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Markitantova Y, Simirskii V. Endogenous and Exogenous Regulation of Redox Homeostasis in Retinal Pigment Epithelium Cells: An Updated Antioxidant Perspective. Int J Mol Sci 2023; 24:10776. [PMID: 37445953 DOI: 10.3390/ijms241310776] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023] Open
Abstract
The retinal pigment epithelium (RPE) performs a range of necessary functions within the neural layers of the retina and helps ensure vision. The regulation of pro-oxidative and antioxidant processes is the basis for maintaining RPE homeostasis and preventing retinal degenerative processes. Long-term stable changes in the redox balance under the influence of endogenous or exogenous factors can lead to oxidative stress (OS) and the development of a number of retinal pathologies associated with RPE dysfunction, and can eventually lead to vision loss. Reparative autophagy, ubiquitin-proteasome utilization, the repair of damaged proteins, and the maintenance of their conformational structure are important interrelated mechanisms of the endogenous defense system that protects against oxidative damage. Antioxidant protection of RPE cells is realized as a result of the activity of specific transcription factors, a large group of enzymes, chaperone proteins, etc., which form many signaling pathways in the RPE and the retina. Here, we discuss the role of the key components of the antioxidant defense system (ADS) in the cellular response of the RPE against OS. Understanding the role and interactions of OS mediators and the components of the ADS contributes to the formation of ideas about the subtle mechanisms in the regulation of RPE cellular functions and prospects for experimental approaches to restore RPE functions.
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Affiliation(s)
- Yuliya Markitantova
- Koltsov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Vladimir Simirskii
- Koltsov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia
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2
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Kitao M, Yamaguchi A, Tomioka T, Kai K, Kamei Y, Sugimoto K, Akagawa M. Astaxanthin protects human ARPE-19 retinal pigment epithelium cells from blue light-induced phototoxicity by scavenging singlet oxygen. Free Radic Res 2023; 57:430-443. [PMID: 37897411 DOI: 10.1080/10715762.2023.2277144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 10/19/2023] [Indexed: 10/30/2023]
Abstract
Age-related macular degeneration (AMD) is one of an increasing number of diseases that causes irreversible impairment and loss of vision in the elderly. AMD occurs by oxidative stress-mediated apoptosis of retinal pigment epithelium cells. The onset of AMD may be positively correlated with the exposure to blue light. We screened food-derived carotenoids for cytoprotective action against blue light irradiation using human ARPE-19 retinal pigment epithelium cells. This study revealed that blue light irradiation triggered apoptosis and oxidative stress in all-trans-retinal (atRAL)-exposed ARPE-19 cells by generating singlet oxygen (1O2), leading to significant cell death. We found that astaxanthin, a potent anti-oxidative xanthophyll abundant in several marine organisms including microalgae, salmon, and shrimp, significantly suppresses blue light-induced apoptotic cell death of atRAL-exposed ARPE-19 cells by scavenging 1O2. Mechanistic studies using the blue-light irradiated cells also demonstrated that the cytoprotective effects of astaxanthin can be attributed to scavenging of 1O2 directly. Our results suggest the potential value of astaxanthin as a dietary strategy to prevent blue light-induced retinal degeneration including AMD.
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Affiliation(s)
- Mana Kitao
- Faculty of Biomolecular Chemistry, Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Ai Yamaguchi
- Faculty of Integrated Bioscience, Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Takuma Tomioka
- Faculty of Biomolecular Chemistry, Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Kenji Kai
- Faculty of Biomolecular Chemistry, Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Yuki Kamei
- Department of Food and Nutrition, Institute of Biomedical sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Kenji Sugimoto
- Faculty of Integrated Bioscience, Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Mitsugu Akagawa
- Department of Food and Nutrition, Institute of Biomedical sciences, Tokushima University Graduate School, Tokushima, Japan
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3
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Chen C, Chen J, Wang Y, Liu Z, Wu Y. Ferroptosis drives photoreceptor degeneration in mice with defects in all-trans-retinal clearance. J Biol Chem 2020; 296:100187. [PMID: 33334878 PMCID: PMC7948481 DOI: 10.1074/jbc.ra120.015779] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/30/2020] [Accepted: 12/14/2020] [Indexed: 12/21/2022] Open
Abstract
The death of photoreceptor cells in dry age-related macular degeneration (AMD) and autosomal recessive Stargardt disease (STGD1) is closely associated with disruption in all-trans-retinal (atRAL) clearance in neural retina. In this study, we reveal that the overload of atRAL leads to photoreceptor degeneration through activating ferroptosis, a nonapoptotic form of cell death. Ferroptosis of photoreceptor cells induced by atRAL resulted from increased ferrous ion (Fe2+), elevated ACSL4 expression, system Xc- inhibition, and mitochondrial destruction. Fe2+ overload, tripeptide glutathione (GSH) depletion, and damaged mitochondria in photoreceptor cells exposed to atRAL provoked reactive oxygen species (ROS) production, which, together with ACSL4 activation, promoted lipid peroxidation and thereby evoked ferroptotic cell death. Moreover, exposure of photoreceptor cells to atRAL activated COX2, a well-accepted biomarker for ferroptosis onset. In addition to GSH supplement, inhibiting either Fe2+ by deferoxamine mesylate salt (DFO) or lipid peroxidation with ferrostatin-1 (Fer-1) protected photoreceptor cells from ferroptosis caused by atRAL. Abca4-/-Rdh8-/- mice exhibiting defects in atRAL clearance is an animal model for dry AMD and STGD1. We observed that ferroptosis was indeed present in neural retina of Abca4-/-Rdh8-/- mice after light exposure. More importantly, photoreceptor atrophy and ferroptosis in light-exposed Abca4-/-Rdh8-/- mice were effectively alleviated by intraperitoneally injected Fer-1, a selective inhibitor of ferroptosis. Our study suggests that ferroptosis is one of the important pathways of photoreceptor cell death in retinopathies arising from excess atRAL accumulation and should be pursued as a novel target for protection against dry AMD and STGD1.
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Affiliation(s)
- Chao Chen
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen City, Fujian, China
| | - Jingmeng Chen
- School of Medicine, Xiamen University, Xiamen City, Fujian, China
| | - Yan Wang
- Department of Ophthalmology, Shenzhen Hospital, Southern Medical University, Shenzhen City, Guangdong, China
| | - Zuguo Liu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen City, Fujian, China
| | - Yalin Wu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen City, Fujian, China; Xiamen Eye Center of Xiamen University, Xiamen City, Fujian, China; Shenzhen Research Institute of Xiamen University, Shenzhen City, Guangdong, China.
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4
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Chen C, Kono M, Koutalos Y. Photooxidation mediated by 11- cis and all- trans retinal in single isolated mouse rod photoreceptors. Photochem Photobiol Sci 2020; 19:1300-1307. [PMID: 32812970 DOI: 10.1039/d0pp00060d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Retinal, the vitamin A aldehyde, is a potent photosensitizer that plays a major role in light-induced damage to vertebrate photoreceptors. 11-Cis retinal is the light-sensitive chromophore of rhodopsin, the photopigment of vertebrate rod photoreceptors. It is isomerized by light to all-trans, activating rhodopsin and beginning the process of light detection. All-trans retinal is released by activated rhodopsin, allowing its regeneration by fresh 11-cis retinal continually supplied to photoreceptors. The released all-trans retinal is reduced to all-trans retinol in a reaction using NADPH. We have examined the photooxidation mediated by 11-cis and all-trans retinal in single living rod photoreceptors isolated from mouse retinas. Photooxidation was measured with fluorescence imaging from the oxidation of internalized BODIPY C11, a fluorescent dye whose fluorescence changes upon oxidation. We found that photooxidation increased with the concentration of exogenously added 11-cis or all-trans retinal to metabolically compromised rod outer segments that lacked NADPH supply. In dark-adapted metabolically intact rod outer segments with access to NADPH, there was no significant increase in photooxidation following exposure of the cell to light, but there was significant increase following addition of exogenous 11-cis retinal. The results indicate that both 11-cis and all-trans retinal can mediate light-induced damage in rod photoreceptors. In metabolically intact cells, the removal of the all-trans retinal generated by light through its reduction to retinol minimizes all-trans retinal-mediated photooxidation. However, because the enzymatic machinery of the rod outer segment cannot remove 11-cis retinal, 11-cis-retinal-mediated photooxidation may play a significant role in light-induced damage to photoreceptor cells.
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Affiliation(s)
- Chunhe Chen
- Department of Ophthalmology, Medical University of South Carolina, 167 Ashley Avenue, Charleston, SC 29425, USA.
| | - Masahiro Kono
- Department of Ophthalmology, Medical University of South Carolina, 167 Ashley Avenue, Charleston, SC 29425, USA.
| | - Yiannis Koutalos
- Department of Ophthalmology, Medical University of South Carolina, 167 Ashley Avenue, Charleston, SC 29425, USA.
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5
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Wu J, Gao ZY, Cui DM, Li HH, Zeng JW. All-trans retinoic acid increases ARPE-19 cell apoptosis via activation of reactive oxygen species and endoplasmic reticulum stress pathways. Int J Ophthalmol 2020; 13:1345-1350. [PMID: 32953569 DOI: 10.18240/ijo.2020.09.01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/02/2020] [Indexed: 02/06/2023] Open
Abstract
AIM To explore the apoptosis of ARPE-19 cells after the treatment with different doses of all-trans-retinoic acid (ATRA). METHODS ARPE-19 cells were used in the in-vitro experiment. Flow cytometry assay was employed to evaluate the level of reactive oxygen species (ROS) and apoptosis. The effects of ATRA (concentrations from 2.5 to 20 µmol/L) on the expression of endoplasmic reticulum stress (ERS) markers in vitro were evaluated by Western blot and real-time quantitative polymerase chain reaction (qRT-PCR) assays. The contribution of ROS and ERS-induced apoptosis in vitro was determined by using N-acetyl-L-cysteine (NAC) and Salubrinal, an antagonist of NAC and ERS, respectively. RESULTS Flow cytometry showed that ATRA significantly increased ARPE-19 cell apoptosis and ROS levels in each group (F=86.39, P<0.001; F=116.839, P<0.001). Western blot and qRT-PCR revealed that levels of CHOP and BIP were elevated in a concentration-dependent pattern after the cells were incubated with ATRA (2.5-20 µmol/L). The upregulation of VEGF-A and CHOP induced by ATRA could be inhibited by NAC (antioxidant) and Salubrinal (ERS inhibitor) in vitro. CONCLUSION ATRA induces the apoptosis of ARPE-19 cells via activated ROS and ERS signaling pathways.
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Affiliation(s)
- Juan Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Zhen-Ya Gao
- Xuchang University, School of Medicine, Xuchang 461000, Henan Province, China
| | - Dong-Mei Cui
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Hong-Hui Li
- Chengdu Aier Eye Hospital, Chengdu 610000, Sichuan Province, China
| | - Jun-Wen Zeng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
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6
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Markitantova YV, Simirskii VN. Role of the Redox System in Initiation of a Regenerative Response of Neural Eye Tissues in Vertebrates. Russ J Dev Biol 2020. [DOI: 10.1134/s106236042001004x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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7
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Cubizolle A, Cia D, Moine E, Jacquemot N, Guillou L, Rosell M, Angebault-Prouteau C, Lenaers G, Meunier I, Vercauteren J, Durand T, Crauste C, Brabet P. Isopropyl-phloroglucinol-DHA protects outer retinal cells against lethal dose of all-trans-retinal. J Cell Mol Med 2020; 24:5057-5069. [PMID: 32212312 PMCID: PMC7205824 DOI: 10.1111/jcmm.15135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/19/2019] [Accepted: 01/27/2020] [Indexed: 12/18/2022] Open
Abstract
All‐trans‐retinal (atRAL) is a highly reactive carbonyl specie, known for its reactivity on cellular phosphatidylethanolamine in photoreceptor. It is generated by photoisomerization of 11‐cis‐retinal chromophore linked to opsin by the Schiff's base reaction. In ABCA4‐associated autosomal recessive Stargardt macular dystrophy, atRAL results in carbonyl and oxidative stress, which leads to bisretinoid A2E, accumulation in the retinal pigment epithelium (RPE). This A2E‐accumulation presents as lipofuscin fluorescent pigment, and its photooxidation causes subsequent damage. Here we describe protection against a lethal dose of atRAL in both photoreceptors and RPE in primary cultures by a lipidic polyphenol derivative, an isopropyl‐phloroglucinol linked to DHA, referred to as IP‐DHA. Next, we addressed the cellular and molecular defence mechanisms in commonly used human ARPE‐19 cells. We determined that both polyunsaturated fatty acid and isopropyl substituents bond to phloroglucinol are essential to confer the highest protection. IP‐DHA responds rapidly against the toxicity of atRAL and its protective effect persists. This healthy effect of IP‐DHA applies to the mitochondrial respiration. IP‐DHA also rescues RPE cells subjected to the toxic effects of A2E after blue light exposure. Together, our findings suggest that the beneficial role of IP‐DHA in retinal cells involves both anti‐carbonyl and anti‐oxidative capacities.
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Affiliation(s)
- Aurélie Cubizolle
- INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, France.,Université Montpellier, Montpellier, France
| | - David Cia
- UMR INSERM 1107, Laboratoire de Biophysique Neurosensorielle, Facultés de Médecine et de Pharmacie, Clermont-Ferrand, France
| | - Espérance Moine
- UMR5247-CNRS-UM ENSCM Faculté de Pharmacie, Institut des Biomolecules Max Mousseron (IBMM), Montpellier, France
| | - Nathalie Jacquemot
- UMR INSERM 1107, Laboratoire de Biophysique Neurosensorielle, Facultés de Médecine et de Pharmacie, Clermont-Ferrand, France
| | - Laurent Guillou
- INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, France.,Université Montpellier, Montpellier, France
| | - Mélissa Rosell
- UMR5247-CNRS-UM ENSCM Faculté de Pharmacie, Institut des Biomolecules Max Mousseron (IBMM), Montpellier, France
| | - Claire Angebault-Prouteau
- Université Montpellier, Montpellier, France.,INSERM U1046, UMR CNRS 9214, CHRU de Montpellier, Montpellier, France
| | - Guy Lenaers
- INSERM U1083, CNRS UMR 6015, MitoVasc-MitoLab, Université d'Angers, Angers, France
| | - Isabelle Meunier
- INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, France.,National Reference Centre for Inherited Sensory Disorders, CHU, Montpellier, France
| | - Joseph Vercauteren
- UMR5247-CNRS-UM ENSCM Faculté de Pharmacie, Institut des Biomolecules Max Mousseron (IBMM), Montpellier, France
| | - Thierry Durand
- UMR5247-CNRS-UM ENSCM Faculté de Pharmacie, Institut des Biomolecules Max Mousseron (IBMM), Montpellier, France
| | - Céline Crauste
- UMR5247-CNRS-UM ENSCM Faculté de Pharmacie, Institut des Biomolecules Max Mousseron (IBMM), Montpellier, France
| | - Philippe Brabet
- INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, France.,Université Montpellier, Montpellier, France
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8
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Blue light-triggered photochemistry and cytotoxicity of retinal. Cell Signal 2020; 69:109547. [PMID: 31982549 DOI: 10.1016/j.cellsig.2020.109547] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/14/2020] [Accepted: 01/22/2020] [Indexed: 01/08/2023]
Abstract
The chemical- and photo- toxicity of chromophore retinal on cells have long been debated. Although we recently showed that retinal and blue light exposure interrupt cellular signaling, a comprehensive study examining molecular underpinnings of this perturbation and its consequences to cellular fate is lacking. Here, we report molecular evidence for blue light excited-retinal induced oxidative damage of polyunsaturated lipid anchors in membrane-interacting signaling molecules and DNA damage in cells using live-cell imaging and in vitro experimentation. The incurred molecular damage irreversibly disrupted subcellular localization of these molecules, a crucial criterion for their signaling. We further show retinal accumulation in lipid-bilayers of cell membranes could enhance the lifetime of retinal in cells. Comparative response-signatures suggest that retinal triggers reactions upon photoexcitation similar to photodynamic therapy agents and generate reactive oxygen species in cells. Additionally, data also shows that exposing retinal-containing cells to sunlight induces substantial cytotoxicity. Collectively, our results explain a likely in vivo mechanism and reaction conditions under which bio-available retinal in physiological light conditions damages cells.
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Terao R, Honjo M, Ueta T, Obinata H, Izumi T, Kurano M, Yatomi Y, Koso H, Watanabe S, Aihara M. Light Stress-Induced Increase of Sphingosine 1-Phosphate in Photoreceptors and Its Relevance to Retinal Degeneration. Int J Mol Sci 2019; 20:ijms20153670. [PMID: 31357484 PMCID: PMC6696268 DOI: 10.3390/ijms20153670] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 07/24/2019] [Indexed: 12/22/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) is a potent lipid mediator that modulates inflammation and angiogenesis. In this study, we investigated the possible involvement of S1P in the pathology of light-induced retinal degeneration in vivo and in vitro. The intracellular S1P and sphingosine kinase (SphK) activity in a photoreceptor cell line (661W cells) was significantly increased by exposure to light. The enhancement of SphK1 expression was dependent on illumination, and all-trans-retinal significantly promoted SphK1 expression. S1P treatment reduced protein kinase B (Akt) phosphorylation and increased the protein expression of cleaved caspase-3, and induced photoreceptor cell apoptosis. In vivo, light exposure enhanced the expression of SphK1 in the outer segments of photoreceptors. Intravitreal injection of a SphK inhibitor significantly suppressed the thinning of the outer nuclear layer and ameliorated the attenuation of the amplitudes of a-waves and b-waves of electroretinograms during light-induced retinal degeneration. These findings imply that light exposure induces the synthesis of S1P in photoreceptors by upregulating SphK1, which is facilitated by all-trans-retinal, causing retinal degeneration. Inhibition of this enhancement may be a therapeutic target of outer retinal degeneration, including age-related macular degeneration.
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Affiliation(s)
- Ryo Terao
- Department of Ophthalmology, Graduate School of Medicine, Tokyo University, Tokyo 113-8654, Japan
| | - Megumi Honjo
- Department of Ophthalmology, Graduate School of Medicine, Tokyo University, Tokyo 113-8654, Japan
| | - Takashi Ueta
- Department of Ophthalmology, Graduate School of Medicine, Tokyo University, Tokyo 113-8654, Japan
| | - Hideru Obinata
- Gunma University Initiative for Advanced Research (GIAR), 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan
| | - Takashi Izumi
- Department of Biochemistry, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan
| | - Makoto Kurano
- Department of Clinical Laboratory Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Yutaka Yatomi
- Department of Clinical Laboratory Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Hideto Koso
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Makoto Aihara
- Department of Ophthalmology, Graduate School of Medicine, Tokyo University, Tokyo 113-8654, Japan.
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10
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Abstract
Photoreceptor chromophore, 11-cis retinal (11CR) and the photoproduct, all-trans retinal (ATR), are present in the retina at higher concentrations and interact with the visual cells. Non-visual cells in the body are also exposed to retinal that enters the circulation. Although the cornea and the lens of the eye are transparent to the blue light region where retinal can absorb and undergo excitation, the reported phototoxicity in the eye has been assigned to lipophilic non-degradable materials known as lipofuscins, which also includes retinal condensation products. The possibility of blue light excited retinal interacting with cells; intercepting signaling in the presence or absence of light has not been explored. Using live cell imaging and optogenetic signaling control, we uncovered that blue light-excited ATR and 11CR irreversibly change/distort plasma membrane (PM) bound phospholipid; phosphatidylinositol 4,5 bisphosphate (PIP2) and disrupt its function. This distortion in PIP2 was independent of visual or non-visual G-protein coupled receptor activation. The change in PIP2 was followed by an increase in the cytosolic calcium, excessive cell shape change, and cell death. Blue light alone or retinal alone did not perturb PIP2 or elicit cytosolic calcium increase. Our data also suggest that photoexcited retinal-induced PIP2 distortion and subsequent oxidative damage incur in the core of the PM. These findings suggest that retinal exerts light sensitivity to both photoreceptor and non-photoreceptor cells, and intercepts crucial signaling events, altering the cellular fate.
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11
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Widomska J, Subczynski WK. Mechanisms enhancing the protective functions of macular xanthophylls in the retina during oxidative stress. Exp Eye Res 2018; 178:238-246. [PMID: 29908882 DOI: 10.1016/j.exer.2018.06.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/26/2018] [Accepted: 06/13/2018] [Indexed: 01/08/2023]
Abstract
Macular xanthophylls (MXs) are distinguished from other dietary carotenoids by their high membrane solubility and preferential transmembrane orientation. Additionally, these properties enhance the chemical and physical stability of MXs in the eye retina, and maximize their protective activities. The effectiveness of MXs' protection is also enhanced by their selective accumulation in the most vulnerable domains of retinal membranes. The retina is protected by MXs mainly through blue-light filtration, quenching of the excited triplet states of potent photosensitizers, and physical quenching of singlet oxygen. To perform these physical, photo-related actions, the structure of MXs should remain intact. However, the conjugated double-bond structure of MXs makes them highly chemically reactive and susceptible to oxidation. Chemical quenching of singlet oxygen and scavenging of free radicals destroy their intact structure and consume MXs. Consequently, their physical actions, which are critical to the protection of retina, are diminished. Thus, it is timely and important to identify mechanisms whereby the chemical destruction (bleaching) of MXs in retinal membranes can be reduced. It was shown that nitroxide free radicals (spin labels) located in membranes protect MXs against destruction, and their effect is especially pronounced during the light-induced formation of singlet oxygen. That should extend and enhance their positive action in the retina through physical processes. In this review, we will discuss possible applications of this new strategy during ophthalmological procedures, which can cause acute bleaching of MXs and damage the retina through oxidative processes.
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Affiliation(s)
- Justyna Widomska
- Department of Biophysics, Medical University of Lublin, Jaczewskiego 4, Lublin, Poland.
| | - Witold K Subczynski
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
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12
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Li J, Zhang Y, Cai X, Xia Q, Chen J, Liao Y, Liu Z, Wu Y. All-trans-retinal dimer formation alleviates the cytotoxicity of all-trans-retinal in human retinal pigment epithelial cells. Toxicology 2016; 371:41-48. [PMID: 27751755 DOI: 10.1016/j.tox.2016.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/09/2016] [Indexed: 12/20/2022]
Abstract
Effective clearance of all-trans-retinal (atRAL) from retinal pigment epithelial (RPE) cells is important for avoiding its cytotoxicity. However, the metabolism of atRAL in RPE cells is poorly clarified. The present study was designed to analyze metabolic products of atRAL and to compare the cytotoxicity of atRAL versus its derivative all-trans-retinal dimer (atRAL-dimer) in human RPE cells. We found that all-trans-retinol (atROL) and a mixture of atRAL condensation metabolites including atRAL-dimer and A2E were generated after incubating RPE cells with atRAL for 6h, and the amount of atRAL-dimer was significantly higher than that of A2E. In the eyes of Rdh8-/- Abca4-/- mice, a mouse model with defects in retinoid cycle that displays some symbolic characteristics of age-related macular degeneration (AMD), the level of atRAL-dimer was increased compared to wild-type mice, and was even much greater than that of A2E & isomers. The cytotoxicity of atRAL-dimer was reduced compared with its precursor atRAL. The latter could provoke intracellular reactive oxygen species (ROS) overproduction, increase the mRNA expression of several oxidative stress related genes (Nrf2, HO-1, and γ-GCSh), and induce ΔΨm loss in RPE cells. By contrast, the abilities of atRAL-dimer to induce intracellular ROS and oxidative stress were much weaker versus that of concentration-matched atRAL, and atRAL-dimer exhibited no toxic effect on mitochondrial function at higher concentrations. In conclusion, the formation of atRAL-dimer during atRAL metabolic process ameliorates the cytotoxicity of atRAL by reducing oxidative stress.
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Affiliation(s)
- Jie Li
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen, Fujian Province, China; Taizhou First People's Hospital, Taizhou, Zhejiang Province, China
| | - Yanli Zhang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Xianhui Cai
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Qingqing Xia
- Taizhou First People's Hospital, Taizhou, Zhejiang Province, China
| | - Jingmeng Chen
- College of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yi Liao
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Zuguo Liu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen, Fujian Province, China
| | - Yalin Wu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute of Xiamen University, College of Medicine, Xiamen University, Xiamen, Fujian Province, China.
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13
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Adler L, Boyer NP, Chen C, Koutalos Y. Kinetics of rhodopsin's chromophore monitored in a single photoreceptor. Methods Mol Biol 2015; 1271:327-43. [PMID: 25697533 DOI: 10.1007/978-1-4939-2330-4_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Absorption of light isomerizes the retinyl chromophore of the photoreceptor pigment rhodopsin from 11-cis to all-trans, generating the photoactivated rhodopsin form. The photoisomerization of the chromophore however destroys rhodopsin, and its regeneration requires the removal of the all-trans and the supply of fresh 11-cis chromophore. The all-trans chromophore is removed through a series of steps beginning with its release from photoactivated rhodopsin in the form of all-trans-retinal, leaving behind the apoprotein opsin. All-trans-retinal is then reduced to all-trans-retinol, which is transported out of the photoreceptor. Rhodopsin is regenerated from opsin and fresh 11-cis-retinal arriving to the photoreceptor from the retinal pigment epithelium. Both all-trans and 11-cis-retinal can form precursors of lipofuscin, a pigment that accumulates with age in the lysosomal compartment of the retinal pigment epithelium. All-trans-retinal, all-trans-retinol, and lipofuscin precursors all emit significant and distinct fluorescence signals, allowing their monitoring in single photoreceptor cells with fluorescence imaging. Here we describe the procedures for measuring these fluorophores in single mouse rod photoreceptors.
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Affiliation(s)
- Leopold Adler
- Departments of Ophthalmology and Neurosciences, Medical University of South Carolina, 167 Ashley Ave., Charleston, SC, 29425, USA
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14
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Zaki MS, Heller R, Thoenes M, Nürnberg G, Stern-Schneider G, Nürnberg P, Karnati S, Swan D, Fateen E, Nagel-Wolfrum K, Mostafa MI, Thiele H, Wolfrum U, Baumgart-Vogt E, Bolz HJ. PEX6 is Expressed in Photoreceptor Cilia and Mutated in Deafblindness with Enamel Dysplasia and Microcephaly. Hum Mutat 2015; 37:170-4. [PMID: 26593283 DOI: 10.1002/humu.22934] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 11/12/2015] [Indexed: 02/06/2023]
Abstract
Deafblindness is part of several genetic disorders. We investigated a consanguineous Egyptian family with two siblings affected by congenital hearing loss and retinal degeneration, initially diagnosed as Usher syndrome type 1. At teenage, severe enamel dysplasia, developmental delay, and microcephaly became apparent. Genome-wide homozygosity mapping and whole-exome sequencing detected a homozygous missense mutation, c.1238G>T (p.Gly413Val), affecting a highly conserved residue of peroxisomal biogenesis factor 6, PEX6. Biochemical profiling of the siblings revealed abnormal and borderline plasma phytanic acid concentration, and cerebral imaging revealed white matter disease in both. We show that Pex6 localizes to the apical extensions of secretory ameloblasts and differentiated odontoblasts at early stages of dentin synthesis in mice, and to cilia of retinal photoreceptor cells. We propose PEX6, and possibly other peroxisomal genes, as candidate for the rare cooccurrence of deafblindness and enamel dysplasia. Our study for the first time links peroxisome biogenesis disorders to retinal ciliopathies.
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Affiliation(s)
- Maha S Zaki
- Department of Clinical Genetics, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Raoul Heller
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Michaela Thoenes
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Gudrun Nürnberg
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Gabi Stern-Schneider
- Department of Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Srikanth Karnati
- Institute for Anatomy and Cell Biology, Justus Liebig University, Giessen, Germany
| | - Daniel Swan
- Computational Biology Group, Oxford Gene Technology, Oxford, United Kingdom
| | - Ekram Fateen
- Department of Biochemical Genetics, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Kerstin Nagel-Wolfrum
- Department of Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Mostafa I Mostafa
- Department of Orodental Genetics, Orodental Research Division, National Research Centre, Cairo, Egypt
| | - Holger Thiele
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Uwe Wolfrum
- Department of Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | | | - Hanno J Bolz
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany.,Bioscientia Center for Human Genetics, Ingelheim, Germany
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Berkowitz BA, Kern TS, Bissig D, Patel P, Bhatia A, Kefalov VJ, Roberts R. Systemic Retinaldehyde Treatment Corrects Retinal Oxidative Stress, Rod Dysfunction, and Impaired Visual Performance in Diabetic Mice. Invest Ophthalmol Vis Sci 2015; 56:6294-303. [PMID: 26431483 PMCID: PMC4594469 DOI: 10.1167/iovs.15-16990] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/04/2015] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Diabetes appears to induce a visual cycle defect because rod dysfunction is correctable with systemic treatment of the visual cycle chromophore 11-cis-retinaldehyde. However, later studies have found no evidence for visual cycle impairment. Here, we further examined whether photoreceptor dysfunction is corrected with 11-cis-retinaldehyde. Because antioxidants correct photoreceptor dysfunction in diabetes, the hypothesis that exogenous visual chromophores have antioxidant activity in the retina of diabetic mice in vivo was tested. METHODS Rod function in 2-month-old diabetic mice was evaluated using transretinal electrophysiology in excised retinas and apparent diffusion coefficient (ADC) MRI to measure light-evoked expansion of subretinal space (SRS) in vivo. Optokinetic tracking was used to evaluate cone-based visual performance. Retinal production of superoxide free radicals, generated mostly in rod cells, was biochemically measured with lucigenin. Diabetic mice were systemically treated with a single injection of either 11-cis-retinaldehyde, 9-cis-retinaldehyde (a chromophore surrogate), or all-trans-retinaldehyde (the photoisomerization product of 11-cis-retinaldehyde). RESULTS Consistent with previous reports, diabetes significantly reduced (1) dark-adapted rod photo responses (transretinal recording) by ∼18%, (2) rod-dominated light-stimulated SRS expansion (ADC MRI) by ∼21%, and (3) cone-dominated contrast sensitivity (using optokinetic tracking [OKT]) by ∼30%. Both 11-cis-retinaldehyde and 9-cis-retinaldehyde largely corrected these metrics of photoreceptor dysfunction. Higher-than-normal retinal superoxide production in diabetes by ∼55% was also significantly corrected following treatment with 11-cis-retinaldehyde, 9-cis-retinaldehyde, or all-trans-retinaldehyde. CONCLUSIONS Collectively, data suggest that retinaldehydes improve photoreceptor dysfunction in diabetic mice, independent of the visual cycle, via an antioxidant mechanism.
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Affiliation(s)
- Bruce A. Berkowitz
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
- Department of Ophthalmology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Timothy S. Kern
- Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States
| | - David Bissig
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Priya Patel
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Ankit Bhatia
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Vladimir J. Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Robin Roberts
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
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Shibagaki K, Okamoto K, Katsuta O, Nakamura M. Beneficial protective effect of pramipexole on light-induced retinal damage in mice. Exp Eye Res 2015. [PMID: 26213307 DOI: 10.1016/j.exer.2015.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We investigated the effects of pramipexole, a potent dopamine receptor D2/D3 agonist, on light-induced retinal damage in mice, H2O2-induced retinal pigment epithelium ARPE-19 cell injury in humans, and hydroxyl radical scavenging activity in a cell-free system. Pramipexole (0.1 and 1 mg/kg body weight) was orally administered to mice 1 h before light exposure (5000 lux, 2 h). Electrophysiological and morphologic studies were performed to evaluate the effects of the pramipexole on light-induced retinal damage in mice. Pramipexole significantly prevented the reduction of the a- and b-wave electroretinogram (ERG) amplitudes caused by light exposure in a dose-dependent manner. In parallel, damage to the inner and outer segments (IS/OS) of the photoreceptors, loss of photoreceptor nuclei, and the number of Tdt-mediated dUTP nick-end labeling (TUNEL)-positive cells in the outer nuclear layer (ONL) caused by light exposure were notably ameliorated by pramipexole. Additionally, pramipexole suppressed H2O2-induced ARPE-19 cell death in vitro in a concentration-dependent manner. The effect of pramipexole was significant at concentrations of 10(-6) M or higher. Pramipexole also significantly prevented H2O2-induced activation of caspases-3/7 and the intracellular accumulation of reactive oxygen species (ROS) in a concentration-dependent manner ranging from 10(-5) to 10(-3) M. Furthermore, pramipexole increased the scavenging activity toward a hydroxyl radical generated from H2O2 in a Fenton reaction. Our results suggest that pramipexole protects against light-induced retinal damage as an antioxidant and that it may be a novel and effective therapy for retinal degenerative disorders, such as dry age-related macular degeneration.
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Affiliation(s)
- Keiichi Shibagaki
- Research and Development Division, Santen Pharmaceutical Co., Ltd., 4-20, Ofuka-cho, Kita-ku, Osaka 530-8552, Japan; Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma-shi, Nara 630-0192, Japan.
| | - Kazuyoshi Okamoto
- Corporate Development Division, Santen Pharmaceutical Co., Ltd., 4-20, Ofuka-cho, Kita-ku, Osaka 530-8552, Japan
| | - Osamu Katsuta
- Research and Development Division, Santen Pharmaceutical Co., Ltd., 4-20, Ofuka-cho, Kita-ku, Osaka 530-8552, Japan
| | - Masatsugu Nakamura
- Research and Development Division, Santen Pharmaceutical Co., Ltd., 4-20, Ofuka-cho, Kita-ku, Osaka 530-8552, Japan
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Li J, Cai X, Xia Q, Yao K, Chen J, Zhang Y, Naranmandura H, Liu X, Wu Y. Involvement of Endoplasmic Reticulum Stress in All-Trans-Retinal-Induced Retinal Pigment Epithelium Degeneration. Toxicol Sci 2014; 143:196-208. [DOI: 10.1093/toxsci/kfu223] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Demmig-Adams B, Adams RB. Eye nutrition in context: mechanisms, implementation, and future directions. Nutrients 2013; 5:2483-501. [PMID: 23857222 PMCID: PMC3738983 DOI: 10.3390/nu5072483] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 06/04/2013] [Accepted: 06/21/2013] [Indexed: 12/12/2022] Open
Abstract
Carotenoid-based visual cues and roles of carotenoids in human vision are reviewed, with an emphasis on protection by zeaxanthin and lutein against vision loss, and dietary sources of zeaxanthin and lutein are summarized. In addition, attention is given to synergistic interactions of zeaxanthin and lutein with other dietary factors affecting human vision (such as antioxidant vitamins, phenolics, and poly-unsaturated fatty acids) and the emerging mechanisms of these interactions. Emphasis is given to lipid oxidation products serving as messengers with functions in gene regulation. Lastly, the photo-physics of light collection and photoprotection in photosynthesis and vision are compared and their common principles identified as possible targets of future research.
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Affiliation(s)
- Barbara Demmig-Adams
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
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Zhong M, Kawaguchi R, Kassai M, Sun H. Retina, retinol, retinal and the natural history of vitamin A as a light sensor. Nutrients 2012; 4:2069-96. [PMID: 23363998 PMCID: PMC3546623 DOI: 10.3390/nu4122069] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 11/27/2012] [Accepted: 11/28/2012] [Indexed: 02/07/2023] Open
Abstract
Light is both the ultimate energy source for most organisms and a rich information source. Vitamin A-based chromophore was initially used in harvesting light energy, but has become the most widely used light sensor throughout evolution from unicellular to multicellular organisms. Vitamin A-based photoreceptor proteins are called opsins and have been used for billions of years for sensing light for vision or the equivalent of vision. All vitamin A-based light sensors for vision in the animal kingdom are G-protein coupled receptors, while those in unicellular organisms are light-gated channels. This first major switch in evolution was followed by two other major changes: the switch from bistable to monostable pigments for vision and the expansion of vitamin A's biological functions. Vitamin A's new functions such as regulating cell growth and differentiation from embryogenesis to adult are associated with increased toxicity with its random diffusion. In contrast to bistable pigments which can be regenerated by light, monostable pigments depend on complex enzymatic cycles for regeneration after every photoisomerization event. Here we discuss vitamin A functions and transport in the context of the natural history of vitamin A-based light sensors and propose that the expanding functions of vitamin A and the choice of monostable pigments are the likely evolutionary driving forces for precise, efficient, and sustained vitamin A transport.
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Affiliation(s)
- Ming Zhong
- Department of Physiology, Jules Stein Eye Institute, and Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
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Rozanowska MB. Light-Induced Damage to the Retina: Current Understanding of the Mechanisms and Unresolved Questions: A Symposium-in-Print. Photochem Photobiol 2012; 88:1303-8. [DOI: 10.1111/j.1751-1097.2012.01240.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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