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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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Molecular Basis for Variations in the Sensitivity of Pathogenic Rhodopsin Variants to 9-cis-Retinal. J Biol Chem 2022; 298:102266. [PMID: 35850308 PMCID: PMC9399271 DOI: 10.1016/j.jbc.2022.102266] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 11/24/2022] Open
Abstract
Over 100 mutations in the rhodopsin gene have been linked to a spectrum of retinopathies that include retinitis pigmentosa and congenital stationary night blindness. Though most of these variants exhibit a loss of function, the molecular defects caused by these underlying mutations vary considerably. In this work, we utilize deep mutational scanning to quantitatively compare the plasma membrane expression of 123 known pathogenic rhodopsin variants in the presence and absence of the stabilizing cofactor 9-cis-retinal. We identify 69 retinopathy variants, including 20 previously uncharacterized variants, that exhibit diminished plasma membrane expression in HEK293T cells. Of these apparent class II variants, 67 exhibit a measurable increase in expression in the presence of 9-cis-retinal. However, the magnitude of the response to this molecule varies considerably across this spectrum of mutations. Evaluation of the observed shifts relative to thermodynamic estimates for the coupling between binding and folding suggests underlying differences in stability constrains the magnitude of their response to retinal. Nevertheless, estimates from computational modeling suggest that many of the least sensitive variants also directly compromise binding. Finally, we evaluate the functional properties of three previous uncharacterized, retinal-sensitive variants (ΔN73, S131P, and R135G) and show that two of these retain residual function in vitro. Together, our results provide a comprehensive experimental characterization of the proteostatic properties of retinopathy variants and their response to retinal.
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3
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Effects of Epigenetic Modification of PGC-1α by a Chemical Chaperon on Mitochondria Biogenesis and Visual Function in Retinitis Pigmentosa. Cells 2022; 11:cells11091497. [PMID: 35563803 PMCID: PMC9099608 DOI: 10.3390/cells11091497] [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] [Received: 02/14/2022] [Revised: 04/13/2022] [Accepted: 04/27/2022] [Indexed: 11/17/2022] Open
Abstract
Retinitis pigmentosa (RP) is a hereditary blinding disease characterized by gradual photoreceptor death, which lacks a definitive treatment. Here, we demonstrated the effect of 4-phenylbutyric acid (PBA), a chemical chaperon that can suppress endoplasmic reticulum (ER) stress, in P23H mutant rhodopsin knock-in RP models. In the RP models, constant PBA treatment led to the retention of a greater number of photoreceptors, preserving the inner segment (IS), a mitochondrial- and ER-rich part of the photoreceptors. Electroretinography showed that PBA treatment preserved photoreceptor function. At the early point, ER-associated degradation markers, xbp1s, vcp, and derl1, mitochondrial kinetic-related markers, fis1, lc3, and mfn1 and mfn2, as well as key mitochondrial regulators, pgc-1α and tfam, were upregulated in the retina of the models treated with PBA. In vitro analyses showed that PBA upregulated pgc-1α and tfam transcription, leading to an increase in the mitochondrial membrane potential, cytochrome c oxidase activity, and ATP levels. Histone acetylation of the PGC-1α promoter was increased by PBA, indicating that PBA affected the mitochondrial condition through epigenetic changes. Our findings constituted proof of concept for the treatment of ER stress-related RP using PBA and revealed PBA’s neuroprotective effects, paving the way for its future clinical application.
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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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5
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Pasqualetto G, Pileggi E, Schepelmann M, Varricchio C, Rozanowska M, Brancale A, Bassetto M. Ligand-based rational design, synthesis and evaluation of novel potential chemical chaperones for opsin. Eur J Med Chem 2021; 226:113841. [PMID: 34555613 DOI: 10.1016/j.ejmech.2021.113841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/07/2021] [Accepted: 09/07/2021] [Indexed: 12/01/2022]
Abstract
Inherited blinding diseases retinitis pigmentosa (RP) and a subset of Leber's congenital amaurosis (LCA) are caused by the misfolding and mistrafficking of rhodopsin molecules, which aggregate and accumulate in the endoplasmic reticulum (ER), leading to photoreceptor cell death. One potential therapeutic strategy to prevent the loss of photoreceptors in these conditions is to identify opsin-binding compounds that act as chemical chaperones for opsin, aiding its proper folding and trafficking to the outer cell membrane. Aiming to identify novel compounds with such effect, a rational ligand-based approach was applied to the structure of the visual pigment chromophore, 11-cis-retinal, and its locked analogue 11-cis-6mr-retinal. Following molecular docking studies on the main chromophore binding site of rhodopsin, 49 novel compounds were synthesized according to optimized one-to seven-step synthetic routes. These agents were evaluated for their ability to compete for the chromophore binding site of opsin, and their capacity to increase the trafficking of the P23H opsin mutant from the ER to the cell membrane. Different new molecules displayed an effect in at least one assay, acting either as chemical chaperones or as stabilizers of the 9-cis-retinal-rhodopsin complex. These compounds could provide the basis to develop novel therapeutics for RP and LCA.
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Affiliation(s)
- Gaia Pasqualetto
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, CF10 3NB, UK
| | - Elisa Pileggi
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, CF10 3NB, UK
| | - Martin Schepelmann
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, 1090, Austria; School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, UK
| | - Carmine Varricchio
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, CF10 3NB, UK
| | - Malgorzata Rozanowska
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, UK; Cardiff Institute for Tissue Engineering and Repair (CITER), Cardiff University, Cardiff, CF10 3NB, UK
| | - Andrea Brancale
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, CF10 3NB, UK
| | - Marcella Bassetto
- Department of Chemistry, Faculty of Science and Engineering, Swansea University, Swansea, SA2 8PP, UK.
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Patrizi C, Llado M, Benati D, Iodice C, Marrocco E, Guarascio R, Surace EM, Cheetham ME, Auricchio A, Recchia A. Allele-specific editing ameliorates dominant retinitis pigmentosa in a transgenic mouse model. Am J Hum Genet 2021; 108:295-308. [PMID: 33508235 PMCID: PMC7896132 DOI: 10.1016/j.ajhg.2021.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/08/2021] [Indexed: 12/11/2022] Open
Abstract
Retinitis pigmentosa (RP) is a group of progressive retinal degenerations of mostly monogenic inheritance, which cause blindness in about 1:3,500 individuals worldwide. Heterozygous variants in the rhodopsin (RHO) gene are the most common cause of autosomal dominant RP (adRP). Among these, missense variants at C-terminal proline 347, such as p.Pro347Ser, cause severe adRP recurrently in European affected individuals. Here, for the first time, we use CRISPR/Cas9 to selectively target the p.Pro347Ser variant while preserving the wild-type RHO allele in vitro and in a mouse model of adRP. Detailed in vitro, genomic, and biochemical characterization of the rhodopsin C-terminal editing demonstrates a safe downregulation of p.Pro347Ser expression leading to partial recovery of photoreceptor function in a transgenic mouse model treated with adeno-associated viral vectors. This study supports the safety and efficacy of CRISPR/Cas9-mediated allele-specific editing and paves the way for a permanent and precise correction of heterozygous variants in dominantly inherited retinal diseases.
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Affiliation(s)
- Clarissa Patrizi
- Centre for Regenerative Medicine, Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Manel Llado
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Daniela Benati
- Centre for Regenerative Medicine, Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Carolina Iodice
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Elena Marrocco
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | | | - Enrico M Surace
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy; Medical Genetics, Department of Translational Medicine, Federico II University, 80125 Naples, Italy
| | | | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy; Medical Genetics, Department of Advanced Biomedicine, Federico II University, 80125 Naples, Italy.
| | - Alessandra Recchia
- Centre for Regenerative Medicine, Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.
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7
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Pasqualetto G, Schepelmann M, Varricchio C, Pileggi E, Khogali C, Morgan SR, Boostrom I, Rozanowska M, Brancale A, Ferla S, Bassetto M. Computational Studies towards the Identification of Novel Rhodopsin-Binding Compounds as Chemical Chaperones for Misfolded Opsins. Molecules 2020; 25:molecules25214904. [PMID: 33114011 PMCID: PMC7660337 DOI: 10.3390/molecules25214904] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 01/19/2023] Open
Abstract
Accumulation of misfolded and mistrafficked rhodopsin on the endoplasmic reticulum of photoreceptor cells has a pivotal role in the pathogenesis of retinitis pigmentosa and a subset of Leber’s congenital amaurosis. One potential strategy to reduce rhodopsin misfolding and aggregation in these conditions is to use opsin-binding compounds as chemical chaperones for opsin. Such molecules have previously shown the ability to aid rhodopsin folding and proper trafficking to the outer cell membranes of photoreceptors. As means to identify novel chemical chaperones for rhodopsin, a structure-based virtual screening of commercially available drug-like compounds (300,000) was performed on the main binding site of the visual pigment chromophore, the 11-cis-retinal. The best 24 virtual hits were examined for their ability to compete for the chromophore-binding site of opsin. Among these, four small molecules demonstrated the ability to reduce the rate constant for the formation of the 9-cis-retinal-rhodopsin complex, while five molecules surprisingly enhanced the formation of this complex. Compound 7, 13, 20 and 23 showed a weak but detectable increase in the trafficking of the P23H mutant, widely used as a model for both retinitis pigmentosa and Leber’s congenital amaurosis, from the ER to the cell membrane. The compounds did not show any relevant cytotoxicity in two different human cell lines, with the only exception of 13. Based on the structures of these active compounds, a series of in silico studies gave important insights on the potential structural features required for a molecule to act either as chemical chaperone or as stabiliser of the 11-cis-retinal-rhodopsin complex. Thus, this study revealed a series of small molecules that represent a solid foundation for the future development of novel therapeutics against these severe inherited blinding diseases.
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Affiliation(s)
- Gaia Pasqualetto
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK; (G.P.); (C.V.); (E.P.)
| | - Martin Schepelmann
- Institute of Pathophysiology and Allergy Research, Medical University of Vienna, 1090 Vienna, Austria;
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, UK; (C.K.); (S.R.M.); (I.B.); (M.R.)
| | - Carmine Varricchio
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK; (G.P.); (C.V.); (E.P.)
| | - Elisa Pileggi
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK; (G.P.); (C.V.); (E.P.)
| | - Caroline Khogali
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, UK; (C.K.); (S.R.M.); (I.B.); (M.R.)
| | - Siân R. Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, UK; (C.K.); (S.R.M.); (I.B.); (M.R.)
- Cardiff Institute for Tissue Engineering and Repair (CITER), Cardiff University, Cardiff CF10 3NB, UK
| | - Ian Boostrom
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, UK; (C.K.); (S.R.M.); (I.B.); (M.R.)
| | - Malgorzata Rozanowska
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4HQ, UK; (C.K.); (S.R.M.); (I.B.); (M.R.)
- Cardiff Institute for Tissue Engineering and Repair (CITER), Cardiff University, Cardiff CF10 3NB, UK
| | - Andrea Brancale
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK; (G.P.); (C.V.); (E.P.)
- Correspondence:
| | - Salvatore Ferla
- Swansea University Medical School, Institute of Life Sciences 2, Swansea University, Swansea SA2 8PP, UK;
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Terui R, Yanase Y, Yokoo H, Suhara Y, Makishima M, Demizu Y, Misawa T. Development of Selective TGR5 Ligands Based on the 5,6,7,8-Tetrahydro-5,5,8,8-tetramethylnaphthalene Skeleton. ChemMedChem 2020; 16:458-462. [PMID: 32969181 DOI: 10.1002/cmdc.202000567] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/24/2020] [Indexed: 01/05/2023]
Abstract
TGR5, a G-protein-coupled receptor (GPCR), plays an important role in several physiological functions. TGR5 activation through bile acids induces an increase in energy expenditure. Therefore, synthetic TGR5 ligands could be useful for the treatment of obesity or dyslipidemia. In this study, we designed and synthesized a set of TGR5 ligands with a 5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphthalene (TMN) skeleton, and evaluated their TGR5 agonistic activity. We also investigated the selectivity of the synthesized compounds for TGR5 relative to the farnesoid X receptor (FXR) and retinoic acid receptor (RAR). Our results show that compound 4 b [N-(2-chlorophenyl)-5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenecarboxamide] exhibited potent TGR5 agonist activity with an IC50 value of 8.4 nM without significant cytotoxicity. In addition, compound 4 b showed only slight agonistic activity toward FXR and RAR at 1 μM treatment. These data indicate that compound 4 b is a selective TGR5 agonist, and could be a promising therapeutic agent for dyslipidemia.
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Affiliation(s)
- Ryusei Terui
- National Institute of Health Sciences, 1 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
- Faculty of Bioscience and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama-shi, Saitama, 337-8570, Japan
| | - Yuta Yanase
- National Institute of Health Sciences, 1 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Yokohama, Kanagawa, 230-0045, Japan
| | - Hidetomo Yokoo
- National Institute of Health Sciences, 1 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Yoshitomo Suhara
- Faculty of Bioscience and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama-shi, Saitama, 337-8570, Japan
| | - Makoto Makishima
- Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo, 173-8610, Japan
| | - Yosuke Demizu
- National Institute of Health Sciences, 1 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Yokohama, Kanagawa, 230-0045, Japan
| | - Takashi Misawa
- National Institute of Health Sciences, 1 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
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Comitato A, Schiroli D, Montanari M, Marigo V. Calpain Activation Is the Major Cause of Cell Death in Photoreceptors Expressing a Rhodopsin Misfolding Mutation. Mol Neurobiol 2019; 57:589-599. [PMID: 31401765 DOI: 10.1007/s12035-019-01723-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 07/26/2019] [Indexed: 10/26/2022]
Abstract
The majority of mutations in rhodopsin (RHO) cause misfolding of the protein and has been linked to degeneration of photoreceptor cells in the retina. A lot of attention has been set on targeting ER stress for the development of new therapies for inherited retinal degeneration caused by mutations in the RHO gene. Nevertheless, the cell death pathway activated by RHO misfolded protein is still debated. In this study, we analyzed the retina of the knock-in mouse expressing the P23H misfolded mutant RHO. We found persistent unfolded protein response (UPR) during degeneration. Interestingly, long-term stimulation of the PERK branch of ER stress had a protective effect by phosphorylating nuclear factor erythroid 2-related factor 2 (NRF2) transcription factor, associated with antioxidant responses. Otherwise, we provide evidence that increased intracellular calcium and activation of calpains strongly correlated with rod photoreceptor cell death. By blocking calpain activity, we significantly decreased the activation of caspase-7 and apoptosis-inducing factor (AIF), two cell death effectors, and cell demise, and effectively protected the retina from degeneration caused by the P23H dominant mutation in RHO.
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Affiliation(s)
- Antonella Comitato
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi, 287, 41125, Modena, Italy
| | - Davide Schiroli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi, 287, 41125, Modena, Italy
| | - Monica Montanari
- 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.
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Marinko J, Huang H, Penn WD, Capra JA, Schlebach JP, Sanders CR. Folding and Misfolding of Human Membrane Proteins in Health and Disease: From Single Molecules to Cellular Proteostasis. Chem Rev 2019; 119:5537-5606. [PMID: 30608666 PMCID: PMC6506414 DOI: 10.1021/acs.chemrev.8b00532] [Citation(s) in RCA: 160] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Indexed: 12/13/2022]
Abstract
Advances over the past 25 years have revealed much about how the structural properties of membranes and associated proteins are linked to the thermodynamics and kinetics of membrane protein (MP) folding. At the same time biochemical progress has outlined how cellular proteostasis networks mediate MP folding and manage misfolding in the cell. When combined with results from genomic sequencing, these studies have established paradigms for how MP folding and misfolding are linked to the molecular etiologies of a variety of diseases. This emerging framework has paved the way for the development of a new class of small molecule "pharmacological chaperones" that bind to and stabilize misfolded MP variants, some of which are now in clinical use. In this review, we comprehensively outline current perspectives on the folding and misfolding of integral MPs as well as the mechanisms of cellular MP quality control. Based on these perspectives, we highlight new opportunities for innovations that bridge our molecular understanding of the energetics of MP folding with the nuanced complexity of biological systems. Given the many linkages between MP misfolding and human disease, we also examine some of the exciting opportunities to leverage these advances to address emerging challenges in the development of therapeutics and precision medicine.
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Affiliation(s)
- Justin
T. Marinko
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Wesley D. Penn
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - John A. Capra
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37245, United States
| | - Jonathan P. Schlebach
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
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11
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Ortega JT, Parmar T, Jastrzebska B. Flavonoids enhance rod opsin stability, folding, and self-association by directly binding to ligand-free opsin and modulating its conformation. J Biol Chem 2019; 294:8101-8122. [PMID: 30944172 DOI: 10.1074/jbc.ra119.007808] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/27/2019] [Indexed: 12/29/2022] Open
Abstract
Rhodopsin (Rho) is a visual G protein-coupled receptor expressed in the rod photoreceptors of the eye, where it mediates transmission of a light signal into a cell and converts this signal into a nerve impulse. More than 100 mutations in Rho are linked to various ocular impairments, including retinitis pigmentosa (RP). Accordingly, much effort has been directed toward developing ligands that target Rho and improve its folding and stability. Natural compounds may provide another viable approach to such drug discovery efforts. The dietary polyphenol compounds, ubiquitously present in fruits and vegetables, have beneficial effects in several eye diseases. However, the underlying mechanism of their activity is not fully understood. In this study, we used a combination of computational methods, biochemical and biophysical approaches, including bioluminescence resonance energy transfer, and mammalian cell expression systems to clarify the effects of four common bioactive flavonoids (quercetin, myricetin, and their mono-glycosylated forms quercetin-3-rhamnoside and myricetrin) on rod opsin stability, function, and membrane organization. We observed that by directly interacting with ligand-free opsin, flavonoids modulate its conformation, thereby causing faster entry of the retinal chromophore into its binding pocket. Moreover, flavonoids significantly increased opsin stability, most likely by introducing structural rigidity and promoting receptor self-association within the biological membranes. Of note, the binding of flavonoids to an RP-linked P23H opsin variant partially restored its normal cellular trafficking. Together, our results suggest that flavonoids could be utilized as lead compounds in the development of effective nonretinoid therapeutics for managing RP-related retinopathies.
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Affiliation(s)
- Joseph T Ortega
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Tanu Parmar
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Beata Jastrzebska
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
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12
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Chen Y, Chen Y, Jastrzebska B, Golczak M, Gulati S, Tang H, Seibel W, Li X, Jin H, Han Y, Gao S, Zhang J, Liu X, Heidari-Torkabadi H, Stewart PL, Harte WE, Tochtrop GP, Palczewski K. A novel small molecule chaperone of rod opsin and its potential therapy for retinal degeneration. Nat Commun 2018; 9:1976. [PMID: 29773803 PMCID: PMC5958115 DOI: 10.1038/s41467-018-04261-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 04/13/2018] [Indexed: 12/21/2022] Open
Abstract
Rhodopsin homeostasis is tightly coupled to rod photoreceptor cell survival and vision. Mutations resulting in the misfolding of rhodopsin can lead to autosomal dominant retinitis pigmentosa (adRP), a progressive retinal degeneration that currently is untreatable. Using a cell-based high-throughput screen (HTS) to identify small molecules that can stabilize the P23H-opsin mutant, which causes most cases of adRP, we identified a novel pharmacological chaperone of rod photoreceptor opsin, YC-001. As a non-retinoid molecule, YC-001 demonstrates micromolar potency and efficacy greater than 9-cis-retinal with lower cytotoxicity. YC-001 binds to bovine rod opsin with an EC50 similar to 9-cis-retinal. The chaperone activity of YC-001 is evidenced by its ability to rescue the transport of multiple rod opsin mutants in mammalian cells. YC-001 is also an inverse agonist that non-competitively antagonizes rod opsin signaling. Significantly, a single dose of YC-001 protects Abca4 -/- Rdh8 -/- mice from bright light-induced retinal degeneration, suggesting its broad therapeutic potential.
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Affiliation(s)
- Yuanyuan Chen
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- The McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive Suite 300, Pittsburgh, PA, 15219, USA.
- Department of Ophthalmology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA, 15260, USA.
| | - Yu Chen
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Yueyang Hospital and Clinical Research Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, 200437, Shanghai, China
| | - Beata Jastrzebska
- 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 E. 101st Street, Cleveland, OH, 44106, USA
| | - Marcin Golczak
- 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 E. 101st Street, Cleveland, OH, 44106, USA
| | - 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 E. 101st Street, Cleveland, OH, 44106, USA
| | - Hong Tang
- Drug Discovery Center, University of Cincinnati, 2180 E. Galbraith Road, Cincinnati, OH, 45237, USA
| | - William Seibel
- Drug Discovery Center, University of Cincinnati, 2180 E. Galbraith Road, Cincinnati, OH, 45237, USA
| | - Xiaoyu Li
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Hui Jin
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Yong Han
- Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Songqi Gao
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Jianye Zhang
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Xujie Liu
- Department of Ophthalmology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA, 15260, USA
| | - Hossein Heidari-Torkabadi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Phoebe L Stewart
- 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 E. 101st Street, Cleveland, OH, 44106, USA
| | - William E Harte
- Office of Translation and Innovation, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Gregory P Tochtrop
- Department of Chemistry, 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 E. 101st Street, Cleveland, OH, 44106, USA.
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13
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Mattle D, Kuhn B, Aebi J, Bedoucha M, Kekilli D, Grozinger N, Alker A, Rudolph MG, Schmid G, Schertler GFX, Hennig M, Standfuss J, Dawson RJP. Ligand channel in pharmacologically stabilized rhodopsin. Proc Natl Acad Sci U S A 2018; 115:3640-3645. [PMID: 29555765 PMCID: PMC5889642 DOI: 10.1073/pnas.1718084115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In the degenerative eye disease retinitis pigmentosa (RP), protein misfolding leads to fatal consequences for cell metabolism and rod and cone cell survival. To stop disease progression, a therapeutic approach focuses on stabilizing inherited protein mutants of the G protein-coupled receptor (GPCR) rhodopsin using pharmacological chaperones (PC) that improve receptor folding and trafficking. In this study, we discovered stabilizing nonretinal small molecules by virtual and thermofluor screening and determined the crystal structure of pharmacologically stabilized opsin at 2.4 Å resolution using one of the stabilizing hits (S-RS1). Chemical modification of S-RS1 and further structural analysis revealed the core binding motif of this class of rhodopsin stabilizers bound at the orthosteric binding site. Furthermore, previously unobserved conformational changes are visible at the intradiscal side of the seven-transmembrane helix bundle. A hallmark of this conformation is an open channel connecting the ligand binding site with the membrane and the intradiscal lumen of rod outer segments. Sufficient in size, the passage permits the exchange of hydrophobic ligands such as retinal. The results broaden our understanding of rhodopsin's conformational flexibility and enable therapeutic drug intervention against rhodopsin-related retinitis pigmentosa.
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Affiliation(s)
- Daniel Mattle
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Bernd Kuhn
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Johannes Aebi
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Marc Bedoucha
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Demet Kekilli
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Nathalie Grozinger
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Andre Alker
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Markus G Rudolph
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Georg Schmid
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Gebhard F X Schertler
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Michael Hennig
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland
| | - Jörg Standfuss
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland;
| | - Roger J P Dawson
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, 4070 Basel, Switzerland;
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14
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Athanasiou D, Aguila M, Opefi CA, South K, Bellingham J, Bevilacqua D, Munro PM, Kanuga N, Mackenzie FE, Dubis AM, Georgiadis A, Graca AB, Pearson RA, Ali RR, Sakami S, Palczewski K, Sherman MY, Reeves PJ, Cheetham ME. Rescue of mutant rhodopsin traffic by metformin-induced AMPK activation accelerates photoreceptor degeneration. Hum Mol Genet 2017; 26:305-319. [PMID: 28065882 PMCID: PMC5351934 DOI: 10.1093/hmg/ddw387] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 11/04/2016] [Accepted: 11/05/2016] [Indexed: 01/29/2023] Open
Abstract
Protein misfolding caused by inherited mutations leads to loss of protein function and potentially toxic 'gain of function', such as the dominant P23H rhodopsin mutation that causes retinitis pigmentosa (RP). Here, we tested whether the AMPK activator metformin could affect the P23H rhodopsin synthesis and folding. In cell models, metformin treatment improved P23H rhodopsin folding and traffic. In animal models of P23H RP, metformin treatment successfully enhanced P23H traffic to the rod outer segment, but this led to reduced photoreceptor function and increased photoreceptor cell death. The metformin-rescued P23H rhodopsin was still intrinsically unstable and led to increased structural instability of the rod outer segments. These data suggest that improving the traffic of misfolding rhodopsin mutants is unlikely to be a practical therapy, because of their intrinsic instability and long half-life in the outer segment, but also highlights the potential of altering translation through AMPK to improve protein function in other protein misfolding diseases.
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Affiliation(s)
| | - Monica Aguila
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Chikwado A. Opefi
- School of Biological Sciences, University of Essex, Wivenhoe Park, Essex, UK
| | - Kieron South
- School of Biological Sciences, University of Essex, Wivenhoe Park, Essex, UK
| | | | | | - Peter M. Munro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Naheed Kanuga
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | | | - Adam M. Dubis
- Moorfields Eye Hospital NHS Trust, 162 City Road, London, UK
| | | | - Anna B. Graca
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | | | - Robin R. Ali
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Sanae Sakami
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, USA
| | - Michael Y. Sherman
- Department of Biochemistry, Boston University Medical School, Boston, Massachusetts, MA, USA
| | - Philip J. Reeves
- School of Biological Sciences, University of Essex, Wivenhoe Park, Essex, UK
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15
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Chen Y, Brooks MJ, Gieser L, Swaroop A, Palczewski K. Transcriptome profiling of NIH3T3 cell lines expressing opsin and the P23H opsin mutant identifies candidate drugs for the treatment of retinitis pigmentosa. Pharmacol Res 2016; 115:1-13. [PMID: 27838510 DOI: 10.1016/j.phrs.2016.10.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/18/2016] [Accepted: 10/26/2016] [Indexed: 01/01/2023]
Abstract
Mammalian cells are commonly employed in screening assays to identify active compounds that could potentially affect the progression of different human diseases including retinitis pigmentosa (RP), a class of inherited diseases causing retinal degeneration with compromised vision. Using transcriptome analysis, we compared NIH3T3 cells expressing wildtype (WT) rod opsin with a retinal disease-causing single P23H mutation. Surprisingly, heterologous expression of WT opsin in NIH3T3 cells caused more than a 2-fold change in 783 out of 16,888 protein coding transcripts. The perturbed genes encoded extracellular matrix proteins, growth factors, cytoskeleton proteins, glycoproteins and metalloproteases involved in cell adhesion, morphology and migration. A different set of 347 transcripts was either up- or down-regulated when the P23H mutant opsin was expressed suggesting an altered molecular perturbation compared to WT opsin. Transcriptome perturbations elicited by drug candidates aimed at mitigating the effects of the mutant protein revealed that different drugs targeted distinct molecular pathways that resulted in a similar phenotype selected by a cell-based high-throughput screen. Thus, transcriptome profiling can provide essential information about the therapeutic potential of a candidate drug to restore normal gene expression in pathological conditions.
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Affiliation(s)
- Yuanyuan Chen
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Matthew J Brooks
- Neurobiology-Neurodegeneration & Repair Laboratory (N-NRL), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Linn Gieser
- Neurobiology-Neurodegeneration & Repair Laboratory (N-NRL), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair Laboratory (N-NRL), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States.
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16
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Chen Y, Tang H, Seibel W, Papoian R, Li X, Lambert NA, Palczewski K. A High-Throughput Drug Screening Strategy for Detecting Rhodopsin P23H Mutant Rescue and Degradation. Invest Ophthalmol Vis Sci 2015; 56:2553-67. [PMID: 25783607 DOI: 10.1167/iovs.14-16298] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Inherent instability of the P23H mutant opsin accounts for approximately 10% of autosomal dominant retinitis pigmentosa cases. Our purpose was to develop an overall set of reliable screening strategies to assess if either stabilization or enhanced degradation of mutant rhodopsin could rescue rod photoreceptors expressing this mutant protein. These strategies promise to reveal active compounds and clarify molecular mechanisms of biologically important processes, such as inhibition of target degradation or enhanced target folding. METHODS Cell-based bioluminescence reporter assays were developed and validated for high-throughput screening (HTS) of compounds that promote either stabilization or degradation of P23H mutant opsin. Such assays were further complemented by immunoblotting and image-based analyses. RESULTS Two stabilization assays of P23H mutant opsin were developed and validated, one based on β-galactosidase complementarity and a second assay involving bioluminescence resonance energy transfer (BRET) technology. Moreover, two additional assays evaluating mutant protein degradation also were employed, one based on the disappearance of luminescence and another employing the ALPHA immunoassay. Imaging of cells revealed the cellular localization of mutant rhodopsin, whereas immunoblots identified changes in the aggregation and glycosylation of P23H mutant opsin. CONCLUSIONS Our findings indicate that these initial HTS and following assays can identify active therapeutic compounds, even for difficult targets such as mutant rhodopsin. The assays are readily scalable and their function has been proven with model compounds. High-throughput screening, supported by automated imaging and classic immunoassays, can further characterize multiple steps and pathways in the biosynthesis and degradation of this essential visual system protein.
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Affiliation(s)
- Yuanyuan Chen
- Department of Pharmacology Case Western Reserve University, Cleveland, Ohio, United States
| | - Hong Tang
- Drug Discovery Center, College of Medicine, University of Cincinnati, Cincinnati, Ohio, United States
| | - William Seibel
- Drug Discovery Center, College of Medicine, University of Cincinnati, Cincinnati, Ohio, United States
| | - Ruben Papoian
- Drug Discovery Center, College of Medicine, University of Cincinnati, Cincinnati, Ohio, United States
| | - Xiaoyu Li
- Department of Pharmacology Case Western Reserve University, Cleveland, Ohio, United States
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia, United States
| | - Krzysztof Palczewski
- Department of Pharmacology Case Western Reserve University, Cleveland, Ohio, United States
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17
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D'Agostino M, Crespi A, Polishchuk E, Generoso S, Martire G, Colombo SF, Bonatti S. ER reorganization is remarkably induced in COS-7 cells accumulating transmembrane protein receptors not competent for export from the endoplasmic reticulum. J Membr Biol 2014; 247:1149-59. [PMID: 25086772 DOI: 10.1007/s00232-014-9710-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/15/2014] [Indexed: 10/24/2022]
Abstract
The newly synthesized mutant L501fsX533 Frizzled-4 form and the alpha3beta4 nicotinic acetylcholine receptor expressed in the absence of nicotine accumulate in the endoplasmic reticulum of COS-7 cells and induce the formation of large areas of smooth and highly convoluted cisternae. This results in a generalized block of the transport to the Golgi complex of newly synthesized proteins. Intriguingly, both effects happen peculiarly in COS-7 cells; HeLa, Huh-7, and HEK293 cells expressing the two receptors at similar level than COS-7 cells show normal ER and normal transport toward the plasma membrane. These results question the conclusion that a dominant-negative mechanism would explain the dominance of the mutant L501fsX533 Fz4 allele in the transmission of a form of Familial exudative vitreoretinopathy. Moreover, they indicate that the coordination of endoplasmic reticulum homeostasis in COS-7 cells is particularly error prone. This finding suggests that COS-7 cells may be extremely useful to study the molecular mechanisms regulating endoplasmic reticulum size and architecture.
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Affiliation(s)
- Massimo D'Agostino
- Department of Molecular medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
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18
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Zhang SX, Sanders E, Fliesler SJ, Wang JJ. Endoplasmic reticulum stress and the unfolded protein responses in retinal degeneration. Exp Eye Res 2014; 125:30-40. [PMID: 24792589 DOI: 10.1016/j.exer.2014.04.015] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 04/02/2014] [Accepted: 04/18/2014] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is the primary intracellular organelle responsible for protein and lipid biosynthesis, protein folding and trafficking, calcium homeostasis, and several other vital processes in cell physiology. Disturbance in ER function results in ER stress and subsequent activation of the unfolded protein response (UPR). The UPR up-regulates ER chaperones, reduces protein translation, and promotes clearance of cytotoxic misfolded proteins to restore ER homeostasis. If this vital process fails, the cell will be signaled to enter apoptosis, resulting in cell death. Sustained ER stress also can trigger an inflammatory response and exacerbate oxidative stress, both of which contribute synergistically to tissue damage. Studies performed over the past decade have implicated ER stress in a broad range of human diseases, including neurodegenerative diseases, cancer, diabetes, and vascular disorders. Several of these diseases also entail retinal dysfunction and degeneration caused by injury to retinal neurons and/or to the blood vessels that supply retinal cells with nutrients, trophic and homeostatic factors, oxygen, and other essential molecules, as well as serving as a conduit for removal of waste products and potentially toxic substances from the retina. Collectively, such injuries represent the leading cause of blindness world-wide in all age groups. Herein, we summarize recent progress on the study of ER stress and UPR signaling in retinal biology and discuss the molecular mechanisms and the potential clinical applications of targeting ER stress as a new therapeutic approach to prevent and treat neuronal degeneration in the retina.
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Affiliation(s)
- Sarah X Zhang
- Departments of Ophthalmology and Biochemistry, University at Buffalo, The State University of New York, Buffalo, NY, USA; SUNY Eye Institute, Buffalo, NY, USA.
| | - Emily Sanders
- Department of Medicine, Endocrinology and Diabetes, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Steven J Fliesler
- Departments of Ophthalmology and Biochemistry, University at Buffalo, The State University of New York, Buffalo, NY, USA; SUNY Eye Institute, Buffalo, NY, USA; Research Service, Veterans Administration Western New York Healthcare System, Buffalo, NY, USA
| | - Joshua J Wang
- Departments of Ophthalmology and Biochemistry, University at Buffalo, The State University of New York, Buffalo, NY, USA; SUNY Eye Institute, Buffalo, NY, USA
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19
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Nguyen ATH, Campbell M, Kiang AS, Humphries MM, Humphries P. Current therapeutic strategies for P23H RHO-linked RP. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:471-6. [PMID: 24664733 DOI: 10.1007/978-1-4614-3209-8_60] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The first autosomal dominant mutation identified to cause retinitis pigmentosa in the North American population was the substitution of proline to histidine at position 23 of the rhodopsin gene (P23H RHO). Many biochemical studies have demonstrated that P23H mutation induces rhodopsin (RHO) misfolding leading to endoplasmic reticulum stress. Herein, we review current thinking of this topic.
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Affiliation(s)
- Anh T H Nguyen
- The Ocular Genetics Unit, Smurfit Institute of Genetics, Trinity College Dublin, College Green, Dublin 2, Ireland,
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20
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Misawa T, Hayashi H, Sugiyama Y, Hashimoto Y. Discovery and structural development of small molecules that enhance transport activity of bile salt export pump mutant associated with progressive familial intrahepatic cholestasis type 2. Bioorg Med Chem 2012; 20:2940-9. [PMID: 22464344 DOI: 10.1016/j.bmc.2012.03.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 03/05/2012] [Accepted: 03/05/2012] [Indexed: 11/17/2022]
Abstract
Progressive familial intrahepatic cholestasis type 2 (PFIC2) is caused by hereditary mutations of bile salt export pump (BSEP), such as E297G BSEP, which is a folding-defective mutant that is unable to traffic beyond the endoplasmic reticulum (ER). 4-Phenylbutyric acid (4-PBA) enhances the cell surface expression and transport capacity of E297G BSEP, but has a relatively high dose (1mM or more) is required to show the effect. Here, we show that bile acids possibly act as pharmacological chaperones, promoting the proper folding and trafficking of E297G BSEP. We also describe the discovery and structural development of non-steroidal compounds with potent pharmacological chaperone activity for E297G BSEP.
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Affiliation(s)
- Takashi Misawa
- Institute of Molecular and Cellular Biosciencies, The University of Tokyo, 1-1-1 Bunkyo-ku, Tokyo 113-0032, Japan
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21
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Abstract
The eukaryotic cell is organized into membrane-covered compartments that are characterized by specific sets of proteins and biochemically distinct cellular processes. The appropriate subcellular localization of proteins is crucial because it provides the physiological context for their function. In this Commentary, we give a brief overview of the different mechanisms that are involved in protein trafficking and describe how aberrant localization of proteins contributes to the pathogenesis of many human diseases, such as metabolic, cardiovascular and neurodegenerative diseases, as well as cancer. Accordingly, modifying the disease-related subcellular mislocalization of proteins might be an attractive means of therapeutic intervention. In particular, cellular processes that link protein folding and cell signaling, as well as nuclear import and export, to the subcellular localization of proteins have been proposed as targets for therapeutic intervention. We discuss the concepts involved in the therapeutic restoration of disrupted physiological protein localization and therapeutic mislocalization as a strategy to inactivate disease-causing proteins.
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Affiliation(s)
- Mien-Chie Hung
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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22
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Griciuc A, Aron L, Ueffing M. ER stress in retinal degeneration: a target for rational therapy? Trends Mol Med 2011; 17:442-51. [PMID: 21620769 DOI: 10.1016/j.molmed.2011.04.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 04/07/2011] [Accepted: 04/13/2011] [Indexed: 10/18/2022]
Abstract
Mutations that cause rhodopsin misfolding and retention within the endoplasmic reticulum (ER) are a prominent cause of retinitis pigmentosa. Here, we discuss the hypothesis that the failure of photoreceptor neurons to adapt to the stress caused by rhodopsin accumulation in the ER leads to a global collapse of homeostasis and to retinal degeneration. We review the molecular mechanisms underlying the activity of local ER conformational sensors and stress-relaying modules and consider how ER-derived stress signals are amplified and implemented to impact on downstream processes, including rhodopsin clearance and cell fate control. The emerging view is that alterations to the systems responsible for the detection, transduction and implementation of ER stress might be used therapeutically to treat retinitis pigmentosa.
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Affiliation(s)
- Ana Griciuc
- Department of Protein Science, Helmholtz Zentrum Munich-German Research Center for Environmental Health, Neuherberg, Germany
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23
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OHGANE K, DODO K, HASHIMOTO Y. Structural Development Study of a Novel Pharmacological Chaperone for Folding-defective Rhodopsin Mutants Responsible for Retinitis Pigmentosa. YAKUGAKU ZASSHI 2011; 131:325-34. [DOI: 10.1248/yakushi.131.325] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kenji OHGANE
- Institute of Molecular and Cellular Biosciences, The University of Tokyo
| | | | - Yuichi HASHIMOTO
- Institute of Molecular and Cellular Biosciences, The University of Tokyo
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