| 1. |
- Ahuja-Jensen, Poonam, et al.
(författare)
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Low glutathione peroxidase in rdl mouse retina increases oxidative stress and proteases
- 2007
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Ingår i: NeuroReport. - 1473-558X. ; 18:8, s. 797-801
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Tidskriftsartikel (refereegranskat)abstract
- Malondialdehyde, reduced glutathione, glutathione peroxidase, glutathione reductase and cysteine protease cathepsins at postnatal (PN) days 2, 7, 14, 21 and 28 in controls (wt) and the retinal degeneration 1 (rd1) mouse model for retinitis pigmentosa retinas were measured to determine oxidative stress. In PN28 wt and PN2 rd1 retinas, elevated malondialdehyde and low glutathione peroxidase activity indicate higher oxidative load, despite higher reduced glutathione in PN2 rd1 retinas. This is due to physiological exposure to light and retinal vascular/neural restructuring, respectively. Compared with wt retinas, relatively high malondialdehyde at PN2 and cathepsin levels at PN14, 21 and 28 in rd1 retinas indicate that cells of the residual inner retina also contribute to the oxidative stress and retinal degeneration.
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| 2. |
- Ahuja, Poonam, et al.
(författare)
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Decreased glutathione transferase levels in rd1/rd1 mouse retina: Replenishment protects photoreceptors in retinal explants.
- 2005
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Ingår i: Neuroscience. - : Elsevier BV. - 1873-7544 .- 0306-4522. ; 131:4, s. 935-943
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Tidskriftsartikel (refereegranskat)abstract
- Currently much attention is focused on glutathione S transferase (GST)-induced suppression of apoptosis. The objective of our studies was therefore to see if GST isoenzymes rescue photoreceptors in retinal explants from rd1/rd1 mice, in which photoreceptors degenerate rapidly. Eyes from C3H rd1/rd1 and +/+ mice were collected at various time points between postnatal day (PN) 2 and PN28. Localization and content of alpha-GST and mu-GST was investigated by immunofluorescence and semi-quantitative Western blot analysis, respectively. In addition, PN2 and PN7 retinal explants were cultured till PN28, during which they were treated with 10 ng/ml alpha-GST or mu-GST. The spatiotemporal expression of both GST isoforms was closely similar: early presence in ganglion cell layer after which staining became restricted to Muller cells (particularly in the endfeet) and horizontal cell fibers in both rd1/rd1 and +/+. Doublets of alpha-GST and mu-GST were detected by Western blot analysis. Densitometry of these bands indicated steady reduction of alpha-GST content in rd1/rd1 retina starting from the second postnatal week. When alpha-GST and mu-GST were added exogenously to rd1/rd1 explants, photoreceptor rescue was produced that was more prominent in PN2 than in PN7 explants and more effective by alpha-GST than mu-GST. We propose that alpha-GST neuroprotection is mediated by reduction of tissue oxidative stress.
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| 3. |
- Ahuja, Sat pal, et al.
(författare)
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Glutathione S-transferase µ(GST) modifies activities of proteases and levels of cystatin C secreted by mouse retinal explants
- 2004
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Ingår i: Investigative Ophthalmology & Visual Science. - 1552-5783. ; 45, s. 352-352
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Konferensbidrag (refereegranskat)abstract
- Purpose: In one form of human autosomal recessive retinitis pigmentosa and in retinal degeneration (rd1) mouse, mutation occurs in the genes encoding ß subunit of rod photoreceptor cGMP phosphodiesterase. Therefore, rd1 mutant mouse is an appropriate model for human inherited retinal degeneration studies. Retinal explants are successfully cultured in serum free chemically defined R16 medium to evaluate effects of various rescue factors and retinal conditioned medium (RCM) for secreted molecules like proteases and their inhibitors. Cysteine protease inhibitor cystatin C has recently been identified in rodent neuroretina and RPE. RCM of explants treated with GST were analyzed for proteases and cystatin C to explain, in part, mode of action of GST in protection of degenerating retina. Methods: Postnatal day 2 (PN2) and PN7 control (wt) and rd1 were cultured with (10 ng / ml GST) and without GST in R16 medium, respectively, for 26 and 21 days in vitro (div). Retinal extracts (RE) and RCM were analyzed by fluorometry using casein green fluorescent labeled with BODIPY–FL (Molecular Probes) for total proteases; Z–Phe–Arg–NMec or Z–Arg–Arg–NMec for cysteine proteases and by ELISA for cystatin C, respectively, for levels and secretion of proteases and cystatin C. The protein content of RE was measured. Results: Protein content (µg) of RE from wt and rd1 retinal extracts respectively increased and decreased with age. Cystatin C (ng/ml RCM) content in wt and rd1 RE increased with age (was always higher in wt) up to PN14 and then decreased but was higher than that at PN2. Progressive secretion of cystatin C by PN2 explants was lower than that by PN7 explants; and that by rd1 PN2 and PN7 explants was initially lower up to in vitro age of PN19 and subsequently it was higher than that by wt explants. Secretion of total cystatin C by PN2 and PN7 wt and rd1 explants was similar and was increased by GST. During initial stage of culture total protease activity ({Delta} F / 100 µl RCM) in RCM of rd1 PN2 and PN7 explants was higher and was decreased in GST treated explants. Conclusions: Cystatin C content and secretion by wt RE is always higher and that of proteases is lower than that of rd1. Treatment with GST increases content of cystatin C and consequently decreases that of proteases especially cysteine proteases.
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| 4. |
- Ahuja, Sat pal, et al.
(författare)
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Physiopathology of retinal degeneration in rd1 mouse model of retinitis pigmentosa : TGF-Β1, proteinases and oxidative stress mechanisms
- 2009
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Ingår i: Retinal Degeneration: Causes, Diagnosis and Treatment. - 9781607410072 ; , s. 1-41
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Bokkapitel (refereegranskat)abstract
- The rd1 (retinal degeneration) mouse retina shows degeneration homologous to a form of retinitis pigmentosa with a rapid loss of rod photoreceptors and deficiency of retinal blood vessels. Due to Pde6brd1 gene mutation, β subunit of phosphodiesterase (PDE) of rd1 retina has an inactive PDE which elevates cGMP and Ca2+ ions level. In vitro retinal explants provide a system close to the in vivo situation, so both approaches were used to compare the status of oxidative stress, transforming growth factor-β1 (TGF-β1), sialylation, galactosylation of proteoglycans, and different proteinases-endogenous inhibitors systems participating in extracellular matrix (ECM) remodeling/degeneration and programmed cell death (PCD)/apoptosis in wt and rd1 mouse retinas. Proteins and desialylated sulfated glucosaminoglycan parts of proteoglycans in ECM of rd1 retina were, respectively, decreased and increased due to enhanced activities of proteinases. Desialylation increases the susceptibility of cells to phoagocytosis/apoptosis, decreased neurogenesis and faulty guidance cues for synaptogenesis. In vivo activities of total proteinases, matrix metalloproteinase-9 (MMP-9) and cathepsin B were increased in rd1 retina on postnatal day 14 (PN14), -21 and -28, due to relatively lower levels of tissue inhibitor of MMPs (TIMP-1) and cystatin C, respectively. This corresponded with increased in vitro secretion of these proteinases by rd1 retina. Cells including end-feet of Mueller cells in degenerating rd1 retina showed intense immunolabeling for MMP-9, MMP-2/TIMP-1, TIMP-2 and cathepsin B/cystatin C, and proteinases pool was increased by Mueller cells. Intense immunolabeling of ganglion cell (RGC) layer for cathepsin B and of inner-plexiform layer of both PN2/PN7 rd1 and wt retinas indicated importance of cathepsin B in synaptogenesis and PCD of RGC. Increased levels of TGF-β1 in vitro transiently increased the secretion of MMPs and cathepsins activities by wt explants which activate TGF-β1 and remodel the ECM for angiogenesis and ontogenetic PCD. Whereas, lower level of TGF-β1 and persistently higher activities of MMPs and cathepsins in rd1 retinas and conditioned medium, suggested that proteinases degraded TGF-β1 and ECM and caused retinal degeneration. Lower activities of glutathione-S-transferase and glutathione-peroxidase in rd1 retina contribute to oxidative stress which damages membranes and increased the expression, release/secretion of proteinases relative to their endogenous inhibitors. Participation of oxidative stress in rd1 retinal degeneration was further confirmed from the partial protection of rd1 photoreceptors by in vitro and/or in vivo supplementation with glutathione-S-transferase or a combination of antioxidants namely lutein, zeaxanthin, α-lipoic acid and reduced-L-glutathione. Treatment with combination(s) of broad spectrum proteinase inhibitor(s) and antioxidants needs investigation.
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| 5. |
- Ahuja, Sat pal, et al.
(författare)
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rd1 Mouse retina shows an imbalance in the activity of cysteine protease cathepsins and their endogenous inhibitor cystatin C.
- 2008
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 49:3, s. 1089-1096
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To compare in vivo levels, spatial localization, and in vitro secretion of cysteine protease cathepsins and cystatin C (cysC) in the retinal degeneration 1 (rd1) mouse model of retinitis pigmentosa and control (wt) mouse retinas. METHODS: The spatial localization, protein contents, cysC levels and cathepsin-B, -S, and -L activities in wt and rd1 retinas at postnatal (PN) days 2, 7, 14, 21, and 28 were analyzed by immunostaining, spectrophotometry, ELISA, and fluorescence spectrophotometry. The in vitro secretion of cysC and cysteine proteases by PN7 retinal explants into the conditioned medium (RCM) was quantified. RESULTS: The pigment epithelium, photoreceptors, and inner retinal and ganglion cell layers of both wt and rd1 retinas showed cysC and cathepsin-B labeling. CysC immunostaining was extensive in the optic nerve head fibers. The rd1 explants secreted higher amounts of cysteine protease into the RCM. The protein content in wt and rd1 retinal extracts increased up to PN14, then decreased in rd1 but not in wt. In rd1 extracts at PN14 to -28, cathepsin activity was higher and increased with age, but the cysC level was higher and constant. The ratios of cathepsin activity to cysC (cathepsin-L at PN2 and total, -B, and -L at PN14 to -28) were higher in rd1 extracts. CONCLUSIONS: Similar localization of both cathepsin-B and cysC in wt and rd1 retinas along with lower proteins and higher cathepsin activity in rd1 retinal extracts and RCM are consistent with their localization in extracellular matrix and a role in physiopathologic remodeling in wt and rd1 retinas.
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| 6. |
- Ahuja, Sat pal, et al.
(författare)
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rd1 Mouse Retina Shows Imbalance in Cellular Distribution and Levels of TIMP-1/MMP-9, TIMP-2/MMP-2 and Sulfated Glycosaminoglycans.
- 2006
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Ingår i: Ophthalmic Research. - : S. Karger AG. - 1423-0259 .- 0030-3747. ; 38:3, s. 125-136
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Tidskriftsartikel (refereegranskat)abstract
- Background: The rd1 mouse retina displays fast degeneration of photoreceptors resulting in a depletion of almost all rod photoreceptors by postnatal day 21 (PN21). To evaluate the role of proteinases in the pathophysiology of this animal model of retinitis pigmentosa, C3H rd1 and congenic wild-type (wt) mice retinas were analyzed. Material and Methods: The cellular localization and levels of proteins, matrix metalloproteinases (MMPs), their endogenous inhibitors (TIMPs), total sulfated glycosaminoglycans (sGAG) and nature of saccharides in roll and wt retinal extracts were compared. Results: MMP-2/TIMP-2 and MMP-9/TIMP-1 were predominantly localized in the interphotoreceptor matrix (IPM) of both genotypes, but MMP-2/TIMP-2 also appeared in the Muller cell fibers of rd1 retina. In rd1 retinal extracts the levels of total proteins were lower and those of active MMP-9, MMP-2, TIMP-1 and total sGAG were higher than those of wt extracts. Despite an increase in TIMP-1, active MMP-9/MMP-2 were disproportionately elevated in rd1 compared to wt retina. With increasing age, MMPs in wt retinas were decreased but were increased in rd1. The sialylation of proteoglycans in PN2 and PN7 rd1 retinas was lower, and galactosylation was higher than that in wt retinas. Conclusions: MMP-9/ MMP-2 and TIMP-1/TIMP-2 are associated with IPM, possibly after secretion by retinal pigmented epithelial cells. In degenerating rd1 retina, MMP-2/TIMP-2 are associated with the Muller cell fibers, which apparently play a central role in modifying the balance between MMPs and TIMPs. Elevated sGAG and proteolysis due to an imbalance in the levels of TIMPs and active MMP-9/MMP-2 in rd1 retina possibly contribute to retinal degeneration in the rd1 mouse.
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| 7. |
- Ahuja, Sat pal, et al.
(författare)
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Serum-free retinal explant culture system and comparative rescue effects of LEDGF, GST, CNTF, BDNF, NGF, bFGF and antioxidants in the rd1 mouse model of retinitis pigmentosa
- 2009
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Ingår i: Retinal Degeneration: Causes, Diagnosis and Treatment. - 9781607410072 ; , s. 263-299
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Bokkapitel (refereegranskat)abstract
- Retinitis pigmentosa is a group of inherited retinal degenerative diseases characterized by the loss of photoreceptors and vision for which no effective treatment is available. Several animal models of retinitis pigmentosa are used to elucidate its pathogenesis and to devise therapies. The retinal degeneration (rd1) mouse is one such animal model in which rod-specific phosphodiesterase (PDE) is inactive due to a mutation in the β-subunit of the Pde gene (Pde6brd1). This mutation leads to increased levels of retinal cyclic guanosine monophosphate (cGMP) and Ca2+ ions and eventually retinal degeneration by increased oxidative stress, activation of poly-(ADP-ribose)-polymerase-1 and proteinases including calpains and caspases. However, diverse overlapping mechanism(s) of cell death have been described. An in vitro retinal explant culture system was developed, as results of studies involving isolated retinal cells and the in vivo models are difficult to interpret. Neonatal and postnatal retinas of wild type (wt) and rd1 mice were cultured successfully in a serum-free medium containing bovine serum albumin. The cultured wt and rd1 retinas respectively developed and degenerated in ways similar to the age-matched in vivo retinas of the two genotypes. This was confirmed from the similar retinal lamination pattern, expression and immunohistochemical localization of opsin, rhodopsin, arrestin, interphotoreceptor retinol-binding protein and calcium-binding protein markers, namely, calbindin, parvalbumin and calretinin in age-matched in vivo and cultured retinas of both genotypes. Horizontal cell fibers and Mueller cells of in vivo retina showed the presence of α-and μ-glutathione-S-transferases (GST). In rd1 mouse retina, GST and glutathione peroxidase (GPx) levels were lower than those in wt and suggested an oxidative stress. The photoreceptor rescue effects of lens epithelium-derived growth factor (LEDGF), α-GST, and μ-GST; and ciliary neurotrophic factor (CNTF), brain-derived growth factor (BDNF), nerve growth factor (NGF), basic fibroblast growth factor (bFGF); and antioxidants (lutein, zeaxanthin, glutathione and α-lipoic acid) were compared after supplementation in a serum-free retina organ culture system. The above combination of antioxidants rescued the rd1 photoreceptors both under in vitro and in vivo conditions. The maximum photoreceptors rescue was by CNTF + BDNF, whereas that by NGF + bFGF was intermediate. CNTF, BDNF, NGF, and bFGF individually rescued the photoreceptors, but their effect was less than those of their combinations. LEDGF and GST supplementation in vitro delayed rod photoreceptor degeneration in postnatal day-2 (PN2) and PN7 rd1 explants cultured in vitro for 26 and 21 days, respectively, possibly by reversing the oxidative stress. The latter was confirmed from the lower levels of GPx and from the rescue of rd1 photoreceptors by in vitro and in vivo supplementation with LEDGF or the combination of antioxidants. Individual antioxidants were ineffective in rescuing the photoreceptors under in vivo and in vitro conditions.
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| 8. |
- Archer, SN, et al.
(författare)
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Absence of phosphoglucose isomerase-1 in retinal photoreceptor, pigment epithelium and Muller cells
- 2004
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Ingår i: European Journal of Neuroscience. - 1460-9568. ; 19:11, s. 2923-2930
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Tidskriftsartikel (refereegranskat)abstract
- Macroarray analysis was used to compare equal amounts of cDNA from wild-type and rd/rd (retinal degeneration) mice, collected at P90 when photoreceptor degeneration is virtually complete. A stronger signal for the glycolytic enzyme phosphoglucose isomerase (Gpi1) was observed in the rd/rd sample. Extracellularly, Gpi1 may act as a cytokine, independently described as neuroleukin and autocrine motility factor. Retinal Gpi1 expression was investigated by Northern and Western blot analysis and immunohistochemistry. Double-labelling was performed with antibodies against Gpi1 and calbindin-D, glutamine synthetase, RPE65, calretinin and ultraviolet opsin in order to provide positive cell type identification. Northern and Western blots showed double expression levels per microgram of RNA and protein, respectively, in the rd/rd retina compared with wild-type. However, the total amount of Gpi1 protein per retina was indistinguishable. Gpi1 immunoreactivity was found in ganglion, amacrine, horizontal and bipolar cells, but not in rods, cones, pigment epithelium and Muller cells. This distribution explains why the absolute amounts of Gpi1 protein were not appreciably different between wild-type and the rd/rd phenotype, where rods and cones are absent, whilst the relative contribution of Gpi1 to the total protein and RNA pools differed. Some extracellular immunoreactivity was observed in the photoreceptor matrix around cones in freshly fixed tissue only, which could possibly reflect a role as a cytokine. We propose that glycolysis in Gpi1-negative cells proceeds entirely through the pentose phosphate pathway, creating NADPH at the cost of organic carbon. We hypothesize that the unique metabolic needs of photoreceptors justify this trade-off.
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| 9. |
- Azadi, Seifollah, et al.
(författare)
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CNTF plus BDNF treatment and neuroprotective pathways in the rd1 mouse retina
- 2007
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Ingår i: Brain Research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1129:1, s. 116-129
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Tidskriftsartikel (refereegranskat)abstract
- The rd1 mouse is a relevant model for studying the mechanisms of photoreceptor degeneration in retinitis pigmentosa. Treatment with ciliary neurotrophic factor (CNTF) in combination with brain derived neurotrophic factor (BDNF) is known to rescue photoreceptors in cultured rd1 retinal explants. To shed light on the underlying mechanisms, we studied the effects of 9 days (starting at postnatal day 2) in vitro CNTF+BDNF treatment on the endogenous production of CNTF, BDNF, fibroblast growth factor 2 (FGF2), or the activation of extracellular signal-regulated kinase (ERK), Akt and CAMP-response-element-binding protein (CREB) in retinal explants. In rd1 explants, CNTF+BDNF decreased the number of TUNEL-positive photoreceptors. The treatment also increased endogenous rd1 levels of CNTF and BDNF, but lowered the level of FGF2 expression in rd1 explants. When wild-type explants were treated, endogenous CNTF was similarly increased, while BDNF and FGF2 levels remained unaffected. In addition, treatment of rd1 retinas strongly increased the phosphorylation of ERK, Akt and CREB. In treated wild-type explants, the same parameters were either unchanged (ERK) or decreased (Akt and CREB). The results suggest a role for Akt, ERK and CREB in conveying the neuroprotective effect of CNTF+BDNF treatment in rd1 retinal explants. (c) 2006 Elsevier B.V. All rights reserved.
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| 10. |
- Azadi, Seifollah, et al.
(författare)
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Thyroid-beta2 and the retinoid RAR-alpha, RXR-gamma and ROR-beta2 receptor mRNAs; expression profiles in mouse retina, retinal explants and neocortex.
- 2002
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Ingår i: NeuroReport. - 1473-558X. ; 13:6, s. 745-750
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Tidskriftsartikel (refereegranskat)abstract
- In neonatal retinal explants cultured long-term green cones are missing. Recently it was reported that thyroid hormone beta2 receptors (TR-beta2) are essential for these green cones to differentiate. Therefore transcript level of these receptors was investigated in our mouse retinal explants. However, thyroid receptors function as heterodimers with retinoid receptors (RR); so the fate of selected RRs was similarly analyzed using semi-quantitative RT-PCR. Loss of TR-beta2 and RR (RXR-gamma and ROR-beta2) mRNAs was observed after culturing the neonatal retina for 12 days. This indicates that these proteins are involved in determination of green cone identity. In addition, levels of the selected RR transcripts are differentially affected by short- or long-term culture. In the latter case an attached retinal pigment epithelium seems to play a protective role. Furthermore, divergent diurnal peaks of RR mRNAs are present in young as well as aged mouse retina and neocortex. This data might be relevant in the context of human ageing disorders.
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| 11. |
- Azadi, Seifollah, et al.
(författare)
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Up-regulation and increased phosphorylation of protein kinase C (PKC) delta, mu and theta in the degenerating rd1 mouse retina.
- 2006
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Ingår i: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431. ; 31:4, s. 759-773
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Tidskriftsartikel (refereegranskat)abstract
- The rd1 mouse serves as a model for inherited photoreceptor degeneration: retinitis pigmentosa. Microarray techniques were employed to compare the transcriptomes of rd1 and congenic wild-type retinas at postnatal day 11, when degenerative processes have started but most photoreceptors are still present. Of the several genes that were differentially expressed, focus was put on those associated with the protein kinase C (PKC) signaling pathway, in particular PKCδ, μ and θ. Microarray identified these as being up-regulated in the rd1 retina, which was confirmed by QRT-PCR. Western blotting and immunostaining, using antibodies against either total or phosphorylated variants of the PKC isoforms, revealed increased expression and phosphorylation of PKCδ, μ and θ in the rd1 retina at the protein level as well. Our results suggest that these PKC isoforms are involved in rd1 degeneration.
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| 12. |
- Borg, Bertil, et al.
(författare)
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The Parapineal Organ of Teleosts
- 1983
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Ingår i: Acta Zoologica. - : Wiley. - 0001-7272 .- 1463-6395. ; 64:4, s. 211-218
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Tidskriftsartikel (refereegranskat)abstract
- A parapineal organ was found to be present in 21 teleost fishes belonging to 20 different families, but was absent in poecilids and cyprinodontids. The parapineal organ was situated on the left side of the brain and sent a nerve tract to the left habenular nucleus, except in Gadus, where a “parapineal organ” appeared to send a nerve tract into the pineal stalk. The parapineal organ of adult Gasterosteus consisted of glial elements and parapinealocytes. The latter were small neurons which sent off the unmyelinated axons that formed the parapineal tract. A single photoreceptor cell was found in a stickleback parapineal organ. 1983 The Royal Swedish Academy of Sciences
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| 13. |
- Bujakowska, Kinga, et al.
(författare)
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Study of Gene-Targeted Mouse Models of Splicing Factor Gene Prpf31 Implicated in Human Autosomal Dominant Retinitis Pigmentosa (RP)
- 2009
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 50:12, s. 5927-5933
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. Pre-mRNA processing factor 31 (PRPF31) is a ubiquitous protein needed for the assembly of the pre-mRNA splicing machinery. It has been shown that mutations in this gene cause autosomal dominant retinitis pigmentosa 11 (RP11), which is characterized by rod-cell degeneration. Interestingly, mutations in this ubiquitously expressed gene do not lead to phenotypes other than retinal malfunction. Furthermore, the dominant inheritance pattern has shown incomplete penetrance, which poses interesting questions about the disease mechanism of RP11. METHODS. To characterize PRPF31 function in the rod cells, two animal models have been generated. One was a heterozygous knock-in mouse (Prpf31(A216P/+)) carrying a point mutation p.A216P, which has previously been identified in RP11 patients. The second was a heterozygous knockout mouse (Prpf31(+/-)). Retinal degeneration in RP11 mouse models was monitored by electroretinography and histology. RESULTS. Generation of the mouse models is presented, as are results of ERGs and retinal morphology. No degenerative phenotype on fundus examination was found in Prpf31(A216P/+) and Prpf31(+/-) mice. Prpf31(A216P/A216P) and Prpf31(-/-) genotypes were embryonic lethal. CONCLUSIONS. The results imply that Prpf31 is necessary for survival, and there is no compensation mechanism in mouse for the lack of this splicing factor. The authors suggest that p.A216P mutation in Prpf31 does not exert a dominant negative effect and that one Prpf31 wild-type allele is sufficient for maintenance of the healthy retina in mice.
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| 14. |
- Ekström, Peter, et al.
(författare)
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Distribution of 5‐hydroxytryptamine (serotonin) in the brain of the teleost Gasterosteus aculeatus L.
- 1984
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967. ; 226:3, s. 307-320
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of serotoninergic neurons in the brain of the three‐spined stickleback was demonstrated with the indirect peroxidase‐antiperoxidase (PAP) immunohistochemical method with antibodies against serotonin. Serotoninergic perikarya were demonstrated in the brainstem reticular formation (nucleus raphe dorsalis, nucleus raphe medialis, and nucleus tegmenti dorsalis lateralis) and in the periventricular ventral thalamus and hypothalamus (nucleus ventromedialis thalami, nucleus posterioris periventricularis, nucleus recessus lateralis, and nucleus recessus posterioris). After pharmacological pretreatment of the animals with a monoamine oxidase inhibitor, serotoninergic perikarya were also visualized in area praetectalis and in the medial brainstem, caudal to nucleus raphe medialis. Whereas the cell groups of the brainstem give rise to both ascending and descending pathways, it was not possible to analyze the distribution of efferent projections from the diencephalic cell groups. Distribution of serotoninergic axons showed marked regional differences. Only scattered varicose fibers were demonstrated in the cerebellum, the facial lobes, and the lateral line lobes. In the mesencephalon, the dorsal periventricular tegmentum and the central gray receive only small numbers of serotoninergic axons, while torus semicircularis and the visual layers of tectum opticum are profusely innervated. In the diencephalon, the hypothalamus and ventral thalamus generally display the highest density of serotoninergic axons. Exceptions are found in nucleus glomerulosus and the ventromedial portion of lobus inferioris, where densities are low. In the telencephalon, the density of serotoninergic axons is very high in area dorsalis pars medialis and pars lateralis dorsalis, but low in area dorsalis pars dorsalis and pars lateralis ventralis, and intermediate in area ventralis.
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| 15. |
- Ekström, Peter, et al.
(författare)
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Distribution of noradrenaline in the brain of the teleost Gasterosteus aculeatus L. : An immunohistochemical analysis
- 1986
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967. ; 254:3, s. 297-313
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of noradrenergic neurons in the brain of the threespined stickleback was demonstrated with the indirect peroxidase‐antiperoxidase (PAP) immunohistochemical method with antibodies against a noradrenaline‐bovine serum albumin conjugate. Noradrenergic neuronal somata were exclusively located in the isthmal area of the brain stem and in the lower medulla. Noradrenergic varicose axons innervate the reticular formation, motor nuclei, and interpeduncular nucleus of the brain stem, the hypothalamus and habenular nuclei, various parts of the area dorsalis telencephali (forebrain pallium), and the olfactory bulbs. Scattered noradrenergic axons were observed in the optic tectum and in various parts of the cerebellum. It is concluded that the isthmal cell group of the stickleback is, on topological and cytoarchitectonic grounds, equivalent to the ventral portion of the locus coeruleus/subcoeruleus area of amniotes, but that its efferent connections display features characteristic both of those originating in the locus coeruleus, and in the lateral tegmental cell groups of mammals.
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| 16. |
- Ekström, Peter, et al.
(författare)
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Ontogenetic development of serotoninergic neurons in the brain of a teleost, the three-spined stickleback. An immunohistochemical analysis
- 1985
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Ingår i: Developmental Brain Research. - : Elsevier BV. - 0165-3806. ; 17:1-2, s. 209-224
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Tidskriftsartikel (refereegranskat)abstract
- The ontogenetic development of serotoninergic neurons in the brain of the stickleback was investigated with the indirect immunocytochemical peroxidase-antiperoxidase technique, using a specific antibody to serotonin (5-hydroxytryptamine, 5-HT). Formation of neuronal populations takes place during embryonic development. By 80 h after fertilization, the first 5-HT perikarya have appeared in the ventricular zone of the hypothalamus (nucleus recessus lateralis) and the raphe region. At 108 h the first 5-HT perikarya can be observed in area praetectalis. At 118 h a transient group of 5-HT neurons appears rostral to the nucleus recessus lateralis, and at this same age the first 5-HT perikarya may be visualized in nucleus recessus posterioris. A group of 5-HT neurons appears in the dorsolateral tegmentum at 166 h (one day after hatching, which occurs at 120-144 h after fertilization). Differentiation of the neuronal populations, in terms of migration and formation of subdivisions, starts between 80 h and 94 h, and seems to be completed between 1 and 5 days after hatching. Raphe nuclei form an anterior group comprising nuclei raphe dorsalis, raphe medialis and a ventrolateral group, and a posterior group comprising a nucleus raphe pallidus/obscurus complex, a lateral nucleus reticularis paragigantocellularis and a ventromedial nucleus raphe magnus. The posterior and ventral raphe nuclei, which are well developed at the time of hatching, have not been visualized in the adult stickleback. While formation of 5-HT neuronal systems, as well as their primary efferent pathways, takes place during early ontogenetic development, the establishment of terminal areas and their subsequent differentiation apparently takes place during later ontogenetic stages. Most presumptive target areas are penetrated by 5-HT axons at hatching, although terminal formation does not seem to start until later. A considerable number of 5-HT neuronal groups present in the embryonic and newly hatched stickleback have not been visualized in the adult stickleback. This may be due to selective cell death, changes in transmitter phenotype or maturation of axonal transport processes during development.
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| 17. |
- Ekström, P., et al.
(författare)
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Ontogenetic development of the pineal organ, parapineal organ, and retina of the three-spined stickleback, Gasterosteus aculeatus L. (Teleostei) - Development of photoreceptors
- 1983
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Ingår i: Cell and Tissue Research. - 0302-766X. ; 233:3, s. 593-609
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Tidskriftsartikel (refereegranskat)abstract
- The ontogenetic developments of the pineal organ, parapineal organ, and retina were studied by the use of light and electron microscopy in embryos and fry of the teleost, Gasterosteus aculeatus, from 60 to 168 h after fertilization. Sixty to 66 h after fertilization, the primordium of the pineal complex is discernible in the diencephalic roofplate; the parapineal anlage is located rostral to the pineal anlage. Photoreceptor cells endowed with outer segments are present in the embryonic pineal organ already after 72 h, whereas outer segments of retinal photoreceptors could not be demonstrated before 144 h (hatching occurs between 120-144 h). Furthermore, neuropil formations with synaptic specializations are present in the rostral part of the pineal organ 108 h after fertilization. At 72 h, the embryonic parapineal parenchyma is already differentiated into parapinealocytes, which give rise to the parapineal tract, and glia-resembling elements. Although parapinealocytes carry cilia (9 × 2 + 0), only a single outer segment of the photoreceptor type could be demonstrated in the parapineal organ of one adult stickleback. Photoreceptors present in the pineal organ of unhatched embryos are hardly involved in visual functions, but may already at this early developmental stage serve as photoneuroendocrine transducers.
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| 18. |
- Ekström, Peter, et al.
(författare)
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The Monoaminergic Paraventricular Organ in the Teleost Ictalurus nebulosus LeSueur, with Special Reference to Its Vascularization
- 1982
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Ingår i: Acta Zoologica. - : Wiley. - 0001-7272 .- 1463-6395. ; 63:1, s. 45-54
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Tidskriftsartikel (refereegranskat)abstract
- Specific, fluorescent, subependymal perikarya were found in the pars anterior of the paraventricular organ (PVOpa), in the nucleus recessus lateralis (NRL) and in the nucleus recessus posterioris (NRP). No fluorescent perikarya were present in the nucleus lateralis tuberis (NLT). Fluorescent nerve tracts connect the PVOpa and the NRL with the NRP, and interconnect the paired NRP. The nucleus preopticus (NPO) and the NLT receive a large input of aminergic nerve fibers. The monoaminergic nuclei are well vascularized, and their vascular plexes seem to be connected. A capillary plexus is situated dorsal to the NRP and exhibits no contact with the pituitary. It is surrounded by the prominent fluorescent tracts connecting the aminergic nuclei. 1982 The Royal Swedish Academy of Sciences
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| 19. |
- Hauck, Stefanie M, et al.
(författare)
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Differential modification of phosducin protein in degenerating rd1 ret is associated with constitutively active CaMKII in rod outer segments.
- 2006
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Ingår i: Molecular & Cellular Proteomics. - 1535-9484. ; 5:2, s. 324-336
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Tidskriftsartikel (refereegranskat)abstract
- Retinitis pigmentosa comprises a heterogeneous group of incurable progressive blinding diseases with unknown pathogenic mechanisms. The retinal degeneration 1 (rd1) mouse is a retinitis pigmentosa model that carries a mutation in a rod photoreceptor-specific phosphodiesterase gene, leading to rapid degeneration of these cells. Elucidation of the molecular differences between rd1 and healthy retinae is crucial for explaining this degeneration and could assist in suggesting novel therapies. Here we used high resolution proteomics to compare the proteomes of the rd1 mouse retina and its congenic, wildtype counterpart at postnatal day 11 when photoreceptor death is profound. Over 3000 protein spots were consistently resolved by two-dimensional gel electrophoresis and subjected to a rigorous filtering procedure involving computer-based spot analyses. Five proteins were accepted as being differentially expressed in the rd1 model and subsequently identified by mass spectrometry. The difference in one such protein, phosducin, related to an altered modification pattern in the rd1 retina rather than to changed expression levels. Additional experiments showed phosducin in healthy retinae to be highly phosphorylated in the dark- but not in the light-adapted phase. In contrast, rd1 phosducin was highly phosphorylated irrespective of light status, indicating a dysfunctional rd1 light/dark response. The increased rd1 phosducin phosphorylation coincided with increased activation of calcium/calmodulin-activated protein kinase II, which is known to utilize phosducin as a substrate. Given the increased rod calcium levels present in the rd1 mutation, calcium-evoked overactivation of this kinase may be an early and long sought for step in events leading to photoreceptor degeneration in the rd1 mouse.
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| 20. |
- Johnson, Leif, et al.
(författare)
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Differential Akt activation in the photoreceptors of normal and rd1 mice.
- 2005
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Ingår i: Cell and Tissue Research. - : Springer Science and Business Media LLC. - 1432-0878 .- 0302-766X. ; 320:2, s. 213-222
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Tidskriftsartikel (refereegranskat)abstract
- Retinitis pigmentosa is a blinding disease in which unknown mechanisms cause the degeneration of retinal photoreceptors. The retinal degeneration (rd1) mouse is a relevant model for this condition, since it carries a mutation also found in some forms of retinitis pigmentosa. To understand the degenerative process in the rd1 mouse, we must identify the survival and apoptosis-related signaling pathways in its photoreceptors and determine whether signaling differs from that in normal mice. The phosphatidylinositol 3-kinase/Akt kinase pathway promotes survival in several different cell types. The purpose of the present study has been to compare Akt activity in retinal cells of normal and rd1 mice. We have found that, in normal mice, Akt becomes activated in the retina in a developmentally regulated and cell-type-specific fashion, encompassing essentially all retinal cells. In most cell types, once Akt activation has begun, it remains in this state throughout life. An exception is seen in the rod photoreceptors, in which Akt is activated only transiently during their development. The rd1 retina behaves identically in all but one respect, namely that the activation of Akt in rod photoreceptors persists until these cells undergo apoptosis. Thus, Akt may participate in constitutive survival processes in retinal neurons, except in rod photoreceptors in which the role of this pathway may be restricted to the developmental period. However, Akt activation in the rods may be part of a defense mechanism initiated in response to insults, such as the retinal degeneration seen in the rd1 mouse.
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| 21. |
- Kaur, Jasvir, et al.
(författare)
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Calpain and PARP Activation during Photoreceptor Cell Death in P23H and S334ter Rhodopsin Mutant Rats
- 2011
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:7
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Tidskriftsartikel (refereegranskat)abstract
- Retinitis pigmentosa (RP) is a heterogeneous group of inherited neurodegenerative diseases affecting photoreceptors and causing blindness. Many human cases are caused by mutations in the rhodopsin gene. An important question regarding RP pathology is whether different genetic defects trigger the same or different cell death mechanisms. To answer this question, we analysed photoreceptor degeneration in P23H and S334ter transgenic rats carrying rhodopsin mutations that affect protein folding and sorting respectively. We found strong activation of calpain and poly(ADP-ribose) polymerase (PARP) in both mutants, concomitant with calpastatin down-regulation, increased oxidative DNA damage and accumulation of PAR polymers. These parameters were strictly correlated with the temporal progression of photoreceptor degeneration, mirroring earlier findings in the phosphodiesterase-6 mutant rd1 mouse, and suggesting execution of non-apoptotic cell death mechanisms. Interestingly, activation of caspases-3 and -9 and cytochrome c leakage-key events in apoptotic cell death-were observed only in the S334ter mutant, which also showed increased expression of PARP-1. The identification of the same metabolic markers triggered by different mutations in two different species suggests the existence of common cell death mechanisms, which is a major consideration for any mutation independent treatment.
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| 22. |
- Miranda, Maria, et al.
(författare)
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Antioxidants rescue photoreceptors in rd1 mice: Relationship with thiol metabolism
- 2010
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Ingår i: Free Radical Biology & Medicine. - : Elsevier BV. - 0891-5849. ; 48:2, s. 216-222
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Tidskriftsartikel (refereegranskat)abstract
- We have previously shown that the use of a combination of antioxidants delayed the degeneration process in rd1 mouse retina. In an effort to understand the mechanism of action of these substances (zeaxanthin, lutein, alpha-lipoic acid, glutathione, and Lycium barbarum extract) the changes in the levels of several proteins and oxidative stress markers in the rd1 retina have been studied. The treatment increased glutathione peroxidase activity and glutathione levels and decreased cystine concentrations in rd1 retinas. Considering all the results obtained from treated and untreated animals, a high correlation was present between glutathione concentration and glutathione peroxidase activity, and there was a negative correlation between glutathione retinal concentration and number of TUNEL-positive cells. No difference was observed between the numbers of nNOS- and NADPH-diaphorase-positive cells in treated and untreated rd1 mice. Thiol contents and thiol-dependent peroxide metabolism seem to be directly related to the survival of photoreceptors in rd1 mouse retina. (C) 2009 Elsevier Inc. All rights reserved.
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| 23. |
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| 24. |
- Paquet-Durand, Francois, et al.
(författare)
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A key role for cyclic nucleotide gated (CNG) channels in cGMP-related retinitis pigmentosa
- 2011
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 20:5, s. 941-947
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Tidskriftsartikel (refereegranskat)abstract
- The rd1 natural mutant is one of the first and probably the most commonly studied mouse model for retinitis pigmentosa (RP), a severe and frequently blinding human retinal degeneration. In several decades of research, the link between the increase in photoreceptor cGMP levels and the extremely rapid cell death gave rise to a number of hypotheses. Here, we provide clear evidence that the presence of cyclic nucleotide gated (CNG) channels in the outer segment membrane is the key to rod photoreceptor loss. In Cngb1(-/-) x rd1 double mutants devoid of regular CNG channels, cGMP levels are still pathologically high, but rod photoreceptor viability and outer segment morphology are greatly improved. Importantly, cone photoreceptors, the basis for high-resolution daylight and colour vision, survived and remained functional for extended periods of time. These findings strongly support the hypothesis of deleterious calcium (Ca2+)-influx as the cause of rapid rod cell death and highlight the importance of CNG channels in this process. Furthermore, our findings suggest that targeting rod CNG channels, rather than general Ca2+-channel blockade, is a most promising symptomatic approach to treat otherwise incurable forms of cGMP-related RP.
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| 25. |
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| 26. |
- Paquet-Durand, Francois, et al.
(författare)
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Photoreceptor rescue and toxicity induced by different calpain inhibitors
- 2010
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 115:4, s. 930-940
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Tidskriftsartikel (refereegranskat)abstract
- P>Photoreceptor degeneration is the hallmark of a group of inherited blinding diseases collectively termed retinitis pigmentosa (RP); a major cause of blindness in humans. RP is at present untreatable and the underlying neurodegenerative mechanisms are largely unknown, even though the genetic causes are often established. The activation of calpain-type proteases may play an important role in cell death in various neuronal tissues, including the retina. We therefore tested the efficacy of two different calpain inhibitors in preventing cell death in the retinal degeneration (rd1) human homologous mouse model for RP. Pharmacological inhibition of calpain activity in rd1 organotypic retinal explants had ambiguous effects on photoreceptor viability. Calpain inhibitor XI had protective effects when applied for short periods of time (16 h) but demonstrated substantial levels of toxicity in both wild-type and rd1 retina when used over several days. In contrast, the highly specific calpain inhibitor calpastatin peptide reduced photoreceptor cell death in vitro after both short and prolonged exposure, an effect that was also evident after in vivo application via intravitreal injection. These findings highlight the importance of calpain activation for photoreceptor cell death but also for photoreceptor survival and propose the use of highly specific calpain inhibitors to prevent or delay RP.
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| 27. |
- Paquet-Durand, Francois, et al.
(författare)
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PKG activity causes photoreceptor cell death in two retinitis pigmentosa models
- 2009
-
Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 108:3, s. 796-810
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Tidskriftsartikel (refereegranskat)abstract
- Photoreceptor degeneration in retinitis pigmentosa is one of the leading causes of hereditary blindness in the developed world. Although causative genetic mutations have been elucidated in many cases, the underlying neuronal degeneration mechanisms are still unknown. Here, we show that activation of cGMP-dependent protein kinase (PKG) hallmarks photoreceptor degeneration in rd1 and rd2 human homologous mouse models. When induced in wild-type retinae, PKG activity was both necessary and sufficient to trigger cGMP-mediated photoreceptor cell death. Target-specific, pharmacological inhibition of PKG activity in both rd1 and rd2 retinae strongly reduced photoreceptor cell death in organotypic retinal explants. Likewise, inhibition of PKG in vivo, using three different application paradigms, resulted in robust photoreceptor protection in the rd1 retina. These findings suggest a pivotal role for PKG activity in cGMP-mediated photoreceptor degeneration mechanisms and highlight the importance of PKG as a novel target for the pharmacological intervention in RP.
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| 28. |
- Sancho-Pelluz, J., et al.
(författare)
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Excessive HDAC activation is critical for neurodegeneration in the rd1 mouse
- 2010
-
Ingår i: Cell Death & Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 1
-
Tidskriftsartikel (refereegranskat)abstract
- Inherited retinal degenerations, collectively termed retinitis pigmentosa (RP), constitute one of the leading causes of blindness in the developed world. RP is at present untreatable and the underlying neurodegenerative mechanisms are unknown, even though the genetic causes are often established. Acetylation and deacetylation of histones, carried out by histone acetyltransferases (HATs) and histone deacetylases (HDACs), respectively, affects cellular division, differentiation, death and survival. We found acetylation of histones and probably other proteins to be dramatically reduced in degenerating photoreceptors in the rd1 human homologous mouse model for RP. Using a custom developed in situ HDAC activity assay, we show that overactivation of HDAC classes I/II temporally precedes photoreceptor degeneration. Moreover, pharmacological inhibition of HDACs I/II activity in rd1 organotypic retinal explants decreased activity of poly-ADP-ribose-polymerase and strongly reduced photoreceptor cell death. These findings highlight the importance of protein acetylation for photoreceptor cell death and survival and propose certain HDAC classes as novel targets for the pharmacological intervention in RP. Cell Death and Disease (2010) 1, e24; doi:10.1038/cddis.2010.4; published online 11 February 2010
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| 29. |
- Sancho-Pelluz, J., et al.
(författare)
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Photoreceptor Cell Death Mechanisms in Inherited Retinal Degeneration
- 2008
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Ingår i: Molecular Neurobiology. - : Springer Science and Business Media LLC. - 1559-1182 .- 0893-7648. ; 38:3, s. 253-269
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Forskningsöversikt (refereegranskat)abstract
- Photoreceptor cell death is the major hallmark of a group of human inherited retinal degenerations commonly referred to as retinitis pigmentosa (RP). Although the causative genetic mutations are often known, the mechanisms leading to photoreceptor degeneration remain poorly defined. Previous research work has focused on apoptosis, but recent evidence suggests that photoreceptor cell death may result primarily from non-apoptotic mechanisms independently of AP1 or p53 transcription factor activity, Bcl proteins, caspases, or cytochrome c release. This review briefly describes some animal models used for studies of retinal degeneration, with particular focus on the rd1 mouse. After outlining the major features of different cell death mechanisms in general, we then compare them with results obtained in retinal degeneration models, where photoreceptor cell death appears to be governed by, among other things, changes in cyclic nucleotide metabolism, downregulation of the transcription factor CREB, and excessive activation of calpain and PARP. Based on recent experimental evidence, we propose a putative non-apoptotic molecular pathway for photoreceptor cell death in the rd1 retina. The notion that inherited photoreceptor cell death is driven by non-apoptotic mechanisms may provide new ideas for future treatment of RP.
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| 30. |
- Sancho Pelluz, Javier, et al.
(författare)
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Sialoadhesin Expression in Intact Degenerating Retinas and Following Transplantation.
- 2008
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 49, s. 5602-5610
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Resident microglial cells normally do not express sialoadhesin (a sialic acid binding receptor), whereas recruited inflammatory macrophages have been shown to do so. The expression of sialoadhesin was examined here in the course of photoreceptor cell degeneration and following transplantation. Methods: Sialoadhesin expression was analyzed in retinas of rd1 and rds mice. For transplantation studies, neonatal (P2) retinal cells derived from GFP mice were injected intraocularly in adult rd1 mice and controls. Antibodies recognizing different sialoadhesin epitopes, CD11b, and MHC-II were used to identify activated microglial cells in intact retinas and 21 days post-transplantation. Results: In rd1 mice, a few CD11b-positive cells were observed in the outer nuclear layer in the central retina at postnatal day (P) 11 and in increasing numbers between P12 21. In rds mice, CD11b-expressing cells were found from P16 and onwards. No sialoadhesin expressing cells were observed within the rd1 or rds mouse retinas at any of the ages examined (up to P150). Specific staining was only observed in cells found in the vitreal margin of the retina and in surrounding tissues (sclera, cornea, ciliary body, choroid). Following transplantation to normal and rd1 mice, a variable number of sialoadhesin-positive cells were detected within the grafts, in the graft-host interface, and in the subretinal space. Conclusions: The significant activation of microglia/macrophages observed in the various stages of degeneration in rd1 and rds mouse retinas is not accompanied by sialoadhesin expression. However, sialoadhesin-expressing cells are observed following transplantation. The occurrence of such cells could be of significance for the integration and long term survival of retinal grafts, as expression of sialoadhesin could facilitate other phagocytic receptors.
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| 31. |
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| 32. |
- van Veen, Theo, et al.
(författare)
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Retinal S-antigen: immunocytochemical and immunochemical studies on distribution in animal photoreceptors and pineal organs
- 1986
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Ingår i: Experimental Biology. ; 45, s. 15-25
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Tidskriftsartikel (refereegranskat)abstract
- Antiserum against bovine retinal S-antigen, a soluble protein (MW = 50 kDa) thought to be involved in phototransduction, was used in an immunohistochemical and immunochemical study of vertebrate eyes and pineal systems and invertebrate photoreceptor organs. Positive reactions, not seen with antiserum preabsorbed with highly purified S-antigen, were observed in planarian and starfish ocelli; scallop eyes; polychaete eye; crayfish compound eye; lamprey, salmon, frog, turtle, quail and hamster eyes. A specific reaction was also seen in the pineal organ of all the vertebrates examined, albeit weak in turtle and quail. In addition, several structures associated with photoreceptor organs, including the reduced frontal eyes of crayfish, the organ of Bellonci in crayfish eyestalk, and bipolar cells resembling those giving rise to Landolt's clubs in quail and golden hamster retinae, were immunopositive. Immunochemical studies revealed the presence of a single immunopositive band of protein which was similar but not identical in size in all vertebrate eyes and pineal organs (except that of chicken pineal) and invertebrate tissue examined. The wide distribution of positive reaction in photoreceptive tissue indicates that the retinal S-antigen determinant has been highly conserved during evolution.
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| 33. |
- van Veen, Theo, et al.
(författare)
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Serotonin and opsin immunoreactivities in the developing pineal organ of the three-spined stickleback, Gasterosteus aculeatus L.
- 1984
-
Ingår i: Cell and Tissue Research. - 0302-766X. ; 237:3, s. 559-564
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Tidskriftsartikel (refereegranskat)abstract
- 5-hydroxytryptamine (5-HT, serotonin)- and opsin-immunoreactive sites were studied in the developing pineal complex of the stickleback, Gasterosteus aculeatus L., by use of light-microscopic indirect immunoperoxidase techniques. 5-HT immunoreactivity first occurs in the pineal organ at the age of 80 h after fertilization and appears to be localized in cells of the photoreceptor type. The outer segments of a few pineal photosensory cells exhibit opsin immunoreactivity at the age of 84 h after fertilization. The number of cells seems to increase until the pineal organ is completely developed. The increase in the number of 5-HT immunoreactive perikarya runs parallel in time to that of the opsinimmunoreactive outer segments. The cells of the parapineal organ show neither opsin nor 5-HT immunoreactivity. The retina of the embryonic stickleback does not display opsin immunoreactivity until after hatching, which takes place about 144 h after fertilization. These results suggest, in the three-spined stickleback, an earlier light-perception capacity for the developing pineal organ than for the retina.
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| 34. |
- Vlachantoni, Dafni, et al.
(författare)
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Evidence of severe mitochondrial oxidative stress and a protective effect of low oxygen in mouse models of inherited photoreceptor degeneration
- 2011
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 20:2, s. 322-335
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Tidskriftsartikel (refereegranskat)abstract
- The role of oxidative stress within photoreceptors (PRs) in inherited photoreceptor degeneration (IPD) is unclear. We investigated this question using four IPD mouse models (Pde6b(rd1/rd1), Pde6b(atrd1/atrd1), Rho(-/-) and Prph2(rds/rds)) and compared the abundance of reduced glutathione (GSH) and the activity of mitochondrial NADH:ubiquinone oxidoreductase (complex I), which is oxidative stress sensitive, as indirect measures of redox status, in the retinas of wild type and IPD mice. All four IPD mutants had significantly reduced retinal complex I activities (14-29% of wild type) and two showed reduced GSH, at a stage prior to the occurrence of significant cell death, whereas mitochondrial citrate synthase, which is oxidative stress insensitive, was unchanged. We orally administered the mitochondrially targeted anti oxidant MitoQ in order to reduce oxidative stress but without any improvement in retinal complex I activity, GSH or rates of PR degeneration. One possible source of oxidative stress in IPDs is oxygen toxicity in the outer retina due to reduced consumption by PR mitochondria. We therefore asked whether a reduction in the ambient O-2 concentration might improve PR survival in Pde6b(rd1/rd1) retinal explants either directly, by reducing reactive oxygen species formation, or indirectly by a neuroprotective mechanism. Pde6b(rd1/rd1) retinal explants cultured in 6% O-2 showed 31% less PR death than normoxic explants. We conclude that (i) mitochondrial oxidative stress is a significant early feature of IPDs; (ii) the ineffectiveness of MitoQ may indicate its inability to reduce some mediators of oxidative stress, such as hydrogen peroxide; and (iii) elucidation of the mechanisms by which hypoxia protects mutant PRs may identify novel neuroprotective pathways in the retina.
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| 35. |
- Zhang, Yiqin, et al.
(författare)
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Integration between abutting retinas: Role of glial structures and associated molecules at the interface
- 2004
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 45:12, s. 4440-4449
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. Integration between subretinal grafts and the host retina is limited in part by the presence of a barrier at the graft-host interface. This study was conducted to identify factors that may contribute to this barrier, by examining the distribution of glial structures and associated molecules in different setups of overlapping retinal pieces. METHODS. Neuroretinal tissue derived from mice that express green fluorescent protein (GFP) was fragmented and transplanted into the subretinal space of adult rd1 mice. In an in vitro system, two retinal pieces, derived from GFP and rd1 mice, respectively, were placed overlapping each other and forming either laminar-laminar pairs or fragment-laminar pairs. The glia-associated markers analyzed included glial fibrillary acidic protein (GFAP), cellular retinaldehyde-binding protein ( CRALBP), and two molecules known to inhibit neurite outgrowth: CD44 and neurocan. Bridging fibers and migrated cells were visualized with GFP fluorescence and retinal cell markers. RESULTS. A thick CRALBP-immunolabeled band was observed in the interface in cultured laminar-laminar pairs, whereas a thinner band was seen in cultured fragment-laminar pairs and in transplants. Accumulation of CD44 and neurocan was also observed in the interface between abutting retinal pieces in all setups. GFP(+) bridging fibers and GFP(+) cells (some of which coexpressed neuronal markers) were observed within the abutting rd1 retina in some areas. However, such integration occurred exclusively where CRALBP, CD44, and neurocan immunolabeling appeared disrupted in the interface, but coincided with high GFAP expression within the rd1 retina. CONCLUSIONS. The results demonstrate that, on the one hand, an accumulation of glial-associated inhibitory molecules in the interface correlates with limited integration between overlapping retinal pieces. On the other hand, glial reactivity within the rd1 retina does not appear to be incompatible with integration.
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| 36. |
- Zhang, Yiqin, et al.
(författare)
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Neuronal integration in an abutting-retinas culture system
- 2003
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 44:11, s. 4936-4946
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Limited integration is consistently observed between subretinal transplants and host retinas. In the current study, an in vitro model system for studying connections forming between two abutting retinas was developed.METHODS: Neuroretinas were dissected from normal wild-type (WT) mice and green fluorescent protein (GFP) transgenic mice (obtained at postnatal days [P]0, P5, or P60), as well as from adult rd mice. Pieces from two different retinas (WT-WT, GFP-WT, GFP-rd) were placed side-by-side (contacting each other at the margins) or overlapping each other in organ cultures for 7 or 12 days. The abutting retinal pieces derived from animals of the same age (P5-P5; P60-P60) or of different ages (P0-P60; P5-P60). Retinal cells and fibers were visualized in wholemount preparations and in cross sections by immunocytochemistry using antibodies against neurofilament (NF+), neuronal nitric oxide synthase (NOS+), and protein kinase C (PKC+) and by GFP fluorescence (GFP+).RESULTS: In side-by-side pairs (WT-WT, GFP-WT), numerous horizontal cell fibers (NF+) and amacrine cell fibers (NOS+) crossed the interface between the two pieces, forming continuous plexiform layers. In overlapping pairs, NF+, NOS+, and PKC+ fibers displayed parallel plexiform layers, and no crossover of fibers was observed in any of the pair combinations examined (WT-WT, GFP-WT, GFP-rd). Some integration was seen only in small areas where the structure of both retinal pieces was disrupted at the interface.CONCLUSIONS: The results demonstrate the ability of neurites to extend between abutting retinas and to make appropriate target choices when they are placed side-by-side. However, this ability is limited when they overlap each other, similar to that observed in subretinal transplantation.
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