1
|
Torrissen M, Ytteborg E, Svensen H, Stoknes I, Nilsson A, Østbye TK, Berge GM, Bou M, Ruyter B. Investigation of the functions of n-3 very-long-chain PUFAs in skin using in vivo Atlantic salmon and in vitro human and fish skin models. Br J Nutr 2023; 130:1915-1931. [PMID: 37169355 PMCID: PMC10630148 DOI: 10.1017/s0007114523001150] [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: 12/05/2022] [Revised: 04/03/2023] [Accepted: 05/02/2023] [Indexed: 05/13/2023]
Abstract
The purpose of this study was to investigate the effect of dietary n-3 very-long-chain PUFA (n-3 VLC-PUFA) on the maturation and development of skin tissue in juvenile Atlantic salmon (Salmo salar) in vivo, as well as their effects on skin keratocyte and human skin fibroblast cell migration in vitro. Atlantic salmon were fed different dietary levels of n-3 VLC-PUFA from an initial weight of 6 g to a final weight of 11 g. Changes in skin morphology were analysed at two time points during the experiment, and the effects on skin tissue fatty acid composition were determined. Additionally, in vitro experiments using human dermal fibroblasts and primary Atlantic salmon keratocytes were conducted to investigate the effect of VLC-PUFA on the migration capacity of the cells. The results demonstrated that increased dietary levels of n-3 VLC-PUFA led to an increased epidermis thickness and more rapid scale maturation in Atlantic salmon skin in vivo, leading to a more mature skin morphology, and possibly more robust skin, at an earlier life stage. Additionally, human skin fibroblasts and salmon skin keratocytes supplemented with n-3 VLC-PUFA in vitro showed more rapid migration, indicating potentially beneficial effects of VLC-PUFA in wound healing. In conclusion, VLC-PUFA may have beneficial effects on skin tissue development, function and integrity.
Collapse
Affiliation(s)
- Martina Torrissen
- Nofima (Norwegian Institute of Food, Fisheries and Aquaculture Research), 1432Ås, Norway
- Epax Norway, 6006Ålesund, Norway
- NMBU (Norwegian University of Life Sciences), 1433Ås, Norway
| | - Elisabeth Ytteborg
- Nofima (Norwegian Institute of Food, Fisheries and Aquaculture Research), 1432Ås, Norway
| | | | | | - Astrid Nilsson
- Nofima (Norwegian Institute of Food, Fisheries and Aquaculture Research), 1432Ås, Norway
| | - Tone-Kari Østbye
- Nofima (Norwegian Institute of Food, Fisheries and Aquaculture Research), 1432Ås, Norway
| | - Gerd Marit Berge
- Nofima (Norwegian Institute of Food, Fisheries and Aquaculture Research), 1432Ås, Norway
| | - Marta Bou
- Nofima (Norwegian Institute of Food, Fisheries and Aquaculture Research), 1432Ås, Norway
| | - Bente Ruyter
- Nofima (Norwegian Institute of Food, Fisheries and Aquaculture Research), 1432Ås, Norway
- NMBU (Norwegian University of Life Sciences), 1433Ås, Norway
| |
Collapse
|
2
|
Cheng V, Rallabandi R, Gorusupudi A, Lucas S, Rognon G, Bernstein PS, Rainier JD, Conboy JC. Influence of very-long-chain polyunsaturated fatty acids on membrane structure and dynamics. Biophys J 2022; 121:2730-2741. [PMID: 35711144 DOI: 10.1016/j.bpj.2022.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/24/2022] [Accepted: 06/10/2022] [Indexed: 11/30/2022] Open
Abstract
The unique attributes of very-long-chain polyunsaturated fatty acids (VLC-PUFAs), their long carbon chains (n > 24) and high degree of unsaturation, impart unique chemical and physical properties to this class of fatty acids. The changes imparted by VLC-PUFA 32:6 n-3 on lipid packing and the compression moduli of model membranes were evaluated from π-A isotherms of VLC-PUFA in 1,2-distearoyl-sn-3-glycero-phosphocholine (DSPC) lipid monolayers. To compare the attractive or repulsive forces between VLC-PUFA and DSPC lipid monolayers, the measured mean molecular areas (MMAs) were compared with the calculated MMAs of an ideal mixture of VLC-PUFA and DSPC. The presence of 0.1, 1, and 10 mol % VLC-PUFA shifted the π-A isotherm to higher MMAs of the lipids comprising the membrane and the observed positive deviations from ideal behavior of the mixed VLC-PUFA:DSPC monolayers correspond to repulsive forces between VLC-PUFAs and DSPC. The MMA of the VLC-PUFA component was estimated using the measured MMAs of DSPC of 47.1 ± 0.7 Å2/molecule, to be 15,000, 1100, and 91 Å2/molecule at 0.1, 1, and 10 mol % VLC-PUFA:DSPC mixtures, respectively. The large MMAs of VLC-PUFA suggest that the docosahexaenoic acid tail reinserts into the membrane and adopts a nonlinear structure in the membrane, which is most pronounced at 0.1 mol % VLC-PUFA. The presence of 0.1 mol % VLC-PUFA:DSPC also significantly increased the compression modulus of the membrane by 28 mN/m compared with a pure DSPC membrane. The influence of VLC-PUFA on lipid "flip-flop" was investigated by sum-frequency vibrational spectroscopy. The incorporation of 0.1 mol % VLC-PUFA increased the DSPC flip-flop rate fourfold. The fact that VLC-PUFA promotes lipid translocation is noteworthy as retinal membranes require a high influx of retinoids which may be facilitated by lipid flip-flop.
Collapse
Affiliation(s)
- Victoria Cheng
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | | | - Aruna Gorusupudi
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Steven Lucas
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | - Gregory Rognon
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Paul S Bernstein
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Jon D Rainier
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | - John C Conboy
- Department of Chemistry, University of Utah, Salt Lake City, Utah.
| |
Collapse
|
3
|
Lewandowski D, Sander CL, Tworak A, Gao F, Xu Q, Skowronska-Krawczyk D. Dynamic lipid turnover in photoreceptors and retinal pigment epithelium throughout life. Prog Retin Eye Res 2021; 89:101037. [PMID: 34971765 PMCID: PMC10361839 DOI: 10.1016/j.preteyeres.2021.101037] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/13/2022]
Abstract
The retinal pigment epithelium-photoreceptor interphase is renewed each day in a stunning display of cellular interdependence. While photoreceptors use photosensitive pigments to convert light into electrical signals, the RPE supports photoreceptors in their function by phagocytizing shed photoreceptor tips, regulating the blood retina barrier, and modulating inflammatory responses, as well as regenerating the 11-cis-retinal chromophore via the classical visual cycle. These processes involve multiple protein complexes, tightly regulated ligand-receptors interactions, and a plethora of lipids and protein-lipids interactions. The role of lipids in maintaining a healthy interplay between the RPE and photoreceptors has not been fully delineated. In recent years, novel technologies have resulted in major advancements in understanding several facets of this interplay, including the involvement of lipids in phagocytosis and phagolysosome function, nutrient recycling, and the metabolic dependence between the two cell types. In this review, we aim to integrate the complex role of lipids in photoreceptor and RPE function, emphasizing the dynamic exchange between the cells as well as discuss how these processes are affected in aging and retinal diseases.
Collapse
Affiliation(s)
- Dominik Lewandowski
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Christopher L Sander
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Fangyuan Gao
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Qianlan Xu
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA.
| |
Collapse
|
4
|
Continuous gradient temperature Raman spectroscopy of 1-stearoyl- 2-docosahexaenoyl, 1-stearoyl- 2-arachidonoyl, and 1,2-stearoyl phosphocholines. Chem Phys Lipids 2021; 239:105116. [PMID: 34271000 DOI: 10.1016/j.chemphyslip.2021.105116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 11/23/2022]
Abstract
Mixed chain phospholipids containing a saturated fatty acid at sn1 and a polyunsaturated fatty acid in sn2 are common in the specialized biological membranes prevalent in neural, retinal and organ tissues. Particularly important are mixed lipids containing palmitic or stearic acid and arachidonic or docosahexaenoic acid. Gradient temperature Raman spectroscopy (GTRS) applies the temperature gradients utilized in differential scanning calorimetry to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements and phase transitions. Herein we utilize GTRS for 1-18:0, 2-20:4n-6 PC; 1-18:0 2-22:6n-3 PC; and 1-18:0, 2-18:0 PC from -80 to 50 °C temperatures. 20 Mb three-dimensional data arrays with 0.2 °C increments and first/second derivatives allowed detailed vibrational mode assignment and analysis. Samples were analyzed neat and with molecular hydration. Previously reported phase transitions for hydrated 18:0-20:4PC and 18:0-22:6PC and numerous spectral differences resulting from hydration and the double bond structure were clearly observed. Molecular models showed that the addition of minimal water molecules results in significant structural differences compared to the neat molecules; 18:0-22:6PC is strikingly compact with water when viewed from the hydrophilic end. This precise Raman data cannot be observed in typically utilized fully hydrated vesicle samples, however the improved GTRS will allow for more precise analysis in fully hydrated vesicles because the underlying modes in the unavoidably broadened spectra can be identified.
Collapse
|
5
|
Ruiz-Pastor MJ, Kutsyr O, Lax P, Cuenca N. Decrease in DHA and other fatty acids correlates with photoreceptor degeneration in retinitis pigmentosa. Exp Eye Res 2021; 209:108667. [PMID: 34119484 DOI: 10.1016/j.exer.2021.108667] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/21/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
Abstract
Fatty acids, and especially docosahexaenoic acid (DHA), are essential for photoreceptor cell integrity and are involved in the phototransduction cascade. In this study, we analyzed the changes in the fatty acid profile in the retina of the rd10 mouse, model of retinitis pigmentosa, in order to identify potential risk factors for retinal degeneration and possible therapeutic approaches. Fatty acids from C57BL/6J and rd10 mouse retinas were extracted with Folch's method and analyzed by gas chromatography/mass spectrometry. Changes in retinal morphology were evaluated by immunohistochemistry. The rd10 mouse retina showed a decreased number of photoreceptor rows and alterations in photoreceptor morphology compared to C57BL/6J mice. The total amount of fatty acids dropped by 29.4% in the dystrophic retinas compared to C57BL/6J retinas. A positive correlation was found between the retinal content of specific fatty acids and the number of photoreceptor rows. We found that the amount of several short-chain and long-chain saturated fatty acids, as well as monounsaturated fatty acids, decreased in the retina of rd10 mice. Moreover, the content of the n-6 polyunsaturated fatty acid arachidonic acid and the n-3 polyunsaturated DHA decreased markedly in the dystrophic retina. The fall of DHA was more pronounced, hence the n-6/n-3 ratio was significantly increased in the diseased retina. The content of specific fatty acids in the retina decreased with photoreceptor degeneration in retinitis pigmentosa mice, with a remarkable reduction in DHA and other saturated and unsaturated fatty acids. These fatty acids could be essential for photoreceptor cell viability, and they should be evaluated for the design of therapeutical strategies and nutritional supplements.
Collapse
Affiliation(s)
- María José Ruiz-Pastor
- Department of Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain
| | - Oksana Kutsyr
- Department of Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain
| | - Pedro Lax
- Department of Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain.
| | - Nicolás Cuenca
- Department of Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain.
| |
Collapse
|
6
|
Deposition and metabolism of dietary n-3 very-long-chain PUFA in different organs of rat, mouse and Atlantic salmon. Br J Nutr 2021; 127:35-54. [PMID: 33750483 DOI: 10.1017/s0007114521000817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
There is limited knowledge about the metabolism and function of n-3 very-long-chain PUFA (n-3 VLC-PUFA) with chain lengths ≥ 24. They are known to be produced endogenously in certain tissues from EPA and DHA and not considered to originate directly from dietary sources. The aim of this study was to investigate whether n-3 VLC-PUFA from dietary sources are bio-available and deposited in tissues of rat, fish and mouse. Rats were fed diets supplemented with a natural fish oil (FO) as a source of low dietary levels of n-3 VLC-PUFA, while Atlantic salmon and mice were fed higher dietary levels of n-3 VLC-PUFA from a FO concentrate. In all experiments, n-3 VLC-PUFA incorporation in organs was investigated. We found that natural FO, due to its high EPA content, to a limited extent increased endogenous production of n-3 VLC-PUFA in brain and eye of mice with neglectable amounts of n-3 VLC-PUFA originating from diet. When higher dietary levels were given in the form of concentrate, these fatty acids were bio-available and deposited in both phospholipids and TAG fractions of all tissues studied, including skin, eye, brain, testis, liver and heart, and their distribution appeared to be tissue-dependent, but not species-specific. When dietary EPA and DHA were balanced and n-3 VLC-PUFA increased, the major n-3 VLC-PUFA from the concentrate increased significantly in the organs studied, showing that these fatty acids can be provided through diet and thereby provide a tool for functional studies of these VLC-PUFA.
Collapse
|
7
|
Craig LB, Brush RS, Sullivan MT, Zavy MT, Agbaga MP, Anderson RE. Decreased very long chain polyunsaturated fatty acids in sperm correlates with sperm quantity and quality. J Assist Reprod Genet 2019; 36:1379-1385. [PMID: 31073727 DOI: 10.1007/s10815-019-01464-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 04/26/2019] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To determine if levels of very long chain polyunsaturated fatty acids (VLC-PUFA; ≥ 28 carbons;4-6 double bonds) in human sperm correlate with sperm quantity and quality as determined by a complete semen analysis. METHODS Ejaculates from 70 men underwent a complete semen analysis, which included volume, count, motility, progression, agglutination, viscosity, morphology, and pH. For lipid analysis, sperm were pelleted to remove the semen. Lipids were extracted from the cell pellet and methyl esters of total lipids analyzed by gas chromatography. The sphingolipids were enriched and sphingomyelin (SM) species measured using tandem mass spectrometry. Pair-wise Pearson correlation and linear regression analysis compared percent VLC-PUFA-SM and percent docosahexaenoic acid (DHA) to results from the semen analysis. RESULTS VLC-PUFA-SM species having 28-34 carbon fatty acids were detected in sperm samples, with 28 and 30 carbon VLC-PUFA as most the abundant. The sum of all VLC-PUFA-SM species comprised 0 to 6.1% of the overall SM pool (mean 2.1%). Pair-wise Pearson analyses showed that lower levels of VLC-PUFA-SM positively correlated with lower total motile count (0.68) and lower total count (0.67). Total VLC-PUFA-SM and mole % DHA (22:6n3) were not strongly correlated (- 0.24). Linear regression analysis confirmed these findings. CONCLUSION This study revealed a positive correlation between the levels of VLC-PUFA with sperm count and total motile count and suggests that both sperm quality and quantity may depend on the presence of VLC-PUFA. The lack of correlation between VLC-PUFA and DHA suggests that low VLC-PUFA levels do not result from inadequate PUFA precursors.
Collapse
Affiliation(s)
- LaTasha B Craig
- Section of Reproductive Endocrinology & Infertility, Department of Obstetrics and Gynecology, College of Medicine, University of Oklahoma Health Sciences Center, PO Box 26901, AAT 2400, Oklahoma City, OK, 73126, USA.
| | - Richard S Brush
- Department of Ophthalmology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.,Dean A. McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | - Michael T Sullivan
- Department of Ophthalmology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.,Dean A. McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | - Michael T Zavy
- Section of Reproductive Endocrinology & Infertility, Department of Obstetrics and Gynecology, College of Medicine, University of Oklahoma Health Sciences Center, PO Box 26901, AAT 2400, Oklahoma City, OK, 73126, USA
| | - Martin-Paul Agbaga
- Department of Ophthalmology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.,Dean A. McGee Eye Institute, Oklahoma City, OK, 73104, USA.,Department of Cell Biology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Robert E Anderson
- Department of Ophthalmology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.,Dean A. McGee Eye Institute, Oklahoma City, OK, 73104, USA.,Department of Cell Biology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| |
Collapse
|
8
|
Donato L, Bramanti P, Scimone C, Rinaldi C, Giorgianni F, Beranova-Giorgianni S, Koirala D, D'Angelo R, Sidoti A. miRNAexpression profile of retinal pigment epithelial cells under oxidative stress conditions. FEBS Open Bio 2018; 8:219-233. [PMID: 29435412 PMCID: PMC5794457 DOI: 10.1002/2211-5463.12360] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 11/03/2017] [Accepted: 11/24/2017] [Indexed: 12/22/2022] Open
Abstract
Deep analysis of regulative mechanisms of transcription and translation in eukaryotes could improve knowledge of many genetic pathologies such as retinitis pigmentosa (RP). New layers of complexity have recently emerged with the discovery that ‘junk’ DNA is transcribed and, among these, miRNAs have assumed a preponderant role. We compared changes in the expression of miRNAs obtained from whole transcriptome analyses, between two groups of retinal pigment epithelium (RPE) cells, one untreated and the other exposed to the oxidant agent oxidized low‐density lipoprotein (oxLDL), examining four time points (1, 2, 4 and 6 h). We found that 23 miRNAs exhibited altered expression in the treated samples, targeting genes involved in several biochemical pathways, many of them associated to RP for the first time, such as those mediated by insulin receptor signaling and son of sevenless. Moreover, five RP causative genes (KLHL7, RDH11,CERKL, AIPL1 and USH1G) emerged as already validated targets of five altered miRNAs (hsa‐miR‐1307, hsa‐miR‐3064, hsa‐miR‐4709, hsa‐miR‐3615 and hsa‐miR‐637), suggesting a tight connection between induced oxidative stress and RP development and progression. This miRNA expression analysis of oxidative stress‐induced RPE cells has discovered new regulative functions of miRNAs in RP that should lead to the discovery of new ways to regulate the etiopathogenesis of RP.
Collapse
Affiliation(s)
- Luigi Donato
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging Division of Medical Biotechnologies and Preventive Medicine University of Messina Italy.,Department of Cutting-Edge Medicine and Therapies Biomolecular Strategies and Neuroscience Section of Neuroscience-applied, Molecular Genetics and Predictive MedicineI.E.M E.S.T. Palermo Italy
| | | | - Concetta Scimone
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging Division of Medical Biotechnologies and Preventive Medicine University of Messina Italy.,Department of Cutting-Edge Medicine and Therapies Biomolecular Strategies and Neuroscience Section of Neuroscience-applied, Molecular Genetics and Predictive MedicineI.E.M E.S.T. Palermo Italy
| | - Carmela Rinaldi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging Division of Medical Biotechnologies and Preventive Medicine University of Messina Italy
| | | | | | | | - Rosalia D'Angelo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging Division of Medical Biotechnologies and Preventive Medicine University of Messina Italy
| | - Antonina Sidoti
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging Division of Medical Biotechnologies and Preventive Medicine University of Messina Italy.,Department of Cutting-Edge Medicine and Therapies Biomolecular Strategies and Neuroscience Section of Neuroscience-applied, Molecular Genetics and Predictive MedicineI.E.M E.S.T. Palermo Italy
| |
Collapse
|
9
|
Ail D, Perron M. Retinal Degeneration and Regeneration-Lessons From Fishes and Amphibians. CURRENT PATHOBIOLOGY REPORTS 2017; 5:67-78. [PMID: 28255526 PMCID: PMC5309292 DOI: 10.1007/s40139-017-0127-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Retinal degenerative diseases have immense socio-economic impact. Studying animal models that recapitulate human eye pathologies aids in understanding the pathogenesis of diseases and allows for the discovery of novel therapeutic strategies. Some non-mammalian species are known to have remarkable regenerative abilities and may provide the basis to develop strategies to stimulate self-repair in patients suffering from these retinal diseases. RECENT FINDINGS Non-mammalian organisms, such as zebrafish and Xenopus, have become attractive model systems to study retinal diseases. Additionally, many fish and amphibian models of retinal cell ablation and cell lineage analysis have been developed to study regeneration. These investigations highlighted several cellular sources for retinal repair in different fish and amphibian species. Moreover, major differences in repair mechanisms have been reported in these animal models. SUMMARY This review aims to emphasize first on the importance of zebrafish and Xenopus models in studying the pathogenesis of retinal diseases and, second, on the different modes of regeneration processes in these model organisms.
Collapse
Affiliation(s)
- Divya Ail
- Paris-Saclay Institute of Neuroscience, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Muriel Perron
- Paris-Saclay Institute of Neuroscience, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Orsay, France
- Centre d’Etude et de Recherche Thérapeutique en Ophtalmologie, Retina France, Orsay, France
| |
Collapse
|
10
|
Albert A, Alexander D, Boesze-Battaglia K. Cholesterol in the rod outer segment: A complex role in a "simple" system. Chem Phys Lipids 2016; 199:94-105. [PMID: 27216754 DOI: 10.1016/j.chemphyslip.2016.04.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/22/2016] [Accepted: 04/23/2016] [Indexed: 12/01/2022]
Abstract
The rod outer segment (ROS) of retinal photoreceptor cells consists of disk membranes surrounded by the plasma membrane. It is a relatively uncomplicated system in which to investigate cholesterol distribution and its functional consequences in biologically relevant membranes. The light sensitive protein, rhodopsin is the major protein in both membranes, but the lipid compositions are significantly different in the disk and plasma membranes. Cholesterol is high in the ROS plasma membrane. Disk membranes are synthesized at the base of the ROS and are also high in cholesterol. However, cholesterol is rapidly depleted as the disks are apically displaced. During this apical displacement the disk phospholipid fatty acyl chains become progressively more unsaturated, which creates an environment unfavorable to cholesterol. Membrane cholesterol has functional consequences. The high cholesterol found in the plasma membrane and in newly synthesized disks inhibits the activation of rhodopsin. As disks are apically displaced and cholesterol is depleted rhodopsin becomes more responsive to light. This effect of cholesterol on rhodopsin activation has been shown in both native and reconstituted membranes. The modulation of activity can be at least partially explained by the effect of cholesterol on bulk lipid properties. Cholesterol decreases the partial free volume of the hydrocarbon region of the bilayer and thereby inhibits rhodopsin conformational changes required for activation. However, cholesterol binds to rhodopsin and may directly affect the protein also. Furthermore, cholesterol stabilizes rhodopsin to thermal denaturation. The membrane must provide an environment that allows rhodopsin conformational changes required for activation while also stabilizing the protein to thermal denaturation. Cholesterol thus plays a complex role in modulating the activity and stability of rhodopsin, which have implications for other G-protein coupled receptors.
Collapse
|