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Steven K. Fisher - One of the best experts on this subject based on the ideXlab platform.
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Research Article Proteomic Analysis of the Vitreous following Experimental Retinal Detachment in Rabbits
2016Co-Authors: Nakul M, Geoffrey P. Lewis, Steven K. Fisher, Steffen Heegaard, Jan U. Prause, Morten La Cour, Henrik Vorum, Bent HonoréAbstract:Copyright © 2015 Nakul Mandal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose. The pathogenesis of rhegmatogenous Retinal Detachment (RRD) remains incompletely understood, with no clinically effective treatment for potentially severe complications such as photoreceptor cell death and proliferative vitreoretinopathy. Here we investigate the protein profile of the vitreous following Experimental Retinal Detachment using a comparative proteomic based approach.Materials andMethods. Retinal Detachment was created in the right eyes of six NewZealand red pigmented rabbits. Sham surgery was undertaken in five other rabbits that were used as controls. After seven days the eyes were enucleated and the vitreous was removed. The vitreous samples were evaluated with two-dimensional polyacrylamide gel electrophoresis and the differentially expressed proteins were identified with tandem mass spectrometry. Results. Ten protein spots were found to be at least twofold differentially expressed when comparing the vitreous samples of the sham and Retinal Detachment surgery groups. Protein spots that were upregulated in the vitreous following Retinal Detachment were identified as albumin fragments, and those downregulate
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Proteomic Analysis of the Vitreous following Experimental Retinal Detachment in Rabbits
Hindawi Limited, 2015Co-Authors: Nakul Mandal, Geoffrey P. Lewis, Steven K. Fisher, Steffen Heegaard, Jan U. Prause, Morten La Cour, Henrik Vorum, Bent HonoréAbstract:Purpose. The pathogenesis of rhegmatogenous Retinal Detachment (RRD) remains incompletely understood, with no clinically effective treatment for potentially severe complications such as photoreceptor cell death and proliferative vitreoretinopathy. Here we investigate the protein profile of the vitreous following Experimental Retinal Detachment using a comparative proteomic based approach. Materials and Methods. Retinal Detachment was created in the right eyes of six New Zealand red pigmented rabbits. Sham surgery was undertaken in five other rabbits that were used as controls. After seven days the eyes were enucleated and the vitreous was removed. The vitreous samples were evaluated with two-dimensional polyacrylamide gel electrophoresis and the differentially expressed proteins were identified with tandem mass spectrometry. Results. Ten protein spots were found to be at least twofold differentially expressed when comparing the vitreous samples of the sham and Retinal Detachment surgery groups. Protein spots that were upregulated in the vitreous following Retinal Detachment were identified as albumin fragments, and those downregulated were found to be peroxiredoxin 2, collagen-Iα1 fragment, and α-1-antiproteinase F. Conclusions. Proteomic investigation of the rabbit vitreous has identified a set of proteins that help further our understanding of the pathogenesis of rhegmatogenous Retinal Detachment and its complications
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remodelling of Retinal on and off bipolar cells following Experimental Retinal Detachment
Clinical and Experimental Ophthalmology, 2014Co-Authors: Geoffrey P. Lewis, Tsutomu Sakai, Hiroshi Tsuneoka, Steven K. FisherAbstract:Background To study the response of ON and OFF bipolar cells in Experimental Retinal Detachment. Methods Domestic cat retinas were detached for 7 days. The retinas were prepared for immunocytochemical staining with antibodies to Go alpha (α), glutamate transporter GLT-1, protein kinase C and rod opsin, which serve as markers for ON bipolar cells, OFF bipolar cells, rod bipolar cells and rod photoreceptors, respectively. Both sections and whole-mounts were labelled with antibodies to Goα and GLT-1. Results Following 7 days of Detachment, ON bipolar cell processes extended into the outer nuclear layer and had neurites extending beyond their target layer into the inner plexiform layer. In contrast, OFF bipolar cell processes were reduced in the outer plexiform layer following Detachment. Conclusion ON and OFF bipolar cells undergo significant remodelling of their processes in response to Retinal Detachment, and the ON and OFF pathways may be differentially affected. The remodelling may be due to morphological changes that have previously been shown to occur in photoreceptor synaptic terminals or as a result of loss of synaptic connections due to photoreceptor cell death.
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Remodelling of Retinal on‐ and off‐bipolar cells following Experimental Retinal Detachment
Clinical & experimental ophthalmology, 2013Co-Authors: Tsutomu Sakai, Geoffrey P. Lewis, Hiroshi Tsuneoka, Steven K. FisherAbstract:Background To study the response of ON and OFF bipolar cells in Experimental Retinal Detachment. Methods Domestic cat retinas were detached for 7 days. The retinas were prepared for immunocytochemical staining with antibodies to Go alpha (α), glutamate transporter GLT-1, protein kinase C and rod opsin, which serve as markers for ON bipolar cells, OFF bipolar cells, rod bipolar cells and rod photoreceptors, respectively. Both sections and whole-mounts were labelled with antibodies to Goα and GLT-1. Results Following 7 days of Detachment, ON bipolar cell processes extended into the outer nuclear layer and had neurites extending beyond their target layer into the inner plexiform layer. In contrast, OFF bipolar cell processes were reduced in the outer plexiform layer following Detachment. Conclusion ON and OFF bipolar cells undergo significant remodelling of their processes in response to Retinal Detachment, and the ON and OFF pathways may be differentially affected. The remodelling may be due to morphological changes that have previously been shown to occur in photoreceptor synaptic terminals or as a result of loss of synaptic connections due to photoreceptor cell death.
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FGFR1, Signaling, and AP-1 Expression after Retinal Detachment: Reactive Müller and RPE Cells
2013Co-Authors: Scott F. Geller, Geoffrey P. Lewis, Steven K. FisherAbstract:PURPOSE. To identify changes in cellular signaling pathways and AP-1 expression in retina and Retinal pigmented epithelium (RPE) after Experimental Retinal Detachment (RD). METHODS. Cat and rabbit neural retinas were separated from the RPE in vivo for 5 minutes to 28 days. Tissues were removed and processed for Western blotting, immunohistochemistry, in situ hybridization, and immunoprecipitation experiments. RESULTS. An ordered sequence of events occurs after RD: (1) fibroblast growth factor (FGF) receptor 1 (FGFR1, flg) is phosphorylated in the retina within 15 minutes and dephosphorylated 2 hours after RD; (2) The extracellular signal-regulated kinase (ERK) is phosphorylated in both Müller and RPE cells within 15 minutes and remains so for several days; (3) De novo expression of c-fos mRNA coincides with increased c-Fos and c-Jun immunoreactivity in both Müller and RPE cells; (4) CRE
Geoffrey P. Lewis - One of the best experts on this subject based on the ideXlab platform.
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Research Article Proteomic Analysis of the Vitreous following Experimental Retinal Detachment in Rabbits
2016Co-Authors: Nakul M, Geoffrey P. Lewis, Steven K. Fisher, Steffen Heegaard, Jan U. Prause, Morten La Cour, Henrik Vorum, Bent HonoréAbstract:Copyright © 2015 Nakul Mandal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose. The pathogenesis of rhegmatogenous Retinal Detachment (RRD) remains incompletely understood, with no clinically effective treatment for potentially severe complications such as photoreceptor cell death and proliferative vitreoretinopathy. Here we investigate the protein profile of the vitreous following Experimental Retinal Detachment using a comparative proteomic based approach.Materials andMethods. Retinal Detachment was created in the right eyes of six NewZealand red pigmented rabbits. Sham surgery was undertaken in five other rabbits that were used as controls. After seven days the eyes were enucleated and the vitreous was removed. The vitreous samples were evaluated with two-dimensional polyacrylamide gel electrophoresis and the differentially expressed proteins were identified with tandem mass spectrometry. Results. Ten protein spots were found to be at least twofold differentially expressed when comparing the vitreous samples of the sham and Retinal Detachment surgery groups. Protein spots that were upregulated in the vitreous following Retinal Detachment were identified as albumin fragments, and those downregulate
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Proteomic Analysis of the Vitreous following Experimental Retinal Detachment in Rabbits
Hindawi Limited, 2015Co-Authors: Nakul Mandal, Geoffrey P. Lewis, Steven K. Fisher, Steffen Heegaard, Jan U. Prause, Morten La Cour, Henrik Vorum, Bent HonoréAbstract:Purpose. The pathogenesis of rhegmatogenous Retinal Detachment (RRD) remains incompletely understood, with no clinically effective treatment for potentially severe complications such as photoreceptor cell death and proliferative vitreoretinopathy. Here we investigate the protein profile of the vitreous following Experimental Retinal Detachment using a comparative proteomic based approach. Materials and Methods. Retinal Detachment was created in the right eyes of six New Zealand red pigmented rabbits. Sham surgery was undertaken in five other rabbits that were used as controls. After seven days the eyes were enucleated and the vitreous was removed. The vitreous samples were evaluated with two-dimensional polyacrylamide gel electrophoresis and the differentially expressed proteins were identified with tandem mass spectrometry. Results. Ten protein spots were found to be at least twofold differentially expressed when comparing the vitreous samples of the sham and Retinal Detachment surgery groups. Protein spots that were upregulated in the vitreous following Retinal Detachment were identified as albumin fragments, and those downregulated were found to be peroxiredoxin 2, collagen-Iα1 fragment, and α-1-antiproteinase F. Conclusions. Proteomic investigation of the rabbit vitreous has identified a set of proteins that help further our understanding of the pathogenesis of rhegmatogenous Retinal Detachment and its complications
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remodelling of Retinal on and off bipolar cells following Experimental Retinal Detachment
Clinical and Experimental Ophthalmology, 2014Co-Authors: Geoffrey P. Lewis, Tsutomu Sakai, Hiroshi Tsuneoka, Steven K. FisherAbstract:Background To study the response of ON and OFF bipolar cells in Experimental Retinal Detachment. Methods Domestic cat retinas were detached for 7 days. The retinas were prepared for immunocytochemical staining with antibodies to Go alpha (α), glutamate transporter GLT-1, protein kinase C and rod opsin, which serve as markers for ON bipolar cells, OFF bipolar cells, rod bipolar cells and rod photoreceptors, respectively. Both sections and whole-mounts were labelled with antibodies to Goα and GLT-1. Results Following 7 days of Detachment, ON bipolar cell processes extended into the outer nuclear layer and had neurites extending beyond their target layer into the inner plexiform layer. In contrast, OFF bipolar cell processes were reduced in the outer plexiform layer following Detachment. Conclusion ON and OFF bipolar cells undergo significant remodelling of their processes in response to Retinal Detachment, and the ON and OFF pathways may be differentially affected. The remodelling may be due to morphological changes that have previously been shown to occur in photoreceptor synaptic terminals or as a result of loss of synaptic connections due to photoreceptor cell death.
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Remodelling of Retinal on‐ and off‐bipolar cells following Experimental Retinal Detachment
Clinical & experimental ophthalmology, 2013Co-Authors: Tsutomu Sakai, Geoffrey P. Lewis, Hiroshi Tsuneoka, Steven K. FisherAbstract:Background To study the response of ON and OFF bipolar cells in Experimental Retinal Detachment. Methods Domestic cat retinas were detached for 7 days. The retinas were prepared for immunocytochemical staining with antibodies to Go alpha (α), glutamate transporter GLT-1, protein kinase C and rod opsin, which serve as markers for ON bipolar cells, OFF bipolar cells, rod bipolar cells and rod photoreceptors, respectively. Both sections and whole-mounts were labelled with antibodies to Goα and GLT-1. Results Following 7 days of Detachment, ON bipolar cell processes extended into the outer nuclear layer and had neurites extending beyond their target layer into the inner plexiform layer. In contrast, OFF bipolar cell processes were reduced in the outer plexiform layer following Detachment. Conclusion ON and OFF bipolar cells undergo significant remodelling of their processes in response to Retinal Detachment, and the ON and OFF pathways may be differentially affected. The remodelling may be due to morphological changes that have previously been shown to occur in photoreceptor synaptic terminals or as a result of loss of synaptic connections due to photoreceptor cell death.
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FGFR1, Signaling, and AP-1 Expression after Retinal Detachment: Reactive Müller and RPE Cells
2013Co-Authors: Scott F. Geller, Geoffrey P. Lewis, Steven K. FisherAbstract:PURPOSE. To identify changes in cellular signaling pathways and AP-1 expression in retina and Retinal pigmented epithelium (RPE) after Experimental Retinal Detachment (RD). METHODS. Cat and rabbit neural retinas were separated from the RPE in vivo for 5 minutes to 28 days. Tissues were removed and processed for Western blotting, immunohistochemistry, in situ hybridization, and immunoprecipitation experiments. RESULTS. An ordered sequence of events occurs after RD: (1) fibroblast growth factor (FGF) receptor 1 (FGFR1, flg) is phosphorylated in the retina within 15 minutes and dephosphorylated 2 hours after RD; (2) The extracellular signal-regulated kinase (ERK) is phosphorylated in both Müller and RPE cells within 15 minutes and remains so for several days; (3) De novo expression of c-fos mRNA coincides with increased c-Fos and c-Jun immunoreactivity in both Müller and RPE cells; (4) CRE
Kenneth A. Linberg - One of the best experts on this subject based on the ideXlab platform.
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the fate of muller s glia following Experimental Retinal Detachment nuclear migration cell division and subRetinal glial scar formation
Molecular Vision, 2010Co-Authors: Geoffrey P. Lewis, Kenneth A. Linberg, E A Chapin, Gabriel Luna, Steven K. FisherAbstract:Purpose: To study the fate of Muller’s glia following Experimental Retinal Detachment, using a “pulse/chase” paradigm of bromodeoxyuridine (BrdU) labeling for the purpose of understanding the role of Muller cell division in subRetinal scar formation. Methods: Experimental Retinal Detachments were created in pigmented rabbit eyes, and 3 days later 10 µg of BrdU was injected intravitreally. The retinas were harvested 4 h after the BrdU was administered (i.e., day 3) or on days 4, 7, and 21 post Detachment. The tissue was fixed, embedded in agarose, and sectioned at 100 µm. The sections were labeled with various combinations of probes, including anti-vimentin and anti-S100 (as markers for Muller cells), anti-BrdU, antiphosphohistone H3 (to identify mitotic cells), and the isolectin B4 (to identify macrophages and microglia). Images were captured using an Olympus Fluoview 500 confocal microscope. To aid in our understanding of how Muller cell nuclei undergo cell division, two additional procedures were used: 1) electron microscopy of normal cat and rabbit retinas and 2) a new method using 5-fluorouracil and subsequent anti-BrdU labeling to detect all Muller cell nuclei, using confocal imaging. Results: Three days after Detachment, anti-vimentin labeled all Muller cells, some of which were also labeled with antiBrdU. On day 4, many of the anti-BrdU-labeled Muller cell nuclei appeared in columns with one labeled nucleus in the inner nuclear layer and another directly sclerad to it in the outer nuclear layer. By day 7, most anti-BrdU-labeled nuclei were observed in subRetinal scars. At 3 weeks, some anti-BrdU-labeled nuclei that remained within the retina did not express vimentin or S100. Anti-phosphohistone H3-labeled (i.e., mitotic) cells, some of which were also labeled with antiBrdU, were only observed in the outer nuclear layer on day 4, and these nuclei were surrounded by an accumulation of vimentin filaments. Isolectin B4-labeled microglia and macrophages also incorporated BrdU and were observed throughout the retina and in subRetinal scars during all times of Detachment. Electron microscopy and immunofluorescence labeling of the 5-fluorouracil-injected eyes revealed the presence of a unique structural relationship between Muller cell nuclei and intermediate filament proteins. Conclusions: Following Retinal Detachment, many Muller cell nuclei initially migrate to the outer retina, undergo mitosis, and eventually reside in subRetinal glial scars, suggesting a possible link between the early division of Muller cells and the process of subRetinal gliosis. In addition, a subpopulation of anti-BrdU-labeled cells, presumably once Muller cells, appears to stop expressing well accepted Muller cell marker proteins, suggesting a potential dedifferentiation of some of these cells over time. Additionally, Muller cell nuclei may use intermediate filaments as a “track” for migration into the outer retina and later as an important component of cell division by the accumulation of vimentin filaments around the mitotic nuclei.
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Retraction and remodeling of rod spherules are early events following Experimental Retinal Detachment: an ultrastructural study using serial sections
Molecular vision, 2009Co-Authors: Kenneth A. Linberg, Geoffrey P. Lewis, Steven K. FisherAbstract:PURPOSE To describe changes induced by Retinal Detachment in the ultrastructure and organization of rod terminals and their connections with B-type horizontal cell (HC) axon terminals and rod bipolar cell (RB) dendrites. METHODS Sections from control, 3 day, 7 day, and 28 day detached feline retinas were prepared for confocal immunofluorescence, light microscopy, and electron microscopy (EM). In addition, 100 mum-thick vibratome sections were immunolabeled with markers for photoreceptor terminals, HCs, and RBs. More than 40 rod spherules were studied in 90 nm-thick serial sections by transmission EM to greater detail changes in their ultrastructure and innervation. RESULTS Following Retinal Detachment, many rod terminals retracted varying distances toward their respective cell bodies in the outer nuclear layer (ONL). In retinas detached for 1 to 4 weeks, an altered synaptic vesicle population and associated ribbons were found in all retracting terminals. Many rod somata in the distal ONL seemed to lack synaptic terminal structures altogether. In a retina detached for 1 week, EM showed that less than half of the retracted terminals remain in contact with RB dendrites. In contrast, almost every surviving spherule was contacted by neurite outgrowths from the axon terminals of the B-type HC. Although retracted spherules had several presynaptic structures similar to those in normal retina, numerous changes occurred in their overall synaptic architecture. The spherule's invagination was shallower, contained fewer postsynaptic processes, and often had "opened," allowing swollen HC processes apposing the synaptic ribbon to directly contact other processes of the outer plexiform layer (OPL) neuropil. Whereas in normal cat retina each HC "lobe" comes from a different axon terminal system, after Detachment, the opposing lateral elements can stem from the same terminal. The innervating RB dendrites that branched off stout RB dendritic trunks that extended up into the ONL were thinner than normal, unbranched, often electron dense, and lacked organelles. When present, most merely lay adjacent to retracting spherules rather than enter any synaptic invagination that might still occur. CONCLUSIONS Immunocytochemistry enabled RB and HC neurites to appear postsynaptic to retracted rod terminals. However, at the ultrastructural level, HCs seemed to more consistently retain connection with the retracted spherules than the RBs. The highly conserved architecture of the rod spherule was lost as the invagination opened and postsynaptic contacts became fewer. It would seem that the lack of RB central elements as well as the drastic alterations in the architecture of most retracted terminals would necessarily alter the physiology of this complex synapse.
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The effect of alkylphosphocholines on intraRetinal proliferation initiated by Experimental Retinal Detachment.
Investigative ophthalmology & visual science, 2007Co-Authors: Kirsten H. Eibl, Geoffrey P. Lewis, Kenneth A. Linberg, K.e. Betts, Arnd Gandorfer, Anselm Kampik, Steven K. FisherAbstract:PURPOSE. To determine the effect of alkylphosphocholines (APCs) on intraRetinal proliferation induced by Experimental Retinal Detachment in the rabbit. METHODS. Retinal Detachments were created in adult pigmented rabbits. APCs, either liposome bound (liposome, L-APC) or unbound (free, F-APC), were injected intravitreally on either day 1 or day 2 after Detachment. BrdU was injected on day 3, 4 hours before death. After fixation, retinas were triple labeled with anti-BrdU, anti-vimentin, and the isolectin B4. The number of anti-BrdU-labeled cells was counted per millimeter of retina from sections imaged by laser scanning confocal microscopy. Toxicity was examined using toluidine blue-stained sections imaged by light microscopy and by electron microscopy for ultrastructural evaluation. RESULTS. Retinal Detachment initiated proliferation of all non-neuronal cells. After intravitreal injection on day 1 or 2 after Experimental induction of Retinal Detachment, APCs significantly reduced the number of dividing cells at day 3. Liposome-bound drug given on day 2 was more effective on Miiller cell proliferation than was unbound drug. Injection of F-APC on day 1 was more effective than when given on day 2. No apparent effect was seen on Miiller cell hypertrophy as indicated by vimentin expression. In addition, no evidence of toxicity was observed in the retina at day 3 for any of the conditions. CONCLUSIONS. APCs significantly reduce the number of Miiller cells that are stimulated to divide as a result of Retinal Detachment. The preliminary results indicate no evidence of significant toxicity; however, further studies are needed. APCs have the potential to be used as part of a therapeutic approach if they can be combined with other agents that can suppress the fibrosis that is also a critical event in the pathogenesis of proliferative vitreoRetinal diseases such as proliferative vitreoretinopathy (PVR).
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immunocytochemical evidence that rod connected horizontal cell axon terminals remodel in response to Experimental Retinal Detachment in the cat
Molecular Vision, 2006Co-Authors: Kenneth A. Linberg, Geoffrey P. Lewis, Brian Matsumoto, Steven K. FisherAbstract:PURPOSE Cats have two types of horizontal cell (HC); one is axon-bearing (B-type), the other is axonless (A-type). We have previously described neurite sprouting from HCs in response to Experimental Retinal Detachment. Here we sought to determine whether one or both types elaborate these outgrowths. METHODS Sections as well as wholemounts of retinas detached for 3, 7 and 28 days together with control retinas were double or triple labeled with antibodies to the calcium binding proteins calretinin and calbindin, to the synaptic vesicle-associated membrane protein 2 (VAMP2), and to the 70 and 200 kDa subunits of the neurofilament protein. Digital immunofluorescence images were collected by both confocal and two-photon microscopy. RESULTS In control retina, both HC types label with antibodies to calretinin and calbindin D, but only the A-type also intensely labels with the neurofilament protein antibody. After 3, 7 and 28 days of Detachment, these staining patterns persist, but there is a moderate upregulation of neurofilament protein in the B-type cell. In the detached retina, HC processes sprout neurites that appear most commonly as a loose array of fine beaded processes rising from the outer plexiform layer (OPL) into the outer nuclear layer (ONL), or, especially at 28 days, as stout unbranching processes that often cross the ONL en route to the subRetinal space where some expand and arborize. Both types are strongly calretinin-positive while being somewhat less positive for antibodies to calbindin D and neurofilament protein. Moreover, they all arise from similarly labeled processes in the distal-most domain of the OPL where the narrowly stratified field of axon terminal boutons of the B-type HC normally innervates rod spherules, two to three thousand per cell. Our data indicate that the HC sprouts apparently arise specifically from the axon terminal of the B-type cell since outgrowths were never seen arising from either type of HC perikaryon or from processes identifiable as A-type dendrites. CONCLUSIONS The data described here point to the specific remodeling of the rod-connected axon terminals of the B-type cell through neurite outgrowth. Rods respond to Detachment by withdrawing synaptic terminals from the OPL while cones do not. Those HC outgrowths that terminate within the ONL appear to retain their connection with the retracted terminals. Others apparently have lost their presynaptic targets and cross the ONL in association with hypertrophied Muller cell processes.
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Cellular remodeling in mammalian retina: results from studies of Experimental Retinal Detachment.
Progress in retinal and eye research, 2005Co-Authors: Steven K. Fisher, Geoffrey P. Lewis, Kenneth A. Linberg, Mark R. VerardoAbstract:Retinal Detachment, the separation of the neural retina from the Retinal pigmented epithelium, starts a cascade of events that results in cellular changes throughout the retina. While the degeneration of the light sensitive photoreceptor outer segments is clearly an important event, there are many other cellular changes that have the potential to significantly effect the return of vision after successful reattachment. Using animal models of Detachment and reattachment we have identified many cellular changes that result in significant remodeling of the Retinal tissue. These changes range from the retraction of axons by rod photoreceptors to the growth of neurites into the subRetinal space and vitreous by horizontal and ganglion cells. Some neurite outgrowths, as in the case of rod bipolar cells, appear to be directed towards their normal presynaptic target. Horizontal cells may produce some directed neurites as well as extensive outgrowths that have no apparent target. A subset of reactive ganglion cells all fall into the latter category. Muller cells, the radial glia of the retina, undergo numerous changes ranging from proliferation to a wholesale structural reorganization as they grow into the subRetinal space (after Detachment) or vitreous after reattachment. In a few cases have we been able to identify molecular changes that correlate with the structural remodeling. Similar changes to those observed in the animal models have now been observed in human tissue samples, leading us to conclude that this research may help us understand the imperfect return of vision occurring after successful reattachment surgery. The mammalian retina clearly has a vast repertoire of cellular responses to injury, understanding these may help us improve upon current therapies or devise new therapies for blinding conditions.
Joan W. Miller - One of the best experts on this subject based on the ideXlab platform.
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Strain Difference in Photoreceptor Cell Death After Retinal Detachment in Mice
Investigative ophthalmology & visual science, 2014Co-Authors: Hidetaka Matsumoto, Joan W. Miller, Keiko Kataoka, Pavlina Tsoka, Kip M. Connor, Demetrios G. VavvasAbstract:Purpose. To evaluate the potential for mouse genetic background to effect photoreceptor cell death in response to Experimental Retinal Detachment (RD).
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Tauroursodeoxycholic Acid (TUDCA) Protects Photoreceptors from Cell Death after Experimental Retinal Detachment
PloS one, 2011Co-Authors: Dimosthenis Mantopoulos, Yusuke Murakami, Jason Comander, Aristomenis Thanos, Miin Roh, Joan W. Miller, Demetrios G. VavvasAbstract:Background Detachment of photoreceptors from the underlying Retinal pigment epithelium is seen in various Retinal disorders such as Retinal Detachment and age-related macular degeneration and leads to loss of photoreceptors and vision. Pharmacologic inhibition of photoreceptor cell death may prevent this outcome. This study tests whether systemic administration of tauroursodeoxycholic acid (TUDCA) can protect photoreceptors from cell death after Experimental Retinal Detachment in rodents. Methodology/Principal Findings Retinal Detachment was created in rats by subRetinal injection of hyaluronic acid. The animals were treated daily with vehicle or TUDCA (500 mg/kg). TUNEL staining was used to evaluate cell death. Photoreceptor loss was evaluated by measuring the relative thickness of the outer nuclear layer (ONL). Macrophage recruitment, oxidative stress, cytokine levels, and caspase levels were also quantified. Three days after Detachment, TUDCA decreased the number of TUNEL-positive cells compared to vehicle (651±68/mm2 vs. 1314±68/mm2, P = 0.001) and prevented the reduction of ONL thickness ratio (0.84±0.03 vs. 0.65±0.03, P = 0.002). Similar results were obtained after 5 days of Retinal Detachment. Macrophage recruitment and expression levels of TNF-a and MCP-1 after Retinal Detachment were not affected by TUDCA treatment, whereas increases in activity of caspases 3 and 9 as well as carbonyl-protein adducts were almost completely inhibited by TUDCA treatment. Conclusions/Significance Systemic administration of TUDCA preserved photoreceptors after Retinal Detachment, and was associated with decreased oxidative stress and caspase activity. TUDCA may be used as a novel therapeutic agent for preventing vision loss in diseases that are characterized by photoreceptor Detachment.
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Edaravone, an ROS scavenger, ameliorates photoreceptor cell death after Experimental Retinal Detachment.
Investigative ophthalmology & visual science, 2011Co-Authors: Miin Roh, Yusuke Murakami, Aristomenis Thanos, Demetrios G. Vavvas, Joan W. MillerAbstract:There are approximately 30,000 new nontraumatic Retinal Detachments (RDs) per year in the United States, and it is one of the most common causes of photoreceptor death and vision loss. Treatment options for RD are mainly surgical, such as reattachment with buckle or pneumatic reattachment with gas, and no optimal medical treatment has been found so far. Although the anatomic success rate of reattachment surgery is over 90%, the visual acuity is not always restored after successful reattachment surgery, suggesting functional impairment of the photoreceptors during RD. The separation of the neurosensory retina from the underlying Retinal pigment epithelium (RPE) reduces the photoreceptor outer segments' O2 and nutrient supply, thus causing a relative hypoxic state in the photoreceptor layer.1 These kinds of stress stimuli can lead to the generation of reactive oxygen species (ROS).2 Excessive generation of ROS and the consequent induction of oxidative stress is one of the factors that trigger cellular response to RD3 and is also a major cytotoxic factor for photoreceptor apoptosis.4,5 ROS are usually scavenged by endogenous enzymes such as ascorbate, tocopherol, glutathione, and pyridine nucleotides. However, excessive free radicals, such as those generated during ischemia, can damage the endothelial cells and neurocytes during reperfusion.6,7 Moreover, several studies in animal models of Retinal degeneration have highlighted the importance of antioxidants in the inhibition of degenerative disease.8,9 Antioxidants such as diphenylene iodonium sulfate, allopurinol, and superoxide dismutase, which are known to scavenge free radicals, have been studied for the prevention of apoptosis.10–13 However, these chemicals may not be appropriate for use in the clinic because of their toxicity and instability.14,15 Edaravone (3-methyl-1 phenyl-2-pyrazolin-5-one) is a potent hydroxyl radical scavenger that can eliminate hydrogen oxide radicals that induce lipid peroxidation. Several studies have shown that it has antioxidative and antiapoptotic effects.16–18 Moreover, it has been approved in Japan for the treatment of acute brain infarction since 2001, reducing the mortality rate when administered during the acute stage of stroke.19 The purpose of this study was to investigate the role of oxidative stress caused by ROS in a rat model of RD and whether edaravone can prevent death of photoreceptor cells by reducing the level of ROS.
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heat shock protein 70 hsp70 is critical for the photoreceptor stress response after Retinal Detachment via modulating anti apoptotic akt kinase
American Journal of Pathology, 2011Co-Authors: Maki Kayama, Yusuke Murakami, Aristomenis Thanos, Demetrios G. Vavvas, Toru Nakazawa, Yuki Morizane, Sofia Theodoropoulou, Joan W. MillerAbstract:Photoreceptor apoptosis is a major cause of vision loss in many ocular diseases. Significant progress has been made to elucidate the molecular pathways involved in this process, yet little is known about proteins counteracting these apoptotic pathways. It is established that heat shock proteins (HSPs) function as molecular helper proteins (chaperones) by preventing protein aggregation and facilitating refolding of dysfunctional proteins, critical to the survival of all organisms. Here, we investigated the role of HSP70 on photoreceptor survival after Experimental Retinal Detachment (RD) in mice and rats. We found that HSP70 was up-regulated after RD and associated with phosphorylated Akt, thereby preventing its dephosphorylation and further activation of cell death pathways. Administration of quercetin, which inhibits HSP70 and suppresses Akt phosphorylation significantly increased photoreceptor apoptosis. Similarly, RD-induced photoreceptor apoptosis was augmented in mice carrying hypomorphic mutations of the genes encoding HSP70. On the other hand, administration of geranylgeranylacetone, which induces an increase in HSP70 significantly decreased photoreceptor apoptosis after RD through prolonged activation of Akt pathway. Thus, HSP70 may be a favorable potential target to increase photoreceptor cell survival after RD.
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Caspase activation in an Experimental model of Retinal Detachment
Investigative ophthalmology & visual science, 2003Co-Authors: David N. Zacks, Virve A. Hänninen, Mina B. Pantcheva, Eric Ezra, Cynthia L. Grosskreutz, Joan W. MillerAbstract:PURPOSE. To test for apoptotic photoreceptor cell death and caspase activation as a function of time after induction of an Experimental Retinal Detachment. METHODS. Retinal Detachments were created in Brown Norway rats by injecting 10% hyaluronic acid into the subRetinal space using a transvitreous approach. Light microscopy and terminal dUTP-biotin nick end-labeling (TUNEL) was performed at 1, 3, 5, and 7 days after Detachment to assess for the morphologic features associated with apoptosis. Western blot analysis of Retinal protein extracts was performed using antibodies against caspase-3, -7, and -9 and poly-ADP ribose-polymerase (PARP) at 1, 3, and 5 days after Detachment. RESULTS. Light microscopic analysis of detached retinas showed the presence of pyknotic nuclei in the outer nuclear layer and disruption of the normal organization of the photoreceptor outer segments. TUNEL-staining was positive in the outer nuclear layer only in the detached portions of the retina. Western blot analysis confirmed the time-dependent activation of caspase-3, -7, and -9 and PARP in the detached retinas. No morphologic stigmata of apoptosis or caspase activation was detected in attached retinas. CONCLUSIONS. The apoptotic photoreceptor cell death in Experimental Retinal Detachments is associated with caspase activation.
Xiaodong Sun - One of the best experts on this subject based on the ideXlab platform.
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RNA Interference Reveals the Coregulatory Effects of Cylindromatosis on Apoptosis and Necroptosis of Photoreceptor Cells in Experimental Retinal Detachment.
The American journal of pathology, 2017Co-Authors: Kai Dong, Fenghua Wang, Linfeng Han, Jingwen Liu, Xiaodong SunAbstract:Inhibiting only cell apoptosis or necroptosis in photoreceptor cells does not protect them against death after traumatic Retinal Detachment. This study was designed to evaluate the coregulatory effects of the deubiquitinating enzyme cylindromatosis on the apoptosis and necroptosis of photoreceptor cells in Experimental Retinal Detachment. Lentivirus Cyld shRNA was generated and used to suppress cylindromatosis expression in Sprague-Dawley rats. Three weeks after injection of lentivirus Cyld shRNA, Retinal Detachment surgery was performed. Transmission electron microscopy, propidium iodide staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, electroretinography, and determination of ubiquitination and phosphorylation of receptor-interacting protein 1 were performed to detect the apoptosis and necroptosis of photoreceptor cells. Knockdown of cylindromatosis expression led to inhibition of caspase 8 activity, a decrease in the number of apoptotic photoreceptor cells, and an increase in the ubiquitination level of receptor-interacting protein 1. In addition, the number of necroptotic cells decreased and the phosphorylation level of receptor-interacting protein 1 decreased dramatically; significant protective effects of RNA interference–mediated suppression of cylindromatosis expression on electroretinogram wave were observed. Cylindromatosis coregulates the apoptosis and necroptosis of photoreceptor cells by regulating the ubiquitination of receptor-interacting protein 1 after Retinal Detachment.
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Prolyl-4-Hydroxylases Inhibitor Stabilizes HIF-1α and Increases Mitophagy to Reduce Cell Death After Experimental Retinal Detachment.
Investigative ophthalmology & visual science, 2016Co-Authors: Haiyang Liu, Hong Zhu, P. Zhang, Ning Wang, Xiaodong SunAbstract:PURPOSE This study investigated the neuroprotective effect against photoreceptor cell death using prolyl-4-hydroxylases inhibitor (PHI), an HIF-1α stabilizer, in Experimental Retinal Detachment (RD). METHODS RD was created in Brown Norway rats by subRetinal injection of 1% sodium hyaluronate. FG-4592 (a PHI, 25 mg/kg) or a vehicle was administered every 2 days with retro-orbital injection. Photoreceptor death was evaluated by TdT-dUTP terminal nick-end labeling (TUNEL) assay 3 days after RD and by the thickness of the outer nuclear layer 7 days after RD. The mitophagy-related markers Hypoxia Inducible Factor 1α (HIF-1α), BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3), autophagy-related gene 5 (Atg5), microtubule-associated protein 1 light chain 3 beta (LC3B), and FUN14 domain containing 1 (FUNDC1) were detected by Western blot and immunofluorescence. Transmission electron microscopy was used to observe ultramicro-morphological changes. Mitochondrial damage was evaluated by the measurement of reactive oxygen species (ROS) by in situ ROS detection with dihydroethidium. RESULTS The accumulation of HIF-1α and BNIP3 significantly increased after PHI treatment (P < 0.05), the pattern of Atg5 and LC3 changed, and FUNDC1 and LC3 were colocated. More autophagic vacuoles engulfing mitochondria were observed in transmission electron microscopy sections after PHI treatment when compared with the control. ROS significantly decreased in the PHI-treatment group (P < 0.05). This resulted in reduced TUNEL-positive photoreceptors 3 days after RD and an increased thickness of the outer nuclear layer 7 days after RD (P < 0.05). CONCLUSIONS HIF-1α stabilization as a result of PHI treatment, along with the enhancement of mitophagy, could provide protection against photoreceptor injury following RD, which might be mediated by excessive ROS generation.
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Reactivation of the PI3K/Akt Signaling Pathway by the Bisperoxovanadium Compound bpV(pic) Attenuates Photoreceptor Apoptosis in Experimental Retinal Detachment.
Investigative ophthalmology & visual science, 2015Co-Authors: Dan Mao, Xiaodong SunAbstract:PURPOSE Phosphatase and tensin homology deleted on chromosome 10 (PTEN) is crucial in neuronal apoptosis. This study evaluated the role of PTEN in photoreceptor cell apoptosis caused by Retinal Detachment (RD). METHODS A rat model of RD was established, and PTEN expression changes were detected at different time points by Western blotting and immunofluorescence. Some of the rats were given subRetinal injections of bisperoxovanadium compound (bpV[pic]) after RD. We documented the expression and distribution of phospho-Akt (p-Akt) and B-cell lymphoma 2 (Bcl-2) in the retina by Western blot analysis and immunofluorescence. Levels of phosph-phosphoinositide-dependent kinase 1 (p-PDK1), phospho-Bcl-2 death promotor (p-BAD), cytosolic cytochrome c (Cyt c), and cleaved Caspase-3 were detected by Western blotting. We measured phosphatidylinositol 3,4,5-triphosphate (PIP3) by ELISA. Apoptosis of photoreceptors was detected using the TUNEL assay. The thickness of the outer nuclear layer (ONL) also was recorded. RESULTS The expression of PTEN gradually increased after RD, peaking at 3 days and then decreasing to normal by 7 days after RD. SubRetinal injection of bpV(pic) effectively reduced the apoptosis of photoreceptors and preserved the Retinal thickness of the ONL after RD. Compared to vehicle-treated RD groups, levels of p-Akt and p-PDK1 were significantly upregulated in bpV-treated RD groups. In addition, bpV treatment increased the levels of p-BAD and Bcl-2, and decreased the expression levels of cytosolic Cyt c and cleaved caspase-3 after RD. CONCLUSIONS Phosphatase and tensin homology deleted on chromosome 10 (PTEN) participates in the apoptosis of photoreceptors after RD. Blocking PTEN may reactivate the PI3K/Akt pathway and attenuate photoreceptor apoptosis by suppressing the mitochondrial pathway.
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reactivation of the pi3k akt signaling pathway by the bisperoxovanadium compound bpv pic attenuates photoreceptor apoptosis in Experimental Retinal Detachment
Investigative Ophthalmology & Visual Science, 2015Co-Authors: Dan Mao, Xiaodong SunAbstract:PURPOSE Phosphatase and tensin homology deleted on chromosome 10 (PTEN) is crucial in neuronal apoptosis. This study evaluated the role of PTEN in photoreceptor cell apoptosis caused by Retinal Detachment (RD). METHODS A rat model of RD was established, and PTEN expression changes were detected at different time points by Western blotting and immunofluorescence. Some of the rats were given subRetinal injections of bisperoxovanadium compound (bpV[pic]) after RD. We documented the expression and distribution of phospho-Akt (p-Akt) and B-cell lymphoma 2 (Bcl-2) in the retina by Western blot analysis and immunofluorescence. Levels of phosph-phosphoinositide-dependent kinase 1 (p-PDK1), phospho-Bcl-2 death promotor (p-BAD), cytosolic cytochrome c (Cyt c), and cleaved Caspase-3 were detected by Western blotting. We measured phosphatidylinositol 3,4,5-triphosphate (PIP3) by ELISA. Apoptosis of photoreceptors was detected using the TUNEL assay. The thickness of the outer nuclear layer (ONL) also was recorded. RESULTS The expression of PTEN gradually increased after RD, peaking at 3 days and then decreasing to normal by 7 days after RD. SubRetinal injection of bpV(pic) effectively reduced the apoptosis of photoreceptors and preserved the Retinal thickness of the ONL after RD. Compared to vehicle-treated RD groups, levels of p-Akt and p-PDK1 were significantly upregulated in bpV-treated RD groups. In addition, bpV treatment increased the levels of p-BAD and Bcl-2, and decreased the expression levels of cytosolic Cyt c and cleaved caspase-3 after RD. CONCLUSIONS Phosphatase and tensin homology deleted on chromosome 10 (PTEN) participates in the apoptosis of photoreceptors after RD. Blocking PTEN may reactivate the PI3K/Akt pathway and attenuate photoreceptor apoptosis by suppressing the mitochondrial pathway.
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Inhibition of TRB3 Protects Photoreceptors against Endoplasmic Reticulum Stress-Induced Apoptosis after Experimental Retinal Detachment
Current eye research, 2015Co-Authors: Quan Yan, Fenghua Wang, Xi Zhang, Hong Zhu, Wenqiu Wang, Jingyang Feng, Xiang Shi, Yanping Zhou, Xiaodong SunAbstract:AbstractPurpose: To investigate the expression of tribbles homologue 3 (TRB3) and its regulation on endoplasmic reticulum stress (ERS)-induced photoreceptor apoptosis after Retinal Detachment (RD) using a rat model.Methods: RD animal model was created in Wistar rats by subRetinal injection of 1% sodium hyaluronate. At various time points after RD, expression of TRB3 was detected by quantitative real-time PCR and Western blotting. TRB3 protein distribution in retina was evaluated by immunohistochemistry. RNA interference was used to inhibit TRB3 expression and subRetinal injection of lentivirus TRB3 shRNA (LV-TRB3-sh) was performed. The rats were then randomly divided into four groups: normal control group, RD group, vehicle + RD group and LV-TRB3-sh + RD group. The mRNA and protein level of TRB3 as well as Caspase-12 were detected. TdT-mediated fluorescein-16-dUTP nick-end labeling (TUNEL) assay was used to detect the apoptosis of Retinal cells. Retinal outer nuclear layer (ONL) thickness was measured to ...
