151
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Navidi M, Yadav S, Struts AV, Brown MF, Nesnas N. Synthesis of 9-CD 3-9- cis-Retinal Cofactor of Isorhodopsin. Tetrahedron Lett 2018; 59:4521-4524. [PMID: 30692701 DOI: 10.1016/j.tetlet.2018.11.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We report the synthesis of 9-CD3-9-cis-retinal via a six-step procedure from β-ionone. The steps involve an initial deuteration of the methyl ketone of β-ionone followed by two consecutive Horner-Wadsworth-Emmons (HWE) coupling reactions and their corresponding DIBAL reductions. A final oxidation of the allylic alcohol of the retinol leads to the target compound. This deuterium labeled retinoid is an important cofactor for studying protein-retinoid interactions in isorhodopsin.
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Affiliation(s)
- Mozhgan Navidi
- Department of Biomedical & Chemical Engineering & Sciences, Florida Institute of Technology, Melbourne, Florida 32901, USA
| | - Shreya Yadav
- Department of Biomedical & Chemical Engineering & Sciences, Florida Institute of Technology, Melbourne, Florida 32901, USA
| | - Andrey V Struts
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA
| | - Michael F Brown
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA
| | - Nasri Nesnas
- Department of Biomedical & Chemical Engineering & Sciences, Florida Institute of Technology, Melbourne, Florida 32901, USA
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152
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Structural biology of 11- cis-retinaldehyde production in the classical visual cycle. Biochem J 2018; 475:3171-3188. [PMID: 30352831 DOI: 10.1042/bcj20180193] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/20/2018] [Accepted: 09/26/2018] [Indexed: 12/21/2022]
Abstract
The vitamin A derivative 11-cis-retinaldehyde plays a pivotal role in vertebrate vision by serving as the chromophore of rod and cone visual pigments. In the initial step of vision, a photon is absorbed by this chromophore resulting in its isomerization to an all-trans state and consequent activation of the visual pigment and phototransduction cascade. Spent chromophore is released from the pigments through hydrolysis. Subsequent photon detection requires the delivery of regenerated 11-cis-retinaldehyde to the visual pigment. This trans-cis conversion is achieved through a process known as the visual cycle. In this review, we will discuss the enzymes, binding proteins and transporters that enable the visual pigment renewal process with a focus on advances made during the past decade in our understanding of their structural biology.
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153
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Baker CK, Flannery JG. Innovative Optogenetic Strategies for Vision Restoration. Front Cell Neurosci 2018; 12:316. [PMID: 30297985 PMCID: PMC6160748 DOI: 10.3389/fncel.2018.00316] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/30/2018] [Indexed: 12/27/2022] Open
Abstract
The advent of optogenetics has ushered in a new era in neuroscience where spatiotemporal control of neurons is possible through light application. These tools used to study neural circuits can also be used therapeutically to restore vision. In order to recapitulate the broad spectral and light sensitivities along with high temporal sensitivity found in human vision, researchers have identified and developed new optogenetic tools. There are two major kinds of optogenetic effectors employed in vision restoration: ion channels and G-protein coupled receptors (GPCRs). Ion channel based optogenetic therapies require high intensity light that can be unsafe at lower wavelengths, so work has been done to expand and red-shift the excitation spectra of these channels. Light activatable GPCRs are much more sensitive to light than their ion channel counterparts but are slower kinetically in terms of both activation and inactivation. This review article examines the latest optogenetic ion channel and GPCR candidates for vision restoration based on light and temporal sensitivity.
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Affiliation(s)
- Cameron K. Baker
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - John G. Flannery
- School of Optometry, University of California, Berkeley, Berkeley, CA, United States
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154
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Examining the Role of Cone-expressed RPE65 in Mouse Cone Function. Sci Rep 2018; 8:14201. [PMID: 30242264 PMCID: PMC6155087 DOI: 10.1038/s41598-018-32667-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 09/13/2018] [Indexed: 11/08/2022] Open
Abstract
Efficient chromophore supply is paramount for the continuous function of vertebrate cone photoreceptors. It is well established that isomerization of all-trans- to 11-cis- retinoid in the retinal pigmented epithelium by RPE65 is a key reaction in this process. Mutations in RPE65 result in a disrupted chromophore supply, retinal degeneration, and blindness. Interestingly, RPE65 has recently been found to also be expressed in cone photoreceptors in several species, including mouse and human. However, the functional role of cone-expressed RPE65 has remained unknown. Here, we used loss and gain of function approaches to investigate this issue. First, we compared the function of cones from control and RPE65-deficient mice. Although we found that deletion of RPE65 partially suppressed cone dark adaptation, the interpretation of this result was complicated by the abnormal cone structure and function caused by the chromophore deficiency in the absence of RPE65 in the pigmented epithelium. As an alternative approach, we generated transgenic mice to express human RPE65 in the cones of mice where RPE65 expression is normally restricted to the pigmented epithelium. Comparison of control (RPE65-deficient) and transgenic (RPE65-expressing) cones revealed no morphological or functional changes, with only a slight delay in dark adaptation, possibly caused by the buffering of retinoids by RPE65. Together, our results do not provide any evidence for a functional role of RPE65 in mouse cones. Future studies will have to determine whether cone-expressed RPE65 plays a role in maintaining the long-term homeostasis of retinoids in cones and their function and survival, particularly in humans.
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155
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Palczewska G, Stremplewski P, Suh S, Alexander N, Salom D, Dong Z, Ruminski D, Choi EH, Sears AE, Kern TS, Wojtkowski M, Palczewski K. Two-photon imaging of the mammalian retina with ultrafast pulsing laser. JCI Insight 2018; 3:121555. [PMID: 30185665 DOI: 10.1172/jci.insight.121555] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 07/24/2018] [Indexed: 12/13/2022] Open
Abstract
Noninvasive imaging of visual system components in vivo is critical for understanding the causal mechanisms of retinal diseases and for developing therapies for their treatment. However, ultraviolet light needed to excite endogenous fluorophores that participate in metabolic processes of the retina is highly attenuated by the anterior segment of the human eye. In contrast, 2-photon excitation fluorescence imaging with pulsed infrared light overcomes this obstacle. Reducing retinal exposure to laser radiation remains a major barrier in advancing this technology to studies in humans. To increase fluorescence intensity and reduce the requisite laser power, we modulated ultrashort laser pulses with high-order dispersion compensation and applied sensorless adaptive optics and custom image recovery software and observed an over 300% increase in fluorescence of endogenous retinal fluorophores when laser pulses were shortened from 75 fs to 20 fs. No functional or structural changes to the retina were detected after exposure to 2-photon excitation imaging light with 20-fs pulses. Moreover, wide bandwidth associated with short pulses enables excitation of multiple fluorophores with different absorption spectra and thus can provide information about their relative changes and intracellular distribution. These data constitute a substantial advancement for safe 2-photon fluorescence imaging of the human eye.
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Affiliation(s)
| | - Patrycjusz Stremplewski
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Susie Suh
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Nathan Alexander
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - David Salom
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Zhiqian Dong
- Polgenix, Inc., Department of Medical Devices, Cleveland, Ohio, USA
| | - Daniel Ruminski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Elliot H Choi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Avery E Sears
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Timothy S Kern
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Maciej Wojtkowski
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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156
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Gao S, Parmar T, Palczewska G, Dong Z, Golczak M, Palczewski K, Jastrzebska B. Protective Effect of a Locked Retinal Chromophore Analog against Light-Induced Retinal Degeneration. Mol Pharmacol 2018; 94:1132-1144. [PMID: 30018116 DOI: 10.1124/mol.118.112581] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 07/11/2018] [Indexed: 01/10/2023] Open
Abstract
Continuous regeneration of the 11-cis-retinal visual chromophore from all-trans-retinal is critical for vision. Insufficiency of 11-cis-retinal arising from the dysfunction of key proteins involved in its regeneration can impair retinal health, ultimately leading to loss of human sight. Delayed recovery of visual sensitivity and night blindness caused by inadequate regeneration of the visual pigment rhodopsin are typical early signs of this condition. Excessive concentrations of unliganded, constitutively active opsin and increased levels of all-trans-retinal and its byproducts in photoreceptors also accelerate retinal degeneration after light exposure. Exogenous 9-cis-retinal iso-chromophore can reduce the toxicity of ligand-free opsin but fails to prevent the buildup of retinoid photoproducts when their clearance is defective in human retinopathies, such as Stargardt disease or age-related macular degeneration. Here we evaluated the effect of a locked chromophore analog, 11-cis-6-membered ring-retinal against bright light-induced retinal degeneration in Abca4-/-Rdh8-/- mice. Using in vivo imaging techniques, optical coherence tomography, scanning laser ophthalmoscopy, and two-photon microscopy, along with in vitro histologic analysis of retinal morphology, we found that treatment with 11-cis-6-membered ring-retinal before light stimulation prevented rod and cone photoreceptor degradation and preserved functional acuity in these mice. Moreover, additive accumulation of 11-cis-6-membered ring-retinal measured in the eyes of these mice by quantitative liquid chromatography-mass spectrometry indicated stable binding of this retinoid to opsin. Together, these results suggest that eliminating excess of unliganded opsin can prevent light-induced retinal degeneration in Abca4-/-Rdh8-/- mice.
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Affiliation(s)
- Songqi Gao
- Department of Pharmacology, School of Medicine (S.G., T.P., M.G., K.P., B.J.) and Cleveland Center for Membrane and Structural Biology (M.G., K.P., B.J.), Case Western Reserve University, and Polgenix Inc., Department of Medical Devices (G.P., Z.D.), Cleveland, Ohio
| | - Tanu Parmar
- Department of Pharmacology, School of Medicine (S.G., T.P., M.G., K.P., B.J.) and Cleveland Center for Membrane and Structural Biology (M.G., K.P., B.J.), Case Western Reserve University, and Polgenix Inc., Department of Medical Devices (G.P., Z.D.), Cleveland, Ohio
| | - Grazyna Palczewska
- Department of Pharmacology, School of Medicine (S.G., T.P., M.G., K.P., B.J.) and Cleveland Center for Membrane and Structural Biology (M.G., K.P., B.J.), Case Western Reserve University, and Polgenix Inc., Department of Medical Devices (G.P., Z.D.), Cleveland, Ohio
| | - Zhiqian Dong
- Department of Pharmacology, School of Medicine (S.G., T.P., M.G., K.P., B.J.) and Cleveland Center for Membrane and Structural Biology (M.G., K.P., B.J.), Case Western Reserve University, and Polgenix Inc., Department of Medical Devices (G.P., Z.D.), Cleveland, Ohio
| | - Marcin Golczak
- Department of Pharmacology, School of Medicine (S.G., T.P., M.G., K.P., B.J.) and Cleveland Center for Membrane and Structural Biology (M.G., K.P., B.J.), Case Western Reserve University, and Polgenix Inc., Department of Medical Devices (G.P., Z.D.), Cleveland, Ohio
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine (S.G., T.P., M.G., K.P., B.J.) and Cleveland Center for Membrane and Structural Biology (M.G., K.P., B.J.), Case Western Reserve University, and Polgenix Inc., Department of Medical Devices (G.P., Z.D.), Cleveland, Ohio
| | - Beata Jastrzebska
- Department of Pharmacology, School of Medicine (S.G., T.P., M.G., K.P., B.J.) and Cleveland Center for Membrane and Structural Biology (M.G., K.P., B.J.), Case Western Reserve University, and Polgenix Inc., Department of Medical Devices (G.P., Z.D.), Cleveland, Ohio
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157
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Tochitsky I, Kienzler MA, Isacoff E, Kramer RH. Restoring Vision to the Blind with Chemical Photoswitches. Chem Rev 2018; 118:10748-10773. [PMID: 29874052 DOI: 10.1021/acs.chemrev.7b00723] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Degenerative retinal diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) affect millions of people around the world and lead to irreversible vision loss if left untreated. A number of therapeutic strategies have been developed over the years to treat these diseases or restore vision to already blind patients. In this Review, we describe the development and translational application of light-sensitive chemical photoswitches to restore visual function to the blind retina and compare the translational potential of photoswitches with other vision-restoring therapies. This therapeutic strategy is enabled by an efficient fusion of chemical synthesis, chemical biology, and molecular biology and is broadly applicable to other biological systems. We hope this Review will be of interest to chemists as well as neuroscientists and clinicians.
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Affiliation(s)
- Ivan Tochitsky
- F.M. Kirby Neurobiology Center , Boston Children's Hospital , Boston , Massachusetts 02115 , United States.,Department of Neurobiology , Harvard Medical School , Boston , Massachusetts 02115 , United States
| | - Michael A Kienzler
- Department of Chemistry , University of Maine , Orono , Maine 04469 , United States
| | - Ehud Isacoff
- Department of Molecular and Cell Biology , University of California , Berkeley , California 94720 , United States.,Helen Wills Neuroscience Institute , University of California , Berkeley , California 94720 , United States.,Bioscience Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Richard H Kramer
- Department of Molecular and Cell Biology , University of California , Berkeley , California 94720 , United States.,Helen Wills Neuroscience Institute , University of California , Berkeley , California 94720 , United States
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158
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Rifaie-Graham O, Ulrich S, Galensowske NFB, Balog S, Chami M, Rentsch D, Hemmer JR, Read de Alaniz J, Boesel LF, Bruns N. Wavelength-Selective Light-Responsive DASA-Functionalized Polymersome Nanoreactors. J Am Chem Soc 2018; 140:8027-8036. [DOI: 10.1021/jacs.8b04511] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Omar Rifaie-Graham
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Sebastian Ulrich
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
- Laboratory for Biomimetic Membranes and Textiles, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | | | - Sandor Balog
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Mohamed Chami
- BioEM lab, Center of Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Mattenstrasse 26, 4056 Basel, Switzerland
| | - Daniel Rentsch
- Laboratory for Functional Polymers, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - James R. Hemmer
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Javier Read de Alaniz
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Luciano F. Boesel
- Laboratory for Biomimetic Membranes and Textiles, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Nico Bruns
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
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159
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Abstract
Apocarotenoids are cleavage products of C40 isoprenoid pigments, named carotenoids, synthesized exclusively by plants and microorganisms. The colors of flowers and fruits and the photosynthetic process are examples of the biological properties conferred by carotenoids to these organisms. Mammals do not synthesize carotenoids but obtain them from foods of plant origin. Apocarotenoids are generated upon enzymatic and nonenzymatic cleavage of the parent compounds both in plants and in the tissues of mammals that have ingested carotenoid-containing foods. The best-characterized apocarotenoids are retinoids (vitamin A and its derivatives), generated upon central oxidative cleavage of provitamin A carotenoids, mainly β-carotene. In addition to the well-known biological actions of vitamin A, it is becoming apparent that nonretinoid apocarotenoids also have the potential to regulate a broad spectrum of critical cellular functions, thus influencing mammalian health. This review discusses the current knowledge about the generation and biological activities of nonretinoid apocarotenoids in mammals.
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Affiliation(s)
- Earl H Harrison
- Department of Human Sciences, The Ohio State University, Columbus, Ohio 43210, USA;
| | - Loredana Quadro
- Department of Food Science; Rutgers Center for Lipid Research; and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901, USA;
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160
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Behnen P, Felline A, Comitato A, Di Salvo MT, Raimondi F, Gulati S, Kahremany S, Palczewski K, Marigo V, Fanelli F. A Small Chaperone Improves Folding and Routing of Rhodopsin Mutants Linked to Inherited Blindness. iScience 2018; 4:1-19. [PMID: 30240733 PMCID: PMC6147235 DOI: 10.1016/j.isci.2018.05.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 04/06/2018] [Accepted: 04/30/2018] [Indexed: 11/24/2022] Open
Abstract
The autosomal dominant form of retinitis pigmentosa (adRP) is a blindness-causing conformational disease largely linked to mutations of rhodopsin. Molecular simulations coupled to the graph-based protein structure network (PSN) analysis and in vitro experiments were conducted to determine the effects of 33 adRP rhodopsin mutations on the structure and routing of the opsin protein. The integration of atomic and subcellular levels of analysis was accomplished by the linear correlation between indices of mutational impairment in structure network and in routing. The graph-based index of structural perturbation served also to divide the mutants in four clusters, consistent with their differences in subcellular localization and responses to 9-cis retinal. The stability core of opsin inferred from PSN analysis was targeted by virtual screening of over 300,000 anionic compounds leading to the discovery of a reversible orthosteric inhibitor of retinal binding more effective than retinal in improving routing of three adRP mutants. In silico and in vitro analyses of adRP rhodopsin mutants bridged folding and routing Structure network analysis grouped mutants amenable to treatment with small chaperones Virtual compound screening against the stability core of opsin found a small chaperone The pharmacoperone is a reversible orthosteric inhibitor of retinal binding
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Affiliation(s)
- Petra Behnen
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Angelo Felline
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy
| | - Antonella Comitato
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Maria Teresa Di Salvo
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy
| | - Francesco Raimondi
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy
| | - Sahil Gulati
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 East 101st Street, Cleveland, OH 44106, USA
| | - Shirin Kahremany
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 East 101st Street, Cleveland, OH 44106, USA
| | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy; Center for Neuroscience and Neurotechnology, via Campi 287, 41125 Modena, Italy.
| | - Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy; Center for Neuroscience and Neurotechnology, via Campi 287, 41125 Modena, Italy.
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161
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Segelken J, Wallisch M, Schultz K, Christoffers J, Janssen-Bienhold U. Synthesis and Evaluation of Two Novel All -trans-Retinoic Acid Conjugates: Biocompatible and Functional Tools for Retina Research. ACS Chem Neurosci 2018; 9:858-867. [PMID: 29482329 DOI: 10.1021/acschemneuro.7b00452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The vitamin A derivative all- trans-retinoic acid (ATRA) is an important biologically active metabolite that regulates a variety of essential biological processes in particular via gene-regulatory mechanisms. In the retina, ATRA is a light-dependent byproduct of the phototransduction cascade. Here, ATRA is not only needed for proper retinal development, but it also acts as a neuromodulator on horizontal cells, second-order inhibitory neurons in the outer retina, which reveal morphological and physiological changes when the retina is treated with ATRA. There is evidence that gene-regulatory mechanisms may only be partially involved in these neuromodulatory processes and the underlying nontranscriptional mechanisms are still elusive. This is, among other things, due to the lack of appropriately labeled ATRA, which would allow the tracking of ATRA in cells or a given tissue. To overcome this obstacle, we designed, synthesized, and evaluated two conjugates of ATRA, one conjugated with biotin (biotin-ATRA) and one conjugated with diaminoterephthalate fluorophore (DAT-ATRA), as molecular tools for different fields of application. The biocompatibility of both compounds was demonstrated via cell viability assays in cultured N2a-cells. N2a-cells exposed to the compounds showed no significant changes in the viability rate. The functionality of synthesized ATRA-conjugates was verified using retinal tissue derived from adult carp. The binding of ATRA-conjugates to distinct retinal cells was assessed in primary cultures of carp retina. Hereby, horizontal and Müller cells have been identified as specific target cells of the new ATRA compounds. Electron microscopy further confirmed that the new substances are still able to induce synaptic plasticity at horizontal cell dendrites resulting in formation of spine synapses, as it is shown for native ATRA. Taken together, the novel ATRA-conjugates represent biocompatible and functional molecular tools, which may further provide the possibility to track ATRA in neuronal cells and study its modulatory effects in different cell systems.
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Affiliation(s)
- Jasmin Segelken
- Neurobiology, University of Oldenburg, D-26111 Oldenburg, Germany
- Visual Neuroscience, Department of Neuroscience, University of Oldenburg, D-26111 Oldenburg, Germany
| | - Melanie Wallisch
- Institut für Chemie, Universität Oldenburg, D-26111 Oldenburg, Germany
| | - Konrad Schultz
- Neurobiology, University of Oldenburg, D-26111 Oldenburg, Germany
| | - Jens Christoffers
- Institut für Chemie, Universität Oldenburg, D-26111 Oldenburg, Germany
| | - Ulrike Janssen-Bienhold
- Neurobiology, University of Oldenburg, D-26111 Oldenburg, Germany
- Visual Neuroscience, Department of Neuroscience, University of Oldenburg, D-26111 Oldenburg, Germany
- Research Center Neurosensory Science, University of Oldenburg, D-26111 Oldenburg, Germany
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162
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Shields CW, White JP, Osta EG, Patel J, Rajkumar S, Kirby N, Therrien JP, Zauscher S. Encapsulation and controlled release of retinol from silicone particles for topical delivery. J Control Release 2018; 278:37-48. [PMID: 29604311 DOI: 10.1016/j.jconrel.2018.03.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 03/11/2018] [Accepted: 03/23/2018] [Indexed: 01/07/2023]
Abstract
Retinol, a derivative of vitamin A, is a ubiquitous compound used to treat acne, reduce wrinkles and protect against conditions like psoriasis and ichthyosis. While retinol is used as the primary active ingredient (AI) in many skin care formulations, its efficacy is often limited by an extreme sensitivity to degrade and toxicity at high concentrations. While microencapsulation is an appealing method to help overcome these issues, few microencapsulation strategies have made a major translational impact due to challenges with complexity, cost, limited protection of the AI and poor control of the release of the AI. We have developed a class of silicone particles that addresses these challenges for the encapsulation, protection and controlled release of retinol and other hydrophobic compounds. The particles are prepared by the sol-gel polymerization of silane monomers, which enables their rapid and facile synthesis at scale while maintaining a narrow size distribution (i.e., CV < 20%). We show that our particles can: (i) encapsulate retinol with high efficiency (>85%), (ii) protect retinol from degradation (yielding a half-life 9× greater than unencapsulated retinol) and (iii) slowly release retinol over several hours (at rates from 0.14 to 0.67 μg cm-2 s-1/2). To demonstrate that the controlled release of retinol from the particles can reduce irritation, we performed a double blind study on human subjects and found that formulations containing our particles were 12-23% less irritating than identical formulations containing Microsponge® particles (an industry standard by Amcol, Inc.). To show that the silicone particles can elicit a favorable biological response, similar to the Microsponge® particles, we applied both formulations to reconstructed human epidermal tissues and found an upregulation of keratin 19 (K19) and a downregulation of K10, indicating that the reduced irritation observed in the human study was not caused by reduced activity. We also found a decrease in the production of interleukin-1α (IL-1α) compared to formulations containing the Microsponge particles, suggesting lower irritation levels and supporting the findings from the human study. Finally, we show that the silicone particles can encapsulate other AIs, including betamethasone, N, N-diethyl-meta-toluamide (DEET), homosalate and ingenol mebutate, establishing these particles as a true platform technology.
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Affiliation(s)
- C Wyatt Shields
- NSF Research Triangle Materials Research Science and Engineering Center, Duke University, Durham, NC 27708, USA; Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA.
| | - John P White
- NSF Research Triangle Materials Research Science and Engineering Center, Duke University, Durham, NC 27708, USA; Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Erica G Osta
- NSF Research Triangle Materials Research Science and Engineering Center, Duke University, Durham, NC 27708, USA; NSF Partnerships for Research and Education in Materials, Texas State University, San Marcos, TX 78666, USA
| | - Jerishma Patel
- NSF Research Triangle Materials Research Science and Engineering Center, Duke University, Durham, NC 27708, USA; Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Shashank Rajkumar
- NSF Research Triangle Materials Research Science and Engineering Center, Duke University, Durham, NC 27708, USA; Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Nickolas Kirby
- NSF Research Triangle Materials Research Science and Engineering Center, Duke University, Durham, NC 27708, USA
| | | | - Stefan Zauscher
- NSF Research Triangle Materials Research Science and Engineering Center, Duke University, Durham, NC 27708, USA; Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA; Department of Chemistry, Duke University, Durham, NC 27708, USA.
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163
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BEST1 gene therapy corrects a diffuse retina-wide microdetachment modulated by light exposure. Proc Natl Acad Sci U S A 2018; 115:E2839-E2848. [PMID: 29507198 PMCID: PMC5866594 DOI: 10.1073/pnas.1720662115] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
One of the most common forms of monogenic macular degeneration worldwide is caused by dominant or recessive bestrophinopathies associated with mutations in the BEST1 gene. Disease expression is known to start with a retina-wide electrophysiological defect leading to localized vitelliform and atrophic lesions and vision loss. To develop lasting therapies for this incurable disease, there is a need for greater understanding of the early pathophysiology before lesion formation. Here we find that the loss of retinal pigment epithelium apical microvilli and resulting microdetachment of the retina represent the earliest features of canine bestrophinopathies. We show that retinal light exposure expands, and dark adaptation contracts, the microdetachments. Subretinal adeno-associated virus-based gene therapy corrects both the vitelliform lesions and the light-modulated microdetachments. Mutations in the BEST1 gene cause detachment of the retina and degeneration of photoreceptor (PR) cells due to a primary channelopathy in the neighboring retinal pigment epithelium (RPE) cells. The pathophysiology of the interaction between RPE and PR cells preceding the formation of retinal detachment remains not well-understood. Our studies of molecular pathology in the canine BEST1 disease model revealed retina-wide abnormalities at the RPE-PR interface associated with defects in the RPE microvillar ensheathment and a cone PR-associated insoluble interphotoreceptor matrix. In vivo imaging demonstrated a retina-wide RPE–PR microdetachment, which contracted with dark adaptation and expanded upon exposure to a moderate intensity of light. Subretinal BEST1 gene augmentation therapy using adeno-associated virus 2 reversed not only clinically detectable subretinal lesions but also the diffuse microdetachments. Immunohistochemical analyses showed correction of the structural alterations at the RPE–PR interface in areas with BEST1 transgene expression. Successful treatment effects were demonstrated in three different canine BEST1 genotypes with vector titers in the 0.1-to-5E11 vector genomes per mL range. Patients with biallelic BEST1 mutations exhibited large regions of retinal lamination defects, severe PR sensitivity loss, and slowing of the retinoid cycle. Human translation of canine BEST1 gene therapy success in reversal of macro- and microdetachments through restoration of cytoarchitecture at the RPE–PR interface has promise to result in improved visual function and prevent disease progression in patients affected with bestrophinopathies.
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164
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Kiser PD, Zhang J, Sharma A, Angueyra JM, Kolesnikov AV, Badiee M, Tochtrop GP, Kinoshita J, Peachey NS, Li W, Kefalov VJ, Palczewski K. Retinoid isomerase inhibitors impair but do not block mammalian cone photoreceptor function. J Gen Physiol 2018; 150:571-590. [PMID: 29500274 PMCID: PMC5881442 DOI: 10.1085/jgp.201711815] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 12/18/2017] [Accepted: 01/22/2018] [Indexed: 12/11/2022] Open
Abstract
RPE65 is a retinoid isomerase essential for rod function, but its contribution to cone vision is enigmatic. Using selective RPE65 inhibitors, Kiser et al. demonstrate that cone function depends only partially on continuous RPE65 activity, providing support for cone-specific regeneration mechanisms. Visual function in vertebrates critically depends on the continuous regeneration of visual pigments in rod and cone photoreceptors. RPE65 is a well-established retinoid isomerase in the pigment epithelium that regenerates rhodopsin during the rod visual cycle; however, its contribution to the regeneration of cone pigments remains obscure. In this study, we use potent and selective RPE65 inhibitors in rod- and cone-dominant animal models to discern the role of this enzyme in cone-mediated vision. We confirm that retinylamine and emixustat-family compounds selectively inhibit RPE65 over DES1, the putative retinoid isomerase of the intraretinal visual cycle. In vivo and ex vivo electroretinography experiments in Gnat1−/− mice demonstrate that acute administration of RPE65 inhibitors after a bleach suppresses the late, slow phase of cone dark adaptation without affecting the initial rapid portion, which reflects intraretinal visual cycle function. Acute administration of these compounds does not affect the light sensitivity of cone photoreceptors in mice during extended exposure to background light, but does slow all phases of subsequent dark recovery. We also show that cone function is only partially suppressed in cone-dominant ground squirrels and wild-type mice by multiday administration of an RPE65 inhibitor despite profound blockade of RPE65 activity. Complementary experiments in these animal models using the DES1 inhibitor fenretinide show more modest effects on cone recovery. Collectively, these studies demonstrate a role for continuous RPE65 activity in mammalian cone pigment regeneration and provide further evidence for RPE65-independent regeneration mechanisms.
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Affiliation(s)
- Philip D Kiser
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH .,Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH
| | - Jianye Zhang
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH
| | - Aditya Sharma
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, MO
| | - Juan M Angueyra
- Retinal Neurophysiology Section, National Eye Institute, Bethesda, MD
| | - Alexander V Kolesnikov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, MO
| | - Mohsen Badiee
- Department of Chemistry, College of Arts and Sciences, Case Western Reserve University, Cleveland, OH
| | - Gregory P Tochtrop
- Department of Chemistry, College of Arts and Sciences, Case Western Reserve University, Cleveland, OH
| | | | - Neal S Peachey
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH.,Cole Eye Institute, Cleveland Clinic, Cleveland, OH.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH
| | - Wei Li
- Retinal Neurophysiology Section, National Eye Institute, Bethesda, MD
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, MO
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH
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165
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Gao S, Kahremany S, Zhang J, Jastrzebska B, Querubin J, Petersen-Jones SM, Palczewski K. Retinal-chitosan Conjugates Effectively Deliver Active Chromophores to Retinal Photoreceptor Cells in Blind Mice and Dogs. Mol Pharmacol 2018; 93:438-452. [PMID: 29453250 DOI: 10.1124/mol.117.111294] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/13/2018] [Indexed: 12/13/2022] Open
Abstract
The retinoid (visual) cycle consists of a series of biochemical reactions needed to regenerate the visual chromophore 11-cis-retinal and sustain vision. Genetic or environmental factors affecting chromophore production can lead to blindness. Using animal models that mimic human retinal diseases, we previously demonstrated that mechanism-based pharmacological interventions can maintain vision in otherwise incurable genetic diseases of the retina. Here, we report that after 9-cis-retinal administration to lecithin:retinol acyltransferase-deficient (Lrat-/- ) mice, the drug was rapidly absorbed and then cleared within 1 to 2 hours. However, when conjugated to form chitosan-9-cis-retinal, this prodrug was slowly absorbed from the gastrointestinal tract, resulting in sustainable plasma levels of 9-cis-retinol and recovery of visual function without causing elevated levels, as occurs with unconjugated drug treatment. Administration of chitosan-9-cis-retinal conjugate intravitreally in retinal pigment epithelium-specific 65 retinoid isomerase (RPE65)-deficient dogs improved photoreceptor function as assessed by electroretinography. Functional rescue was dose dependent and maintained for several weeks. Dosing via the gastrointestinal tract in canines was found ineffective, most likely due to peculiarities of vitamin A blood transport in canines. Use of the chitosan conjugate in combination with 11-cis-6-ring-retinal, a locked ring analog of 11-cis-retinal that selectively blocks rod opsin consumption of chromophore while largely sparing cone opsins, was found to prolong cone vision in Lrat-/- mice. Development of such combination low-dose regimens to selectively prolong useful cone vision could not only expand retinal disease treatments to include Leber congenital amaurosis but also the age-related decline in human dark adaptation from progressive retinoid cycle deficiency.
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Affiliation(s)
- Songqi Gao
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Shirin Kahremany
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Jianye Zhang
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Beata Jastrzebska
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Janice Querubin
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Simon M Petersen-Jones
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
| | - Krzysztof Palczewski
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio (S.G., S.K., J.Z., B.J., K.P.) and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan (J.Q., S.M.P.-J.)
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166
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Amirjalayer S, Martinez‐Cuezva A, Berna J, Woutersen S, Buma WJ. Photoinduced Pedalo-Type Motion in an Azodicarboxamide-Based Molecular Switch. Angew Chem Int Ed Engl 2018; 57:1792-1796. [PMID: 29139183 PMCID: PMC5814897 DOI: 10.1002/anie.201709666] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/23/2017] [Indexed: 01/05/2023]
Abstract
Well-defined structural changes of molecular units that can be triggered by light are crucial for the development of photoactive functional materials. Herein, we report on a novel switch that has azodicarboxamide as its photo-triggerable element. Time-resolved UV-pump/IR probe spectroscopy in combination with quantum-chemical calculations shows that the azodicarboxamide functionality, in contrast to other azo-based chromophores, does not undergo trans-cis photoisomerization. Instead, a photoinduced pedalo-type motion occurs, which because of its volume-conserving properties enables the design of functional molecular systems with controllable motion in a confined space.
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Affiliation(s)
- Saeed Amirjalayer
- Physikalisches Institut and Center for Multiscale Theory and ComputationWestfälische Wilhelms-Universität MünsterWillhelm-Klemm-Strasse 1048149MünsterGermany
- Center for Nanotechnology (CeNTech)Heisenbergstrasse 1148149MünsterGermany
| | | | - Jose Berna
- Departamento de Química OrgánicaFacultad de QuímicaUniversidad de Murcia30100MurciaSpain
| | - Sander Woutersen
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098XHAmsterdamThe Netherlands
| | - Wybren Jan Buma
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098XHAmsterdamThe Netherlands
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167
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Wheway G, Nazlamova L, Hancock JT. Signaling through the Primary Cilium. Front Cell Dev Biol 2018; 6:8. [PMID: 29473038 PMCID: PMC5809511 DOI: 10.3389/fcell.2018.00008] [Citation(s) in RCA: 302] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/23/2018] [Indexed: 12/13/2022] Open
Abstract
The presence of single, non-motile “primary” cilia on the surface of epithelial cells has been well described since the 1960s. However, for decades these organelles were believed to be vestigial, with no remaining function, having lost their motility. It wasn't until 2003, with the discovery that proteins responsible for transport along the primary cilium are essential for hedgehog signaling in mice, that the fundamental importance of primary cilia in signal transduction was realized. Little more than a decade later, it is now clear that the vast majority of signaling pathways in vertebrates function through the primary cilium. This has led to the adoption of the term “the cells's antenna” as a description for the primary cilium. Primary cilia are particularly important during development, playing fundamental roles in embryonic patterning and organogenesis, with a suite of inherited developmental disorders known as the “ciliopathies” resulting from mutations in genes encoding cilia proteins. This review summarizes our current understanding of the role of these fascinating organelles in a wide range of signaling pathways.
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Affiliation(s)
- Gabrielle Wheway
- Department of Applied Science, Faculty of Health and Applied Sciences, Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
| | - Liliya Nazlamova
- Department of Applied Science, Faculty of Health and Applied Sciences, Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
| | - John T Hancock
- Department of Applied Science, Faculty of Health and Applied Sciences, Centre for Research in Biosciences, University of the West of England, Bristol, United Kingdom
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168
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Caprice K, Pupier M, Kruve A, Schalley CA, Cougnon FBL. Imine-based [2]catenanes in water. Chem Sci 2018; 9:1317-1322. [PMID: 29675178 PMCID: PMC5887103 DOI: 10.1039/c7sc04901c] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 12/18/2017] [Indexed: 01/07/2023] Open
Abstract
We report the efficient condensation of imine-based macrocycles from dialdehyde A and aliphatic diamines B n in pure water. Within the libraries, we identified a family of homologous amphiphilic [2]catenanes, whose self-assembly is primarily driven by the hydrophobic effect. The length and odd-even character of the diamine alkyl linker dictate both the yield and the conformation of the [2]catenanes, whose particular thermodynamic stability further shifts the overall equilibrium in favour of imine condensation. These findings highlight the role played by solvophobic effects in the self-assembly of complex architectures.
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Affiliation(s)
- Kenji Caprice
- Department of Organic Chemistry , University of Geneva , 30 Quai Ernest Ansermet , 1211 Geneva 4 , Switzerland .
| | - Marion Pupier
- Department of Organic Chemistry , University of Geneva , 30 Quai Ernest Ansermet , 1211 Geneva 4 , Switzerland .
| | - Anneli Kruve
- Institut für Chemie und Biochemie , Freie Universität Berlin , Takustraße 3 , 14195 Berlin , Germany
| | - Christoph A Schalley
- Institut für Chemie und Biochemie , Freie Universität Berlin , Takustraße 3 , 14195 Berlin , Germany
| | - Fabien B L Cougnon
- Department of Organic Chemistry , University of Geneva , 30 Quai Ernest Ansermet , 1211 Geneva 4 , Switzerland .
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169
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Abstract
Small molecules have extensive untapped potential to benefit society, but access to this potential is too often restricted by limitations inherent to the customized approach currently used to synthesize this class of chemical matter. In contrast, the "building block approach", i.e., generalized iterative assembly of interchangeable parts, has now proven to be a highly efficient and flexible way to construct things ranging all the way from skyscrapers to macromolecules to artificial intelligence algorithms. The structural redundancy found in many small molecules suggests that they possess a similar capacity for generalized building block-based construction. It is also encouraging that many customized iterative synthesis methods have been developed that improve access to specific classes of small molecules. There has also been substantial recent progress toward the iterative assembly of many different types of small molecules, including complex natural products, pharmaceuticals, biological probes, and materials, using common building blocks and coupling chemistry. Collectively, these advances suggest that a generalized building block approach for small molecule synthesis may be within reach.
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Affiliation(s)
- Jonathan W Lehmann
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Daniel J Blair
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Martin D Burke
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA and Carle-Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA
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170
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Parmar VM, Parmar T, Arai E, Perusek L, Maeda A. A2E-associated cell death and inflammation in retinal pigmented epithelial cells from human induced pluripotent stem cells. Stem Cell Res 2018; 27:95-104. [PMID: 29358124 PMCID: PMC5877810 DOI: 10.1016/j.scr.2018.01.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 12/28/2017] [Accepted: 01/10/2018] [Indexed: 01/12/2023] Open
Abstract
Accumulation of lipofuscin in the retinal pigmented epithelium (RPE) is observed in retinal degenerative diseases including Stargardt disease and age-related macular degeneration. Bis-retinoid N-retinyl-N-retinylidene ethanolamine (A2E) is a major component of lipofuscin. A2E has been implicated in RPE atrophy and retinal inflammation; however, mice with A2E accumulation display only a mild retinal phenotype. In the current study, human iPSC-RPE (hiPSC-RPE) cells were generated from healthy individuals to examine effects of A2E in human RPE cells. hiPSC-RPE cells displayed RPE-specific features, which include expression of RPE-specific genes, tight junction formation and ability to carry out phagocytosis. hiPSC-RPE cells demonstrated cell death and increased VEGF-A production in a time-dependent manner when they were cocultured with 10 μM of A2E. PCR array analyses revealed upregulation of 26 and 12 pro-inflammatory cytokines upon A2E and H2O2 exposure respectively, indicating that A2E and H2O2 can cause inflammation in human retinas. Notably, identified gene profiles were different between A2E- and H2O2-treated hiPSC-RPE cells. A2E caused inflammatory changes observed in retinal degenerative diseases more closely as compared to H2O2. Collectively, these data obtained with hiPSC-RPE cells provide evidence that A2E plays an important role in pathogenesis of retinal degenerative diseases in humans.
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Affiliation(s)
- Vipul M Parmar
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, United States
| | - Tanu Parmar
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, United States
| | - Eisuke Arai
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, United States
| | - Lindsay Perusek
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, United States
| | - Akiko Maeda
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, United States; Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, United States.
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171
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Ingenbleek Y. The Retinol Circulating Complex Releases Hormonal Ligands During Acute Stress Disorders. Front Endocrinol (Lausanne) 2018; 9:487. [PMID: 30233492 PMCID: PMC6131608 DOI: 10.3389/fendo.2018.00487] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 08/06/2018] [Indexed: 12/18/2022] Open
Abstract
Intensive care workers actively participate in very hot debates aiming at defining the true metabolic, hormonal and nutritional requirements of critically ill patients, the contributory roles played by thyroid and retinoid ligands being largely underestimated. The present article makes up for redressing the balance on behalf of these last hormonal compounds. The retinol circulating complex is transported in the bloodstream in the form of a trimolecular edifice made up of transthyretin (TTR), retinol-binding protein (RBP) and its retinol ligand. TTR reflects the size of the lean body mass (LBM) and is one of the 3 carrier-proteins of thyroid hormones whereas RBP is the sole conveyor of retinol in human plasma. In acute inflammatory disorders, both TTR and RBP analytes experience abrupt cytokine-induced suppressed hepatic synthesis whose amplitude is dependent on the duration and severity of the inflammatory burden. The steep drop in TTR and RBP plasma values releases thyroxine and retinol ligands in their physiologically active forms, creating free pools estimated to be 10-20 times larger than those described in healthy subjects. The peak endocrine influence is reached on day 4 and the freed ligands undergo instant cellular overconsumption and urinary leakage of unmetabolized fractions. As a result of these transient hyperthyroid and hyperretinoid states, helpful stimulatory and/or inhibitory processes are set in motion, operating as second frontlines fine-tuning the impulses primarily initiated by cytokines. The data explain why preexisting protein malnutrition, as assessed by subnormal LBM and TTR values, impairs the development of appropriate recovery processes in critically ill patients. These findings have survival implications, emphasizing the need for more adapted therapeutic strategies in intensive care units.
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172
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Tanaka K, R. Pradipta A, Latypova L, Chulakova D, Smirnov I, Kurbangalieva A. Cycloaddition Reactions of N-Alkyl-α,β-unsaturated Imines: Facile Preparation of Azaheterocycles for Synthesis and Biological Applications. HETEROCYCLES 2018. [DOI: 10.3987/rev-18-sr(t)4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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173
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Scholl HPN, Strauss RW, Singh MS, Dalkara D, Roska B, Picaud S, Sahel JA. Emerging therapies for inherited retinal degeneration. Sci Transl Med 2017; 8:368rv6. [PMID: 27928030 DOI: 10.1126/scitranslmed.aaf2838] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 11/17/2016] [Indexed: 12/13/2022]
Abstract
Inherited retinal degenerative diseases, a genetically and phenotypically heterogeneous group of disorders, affect the function of photoreceptor cells and are among the leading causes of blindness. Recent advances in molecular genetics and cell biology are elucidating the pathophysiological mechanisms underlying these disorders and are helping to identify new therapeutic approaches, such as gene therapy, stem cell therapy, and optogenetics. Several of these approaches have entered the clinical phase of development. Artificial replacement of dying photoreceptor cells using retinal prostheses has received regulatory approval. Precise retinal imaging and testing of visual function are facilitating more efficient clinical trial design. In individual patients, disease stage will determine whether the therapeutic strategy should comprise photoreceptor cell rescue to delay or arrest vision loss or retinal replacement for vision restoration.
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Affiliation(s)
- Hendrik P N Scholl
- Department of Ophthalmology, University of Basel, 4056 Basel, Switzerland. .,Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Rupert W Strauss
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA.,Moorfields Eye Hospital, London EC1V 2PD, U.K.,UCL Institute of Ophthalmology, University College London, London EC1V 9EL, U.K.,Department of Ophthalmology, Medical University Graz, Graz, Austria.,Department of Ophthalmology, Johannes Kepler University Linz, 4021 Linz, Austria
| | - Mandeep S Singh
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Deniz Dalkara
- INSERM, UMR S 968, 75012 Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Institut de la Vision, Paris, France.,CNRS, UMR 7210, 75012 Paris, France
| | - Botond Roska
- Department of Ophthalmology, University of Basel, 4056 Basel, Switzerland.,Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Serge Picaud
- INSERM, UMR S 968, 75012 Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Institut de la Vision, Paris, France.,CNRS, UMR 7210, 75012 Paris, France
| | - José-Alain Sahel
- INSERM, UMR S 968, 75012 Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Institut de la Vision, Paris, France.,CNRS, UMR 7210, 75012 Paris, France.,Fondation Ophtalmologique Adolphe de Rothschild, 75019 Paris, France.,Centre d'Investigation Clinique 1423, INSERM-Center Hospitalier National d'Ophtalmologie des Quinze-Vingts, 75012 Paris, France.,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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174
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Rajapakse D, Peterson K, Mishra S, Wistow G. Serum starvation of ARPE-19 changes the cellular distribution of cholesterol and Fibulin3 in patterns reminiscent of age-related macular degeneration. Exp Cell Res 2017; 361:333-341. [PMID: 29097185 PMCID: PMC5701823 DOI: 10.1016/j.yexcr.2017.10.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/25/2017] [Accepted: 10/28/2017] [Indexed: 11/29/2022]
Abstract
Retinal pigment epithelium (RPE) has been implicated as key source of cholesterol-rich deposits at Bruch's membrane (BrM) and in drusen in aging human eye. We have shown that serum-deprivation of confluent RPE cells is associated with upregulation of cholesterol synthesis and accumulation of unesterified cholesterol (UC). Here we investigate the cellular processes involved in this response. We compared the distribution and localization of UC and esterified cholesterol (EC); the age-related macular degeneration (AMD) associated EFEMP1/Fibulin3 (Fib3); and levels of acyl-coenzyme A (CoA): cholesterol acyltransferases (ACAT) ACAT1, ACAT2 and Apolipoprotein B (ApoB) in ARPE-19 cells cultured in serum-supplemented and serum-free media. The results were compared with distributions of these lipids and proteins in human donor eyes with AMD. Serum deprivation of ARPE-19 was associated with increased formation of FM dye-positive membrane vesicles, many of which co-labeled for UC. Additionally, UC colocalized with Fib3 in distinct granules. By day 5, serum-deprived cells grown on transwells secreted Fib3 basally into the matrix. While mRNA and protein levels of ACTA1 were constant over several days of serum-deprivation, ACAT2 levels increased significantly after serum-deprivation, suggesting increased formation of EC. The lower levels of intracellular EC observed under serum-deprivation were associated with increased formation and secretion of ApoB. The responses to serum-deprivation in RPE-derived cells: accumulation and secretion of lipids, lipoproteins, and Fib3 are very similar to patterns seen in human donor eyes with AMD and suggest that this model mimics processes relevant to disease progression.
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Affiliation(s)
- Dinusha Rajapakse
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Building 6 Room 106, Bethesda, MD, USA.
| | - Katherine Peterson
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Building 6 Room 106, Bethesda, MD, USA.
| | - Sanghamitra Mishra
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Building 6 Room 106, Bethesda, MD, USA.
| | - Graeme Wistow
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Building 6 Room 106, Bethesda, MD, USA.
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175
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Amirjalayer S, Martinez-Cuezva A, Berna J, Woutersen S, Buma WJ. Photoinduced Pedalo-Type Motion in an Azodicarboxamide-Based Molecular Switch. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201709666] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Saeed Amirjalayer
- Physikalisches Institut and Center for Multiscale Theory and Computation; Westfälische Wilhelms-Universität Münster; Willhelm-Klemm-Strasse 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech); Heisenbergstrasse 11 48149 Münster Germany
| | - Alberto Martinez-Cuezva
- Departamento de Química Orgánica; Facultad de Química; Universidad de Murcia; 30100 Murcia Spain
| | - Jose Berna
- Departamento de Química Orgánica; Facultad de Química; Universidad de Murcia; 30100 Murcia Spain
| | - Sander Woutersen
- Van't Hoff Institute for Molecular Sciences; University of Amsterdam; Science Park 904 1098 XH Amsterdam The Netherlands
| | - Wybren Jan Buma
- Van't Hoff Institute for Molecular Sciences; University of Amsterdam; Science Park 904 1098 XH Amsterdam The Netherlands
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176
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Melanopsin mRNA in the Iris of Red-Eared Slider Turtles (Trachemys scripta elegans). J HERPETOL 2017. [DOI: 10.1670/16-046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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177
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Dephosphorylation by protein phosphatase 2A regulates visual pigment regeneration and the dark adaptation of mammalian photoreceptors. Proc Natl Acad Sci U S A 2017; 114:E9675-E9684. [PMID: 29078372 DOI: 10.1073/pnas.1712405114] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Resetting of G-protein-coupled receptors (GPCRs) from their active state back to their biologically inert ground state is an integral part of GPCR signaling. This "on-off" GPCR cycle is regulated by reversible phosphorylation. Retinal rod and cone photoreceptors arguably represent the best-understood example of such GPCR signaling. Their visual pigments (opsins) are activated by light, transduce the signal, and are then inactivated by a GPCR kinase and arrestin. Although pigment inactivation by phosphorylation is well understood, the enzyme(s) responsible for pigment dephosphorylation and the functional significance of this reaction remain unknown. Here, we show that protein phosphatase 2A (PP2A) acts as opsin phosphatase in both rods and cones. Elimination of PP2A substantially slows pigment dephosphorylation, visual chromophore recycling, and ultimately photoreceptor dark adaptation. These findings demonstrate that visual pigment dephosphorylation regulates the dark adaptation of photoreceptors and provide insights into the role of this reaction in GPCR signaling.
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178
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Malechka VV, Moiseyev G, Takahashi Y, Shin Y, Ma JX. Impaired Rhodopsin Generation in the Rat Model of Diabetic Retinopathy. THE AMERICAN JOURNAL OF PATHOLOGY 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] [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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179
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Sears AE, Bernstein PS, Cideciyan AV, Hoyng C, Charbel Issa P, Palczewski K, Rosenfeld PJ, Sadda S, Schraermeyer U, Sparrow JR, Washington I, Scholl HPN. Towards Treatment of Stargardt Disease: Workshop Organized and Sponsored by the Foundation Fighting Blindness. Transl Vis Sci Technol 2017; 6:6. [PMID: 28920007 PMCID: PMC5599228 DOI: 10.1167/tvst.6.5.6] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 07/11/2017] [Indexed: 01/13/2023] Open
Abstract
Accumulation of fluorescent metabolic byproducts of the visual (retinoid) cycle is associated with photoreceptor and retinal pigment epithelial cell death in both Stargardt disease and atrophic (nonneovascular) age-related macular degeneration (AMD). As a consequence of this observation, small molecular inhibitors of enzymes in the visual cycle were recently tested in clinical trials as a strategy to protect the retina and retinal pigment epithelium in patients with atrophic AMD. To address the clinical translational needs for therapies aimed at both diseases, a workshop organized by the Foundation Fighting Blindness was hosted by the Department of Pharmacology at Case Western Reserve University on February 17, 2017, at the Tinkham Veale University Center, Cleveland, OH, USA. Invited speakers highlighted recent advances in the understanding of the pathophysiology of Stargardt disease, in terms of its clinical characterization and the development of endpoints for clinical trials, and discussed the comparability of therapeutic strategies between atrophic age-related macular degeneration (AMD) and Stargardt disease. Investigators speculated that reducing the concentrations of visual cycle precursor substances and/or their byproducts may provide valid therapeutic options for the treatment of Stargardt disease. Here we review the workshop's presentations in the context of published literature to help shape the aims of ongoing research endeavors and aid the development of therapies for Stargardt disease.
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Affiliation(s)
- Avery E Sears
- Department of Pharmacology, School of Medicine, Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH, USA
| | | | - Artur V Cideciyan
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Carel Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Peter Charbel Issa
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, and the Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH, USA
| | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - SriniVas Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, USA
| | - Ulrich Schraermeyer
- Institute of Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Janet R Sparrow
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA
| | - Ilyas Washington
- Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA
| | - Hendrik P N Scholl
- Department of Ophthalmology, University of Basel, Basel, Switzerland.,Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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180
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Chelstowska S, Widjaja-Adhi MAK, Silvaroli JA, Golczak M. Impact of LCA-Associated E14L LRAT Mutation on Protein Stability and Retinoid Homeostasis. Biochemistry 2017; 56:4489-4499. [PMID: 28758396 PMCID: PMC5682948 DOI: 10.1021/acs.biochem.7b00451] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vitamin A (all-trans-retinol) is metabolized to the visual chromophore (11-cis-retinal) in the eyes and to all-trans-retinoic acid, a hormone like compound, in most tissues. A key enzyme in retinoid metabolism is lecithin:retinol acyltransferase (LRAT), which catalyzes the esterification of vitamin A. The importance of LRAT is indicated by pathogenic missense and nonsense mutations, which cause devastating blinding diseases. Retinoid-based chromophore replacement therapy has been proposed as treatment for these types of blindness based on studies in LRAT null mice. Here, we analyzed the structural and biochemical basis for retinal pathology caused by mutations in the human LRAT gene. Most LRAT missense mutations associated with retinal degeneration are localized within the catalytic domain, whereas E14L substitution is localized in an N-terminal α-helix, which has been implicated in interaction with the phospholipid bilayer. To elucidate the biochemical consequences of this mutation, we determined LRAT(E14L)'s enzymatic properties, protein stability, and impact on ocular retinoid metabolism. Bicistronic expression of LRAT(E14L) and enhanced green fluorescence protein revealed instability and accelerated proteosomal degradation of this mutant isoform. Surprisingly, instability of LRAT(E14L) did not abrogate the production of the visual chromophore in a cell-based assay. Instead, expression of LRAT(E14L) led to a rapid increase in cellular levels of retinoic acid upon retinoid supplementation. Thus, our study unveils the potential role of retinoic acid in the pathology of a degenerative retinal disease with important implications for the use of retinoid-based therapeutics in affected patients.
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Affiliation(s)
- Sylwia Chelstowska
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, United States
- Laboratory of Hematology and Flow Cytometry, Department of Hematology, Military Institute of Medicine, Warsaw 04141, Poland
| | | | - Josie A. Silvaroli
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Marcin Golczak
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, United States
- Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, United States
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181
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Du M, Phelps E, Balangue MJ, Dockins A, Moiseyev G, Shin Y, Kane S, Otalora L, Ma JX, Farjo R, Farjo KM. Transgenic Mice Over-Expressing RBP4 Have RBP4-Dependent and Light-Independent Retinal Degeneration. Invest Ophthalmol Vis Sci 2017; 58:4375–4383. [PMID: 28813718 PMCID: PMC5560100 DOI: 10.1167/iovs.17-22107] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Purpose Transgenic mice overexpressing serum retinol-binding protein (RBP4-Tg) develop progressive retinal degeneration, characterized by microglia activation, yet the precise mechanisms underlying retinal degeneration are unclear. Previous studies showed RBP4-Tg mice have normal ocular retinoid levels, suggesting that degeneration is independent of the retinoid visual cycle or light exposure. The present study addresses whether retinal degeneration is light-dependent and RBP4-dependent by testing the effects of dark-rearing and pharmacological lowering of serum RBP4 levels, respectively. Methods RBP4-Tg mice reared on normal mouse chow in normal cyclic light conditions were directly compared to RBP4-Tg mice exposed to chow supplemented with the RBP4-lowering compound A1120 or dark-rearing conditions. Quantitative retinal histological analysis was conducted to assess retinal degeneration, and electroretinography (ERG) and optokinetic tracking (OKT) tests were performed to assess retinal and visual function. Ocular retinoids and bis-retinoid A2E were quantified. Results Dark-rearing RBP4-Tg mice effectively reduced ocular bis-retinoid A2E levels, but had no significant effect on retinal degeneration or dysfunction in RBP4-Tg mice, demonstrating that retinal degeneration is light-independent. A1120 treatment lowered serum RBP4 levels similar to wild-type mice, and prevented structural retinal degeneration. However, A1120 treatment did not prevent retinal dysfunction in RBP4-Tg mice. Moreover, RBP4-Tg mice on A1120 diet had significant worsening of OKT response and loss of cone photoreceptors compared to RBP4-Tg mice on normal chow. This may be related to the very significant reduction in retinyl ester levels in the retina of mice on A1120-supplemented diet. Conclusions Retinal degeneration in RBP4-Tg mice is RBP4-dependent and light-independent.
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Affiliation(s)
- Mei Du
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Eric Phelps
- EyeCRO LLC, Oklahoma City, Oklahoma, United States
| | | | | | - Gennadiy Moiseyev
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Younghwa Shin
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Shelley Kane
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Laura Otalora
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Jian-Xing Ma
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Rafal Farjo
- EyeCRO LLC, Oklahoma City, Oklahoma, United States
| | - Krysten M Farjo
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
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182
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Sharma R, Schwarz C, Hunter JJ, Palczewska G, Palczewski K, Williams DR. Formation and Clearance of All-Trans-Retinol in Rods Investigated in the Living Primate Eye With Two-Photon Ophthalmoscopy. Invest Ophthalmol Vis Sci 2017; 58:604-613. [PMID: 28129424 PMCID: PMC5283085 DOI: 10.1167/iovs.16-20061] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Two-photon excited fluorescence (TPEF) imaging has potential as a functional tool for tracking visual pigment regeneration in the living eye. Previous studies have shown that all-trans-retinol is likely the chief source of time-varying TPEF from photoreceptors. Endogenous TPEF from retinol could provide the specificity desired for tracking the visual cycle. However, in vivo characterization of native retinol kinetics is complicated by visual stimulation from the imaging beam. We have developed an imaging scheme for overcoming these challenges and monitored the formation and clearance of retinol. Methods Three macaques were imaged by using an in vivo two-photon ophthalmoscope. Endogenous TPEF was excited at 730 nm and recorded through the eye's pupil for more than 90 seconds. Two-photon excited fluorescence increased with onset of light and plateaued within 40 seconds, at which point, brief incremental stimuli were delivered at 561 nm. The responses of rods to stimulation were analyzed by using first-order kinetics. Results Two-photon excited fluorescence resulting from retinol production corresponded to the fraction of rhodopsin bleached. The photosensitivity of rhodopsin was estimated to be 6.88 ± 5.50 log scotopic troland. The rate of retinol clearance depended on intensity of incremental stimulation. Clearance was faster for stronger stimuli and time constants ranged from 50 to 300 seconds. Conclusions This study demonstrates a method for rapidly measuring the rate of clearance of retinol in vivo. Moreover, TPEF generated due to retinol can be used as a measure of rhodopsin depletion, similar to densitometry. This enhances the utility of two-photon ophthalmoscopy as a technique for evaluating the visual cycle in the living eye.
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Affiliation(s)
- Robin Sharma
- Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Christina Schwarz
- Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Jennifer J Hunter
- Center for Visual Science, University of Rochester, Rochester, New York, United States 2Flaum Eye Institute, University of Rochester, Rochester, New York, United States 3Biomedical Engineering, University of Rochester, Rochester, New York, United States
| | | | - Krzysztof Palczewski
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - David R Williams
- Center for Visual Science, University of Rochester, Rochester, New York, United States 2Flaum Eye Institute, University of Rochester, Rochester, New York, United States 6The Institute of Optics, University of Rochester, Rochester, New York, United States
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183
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Kiser PD, Zhang J, Badiee M, Kinoshita J, Peachey NS, Tochtrop GP, Palczewski K. Rational Tuning of Visual Cycle Modulator Pharmacodynamics. J Pharmacol Exp Ther 2017; 362:131-145. [PMID: 28476927 DOI: 10.1124/jpet.117.240721] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 05/01/2017] [Indexed: 11/22/2022] Open
Abstract
Modulators of the visual cycle have been developed for treatment of various retinal disorders. These agents were designed to inhibit retinoid isomerase [retinal pigment epithelium-specific 65 kDa protein (RPE65)], the rate-limiting enzyme of the visual cycle, based on the idea that attenuation of visual pigment regeneration could reduce formation of toxic retinal conjugates. Of these agents, certain ones that contain primary amine groups can also reversibly form retinaldehyde Schiff base adducts, which contributes to their retinal protective activity. Direct inhibition of RPE65 as a therapeutic strategy is complicated by adverse effects resulting from slowed chromophore regeneration, whereas effective retinal sequestration can require high drug doses with potential off-target effects. We hypothesized that the RPE65-emixustat crystal structure could help guide the design of retinaldehyde-sequestering agents with varying degrees of RPE65 inhibitory activity. We found that addition of an isopropyl group to the central phenyl ring of emixustat and related compounds resulted in agents effectively lacking in vitro retinoid isomerase inhibitory activity, whereas substitution of the terminal 6-membered ring with branched moieties capable of stronger RPE65 interaction potentiated inhibition. The isopropyl derivative series produced discernible visual cycle suppression in vivo, albeit much less potently than compounds with a high affinity for the RPE65 active site. These agents were distributed into the retina and formed Schiff base adducts with retinaldehyde. Except for one compound [3-amino-1-(3-isopropyl-5-((2,6,6-trimethylcyclohex-1-en-1-yl)methoxy)phenyl)propan-1-ol (MB-007)], these agents conferred protection against retinal phototoxicity, suggesting that both direct RPE65 inhibition and retinal sequestration are mechanisms of potential therapeutic relevance.
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Affiliation(s)
- Philip D Kiser
- Department of Pharmacology, School of Medicine (P.D.K., J.Z., K.P.), Department of Chemistry (M.B., G.P.T.), Case Western Reserve University, Cleveland, Ohio; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio (P.D.K., N.S.P.); Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio (J.K., N.S.P.); and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio (N.S.P.)
| | - Jianye Zhang
- Department of Pharmacology, School of Medicine (P.D.K., J.Z., K.P.), Department of Chemistry (M.B., G.P.T.), Case Western Reserve University, Cleveland, Ohio; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio (P.D.K., N.S.P.); Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio (J.K., N.S.P.); and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio (N.S.P.)
| | - Mohsen Badiee
- Department of Pharmacology, School of Medicine (P.D.K., J.Z., K.P.), Department of Chemistry (M.B., G.P.T.), Case Western Reserve University, Cleveland, Ohio; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio (P.D.K., N.S.P.); Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio (J.K., N.S.P.); and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio (N.S.P.)
| | - Junzo Kinoshita
- Department of Pharmacology, School of Medicine (P.D.K., J.Z., K.P.), Department of Chemistry (M.B., G.P.T.), Case Western Reserve University, Cleveland, Ohio; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio (P.D.K., N.S.P.); Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio (J.K., N.S.P.); and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio (N.S.P.)
| | - Neal S Peachey
- Department of Pharmacology, School of Medicine (P.D.K., J.Z., K.P.), Department of Chemistry (M.B., G.P.T.), Case Western Reserve University, Cleveland, Ohio; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio (P.D.K., N.S.P.); Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio (J.K., N.S.P.); and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio (N.S.P.)
| | - Gregory P Tochtrop
- Department of Pharmacology, School of Medicine (P.D.K., J.Z., K.P.), Department of Chemistry (M.B., G.P.T.), Case Western Reserve University, Cleveland, Ohio; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio (P.D.K., N.S.P.); Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio (J.K., N.S.P.); and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio (N.S.P.)
| | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine (P.D.K., J.Z., K.P.), Department of Chemistry (M.B., G.P.T.), Case Western Reserve University, Cleveland, Ohio; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio (P.D.K., N.S.P.); Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio (J.K., N.S.P.); and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio (N.S.P.)
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184
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Golubev A, Hanson AD, Gladyshev VN. Non-enzymatic molecular damage as a prototypic driver of aging. J Biol Chem 2017; 292:6029-6038. [PMID: 28264930 PMCID: PMC5391736 DOI: 10.1074/jbc.r116.751164] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The chemical potentialities of metabolites far exceed metabolic requirements. The required potentialities are realized mostly through enzymatic catalysis. The rest are realized spontaneously through organic reactions that (i) occur wherever appropriate reactants come together, (ii) are so typical that many have proper names (e.g. Michael addition, Amadori rearrangement, and Pictet-Spengler reaction), and (iii) often have damaging consequences. There are many more causes of non-enzymatic damage to metabolites than reactive oxygen species and free radical processes (the "usual suspects"). Endogenous damage accumulation in non-renewable macromolecules and spontaneously polymerized material is sufficient to account for aging and differentiates aging from wear-and-tear of inanimate objects by deriving it from metabolism, the essential attribute of life.
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Affiliation(s)
- Alexey Golubev
- From the Department of Biochemistry, Saint-Petersburg State University, Saint Petersburg 199034, Russia,
| | - Andrew D Hanson
- the Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611, and
| | - Vadim N Gladyshev
- the Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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185
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Zhao Q, Tognetti V, Joubert L, Besset T, Pannecoucke X, Bouillon JP, Poisson T. Palladium-Catalyzed Synthesis of 3-Trifluoromethyl-Substituted 1,3-Butadienes by Means of Directed C-H Bond Functionalization. Org Lett 2017; 19:2106-2109. [PMID: 28378584 DOI: 10.1021/acs.orglett.7b00704] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A palladium-catalyzed C-H bond functionalization of acrylamides was developed to build up stereoselectively trifluoromethylated 1,3-butadienes. Using a tertiary amide as a directing group, olefins were selectively functionalized with 2-bromo-3,3,3-trifluoropropene to access these important fluorinated compounds. The methodology was extended to the construction of pentafluoroethyl-substituted 1,3-dienes. Mechanistic studies supported by density functional theory calculations suggested a redox neutral mechanism for this transformation.
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Affiliation(s)
- Qun Zhao
- Normandie Université, INSA Rouen , UNIROUEN, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Vincent Tognetti
- Normandie Université, INSA Rouen , UNIROUEN, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Laurent Joubert
- Normandie Université, INSA Rouen , UNIROUEN, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Tatiana Besset
- Normandie Université, INSA Rouen , UNIROUEN, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Xavier Pannecoucke
- Normandie Université, INSA Rouen , UNIROUEN, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Jean-Philippe Bouillon
- Normandie Université, INSA Rouen , UNIROUEN, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Thomas Poisson
- Normandie Université, INSA Rouen , UNIROUEN, CNRS, COBRA (UMR 6014), 76000 Rouen, France
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186
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Blaner WS. Acyl-CoA wax alcohol acyltransferase 2: its regulation and actions in support of color vision. J Lipid Res 2017; 58:633-635. [PMID: 28232616 PMCID: PMC5392733 DOI: 10.1194/jlr.c075838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Affiliation(s)
- William S Blaner
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032.
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187
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Abstract
Membrane proteins play a most important part in metabolism, signaling, cell motility, transport, development, and many other biochemical and biophysical processes which constitute fundamentals of life on the molecular level. Detailed understanding of these processes is necessary for the progress of life sciences and biomedical applications. Nanodiscs provide a new and powerful tool for a broad spectrum of biochemical and biophysical studies of membrane proteins and are commonly acknowledged as an optimal membrane mimetic system that provides control over size, composition, and specific functional modifications on the nanometer scale. In this review we attempted to combine a comprehensive list of various applications of nanodisc technology with systematic analysis of the most attractive features of this system and advantages provided by nanodiscs for structural and mechanistic studies of membrane proteins.
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Affiliation(s)
- Ilia G Denisov
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
| | - Stephen G Sligar
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
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188
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Photocyclic behavior of rhodopsin induced by an atypical isomerization mechanism. Proc Natl Acad Sci U S A 2017; 114:E2608-E2615. [PMID: 28289214 DOI: 10.1073/pnas.1617446114] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Vertebrate rhodopsin (Rh) contains 11-cis-retinal as a chromophore to convert light energy into visual signals. On absorption of light, 11-cis-retinal is isomerized to all-trans-retinal, constituting a one-way reaction that activates transducin (Gt) followed by chromophore release. Here we report that bovine Rh, regenerated instead with a six-carbon-ring retinal chromophore featuring a C11=C12 double bond locked in its cis conformation (Rh6mr), employs an atypical isomerization mechanism by converting 11-cis to an 11,13-dicis configuration for prolonged Gt activation. Time-dependent UV-vis spectroscopy, HPLC, and molecular mechanics analyses revealed an atypical thermal reisomerization of the 11,13-dicis to the 11-cis configuration on a slow timescale, which enables Rh6mr to function in a photocyclic manner similar to that of microbial Rhs. With this photocyclic behavior, Rh6mr repeatedly recruits and activates Gt in response to light stimuli, making it an excellent candidate for optogenetic tools based on retinal analog-bound vertebrate Rhs. Overall, these comprehensive structure-function studies unveil a unique photocyclic mechanism of Rh activation by an 11-cis-to-11,13-dicis isomerization.
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189
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Shannon SR, Moise AR, Trainor PA. New insights and changing paradigms in the regulation of vitamin A metabolism in development. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 6. [PMID: 28207193 DOI: 10.1002/wdev.264] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/14/2016] [Accepted: 11/24/2016] [Indexed: 12/17/2022]
Abstract
Vitamin A and its active metabolite retinoic acid are essential for embryonic development and adult homeostasis. Surprisingly, excess or deficiency of vitamin A and retinoic acid can cause similar developmental defects. Therefore, strict feedback and other mechanisms exist to regulate the levels of retinoic acid within a narrow physiological range. The oxidation of vitamin A to retinal has recently been established as a critical nodal point in the synthesis of retinoic acid, and over the past decade, RDH10 and DHRS3 have emerged as the predominant enzymes that regulate this reversible reaction. Together they form a codependent complex that facilitates negative feedback maintenance of retinoic acid levels and thus guard against the effects of dysregulated vitamin A metabolism and retinoic acid synthesis. This review focuses on advances in our understanding of the roles of Rdh10 and Dhrs3 and their impact on development and disease. WIREs Dev Biol 2017, 6:e264. doi: 10.1002/wdev.264 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Stephen R Shannon
- Stowers Institute for Medical Research, Kansas City, MO, USA.,Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Alexander R Moise
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, USA
| | - Paul A Trainor
- Stowers Institute for Medical Research, Kansas City, MO, USA.,Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
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190
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Verolet Q, Dal Molin M, Colom A, Roux A, Guénée L, Sakai N, Matile S. Twisted Push-Pull Probes with Turn-On Sulfide Donors. Helv Chim Acta 2017. [DOI: 10.1002/hlca.201600328] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Quentin Verolet
- School of Chemistry and Biochemistry; National Centre of Competence in Research (NCCR) Chemical Biology; University of Geneva; Quai Ernest Ansermet 30 CH-1211 Geneva 4, Switzerland
| | - Marta Dal Molin
- School of Chemistry and Biochemistry; National Centre of Competence in Research (NCCR) Chemical Biology; University of Geneva; Quai Ernest Ansermet 30 CH-1211 Geneva 4, Switzerland
| | - Adai Colom
- School of Chemistry and Biochemistry; National Centre of Competence in Research (NCCR) Chemical Biology; University of Geneva; Quai Ernest Ansermet 30 CH-1211 Geneva 4, Switzerland
| | - Aurélien Roux
- School of Chemistry and Biochemistry; National Centre of Competence in Research (NCCR) Chemical Biology; University of Geneva; Quai Ernest Ansermet 30 CH-1211 Geneva 4, Switzerland
| | - Laure Guénée
- School of Chemistry and Biochemistry; National Centre of Competence in Research (NCCR) Chemical Biology; University of Geneva; Quai Ernest Ansermet 30 CH-1211 Geneva 4, Switzerland
| | - Naomi Sakai
- School of Chemistry and Biochemistry; National Centre of Competence in Research (NCCR) Chemical Biology; University of Geneva; Quai Ernest Ansermet 30 CH-1211 Geneva 4, Switzerland
| | - Stefan Matile
- School of Chemistry and Biochemistry; National Centre of Competence in Research (NCCR) Chemical Biology; University of Geneva; Quai Ernest Ansermet 30 CH-1211 Geneva 4, Switzerland
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191
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Arne JM, Widjaja-Adhi MAK, Hughes T, Huynh KW, Silvaroli JA, Chelstowska S, Moiseenkova-Bell VY, Golczak M. Allosteric modulation of the substrate specificity of acyl-CoA wax alcohol acyltransferase 2. J Lipid Res 2017; 58:719-730. [PMID: 28096191 DOI: 10.1194/jlr.m073692] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/06/2017] [Indexed: 01/30/2023] Open
Abstract
The esterification of alcohols with fatty acids is a universal mechanism to form inert storage forms of sterols, di- and triacylglycerols, and retinoids. In ocular tissues, formation of retinyl esters is an essential step in the enzymatic regeneration of the visual chromophore (11-cis-retinal). Acyl-CoA wax alcohol acyltransferase 2 (AWAT2), also known as multifunctional O-acyltransferase (MFAT), is an integral membrane enzyme with a broad substrate specificity that has been shown to preferentially esterify 11-cis-retinol and thus contribute to formation of a readily available pool of cis retinoids in the eye. However, the mechanism by which this promiscuous enzyme can gain substrate specificity is unknown. Here, we provide evidence for an allosteric modulation of the enzymatic activity by 11-cis retinoids. This regulation is independent from cellular retinaldehyde-binding protein (CRALBP), the major cis-retinoid binding protein. This positive-feedback regulation leads to decreased esterification rates for 9-cis, 13-cis, or all-trans retinols and thus enables preferential synthesis of 11-cis-retinyl esters. Finally, electron microscopy analyses of the purified enzyme indicate that this allosteric effect does not result from formation of functional oligomers. Altogether, these data provide the experimental basis for understanding regulation of AWAT2 substrate specificity.
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Affiliation(s)
- Jason M Arne
- Department of Pharmacology and School of Medicine, Case Western Reserve University, Cleveland, OH
| | | | - Taylor Hughes
- Department of Pharmacology and School of Medicine, Case Western Reserve University, Cleveland, OH
| | - Kevin W Huynh
- Department of Pharmacology and School of Medicine, Case Western Reserve University, Cleveland, OH
| | - Josie A Silvaroli
- Department of Pharmacology and School of Medicine, Case Western Reserve University, Cleveland, OH
| | - Sylwia Chelstowska
- Department of Pharmacology and School of Medicine, Case Western Reserve University, Cleveland, OH; Laboratory of Hematology and Flow Cytometry, Department of Hematology, Military Institute of Medicine, Warsaw, Poland
| | - Vera Y Moiseenkova-Bell
- Department of Pharmacology and School of Medicine, Case Western Reserve University, Cleveland, OH; Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH; and
| | - Marcin Golczak
- Department of Pharmacology and School of Medicine, Case Western Reserve University, Cleveland, OH; Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH; and.
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192
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Yildirim I, Yildirim T, Kalden D, Festag G, Fritz N, Weber C, Schubert S, Westerhausen M, Schubert US. Retinol initiated poly(lactide)s: stability upon polymerization and nanoparticle preparation. Polym Chem 2017. [DOI: 10.1039/c7py00881c] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of retinol initiated polylactide (PLA) by ring opening polymerization (ROP) of l-lactide via in situ calcium alkoxide formation with all-trans-retinol and Ca[N(SiMe3)2]2(THF)2 is described.
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Affiliation(s)
- Ilknur Yildirim
- Laboratory of Organic and Macromolecular Chemistry (IOMC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
- Jena Center for Soft Matter (JCSM)
| | - Turgay Yildirim
- Laboratory of Organic and Macromolecular Chemistry (IOMC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
- Jena Center for Soft Matter (JCSM)
| | - Diana Kalden
- Institute of Inorganic and Analytical Chemistry (IAAC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
| | - Grit Festag
- Laboratory of Organic and Macromolecular Chemistry (IOMC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
- Jena Center for Soft Matter (JCSM)
| | - Nicole Fritz
- Laboratory of Organic and Macromolecular Chemistry (IOMC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
- Jena Center for Soft Matter (JCSM)
| | - Christine Weber
- Laboratory of Organic and Macromolecular Chemistry (IOMC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
- Jena Center for Soft Matter (JCSM)
| | - Stephanie Schubert
- Jena Center for Soft Matter (JCSM)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
- Institute of Pharmacy
| | - Matthias Westerhausen
- Institute of Inorganic and Analytical Chemistry (IAAC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
| | - Ulrich S. Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
- Jena Center for Soft Matter (JCSM)
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193
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Schwarz C, Sharma R, Fischer WS, Chung M, Palczewska G, Palczewski K, Williams DR, Hunter JJ. Safety assessment in macaques of light exposures for functional two-photon ophthalmoscopy in humans. BIOMEDICAL OPTICS EXPRESS 2016; 7:5148-5169. [PMID: 28018732 PMCID: PMC5175559 DOI: 10.1364/boe.7.005148] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 05/18/2023]
Abstract
Two-photon ophthalmoscopy has potential for in vivo assessment of function of normal and diseased retina. However, light safety of the sub-100 fs laser typically used is a major concern and safety standards are not well established. To test the feasibility of safe in vivo two-photon excitation fluorescence (TPEF) imaging of photoreceptors in humans, we examined the effects of ultrashort pulsed light and the required light levels with a variety of clinical and high resolution imaging methods in macaques. The only measure that revealed a significant effect due to exposure to pulsed light within existing safety standards was infrared autofluorescence (IRAF) intensity. No other structural or functional alterations were detected by other imaging techniques for any of the exposures. Photoreceptors and retinal pigment epithelium appeared normal in adaptive optics images. No effect of repeated exposures on TPEF time course was detected, suggesting that visual cycle function was maintained. If IRAF reduction is hazardous, it is the only hurdle to applying two-photon retinal imaging in humans. To date, no harmful effects of IRAF reduction have been detected.
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Affiliation(s)
- Christina Schwarz
- Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Robin Sharma
- Center for Visual Science, University of Rochester, Rochester, NY, USA
| | | | - Mina Chung
- Center for Visual Science, University of Rochester, Rochester, NY, USA
- Flaum Eye Institute, University of Rochester, Rochester, NY, USA
| | | | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - David R. Williams
- Center for Visual Science, University of Rochester, Rochester, NY, USA
- Flaum Eye Institute, University of Rochester, Rochester, NY, USA
- The Institute of Optics, University of Rochester, Rochester, NY, USA
| | - Jennifer J. Hunter
- Center for Visual Science, University of Rochester, Rochester, NY, USA
- Flaum Eye Institute, University of Rochester, Rochester, NY, USA
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA
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194
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Sahu B, Maeda A. Retinol Dehydrogenases Regulate Vitamin A Metabolism for Visual Function. Nutrients 2016; 8:E746. [PMID: 27879662 PMCID: PMC5133129 DOI: 10.3390/nu8110746] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 11/13/2016] [Accepted: 11/16/2016] [Indexed: 02/07/2023] Open
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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195
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Hofmann L, Tsybovsky Y, Alexander NS, Babino D, Leung NY, Montell C, Banerjee S, von Lintig J, Palczewski K. Structural Insights into the Drosophila melanogaster Retinol Dehydrogenase, a Member of the Short-Chain Dehydrogenase/Reductase Family. Biochemistry 2016; 55:6545-6557. [PMID: 27809489 DOI: 10.1021/acs.biochem.6b00907] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The 11-cis-retinylidene chromophore of visual pigments isomerizes upon interaction with a photon, initiating a downstream cascade of signaling events that ultimately lead to visual perception. 11-cis-Retinylidene is regenerated through enzymatic transformations collectively called the visual cycle. The first and rate-limiting enzymatic reaction within this cycle, i.e., the reduction of all-trans-retinal to all-trans-retinol, is catalyzed by retinol dehydrogenases. Here, we determined the structure of Drosophila melanogaster photoreceptor retinol dehydrogenase (PDH) isoform C that belongs to the short-chain dehydrogenase/reductase (SDR) family. This is the first reported structure of a SDR that possesses this biologically important activity. Two crystal structures of the same enzyme grown under different conditions revealed a novel conformational change of the NAD+ cofactor, likely representing a change during catalysis. Amide hydrogen-deuterium exchange of PDH demonstrated changes in the structure of the enzyme upon dinucleotide binding. In D. melanogaster, loss of PDH activity leads to photoreceptor degeneration that can be partially rescued by transgenic expression of human RDH12. Based on the structure of PDH, we analyzed mutations causing Leber congenital amaurosis 13 in a homology model of human RDH12 to obtain insights into the molecular basis of RDH12 disease-causing mutations.
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Affiliation(s)
- Lukas Hofmann
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Yaroslav Tsybovsky
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Nathan S Alexander
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Darwin Babino
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Nicole Y Leung
- Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara , Santa Barbara, California 93106, United States
| | - Craig Montell
- Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara , Santa Barbara, California 93106, United States
| | - Surajit Banerjee
- Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14850, United States.,Northeastern Collaborative Access Team, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Johannes von Lintig
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Krzysztof Palczewski
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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196
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Palczewska G, Maeda A, Golczak M, Arai E, Dong Z, Perusek L, Kevany B, Palczewski K. Receptor MER Tyrosine Kinase Proto-oncogene (MERTK) Is Not Required for Transfer of Bis-retinoids to the Retinal Pigmented Epithelium. J Biol Chem 2016; 291:26937-26949. [PMID: 27875314 DOI: 10.1074/jbc.m116.764563] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 11/14/2016] [Indexed: 01/08/2023] Open
Abstract
Accumulation of bis-retinoids in the retinal pigmented epithelium (RPE) is a hallmark of aging and retinal disorders such as Stargardt disease and age-related macular degeneration. These aberrant fluorescent condensation products, including di-retinoid-pyridinium-ethanolamine (A2E), are thought to be transferred to RPE cells primarily through phagocytosis of the photoreceptor outer segments. However, we observed by two-photon microscopy that mouse retinas incapable of phagocytosis due to a deficiency of the c-Mer proto-oncogene tyrosine kinase (Mertk) nonetheless contained fluorescent retinoid condensation material in their RPE. Primary RPE cells from Mertk-/- mice also accumulated fluorescent products in vitro Finally, quantification of A2E demonstrated the acquisition of retinal condensation products in Mertk-/- mouse RPE prior to retinal degeneration. In these mice, we identified activated microglial cells that likely were recruited to transport A2E-like condensation products to the RPE and dispose of the dying photoreceptor cells. These observations demonstrate a novel transport mechanism between photoreceptor cells and RPE that does not involve canonical Mertk-dependent phagocytosis.
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Affiliation(s)
| | - Akiko Maeda
- the Departments of Ophthalmology and Visual Sciences and
| | - Marcin Golczak
- Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Eisuke Arai
- the Departments of Ophthalmology and Visual Sciences and
| | | | | | - Brian Kevany
- Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Krzysztof Palczewski
- Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
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197
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Molecular Basis for Vitamin A Uptake and Storage in Vertebrates. Nutrients 2016; 8:nu8110676. [PMID: 27792183 PMCID: PMC5133064 DOI: 10.3390/nu8110676] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 09/30/2016] [Accepted: 10/18/2016] [Indexed: 01/27/2023] Open
Abstract
The ability to store and distribute vitamin A inside the body is the main evolutionary adaptation that allows vertebrates to maintain retinoid functions during nutritional deficiencies and to acquire new metabolic pathways enabling light-independent production of 11-cis retinoids. These processes greatly depend on enzymes that esterify vitamin A as well as associated retinoid binding proteins. Although the significance of retinyl esters for vitamin A homeostasis is well established, until recently, the molecular basis for the retinol esterification enzymatic activity was unknown. In this review, we will look at retinoid absorption through the prism of current biochemical and structural studies on vitamin A esterifying enzymes. We describe molecular adaptations that enable retinoid storage and delineate mechanisms in which mutations found in selective proteins might influence vitamin A homeostasis in affected patients.
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198
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Abstract
Retinal photoreceptor cells contain a specialized outer segment (OS) compartment that functions in the capture of light and its conversion into electrical signals in a process known as phototransduction. In rods, photoisomerization of 11-cis to all-trans retinal within rhodopsin triggers a biochemical cascade culminating in the closure of cGMP-gated channels and hyperpolarization of the cell. Biochemical reactions return the cell to its 'dark state' and the visual cycle converts all-trans retinal back to 11-cis retinal for rhodopsin regeneration. OS are continuously renewed, with aged membrane removed at the distal end by phagocytosis and new membrane added at the proximal end through OS disk morphogenesis linked to protein trafficking. The molecular basis for disk morphogenesis remains to be defined in detail although several models have been proposed, and molecular mechanisms underlying protein trafficking are under active investigation. The aim of this Cell Science at a Glance article and the accompanying poster is to highlight our current understanding of photoreceptor structure, phototransduction, the visual cycle, OS renewal, protein trafficking and retinal degenerative diseases.
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Affiliation(s)
- Robert S Molday
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3 Department of Ophthalmology and Visual Sciences, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, Canada V5Z 3N9
| | - Orson L Moritz
- Department of Ophthalmology and Visual Sciences, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, Canada V5Z 3N9
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199
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Tanumihardjo SA, Russell RM, Stephensen CB, Gannon BM, Craft NE, Haskell MJ, Lietz G, Schulze K, Raiten DJ. Biomarkers of Nutrition for Development (BOND)-Vitamin A Review. J Nutr 2016; 146:1816S-48S. [PMID: 27511929 PMCID: PMC4997277 DOI: 10.3945/jn.115.229708] [Citation(s) in RCA: 284] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 04/01/2016] [Accepted: 06/29/2016] [Indexed: 12/15/2022] Open
Abstract
The Biomarkers of Nutrition for Development (BOND) project is designed to provide evidence-informed advice to anyone with an interest in the role of nutrition in health. The BOND program provides information with regard to selection, use, and interpretation of biomarkers of nutrient exposure, status, function, and effect, which will be especially useful for readers who want to assess nutrient status. To accomplish this objective, expert panels are recruited to evaluate the literature and to draft comprehensive reports on the current state of the art with regard to specific nutrient biology and available biomarkers for assessing nutritional status at the individual and population levels. Phase I of the BOND project includes the evaluation of biomarkers for 6 nutrients: iodine, folate, zinc, iron, vitamin A, and vitamin B-12. This review of vitamin A is the current article in this series. Although the vitamin was discovered >100 y ago, vitamin A status assessment is not trivial. Serum retinol concentrations are under homeostatic control due in part to vitamin A's use in the body for growth and cellular differentiation and because of its toxic properties at high concentrations. Furthermore, serum retinol concentrations are depressed during infection and inflammation because retinol-binding protein (RBP) is a negative acute-phase reactant, which makes status assessment challenging. Thus, this review describes the clinical and functional indicators related to eye health and biochemical biomarkers of vitamin A status (i.e., serum retinol, RBP, breast-milk retinol, dose-response tests, isotope dilution methodology, and serum retinyl esters). These biomarkers are then related to liver vitamin A concentrations, which are usually considered the gold standard for vitamin A status. With regard to biomarkers, future research questions and gaps in our current understanding as well as limitations of the methods are described.
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Affiliation(s)
- Sherry A Tanumihardjo
- Interdepartmental Graduate Program in Nutritional Sciences, Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI
| | | | | | - Bryan M Gannon
- Interdepartmental Graduate Program in Nutritional Sciences, Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI
| | | | | | - Georg Lietz
- Newcastle University, Newcastle, United Kingdom
| | - Kerry Schulze
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD; and
| | - Daniel J Raiten
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD
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200
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Nafar Z, Jiang M, Wen R, Jiao S. Visible-light optical coherence tomography-based multimodal retinal imaging for improvement of fluorescent intensity quantification. BIOMEDICAL OPTICS EXPRESS 2016; 7:3220-3229. [PMID: 27699094 PMCID: PMC5030006 DOI: 10.1364/boe.7.003220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/31/2016] [Accepted: 07/31/2016] [Indexed: 05/03/2023]
Abstract
We developed a spectral-domain visible-light optical coherence tomography (VIS-OCT) based multimodal imaging technique which can accomplish simultaneous OCT and fluorescence imaging with a single broadband light source. Phantom experiments showed that by using the simultaneously acquired OCT images as a reference, the effect of light attenuation on the intensity of the fluorescent images by materials in front of the fluorescent target can be compensated. This capability of the multimodal imaging technique is of high importance for achieving quantification of the true intensities of autofluorescence (AF) imaging of the retina. We applied the technique in retinal imaging including AF imaging of the retinal pigment epithelium and fluorescein angiography (FA). We successfully demonstrated the effect of compensation on AF and FA images with the simultaneously acquired VIS-OCT images.
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Affiliation(s)
- Zahra Nafar
- Department of Biomedical Engineering, Florida International University, 10555 W Flagler ST, EC-2610, Miami, FL 33174, USA
| | - Minshan Jiang
- Department of Biomedical Engineering, Florida International University, 10555 W Flagler ST, EC-2610, Miami, FL 33174, USA
| | - Rong Wen
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10 Ave, Miami, FL 33136, USA
| | - Shuliang Jiao
- Department of Biomedical Engineering, Florida International University, 10555 W Flagler ST, EC-2610, Miami, FL 33174, USA
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