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Harry O. Orlans
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Alun R. Barnard
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, United Kingdom
| | - Maria I. Patrício
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, United Kingdom
| | | | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
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Liu X, Feng B, Vats A, Tang H, Seibel W, Swaroop M, Tawa G, Zheng W, Byrne L, Schurdak M, Chen Y. Pharmacological clearance of misfolded rhodopsin for the treatment of RHO-associated retinitis pigmentosa. FASEB J 2020; 34:10146-10167. [PMID: 32536017 DOI: 10.1096/fj.202000282r] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/07/2020] [Accepted: 05/15/2020] [Indexed: 01/20/2023]
Abstract
Rhodopsin mutation and misfolding is a common cause of autosomal dominant retinitis pigmentosa (RP). Using a luciferase reporter assay, we undertook a small-molecule high-throughput screening (HTS) of 68, 979 compounds and identified nine compounds that selectively reduced the misfolded P23H rhodopsin without an effect on the wild type (WT) rhodopsin protein. Further, we found five of these compounds, including methotrexate (MTX), promoted P23H rhodopsin degradation that also cleared out other misfolded rhodopsin mutant proteins. We showed MTX increased P23H rhodopsin degradation via the lysosomal but not the proteasomal pathway. Importantly, one intravitreal injection (IVI) of 25 pmol MTX increased electroretinogram (ERG) response and rhodopsin level in the retinae of RhoP23H/+ knock-in mice at 1 month of age. Additionally, four weekly IVIs increased the photoreceptor cell number in the retinae of RhoP23H/+ mice compared to vehicle control. Our study indicates a therapeutic potential of repurposing MTX for the treatment of rhodopsin-associated RP.
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Affiliation(s)
- Xujie Liu
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bing Feng
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Abhishek Vats
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hong Tang
- Drug Discovery Center, University of Cincinnati, Cincinnati, OH, USA
| | - William Seibel
- Drug Discovery Center, University of Cincinnati, Cincinnati, OH, USA.,Oncology Department, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Manju Swaroop
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Gregory Tawa
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Wei Zheng
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Leah Byrne
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mark Schurdak
- Drug Discovery Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yuanyuan Chen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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Piano I, D'Antongiovanni V, Novelli E, Biagioni M, Dei Cas M, Paroni RC, Ghidoni R, Strettoi E, Gargini C. Myriocin Effect on Tvrm4 Retina, an Autosomal Dominant Pattern of Retinitis Pigmentosa. Front Neurosci 2020; 14:372. [PMID: 32435178 PMCID: PMC7218082 DOI: 10.3389/fnins.2020.00372] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 03/26/2020] [Indexed: 02/01/2023] Open
Abstract
Tvrm4 mice, a model of autosomal dominant retinitis pigmentosa (RP), carry a mutation of Rhodopsin gene that can be activated by brief exposure to very intense light. Here, we test the possibility of an anatomical, metabolic, and functional recovery by delivering to degenerating Tvrm4 animals, Myriocin, an inhibitor of ceramide de novo synthesis previously shown to effectively slow down retinal degeneration in rd10 mutants (Strettoi et al., 2010; Piano et al., 2013). Different routes and durations of Myriocin administration were attempted by using either single intravitreal (i.v.) or long-term, repeated intraperitoneal (i.p.) injections. The retinal function of treated and control animals was tested by ERG recordings. Retinas from ERG-recorded animals were studied histologically to reveal the extent of photoreceptor death. A correlation was observed between Myriocin administration, lowering of retinal ceramides, and preservation of ERG responses in i.v. injected cases. Noticeably, the i.p. treatment with Myriocin decreased the extension of the retinal-degenerating area, preserved the ERG response, and correlated with decreased levels of biochemical indicators of retinal oxidative damage. The results obtained in this study confirm the efficacy of Myriocin in slowing down retinal degeneration in genetic models of RP independently of the underlying mutation responsible for the disease, likely targeting ceramide-dependent, downstream pathways. Alleviation of retinal oxidative stress upon Myriocin treatment suggests that this molecule, or yet unidentified metabolites, act on cellular detoxification systems supporting cell survival. Altogether, the pharmacological approach chosen here meets the necessary pre-requisites for translation into human therapy to slow down RP.
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Affiliation(s)
- Ilaria Piano
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | | | | | - Michele Dei Cas
- Department of Health Sciences, University of Milan, Milan, Italy
| | | | - Riccardo Ghidoni
- Department of Health Sciences, University of Milan, Milan, Italy.,Aldo Ravelli Center, University of Milan, Milan, Italy
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Gorbatyuk MS, Starr CR, Gorbatyuk OS. Endoplasmic reticulum stress: New insights into the pathogenesis and treatment of retinal degenerative diseases. Prog Retin Eye Res 2020; 79:100860. [PMID: 32272207 DOI: 10.1016/j.preteyeres.2020.100860] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 03/08/2020] [Accepted: 03/17/2020] [Indexed: 12/13/2022]
Abstract
Physiological equilibrium in the retina depends on coordinated work between rod and cone photoreceptors and can be compromised by the expression of mutant proteins leading to inherited retinal degeneration (IRD). IRD is a diverse group of retinal dystrophies with multifaceted molecular mechanisms that are not fully understood. In this review, we focus on the contribution of chronically activated unfolded protein response (UPR) to inherited retinal pathogenesis, placing special emphasis on studies employing genetically modified animal models. As constitutively active UPR in degenerating retinas may activate pro-apoptotic programs associated with oxidative stress, pro-inflammatory signaling, dysfunctional autophagy, free cytosolic Ca2+ overload, and altered protein synthesis rate in the retina, we focus on the regulatory mechanisms of translational attenuation and approaches to overcoming translational attenuation in degenerating retinas. We also discuss current research on the role of the UPR mediator PERK and its downstream targets in degenerating retinas and highlight the therapeutic benefits of reprogramming PERK signaling in preclinical animal models of IRD. Finally, we describe pharmacological approaches targeting UPR in ocular diseases and consider their potential applications to IRD.
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Affiliation(s)
- Marina S Gorbatyuk
- The University of Alabama at Birmingham, Department of Optometry and Vision Science, School of Optometry, USA.
| | - Christopher R Starr
- The University of Alabama at Birmingham, Department of Optometry and Vision Science, School of Optometry, USA
| | - Oleg S Gorbatyuk
- The University of Alabama at Birmingham, Department of Optometry and Vision Science, School of Optometry, USA
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35
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Kimura Y, Kawai-Noma S, Saito K, Umeno D. Directed Evolution of the Stringency of the LuxR Vibrio fischeri Quorum Sensor without OFF-State Selection. ACS Synth Biol 2020; 9:567-575. [PMID: 31999435 DOI: 10.1021/acssynbio.9b00444] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Stringency (low leak) is one of the most important specifications required for genetic circuits and induction systems, but it is challenging to evolve without sacrificing the maximum output level. This problem also comes from the absence of truly tunable negative selection methods. This paper reports that stringently switching variants can sometimes emerge with surprising frequency upon mutations. We randomly mutated the previously generated leaky variants of LuxR, the quorum-sensing transcription activator from Vibrio fischeri, to restore the stringency. We found as much as 10-20% of the entire population exhibited significantly improved signal-to-noise ratios compared with their parents. This indicated that these mutants arose by the loss of folding capability by accumulating destabilizing mutations, not by introducing rare adaptive mutations, thereby becoming AHL-dependent folders. Only four rounds of mutagenesis and ON-state selection resulted in the domination of the entire population by the improved variants with low leak, without direct selection pressure for stringency. With this surprising frequency, conversion into the "ligand-addicted folders" should be one of the prevailing modes of evolving stringency both in the laboratory and in nature, and the workflow described here provides a rapid and versatile method of improving the signal-to-noise ratio of various genetic switches.
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Affiliation(s)
- Yuki Kimura
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33, Yayoi-Cho, Inage-ku, Chiba 263-8522, Japan
| | - Shigeko Kawai-Noma
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33, Yayoi-Cho, Inage-ku, Chiba 263-8522, Japan
| | - Kyoichi Saito
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33, Yayoi-Cho, Inage-ku, Chiba 263-8522, Japan
| | - Daisuke Umeno
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33, Yayoi-Cho, Inage-ku, Chiba 263-8522, Japan
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Woods KN, Pfeffer J. Conformational perturbation, allosteric modulation of cellular signaling pathways, and disease in P23H rhodopsin. Sci Rep 2020; 10:2657. [PMID: 32060349 PMCID: PMC7021821 DOI: 10.1038/s41598-020-59583-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 01/30/2020] [Indexed: 02/07/2023] Open
Abstract
In this investigation we use THz spectroscopy and MD simulation to study the functional dynamics and conformational stability of P23H rhodopsin. The P23H mutation of rod opsin is the most common cause of human binding autosomal dominant retinitis pigmentosa (ADRP), but the precise mechanism by which this mutation leads to photoreceptor cell degeneration has not yet been elucidated. Our measurements confirm conformational instability in the global modes of the receptor and an active-state that uncouples the torsional dynamics of the retinal with protein functional modes, indicating inefficient signaling in P23H and a drastically altered mechanism of activation when contrasted with the wild-type receptor. Further, our MD simulations indicate that P23H rhodopsin is not functional as a monomer but rather, due to the instability of the mutant receptor, preferentially adopts a specific homodimerization motif. The preferred homodimer configuration induces structural changes in the receptor tertiary structure that reduces the affinity of the receptor for the retinal and significantly modifies the interactions of the Meta-II signaling state. We conjecture that the formation of the specific dimerization motif of P23H rhodopsin represents a cellular-wide signaling perturbation that is directly tied with the mechanism of P23H disease pathogenesis. Our results also support a direct role for rhodopsin P23H dimerization in photoreceptor rod death.
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Affiliation(s)
- Kristina N Woods
- Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians-Universität, 80538, München, Germany.
| | - Jürgen Pfeffer
- Technical University of Munich, Bavarian School of Public Policy, 80333, München, Germany
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Ahmed CM, Dwyer BT, Romashko A, Van Adestine S, Park EH, Lou Z, Welty D, Josiah S, Savinainen A, Zhang B, Lewin AS. SRD005825 Acts as a Pharmacologic Chaperone of Opsin and Promotes Survival of Photoreceptors in an Animal Model of Autosomal Dominant Retinitis Pigmentosa. Transl Vis Sci Technol 2019; 8:30. [PMID: 31857914 PMCID: PMC6910612 DOI: 10.1167/tvst.8.6.30] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/11/2019] [Indexed: 01/17/2023] Open
Abstract
Purpose Mutations in RHO, the gene for a rhodopsin, are a leading cause of autosomal dominant retinitis pigmentosa. The objective of this study was to determine if a synthetic retinal analogue (SRD005825) serves as a pharmacologic chaperone to promote appropriate membrane trafficking of a mutant version of human rhodopsin. Methods A tetracycline-inducible cell line was used to produce human wild-type and T17M opsin. A cell-free assay was used to study the impact of SRD005825 on binding of 9-cis-retinal to wild-type opsin. A cell-based assay was used to measure the effect of SRD005825 on the generation of rhodopsin by spectroscopy and Western blot and the transport of rhodopsin to the cell membrane by confocal microscopy. Mice bearing T17M RHO were treated with daily oral doses of SRD005825, and retinal degeneration was measured by spectral-domain optical coherence tomography and, at the conclusion of the experiment, by electroretinography and morphometry. Results SRD005825 competed with 9-cis-retinal for binding to wild-type opsin but promoted the formation of rhodopsin in HEK293 cells and the trafficking of T17M rhodopsin to the plasma membrane of these cells. T17M transgenic mice exhibited rapid retinal degeneration, but thinning of the outer nuclear layer representative of photoreceptor cell bodies was delayed by treatment with SRD005825. Electroretinography a-wave and b-wave amplitudes were significantly improved by drug treatment. Conclusions SRD005825 promoted the reconstitution of mutant rhodopsin and its membrane localization. Because it delayed retinal degeneration in the mouse model, it has potential as a therapeutic for autosomal dominant retinitis pigmentosa. Translational Relevance SRD005825 may be useful as a treatment to delay retinal degeneration in retinitis pigmentosa patients with rhodopsin mutations causing misfolding of the protein.
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Affiliation(s)
- Chulbul M Ahmed
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Brian T Dwyer
- Shire HGT Inc., a member of the Takeda group of companies, Cambridge, MA, USA
| | - All Romashko
- Shire HGT Inc., a member of the Takeda group of companies, Cambridge, MA, USA
| | | | - Eun-He Park
- Shire HGT Inc., a member of the Takeda group of companies, Cambridge, MA, USA
| | - Zhe Lou
- Shire HGT Inc., a member of the Takeda group of companies, Cambridge, MA, USA
| | - Devi Welty
- Shire HGT Inc., a member of the Takeda group of companies, Cambridge, MA, USA
| | - Seren Josiah
- Shire HGT Inc., a member of the Takeda group of companies, Cambridge, MA, USA
| | - Annel Savinainen
- Shire HGT Inc., a member of the Takeda group of companies, Cambridge, MA, USA
| | - Bohon Zhang
- Shire HGT Inc., a member of the Takeda group of companies, Cambridge, MA, USA
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
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The Retinoid and Non-Retinoid Ligands of the Rod Visual G Protein-Coupled Receptor. Int J Mol Sci 2019; 20:ijms20246218. [PMID: 31835521 PMCID: PMC6941084 DOI: 10.3390/ijms20246218] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 11/27/2019] [Accepted: 12/06/2019] [Indexed: 02/06/2023] Open
Abstract
G protein-coupled receptors (GPCRs) play a predominant role in the drug discovery effort. These cell surface receptors are activated by a variety of specific ligands that bind to the orthosteric binding pocket located in the extracellular part of the receptor. In addition, the potential binding sites located on the surface of the receptor enable their allosteric modulation with critical consequences for their function and pharmacology. For decades, drug discovery focused on targeting the GPCR orthosteric binding sites. However, finding that GPCRs can be modulated allosterically opened a new venue for developing novel pharmacological modulators with higher specificity. Alternatively, focus on discovering of non-retinoid small molecules beneficial in retinopathies associated with mutations in rhodopsin is currently a fast-growing pharmacological field. In this review, we summarize the accumulated knowledge on retinoid ligands and non-retinoid modulators of the light-sensing GPCR, rhodopsin and their potential in combating the specific vision-related pathologies. Also, recent findings reporting the potential of biologically active compounds derived from natural products as potent rod opsin modulators with beneficial effects against degenerative diseases related to this receptor are highlighted here.
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Scott BM, Wybenga-Groot LE, McGlade CJ, Heon E, Peisajovich SG, Chang BSW. Screening of Chemical Libraries Using a Yeast Model of Retinal Disease. SLAS DISCOVERY 2019; 24:969-977. [PMID: 31556794 DOI: 10.1177/2472555219875934] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Retinitis pigmentosa (RP) is a degenerative retinal disease, often caused by mutations in the G-protein-coupled receptor rhodopsin. The majority of pathogenic rhodopsin mutations cause rhodopsin to misfold, including P23H, disrupting its crucial ability to respond to light. Previous screens to discover pharmacological chaperones of rhodopsin have primarily been based on rescuing rhodopsin trafficking and localization to the plasma membrane. Here, we present methods utilizing a yeast-based assay to screen for compounds that rescue the ability of rhodopsin to activate an associated downstream G-protein signaling cascade. We engineered a yeast strain in which human rhodopsin variants were genomically integrated, and were able to demonstrate functional coupling to the yeast mating pathway, leading to fluorescent protein expression. We confirmed that a known pharmacological chaperone, 9-cis retinal, could partially rescue light-dependent activation of a disease-associated rhodopsin mutation (P23H) expressed in yeast. These novel yeast strains were used to perform a phenotypic screen of 4280 compounds from the LOPAC1280 library and a peptidomimetic library, to discover novel pharmacological chaperones of rhodopsin. The fluorescence-based assay was robust in a 96-well format, with a Z' factor of 0.65 and a signal-to-background ratio of above 14. One compound was selected for additional analysis, but it did not appear to rescue rhodopsin function in yeast. The methods presented here are amenable to future screens of small-molecule libraries, as they are robust and cost-effective. We also discuss how these methods could be further modified or adapted to perform screens of more compounds in the future.
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Affiliation(s)
- Benjamin M Scott
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.,Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, USA.,Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | | | - C Jane McGlade
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.,Program in Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Elise Heon
- Department of Ophthalmology and Vision Science, The Hospital for Sick Children, Toronto, ON, Canada
| | - Sergio G Peisajovich
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Belinda S W Chang
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.,Centre for the Analysis of Genome Evolution and Function, University of Toronto, ON, Canada
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40
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Vázquez-Domínguez I, Garanto A, Collin RWJ. Molecular Therapies for Inherited Retinal Diseases-Current Standing, Opportunities and Challenges. Genes (Basel) 2019; 10:genes10090654. [PMID: 31466352 PMCID: PMC6770110 DOI: 10.3390/genes10090654] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/23/2019] [Accepted: 08/26/2019] [Indexed: 12/15/2022] Open
Abstract
Inherited retinal diseases (IRDs) are both genetically and clinically highly heterogeneous and have long been considered incurable. Following the successful development of a gene augmentation therapy for biallelic RPE65-associated IRD, this view has changed. As a result, many different therapeutic approaches are currently being developed, in particular a large variety of molecular therapies. These are depending on the severity of the retinal degeneration, knowledge of the pathophysiological mechanism underlying each subtype of IRD, and the therapeutic target molecule. DNA therapies include approaches such as gene augmentation therapy, genome editing and optogenetics. For some genetic subtypes of IRD, RNA therapies and compound therapies have also shown considerable therapeutic potential. In this review, we summarize the current state-of-the-art of various therapeutic approaches, including the pros and cons of each strategy, and outline the future challenges that lie ahead in the combat against IRDs.
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Affiliation(s)
- Irene Vázquez-Domínguez
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525GA Nijmegen, The Netherlands
| | - Alejandro Garanto
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525GA Nijmegen, The Netherlands.
| | - Rob W J Collin
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525GA Nijmegen, The Netherlands.
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41
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Qiu Y, Yao J, Jia L, Thompson DA, Zacks DN. Shifting the balance of autophagy and proteasome activation reduces proteotoxic cell death: a novel therapeutic approach for restoring photoreceptor homeostasis. Cell Death Dis 2019; 10:547. [PMID: 31320609 PMCID: PMC6639359 DOI: 10.1038/s41419-019-1780-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/26/2019] [Accepted: 06/27/2019] [Indexed: 12/13/2022]
Abstract
The P23H variant of rhodopsin results in misfolding of the protein, and is a common cause of the blinding disease autosomal dominant retinitis pigmentosa (adRP). We have recently demonstrated that degeneration of photoreceptor cells in retinas of P23H mice is due to the endoplasmic reticulum stress (ERS)-induced activation of autophagy that leads to a secondary proteasome insufficiency and activation of cell death pathways. We propose that this increased level of autophagy flux relative to proteasome activity, which we term the A:P ratio, represents a marker of altered photoreceptor cell homeostasis, and that therapies aimed at normalizing this ratio will result in increased photoreceptor cell survival. To test this postulate, we treated P23H mice with a chemical chaperone (4-phenylbutyric acid) to improve rhodopsin folding, or with a selective phosphodiesterase-4 inhibitor (rolipram) to increase proteasome activity. P23H mice treated with either of these agents exhibited reduced ERS, decreased autophagy flux, increased proteasome activity, and decreased activation of cell death pathways. In addition, rates of retinal degeneration were decreased, and photoreceptor morphology and visual function were preserved. These findings support the conclusion that normalizing the A:P ratio, either by reducing the ERS-induced activation of autophagy, or by increasing proteasome activity, improves photoreceptor survival, and suggest a potential new therapeutic strategy for the treatment of adRP caused by protein folding defects.
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Affiliation(s)
- Yaoyan Qiu
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, MI, USA.,Department of Ophthalmology, Xiangya School of medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jingyu Yao
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, MI, USA
| | - Lin Jia
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, MI, USA
| | - Debra A Thompson
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, MI, USA.,Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - David N Zacks
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, Ann Arbor, MI, USA.
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42
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Park PSH. Rhodopsin Oligomerization and Aggregation. J Membr Biol 2019; 252:413-423. [PMID: 31286171 DOI: 10.1007/s00232-019-00078-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/25/2019] [Indexed: 12/18/2022]
Abstract
Rhodopsin is the light receptor in photoreceptor cells of the retina and a prototypical G protein-coupled receptor. Two types of quaternary structures can be adopted by rhodopsin. If rhodopsin folds and attains a proper tertiary structure, it can then form oligomers and nanodomains within the photoreceptor cell membrane. In contrast, if rhodopsin misfolds, it cannot progress through the biosynthetic pathway and instead will form aggregates that can cause retinal degenerative disease. In this review, emerging views are highlighted on the supramolecular organization of rhodopsin within the membrane of photoreceptor cells and the aggregation of rhodopsin that can lead to retinal degeneration.
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Affiliation(s)
- Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
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43
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Wan A, Place E, Pierce EA, Comander J. Characterizing variants of unknown significance in rhodopsin: A functional genomics approach. Hum Mutat 2019; 40:1127-1144. [PMID: 30977563 PMCID: PMC7027811 DOI: 10.1002/humu.23762] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/31/2019] [Accepted: 04/08/2019] [Indexed: 01/19/2023]
Abstract
Characterizing the pathogenicity of DNA sequence variants of unknown significance (VUS) is a major bottleneck in human genetics, and is increasingly important in determining which patients with inherited retinal diseases could benefit from gene therapy. A library of 210 rhodopsin (RHO) variants from literature and in‐house genetic diagnostic testing were created to efficiently detect pathogenic RHO variants that fail to express on the cell surface. This study, while focused on RHO, demonstrates a streamlined, generalizable method for detecting pathogenic VUS. A relatively simple next‐generation sequencing‐based readout was developed so that a flow cytometry‐based assay could be performed simultaneously on all variants in a pooled format, without the need for barcodes or viral transduction. The resulting dataset characterized the surface expression of every RHO library variant with a high degree of reproducibility (r2 = 0.92–0.95), recategorizing 37 variants. For example, three retinitis pigmentosa pedigrees were solved by identifying VUS which showed low expression levels (p.G18D, p.G101V, and p.P180T). Results were validated across multiple assays and correlated with clinical disease severity. This study presents a parallelized, higher‐throughput cell‐based assay for the functional characterization of VUS in RHO, and can be applied more broadly to other inherited retinal disease genes and other disorders.
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Affiliation(s)
- Aliete Wan
- Department of Ophthalmology, Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Emily Place
- Department of Ophthalmology, Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Eric A Pierce
- Department of Ophthalmology, Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Jason Comander
- Department of Ophthalmology, Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
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44
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Genome Editing as a Treatment for the Most Prevalent Causative Genes of Autosomal Dominant Retinitis Pigmentosa. Int J Mol Sci 2019; 20:ijms20102542. [PMID: 31126147 PMCID: PMC6567127 DOI: 10.3390/ijms20102542] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/15/2019] [Accepted: 05/22/2019] [Indexed: 02/07/2023] Open
Abstract
: Inherited retinal dystrophies (IRDs) are a clinically and genetically heterogeneous group of diseases with more than 250 causative genes. The most common form is retinitis pigmentosa. IRDs lead to vision impairment for which there is no universal cure. Encouragingly, a first gene supplementation therapy has been approved for an autosomal recessive IRD. However, for autosomal dominant IRDs, gene supplementation therapy is not always pertinent because haploinsufficiency is not the only cause. Disease-causing mechanisms are often gain-of-function or dominant-negative, which usually require alternative therapeutic approaches. In such cases, genome-editing technology has raised hopes for treatment. Genome editing could be used to i) invalidate both alleles, followed by supplementation of the wild type gene, ii) specifically invalidate the mutant allele, with or without gene supplementation, or iii) to correct the mutant allele. We review here the most prevalent genes causing autosomal dominant retinitis pigmentosa and the most appropriate genome-editing strategy that could be used to target their different causative mutations.
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45
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Wen RH, Stanar P, Tam B, Moritz OL. Autophagy in Xenopus laevis rod photoreceptors is independently regulated by phototransduction and misfolded RHO P23H. Autophagy 2019; 15:1970-1989. [PMID: 30975014 DOI: 10.1080/15548627.2019.1596487] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We previously reported autophagic structures in rod photoreceptors expressing a misfolding RHO (rhodopsin) mutant (RHOP23H), suggesting that autophagy may play a role in degrading the mutant RHO and/or be involved in photoreceptor cell death. To further examine autophagy in normal and diseased rods, we generated transgenic Xenopus laevis tadpoles expressing the dually fluorescent autophagy marker mRFP-eGFP-LC3 in rods, which changes from green to yellow and finally red as autophagic structures develop and mature. Using transgenic lines with constitutive and inducible expression, we determined the time-course of autophagy in rod photoreceptors: autophagosomes last for 6 to 8 hours before fusing with lysosomes, and acidified autolysosomes last for about 28 hours before being degraded. Autophagy was diurnally regulated in normal rods, with more autophagic structures generated during periods of light, and this regulation was non-circadian. We also found that more autophagosomes were produced in rods expressing the misfolding RHOP23H mutant. The RHO chromophore absorbs photons to initiate phototransduction, and is consumed in this process; it also promotes RHO folding. To determine whether increased autophagy in light-exposed normal rods is caused by increased RHO misfolding or phototransduction, we used CRISPR/Cas9 to knock out the RPE65 and GNAT1 genes, which are essential for chromophore biosynthesis and phototransduction respectively. Both knockouts suppressed light-induced autophagy, indicating that although light and misfolded rhodopsin can both induce autophagy in rods, light-induced autophagy is not due to misfolding of RHO, but rather due to phototransduction. Abbreviations: CYCS: cytochrome c; bRHOP23H: bovine RHOP23H; Cas9: CRISPR associated protein 9; dpf: days post-fertilization; eGFP: enhanced green fluorescent protein; GNAT1: guanine nucleotide-binding protein G(t) subunit alpha-1 aka rod alpha-transducin; HSPA1A/hsp70: heat shock protein of 70 kilodaltons; LAMP1: lysosomal-associated membrane protein 1; LC3: microtubule-associated protein 1A/1B light chain 3; mRFP: monomeric red fluorescent protein; RHO: rhodopsin; RP: retinitis pigmentosa; RPE65: retinal pigment epithelium-specific 65 kDa protein: sfGFP: superfolding GFP; sgRNA: single guide RNA; WGA: wheat germ agglutinin; RHOp: the Xenopus laevis RHO.2.L promoter.
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Affiliation(s)
- Runxia H Wen
- Department of Ophthalmology and Visual Sciences, University of British Columbia , Vancouver , British Columbia , Canada
| | - Paloma Stanar
- Department of Ophthalmology and Visual Sciences, University of British Columbia , Vancouver , British Columbia , Canada
| | - Beatrice Tam
- Department of Ophthalmology and Visual Sciences, University of British Columbia , Vancouver , British Columbia , Canada
| | - Orson L Moritz
- Department of Ophthalmology and Visual Sciences, University of British Columbia , Vancouver , British Columbia , Canada
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46
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Wang W, Guo DY, Tao YX. Therapeutic strategies for diseases caused by loss-of-function mutations in G protein-coupled receptors. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 161:181-210. [DOI: 10.1016/bs.pmbts.2018.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Gragg M, Park PSH. Misfolded rhodopsin mutants display variable aggregation properties. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2938-2948. [PMID: 29890221 PMCID: PMC6066411 DOI: 10.1016/j.bbadis.2018.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/31/2018] [Accepted: 06/06/2018] [Indexed: 11/20/2022]
Abstract
The largest class of rhodopsin mutations causing autosomal dominant retinitis pigmentosa (adRP) is mutations that lead to misfolding and aggregation of the receptor. The misfolding mutants have been characterized biochemically, and categorized as either partial or complete misfolding mutants. This classification is incomplete and does not provide sufficient information to fully understand the disease pathogenesis and evaluate therapeutic strategies. A Förster resonance energy transfer (FRET) method was utilized to directly assess the aggregation properties of misfolding rhodopsin mutants within the cell. Partial (P23H and P267L) and complete (G188R, H211P, and P267R) misfolding mutants were characterized to reveal variability in aggregation properties. The complete misfolding mutants all behaved similarly, forming aggregates when expressed alone, minimally interacting with the wild-type receptor when coexpressed, and were unresponsive to treatment with the pharmacological chaperone 9-cis retinal. In contrast, variability was observed between the partial misfolding mutants. In the opsin form, the P23H mutant behaved similarly as the complete misfolding mutants. In contrast, the opsin form of the P267L mutant existed as both aggregates and oligomers when expressed alone and formed mostly oligomers with the wild-type receptor when coexpressed. The partial misfolding mutants both reacted similarly to the pharmacological chaperone 9-cis retinal, displaying improved folding and oligomerization when expressed alone but aggregating with wild-type receptor when coexpressed. The observed differences in aggregation properties and effect of 9-cis retinal predict different outcomes in disease pathophysiology and suggest that retinoid-based chaperones will be ineffective or even detrimental.
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Affiliation(s)
- Megan Gragg
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA.
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48
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Yao J, Qiu Y, Frontera E, Jia L, Khan NW, Klionsky DJ, Ferguson TA, Thompson DA, Zacks DN. Inhibiting autophagy reduces retinal degeneration caused by protein misfolding. Autophagy 2018; 14:1226-1238. [PMID: 29940785 PMCID: PMC6103695 DOI: 10.1080/15548627.2018.1463121] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 04/02/2018] [Accepted: 04/04/2018] [Indexed: 12/13/2022] Open
Abstract
Mutations in the genes necessary for the structure and function of vertebrate photoreceptor cells are associated with multiple forms of inherited retinal degeneration. Mutations in the gene encoding RHO (rhodopsin) are a common cause of autosomal dominant retinitis pigmentosa (adRP), with the Pro23His variant of RHO resulting in a misfolded protein that activates endoplasmic reticulum stress and the unfolded protein response. Stimulating macroautophagy/autophagy has been proposed as a strategy for clearing misfolded RHO and reducing photoreceptor death. We found that retinas from mice heterozygous for the gene encoding the RHOP23H variant (hereafter called P23H) exhibited elevated levels of autophagy flux, and that pharmacological stimulation of autophagy accelerated retinal degeneration. In contrast, reducing autophagy flux pharmacologically or by rod-specific deletion of the autophagy-activating gene Atg5, improved photoreceptor structure and function. Furthermore, proteasome levels and activity were reduced in the P23H retina, and increased when Atg5 was deleted. Our findings suggest that autophagy contributes to photoreceptor cell death in P23H mice, and that decreasing autophagy shifts the degradation of misfolded RHO protein to the proteasome and is protective. These observations suggest that modulating the flux of misfolded proteins from autophagy to the proteasome may represent an important therapeutic strategy for reducing proteotoxicity in adRP and other diseases caused by protein folding defects.
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Affiliation(s)
- Jingyu Yao
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Yaoyan Qiu
- Department of Ophthalmology, Xiangya School of medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Eric Frontera
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Lin Jia
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Naheed W. Khan
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
| | | | - Thomas A. Ferguson
- Department of Ophthalmology and Visual Sciences, Washington University, St. Louis, MO, USA
| | - Debra A. Thompson
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - David N. Zacks
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
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49
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Kumaran N, Michaelides M, Smith AJ, Ali RR, Bainbridge JWB. Retinal gene therapy. Br Med Bull 2018; 126:13-25. [PMID: 29506236 DOI: 10.1093/bmb/ldy005] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 02/12/2018] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Inherited retinal diseases are the leading cause of sight impairment in people of working age in England and Wales, and the second commonest in childhood. Gene therapy offers the potential for benefit. SOURCES OF DATA Pubmed and clinicaltrials.gov. AREAS OF AGREEMENT Gene therapy can improve vision in RPE65-associated Leber Congenital Amaurosis (RPE65-LCA). Potential benefit depends on efficient gene transfer and is limited by the extent of retinal degeneration. AREAS OF CONTROVERSY The magnitude of vision improvement from RPE65-LCA gene therapy is suboptimal, and its durability may be limited by progressive retinal degeneration. GROWING POINTS The safety and potential benefit of gene therapy for inherited and acquired retinal diseases is being explored in a rapidly expanding number of trials. AREAS TIMELY FOR DEVELOPING RESEARCH Developments in vector design and delivery will enable greater efficiency and safety of gene transfer. Optimization of trial design will accelerate reliable assessment of outcomes.
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Affiliation(s)
- Neruban Kumaran
- NIHR Biomedical Research Centre for Ophthalmology at Moofields Eye Hospital and UCL, 162 City Road, London, UK
| | - Michel Michaelides
- NIHR Biomedical Research Centre for Ophthalmology at Moofields Eye Hospital and UCL, 162 City Road, London, UK
| | - Alexander J Smith
- NIHR Biomedical Research Centre for Ophthalmology at Moofields Eye Hospital and UCL, 162 City Road, London, UK
| | - Robin R Ali
- NIHR Biomedical Research Centre for Ophthalmology at Moofields Eye Hospital and UCL, 162 City Road, London, UK
| | - James W B Bainbridge
- NIHR Biomedical Research Centre for Ophthalmology at Moofields Eye Hospital and UCL, 162 City Road, London, UK
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Behnen P, Felline A, Comitato A, Di Salvo MT, Raimondi F, Gulati S, Kahremany S, Palczewski K, Marigo V, Fanelli F. A Small Chaperone Improves Folding and Routing of Rhodopsin Mutants Linked to Inherited Blindness. iScience 2018; 4:1-19. [PMID: 30240733 PMCID: PMC6147235 DOI: 10.1016/j.isci.2018.05.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 04/06/2018] [Accepted: 04/30/2018] [Indexed: 11/24/2022] Open
Abstract
The autosomal dominant form of retinitis pigmentosa (adRP) is a blindness-causing conformational disease largely linked to mutations of rhodopsin. Molecular simulations coupled to the graph-based protein structure network (PSN) analysis and in vitro experiments were conducted to determine the effects of 33 adRP rhodopsin mutations on the structure and routing of the opsin protein. The integration of atomic and subcellular levels of analysis was accomplished by the linear correlation between indices of mutational impairment in structure network and in routing. The graph-based index of structural perturbation served also to divide the mutants in four clusters, consistent with their differences in subcellular localization and responses to 9-cis retinal. The stability core of opsin inferred from PSN analysis was targeted by virtual screening of over 300,000 anionic compounds leading to the discovery of a reversible orthosteric inhibitor of retinal binding more effective than retinal in improving routing of three adRP mutants. In silico and in vitro analyses of adRP rhodopsin mutants bridged folding and routing Structure network analysis grouped mutants amenable to treatment with small chaperones Virtual compound screening against the stability core of opsin found a small chaperone The pharmacoperone is a reversible orthosteric inhibitor of retinal binding
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Affiliation(s)
- Petra Behnen
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Angelo Felline
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy
| | - Antonella Comitato
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Maria Teresa Di Salvo
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Francesco Raimondi
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy
| | - Sahil Gulati
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 East 101st Street, Cleveland, OH 44106, USA
| | - Shirin Kahremany
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 East 101st Street, Cleveland, OH 44106, USA
| | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy; Center for Neuroscience and Neurotechnology, via Campi 287, 41125 Modena, Italy.
| | - Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy; Center for Neuroscience and Neurotechnology, via Campi 287, 41125 Modena, Italy.
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