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Pinelli R, Ferrucci M, Biagioni F, Berti C, Bumah VV, Busceti CL, Puglisi-Allegra S, Lazzeri G, Frati A, Fornai F. Autophagy Activation Promoted by Pulses of Light and Phytochemicals Counteracting Oxidative Stress during Age-Related Macular Degeneration. Antioxidants (Basel) 2023; 12:1183. [PMID: 37371913 DOI: 10.3390/antiox12061183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/15/2023] [Accepted: 05/27/2023] [Indexed: 06/29/2023] Open
Abstract
The seminal role of autophagy during age-related macular degeneration (AMD) lies in the clearance of a number of reactive oxidative species that generate dysfunctional mitochondria. In fact, reactive oxygen species (ROS) in the retina generate misfolded proteins, alter lipids and sugars composition, disrupt DNA integrity, damage cell organelles and produce retinal inclusions while causing AMD. This explains why autophagy in the retinal pigment epithelium (RPE), mostly at the macular level, is essential in AMD and even in baseline conditions to provide a powerful and fast replacement of oxidized molecules and ROS-damaged mitochondria. When autophagy is impaired within RPE, the deleterious effects of ROS, which are produced in excess also during baseline conditions, are no longer counteracted, and retinal degeneration may occur. Within RPE, autophagy can be induced by various stimuli, such as light and naturally occurring phytochemicals. Light and phytochemicals, in turn, may synergize to enhance autophagy. This may explain the beneficial effects of light pulses combined with phytochemicals both in improving retinal structure and visual acuity. The ability of light to activate some phytochemicals may further extend such a synergism during retinal degeneration. In this way, photosensitive natural compounds may produce light-dependent beneficial antioxidant effects in AMD.
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Affiliation(s)
- Roberto Pinelli
- SERI, Switzerland Eye Research Institute, 6900 Lugano, Switzerland
| | - Michela Ferrucci
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Francesca Biagioni
- IRCCS, Istituto di Ricovero e Cura a Carattere Scientifico, Neuromed, 86077 Pozzili, Italy
| | - Caterina Berti
- SERI, Switzerland Eye Research Institute, 6900 Lugano, Switzerland
| | - Violet Vakunseth Bumah
- Department of Chemistry and Biochemistry, College of Sciences, San Diego State University, San Diego, CA 92182, USA
- Department of Chemistry and Physics, University of Tennessee, Martin, TN 38237, USA
| | - Carla Letizia Busceti
- IRCCS, Istituto di Ricovero e Cura a Carattere Scientifico, Neuromed, 86077 Pozzili, Italy
| | | | - Gloria Lazzeri
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Alessandro Frati
- IRCCS, Istituto di Ricovero e Cura a Carattere Scientifico, Neuromed, 86077 Pozzili, Italy
| | - Francesco Fornai
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
- IRCCS, Istituto di Ricovero e Cura a Carattere Scientifico, Neuromed, 86077 Pozzili, Italy
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Pinelli R, Ferrucci M, Berti C, Biagioni F, Scaffidi E, Bumah VV, Busceti CL, Lenzi P, Lazzeri G, Fornai F. The Essential Role of Light-Induced Autophagy in the Inner Choroid/Outer Retinal Neurovascular Unit in Baseline Conditions and Degeneration. Int J Mol Sci 2023; 24:ijms24108979. [PMID: 37240326 DOI: 10.3390/ijms24108979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/26/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
The present article discusses the role of light in altering autophagy, both within the outer retina (retinal pigment epithelium, RPE, and the outer segment of photoreceptors) and the inner choroid (Bruch's membrane, BM, endothelial cells and the pericytes of choriocapillaris, CC). Here autophagy is needed to maintain the high metabolic requirements and to provide the specific physiological activity sub-serving the process of vision. Activation or inhibition of autophagy within RPE strongly depends on light exposure and it is concomitant with activation or inhibition of the outer segment of the photoreceptors. This also recruits CC, which provides blood flow and metabolic substrates. Thus, the inner choroid and outer retina are mutually dependent and their activity is orchestrated by light exposure in order to cope with metabolic demand. This is tuned by the autophagy status, which works as a sort of pivot in the cross-talk within the inner choroid/outer retina neurovascular unit. In degenerative conditions, and mostly during age-related macular degeneration (AMD), autophagy dysfunction occurs in this area to induce cell loss and extracellular aggregates. Therefore, a detailed analysis of the autophagy status encompassing CC, RPE and interposed BM is key to understanding the fine anatomy and altered biochemistry which underlie the onset and progression of AMD.
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Affiliation(s)
- Roberto Pinelli
- Switzerland Eye Research Institute (SERI), 6900 Lugano, Switzerland
| | - Michela Ferrucci
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Caterina Berti
- Switzerland Eye Research Institute (SERI), 6900 Lugano, Switzerland
| | - Francesca Biagioni
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 86077 Pozzili, Italy
| | - Elena Scaffidi
- Switzerland Eye Research Institute (SERI), 6900 Lugano, Switzerland
| | - Violet Vakunseth Bumah
- Department of Chemistry and Biochemistry College of Sciences San Diego State University, San Diego, CA 92182, USA
- Department of Chemistry and Physics, University of Tennessee, Knoxville, TN 37996, USA
| | - Carla L Busceti
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 86077 Pozzili, Italy
| | - Paola Lenzi
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Gloria Lazzeri
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Francesco Fornai
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 86077 Pozzili, Italy
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3
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Parmar T, Ortega JT, Jastrzebska B. Retinoid analogs and polyphenols as potential therapeutics for age-related macular degeneration. Exp Biol Med (Maywood) 2020; 245:1615-1625. [PMID: 32438835 PMCID: PMC7787542 DOI: 10.1177/1535370220926938] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
IMPACT STATEMENT Age-related macular degeneration (AMD) is a devastating retinal degenerative disease. Epidemiological reports showed an expected increasing prevalence of AMD in the near future. The only one existing FDA-approved pharmacological treatment involves an anti-vascular endothelial growth factor (VEGF) therapy with serious disadvantages. This limitation emphasizes an alarming need to develop new therapeutic approaches to prevent and treat AMD. In this review, we summarize scientific data unraveling the therapeutic potential of the specific retinoid and natural compounds. The experimental results reported by us and other research groups demonstrated that retinoid analogs and compounds with natural product scaffolds could serve as lead compounds for the development of new therapeutic agents with potential to prevent or slow down the pathogenesis of AMD.
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Affiliation(s)
- Tanu Parmar
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Joseph T Ortega
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Beata Jastrzebska
- Department of Pharmacology, and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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Tisi A, Passacantando M, Lozzi L, Maccarone R. Cerium oxide nanoparticles reduce the accumulation of autofluorescent deposits in light-induced retinal degeneration: Insights for age-related macular degeneration. Exp Eye Res 2020; 199:108169. [PMID: 32758489 DOI: 10.1016/j.exer.2020.108169] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 07/10/2020] [Accepted: 07/26/2020] [Indexed: 01/05/2023]
Abstract
Accumulation of lipofuscin deposits in the retinal pigment epithelium (RPE) is one of the main events involved in age-related macular degeneration and its increase together with RPE dysfunction, blood retinal barrier disruption and photoreceptors death progressively leads to blindness. Lipofuscin is the main autofluorescent (AF) component of the retina and therapies to counteract its deposition are a main goal to be achieved, since effective treatments have not yet been identified. Here, we first investigated the spatio-temporal pattern of AF deposits accumulation in the light-damage model of age-related macular degeneration. Afterward, we tested the ability of cerium oxide nanoparticles, a well known anti-oxidant agent, to counteract AF granules accumulation. The treatment was performed both before and after the induction of the degeneration. AF granules were quantified by confocal microscopy on whole mounted retinas. We demonstrated that the acute light-damage increases the accumulation of AF deposits in the hot spot retina in terms of number of granules and percentage of occupied area, with a peak 7 days after the exposure. Remarkably, cerium oxide nanoparticles showed a strong efficacy in preventing the formation of AF deposits when they were injected 3 days before light exposure. Moreover, when the treatment was performed 7 days after light exposure, nanoceria activity was found to be effective also in reducing the amount of the AF granules still deposited up to 60 days. These important results represent the very first evidence about the ability of cerium oxide nanoparticles to counteract AF deposits accumulation in retinal degeneration, laying the foundations for the development of a new therapy possibly targeting lipofuscin in AMD.
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Affiliation(s)
- A Tisi
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, via Vetoio, Coppito 2, 67100, L'Aquila, Italy.
| | - M Passacantando
- Department of Physical and Chemical Science, University of L'Aquila, via Vetoio, Coppito 1, 67100, L'Aquila, Italy.
| | - L Lozzi
- Department of Physical and Chemical Science, University of L'Aquila, via Vetoio, Coppito 1, 67100, L'Aquila, Italy.
| | - R Maccarone
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, via Vetoio, Coppito 2, 67100, L'Aquila, Italy.
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Cunningham F, Van Bergen T, Canning P, Lengyel I, Feyen JHM, Stitt AW. The Placental Growth Factor Pathway and Its Potential Role in Macular Degenerative Disease. Curr Eye Res 2019; 44:813-822. [PMID: 31055948 DOI: 10.1080/02713683.2019.1614197] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
There is growing evidence that placental growth factor (PlGF) is an important player in multiple pathologies, including tumorigenesis, inflammatory disorders and degenerative retinopathies. PlGF is a member of the vascular endothelial growth factor (VEGF) family and in the retina, binding of this growth factor to specific receptors is associated with pathological angiogenesis, vascular leakage, neurodegeneration and inflammation. Although they share some receptor signalling pathways, many of the actions of PlGF are distinct from VEGF and this has revealed the enticing prospect that it could be a useful therapeutic target for treating early and late stages of diabetic retinopathy (DR) and neovascular age-related macular degeneration (AMD). Recent research suggests that modulation of PlGF could also be important in the geographic atrophy (GA) form of late AMD by protecting the outer retina and the retinal pigment epithelium (RPE). This review discusses PlGF and its signalling pathways and highlights the potential of blocking the bioactivity of this growth factor to treat irreversible visual loss due to the two main forms of AMD.
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Affiliation(s)
- Fiona Cunningham
- a Centre for Experimental Medicine, Queen's University Belfast , Belfast , Northern Ireland
| | | | - Paul Canning
- a Centre for Experimental Medicine, Queen's University Belfast , Belfast , Northern Ireland
| | - Imre Lengyel
- a Centre for Experimental Medicine, Queen's University Belfast , Belfast , Northern Ireland
| | | | - Alan W Stitt
- a Centre for Experimental Medicine, Queen's University Belfast , Belfast , Northern Ireland
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A Brain-Derived Neurotrophic Factor Mimetic Is Sufficient to Restore Cone Photoreceptor Visual Function in an Inherited Blindness Model. Sci Rep 2017; 7:11320. [PMID: 28900183 PMCID: PMC5595969 DOI: 10.1038/s41598-017-11513-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 08/25/2017] [Indexed: 01/25/2023] Open
Abstract
Controversially, histone deacetylase inhibitors (HDACi) are in clinical trial for the treatment of inherited retinal degeneration. Utilizing the zebrafish dyeucd6 model, we determined if treatment with HDACi can rescue cone photoreceptor-mediated visual function. dye exhibit defective visual behaviour and retinal morphology including ciliary marginal zone (CMZ) cell death and decreased photoreceptor outer segment (OS) length, as well as gross morphological defects including hypopigmentation and pericardial oedema. HDACi treatment of dye results in significantly improved optokinetic (OKR) (~43 fold, p < 0.001) and visualmotor (VMR) (~3 fold, p < 0.05) responses. HDACi treatment rescued gross morphological defects and reduced CMZ cell death by 80%. Proteomic analysis of dye eye extracts suggested BDNF-TrkB and Akt signaling as mediators of HDACi rescue in our dataset. Co-treatment with the TrkB antagonist ANA-12 blocked HDACi rescue of visual function and associated Akt phosphorylation. Notably, sole treatment with a BDNF mimetic, 7,8-dihydroxyflavone hydrate, significantly rescued dye visual function (~58 fold increase in OKR, p < 0.001, ~3 fold increase in VMR, p < 0.05). In summary, HDACi and a BDNF mimetic are sufficient to rescue retinal cell death and visual function in a vertebrate model of inherited blindness.
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Capozzi ME, Gordon AY, Penn JS, Jayagopal A. Molecular imaging of retinal disease. J Ocul Pharmacol Ther 2013; 29:275-86. [PMID: 23421501 DOI: 10.1089/jop.2012.0279] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Imaging of the eye plays an important role in ocular therapeutic discovery and evaluation in preclinical models and patients. Advances in ophthalmic imaging instrumentation have enabled visualization of the retina at an unprecedented resolution. These developments have contributed toward early detection of the disease, monitoring of disease progression, and assessment of the therapeutic response. These powerful technologies are being further harnessed for clinical applications by configuring instrumentation to detect disease biomarkers in the retina. These biomarkers can be detected either by measuring the intrinsic imaging contrast in tissue, or by the engineering of targeted injectable contrast agents for imaging of the retina at the cellular and molecular level. Such approaches have promise in providing a window on dynamic disease processes in the retina such as inflammation and apoptosis, enabling translation of biomarkers identified in preclinical and clinical studies into useful diagnostic targets. We discuss recently reported and emerging imaging strategies for visualizing diverse cell types and molecular mediators of the retina in vivo during health and disease, and the potential for clinical translation of these approaches.
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Affiliation(s)
- Megan E Capozzi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-8808, USA
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Biswas-Fiss EE, Affet S, Ha M, Biswas SB. Retinoid binding properties of nucleotide binding domain 1 of the Stargardt disease-associated ATP binding cassette (ABC) transporter, ABCA4. J Biol Chem 2012; 287:44097-107. [PMID: 23144455 DOI: 10.1074/jbc.m112.409623] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The retina-specific ATP binding cassette transporter, ABCA4 protein, is associated with a broad range of inherited macular degenerations, including Stargardt disease, autosomal recessive cone rod dystrophy, and fundus flavimaculatus. In order to understand its role in retinal transport in rod out segment discs, we have investigated the interactions of the soluble domains of ABCA4 with both 11-cis- and all-trans-retinal. Using fluorescence anisotropy-based binding analysis and recombinant polypeptides derived from the amino acid sequences of the four soluble domains of ABCA4, we demonstrated that the nucleotide binding domain 1 (NBD1) specifically bound 11-cis-retinal. Its affinity for all-trans-retinal was markedly reduced. Stargardt disease-associated mutations in this domain resulted in attenuation of 11-cis-retinal binding. Significant differences in 11-cis-retinal binding affinities were observed between NBD1 and other cytoplasmic and lumenal domains of ABCA4. The results suggest a possible role of ABCA4 and, in particular, the NBD1 domain in 11-cis-retinal binding. These results also correlate well with a recent report on the in vivo role of ABCA4 in 11-cis-retinal transport.
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Affiliation(s)
- Esther E Biswas-Fiss
- Department of Bioscience Technologies, Program in Biotechnology, Jefferson School of Health Professions, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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9
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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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10
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Tang PH, Kono M, Koutalos Y, Ablonczy Z, Crouch RK. New insights into retinoid metabolism and cycling within the retina. Prog Retin Eye Res 2012; 32:48-63. [PMID: 23063666 DOI: 10.1016/j.preteyeres.2012.09.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Revised: 09/28/2012] [Accepted: 09/30/2012] [Indexed: 01/05/2023]
Abstract
The retinoid cycle is a series of biochemical reactions within the eye that is responsible for synthesizing the chromophore, 11-cis retinal, for visual function. The chromophore is bound to G-protein coupled receptors, opsins, within rod and cone photoreceptor cells forming the photosensitive visual pigments. Integral to the sustained function of photoreceptors is the continuous generation of chromophore by the retinoid cycle through two separate processes, one that supplies both rods and cones and another that exclusively supplies cones. Recent findings such as RPE65 localization within cones and the pattern of distribution of retinoid metabolites within mouse and human retinas have challenged previous proposed schemes. This review will focus on recent findings regarding the transport of retinoids, the mechanisms by which chromophore is supplied to both rods and cones, and the metabolism of retinoids within the posterior segment of the eye.
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Affiliation(s)
- Peter H Tang
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
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Boyer NP, Higbee D, Currin MB, Blakeley LR, Chen C, Ablonczy Z, Crouch RK, Koutalos Y. Lipofuscin and N-retinylidene-N-retinylethanolamine (A2E) accumulate in retinal pigment epithelium in absence of light exposure: their origin is 11-cis-retinal. J Biol Chem 2012; 287:22276-86. [PMID: 22570475 DOI: 10.1074/jbc.m111.329235] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The age-dependent accumulation of lipofuscin in the retinal pigment epithelium (RPE) has been associated with the development of retinal diseases, particularly age-related macular degeneration and Stargardt disease. A major component of lipofuscin is the bis-retinoid N-retinylidene-N-retinylethanolamine (A2E). The current model for the formation of A2E requires photoactivation of rhodopsin and subsequent release of all-trans-retinal. To understand the role of light exposure in the accumulation of lipofuscin and A2E, we analyzed RPEs and isolated rod photoreceptors from mice of different ages and strains, reared either in darkness or cyclic light. Lipofuscin levels were determined by fluorescence imaging, whereas A2E levels were quantified by HPLC and UV-visible absorption spectroscopy. The identity of A2E was confirmed by tandem mass spectrometry. Lipofuscin and A2E levels in the RPE increased with age and more so in the Stargardt model Abca4(-/-) than in the wild type strains 129/sv and C57Bl/6. For each strain, the levels of lipofuscin precursor fluorophores in dark-adapted rods and the levels and rates of increase of RPE lipofuscin and A2E were not different between dark-reared and cyclic light-reared animals. Both 11-cis- and all-trans-retinal generated lipofuscin-like fluorophores when added to metabolically compromised rod outer segments; however, it was only 11-cis-retinal that generated such fluorophores when added to metabolically intact rods. The results suggest that lipofuscin originates from the free 11-cis-retinal that is continuously supplied to the rod for rhodopsin regeneration and outer segment renewal. The physiological role of Abca4 may include the translocation of 11-cis-retinal complexes across the disk membrane.
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Affiliation(s)
- Nicholas P Boyer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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