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Ramkumar S, Jastrzebska B, Montenegro D, Sparrow JR, von Lintig J. Unraveling the mystery of ocular retinoid turnover: Insights from albino mice and the role of STRA6. J Biol Chem 2024; 300:105781. [PMID: 38395306 PMCID: PMC10950888 DOI: 10.1016/j.jbc.2024.105781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/02/2024] [Accepted: 02/17/2024] [Indexed: 02/25/2024] Open
Abstract
A delicate balance between photon absorption for vision and the protection of photoreceptors from light damage is pivotal for ocular health. This equilibrium is governed by the light-absorbing 11-cis-retinylidene chromophore of visual pigments, which, upon bleaching, transforms into all-trans-retinal and undergoes regeneration through an enzymatic pathway, named the visual cycle. Chemical side reactions of retinaldehyde during the recycling process can generate by-products that may result in a depletion of retinoids. In our study, we have clarified the crucial roles played by melanin pigmentation and the retinoid transporter STRA6 in preventing this loss and preserving the integrity of the visual cycle. Our experiments initially confirmed that consecutive green and blue light bleaching of isolated bovine rhodopsin produced 9-cis and 13-cis retinal. The same unusual retinoids were found in the retinas of mice exposed to intense light, with elevated concentrations observed in albino mice. Examining the metabolic fate of these visual cycle byproducts revealed that 9-cis-retinal, but not 13-cis-retinal, was recycled back to all-trans-retinal through an intermediate called isorhodopsin. However, investigations in Stra6 knockout mice unveiled that the generation of these visual cycle byproducts correlated with a light-induced loss of ocular retinoids and visual impairment. Collectively, our findings uncover important novel aspects of visual cycle dynamics, with implications for ocular health and photoreceptor integrity.
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Affiliation(s)
- Srinivasagan Ramkumar
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Beata Jastrzebska
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Diego Montenegro
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, USA; Departments of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, USA
| | - Janet R Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, New York, USA; Departments of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, USA
| | - Johannes von Lintig
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
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Engfer ZJ, Lewandowski D, Dong Z, Palczewska G, Zhang J, Kordecka K, Płaczkiewicz J, Panas D, Foik AT, Tabaka M, Palczewski K. Distinct mouse models of Stargardt disease display differences in pharmacological targeting of ceramides and inflammatory responses. Proc Natl Acad Sci U S A 2023; 120:e2314698120. [PMID: 38064509 PMCID: PMC10723050 DOI: 10.1073/pnas.2314698120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/25/2023] [Indexed: 12/17/2023] Open
Abstract
Mutations in many visual cycle enzymes in photoreceptors and retinal pigment epithelium (RPE) cells can lead to the chronic accumulation of toxic retinoid byproducts, which poison photoreceptors and the underlying RPE if left unchecked. Without a functional ATP-binding cassette, sub-family A, member 4 (ABCA4), there is an elevation of all-trans-retinal and prolonged buildup of all-trans-retinal adducts, resulting in a retinal degenerative disease known as Stargardt-1 disease. Even in this monogenic disorder, there is significant heterogeneity in the time to onset of symptoms among patients. Using a combination of molecular techniques, we studied Abca4 knockout (simulating human noncoding disease variants) and Abca4 knock-in mice (simulating human misfolded, catalytically inactive protein variants), which serve as models for Stargardt-1 disease. We compared the two strains to ascertain whether they exhibit differential responses to agents that affect cytokine signaling and/or ceramide metabolism, as alterations in either of these pathways can exacerbate retinal degenerative phenotypes. We found different degrees of responsiveness to maraviroc, a known immunomodulatory CCR5 antagonist, and to the ceramide-lowering agent AdipoRon, an agonist of the ADIPOR1 and ADIPOR2 receptors. The two strains also display different degrees of transcriptional deviation from matched WT controls. Our phenotypic comparison of the two distinct Abca4 mutant-mouse models sheds light on potential therapeutic avenues previously unexplored in the treatment of Stargardt disease and provides a surrogate assay for assessing the effectiveness for genome editing.
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Affiliation(s)
- Zachary J. Engfer
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
- Department of Physiology and Biophysics, University of California, Irvine, CA92697
| | - Dominik Lewandowski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
| | - Zhiqian Dong
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
| | - Grazyna Palczewska
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
| | - Jianye Zhang
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
| | - Katarzyna Kordecka
- Ophthalmic Biology Group, International Centre for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Jagoda Płaczkiewicz
- Ophthalmic Biology Group, International Centre for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Damian Panas
- International Centre for Translational Eye Research, Warsaw01-224, Poland
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Andrzej T. Foik
- Ophthalmic Biology Group, International Centre for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Marcin Tabaka
- International Centre for Translational Eye Research, Warsaw01-224, Poland
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw01-224, Poland
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA92697
- Department of Physiology and Biophysics, University of California, Irvine, CA92697
- Department of Chemistry, University of California, Irvine, CA92697
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA92697
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Castiglione GM, Chiu YLI, Gutierrez EDA, Van Nynatten A, Hauser FE, Preston M, Bhattacharyya N, Schott RK, Chang BSW. Convergent evolution of dim light vision in owls and deep-diving whales. Curr Biol 2023; 33:4733-4740.e4. [PMID: 37776863 DOI: 10.1016/j.cub.2023.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 08/21/2023] [Accepted: 09/05/2023] [Indexed: 10/02/2023]
Abstract
Animals with enhanced dim-light sensitivity are at higher risk of light-induced retinal degeneration when exposed to bright light conditions.1,2,3,4 This trade-off is mediated by the rod photoreceptor sensory protein, rhodopsin (RHO), and its toxic vitamin A chromophore by-product, all-trans retinal.5,6,7,8 Rod arrestin (Arr-1) binds to RHO and promotes sequestration of excess all-trans retinal,9,10 which has recently been suggested as a protective mechanism against photoreceptor cell death.2,11 We investigated Arr-1 evolution in animals at high risk of retinal damage due to periodic bright-light exposure of rod-dominated retinas. Here, we find the convergent evolution of enhanced Arr-1/RHO all-trans-retinal sequestration in owls and deep-diving whales. Statistical analyses reveal a parallel acceleration of Arr-1 evolutionary rates in these lineages, which is associated with the introduction of a rare Arr-1 mutation (Q69R) into the RHO-Arr-1 binding interface. Using in vitro assays, we find that this single mutation significantly enhances RHO-all-trans-retinal sequestration by ∼30%. This functional convergence across 300 million years of evolutionary divergence suggests that Arr-1 and RHO may play an underappreciated role in the photoprotection of the eye, with potentially vast clinical significance.
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Affiliation(s)
- Gianni M Castiglione
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Department of Ophthalmology & Visual Sciences, Vanderbilt University, Nashville, TN 37232, USA; Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada; Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; Evolutionary Studies, Vanderbilt University, Nashville, TN 37235, USA.
| | - Yan L I Chiu
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Eduardo de A Gutierrez
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Alexander Van Nynatten
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada; Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada
| | - Frances E Hauser
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada
| | - Matthew Preston
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Nihar Bhattacharyya
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada; Institute of Ophthalmology, University College London, London EC1V 2PD, UK
| | - Ryan K Schott
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; Department of Biology and Centre for Vision Research, York University, Toronto, ON M3J 1P3, Canada; Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
| | - Belinda S W Chang
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada; Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada.
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Choi SW, Seo S, Hong HK, Yoon SJ, Kim M, Moon S, Lee JY, Lim J, Lee JB, Woo SJ. Therapeutic Extracellular Vesicles from Tonsil-Derived Mesenchymal Stem Cells for the Treatment of Retinal Degenerative Disease. Tissue Eng Regen Med 2023; 20:951-964. [PMID: 37440108 PMCID: PMC10519919 DOI: 10.1007/s13770-023-00555-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 07/14/2023] Open
Abstract
BACKGROUND Retinal degenerative disease (RDD), one of the most common causes of blindness, is predominantly caused by the gradual death of retinal pigment epithelial cells (RPEs) and photoreceptors due to various causes. Cell-based therapies, such as stem cell implantation, have been developed for the treatment of RDD, but potential risks, including teratogenicity and immune reactions, have hampered their clinical application. Stem cell-derived extracellular vesicles (EVs) have recently emerged as a cell-free alternative therapeutic strategy; however, additional invasiveness and low yield of the stem cell extraction process is problematic. METHODS To overcome these limitations, we developed therapeutic EVs for the treatment of RDD which were extracted from tonsil-derived mesenchymal stem cells obtained from human tonsil tissue discarded as medical waste following tonsillectomy (T-MSC EVs). To verify the biocompatibility and cytoprotective effect of T-MSC EVs, we measured cell viability by co-culture with human RPE without or with toxic all-trans-retinal. To elucidate the cytoprotective mechanism of T-MSC EVs, we performed transcriptome sequencing using RNA extracted from RPEs. The in vivo protective effect of T-MSC EVs was evaluated using Pde6b gene knockout rats as an animal model of retinitis pigmentosa. RESULTS T-MSC EVs showed high biocompatibility and the human pigment epithelial cells were significantly protected in the presence of T-MSC EVs from the toxic effect of all-trans-retinal. In addition, T-MSC EVs showed a dose-dependent cell death-delaying effect in real-time quantification of cell death. Transcriptome sequencing analysis revealed that the efficient ability of T-MSC EVs to regulate intracellular oxidative stress may be one of the reasons explaining their excellent cytoprotective effect. Additionally, intravitreally injected T-MSC EVs had an inhibitory effect on the destruction of the outer nuclear layer in the Pde6b gene knockout rat. CONCLUSIONS Together, the results of this study indicate the preventive and therapeutic effects of T-MSC EVs during the initiation and development of retinal degeneration, which may be a beneficial alternative for the treatment of RDD.
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Affiliation(s)
- Seung Woo Choi
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Korea
| | - Sooin Seo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Korea
| | - Hye Kyoung Hong
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Korea
| | - So Jung Yoon
- Bundang CHA Biobank, CHA University College of Medicine, CHA University Bundang Medical Center, Seongnam, 13496, Korea
| | - Minah Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Korea
| | - Sunghyun Moon
- Department of Chemical Engineering, University of Seoul, 163 Seoul Siripdaero, Dongdaemun-Gu, Seoul, 02504, Korea
| | - Joo Yong Lee
- Department of Ophthalmology, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea
| | - Jaeseung Lim
- Cellatoz Therapeutics Lnc, Seongnam, 13487, Korea
| | - Jong Bum Lee
- Department of Chemical Engineering, University of Seoul, 163 Seoul Siripdaero, Dongdaemun-Gu, Seoul, 02504, Korea
| | - Se Joon Woo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Korea.
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Hong JD, Palczewski K. A short story on how chromophore is hydrolyzed from rhodopsin for recycling. Bioessays 2023; 45:e2300068. [PMID: 37454357 PMCID: PMC10614701 DOI: 10.1002/bies.202300068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/24/2023] [Accepted: 05/30/2023] [Indexed: 07/18/2023]
Abstract
The photocycle of visual opsins is essential to maintain the light sensitivity of the retina. The early physical observations of the rhodopsin photocycle by Böll and Kühne in the 1870s inspired over a century's worth of investigations on rhodopsin biochemistry. A single photon isomerizes the Schiff-base linked 11-cis-retinylidene chromophore of rhodopsin, converting it to the all-trans agonist to elicit phototransduction through photoactivated rhodopsin (Rho*). Schiff base hydrolysis of the agonist is a key step in the photocycle, not only diminishing ongoing phototransduction but also allowing for entry and binding of fresh 11-cis chromophore to regenerate the rhodopsin pigment and maintain light sensitivity. Many challenges have been encountered in measuring the rate of this hydrolysis, but recent advancements have facilitated studies of the hydrolysis within the native membrane environment of rhodopsin. These techniques can now be applied to study hydrolysis of agonist in other opsin proteins that mediate phototransduction or chromophore turnover. In this review, we discuss the progress that has been made in characterizing the rhodopsin photocycle and the journey to characterize the hydrolysis of its all-trans-retinylidene agonist.
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Affiliation(s)
- John D. Hong
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California Irvine, Irvine, CA 92697, USA
- Department of Chemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California Irvine, Irvine, CA 92697, USA
- Department of Chemistry, University of California Irvine, Irvine, CA 92697, USA
- Department of Physiology and Biophysics, University of California Irvine, Irvine, CA 92697, USA
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA 92697, USA
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6
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Tworak A, Kolesnikov AV, Hong JD, Choi EH, Luu JC, Palczewska G, Dong Z, Lewandowski D, Brooks MJ, Campello L, Swaroop A, Kiser PD, Kefalov VJ, Palczewski K. Rapid RGR-dependent visual pigment recycling is mediated by the RPE and specialized Müller glia. Cell Rep 2023; 42:112982. [PMID: 37585292 PMCID: PMC10530494 DOI: 10.1016/j.celrep.2023.112982] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/14/2023] [Accepted: 07/29/2023] [Indexed: 08/18/2023] Open
Abstract
In daylight, demand for visual chromophore (11-cis-retinal) exceeds supply by the classical visual cycle. This shortfall is compensated, in part, by the retinal G-protein-coupled receptor (RGR) photoisomerase, which is expressed in both the retinal pigment epithelium (RPE) and in Müller cells. The relative contributions of these two cellular pools of RGR to the maintenance of photoreceptor light responses are not known. Here, we use a cell-specific gene reactivation approach to elucidate the kinetics of RGR-mediated recovery of photoreceptor responses following light exposure. Electroretinographic measurements in mice with RGR expression limited to either cell type reveal that the RPE and a specialized subset of Müller glia contribute both to scotopic and photopic function. We demonstrate that 11-cis-retinal formed through photoisomerization is rapidly hydrolyzed, consistent with its role in a rapid visual pigment regeneration process. Our study shows that RGR provides a pan-retinal sink for all-trans-retinal released under sustained light conditions and supports rapid chromophore regeneration through the photic visual cycle.
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Affiliation(s)
- Aleksander Tworak
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA.
| | - Alexander V Kolesnikov
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA
| | - John D Hong
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA
| | - Elliot H Choi
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA
| | - Jennings C Luu
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA; Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Grazyna Palczewska
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA; Polgenix, Inc., Department of Medical Devices, Cleveland, OH 44106, USA
| | - Zhiqian Dong
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA
| | - Dominik Lewandowski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA
| | - Matthew J Brooks
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Laura Campello
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Philip D Kiser
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA; Department of Physiology & Biophysics, University of California, Irvine, Irvine, CA 92697, USA; Department of Clinical Pharmacy Practice, University of California, Irvine, Irvine, CA 92697, USA; Research Service, VA Long Beach Healthcare System, Long Beach, CA 90822, USA
| | - Vladimir J Kefalov
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA; Department of Physiology & Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA 92697, USA; Department of Physiology & Biophysics, University of California, Irvine, Irvine, CA 92697, USA; Department of Chemistry, University of California, Irvine, Irvine, CA 92697, USA; Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA.
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7
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Bassetto M, Zaluski J, Li B, Zhang J, Badiee M, Kiser PD, Tochtrop GP. Tuning the Metabolic Stability of Visual Cycle Modulators through Modification of an RPE65 Recognition Motif. J Med Chem 2023; 66:8140-8158. [PMID: 37279401 PMCID: PMC10824489 DOI: 10.1021/acs.jmedchem.3c00461] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In the eye, the isomerization of all-trans-retinal to 11-cis-retinal is accomplished by a metabolic pathway termed the visual cycle that is critical for vision. RPE65 is the essential trans-cis isomerase of this pathway. Emixustat, a retinoid-mimetic RPE65 inhibitor, was developed as a therapeutic visual cycle modulator and used for the treatment of retinopathies. However, pharmacokinetic liabilities limit its further development including: (1) metabolic deamination of the γ-amino-α-aryl alcohol, which mediates targeted RPE65 inhibition, and (2) unwanted long-lasting RPE65 inhibition. We sought to address these issues by more broadly defining the structure-activity relationships of the RPE65 recognition motif via the synthesis of a family of novel derivatives, which were tested in vitro and in vivo for RPE65 inhibition. We identified a potent secondary amine derivative with resistance to deamination and preserved RPE65 inhibitory activity. Our data provide insights into activity-preserving modifications of the emixustat molecule that can be employed to tune its pharmacological properties.
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Affiliation(s)
- Marco Bassetto
- Department of Physiology and Biophysics, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
- Research Service, VA Long Beach Healthcare System, Long Beach, California 90822, United States
| | - Jordan Zaluski
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Bowen Li
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Jianye Zhang
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
| | - Mohsen Badiee
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Philip D Kiser
- Department of Physiology and Biophysics, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
- Department of Clinical Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, University of California - Irvine, Irvine, California 92697, United States
- Research Service, VA Long Beach Healthcare System, Long Beach, California 90822, United States
| | - Gregory P Tochtrop
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
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8
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Gauthier M, Daniele G, Giroud B, Lafay F, Vulliet E, Jumarie C, Garric J, Boily M, Geffard O. The retinoid metabolism of Gammarus fossarum is disrupted by exogenous all-trans retinoic acid, citral, and methoprene but not by the technical formulation of glyphosate. Ecotoxicol Environ Saf 2023; 252:114602. [PMID: 36773439 DOI: 10.1016/j.ecoenv.2023.114602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/29/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Over the last decade, fluctuations of retinoids (RETs), also known as vitamin A and derivatives, have proved to be useful biomarkers to assess the environmental chemical pressure on a wide variety of non-target vertebrates. This use of RET-based biomarkers is of particular interest in the non-target sentinel species Gammarus fossarum in which RETs were shown to influence crucial physiological functions. To study and probe this metabolism in this crustacean model, a UHPLC-MS/MS method was developed to 1) identify and 2) monitor several endogenous RETs in unexposed females throughout their reproductive cycle. Then, females were exposed in controlled conditions to exogenous all-trans retinoic acid (atRA) and citral (CIT), a RA synthesis inhibitor, to simulate an excess or deficiency in RA. Perturbation of vitamin A metabolism by pesticides was further studied in response to methoprene (MET), a juvenile hormone analog as well as glyphosate (GLY). The developed method allowed, for the first time in this model, the identification of RA metabolites (all-trans 4-oxo and 13-cis 4-oxo RA), RA isomers (all-trans and 13-cis RA) as well as retinaldehyde (RALD) isomers (all-trans, 11-cis, and 13-cis RALD) and showed two distinct phases in the reproductive cycle. Retinoic acid successfully increased the tissular concentration of both RA isomers and CIT proved to be efficient at perturbating the conversion from RALD to RA. Methoprene perturbed the ratios between RA isomers whereas GLY had no observed effects on the RET system of G. fossarum females. We were able to discriminate different dynamics of RET perturbations by morphogens (atRA or CIT) or MET which highlights the plausible mediation of RETs in MET-induced disorders. Ultimately, our study shows that RETs are influenced by exposure to MET and strengthen their potential to assess aquatic ecosystem chemical status.
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Affiliation(s)
- Maxime Gauthier
- Unité de recherche RiverLy, INRAE, 5, Rue de la Doua C.S. 20244, Villeurbanne Cedex, France; Université du Québec à Montréal (UQAM), Département des sciences biologiques, 141, Avenue du Président-Kennedy, C.P. 8888, Succursale Centre-Ville, H3C 3P8 Montréal, Québec, Canada
| | - Gaëlle Daniele
- Univ. Lyon, CNRS, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, UMR 5280, 5, Rue de la Doua, F-69100 Villeurbanne, France
| | - Barbara Giroud
- Univ. Lyon, CNRS, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, UMR 5280, 5, Rue de la Doua, F-69100 Villeurbanne, France
| | - Florent Lafay
- Univ. Lyon, CNRS, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, UMR 5280, 5, Rue de la Doua, F-69100 Villeurbanne, France
| | - Emmanuelle Vulliet
- Univ. Lyon, CNRS, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, UMR 5280, 5, Rue de la Doua, F-69100 Villeurbanne, France
| | - Catherine Jumarie
- Université du Québec à Montréal (UQAM), Département des sciences biologiques, 141, Avenue du Président-Kennedy, C.P. 8888, Succursale Centre-Ville, H3C 3P8 Montréal, Québec, Canada
| | - Jeanne Garric
- Unité de recherche RiverLy, INRAE, 5, Rue de la Doua C.S. 20244, Villeurbanne Cedex, France
| | - Monique Boily
- Université du Québec à Montréal (UQAM), Département des sciences biologiques, 141, Avenue du Président-Kennedy, C.P. 8888, Succursale Centre-Ville, H3C 3P8 Montréal, Québec, Canada
| | - Olivier Geffard
- Unité de recherche RiverLy, INRAE, 5, Rue de la Doua C.S. 20244, Villeurbanne Cedex, France.
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9
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Gruhl T, Weinert T, Rodrigues MJ, Milne CJ, Ortolani G, Nass K, Nango E, Sen S, Johnson PJM, Cirelli C, Furrer A, Mous S, Skopintsev P, James D, Dworkowski F, Båth P, Kekilli D, Ozerov D, Tanaka R, Glover H, Bacellar C, Brünle S, Casadei CM, Diethelm AD, Gashi D, Gotthard G, Guixà-González R, Joti Y, Kabanova V, Knopp G, Lesca E, Ma P, Martiel I, Mühle J, Owada S, Pamula F, Sarabi D, Tejero O, Tsai CJ, Varma N, Wach A, Boutet S, Tono K, Nogly P, Deupi X, Iwata S, Neutze R, Standfuss J, Schertler G, Panneels V. Ultrafast structural changes direct the first molecular events of vision. Nature 2023; 615:939-944. [PMID: 36949205 PMCID: PMC10060157 DOI: 10.1038/s41586-023-05863-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 02/17/2023] [Indexed: 03/24/2023]
Abstract
Vision is initiated by the rhodopsin family of light-sensitive G protein-coupled receptors (GPCRs)1. A photon is absorbed by the 11-cis retinal chromophore of rhodopsin, which isomerizes within 200 femtoseconds to the all-trans conformation2, thereby initiating the cellular signal transduction processes that ultimately lead to vision. However, the intramolecular mechanism by which the photoactivated retinal induces the activation events inside rhodopsin remains experimentally unclear. Here we use ultrafast time-resolved crystallography at room temperature3 to determine how an isomerized twisted all-trans retinal stores the photon energy that is required to initiate the protein conformational changes associated with the formation of the G protein-binding signalling state. The distorted retinal at a 1-ps time delay after photoactivation has pulled away from half of its numerous interactions with its binding pocket, and the excess of the photon energy is released through an anisotropic protein breathing motion in the direction of the extracellular space. Notably, the very early structural motions in the protein side chains of rhodopsin appear in regions that are involved in later stages of the conserved class A GPCR activation mechanism. Our study sheds light on the earliest stages of vision in vertebrates and points to fundamental aspects of the molecular mechanisms of agonist-mediated GPCR activation.
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Affiliation(s)
- Thomas Gruhl
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Tobias Weinert
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Matthew J Rodrigues
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Christopher J Milne
- Photon Science Division, Laboratory for Femtochemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
- European XFEL, Schenefeld, Germany
| | - Giorgia Ortolani
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Karol Nass
- Photon Science Division, Laboratory for Femtochemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Eriko Nango
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
- RIKEN SPring-8 Center, Hyogo, Japan
| | - Saumik Sen
- Condensed Matter Theory Group, Laboratory for Theoretical and Computational Physics, Division of Scientific Computing, Theory and Data, Paul Scherrer Institute, Villigen PSI, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Philip J M Johnson
- Photon Science Division, Laboratory for Nonlinear Optics, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Claudio Cirelli
- Photon Science Division, Laboratory for Femtochemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Antonia Furrer
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
- Biologics Center, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Sandra Mous
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Petr Skopintsev
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA
| | - Daniel James
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Physics, Utah Valley University, Orem, UT, USA
| | - Florian Dworkowski
- Photon Science Division, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Petra Båth
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Demet Kekilli
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Dmitry Ozerov
- Division Scientific Computing, Theory and Data, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Rie Tanaka
- RIKEN SPring-8 Center, Hyogo, Japan
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hannah Glover
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Camila Bacellar
- Photon Science Division, Laboratory for Femtochemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Steffen Brünle
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | | | - Azeglio D Diethelm
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Dardan Gashi
- Photon Science Division, Laboratory for Femtochemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Guillaume Gotthard
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Ramon Guixà-González
- Condensed Matter Theory Group, Laboratory for Theoretical and Computational Physics, Division of Scientific Computing, Theory and Data, Paul Scherrer Institute, Villigen PSI, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Yasumasa Joti
- Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Victoria Kabanova
- Photon Science Division, Laboratory for Femtochemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
- Laboratory for Ultrafast X-ray Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Gregor Knopp
- Photon Science Division, Laboratory for Femtochemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Elena Lesca
- Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Pikyee Ma
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Isabelle Martiel
- Photon Science Division, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Jonas Mühle
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Shigeki Owada
- RIKEN SPring-8 Center, Hyogo, Japan
- Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Filip Pamula
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Daniel Sarabi
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Oliver Tejero
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Ching-Ju Tsai
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Niranjan Varma
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Anna Wach
- Institute of Nuclear Physics Polish Academy of Sciences, Kraców, Poland
- Operando X-ray Spectroscopy, Energy and Environment Division, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Sébastien Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Kensuke Tono
- Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Przemyslaw Nogly
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
- Dioscuri Center For Structural Dynamics of Receptors, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Kraków, Kraków, Poland
| | - Xavier Deupi
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
- Condensed Matter Theory Group, Laboratory for Theoretical and Computational Physics, Division of Scientific Computing, Theory and Data, Paul Scherrer Institute, Villigen PSI, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - So Iwata
- RIKEN SPring-8 Center, Hyogo, Japan
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Richard Neutze
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Jörg Standfuss
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Gebhard Schertler
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland.
- Department of Biology, ETH Zurich, Zurich, Switzerland.
| | - Valerie Panneels
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland.
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10
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Chen C, Yang K, He D, Yang B, Tao L, Chen J, Wu Y. Induction of ferroptosis by HO-1 contributes to retinal degeneration in mice with defective clearance of all-trans-retinal. Free Radic Biol Med 2023; 194:245-254. [PMID: 36509314 DOI: 10.1016/j.freeradbiomed.2022.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
The accumulation of all-trans-retinal (atRAL) in photoreceptors and the retinal pigment epithelium (RPE), which is induced by chaos in visual (retinoid) cycle, is closely associated with the pathogenesis of dry age-related macular degeneration (AMD) and autosomal recessive Stargardt's disease (STGD1). Although we have reported that the induction of ferroptosis by atRAL is an important cause of photoreceptor loss, but its mechanisms still remain unclear. In this study, we identified heme oxygenase-1 (HO-1) as an inducer of photoreceptor ferroptosis elicited by atRAL. In atRAL-loaded photoreceptor cells, inhibition of Kelch-like ECH-associated protein 1 (KEAP1) at least in part by reactive oxygen species (ROS) production evoked the release of nuclear factor-erythroid 2-related factor-2 (NRF2) from KEAP1, followed by the translocation of active NRF2 into the nucleus where it promoted the transcription of the Ho-1 gene, thereby leading to HO-1 overexpression in the cytosol. A significant elevation of Fe2+ levels in photoreceptor cells resulted from activation of HO-1 by atRAL, and it facilitated ROS overproduction and then triggered ferroptotic cell death through ROS-mediated lipid peroxidation. Both treatment with HO-1 repressor Zinc protoporphyrin IX (ZnPP) and knockout of Ho-1 gene clearly rescued photoreceptor cells against ferroptosis arising from atRAL overload. Light-exposed Abca4-/-Rdh8-/- mice rapidly display severe defects in atRAL clearance, and serve as an acute model of dry AMD and STGD1. HO-1 activation was distinctly observed in neural retina of Abca4-/-Rdh8-/- mice after exposure to light, and it was visibly relieved by intraperitoneally injected ferroptosis inhibitor ferrostatin-1. More notably, intraperitoneal administration of ZnPP effectively alleviated both photoreceptor degeneration and RPE atrophy in Abca4-/-Rdh8-/- mice in response to light exposure by repressing HO-1-mediated ferroptosis. Our study suggests that HO-1 is a key factor that regulates atRAL-induced ferroptosis in photoreceptors and the RPE, and its inhibition may hold promises for the therapy of dry AMD and STGD1.
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Affiliation(s)
- Chao Chen
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Kunhuan Yang
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Danxue He
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Bo Yang
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Lei Tao
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Jingmeng Chen
- School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Yalin Wu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China; Shenzhen Research Institute of Xiamen University, Shenzhen, 518063, Guangdong, China; Xiamen Eye Center of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361001, Fujian, China.
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11
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Montenegro D, Zhao J, Kim HJ, Shmarakov IO, Blaner WS, Sparrow JR. Products of the visual cycle are detected in mice lacking retinol binding protein 4, the only known vitamin A carrier in plasma. J Biol Chem 2022; 298:102722. [PMID: 36410431 PMCID: PMC9768380 DOI: 10.1016/j.jbc.2022.102722] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/01/2022] [Accepted: 11/14/2022] [Indexed: 11/21/2022] Open
Abstract
Efficient delivery of vitamin A to the retinal pigment epithelium is vital to the production of the light-sensitive visual chromophore 11-cis-retinal. Nevertheless, retinol binding protein 4 (RBP4) is the only known carrier of vitamin A in plasma. Here, we present new findings that further characterize the visual cycle in the presence of Rbp4 deficiency. In the face of impaired delivery of retinol in Rbp4-/- mice, we determined that 11-cis-retinaldehyde reached levels that were ∼60% of WT at 4 months of age and all-trans-retinyl ester was 18% of normal yet photoreceptor cell loss was apparent by 8 months of age. The lack of Rbp4 appeared to have a greater impact on scotopic rod-mediated responses than on cone function at early ages. Also, despite severely impaired delivery of retinol, bisretinoid lipofuscin that forms as a byproduct of the visual cycle was measurable by HPLC and by quantitative fundus autofluorescence. In mice carrying an Rpe65 amino acid variant that slows visual cycle kinetics, Rbp4 deficiency had a less pronounced effect on 11-cis-retinal levels. Finally, we found that ocular retinoids were not altered in mice expressing elevated adipose-derived total Rbp4 protein (hRBP4+/+AdiCre+/-). In conclusion, our findings are consistent with a model in which vitamin A can be delivered to the retina by Rbp4-independent pathways.
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Affiliation(s)
- Diego Montenegro
- Departments of Ophthalmology, Columbia University Medical Center, New York, New York, USA
| | - Jin Zhao
- Departments of Ophthalmology, Columbia University Medical Center, New York, New York, USA
| | - Hye Jin Kim
- Departments of Ophthalmology, Columbia University Medical Center, New York, New York, USA
| | - Igor O Shmarakov
- Departments of Medicine, Columbia University Medical Center, New York, New York, USA
| | - William S Blaner
- Departments of Medicine, Columbia University Medical Center, New York, New York, USA
| | - Janet R Sparrow
- Departments of Ophthalmology, Columbia University Medical Center, New York, New York, USA; Departments of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, USA.
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12
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Zhuang X, Ma J, Xu G, Sun Z. SHP-1 knockdown suppresses mitochondrial biogenesis and aggravates mitochondria-dependent apoptosis induced by all trans retinal through the STING/AMPK pathways. Mol Med 2022; 28:125. [PMID: 36273174 PMCID: PMC9588232 DOI: 10.1186/s10020-022-00554-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 10/06/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Oxidative stress-caused damage to the retinal pigment epithelium (RPE) underlies the onset and progression of age-related macular degeneration (AMD). Impaired mitochondrial biogenesis sensitizes RPE cells to mitochondrial dysfunction, energy insufficiency and death. Src-homology 2 domain-containing phosphatase (SHP)-1 is important in regulating immune responses and cell survival. However, its roles in cell survival are not always consistent. Until now, the effects of SHP-1 on RPE dysfunction, especially mitochondrial homeostasis, remain to be elucidated. We sought to clarify the effects of SHP-1 in RPE cells in response to atRAL-induced oxidative stress and determine the regulatory mechanisms involved. METHODS In the all trans retinal (atRAL)-induced oxidative stress model, we used the vector of lentivirus to knockdown the expression of SHP-1 in ARPE-19 cells. CCK-8 assay, Annexin V/PI staining and JC-1 staining were utilized to determine the cell viability, cell apoptosis and mitochondrial membrane potential. We also used immunoprecipitation to examine the ubiquitination modification of stimulator of interferon genes (STING) and its interaction with SHP-1. The expression levels of mitochondrial marker, proteins related to mitochondrial biogenesis, and signaling molecules involved were examined by western blotting analysis. RESULTS We found that SHP-1 knockdown predisposed RPE cells to apoptosis, aggravated mitochondrial damage, and repressed mitochondrial biogenesis after treatment with atRAL. Immunofluoresent staining and immunoprecipitation analysis confirmed that SHP-1 interacted with the endoplasmic reticulum-resident STING and suppressed K63-linked ubiquitination and activation of STING. Inhibition of STING with the specific antagonist H151 attenuated the effects of SHP-1 knockdown on mitochondrial biogenesis and oxidative damage. The adenosine monophosphate-activated protein kinase (AMPK) pathway acted as the crucial downstream target of STING and was involved in the regulatory processes. CONCLUSIONS These findings suggest that SHP-1 knockdown potentiates STING overactivation and represses mitochondrial biogenesis and cell survival, at least in part by blocking the AMPK pathway in RPE cells. Therefore, restoring mitochondrial health by regulating SHP-1 in RPE cells may be a potential therapeutic strategy for degenerative retinal diseases including AMD.
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Affiliation(s)
- Xiaonan Zhuang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
| | - Jun Ma
- Eye Institute, Eye & ENT Hospital, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
| | - Gezhi Xu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
| | - Zhongcui Sun
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, 83 Fenyang Road, Shanghai, 200031, China.
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.
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13
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Abstract
Retinoic acid (RA) functions as an essential signal for development of the vertebrate eye by controlling the transcriptional regulatory activity of RA receptors (RARs). During eye development, the optic vesicles and later the retina generate RA as a metabolite of vitamin A (retinol). Retinol is first converted to retinaldehyde by retinol dehydrogenase 10 (RDH10) and then to RA by all three retinaldehyde dehydrogenases (ALDH1A1, ALDH1A2, and ALDH1A3). In early mouse embryos, RA diffuses to tissues throughout the optic placode, optic vesicle, and adjacent mesenchyme to stimulate folding of the optic vesicle to form the optic cup. RA later generated by the retina is needed for further morphogenesis of the optic cup and surrounding perioptic mesenchyme; loss of RA at this stage leads to microphthalmia and cornea plus eyelid defects. RA functions by binding to nuclear RARs at RA response elements (RAREs) that either activate or repress transcription of key genes. Binding of RA to RARs regulates recruitment of transcriptional coregulators such as nuclear receptor coactivator (NCOA) or nuclear receptor corepressor (NCOR), which in turn control binding of the generic coactivator p300 or the generic corepressor PRC2. No genes have been identified as direct targets of RA signaling during eye development, so future studies need to focus on identifying such genes and their RAREs. Studies designed to learn how RA normally controls eye development in vivo will provide basic knowledge valuable for determining how developmental eye defects occur and for improving strategies to treat eye defects.
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Affiliation(s)
- Gregg Duester
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037, USA
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14
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Abstract
Carotenoids constitute an essential dietary component of animals and other non-carotenogenic species which use these pigments in both their modified and unmodified forms. Animals utilize uncleaved carotenoids to mitigate light damage and oxidative stress and to signal fitness and health. Carotenoids also serve as precursors of apocarotenoids including retinol, and its retinoid metabolites, which carry out essential functions in animals by forming the visual chromophore 11-cis-retinaldehyde. Retinoids, such as all-trans-retinoic acid, can also act as ligands of nuclear hormone receptors. The fact that enzymes and biochemical pathways responsible for the metabolism of carotenoids in animals bear resemblance to the ones in plants and other carotenogenic species suggests an evolutionary relationship. We will explore some of the modes of transmission of carotenoid genes from carotenogenic species to metazoans. This apparent relationship has been successfully exploited in the past to identify and characterize new carotenoid and retinoid modifying enzymes. We will review approaches used to identify putative animal carotenoid enzymes, and we will describe methods used to functionally validate and analyze the biochemistry of carotenoid modifying enzymes encoded by animals.
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Affiliation(s)
- Alexander R Moise
- Northern Ontario School of Medicine, Sudbury, ON, Canada; Department of Chemistry and Biochemistry, Biology and Biomolecular Sciences Program, Laurentian University, Sudbury, ON, Canada.
| | - Sepalika Bandara
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Johannes von Lintig
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
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15
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McKee AG, Kuntz CP, Ortega JT, Woods H, Most V, Roushar FJ, Meiler J, Jastrzebska B, Schlebach JP. Systematic Profiling of Temperature- and Retinal-Sensitive Rhodopsin Variants by Deep Mutational Scanning. J Biol Chem 2021; 297:101359. [PMID: 34756884 PMCID: PMC8649220 DOI: 10.1016/j.jbc.2021.101359] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 10/20/2021] [Accepted: 10/26/2021] [Indexed: 01/29/2023] Open
Abstract
Membrane protein variants with diminished conformational stability often exhibit enhanced cellular expression at reduced growth temperatures. The expression of “temperature-sensitive” variants is also typically sensitive to corrector molecules that bind and stabilize the native conformation. There are many examples of temperature-sensitive rhodopsin variants, the misfolding of which is associated with the molecular basis of retinitis pigmentosa. In this work, we employ deep mutational scanning to compare the effects of reduced growth temperature and 9-cis-retinal, an investigational corrector, on the plasma membrane expression of 700 rhodopsin variants in HEK293T cells. We find that the change in expression at reduced growth temperatures correlates with the response to 9-cis-retinal among variants bearing mutations within a hydrophobic transmembrane domain (TM2). The most sensitive variants appear to disrupt a native helical kink within this transmembrane domain. By comparison, mutants that alter the structure of a polar transmembrane domain (TM7) exhibit weaker responses to temperature and retinal that are poorly correlated. Statistical analyses suggest that this observed insensitivity cannot be attributed to a single variable, but likely arises from the composite effects of mutations on the energetics of membrane integration, the stability of the native conformation, and the integrity of the retinal-binding pocket. Finally, we show that the characteristics of purified temperature- and retinal-sensitive variants suggest that the proteostatic effects of retinal may be manifested during translation and cotranslational folding. Together, our findings highlight several biophysical constraints that appear to influence the sensitivity of genetic variants to temperature and small-molecule correctors.
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Affiliation(s)
- Andrew G McKee
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Charles P Kuntz
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Joseph T Ortega
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Hope Woods
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA; Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, USA
| | - Victoria Most
- Institute for Drug Development, Leipzig University, Leipzig, SAC, Germany
| | - Francis J Roushar
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA; Institute for Drug Development, Leipzig University, Leipzig, SAC, Germany
| | - Beata Jastrzebska
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
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16
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Petrosino JM, Longenecker JZ, Ramkumar S, Xu X, Dorn LE, Bratasz A, Yu L, Maurya S, Tolstikov V, Bussberg V, Janssen PM, Periasamy M, Kiebish MA, Duester G, von Lintig J, Ziouzenkova O, Accornero F. Paracardial fat remodeling affects systemic metabolism through alcohol dehydrogenase 1. J Clin Invest 2021; 131:141799. [PMID: 33586683 PMCID: PMC7880313 DOI: 10.1172/jci141799] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 12/10/2020] [Indexed: 11/17/2022] Open
Abstract
The relationship between adiposity and metabolic health is well established. However, very little is known about the fat depot, known as paracardial fat (pCF), located superior to and surrounding the heart. Here, we show that pCF remodels with aging and a high-fat diet and that the size and function of this depot are controlled by alcohol dehydrogenase 1 (ADH1), an enzyme that oxidizes retinol into retinaldehyde. Elderly individuals and individuals with obesity have low ADH1 expression in pCF, and in mice, genetic ablation of Adh1 is sufficient to drive pCF accumulation, dysfunction, and global impairments in metabolic flexibility. Metabolomics analysis revealed that pCF controlled the levels of circulating metabolites affecting fatty acid biosynthesis. Also, surgical removal of the pCF depot was sufficient to rescue the impairments in cardiometabolic flexibility and fitness observed in Adh1-deficient mice. Furthermore, treatment with retinaldehyde prevented pCF remodeling in these animals. Mechanistically, we found that the ADH1/retinaldehyde pathway works by driving PGC-1α nuclear translocation and promoting mitochondrial fusion and biogenesis in the pCF depot. Together, these data demonstrate that pCF is a critical regulator of cardiometabolic fitness and that retinaldehyde and its generating enzyme ADH1 act as critical regulators of adipocyte remodeling in the pCF depot.
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Affiliation(s)
- Jennifer M. Petrosino
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Jacob Z. Longenecker
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | | | - Xianyao Xu
- Department of Biomedical Engineering, Dorothy M. Davis Heart and Lung Research Institute
| | - Lisa E. Dorn
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | | | - Lianbo Yu
- Center for Biostatistics, Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio, USA
| | - Santosh Maurya
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | | | - Valerie Bussberg
- BERG, Precision Medicine Department, Framingham, Massachusetts, USA
| | - Paul M.L. Janssen
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Muthu Periasamy
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
- Department of Internal Medicine, University of Central Florida, Orlando, Florida, USA
| | | | - Gregg Duester
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Johannes von Lintig
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ouliana Ziouzenkova
- Department of Human Sciences, College of Education and Human Ecology, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Federica Accornero
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
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17
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Bada Juarez JF, Judge PJ, Adam S, Axford D, Vinals J, Birch J, Kwan TOC, Hoi KK, Yen HY, Vial A, Milhiet PE, Robinson CV, Schapiro I, Moraes I, Watts A. Structures of the archaerhodopsin-3 transporter reveal that disordering of internal water networks underpins receptor sensitization. Nat Commun 2021; 12:629. [PMID: 33504778 PMCID: PMC7840839 DOI: 10.1038/s41467-020-20596-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/10/2020] [Indexed: 12/11/2022] Open
Abstract
Many transmembrane receptors have a desensitized state, in which they are unable to respond to external stimuli. The family of microbial rhodopsin proteins includes one such group of receptors, whose inactive or dark-adapted (DA) state is established in the prolonged absence of light. Here, we present high-resolution crystal structures of the ground (light-adapted) and DA states of Archaerhodopsin-3 (AR3), solved to 1.1 Å and 1.3 Å resolution respectively. We observe significant differences between the two states in the dynamics of water molecules that are coupled via H-bonds to the retinal Schiff Base. Supporting QM/MM calculations reveal how the DA state permits a thermodynamic equilibrium between retinal isomers to be established, and how this same change is prevented in the ground state in the absence of light. We suggest that the different arrangement of internal water networks in AR3 is responsible for the faster photocycle kinetics compared to homologs.
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Affiliation(s)
- Juan F Bada Juarez
- Biochemistry Department, Oxford University, South Parks Road, Oxford, OX1 3QU, UK
| | - Peter J Judge
- Biochemistry Department, Oxford University, South Parks Road, Oxford, OX1 3QU, UK
| | - Suliman Adam
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Danny Axford
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Javier Vinals
- Biochemistry Department, Oxford University, South Parks Road, Oxford, OX1 3QU, UK
| | - James Birch
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX11 0FA, UK
| | - Tristan O C Kwan
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX11 0FA, UK
- National Physical Laboratory, Hampton Road, Teddington, London, TW11 0LW, UK
| | - Kin Kuan Hoi
- Chemistry Research Laboratory, Oxford University, Mansfield Road, Oxford, OX1 3TA, UK
| | - Hsin-Yung Yen
- OMass Therapeutics, The Schrodinger Building, Oxford Science Park, Oxford, OX4 4GE, UK
| | - Anthony Vial
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, University of Montpellier, Montpellier, France
| | - Pierre-Emmanuel Milhiet
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, University of Montpellier, Montpellier, France
| | - Carol V Robinson
- Chemistry Research Laboratory, Oxford University, Mansfield Road, Oxford, OX1 3TA, UK
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Isabel Moraes
- Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX11 0FA, UK.
- National Physical Laboratory, Hampton Road, Teddington, London, TW11 0LW, UK.
| | - Anthony Watts
- Biochemistry Department, Oxford University, South Parks Road, Oxford, OX1 3QU, UK.
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18
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Blum E, Zhang J, Korshin E, Palczewski K, Gruzman A. Development of chiral fluorinated alkyl derivatives of emixustat as drug candidates for the treatment of retinal degenerative diseases. Bioorg Med Chem Lett 2020; 30:127421. [PMID: 32717613 PMCID: PMC7494577 DOI: 10.1016/j.bmcl.2020.127421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 11/16/2022]
Abstract
The discovery of how a photon is converted into a chemical signal is one of the most important achievements in the field of vision. A key molecule in this process is the visual chromophore retinal. Several eye diseases are attributed to the abnormal metabolism of retinal in the retina and the retinal pigment epithelium. Also, the accumulation of two toxic retinal derivatives, N-retinylidene-N-retinylethanolamine and the retinal dimer, can damage the retina leading to blindness. RPE65 (Retinal pigment epithelium-specific 65 kDa protein) is one of the central enzymes that regulates the metabolism of retinal and the formation of its toxic metabolites. Its inhibition might decrease the rate of the retina's degeneration by limiting the amount of retinal and its toxic byproducts. Two RPE65 inhibitors, (R)-emixustat and (R)-MB001, were recently developed for this purpose.
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Affiliation(s)
- Eliav Blum
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Jianye Zhang
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA 92697, USA
| | - Edward Korshin
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA 92697, USA; Departments of Physiology and Biophysics, and Chemistry, University of California, Irvine, CA 92697, USA
| | - Arie Gruzman
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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19
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Cross SH, Mckie L, Hurd TW, Riley S, Wills J, Barnard AR, Young F, MacLaren RE, Jackson IJ. The nanophthalmos protein TMEM98 inhibits MYRF self-cleavage and is required for eye size specification. PLoS Genet 2020; 16:e1008583. [PMID: 32236127 PMCID: PMC7153906 DOI: 10.1371/journal.pgen.1008583] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/13/2020] [Accepted: 03/06/2020] [Indexed: 12/31/2022] Open
Abstract
The precise control of eye size is essential for normal vision. TMEM98 is a highly conserved and widely expressed gene which appears to be involved in eye size regulation. Mutations in human TMEM98 are found in patients with nanophthalmos (very small eyes) and variants near the gene are associated in population studies with myopia and increased eye size. As complete loss of function mutations in mouse Tmem98 result in perinatal lethality, we produced mice deficient for Tmem98 in the retinal pigment epithelium (RPE), where Tmem98 is highly expressed. These mice have greatly enlarged eyes that are very fragile with very thin retinas, compressed choroid and thin sclera. To gain insight into the mechanism of action we used a proximity labelling approach to discover interacting proteins and identified MYRF as an interacting partner. Mutations of MYRF are also associated with nanophthalmos. The protein is an endoplasmic reticulum-tethered transcription factor which undergoes autoproteolytic cleavage to liberate the N-terminal part which then translocates to the nucleus where it acts as a transcription factor. We find that TMEM98 inhibits the self-cleavage of MYRF, in a novel regulatory mechanism. In RPE lacking TMEM98, MYRF is ectopically activated and abnormally localised to the nuclei. Our findings highlight the importance of the interplay between TMEM98 and MYRF in determining the size of the eye.
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Affiliation(s)
- Sally H. Cross
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| | - Lisa Mckie
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Toby W. Hurd
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Sam Riley
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Jimi Wills
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Alun R. Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Fiona Young
- Electron Microscopy, Pathology, Western General Hospital, Edinburgh, United Kingdom
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Ian J. Jackson
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
- Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
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20
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Belyaeva OV, Adams MK, Popov KM, Kedishvili NY. Generation of Retinaldehyde for Retinoic Acid Biosynthesis. Biomolecules 2019; 10:biom10010005. [PMID: 31861321 PMCID: PMC7022914 DOI: 10.3390/biom10010005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 12/14/2019] [Accepted: 12/16/2019] [Indexed: 12/11/2022] Open
Abstract
The concentration of all-trans-retinoic acid, the bioactive derivative of vitamin A, is critically important for the optimal performance of numerous physiological processes. Either too little or too much of retinoic acid in developing or adult tissues is equally harmful. All-trans-retinoic acid is produced by the irreversible oxidation of all-trans-retinaldehyde. Thus, the concentration of retinaldehyde as the immediate precursor of retinoic acid has to be tightly controlled. However, the enzymes that produce all-trans-retinaldehyde for retinoic acid biosynthesis and the mechanisms responsible for the control of retinaldehyde levels have not yet been fully defined. The goal of this review is to summarize the current state of knowledge regarding the identities of physiologically relevant retinol dehydrogenases, their enzymatic properties, and tissue distribution, and to discuss potential mechanisms for the regulation of the flux from retinol to retinaldehyde.
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Affiliation(s)
- Olga V. Belyaeva
- Department of Biochemistry and Molecular Genetics, Schools of Medicine and Dentistry, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (K.M.P.); (N.Y.K.)
- Correspondence: ; Tel.: +1-205-996-4024
| | - Mark K. Adams
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA;
| | - Kirill M. Popov
- Department of Biochemistry and Molecular Genetics, Schools of Medicine and Dentistry, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (K.M.P.); (N.Y.K.)
| | - Natalia Y. Kedishvili
- Department of Biochemistry and Molecular Genetics, Schools of Medicine and Dentistry, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (K.M.P.); (N.Y.K.)
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21
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Giménez-Dejoz J, Weber S, Fernández-Pardo Á, Möller G, Adamski J, Porté S, Parés X, Farrés J. Engineering aldo-keto reductase 1B10 to mimic the distinct 1B15 topology and specificity towards inhibitors and substrates, including retinoids and steroids. Chem Biol Interact 2019; 307:186-194. [PMID: 31028727 DOI: 10.1016/j.cbi.2019.04.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 03/27/2019] [Accepted: 04/23/2019] [Indexed: 12/18/2022]
Abstract
The aldo-keto reductase (AKR) superfamily comprises NAD(P)H-dependent enzymes that catalyze the reduction of a variety of carbonyl compounds. AKRs are classified in families and subfamilies. Humans exhibit three members of the AKR1B subfamily: AKR1B1 (aldose reductase, participates in diabetes complications), AKR1B10 (overexpressed in several cancer types), and the recently described AKR1B15. AKR1B10 and AKR1B15 share 92% sequence identity, as well as the capability of being active towards retinaldehyde. However, AKR1B10 and AKR1B15 exhibit strong differences in substrate specificity and inhibitor selectivity. Remarkably, their substrate-binding sites are the most divergent parts between them. Out of 27 residue substitutions, six are changes to Phe residues in AKR1B15. To investigate the participation of these structural changes, especially the Phe substitutions, in the functional features of each enzyme, we prepared two AKR1B10 mutants. The AKR1B10 m mutant carries a segment of six AKR1B15 residues (299-304, including three Phe residues) in the respective AKR1B10 region. An additional substitution (Val48Phe) was incorporated in the second mutant, AKR1B10mF48. This resulted in structures with smaller and more hydrophobic binding pockets, more similar to that of AKR1B15. In general, the AKR1B10 mutants mirrored well the specific functional features of AKR1B15, i.e., the different preferences towards the retinaldehyde isomers, the much higher activity with steroids and ketones, and the unique behavior with inhibitors. It can be concluded that the Phe residues of loop C (299-304) contouring the substrate-binding site, in addition to Phe at position 48, strongly contribute to a narrower and more hydrophobic site in AKR1B15, which would account for its functional uniqueness. In addition, we have investigated the AKR1B10 and AKR1B15 activity toward steroids. While AKR1B10 only exhibits residual activity, AKR1B15 is an efficient 17-ketosteroid reductase. Finally, the functional role of AKR1B15 in steroid and retinaldehyde metabolism is discussed.
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Affiliation(s)
- Joan Giménez-Dejoz
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Barcelona, Spain
| | - Susanne Weber
- Research Unit Molecular Endocrinology and Metabolism, Helmholtz Zentrum München, 85764, Neuherberg, Germany
| | - Álvaro Fernández-Pardo
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Barcelona, Spain
| | - Gabriele Möller
- Research Unit Molecular Endocrinology and Metabolism, Helmholtz Zentrum München, 85764, Neuherberg, Germany
| | - Jerzy Adamski
- Research Unit Molecular Endocrinology and Metabolism, Helmholtz Zentrum München, 85764, Neuherberg, Germany; Lehrstuhl für Experimentelle Genetik, Technische Universität München, 85356, Freising-Weihenstephan, Germany; German Center for Diabetes Research, 85764, Neuherberg, Germany
| | - Sergio Porté
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Barcelona, Spain
| | - Xavier Parés
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Barcelona, Spain
| | - Jaume Farrés
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Barcelona, Spain.
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22
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Munro RA, de Vlugt J, Ward ME, Kim SY, Lee KA, Jung KH, Ladizhansky V, Brown LS. Biosynthetic production of fully carbon-13 labeled retinal in E. coli for structural and functional studies of rhodopsins. J Biomol NMR 2019; 73:49-58. [PMID: 30719609 DOI: 10.1007/s10858-019-00225-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 01/16/2019] [Indexed: 06/09/2023]
Abstract
The isomerization of a covalently bound retinal is an integral part of both microbial and animal rhodopsin function. As such, detailed structure and conformational changes in the retinal binding pocket are of significant interest and are studied in various NMR, FTIR, and Raman spectroscopy experiments, which commonly require isotopic labeling of retinal. Unfortunately, the de novo organic synthesis of an isotopically-labeled retinal is complex and often cost-prohibitive, especially for large scale expression required for solid-state NMR. We present the novel protocol for biosynthetic production of an isotopically labeled retinal ligand concurrently with an apoprotein in E. coli as a cost-effective alternative to the de novo organic synthesis. Previously, the biosynthesis of a retinal precursor, β-carotene, has been introduced into many different organisms. We extended this system to the prototrophic E. coli expression strain BL21 in conjunction with the inducible expression of a β-dioxygenase and proteo-opsin. To demonstrate the applicability of this system, we were able to assign several new carbon resonances for proteorhodopsin-bound retinal by using fully 13C-labeled glucose as the sole carbon source. Furthermore, we demonstrated that this biosynthetically produced retinal can be extracted from E. coli cells by applying a hydrophobic solvent layer to the growth medium and reconstituted into an externally produced opsin of any desired labeling pattern.
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Affiliation(s)
- Rachel A Munro
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Jeffrey de Vlugt
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Meaghan E Ward
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - So Young Kim
- Deptartment of Life Science, Institute of Biological Interfaces, Sogang University, Shinsu-Dong 1, Mapo-Gu, Seoul, 121-742, Republic of Korea
- Division of Biotechnology, College of Environmental & Bioresource Sciences, Chonbuk National University, Jeonju, Republic of Korea
| | - Keon Ah Lee
- Deptartment of Life Science, Institute of Biological Interfaces, Sogang University, Shinsu-Dong 1, Mapo-Gu, Seoul, 121-742, Republic of Korea
| | - Kwang-Hwan Jung
- Deptartment of Life Science, Institute of Biological Interfaces, Sogang University, Shinsu-Dong 1, Mapo-Gu, Seoul, 121-742, Republic of Korea
| | - Vladimir Ladizhansky
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Leonid S Brown
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada.
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23
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Jafri AJA, Agarwal R, Iezhitsa I, Agarwal P, Ismail NM. Taurine protects against NMDA-induced retinal damage by reducing retinal oxidative stress. Amino Acids 2019; 51:641-646. [PMID: 30656415 DOI: 10.1007/s00726-019-02696-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 01/04/2019] [Indexed: 12/29/2022]
Abstract
This study aimed to evaluate effect of TAU on NMDA-induced changes in retinal redox status, retinal cell apoptosis and retinal morphology in Sprague-Dawley rats. Taurine was injected intravitreally as pre-, co- or post-treatment with NMDA and 7 days post-treatment retinae were processed for estimation of oxidative stress, retinal morphology using H&E staining and retinal cell apoptosis using TUNEL staining. Treatment with TAU, particularly pre-treatment, significantly increased retinal glutathione, superoxide dismutase and catalase levels compared to NMDA-treated rats; whereas, the levels of malondialdehyde reduced significantly. Reduction in retinal oxidative stress in TAU pre-treated group was associated with significantly greater fractional thickness of ganglion cell layer within inner retina and retinal cell density in inner retina. TUNEL staining showed significantly reduced apoptotic cell count in TAU pre-treated group compared to NMDA group. It could be concluded that TAU protects against NMDA-induced retinal injury in rats by reducing retinal oxidative stress.
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Affiliation(s)
- Azliana Jusnida Ahmad Jafri
- Center for Neuroscience Research, Faculty of Medicine, Universiti Teknologi MARA Sungai Buloh Campus, Sungai Buloh, Selangor, Malaysia
| | - Renu Agarwal
- Center for Neuroscience Research, Faculty of Medicine, Universiti Teknologi MARA Sungai Buloh Campus, Sungai Buloh, Selangor, Malaysia.
- I-PPerForM, Faculty of Medicine, Universiti Teknologi MARA Sungai Buloh Campus, Sungai Buloh, Selangor, Malaysia.
| | - Igor Iezhitsa
- Center for Neuroscience Research, Faculty of Medicine, Universiti Teknologi MARA Sungai Buloh Campus, Sungai Buloh, Selangor, Malaysia
- Research Institute of Pharmacology, Volgograd State Medical University, Volgograd, Russia
| | - Puneet Agarwal
- Faculty of Medicine, International Medical University, IMU Clinical School, Seremban, Malaysia
| | - Nafeeza Mohd Ismail
- Faculty of Medicine, International Medical University, IMU Clinical School, Seremban, Malaysia
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24
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Lenis TL, Hu J, Ng SY, Jiang Z, Sarfare S, Lloyd MB, Esposito NJ, Samuel W, Jaworski C, Bok D, Finnemann SC, Radeke MJ, Redmond TM, Travis GH, Radu RA. Expression of ABCA4 in the retinal pigment epithelium and its implications for Stargardt macular degeneration. Proc Natl Acad Sci U S A 2018; 115:E11120-E11127. [PMID: 30397118 PMCID: PMC6255167 DOI: 10.1073/pnas.1802519115] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recessive Stargardt disease (STGD1) is an inherited blinding disorder caused by mutations in the Abca4 gene. ABCA4 is a flippase in photoreceptor outer segments (OS) that translocates retinaldehyde conjugated to phosphatidylethanolamine across OS disc membranes. Loss of ABCA4 in Abca4-/- mice and STGD1 patients causes buildup of lipofuscin in the retinal pigment epithelium (RPE) and degeneration of photoreceptors, leading to blindness. No effective treatment currently exists for STGD1. Here we show by several approaches that ABCA4 is additionally expressed in RPE cells. (i) By in situ hybridization analysis and by RNA-sequencing analysis, we show the Abca4 mRNA is expressed in human and mouse RPE cells. (ii) By quantitative immunoblotting, we show that the level of ABCA4 protein in homogenates of wild-type mouse RPE is about 1% of the level in neural retina homogenates. (iii) ABCA4 immunofluorescence is present in RPE cells of wild-type and Mertk-/- but not Abca4-/- mouse retina sections, where it colocalizes with endolysosomal proteins. To elucidate the role of ABCA4 in RPE cells, we generated a line of genetically modified mice that express ABCA4 in RPE cells but not in photoreceptors. Mice from this line on the Abca4-/- background showed partial rescue of photoreceptor degeneration and decreased lipofuscin accumulation compared with nontransgenic Abca4-/- mice. We propose that ABCA4 functions to recycle retinaldehyde released during proteolysis of rhodopsin in RPE endolysosomes following daily phagocytosis of distal photoreceptor OS. ABCA4 deficiency in the RPE may play a role in the pathogenesis of STGD1.
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Affiliation(s)
- Tamara L Lenis
- Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Jane Hu
- Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Sze Yin Ng
- Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Zhichun Jiang
- Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Shanta Sarfare
- Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Marcia B Lloyd
- Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | | | - William Samuel
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20814
| | - Cynthia Jaworski
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20814
| | - Dean Bok
- Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | | | - Monte J Radeke
- Neuroscience Research Institute, University of California, Santa Barbara, CA 93106
| | - T Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20814
| | - Gabriel H Travis
- Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Roxana A Radu
- Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095;
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25
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Kim YS, Kato HE, Yamashita K, Ito S, Inoue K, Ramakrishnan C, Fenno LE, Evans KE, Paggi JM, Dror RO, Kandori H, Kobilka BK, Deisseroth K. Crystal structure of the natural anion-conducting channelrhodopsin GtACR1. Nature 2018; 561:343-348. [PMID: 30158696 PMCID: PMC6340299 DOI: 10.1038/s41586-018-0511-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 08/13/2018] [Indexed: 01/08/2023]
Abstract
The naturally occurring channelrhodopsin variant anion channelrhodopsin-1 (ACR1), discovered in the cryptophyte algae Guillardia theta, exhibits large light-gated anion conductance and high anion selectivity when expressed in heterologous settings, properties that support its use as an optogenetic tool to inhibit neuronal firing with light. However, molecular insight into ACR1 is lacking owing to the absence of structural information underlying light-gated anion conductance. Here we present the crystal structure of G. theta ACR1 at 2.9 Å resolution. The structure reveals unusual architectural features that span the extracellular domain, retinal-binding pocket, Schiff-base region, and anion-conduction pathway. Together with electrophysiological and spectroscopic analyses, these findings reveal the fundamental molecular basis of naturally occurring light-gated anion conductance, and provide a framework for designing the next generation of optogenetic tools.
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Affiliation(s)
- Yoon Seok Kim
- Department of Bioengineering, Department of Psychiatry and Behavioral Sciences, and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Hideaki E Kato
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
- PRESTO, Japan Science and Technology Agency, Honcho, Kawaguchi, Japan.
| | | | - Shota Ito
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
| | - Keiichi Inoue
- PRESTO, Japan Science and Technology Agency, Honcho, Kawaguchi, Japan
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
| | - Charu Ramakrishnan
- Department of Bioengineering, Department of Psychiatry and Behavioral Sciences, and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Lief E Fenno
- Department of Bioengineering, Department of Psychiatry and Behavioral Sciences, and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Kathryn E Evans
- Department of Bioengineering, Department of Psychiatry and Behavioral Sciences, and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Joseph M Paggi
- Department of Computer Science, Stanford University, Stanford, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Ron O Dror
- Department of Computer Science, Stanford University, Stanford, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, Japan
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Karl Deisseroth
- Department of Bioengineering, Department of Psychiatry and Behavioral Sciences, and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
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26
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Faramarzi S, Feng J, Mertz B. Allosteric Effects of the Proton Donor on the Microbial Proton Pump Proteorhodopsin. Biophys J 2018; 115:1240-1250. [PMID: 30219284 DOI: 10.1016/j.bpj.2018.08.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/21/2018] [Accepted: 08/22/2018] [Indexed: 11/17/2022] Open
Abstract
Proteorhodopsin (PR) is a microbial proton pump that is ubiquitous in marine environments and may play an important role in the oceanic carbon cycle. Photoisomerization of the retinal chromophore in PR leads to a series of proton transfers between specific acidic amino acid residues and the Schiff base of retinal, culminating in a proton motive force to facilitate ATP synthesis. The proton donor in a similar retinal protein, bacteriorhodopsin, acts as a latch to allow the influx of bulk water. However, it is unclear if the proton donor in PR, E108, utilizes the same latch mechanism to become internally hydrated. Here, we used molecular dynamics simulations to model the changes in internal hydration of the blue variant of PR during photoactivation with the proton donor in protonated and deprotonated states. We find that there is a stark contrast in the levels of internal hydration of the cytoplasmic half of PR based on the protonation state of E108. Instead of a latch mechanism, deprotonation of E108 acts as a gate, taking advantage of a nearby polar residue (S61) to promote the formation of a stable water wire from bulk cytoplasm to the retinal-binding pocket over hundreds of nanoseconds. No large-scale conformational changes occur in PR over the microsecond timescale. This subtle yet clear difference in the effect of deprotonation of the proton donor in PR may help explain why the photointermediates that involve the proton donor (i.e., M and N states) have timescales that are orders of magnitude different from the archaeal proton pump, bacteriorhodopsin. In general, our study highlights the importance of understanding how structural fluctuations lead to differences in the way that retinal proteins accomplish the same task.
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Affiliation(s)
- Sadegh Faramarzi
- C. Eugene Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Jun Feng
- C. Eugene Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Blake Mertz
- C. Eugene Department of Chemistry, West Virginia University, Morgantown, West Virginia.
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27
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Abstract
Channelrhodopsin-2 (ChR2) is a light-sensitive ion channel widely used in optogenetics. Photoactivation triggers a trans-to-cis isomerization of a covalently bound retinal. Ensuing conformational changes open a cation-selective channel. We explore the structural dynamics in the early photocycle leading to channel opening by classical (MM) and quantum mechanical (QM) molecular simulations. With QM/MM simulations, we generated a protein-adapted force field for the retinal chromophore, which we validated against absorption spectra. In a 4-µs MM simulation of a dark-adapted ChR2 dimer, water entered the vestibules of the closed channel. Retinal all-trans to 13-cis isomerization, simulated with metadynamics, triggered a major restructuring of the charge cluster forming the channel gate. On a microsecond time scale, water penetrated the gate to form a membrane-spanning preopen pore between helices H1, H2, H3, and H7. This influx of water into an ion-impermeable preopen pore is consistent with time-resolved infrared spectroscopy and electrophysiology experiments. In the retinal 13-cis state, D253 emerged as the proton acceptor of the Schiff base. Upon proton transfer from the Schiff base to D253, modeled by QM/MM simulations, we obtained an early-M/P2390-like intermediate. Rapid rotation of the unprotonated Schiff base toward the cytosolic side effectively prevents its reprotonation from the extracellular side. From MM and QM simulations, we gained detailed insight into the mechanism of ChR2 photoactivation and early events in pore formation. By rearranging the network of charges and hydrogen bonds forming the gate, water emerges as a key player in light-driven ChR2 channel opening.
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Affiliation(s)
- Albert Ardevol
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany;
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany;
- Department of Physics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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28
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Srinivasan S, Fernández-Sampedro MA, Morillo M, Ramon E, Jiménez-Rosés M, Cordomí A, Garriga P. Human Blue Cone Opsin Regeneration Involves Secondary Retinal Binding with Analog Specificity. Biophys J 2018; 114:1285-1294. [PMID: 29590586 PMCID: PMC5883618 DOI: 10.1016/j.bpj.2018.01.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 01/22/2018] [Accepted: 01/29/2018] [Indexed: 12/16/2022] Open
Abstract
Human color vision is mediated by the red, green, and blue cone visual pigments. Cone opsins are G-protein-coupled receptors consisting of an opsin apoprotein covalently linked to the 11-cis-retinal chromophore. All visual pigments share a common evolutionary origin, and red and green cone opsins exhibit a higher homology, whereas blue cone opsin shows more resemblance to the dim light receptor rhodopsin. Here we show that chromophore regeneration in photoactivated blue cone opsin exhibits intermediate transient conformations and a secondary retinoid binding event with slower binding kinetics. We also detected a fine-tuning of the conformational change in the photoactivated blue cone opsin binding site that alters the retinal isomer binding specificity. Furthermore, the molecular models of active and inactive blue cone opsins show specific molecular interactions in the retinal binding site that are not present in other opsins. These findings highlight the differential conformational versatility of human cone opsin pigments in the chromophore regeneration process, particularly compared to rhodopsin, and point to relevant functional, unexpected roles other than spectral tuning for the cone visual pigments.
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Affiliation(s)
| | | | | | - Eva Ramon
- Universitat Politècnica de Catalunya, Terrassa, Spain
| | - Mireia Jiménez-Rosés
- Unitat de Bioestadística Bellaterra, Laboratori de Medicina Computacional, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Arnau Cordomí
- Unitat de Bioestadística Bellaterra, Laboratori de Medicina Computacional, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Pere Garriga
- Universitat Politècnica de Catalunya, Terrassa, Spain.
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29
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Abstract
Three types of cone cells exist in the human retina, each containing a different pigment responsible for the initial step of phototransduction. These pigments are distinguished by their specific absorbance maxima: 425 nm (blue), 530 nm (green), and 560 nm (red). Each pigment contains a common chromophore, 11-cis-retinal covalently bound to an opsin protein via a Schiff base. The 11-cis-retinal protonated Schiff base has an absorbance maxima at 440 nm in methanol. Unfortunately, the chemistry that allows the same chromophore to interact with different opsin proteins to tune the absorbance of the resulting pigments to distinct λmax values is poorly understood. Rhodopsin is the only pigment with a native structure determined at high resolution. Homology models for cone pigments have been generated, but experimentally determined structures are needed for a precise understanding of spectral tuning. The principal obstacle to solving the structures of cone pigments has been their innate instability in recombinant constructs. By inserting five different thermostabilizing proteins (BRIL, T4L, PGS, RUB, and FLAV) into the recombinant green opsin sequence, constructs were created that were up to 9-fold more stable than WT. Using cellular retinaldehyde-binding protein (CRALBP), we developed a quick means of assessing the stability of the green pigment. CRALBP testing also confirmed an additional 48-fold increase in pigment stability when varying the detergent used. These results suggest an efficient protocol for routine purification and stabilization of cone pigments that could be used for high-resolution determination of their structures, as well as for other studies.
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Affiliation(s)
- Timothy S. Owen
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 2109 Adelbert Road, Cleveland, Ohio 44106, United States
| | - David Salom
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 2109 Adelbert Road, Cleveland, Ohio 44106, United States
| | - Wenyu Sun
- Polgenix, Inc., Cleveland, Ohio 44106, United States
| | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 2109 Adelbert Road, Cleveland, Ohio 44106, United States
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30
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Yang D, Krois CR, Huang P, Wang J, Min J, Yoo HS, Deng Y, Napoli JL. Raldh1 promotes adiposity during adolescence independently of retinal signaling. PLoS One 2017; 12:e0187669. [PMID: 29095919 PMCID: PMC5667840 DOI: 10.1371/journal.pone.0187669] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 10/24/2017] [Indexed: 12/26/2022] Open
Abstract
All-trans-retinoic acid (RA) inhibits adipogenesis in established preadipocyte cell lines. Dosing pharmacological amounts of RA reduces weight gain in mice fed a high-fat diet, i.e. counteracts diet-induced obesity (DIO). The aldehyde dehydrogenase Raldh1 (Aldh1a1) functions as one of three enzymes that converts the retinol metabolite retinal into RA, and one of many proteins that contribute to RA homeostasis. Female Raldh1-ablated mice resist DIO. This phenotype contrasts with ablations of other enzymes and binding-proteins that maintain RA homeostasis, which gain adiposity. The phenotype observed prompted the conclusion that loss of Raldh1 causes an increase in adipose tissue retinal, and therefore, retinal functions independently of RA to prevent DIO. A second deduction proposed that low nM concentrations of RA stimulate adipogenesis, in contrast to higher concentrations. Using peer-reviewed LC/MS/MS assays developed and validated for quantifying tissue RA and retinal, we show that endogenous retinal and RA concentrations in adipose tissues from Raldh1-null mice do not correlate with the phenotype. Moreover, male Raldh1-null mice resist weight gain regardless of dietary fat content. Resistance to weight gain occurs during adolescence in both sexes. We show that RA concentrations as low as 1 nM, i.e. in the sub-physiological range, impair adipogenesis of embryonic fibroblasts from wild-type mice. Embryonic fibroblasts from Raldh1-null mice resist differentiating into adipocytes, but retain ability to generate RA. These fibroblasts remain sensitive to an RA receptor pan-agonist, and are not affected by an RA receptor pan-antagonist. Thus, the data do not support the hypothesis that retinal itself represses weight gain and adipogenesis independently of RA. Instead, the data indicate that Raldh1 functions as a retinal and atRA-independent promoter of adiposity during adolescence, and enhances adiposity through pre-adipocyte cell autonomous actions.
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Affiliation(s)
- Di Yang
- Graduate Program in Metabolic Biology, Nutritional Sciences and Toxicology, University of California, Berkeley, California, United States of America
| | - Charles R. Krois
- Graduate Program in Metabolic Biology, Nutritional Sciences and Toxicology, University of California, Berkeley, California, United States of America
| | - Priscilla Huang
- Graduate Program in Metabolic Biology, Nutritional Sciences and Toxicology, University of California, Berkeley, California, United States of America
| | - Jinshan Wang
- Graduate Program in Metabolic Biology, Nutritional Sciences and Toxicology, University of California, Berkeley, California, United States of America
| | - Jin Min
- Graduate Program in Metabolic Biology, Nutritional Sciences and Toxicology, University of California, Berkeley, California, United States of America
| | - Hong Sik Yoo
- Graduate Program in Metabolic Biology, Nutritional Sciences and Toxicology, University of California, Berkeley, California, United States of America
| | - Yinghua Deng
- Graduate Program in Metabolic Biology, Nutritional Sciences and Toxicology, University of California, Berkeley, California, United States of America
| | - Joseph L. Napoli
- Graduate Program in Metabolic Biology, Nutritional Sciences and Toxicology, University of California, Berkeley, California, United States of America
- * E-mail:
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31
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Malechka VV, Moiseyev G, Takahashi Y, Shin Y, Ma JX. Impaired Rhodopsin Generation in the Rat Model of Diabetic Retinopathy. Am J Pathol 2017; 187:2222-2231. [PMID: 28734946 PMCID: PMC5809515 DOI: 10.1016/j.ajpath.2017.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 06/14/2017] [Accepted: 06/19/2017] [Indexed: 12/11/2022]
Abstract
Diabetic retinopathy is a common complication of diabetes mellitus. Diabetic patients experience functional deficits in dark adaptation, contrast sensitivity, and color perception before microvascular pathologies become apparent. Herein, we evaluated early changes in neural retinal function and in retinoid metabolism in the eye in diabetes. Streptozotocin-induced diabetic rats showed decreased a- and b-wave amplitudes of scotopic and photopic electroretinography responses 4 months after diabetes induction compared to nondiabetic controls. Although Western blot analysis revealed no difference in opsin expression, rhodopsin content was decreased in diabetic retinas, as shown by a difference in absorbance. Consistently, levels of 11-cis-retinal, the chromophore for visual pigments, were significantly lower in diabetic retinas compared to those in controls, suggesting a retinoid deficiency. Among visual cycle proteins, interphotoreceptor retinoid-binding protein and stimulated by retinoic acid 6 protein showed significantly lower levels in diabetic rats than those in nondiabetic controls. Similarly, serum levels of retinol-binding protein 4 and retinoids were significantly lower in diabetic rats. Overall, these results suggest that retinoid metabolism in the eye is impaired in type 1 diabetes, which leads to deficient generation of visual pigments and neural retinal dysfunction in early diabetes.
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Affiliation(s)
- Volha V Malechka
- Department of Physiology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Gennadiy Moiseyev
- Department of Physiology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
| | - Yusuke Takahashi
- Department of Medicine, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Younghwa Shin
- Department of Physiology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Jian-Xing Ma
- Department of Physiology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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32
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Gong X, Marisiddaiah R, Rubin LP. Inhibition of pulmonary β-carotene 15, 15'-oxygenase expression by glucocorticoid involves PPARα. PLoS One 2017; 12:e0181466. [PMID: 28732066 PMCID: PMC5521778 DOI: 10.1371/journal.pone.0181466] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/30/2017] [Indexed: 01/19/2023] Open
Abstract
β-carotene 15,15'-oxygenase (BCO1) catalyzes the first step in the conversion of dietary provitamin A carotenoids to vitamin A. This enzyme is expressed in a variety of developing and adult tissues, suggesting that its activity may regulate local retinoid synthesis. Vitamin A and related compounds (retinoids) are critical regulators of lung epithelial development, integrity, and injury repair. A balance between the actions of retinoids and glucocorticoids (GCs) promotes normal lung development and, in particular, alveolarization. Alterations in this balance, including vitamin A deficiency and GC excess, contribute to the development of chronic lung disorders. Consequently, we investigated if GCs counteract retinoid effects in alveolar epithelial cells by mechanisms involving BCO1-dependent local vitamin A metabolism. We demonstrate that BCO1 is expressed in human fetal lung tissue and human alveolar epithelial-like A549 cells. Our results indicate A549 cells metabolize β-carotene to retinal and retinoic acid (RA). GCs exposure using dexamethasone (DEX) decreases BCO1 mRNA and protein levels in A549 cells and reduces BCO1 promoter activity via inhibiting peroxisome proliferator-activated receptor γ (PPARγ) DNA binding. DEX also induces expression of PPARα, which in turn most likely causes a decrease in PPARγ/RXRα heterodimer binding to the bco1 gene promoter and consequent inhibition of bco1 gene expression. PPARα knockdown with siRNA abolishes DEX-induced suppression of BCO1 expression, confirming the requirement for PPARα in this DEX-mediated BCO1 mechanism. Taken together, these findings provide the first evidence that GCs regulate vitamin A (retinoid) signaling via inhibition of bco1 gene expression in a PPARα-dependent manner. These results explicate novel aspects of local GC:retinoid interactions that may contribute to alveolar tissue remodeling in chronic lung diseases that affect children and, possibly, adults.
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Affiliation(s)
- Xiaoming Gong
- Department of Pediatrics, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
- * E-mail: (XG); (LPR)
| | - Raju Marisiddaiah
- All Children’s Research Institute, St. Petersburg, Florida, United States of America
| | - Lewis P. Rubin
- Department of Pediatrics, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
- * E-mail: (XG); (LPR)
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33
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Katayama K, Nonaka Y, Tsutsui K, Imai H, Kandori H. Spectral Tuning Mechanism of Primate Blue-sensitive Visual Pigment Elucidated by FTIR Spectroscopy. Sci Rep 2017; 7:4904. [PMID: 28687791 PMCID: PMC5501831 DOI: 10.1038/s41598-017-05177-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/24/2017] [Indexed: 11/17/2022] Open
Abstract
Protein-bound water molecules are essential for the structure and function of many membrane proteins, including G-protein-coupled receptors (GPCRs). Our prior work focused on studying the primate green- (MG) and red- (MR) sensitive visual pigments using low-temperature Fourier transform infrared (FTIR) spectroscopy, which revealed protein-bound waters in both visual pigments. Although the internal waters are located in the vicinity of both the retinal Schiff base and retinal β-ionone ring, only the latter showed differences between MG and MR, which suggests their role in color tuning. Here, we report FTIR spectra of primate blue-sensitive pigment (MB) in the entire mid-IR region, which reveal the presence of internal waters that possess unique water vibrational signals that are reminiscent of a water cluster. These vibrational signals of the waters are influenced by mutations at position Glu113 and Trp265 in Rh, which suggest that these waters are situated between these two residues. Because Tyr265 is the key residue for achieving the spectral blue-shift in λmax of MB, we propose that these waters are responsible for the increase in polarity toward the retinal Schiff base, which leads to the localization of the positive charge in the Schiff base and consequently causes the blue-shift of λmax.
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Affiliation(s)
- Kota Katayama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-855, Japan
| | - Yuki Nonaka
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
| | - Kei Tsutsui
- Primate Research Institute, Kyoto University, Inuyama, 484-8506, Japan
| | - Hiroo Imai
- Primate Research Institute, Kyoto University, Inuyama, 484-8506, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan.
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-855, Japan.
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34
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Abstract
Retinoic acid (RA) is converted from retinal by retinaldehyde dehydrogenases (RALDHs) and is an essential signaling molecule in embryonic and adult tissue. We previously reported that RALDH1 was produced in the rat anterior pituitary gland and hypothesized that RA was generated in the gland. Midkine (MK) is an RA-inducible growth factor, and MK production in the rat anterior pituitary gland was recently reported. However, the mechanism that regulates gene expression of MK in the pituitary gland has not been determined. To investigate regulation of MK production in the anterior pituitary gland, we analyzed changes in MK mRNA in cultured rat anterior pituitary cells. We identified MK-expressing cells by double-staining with in situ hybridization and immunohistochemical techniques for RALDH1. MK mRNA was expressed in RALDH1-producing cells in the anterior pituitary gland. Using isolated anterior pituitary cells of rats, we examined the effect of RA on gene expression of MK. Quantitative real-time PCR revealed that 72 h exposure to a concentration of 10-6 M of retinal and all-trans retinoic acid increased MK mRNA levels by about 2-fold. Moreover, the stimulatory effect of all-trans retinoic acid was mimicked by the RA receptor agonist Am80. This is the first report to show that RA is important in regulating MK expression in rat anterior pituitary gland.
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Affiliation(s)
- Rita Maliza
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Ken Fujiwara
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Morio Azuma
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Motoshi Kikuchi
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Tochigi, Japan
- Laboratory of Natural History, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Takashi Yashiro
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Tochigi, Japan
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35
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Abstract
Transplantation of retinal pigment epithelium (RPE) may have potential clinical application for the surgical treatment of RPE-specific retinal degeneration, including age-related macular degeneration. The feasibility of an RPE storage bank has been investigated by experimenting with transplantation using viable, cryopreserved RPE cells. Fresh and cultured fetal human and bovine RPE cells were cryopreserved in 90% fetal bovine serum containing 10% dimethyl sulfoxide. The viability of the cells before and after cryopreservation was evaluated by trypan blue dye exclusion test, microculture tetrazolium assay (MTA), tissue culture, and transplantation after cryopreservation. The origin of RPE cells before and after cryopreservation was assessed by immunocytochemistry, immunoblotting, and indirect ELISA of RPE-marker protein using cytokeratin for cultured fetal human RPE cells and by immunocytochemistry of cellular retinaldehyde-binding protein (CR-ALBP) for cultured bovine RPE cells. Freshly isolated and cryopreserved uncultured bovine RPE cells were transplanted by posterior transscleral approach into the subretinal spaces of adult albino rabbits and 23-day-old Royal College of Surgeons (RCS) rats with a 33 gauge Hamilton syringe. Following surgery, artificial retinal blebs were confirmed by fundus examination. Morphologic examination was performed postoperatively by light and electron microscopy in albino rabbits and by light microscopy in RCS rats up to 3 mo. Control subretinal injections using vehicle solution also were performed in RCS rats. Cultured fetal human and bovine RPE cells after cryopreservation were found to be viable, based on the results of trypan blue dye exclusion test, MTA, tissue culture, and transplantation. Expression and reexpression of cytokeratin intermediate filaments in cultured fetal human RPE were demonstrated by immunocytochemistry, immunoblotting, and indirect ELISA before and after cryopreservation. Immunocytochemistry of CRALBP before and after cryopreservation in uncultured bovine RPE cells disclosed expression and reexpression of RPE cell marker protein. No uncultured fetal human RPE cells showed proliferation in tissue culture after cryopreservation. In rabbits, light and electron microscopy disclosed xenografted RPE cells residing on Bruch's membrane of the host retina. No sign of graft vs. host reaction was observed. No morphologic difference was noted between the fresh and 10-day-old cryopreserved RPE cells in situ following transplantation at day 25. In RCS rats, subretinal injection of 3-wk-old cryopreserved bovine RPE cells partially rescued photoreceptor cells locally at the transplanted area observed at 3 mo postoperatively. The retinal photoreceptors at the inferior hemisphere of the transplanted eye and the eye injected with vehicle solution showed no rescue effect. We found that cryopreserved cultured fetal human RPE cells and uncultured and cultured bovine RPE cells can be used for RPE transplantation studies. The ability to create an RPE storage bank as a source of donor cells may result in several clinical advantages.
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Affiliation(s)
- Y K Durlu
- Department of Ophthalmology, Tohoku University School of Medicine, Miyagi, Japan
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Tomobe K, Yamamoto E, Kholmurodov K, Yasuoka K. Water permeation through the internal water pathway in activated GPCR rhodopsin. PLoS One 2017; 12:e0176876. [PMID: 28493967 PMCID: PMC5426653 DOI: 10.1371/journal.pone.0176876] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 04/18/2017] [Indexed: 12/13/2022] Open
Abstract
Rhodopsin is a light-driven G-protein-coupled receptor that mediates signal transduction in eyes. Internal water molecules mediate activation of the receptor in a rhodopsin cascade reaction and contribute to conformational stability of the receptor. However, it remains unclear how internal water molecules exchange between the bulk and protein inside, in particular through a putative solvent pore on the cytoplasmic. Using all-atom molecular dynamics simulations, we identified the solvent pore on cytoplasmic side in both the Meta II state and the Opsin. On the other hand, the solvent pore does not exist in the dark-adapted rhodopsin. We revealed two characteristic narrow regions located within the solvent pore in the Meta II state. The narrow regions distinguish bulk and the internal hydration sites, one of which is adjacent to the conserved structural motif "NPxxY". Water molecules in the solvent pore diffuse by pushing or sometimes jumping a preceding water molecule due to the geometry of the solvent pore. These findings revealed a total water flux between the bulk and the protein inside in the Meta II state, and suggested that these pathways provide water molecules to the crucial sites of the activated rhodopsin.
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Affiliation(s)
- Katsufumi Tomobe
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Eiji Yamamoto
- Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Kholmirzo Kholmurodov
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, 141980, Russia
- Dubna State University, Dubna, 141980, Russia
| | - Kenji Yasuoka
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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Abstract
The visual system produces visual chromophore, 11-cis-retinal from dietary vitamin A, all-trans-retinol making this vitamin essential for retinal health and function. These metabolic events are mediated by a sequential biochemical process called the visual cycle. Retinol dehydrogenases (RDHs) are responsible for two reactions in the visual cycle performed in retinal pigmented epithelial (RPE) cells, photoreceptor cells and Müller cells in the retina. RDHs in the RPE function as 11-cis-RDHs, which oxidize 11-cis-retinol to 11-cis-retinal in vivo. RDHs in rod photoreceptor cells in the retina work as all-trans-RDHs, which reduce all-trans-retinal to all-trans-retinol. Dysfunction of RDHs can cause inherited retinal diseases in humans. To facilitate further understanding of human diseases, mouse models of RDHs-related diseases have been carefully examined and have revealed the physiological contribution of specific RDHs to visual cycle function and overall retinal health. Herein we describe the function of RDHs in the RPE and the retina, particularly in rod photoreceptor cells, their regulatory properties for retinoid homeostasis and future therapeutic strategy for treatment of retinal diseases.
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Affiliation(s)
- Bhubanananda Sahu
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4965, USA.
| | - Akiko Maeda
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4965, USA.
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106-4965, USA.
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Wang J, Westenskow PD, Fang M, Friedlander M, Siuzdak G. Quantitative metabolomics of photoreceptor degeneration and the effects of stem cell-derived retinal pigment epithelium transplantation. Philos Trans A Math Phys Eng Sci 2016; 374:rsta.2015.0376. [PMID: 27644974 PMCID: PMC5031641 DOI: 10.1098/rsta.2015.0376] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/17/2016] [Indexed: 06/06/2023]
Abstract
Photoreceptor degeneration is characteristic of vision-threatening diseases including age-related macular degeneration. Photoreceptors are metabolically demanding cells in the retina, but specific details about their metabolic behaviours are unresolved. The quantitative metabolomics of retinal degeneration could provide valuable insights and inform future therapies. Here, we determined the metabolomic 'fingerprint' of healthy and dystrophic retinas in rat models using optimized metabolite extraction techniques. A number of classes of metabolites were consistently dysregulated during degeneration: vitamin A analogues, fatty acid amides, long-chain polyunsaturated fatty acids, acyl carnitines and several phospholipid species. For the first time, a distinct temporal trend of several important metabolites including DHA (4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoic acid), all-trans-retinal and its toxic end-product N-retinyl-N-retinylidene-ethanolamine were observed between healthy and dystrophic retinas. In this study, metabolomics was further used to determine the temporal effects of the therapeutic intervention of grafting stem cell-derived retinal pigment epithelium (RPE) in dystrophic retinas, which significantly prevented photoreceptor atrophy in our previous studies. The result revealed that lipid levels such as phosphatidylethanolamine in eyes were restored in those animals receiving the RPE grafts. In conclusion, this study provides insight into the metabolomics of retinal degeneration, and further understanding of the efficacy of RPE transplantation.This article is part of the themed issue 'Quantitative mass spectrometry'.
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Affiliation(s)
- Junhua Wang
- Center for Metabolomics, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Peter D Westenskow
- Department of Cell and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA The Lowy Medical Research Institute, 3366 N. Torrey Pines Court, Suite 300, La Jolla, CA 92037, USA
| | - Mingliang Fang
- Center for Metabolomics, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA School of Civil and Environmental Engineering, Nanyang Technological University, Singapore
| | - Martin Friedlander
- Department of Cell and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Gary Siuzdak
- Center for Metabolomics, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA Departments of Chemistry, Molecular and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Thompson CL, Selby CP, Van Gelder RN, Blaner WS, Lee J, Quadro L, Lai K, Gottesman ME, Sancar A. Effect of Vitamin A Depletion on Nonvisual Phototransduction Pathways in Cryptochromeless Mice. J Biol Rhythms 2016; 19:504-17. [PMID: 15523112 DOI: 10.1177/0748730404270519] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mice exhibit multiple nonvisual responses to light, including 1) photoentrainment of circadian rhythm; 2) “masking,” which refers to the acute effect of light on behavior, either negative (activity suppressing) or positive (activity inducing); and 3) pupillary constriction. In mammals, the eye is the sole photosensory organ for these responses, and it contains only 2 known classes of pigments: opsins and cryptochromes. No individual opsin or cryptochrome gene is essential for circadian photoreception, gene photoinduction, or masking. Previously, the authors found that mice lacking retinol-binding protein, in which dietary depletion of ocular retinaldehyde can be achieved, had normal light signaling to the SCN, as determined by per gene photoinduction. In the present study, the authors analyzed phototransduction to the SCN in vitamin A-replete and vitamin A-depleted rbp-/- and rbp-/-cry1-/-cry2-/- mice using molecular and behavioral end points. They found that vitamin A-depleted rbp-/- mice exhibit either normal photoentrainment or become diurnal. In contrast, while vitamin A-replete rbp-/-cry1-/-cry2-/- mice are light responsive (with reduced sensitivity), vitamin A-depleted rbp-/-cry1-/-cry2-/- mice, which presumably lack functional opsins and cryptochromes, lose most behavioral and molecular responses to light. These data demonstrate that both cryptochromes and opsins regulate nonvisual photoresponses.
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Affiliation(s)
- Carol L Thompson
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
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Becker EA, Yao AI, Seitzer PM, Kind T, Wang T, Eigenheer R, Shao KSY, Yarov-Yarovoy V, Facciotti MT. A Large and Phylogenetically Diverse Class of Type 1 Opsins Lacking a Canonical Retinal Binding Site. PLoS One 2016; 11:e0156543. [PMID: 27327432 PMCID: PMC4915679 DOI: 10.1371/journal.pone.0156543] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/19/2016] [Indexed: 11/24/2022] Open
Abstract
Opsins are photosensitive proteins catalyzing light-dependent processes across the tree of life. For both microbial (type 1) and metazoan (type 2) opsins, photosensing depends upon covalent interaction between a retinal chromophore and a conserved lysine residue. Despite recent discoveries of potential opsin homologs lacking this residue, phylogenetic dispersal and functional significance of these abnormal sequences have not yet been investigated. We report discovery of a large group of putatively non-retinal binding opsins, present in a number of fungal and microbial genomes and comprising nearly 30% of opsins in the Halobacteriacea, a model clade for opsin photobiology. We report phylogenetic analyses, structural modeling, genomic context analysis and biochemistry, to describe the evolutionary relationship of these recently described proteins with other opsins, show that they are expressed and do not bind retinal in a canonical manner. Given these data, we propose a hypothesis that these abnormal opsin homologs may represent a novel family of sensory opsins which may be involved in taxis response to one or more non-light stimuli. If true, this finding would challenge our current understanding of microbial opsins as a light-specific sensory family, and provides a potential analogy with the highly diverse signaling capabilities of the eukaryotic G-protein coupled receptors (GPCRs), of which metazoan type 2 opsins are a light-specific sub-clade.
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Affiliation(s)
- Erin A. Becker
- Genome Center, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
- Microbiology Graduate Group, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
| | - Andrew I. Yao
- Genome Center, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
- Department of Biomedical Engineering, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
| | - Phillip M. Seitzer
- Genome Center, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
- Department of Biomedical Engineering, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
- Proteome Software, 1340 SW Bertha Blvd., Portland, Oregon, United States of America
| | - Tobias Kind
- Genome Center, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
| | - Ting Wang
- Genome Center, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
| | - Rich Eigenheer
- California Department of Food and Agriculture, 1220 N St., Sacramento, CA, 95814, United States of America
| | - Katie S. Y. Shao
- William’s College, 880 Main St., Williamstown, MA, 01267, United States of America
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
| | - Marc T. Facciotti
- Genome Center, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
- Microbiology Graduate Group, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
- Department of Biomedical Engineering, One Shields Ave., University of California Davis, Davis, CA, 95616, United States of America
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Sato K, Yamashita T, Haruki Y, Ohuchi H, Kinoshita M, Shichida Y. Two UV-Sensitive Photoreceptor Proteins, Opn5m and Opn5m2 in Ray-Finned Fish with Distinct Molecular Properties and Broad Distribution in the Retina and Brain. PLoS One 2016; 11:e0155339. [PMID: 27167972 PMCID: PMC4864311 DOI: 10.1371/journal.pone.0155339] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/27/2016] [Indexed: 12/02/2022] Open
Abstract
Opn5 is a group within the opsin family of proteins that is responsible for visual and non-visual photoreception in animals. It consists of several subgroups, including Opn5m, the only subgroup containing members found in most vertebrates, including mammals. In addition, recent genomic information has revealed that some ray-finned fishes carry paralogous genes of Opn5m while other fishes have no such genes. Here, we report the molecular properties of the opsin now called Opn5m2 and its distributions in both the retina and brain. Like Opn5m, Opn5m2 exhibits UV light-sensitivity when binding to 11-cis-retinal and forms a stable active state that couples with Gi subtype of G protein. However, Opn5m2 does not bind all-trans-retinal and exhibits exclusive binding to 11-cis-retinal, whereas many bistable opsins, including fish Opn5m, can bind directly to all-trans-retinal as well as 11-cis-retinal. Because medaka fish has lost the Opn5m2 gene from its genome, we compared the tissue distribution patterns of Opn5m in medaka fish, zebrafish, and spotted gar, in addition to the distribution patterns of Opn5m2 in zebrafish and spotted gar. Opn5m expression levels showed a gradient along the dorsal–ventral axis of the retina, and preferential expression was observed in the ventral retina in the three fishes. The levels of Opn5m2 showed a similar gradient with preferential expression observed in the dorsal retina. Opn5m expression was relatively abundant in the inner region of the inner nuclear layer, while Opn5m2 was expressed in the outer edge of the inner nuclear layer. Additionally, we could detect Opn5m expression in several brain regions, including the hypothalamus, of these fish species. Opn5m2 expression could not be detected in zebrafish brain, but was clearly observed in limited brain regions of spotted gar. These results suggest that ray-finned fishes can generally utilize UV light information for non-image-forming photoreception in a wide range of cells in the retina and brain.
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Affiliation(s)
- Keita Sato
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Takahiro Yamashita
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Yoshihiro Haruki
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Hideyo Ohuchi
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Masato Kinoshita
- Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yoshinori Shichida
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
- * E-mail:
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Štambergová H, Zemanová L, Lundová T, Malčeková B, Skarka A, Šafr M, Wsól V. Human DHRS7, promising enzyme in metabolism of steroids and retinoids? J Steroid Biochem Mol Biol 2016; 155:112-9. [PMID: 26466768 DOI: 10.1016/j.jsbmb.2015.09.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/25/2015] [Accepted: 09/28/2015] [Indexed: 01/25/2023]
Abstract
The metabolism of steroids and retinoids has been studied in detail for a long time, as these compounds are involved in a broad spectrum of physiological processes. Many enzymes participating in the conversion of such compounds are members of the short-chain dehydrogenase/reductase (SDR) superfamily. Despite great effort, there still remain a number of poorly characterized SDR proteins. According to various bioinformatics predictions, many of these proteins may play a role in the metabolism of steroids and retinoids. Dehydrogenase/reductase (SDR family) member 7 (DHRS7) is one such protein. In a previous study, we determined DHRS7 to be an integral membrane protein of the endoplasmic reticulum facing the lumen which has shown at least in vitro NADPH-dependent reducing activity toward several eobiotics and xenobiotics bearing a carbonyl moiety. In the present paper pure DHRS7 was used for a more detailed study of both substrate screening and an analysis of kinetics parameters of the physiologically important substrates androstene-3,17-dione, cortisone and all-trans-retinal. Expression patterns of DHRS7 at the mRNA as well as protein level were determined in a panel of various human tissue samples, a procedure that has enabled the first estimation of the possible biological function of this enzyme. DHRS7 is expressed in tissues such as prostate, adrenal glands, liver or intestine, where its activity could be well exploited. Preliminary indications show that DHRS7 exhibits dual substrate specificity recognizing not only steroids but also retinoids as potential substrates and could be important in the metabolism of these signalling molecules.
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Affiliation(s)
- Hana Štambergová
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Heyrovského 1203, CZ-50005 Hradec Králové, Czech Republic.
| | - Lucie Zemanová
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Heyrovského 1203, CZ-50005 Hradec Králové, Czech Republic.
| | - Tereza Lundová
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Heyrovského 1203, CZ-50005 Hradec Králové, Czech Republic.
| | - Beata Malčeková
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Heyrovského 1203, CZ-50005 Hradec Králové, Czech Republic.
| | - Adam Skarka
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Heyrovského 1203, CZ-50005 Hradec Králové, Czech Republic.
| | - Miroslav Šafr
- Institute of Legal Medicine, Faculty of Medicine in Hradec Králové, Charles University in Prague and University Hospital in Hradec Králové, Sokolská 581, 50005 Hradec Králové, Czech Republic.
| | - Vladimír Wsól
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Heyrovského 1203, CZ-50005 Hradec Králové, Czech Republic.
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Abstract
Opn3/TMT opsins belong to one of the opsin groups with vertebrate visual and non-visual opsins, and are widely distributed in eyes, brains and other internal organs in various vertebrates and invertebrates. Vertebrate Opn3/TMT opsins are further classified into four groups on the basis of their amino acid identities. However, there is limited information about molecular properties of these groups, due to the difficulty in preparing the recombinant proteins. Here, we successfully expressed recombinant proteins of TMT1 and TMT2 opsins of medaka fish (Oryzias latipes) in cultured cells and characterized their molecular properties. Spectroscopic and biochemical studies demonstrated that TMT1 and TMT2 opsins functioned as blue light-sensitive Gi/Go-coupled receptors, but exhibited spectral properties and photo-convertibility of the active state different from each other. TMT1 opsin forms a visible light-absorbing active state containing all-trans-retinal, which can be photo-converted to 7-cis- and 9-cis-retinal states in addition to the original 11-cis-retinal state. In contrast, the active state of TMT2 opsin is a UV light-absorbing state having all-trans-retinal and does not photo-convert to any other state, including the original 11-cis-retinal state. Thus, TMT opsins are diversified so as to form a different type of active state, which may be responsible for their different functions.
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Affiliation(s)
- Kazumi Sakai
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Takahiro Yamashita
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Yasushi Imamoto
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Yoshinori Shichida
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
- * E-mail:
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Giménez-Dejoz J, Kolář MH, Ruiz FX, Crespo I, Cousido-Siah A, Podjarny A, Barski OA, Fanfrlík J, Parés X, Farrés J, Porté S. Substrate Specificity, Inhibitor Selectivity and Structure-Function Relationships of Aldo-Keto Reductase 1B15: A Novel Human Retinaldehyde Reductase. PLoS One 2015; 10:e0134506. [PMID: 26222439 PMCID: PMC4519324 DOI: 10.1371/journal.pone.0134506] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/09/2015] [Indexed: 02/02/2023] Open
Abstract
Human aldo-keto reductase 1B15 (AKR1B15) is a newly discovered enzyme which shares 92% amino acid sequence identity with AKR1B10. While AKR1B10 is a well characterized enzyme with high retinaldehyde reductase activity, involved in the development of several cancer types, the enzymatic activity and physiological role of AKR1B15 are still poorly known. Here, the purified recombinant enzyme has been subjected to substrate specificity characterization, kinetic analysis and inhibitor screening, combined with structural modeling. AKR1B15 is active towards a variety of carbonyl substrates, including retinoids, with lower kcat and Km values than AKR1B10. In contrast to AKR1B10, which strongly prefers all-trans-retinaldehyde, AKR1B15 exhibits superior catalytic efficiency with 9-cis-retinaldehyde, the best substrate found for this enzyme. With ketone and dicarbonyl substrates, AKR1B15 also shows higher catalytic activity than AKR1B10. Several typical AKR inhibitors do not significantly affect AKR1B15 activity. Amino acid substitutions clustered in loops A and C result in a smaller, more hydrophobic and more rigid active site in AKR1B15 compared with the AKR1B10 pocket, consistent with distinct substrate specificity and narrower inhibitor selectivity for AKR1B15.
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Affiliation(s)
- Joan Giménez-Dejoz
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Michal H. Kolář
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Institute of Neuroscience and Medicine (INM-9) and Institute for Advanced Simulation (IAS-5), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Francesc X. Ruiz
- Department of Integrative Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire-Centre de Biologie Intégrative, CNRS, INSERM, UdS, Illkirch CEDEX, France
| | - Isidro Crespo
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Alexandra Cousido-Siah
- Department of Integrative Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire-Centre de Biologie Intégrative, CNRS, INSERM, UdS, Illkirch CEDEX, France
| | - Alberto Podjarny
- Department of Integrative Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire-Centre de Biologie Intégrative, CNRS, INSERM, UdS, Illkirch CEDEX, France
| | - Oleg A. Barski
- Diabetes and Obesity Center, School of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Jindřich Fanfrlík
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Xavier Parés
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Jaume Farrés
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Sergio Porté
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
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Takemoto M, Kato HE, Koyama M, Ito J, Kamiya M, Hayashi S, Maturana AD, Deisseroth K, Ishitani R, Nureki O. Molecular Dynamics of Channelrhodopsin at the Early Stages of Channel Opening. PLoS One 2015; 10:e0131094. [PMID: 26114863 PMCID: PMC4482709 DOI: 10.1371/journal.pone.0131094] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 05/28/2015] [Indexed: 11/25/2022] Open
Abstract
Channelrhodopsin (ChR) is a light-gated cation channel that responds to blue light. Since ChR can be readily expressed in specific neurons to precisely control their activities by light, it has become a powerful tool in neuroscience. Although the recently solved crystal structure of a chimeric ChR, C1C2, provided the structural basis for ChR, our understanding of the molecular mechanism of ChR still remains limited. Here we performed electrophysiological analyses and all-atom molecular dynamics (MD) simulations, to investigate the importance of the intracellular and central constrictions of the ion conducting pore observed in the crystal structure of C1C2. Our electrophysiological analysis revealed that two glutamate residues, Glu122 and Glu129, in the intracellular and central constrictions, respectively, should be deprotonated in the photocycle. The simulation results suggested that the deprotonation of Glu129 in the central constriction leads to ion leakage in the ground state, and implied that the protonation of Glu129 is important for preventing ion leakage in the ground state. Moreover, we modeled the 13-cis retinal bound; i.e., activated C1C2, and performed MD simulations to investigate the conformational changes in the early stage of the photocycle. Our simulations suggested that retinal photoisomerization induces the conformational change toward channel opening, including the movements of TM6, TM7 and TM2. These insights into the dynamics of the ground states and the early photocycle stages enhance our understanding of the channel function of ChR.
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Affiliation(s)
- Mizuki Takemoto
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113–0033, Japan
| | - Hideaki E. Kato
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113–0033, Japan
| | - Michio Koyama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113–0033, Japan
| | - Jumpei Ito
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464–8601, Japan
| | - Motoshi Kamiya
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606–8502, Japan
| | - Shigehiko Hayashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606–8502, Japan
| | - Andrés D. Maturana
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464–8601, Japan
| | - Karl Deisseroth
- Department of Bioengineering and Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, United States of America
| | - Ryuichiro Ishitani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113–0033, Japan
- * E-mail: (ON); (RI)
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113–0033, Japan
- * E-mail: (ON); (RI)
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Zhang J, Kiser PD, Badiee M, Palczewska G, Dong Z, Golczak M, Tochtrop GP, Palczewski K. Molecular pharmacodynamics of emixustat in protection against retinal degeneration. J Clin Invest 2015; 125:2781-94. [PMID: 26075817 DOI: 10.1172/jci80950] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 05/12/2015] [Indexed: 01/24/2023] Open
Abstract
Emixustat is a visual cycle modulator that has entered clinical trials as a treatment for age-related macular degeneration (AMD). This molecule has been proposed to inhibit the visual cycle isomerase RPE65, thereby slowing regeneration of 11-cis-retinal and reducing production of retinaldehyde condensation byproducts that may be involved in AMD pathology. Previously, we reported that all-trans-retinal (atRAL) is directly cytotoxic and that certain primary amine compounds that transiently sequester atRAL via Schiff base formation ameliorate retinal degeneration. Here, we have shown that emixustat stereoselectively inhibits RPE65 by direct active site binding. However, we detected the presence of emixustat-atRAL Schiff base conjugates, indicating that emixustat also acts as a retinal scavenger, which may contribute to its therapeutic effects. Using agents that lack either RPE65 inhibitory activity or the capacity to sequester atRAL, we assessed the relative importance of these 2 modes of action in protection against retinal phototoxicity in mice. The atRAL sequestrant QEA-B-001-NH2 conferred protection against phototoxicity without inhibiting RPE65, whereas an emixustat derivative incapable of atRAL sequestration was minimally protective, despite direct inhibition of RPE65. These data indicate that atRAL sequestration is an essential mechanism underlying the protective effects of emixustat and related compounds against retinal phototoxicity. Moreover, atRAL sequestration should be considered in the design of next-generation visual cycle modulators.
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Kaylor JJ, Radu RA, Bischoff N, Makshanoff J, Hu J, Lloyd M, Eddington S, Bianconi T, Bok D, Travis GH. Diacylglycerol O-acyltransferase type-1 synthesizes retinyl esters in the retina and retinal pigment epithelium. PLoS One 2015; 10:e0125921. [PMID: 25974161 PMCID: PMC4431840 DOI: 10.1371/journal.pone.0125921] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/13/2015] [Indexed: 11/19/2022] Open
Abstract
Retinyl esters represent an insoluble storage form of vitamin A and are substrates for the retinoid isomerase (Rpe65) in cells of the retinal pigment epithelium (RPE). The major retinyl-ester synthase in RPE cells is lecithin:retinol acyl-transferase (LRAT). A second palmitoyl coenzyme A-dependent retinyl-ester synthase activity has been observed in RPE homogenates but the protein responsible has not been identified. Here we show that diacylglycerol O-acyltransferase-1 (DGAT1) is expressed in multiple cells of the retina including RPE and Müller glial cells. DGAT1 catalyzes the synthesis of retinyl esters from multiple retinol isomers with similar catalytic efficiencies. Loss of DGAT1 in dgat1 -/- mice has no effect on retinal anatomy or the ultrastructure of photoreceptor outer-segments (OS) and RPE cells. Levels of visual chromophore in dgat1 -/- mice were also normal. However, the normal build-up of all-trans-retinyl esters (all-trans-RE’s) in the RPE during the first hour after a deep photobleach of visual pigments in the retina was not seen in dgat1 -/- mice. Further, total retinyl-ester synthase activity was reduced in both dgat1 -/- retina and RPE.
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Affiliation(s)
- Joanna J. Kaylor
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
| | - Roxana A. Radu
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Nicholas Bischoff
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jacob Makshanoff
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jane Hu
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Marcia Lloyd
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Shannan Eddington
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Tran Bianconi
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Dean Bok
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Neurobiology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Gabriel H. Travis
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, United States of America
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Singh S, Arcaroli J, Thompson DC, Messersmith W, Vasiliou V. Acetaldehyde and retinaldehyde-metabolizing enzymes in colon and pancreatic cancers. Adv Exp Med Biol 2015; 815:281-94. [PMID: 25427913 DOI: 10.1007/978-3-319-09614-8_16] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Colorectal cancer (CRC) and pancreatic cancer are two very significant contributors to cancer-related deaths. Chronic alcohol consumption is an important risk factor for these cancers. Ethanol is oxidized primarily by alcohol dehydrogenases to acetaldehyde, an agent capable of initiating tumors by forming adducts with proteins and DNA. Acetaldehyde is metabolized by ALDH2, ALDH1B1, and ALDH1A1 to acetate. Retinoic acid (RA) is required for cellular differentiation and is known to arrest tumor development. RA is synthesized from retinaldehyde by the retinaldehyde dehydrogenases, specifically ALDH1A1, ALDH1A2, ALDH1A3, and ALDH8A1. By eliminating acetaldehyde and generating RA, ALDHs can play a crucial regulatory role in the initiation and progression of cancers. ALDH1 catalytic activity has been used as a biomarker to identify and isolate normal and cancer stem cells; its presence in a tumor is associated with poor prognosis in colon and pancreatic cancer. In summary, these ALDHs are not only biomarkers for CRC and pancreatic cancer but also play important mechanistic role in cancer initiation, progression, and eventual prognosis.
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Affiliation(s)
- S Singh
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Mail Stop C238-P20, 12850 E Montview Blvd, Aurora, CO, 80045, USA
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Zhang M, Liu C, Hu MY, Zhang J, Xu P, Li F, Zhong ZY, Liu L, Liu XD. High-fat diet enhanced retinal dehydrogenase activity, but suppressed retinol dehydrogenase activity in liver of rats. J Pharmacol Sci 2015; 127:430-8. [PMID: 25953270 DOI: 10.1016/j.jphs.2015.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 02/28/2015] [Accepted: 03/02/2015] [Indexed: 01/26/2023] Open
Abstract
Evidence has shown that hyperlipidemia is associated with retinoid dyshomeostasis. In liver, retinol is mainly oxidized to retinal by retinol dehydrogenases (RDHs) and alcohol dehydrogenases (ADHs), further converted to retinoic acid by retinal dehydrogenases (RALDHs). The aim of this study was to investigate whether high-fat diet (HFD) induced hyperlipidemia affected activity and expression of hepatic ADHs/RDHs and RALDHs in rats. Results showed that retinol levels in liver, kidney and adipose tissue of HFD rats were significantly increased, while plasma retinol and hepatic retinal levels were markedly decreased. HFD rats exhibited significantly downregulated hepatic ADHs/RDHs activity and Adh1, Rdh10 and Dhrs9 expression. Oppositely, hepatic RALDHs activity and Raldh1 expression were upregulated in HFD rats. In HepG2 cells, treatment of HFD rat serum inhibited ADHs/RDHs activity and induced RALDHs activity. Among the tested abnormally altered components in HFD rat serum, cholesterol reduced ADHs/RDHs activity and RDH10 expression, while induced RALDHs activity and RALDH1 expression in HepG2 cells. Contrary to the effect of cholesterol, cholesterol-lowering agent pravastatin upregulated ADHs/RDHs activity and RDH10 expression, while suppressed RALDHs activity and RALDH1 expression. In conclusion, hyperlipidemia oppositely altered activity and expression of hepatic ADHs/RDHs and RALDHs, which is partially due to the elevated cholesterol levels.
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Affiliation(s)
- Mian Zhang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Nanjing 210009, PR China
| | - Can Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Nanjing 210009, PR China
| | - Meng-yue Hu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Nanjing 210009, PR China
| | - Ji Zhang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Nanjing 210009, PR China
| | - Ping Xu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Nanjing 210009, PR China
| | - Feng Li
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Nanjing 210009, PR China
| | - Ze-yu Zhong
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Nanjing 210009, PR China
| | - Li Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Nanjing 210009, PR China
| | - Xiao-dong Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Nanjing 210009, PR China.
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Nossoni Z, Assar Z, Yapici I, Nosrati M, Wang W, Berbasova T, Vasileiou C, Borhan B, Geiger J. Structures of holo wild-type human cellular retinol-binding protein II (hCRBPII) bound to retinol and retinal. Acta Crystallogr D Biol Crystallogr 2014; 70:3226-32. [PMID: 25478840 PMCID: PMC4257620 DOI: 10.1107/s1399004714023839] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 10/29/2014] [Indexed: 11/10/2022]
Abstract
Cellular retinol-binding proteins (CRBPs) I and II, which are members of the intracellular lipid-binding protein (iLBP) family, are retinoid chaperones that are responsible for the intracellular transport and delivery of both retinol and retinal. Although structures of retinol-bound CRBPI and CRBPII are known, no structure of a retinal-bound CRBP has been reported. In addition, the retinol-bound human CRBPII (hCRBPII) structure shows partial occupancy of a noncanonical conformation of retinol in the binding pocket. Here, the structure of retinal-bound hCRBPII and the structure of retinol-bound hCRBPII with retinol fully occupying the binding pocket are reported. It is further shown that the retinoid derivative seen in both the zebrafish CRBP and the hCRBPII structures is likely to be the product of flux-dependent and wavelength-dependent X-ray damage during data collection. The structures of retinoid-bound CRBPs are compared and contrasted, and rationales for the differences in binding affinities for retinal and retinol are provided.
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Affiliation(s)
- Zahra Nossoni
- Department of Chemistry, Michigan State University, East Lansing, MI 48864, USA
| | - Zahra Assar
- Department of Chemistry, Michigan State University, East Lansing, MI 48864, USA
| | - Ipek Yapici
- Department of Chemistry, Michigan State University, East Lansing, MI 48864, USA
| | - Meisam Nosrati
- Department of Chemistry, Michigan State University, East Lansing, MI 48864, USA
| | - Wenjing Wang
- Department of Chemistry, Michigan State University, East Lansing, MI 48864, USA
| | - Tetyana Berbasova
- Department of Chemistry, Michigan State University, East Lansing, MI 48864, USA
| | - Chrysoula Vasileiou
- Department of Chemistry, Michigan State University, East Lansing, MI 48864, USA
| | - Babak Borhan
- Department of Chemistry, Michigan State University, East Lansing, MI 48864, USA
| | - James Geiger
- Department of Chemistry, Michigan State University, East Lansing, MI 48864, USA
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