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[This corrects the article DOI: 10.1371/journal.pone.0067983.].
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Oxidative stress alters physiological function in most biological tissues and can lead to cell death. In the retina, oxidative stress initiates a cascade of events leading to focal loss of RPE and photoreceptors, which is thought to be a major contributing factor to geographic atrophy. Despite these implications, the molecular regulation of RPE oxidative stress under normal and pathological conditions remains largely unknown. A better understanding of the mechanisms involved in regulating RPE and photoreceptors oxidative stress response is greatly needed. To this end we evaluated photoreceptor and RPE changes in mice deficient in DJ-1, a protein that is thought to be important in protecting cells from oxidative stress. Young (3 months) and aged (18 months) DJ-1 knockout (DJ-1 KO) and age-matched wild-type mice were examined. In both group of aged mice, scanning laser ophthalmoscopy (SLO) showed the presence of a few autofluorescent foci. The 18 month-old DJ-1 KO retinas were also characterized by a noticeable increase in RPE fluorescence to wild-type. Optical coherence tomography (OCT) imaging demonstrated that all retinal layers were present in the eyes of both DJ-1 KO groups. ERG comparisons showed that older DJ-1 KO mice had reduced sensitivity under dark- and light-adapted conditions compared to age-matched control. Histologically, the RPE contained prominent vacuoles in young DJ-1 KO group with the appearance of enlarged irregularly shaped RPE cells in the older group. These were also evident in OCT and in whole mount RPE/choroid preparations labeled with phalloidin. Photoreceptors in the older DJ-1 KO mice displayed decreased immunoreactivity to rhodopsin and localized reduction in cone markers compared to the wild-type control group. Lower levels of activated Nrf2 were evident in retina/RPE lysates in both young and old DJ-1 KO mouse groups compared to wild-type control levels. Conversely, higher levels of protein carbonyl derivatives and iNOS immunoreactivity were detected in retina/RPE lysates from both young and old DJ-1 KO mice. These results demonstrate that DJ-1 KO mice display progressive signs of retinal/RPE degeneration in association with higher levels of oxidative stress markers. Collectively this analysis indicates that DJ-1 plays an important role in protecting photoreceptors and RPE from oxidative damage during aging.
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Envejecimiento/genética , Estrés Oxidativo/genética , Proteína Desglicasa DJ-1/genética , Degeneración Retiniana/genética , Envejecimiento/metabolismo , Envejecimiento/patología , Animales , Modelos Animales de Enfermedad , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Células Fotorreceptoras de Vertebrados/metabolismo , Células Fotorreceptoras de Vertebrados/patología , Degeneración Retiniana/fisiopatología , Epitelio Pigmentado de la Retina/metabolismo , Epitelio Pigmentado de la Retina/patología , Rodopsina/metabolismoRESUMEN
BACKGROUND: The goal of this study was to define the histopathology of the retina in donor eyes from a patient with Stargardt disease (STGD1) due to compound mutations in the ABCA4 gene. MATERIALS AND METHODS: Eyes were obtained from a 66-year-old female and fixed within 18 hours postmortem. The fundi of the posterior globes were evaluated with macroscopic, SLO and OCT imaging. The perifoveal and peripheral regions were processed for electron microscopy and immunocytochemistry using cell specific antibodies. Two age-similar normal eyes were used as controls. Prior ophthalmic examinations and genetic test results were also reviewed. RESULTS: All imaging modalities showed scattered bone spicules in the peripheral retina. Atrophy of the RPE was present around the optic nerve as evidenced by the absence of SLO autofluorescence. Histology analysis showed a severely degenerated fovea with little evidence of any retinal layering or remaining RPE. The fovea was severely degenerated, with little evidence of any retinal cell layer, including the RPE. In contrast, retinal nuclear layers were present in the periphery. The perifoveal region contained few cones labeled with cone-specific antibodies; some rhodopsin-labeled cells, reactive glia labeled with GFAP; and decreased autofluorescence of the RPE. The fovea was free of cone-specific labeling, contained a few disorganized rhodopsin-labeled cells and showed substantial GFAP labeling and no autofluorescent material in the retina. The periphery displayed stubby cells labeled with cone-specific antibodies, decreased rhodopsin-labeled cells, increased GFAP staining, and autofluorescent granules in the RPE. CONCLUSIONS: The histopathology of the retina in this patient with Stargardt disease displayed a highly degenerated fovea. In all retinal locations studied, cones were more severely affected than rods.
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Transportadoras de Casetes de Unión a ATP/genética , Degeneración Macular/congénito , Mutación , Células Fotorreceptoras de Vertebrados/patología , Epitelio Pigmentado de la Retina/patología , Anciano , Biomarcadores/metabolismo , Coroides/patología , Proteínas del Ojo/metabolismo , Femenino , Humanos , Inmunohistoquímica , Degeneración Macular/genética , Degeneración Macular/metabolismo , Degeneración Macular/patología , Microscopía Electrónica , Persona de Mediana Edad , Oftalmoscopía , Células Fotorreceptoras de Vertebrados/metabolismo , Epitelio Pigmentado de la Retina/metabolismo , Enfermedad de Stargardt , Donantes de Tejidos , Tomografía de Coherencia ÓpticaRESUMEN
DJ-1/PARK7 mutations or deletions cause autosomal recessive early onset Parkinson's disease (PD). Thus, DJ-1 protein has been extensively studied in brain and neurons. PD patients display visual symptoms; however, the visual symptoms specifically attributed to PD patients carrying DJ-1/PARK7 mutations are not known. In this study, we analyzed the structure and physiology of retinas of 3- and 6-month-old DJ-1 knockout (KO) mice to determine how loss of function of DJ-1 specifically contributes to the phenotypes observed in PD patients. As compared to controls, the DJ-1 KO mice displayed an increase in the amplitude of the scotopic ERG b-wave and cone ERG, while the amplitude of a subset of the dc-ERG components was decreased. The main structural changes in the DJ-1 KO retinas were found in the outer plexiform layer (OPL), photoreceptors and retinal pigment epithelium (RPE), which were observed at 3 months and progressively increased at 6 months. RPE thinning and structural changes within the OPL were observed in the retinas in DJ-1 KO mice. DJ-1 KO retinas also exhibited disorganized outer segments, central decrease in red/green cone opsin staining, decreased labeling of ezrin, broader distribution of ribeye labeling, decreased tyrosine hydroxylase in dopaminergic neurons, and increased 7,8-dihydro-8-oxoguanine-labeled DNA oxidation. Accelerated outer retinal atrophy was observed in DJ-1 KO mice after selective oxidative damage induced by a single tail vein injection of NaIO3, exposing increased susceptibility to oxidative stress. Our data indicate that DJ-1-deficient retinas exhibit signs of morphological abnormalities and physiological dysfunction in association with increased oxidative stress. Degeneration of RPE cells in association with oxidative stress is a key hallmark of age-related macular degeneration (AMD). Therefore, in addition to detailing the visual defects that occur as a result of the absence of DJ-1, our data is also relevant to AMD pathogenesis.
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ADN/genética , Mutación , Proteínas Oncogénicas/genética , Peroxirredoxinas/genética , Degeneración Retiniana/genética , Epitelio Pigmentado de la Retina/metabolismo , Animales , Western Blotting , Análisis Mutacional de ADN , Modelos Animales de Enfermedad , Electrorretinografía , Femenino , Genotipo , Inmunohistoquímica , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microscopía Electrónica de Transmisión , Proteínas Oncogénicas/biosíntesis , Estrés Oxidativo , Peroxirredoxinas/biosíntesis , Reacción en Cadena de la Polimerasa , Proteína Desglicasa DJ-1 , Degeneración Retiniana/patología , Degeneración Retiniana/fisiopatología , Epitelio Pigmentado de la Retina/fisiopatología , Epitelio Pigmentado de la Retina/ultraestructura , Transducción de SeñalRESUMEN
PURPOSE: To evaluate the histopathology in donor eyes from patients with autosomal dominant retinitis pigmentosa (ADRP) caused by p.P23H, p.P347T and p.P347L rhodopsin ( RHO ) gene mutations. METHODS: Eyes from a 72-year-old male (donor 1), an 83-year-old female (donor 2), an 80-year-old female (donor 3), and three age-similar normal eyes were examined macroscopically, by scanning laser ophthalmoscopy and optical coherence tomography imaging. Perifoveal and peripheral pieces were processed for microscopy and immunocytochemistry with markers for photoreceptor cells. RESULTS: DNA analysis revealed RHO mutations c.68C>A (p.P23H) in donor 1, c.1040C>T (p.P347L) in donor 2 and c.1039C>A (p.P347T) in donor 3. Histology of the ADRP eyes showed retinas with little evidence of stratified nuclear layers in the periphery and a prominent inner nuclear layer present in the perifoveal region in the p.P23H and p.P347T eyes, while it was severely atrophic in the p.P347L eye. The p.P23H and p.P347T mutations cause a profound loss of rods in both the periphery and perifovea, while the p.P347L mutation displays near complete absence of rods in both regions. All three rhodopsin mutations caused a profound loss of cones in the periphery. The p.P23H and p.P347T mutations led to the presence of highly disorganized cones in the perifovea. However, the p.P347L mutation led to near complete absence of cones also in the perifovea. CONCLUSIONS: Our results support clinical findings indicating that mutations affecting residue P347 develop more severe phenotypes than those affecting P23. Furthermore, our results indicate a more severe phenotype in the p.P347L retina as compared to the p.P347T retina.
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Mutación Puntual , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras Retinianas Bastones/patología , Retinitis Pigmentosa/genética , Retinitis Pigmentosa/patología , Rodopsina/genética , Anciano , Anciano de 80 o más Años , Arrestina/metabolismo , Electrorretinografía , Femenino , Humanos , Inmunohistoquímica , Masculino , Oftalmoscopía , Linaje , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Bastones/metabolismo , Rodopsina/metabolismo , Opsinas de Bastones/metabolismo , Donantes de Tejidos , Tomografía de Coherencia ÓpticaRESUMEN
BALB/cJ mice housed under normal vivarium lighting conditions can exhibit profound retinal abnormalities, including retinal infoldings, autofluorescent inflammatory cells, and photoreceptor degeneration. To explore the sensitivity of the outer retina to cyclic lighting during aging, a cohort of BALB/cJ mice was evaluated with Scanning Laser Ophthalmoscopy (SLO), Spectral-Domain Optical Coherence Tomography (OCT) and conventional histopathology. Mice were bred and reared in a low-illuminance (extracage/intracage: 13 lx/1 lx) vivarium under cyclic light (14 h light: 10 h dark). Retinal imaging (around postnatal day 70) was performed to screen for any pre-existing abnormalities and to establish a baseline. Mice with normal retinas were separated into groups (A, B, C) and placed on bottom (Groups A & B) or top (Group C) of the cage racks where cage illumination was <10 & 150 lx respectively. Experimental groups B & C were imaged multiple times over a 17 month period. Mice from group A (controls) were imaged only once post-baseline at various times for comparison to groups B & C. Mice were assessed by histology at 8, 15, 20, 36, and 56 weeks and immunohistochemistry at 15 weeks post-baseline. SLO and OCT retinal images were measured and the resulting trends displayed as a function of age and light exposure. Retinal lesions (RL) and autofluorescent foci (AFF) were identified with histology as photoreceptor layer infoldings (IF) and localized microglia/macrophages (MM), respectively. Few RL and AFF were evident at baseline. Retinal infoldings were the earliest changes followed by subjacent punctate autofluorescent MM. The colocalization of IF and MM suggests a causal relationship. The incidence of these pathological features increased in all groups relative to baseline. OCT imaging revealed thinning of the outer nuclear layer (ONL) in all groups at 1 year relative to baseline. ONL thinning followed an exponential rate of change but the decay constant varied depending on intensity of illumination of the groups. Advanced age and top row illuminance conditions resulted in significant photoreceptor cell loss as judged by decreased thickness of the ONL. Photoreceptor loss was preceded by both retinal infoldings and the presence of autofluorescent inflammatory cells in the outer retina, suggesting that these changes are early indicators of light toxicity in the BALB/cJ mouse.
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Envejecimiento/efectos de la radiación , Luz/efectos adversos , Ratones Endogámicos BALB C/fisiología , Traumatismos Experimentales por Radiación/patología , Retina/efectos de la radiación , Degeneración Retiniana/etiología , Envejecimiento/fisiología , Animales , Ratones , Microscopía Fluorescente , Retina/patología , Degeneración Retiniana/patología , Tomografía de Coherencia ÓpticaRESUMEN
To evaluate the retinal histopathology in donor eyes from patients with autosomal recessive retinitis pigmentosa (arRP) caused by EYS mutations. Eyes from a 72-year-old female (donor 1, family 1), a 91-year-old female (donor 2, family 2), and her 97-year-old sister (donor 3, family 2) were evaluated with macroscopic, scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) imaging. Age-similar normal eyes and an eye donated by donor 1's asymptomatic mother (donor 4, family 1) were used as controls. The perifovea and peripheral retina were processed for microscopy and immunocytochemistry with markers for cone and rod photoreceptor cells. DNA analysis revealed EYS mutations c.2259 + 1G > A and c.2620C > T (p.Q874X) in family 1, and c.4350_4356del (p.I1451Pfs*3) and c.2739-?_3244 + ?del in family 2. Imaging studies revealed the presence of bone spicule pigment in arRP donor retinas. Histology of all three affected donor eyes showed very thin retinas with little evidence of stratified nuclear layers in the periphery. In contrast, the perifovea displayed a prominent inner nuclear layer. Immunocytochemistry analysis demonstrated advanced retinal degenerative changes in all eyes, with near-total absence of rod photoreceptors. In addition, we found that the perifoveal cones were more preserved in retinas from the donor with the midsize genomic rearrangement (c.4350_4356del (p.I1451Pfs*3) and c.2739-?_3244 + ?del) than in retinas from the donors with the truncating (c.2259 + 1G > A and c.2620C > T (p.Q874X) mutations. Advanced retinal degenerative changes with near-total absence of rods and preservation of some perifoveal cones are observed in arRP donor retinas with EYS mutations.
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Proteínas del Ojo/genética , Mutación , Retinitis Pigmentosa/genética , Retinitis Pigmentosa/patología , Anciano , Anciano de 80 o más Años , Análisis Mutacional de ADN , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Hibridación de Ácido Nucleico , Oftalmoscopía , Linaje , Reacción en Cadena de la Polimerasa , Donantes de Tejidos , Tomografía de Coherencia ÓpticaRESUMEN
PURPOSE: Ambient light is both a stimulus for visual function and a regulator of photoreceptor physiology. However, it is not known if light can regulate any aspect of photoreceptor development. The purpose of this study was to investigate whether ambient light is required for the development of mouse rod photoreceptors. METHODS: Newborn mouse pups (C57BL/6) were reared in either cyclic light (LD) or constant dark (DD). Pups were collected at postnatal day (P)5, P10, P17, or P24. We performed retinal morphometric and cell death analysis at P5, P10, and P17. Rhodopsin expression was assessed using immunofluorescence, Western blot, and quantitative RT-PCR analysis. Electroretinograms were performed at P17 and P24. Radioimmunoassay and ELISA were used to follow changes in thyroid hormone levels in the serum and vitreous. RESULTS: In the DD pups, the outer nuclear layer was significantly thinner at P10 and there were higher numbers of apoptotic cells at P5 compared to the LD pups. Rhodopsin expression was lower at P10 and P17 in DD pups. Electroretinogram a-waves were reduced in amplitude at P17 in the DD pups. The DD animals had lower levels of circulating thyroid hormones at P10. Light-mediated changes in thyroid hormones occur as early as P5, as we detected lower levels of total triiodothyronine in the vitreous from the DD animals. Drug-induced developmental hypothyroidism resulted in lower rhodopsin expression at P10. CONCLUSIONS: Our data demonstrate that light exposure during postnatal development is required for rod photoreceptor development and that this effect could be mediated by thyroid hormone signaling.
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Adaptación a la Oscuridad , Degeneración Retiniana/metabolismo , Células Fotorreceptoras Retinianas Bastones/metabolismo , Hormonas Tiroideas/metabolismo , Animales , Animales Recién Nacidos , Western Blotting , Muerte Celular , ADN/genética , Modelos Animales de Enfermedad , Electrorretinografía , Ensayo de Inmunoadsorción Enzimática , Regulación del Desarrollo de la Expresión Génica , Luz , Fototransducción , Ratones , Ratones Endogámicos C57BL , Degeneración Retiniana/genética , Degeneración Retiniana/fisiopatología , Células Fotorreceptoras Retinianas Bastones/patología , Células Fotorreceptoras Retinianas Bastones/efectos de la radiación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rodopsina/biosíntesis , Rodopsina/genética , Rodopsina/efectos de la radiación , Hormonas Tiroideas/efectos de la radiaciónRESUMEN
DJ-1 is a protein expressed in many tissues including the brain where it has been extensively studied due to its association with Parkinson's Disease (PD). DJ-1 was reported to function as an antioxidant, redox-sensitive molecular chaperone, and transcription regulator, which protected cells from oxidative stress by modifying signaling pathways that regulate cell survival. Here we discuss our progress toward characterization of the DJ-1 function in the protection of RPE to oxidative stress.
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Péptidos y Proteínas de Señalización Intracelular/metabolismo , Degeneración Macular/metabolismo , Proteínas Oncogénicas/metabolismo , Estrés Oxidativo/fisiología , Enfermedad de Parkinson/metabolismo , Epitelio Pigmentado de la Retina/metabolismo , Humanos , Degeneración Macular/patología , Proteína Desglicasa DJ-1 , Epitelio Pigmentado de la Retina/patologíaRESUMEN
BACKGROUND: Carboxyethylpyrrole (CEP) adducts are oxidative modifications derived from docosahexaenoate-containing lipids that are elevated in ocular tissues and plasma in age-related macular degeneration (AMD) and in rodents exposed to intense light. The goal of this study was to determine whether light-induced CEP adducts and autoantibodies are modulated by pretreatment with AL-8309A under conditions that prevent photo-oxidative damage of rat retina. AL-8309A is a serotonin 5-HT1A receptor agonist. METHODS: Albino rats were dark adapted prior to blue light exposure. Control rats were maintained in normal cyclic light. Rats were injected subcutaneously 3x with 10 mg/kg AL-8309A (2 days, 1 day and 0 hours) before light exposure for 6 h (3.1 mW/cm(2), λ=450 nm). Animals were sacrificed immediately following light exposure and eyes, retinas and plasma were collected. CEP adducts and autoantibodies were quantified by Western analysis or ELISA. RESULTS: ANOVA supported significant differences in mean amounts of CEP adducts and autoantibodies among the light + vehicle, light + drug and dark control groups from both retina and plasma. Light-induced CEP adducts in retina were reduced ~20% following pretreatment with AL-8309A (n = 62 rats, p = 0.006) and retinal CEP immunoreactivity was less intense by immunohistochemistry. Plasma levels of light-induced CEP adducts were reduced at least 30% (n = 15 rats, p = 0.004) by drug pretreatment. Following drug treatment, average CEP autoantibody titer in light exposed rats (n = 22) was unchanged from dark control levels, and ~20% (p = 0.046) lower than in vehicle-treated rats. CONCLUSIONS: Light-induced CEP adducts in rat retina and plasma were significantly decreased by pretreatment with AL-8309A. These results are consistent with and extend previous studies showing AL-8309A reduces light-induced retinal lesions in rats and support CEP biomarkers as possible tools for monitoring the efficacy of select therapeutics.
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Degeneración Macular/metabolismo , Pirroles/metabolismo , Animales , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Biomarcadores/sangre , Biomarcadores/metabolismo , Modelos Animales de Enfermedad , Ácidos Docosahexaenoicos/química , Ácidos Docosahexaenoicos/metabolismo , Luz/efectos adversos , Degeneración Macular/sangre , Degeneración Macular/inmunología , Masculino , Oxidación-Reducción , Pirroles/sangre , Pirroles/química , Pirroles/inmunología , Ratas , Retina/efectos de los fármacos , Retina/inmunología , Retina/metabolismo , Retina/patologíaRESUMEN
BACKGROUND: DJ-1 is found in many tissues, including the brain, where it has been extensively studied due to its association with Parkinson's disease. DJ-1 functions as a redox-sensitive molecular chaperone and transcription regulator that robustly protects cells from oxidative stress. METHODOLOGY: Retinal pigment epithelial (RPE) cultures were treated with H2O2 for various times followed by biochemical and immunohistological analysis. Cells were transfected with adenoviruses carrying the full-length human DJ-1 cDNA and a mutant construct, which has the cysteine residues at amino acid 46, 53 and 106 mutated to serine (C to S) prior to stress experiments. DJ-1 localization, levels of expression and reactive oxygen species (ROS) generation were also analyzed in cells expressing exogenous DJ-1 under baseline and oxidative stress conditions. The presence of DJ-1 and oxidized DJ-1 was evaluated in human RPE total lysates. The distribution of DJ-1 was assessed in AMD and non-AMD cryosectionss and in isolated human Bruch's membrane (BM)/choroid from AMD eyes. PRINCIPAL FINDINGS: DJ-1 in RPE cells under baseline conditions, displays a diffuse cytoplasmic and nuclear staining. After oxidative challenge, more DJ-1 was associated with mitochondria. Increasing concentrations of H2O2 resulted in a dose-dependent increase in DJ-1. Overexpression of DJ-1 but not the C to S mutant prior to exposure to oxidative stress led to significant decrease in the generation of ROS. DJ-1 and oxDJ-1 intensity of immunoreactivity was significantly higher in the RPE lysates from AMD eyes. More DJ-1 was localized to RPE cells from AMD donors with geographic atrophy and DJ-1 was also present in isolated human BM/choroid from AMD eyes. CONCLUSIONS/SIGNIFICANCE: DJ-1 regulates RPE responses to oxidative stress. Most importantly, increased DJ-1 expression prior to oxidative stress leads to decreased generation of ROS, which will be relevant for future studies of AMD since oxidative stress is a known factor affecting this disease.
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Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Oncogénicas/metabolismo , Estrés Oxidativo , Epitelio Pigmentado de la Retina/metabolismo , Animales , Western Blotting , Línea Celular , Núcleo Celular/metabolismo , Células Cultivadas , Citoplasma/metabolismo , Células HEK293 , Humanos , Peróxido de Hidrógeno/farmacología , Inmunohistoquímica , Péptidos y Proteínas de Señalización Intracelular/genética , Degeneración Macular/metabolismo , Degeneración Macular/patología , Ratones , Ratones Endogámicos C57BL , Microscopía Confocal , Mitocondrias/metabolismo , Mutación , Proteínas Oncogénicas/genética , Oxidantes/farmacología , Oxidación-Reducción , Proteína Desglicasa DJ-1 , Transporte de Proteínas/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Epitelio Pigmentado de la Retina/citología , Epitelio Pigmentado de la Retina/efectos de los fármacosRESUMEN
Deimination is a form of protein posttranslational modification carried out by the peptidyl arginine deiminases (PADs) enzymes. PAD2 is the principal deiminase expressed in the retina. Elevated levels of PAD2 and protein deimination are present in a number of human neurological diseases, with or without ocular manifestation. To define the association of deimination with the pathogenesis of age-related macular degeneration (AMD), we studied protein deimination and PAD2 levels in retinas of AMD donor eyes compared to age-matched non-AMD retinas. Eyes from non-AMD and AMD donors were fixed in 4% paraformaldehyde and 0.5% glutaraldehyde in phosphate buffer. Retina and retinal pigment epithelium (RPE) from donor eyes were processed for immunohistochemical detection and western blotting using antibodies to PAD2 and citrulline residues. The ganglion cell, inner plexiform, inner nuclear and outer nuclear layers were labeled by both PAD2 and citrulline antibodies. Changes in the localization of deiminated residues and PAD2 were evident as the retinal layers were remodeled coincident with photoreceptor degeneration in AMD retinas. Immunodetection of either PAD2 or citrulline residues could not be evaluated in the RPE layer due to the high autofluorescence levels in this layer. Interestingly, higher deimination immunoreactivity was detected in AMD retinal lysates. However, no significant changes in PAD2 were detected in the AMD and non-AMD retinas and RPE lysates. Our observations show increased levels of protein deimination but not PAD2 in AMD retinas and RPE, suggesting a reduced rate of turnover of deiminated proteins in these AMD retinas.
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Hidrolasas/metabolismo , Degeneración Macular/metabolismo , Procesamiento Proteico-Postraduccional/fisiología , Retina/enzimología , Epitelio Pigmentado de la Retina/enzimología , Adulto , Anciano , Anciano de 80 o más Años , Citrulina/metabolismo , Bancos de Ojos , Femenino , Humanos , Inmunohistoquímica , Degeneración Macular/patología , Masculino , Persona de Mediana Edad , Arginina Deiminasa Proteína-Tipo 2 , Desiminasas de la Arginina Proteica , Retina/patología , Epitelio Pigmentado de la Retina/patologíaRESUMEN
BACKGROUND: Age-related changes in the retina are often accompanied by visual impairment but their mechanistic details remain poorly understood. METHODOLOGY: Proteomic studies were pursued toward a better molecular understanding of retinal pigment epithelium (RPE) aging mechanisms. RPE cells were isolated from young adults (3-4 month-old) and old (24-25 month-old) F344BN rats, and separated into subcellular fractions containing apical microvilli (MV) and RPE cell bodies (CB) lacking their apical microvilli. Proteins were extracted in detergent, separated by SDS-PAGE, digested in situ with trypsin and analyzed by LC MS/MS. Select proteins detected in young and old rat RPE were further studied using immunofluorescence and Western blot analysis. PRINCIPAL FINDINGS: A total of 356 proteins were identified in RPE MV from young and 378 in RPE MV from old rats, 48% of which were common to each age group. A total of 897 proteins were identified in RPE CB from young rats and 675 in old CB, 56% of which were common to each age group. Several of the identified proteins, including proteins involved in response to oxidative stress, displayed both quantitative and qualitative changes in overall abundance during RPE aging. Numerous proteins were identified for the first time in the RPE. One such protein, collectrin, was localized to the apical membrane of apical brush border of proximal tubules where it likely regulates several amino acid transporters. Elsewhere, collectrin is involved in pancreatic ß cell proliferation and insulin secretion. In the RPE, collectrin expression was significantly modulated during RPE aging. Another age-regulated, newly described protein was DJ-1, a protein extensively studied in brain where oxidative stress-related functions have been described. CONCLUSIONS/SIGNIFICANCE: The data presented here reveals specific changes in the RPE during aging, providing the first protein database of RPE aging, which will facilitate future studies of age-related retinal diseases.
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Envejecimiento/fisiología , Regulación de la Expresión Génica/fisiología , Proteínas del Tejido Nervioso/metabolismo , Epitelio Pigmentado de la Retina/fisiología , Animales , Western Blotting , Cromatografía Liquida , Electroforesis en Gel de Poliacrilamida , Técnica del Anticuerpo Fluorescente , Inmunohistoquímica , Glicoproteínas de Membrana/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Proteínas del Tejido Nervioso/aislamiento & purificación , Proteína Desglicasa DJ-1 , Ratas , Epitelio Pigmentado de la Retina/metabolismo , Espectrometría de Masas en TándemRESUMEN
PURPOSE: Here the authors describe the structural features of the retina and retinal pigment epithelium (RPE) in postmortem donor eyes of a 56-year-old patient with a homozygous missense RPE65 mutation (Ala132Thr) and correlate the pathology with the patient's visual function last measured at age 51. METHODS: Eyes were enucleated within 13.5 hours after death. Representative areas from the macula and periphery were processed for light and electron microscopy. Immunofluorescence was used to localize the distribution of RPE65, rhodopsin, and cone arrestin. The autofluorescence in the RPE was compared with that of two normal eyes from age-similar donors. RESULTS: Histologic examination revealed the loss of rods and cones across most areas of the retina, attenuated retinal vessels, and RPE thinning in both eyes. A small number of highly disorganized cones were present in the macula that showed simultaneous labeling with cone arrestin and red/green or blue opsin. RPE65 immunoreactivity and RPE autofluorescence were reduced compared with control eyes in all areas studied. Rhodopsin labeling was observed in rods in the far periphery. The optic nerve showed a reduced number of axons. CONCLUSIONS: The clinical findings of reduced visual acuity, constricted fields, and reduced electroretinograms (ERGs) 5 years before death correlated with the small number of cones present in the macula and the extensive loss of photoreceptors in the periphery. The absence of autofluorescence in the RPE suggests that photoreceptor cells were probably missing across the retina for extended periods of time. Possible mechanisms that could lead to photoreceptor cell death are discussed.
Asunto(s)
Proteínas Portadoras/genética , Proteínas del Ojo/genética , Mutación Missense , Degeneración Retiniana/genética , Degeneración Retiniana/patología , cis-trans-Isomerasas/genética , Arrestina/metabolismo , Lámina Basal de la Coroides/metabolismo , Lámina Basal de la Coroides/ultraestructura , Proteínas Portadoras/metabolismo , Electrorretinografía , Proteínas del Ojo/metabolismo , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Masculino , Persona de Mediana Edad , Nervio Óptico/patología , Células Fotorreceptoras de Vertebrados/metabolismo , Células Fotorreceptoras de Vertebrados/ultraestructura , Degeneración Retiniana/metabolismo , Epitelio Pigmentado de la Retina/metabolismo , Epitelio Pigmentado de la Retina/ultraestructura , Rodopsina/metabolismo , Trastornos de la Visión/genética , Trastornos de la Visión/fisiopatología , Agudeza Visual/fisiología , Campos Visuales/fisiologíaRESUMEN
Mutations in genes expressed in the retinal pigment epithelium (RPE) underlie a number of human inherited retinal disorders that manifest with photoreceptor degeneration. Because light-evoked responses of the RPE are generated secondary to rod photoreceptor activity, RPE response reductions observed in human patients or animal models may simply reflect decreased photoreceptor input. The purpose of this study was to define how the electrophysiological characteristics of the RPE change when the complement of rod photoreceptors is decreased. To measure RPE function, we used an electroretinogram (dc-ERG)-based technique. We studied a slowly progressive mouse model of photoreceptor degeneration (Prph(Rd2/+)), which was crossed onto a Nyx(nob) background to eliminate the b-wave and most other postreceptoral ERG components. On this background, Prph(Rd2/+) mice display characteristic reductions in a-wave amplitude, which parallel those in slow PIII amplitude and the loss of rod photoreceptors. At 2 and 4 mo of age, the amplitude of each dc-ERG component (c-wave, fast oscillation, light peak, and off response) was larger in Prph(Rd2/+) mice than predicted by rod photoreceptor activity (Rm(P3)) or anatomical analysis. At 4 mo of age, the RPE in Prph(Rd2/+) mice showed several structural abnormalities including vacuoles and swollen, hypertrophic cells. These data demonstrate that insights into RPE function can be gained despite a loss of photoreceptors and structural changes in RPE cells and, moreover, that RPE function can be evaluated in a broader range of mouse models of human retinal disease.
Asunto(s)
Luz , Epitelio Pigmentado de la Retina/efectos de la radiación , Células Fotorreceptoras Retinianas Bastones/efectos de la radiación , Envejecimiento/fisiología , Algoritmos , Alelos , Animales , Electrorretinografía , Inmunohistoquímica , Proteínas de Filamentos Intermediarios/genética , Glicoproteínas de Membrana/genética , Ratones , Proteínas del Tejido Nervioso/genética , Periferinas , Degeneración Retiniana/genética , Degeneración Retiniana/patología , Epitelio Pigmentado de la Retina/patología , Células Fotorreceptoras Retinianas Bastones/patologíaRESUMEN
PURPOSE: To define the retinal pathology in an 88-year-old male affected with Goldmann-Favre syndrome with a 2 bp 5' A>C splice site mutation in the NR2E3 gene. METHODS: Retinal tissue from the macula and periphery was processed for immunohistochemistry. Perimacular retina was processed for transmission electron microscopy. Cryosections were studied by indirect immunofluorescence, using well-characterized antibodies to rhodopsin, cone cytoplasm, and cone opsins. The affected donor eye was compared to a postmortem matched normal eye. RESULTS: The retina was highly disorganized without laminar organization. The RPE was discontinuous in some perimacular regions. Large (>1 mm) spherical electrondense melanosomes were observed in the RPE and choroid by TEM. Rods were virtually absent in the affected retina. Cones were present in the macula, but were mostly absent from the retinal periphery. In addition, cone rosettes were observed in the perimacular area. Both red/green and blue cone opsins were distributed along the entire cellular expanse of the cone photoreceptors in the affected eye, but were restricted to the cone outer segments in the control retina. CONCLUSIONS: The histological data obtained from the retina of an elderly male patient with Goldmann-Favre syndrome showed an absence of rods and abnormal distribution of red/green and blue cone opsins.
Asunto(s)
Ceguera Nocturna/patología , Retina/patología , Degeneración Retiniana/patología , Anciano , Anciano de 80 o más Años , Arrestina/metabolismo , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Masculino , Ceguera Nocturna/genética , Ceguera Nocturna/metabolismo , Opsinas/metabolismo , Receptores Nucleares Huérfanos/genética , Retina/metabolismo , Degeneración Retiniana/genética , Degeneración Retiniana/metabolismo , Epitelio Pigmentado de la Retina/ultraestructura , Rodopsina/metabolismo , SíndromeRESUMEN
PURPOSE: To define the retinal pathology in a 91 year-old affected matriarch of a three-generation choroideremia family with multiple manifesting carriers. METHODS: Tissue from three different retinal areas was processed for immunohistochemistry. The macular area was processed for transmission electron microscopy. Cryosections were studied by indirect immunofluorescence, using well-characterized antibodies to cone cytoplasm, rhodopsin and cone opsins. The affected donor eyes were compared to a postmortem matched normal eye. RESULTS: The retina displayed areas of severe degeneration, with no photoreceptor outer segments, photoreceptor nuclear atrophy, and atrophy of the inner retina. Other retinal areas were near to normal. The RPE was severely degenerated, with thinning, pigment clumping and sub-epithelial debris deposition in all the areas examined. The choroid displayed depigmentation. Labeling with cone opsin antibodies revealed that cones were drastically affected: blue opsin was almost completely absent, while red/green opsins were distributed along the entire plasma membrane of the cell. Rhodopsin was also distributed along the entire rod plasma membrane. Ultrastructural analysis of the affected macula revealed the absence of RPE apical microvilli and basal infoldings. Instead, RPE's basal surface and choroid displayed the presence of banded fibers composed of clumps of wide-spacing collagen. Bruch's membrane was filled with vesicular structures, some smooth and others with bristle-like projections. CONCLUSIONS: The histological data suggests that the clinical manifestation in this donor is related to degenerative changes in the retina, RPE, and choroid.