scholarly journals Microglia dynamics in retinitis pigmentosa model: formation of fundus whitening and autofluorescence as an indicator of activity of retinal degeneration

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kenichi Makabe ◽  
Sunao Sugita ◽  
Michiko Mandai ◽  
Yoko Futatsugi ◽  
Masayo Takahashi
Keyword(s):  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Outer Nuclear Layer ◽  
Fundus Autofluorescence ◽  
Fundus Photography ◽  
Photoreceptor Outer Segments ◽  
Diagnostic Interpretation ◽  
Model Formation ◽  
Thinning Rate

Abstract In patients with retinitis pigmentosa (RP), color fundus photography and fundus autofluorescence (FAF) have been used to estimate the disease progression. To understand the origin and the diagnostic interpretation of the fundus color and FAF, we performed in vivo imaging of fundus color and FAF together with histological analyses of the retinal degeneration process using the RP model mice, rd10. FAF partly represented the accumulation of microglia in the photoreceptor outer segments. Fundus whitening suggested the presence of apoptotic cells, which spatiotemporally preceded increase in FAF. We observed two patterns of FAF localization, arcuate and diffuse, each indicating different pattern of apoptosis, wavy and diffuse, respectively. Diffuse pattern of apoptosis was suppressed in dark-raised rd10 mice, in which outer nuclear layer (ONL) loss was significantly suppressed. The occupancy of FAF correlated with the thinning rate of the ONL. Fractalkine, a microglia chemotactic factor, was detected in apoptotic photoreceptors, suggesting chemokine-induced recruitment of microglia into the ONL, which paralleled with accelerated ONL loss and increased FAF occupancy. Thus, we propose that the degree of photoreceptor apoptosis and the rate of ONL thinning in RP patients might be read from the fundus color and the FAF.

scholarly journals In vivo analysis of onset and progression of retinal degeneration in the Nr2e3rd7/rd7 mouse model of enhanced S-cone sensitivity syndrome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Giulia Venturini ◽  
Despina Kokona ◽  
Beatrice L. Steiner ◽  
Emanuele G. Bulla ◽  
Joel Jovanovic ◽  
...  
Keyword(s):  
Mouse Model ◽  
Retinal Degeneration ◽  
Apoptotic Cell ◽  
Outer Nuclear Layer ◽  
Fundus Photography ◽  
Opsin Expression ◽  
In Vivo Analysis ◽  
Cone Sensitivity ◽  
Inherited Retinal Degeneration

AbstractThe photoreceptor-specific nuclear receptor Nr2e3 is not expressed in Nr2e3rd7/rd7 mice, a mouse model of the recessively inherited retinal degeneration enhanced S-cone sensitivity syndrome (ESCS). We characterized in detail C57BL/6J Nr2e3rd7/rd7 mice in vivo by fundus photography, optical coherence tomography and fluorescein angiography and, post mortem, by histology and immunohistochemistry. White retinal spots and so-called ‘rosettes’ first appear at postnatal day (P) 12 in the dorsal retina and reach maximal expansion at P21. The highest density in ‘rosettes’ is observed within a region located between 100 and 350 µM from the optic nerve head. ‘Rosettes’ disappear between 9 to 12 months. Non-apoptotic cell death markers are detected during the slow photoreceptor degeneration, at a rate of an approximately 3% reduction of outer nuclear layer thickness per month, as observed from 7 to 31 months of age. In vivo analysis of Nr2e3rd7/rd7 Cx3cr1gfp/+ retinas identified microglial cells within ‘rosettes’ from P21 on. Subretinal macrophages were observed in vivo and by confocal microscopy earliest in 12-months-old Nr2e3rd7/rd7 retinas. At P21, S-opsin expression and the number of S-opsin expressing dorsal cones was increased. The dorso-ventral M-cone gradient was present in Nr2e3rd7/rd7 retinas, but M-opsin expression and M-opsin expressing cones were decreased. Retinal vasculature was normal.

scholarly journals Novel mutations in the 3-box motif of the BACK domain of KLHL7 associated with nonsyndromic autosomal dominant retinitis pigmentosa

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Jin Kyun Oh ◽  
Jose Ronaldo Lima de Carvalho ◽  
Young Joo Sun ◽  
Sara Ragi ◽  
Jing Yang ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Autosomal Dominant ◽  
Fundus Autofluorescence ◽  
Retinal Dystrophy ◽  
Protein Modeling ◽  
Fundus Photography ◽  
Imaging Biomarkers ◽  
Loss Of Function ◽  
Gene Panel Testing ◽  
Sd Oct

Abstract Background Mutations in the Kelch-like protein 7 (KLHL7) represent a recently described and, to date, poorly characterized etiology of inherited retinal dystrophy. Dominant mutations in KLHL7 are a cause of isolated, non-syndromic retinitis pigmentosa (RP). In contrast, recessive loss-of-function mutations are known to cause Crisponi or Bohring-Opitz like cold induced sweating syndrome-3 (BOS-3). In this study, the phenotype and progression of five unrelated patients with KLHL7 mediated autosomal dominant RP (adRP) are characterized. Clinical evaluation of these patients involved a complete ophthalmic exam, full-field electroretinography (ffERG), and imaging, including fundus photography, spectral domain optical coherence tomography (SD-OCT), short wavelength fundus autofluorescence (SW-AF), and near-infrared fundus autofluorescence (NIR-AF). Molecular diagnoses were performed using whole-exome sequencing or gene panel testing. Disease progression was monitored in three patients with available data for a mean follow up time of 4.5 ± 2.9 years. Protein modeling was performed for all variants found in this study in addition to those documented in the literature for recessive loss-of-function alleles causing Crisponi or Bohring-Opitz like cold-induced sweating syndrome. Results Genetic testing in three patients identified two novel variants within the 3-box motif of the BACK domain: c.472 T > C:p.(Cys158Arg) and c.433A > T:p.(Asn145Tyr). Clinical imaging demonstrated hyperautofluorescent ring formation on both SW-AF and NIR-AF in three patients, with diffuse peripheral and peripapillary atrophy seen in all but one case. SD-OCT demonstrated a phenotypic spectrum, from parafoveal atrophy of the outer retina with foveal sparing to widespread retinal thinning and loss of photoreceptors. Incidence of cystoid macular edema was high with four of five patients affected. Protein modeling of dominant alleles versus recessive loss-of-function alleles showed dominant alleles localized to the BTB and BACK domains while recessive alleles were found in the Kelch domain. Conclusions We report the phenotype in five patients with KLHL7 mediated adRP, two novel coding variants, and imaging biomarkers using SW-AF and NIR-AF. These findings may influence future gene-based therapies for adRP and pave the way for mechanistic studies that elucidate the pathogenesis of KLHL7-mediated RP.

scholarly journals Retinitis Pigmentosa Results in Neurodegeneration Concomitant With Neuroinflammation, Extracellular Matrix Disorganization and the Upregulation of Neuroprotective Pathways in Glial Cells and Neurons

2020 ◽  
Author(s):  
Christina B. Bielmeier ◽  
Saskia Roth ◽  
Sabrina I. Schmitt ◽  
Stefaniya K. Boneva ◽  
Anja Schlecht ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Molecular Mechanisms ◽  
Genetic Model ◽  
Immunofluorescent Staining ◽  
System Response ◽  
Photoreceptor Degeneration ◽  
The Impact

Abstract BackgroundHereditary retinal degenerations like retinitis pigmentosa (RP) are amongst the leading causes of blindness in younger patients. To enable in vivo investigation of cellular and molecular mechanisms responsible for photoreceptor cell death and to allow testing of therapeutic strategies that could prevent retinal degeneration, animal models have been created. Here, we in-depth characterized the transgenic VPP mouse model, a genetic model for autosomal dominant RP. MethodsWe examined the degree of photoreceptor degeneration and studied the impact of the VPP transgene-induced retinal degeneration on the transcriptome level of the retina using next generation RNA sequencing (RNASeq) analyses followed by weighted correlation network analysis (WGCNA). We furthermore identified cellular subpopulations responsible for some of the observed dysregulations using in situ hybridizations, immunofluorescent staining and 3D reconstruction. ResultsOne month-old VPP mice showed a significantly higher number of apoptotic photoreceptor cells that resulted in a significantly thinner ONL in three months-old VPP mice, concomitant with an increase in reactivity of microglia and Müller cells. By RNASeq analysis we identified 9,256 dysregulated genes and six significantly associated gene modules in the subsequently performed WGCNA. Gene ontology enrichment showed, amongst others, dysregulation of TGF-β regulated extracellular matrix organization, factors of the (ocular) immune system/response and apoptosis. ConclusionThe predominant effect pointed towards induction of neuroinflammation and the upregulation of neuroprotective pathways like TGF-β, G-protein activated and VEGF signaling that were significantly associated with the VPP transgene-induced photoreceptor degeneration. Thus, modulation of these processes might represent new therapeutic options to delay the degeneration of photoreceptors in diseases like RP.

Retinitis Pigmentosa; Epidemiology, Pathophysiology, and Classification

2021 ◽  
pp. 95-106
Keyword(s):  
Retinitis Pigmentosa ◽  
Pigment Epithelium ◽  
Fundus Autofluorescence ◽  
Visual Field Loss ◽  
Fundus Photography ◽  
Clinical Genetic ◽  
Comprehensive Overview ◽  
Cone Dysfunction ◽  
Hereditary Retinal Degeneration ◽  
Visual Acuity Loss

Retinitis pigmentosa (RP) is the most common hereditary retinal degeneration. It primarily affects rods and then cone photoreceptors. RP manifests with night blindness and concentric visual field loss, reflecting the dysfunction of rod photoreceptors. Central visual acuity loss occurs last period of disease due to cone dysfunction; otherwise, macula involvements like cystoid macular edema. Classically described fundus appearance of RP includes mottling and granularity of the retina pigment epithelium, bone spicule intraretinal pigmentation, attenuated retinal vessels, and optic disc head pallor. RP can be transmitted as Mendelian’s an autosomal dominant, autosomal recessive, or X-linked trait. Mitochondrial or digenic forms also rarely have been described. However, the sporadic or simplex form is the most commonly seen in the clinic. Recently great progress has been made in the identification of the causative genes. This review presents a comprehensive overview of the clinical, genetic, and fundus photography, optical coherence tomography, fundus autofluorescence, microperimetry dark adaptometer, and ocular electrophysiology characteristics of RP.

scholarly journals Light Stress-Induced Increase of Sphingosine 1-Phosphate in Photoreceptors and Its Relevance to Retinal Degeneration

2019 ◽  
Vol 20 (15) ◽  
pp. 3670 ◽  
Author(s):  
Ryo Terao ◽  
Megumi Honjo ◽  
Takashi Ueta ◽  
Hideru Obinata ◽  
Takashi Izumi ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Photoreceptor Cell ◽  
Light Exposure ◽  
Outer Nuclear Layer ◽  
Light Stress ◽  
Age Related Macular Degeneration ◽  
Lipid Mediator ◽  
Age Related ◽  
Sphingosine 1 Phosphate

Sphingosine 1-phosphate (S1P) is a potent lipid mediator that modulates inflammation and angiogenesis. In this study, we investigated the possible involvement of S1P in the pathology of light-induced retinal degeneration in vivo and in vitro. The intracellular S1P and sphingosine kinase (SphK) activity in a photoreceptor cell line (661W cells) was significantly increased by exposure to light. The enhancement of SphK1 expression was dependent on illumination, and all-trans-retinal significantly promoted SphK1 expression. S1P treatment reduced protein kinase B (Akt) phosphorylation and increased the protein expression of cleaved caspase-3, and induced photoreceptor cell apoptosis. In vivo, light exposure enhanced the expression of SphK1 in the outer segments of photoreceptors. Intravitreal injection of a SphK inhibitor significantly suppressed the thinning of the outer nuclear layer and ameliorated the attenuation of the amplitudes of a-waves and b-waves of electroretinograms during light-induced retinal degeneration. These findings imply that light exposure induces the synthesis of S1P in photoreceptors by upregulating SphK1, which is facilitated by all-trans-retinal, causing retinal degeneration. Inhibition of this enhancement may be a therapeutic target of outer retinal degeneration, including age-related macular degeneration.

scholarly journals Unique combination of clinical features in a large cohort of 100 patients with retinitis pigmentosa caused by FAM161A mutations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Avigail Beryozkin ◽  
Samer Khateb ◽  
Carlos Alberto Idrobo-Robalino ◽  
Muhammad Imran Khan ◽  
Frans P. M. Cremers ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Clinical Features ◽  
Outer Nuclear Layer ◽  
Single Gene ◽  
Fundus Autofluorescence ◽  
Severe Disease ◽  
Visual Fields ◽  
Future Application ◽  
Initial Symptom ◽  
Clinical Records

Abstract FAM161A mutations are the most common cause of autosomal recessive retinitis pigmentosa in the Israeli-Jewish population. We aimed to characterize the spectrum of FAM161A-associated phenotypes and identify characteristic clinical features. We identified 114 bi-allelic FAM161A patients and obtained clinical records of 100 of these patients. The most frequent initial symptom was night blindness. Best-corrected visual acuity was largely preserved through the first three decades of life and severely deteriorated during the 4th–5th decades. Most patients manifest moderate-high myopia. Visual fields were markedly constricted from early ages, but maintained for decades. Bone spicule-like pigmentary changes appeared relatively late, accompanied by nummular pigmentation. Full-field electroretinography responses were usually non-detectable at first testing. Fundus autofluorescence showed a hyper-autofluorescent ring around the fovea in all patients already at young ages. Macular ocular coherence tomography showed relative preservation of the outer nuclear layer and ellipsoid zone in the fovea, and frank cystoid macular changes were very rare. Interestingly, patients with a homozygous nonsense mutation manifest somewhat more severe disease. Our clinical analysis is one of the largest ever reported for RP caused by a single gene allowing identification of characteristic clinical features and may be relevant for future application of novel therapies.

scholarly journals Intravitreal Injection of Hydrogen Peroxide Induces Acute Retinal Degeneration, Apoptosis, and Oxidative Stress in Mice

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Bing Huang ◽  
Jia-Jian Liang ◽  
Xi Zhuang ◽  
Shao-Wan Chen ◽  
Tsz Kin Ng ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Ganglion Cell ◽  
Retinal Degeneration ◽  
Antioxidant Enzyme ◽  
Intravitreal Injection ◽  
Cell Apoptosis ◽  
Outer Nuclear Layer ◽  
Retinal Diseases

Purpose. Oxidative stress is a common pathological condition for multiple retinal diseases. Hydrogen peroxide (H2O2) has been applied as an oxidative stress inducer for the in vitro studies. Here, we report the in vivo effect of H2O2 exposure to the mouse retina and its underlying mechanism. Methods. The H2O2 or saline solution was intravitreally injected into the eyes of female C57BL/6J mice for two consecutive days. The retinal structure was evaluated by in vivo imaging using spectral domain optical coherence tomography (OCT) and validated by histological assessment as well as retinal marker expression. In addition, retinal stress, cell apoptosis, and antioxidant enzyme expression were also determined. Results. Retinal and outer nuclear layer thickness thinning was observed at days 7 and 14 by OCT imaging with the treatment of 10 μg H2O2, which was confirmed by the histopathological analysis. The expressions of photoreceptor (Rho, Rora, Rorb, and Rcvrn), bipolar cell (Chat and Calb2), and retinal pigment epithelial (Rpe65) markers were reduced in the H2O2-treated group, whereas the expression of retinal ganglion cell marker (Tubb3) was increased. TUNEL-positive cells were obviously found in the outer nuclear layer and inner nuclear layer of H2O2-treated mice but sparely found in the ganglion cell layer. Coherently, apoptotic gene expressions (Casp3, Casp9, Bax, and Parp8) were significantly increased in the retina with increasing dosages of H2O2, while Bcl2 expression was mildly decreased. In addition, the expressions of Gfap and antioxidant enzyme genes (Txn2, Sod2, and Gpx4) were significantly upregulated in the retina after the H2O2 treatment, compared to the vehicle control group. Conclusions. This study revealed that intravitreal injection of H2O2 induces acute retinal damage by increasing oxidative stress and cell apoptosis in the retina. This acute retinal degeneration mouse model could provide a platform for drug screening against oxidative stress and retinal diseases.

scholarly journals New insights into the molecular mechanism of rhodopsin retinitis pigmentosa from the biochemical and functional characterization of G90V, Y102H and I307N mutations

2022 ◽  
Vol 79 (1) ◽  
Author(s):  
María Guadalupe Herrera-Hernández ◽  
Neda Razzaghi ◽  
Pol Fernandez-Gonzalez ◽  
Laia Bosch-Presegué ◽  
Guillem Vila-Julià ◽  
...  
Keyword(s):  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Functional Characterization ◽  
In Vivo Studies ◽  
Therapeutic Approaches ◽  
The Subject ◽  
The Stability ◽  
Inherited Retinal Degeneration

AbstractMutations in the photoreceptor protein rhodopsin are known as one of the leading causes of retinal degeneration in humans. Two rhodopsin mutations, Y102H and I307N, obtained in chemically mutagenized mice, are currently the subject of increased interest as relevant models for studying the process of retinal degeneration in humans. Here, we report on the biochemical and functional characterization of the structural and functional alterations of these two rhodopsin mutants and we compare them with the G90V mutant previously analyzed, as a basis for a better understanding of in vivo studies. This mechanistic knowledge is fundamental to use it for developing novel therapeutic approaches for the treatment of inherited retinal degeneration in retinitis pigmentosa. We find that Y102H and I307N mutations affect the inactive–active equilibrium of the receptor. In this regard, the mutations reduce the stability of the inactive conformation but increase the stability of the active conformation. Furthermore, the initial rate of the functional activation of transducin, by the I307N mutant is reduced, but its kinetic profile shows an unusual increase with time suggesting a profound effect on the signal transduction process. This latter effect can be associated with a change in the flexibility of helix 7 and an indirect effect of the mutation on helix 8 and the C-terminal tail of rhodopsin, whose potential role in the functional activation of the receptor has been usually underestimated. In the case of the Y102H mutant, the observed changes can be associated with conformational alterations affecting the folding of the rhodopsin intradiscal domain, and its presumed involvement in the retinal binding process by the receptor.

scholarly journals Ift172 conditional knockout mice exhibit rapid retinal degeneration and protein trafficking defects

2017 ◽  
Author(s):  
Priya R Gupta ◽  
Nachiket Pendse ◽  
Scott H Greenwald ◽  
Mihoko Leon ◽  
Qin Liu ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Protein Trafficking ◽  
Primary Cilia ◽  
Molecular Mechanisms ◽  
Outer Nuclear Layer ◽  
Intraflagellar Transport ◽  
Conditional Knockout ◽  
Photoreceptor Outer Segments ◽  
Outer Segments ◽  
Trafficking Defects

AbstractIntraflagellar transport (IFT) is a bidirectional transport process that occurs along primary cilia and specialized sensory cilia, such as photoreceptor outer-segments. Genes coding for various IFT components are associated with ciliopathies. Mutations in IFT172 lead to diseases ranging from isolated retinal degeneration to severe syndromic ciliopathies. In this study, we created a mouse model of IFT172-associated retinal degeneration to investigate the ocular disease mechanism. We found that depletion of IFT172 in rod photoreceptors leads to a rapid degeneration of the retina, with severely reduced electroretinography responses by one month and complete outer-nuclear layer degeneration by two months. We investigated molecular mechanisms of degeneration and show that IFT172 protein reduction leads to mislocalization of specific photoreceptor outer-segments proteins (RHO, RP1, IFT139), aberrant light-driven translocation of alpha transducin and altered localization of glioma-associated oncogene family member 1 (GLI1). This murine model recapitulates the retinal phenotype seen in patients with IFT172-associated blindness and can be used for in vivo testing of ciliopathy therapies.

Retinitis pigmentosa and retinal degeneration in animals: a review

1984 ◽  
Vol 62 (6) ◽  
pp. 535-546 ◽  
Author(s):  
Yousef Matuk
Keyword(s):  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Human Disease ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Biochemical Basis ◽  
Photoreceptor Outer Segments ◽  
Rcs Rat ◽  
Retinoid Metabolism ◽  
Rcs Rats

Recent biochemical findings in the human disease, retinitis pigmentosa, and related retinal degenerative diseases in animals were reviewed and discussed. While the biochemical etiology of the human disease is not known, there are indications that retinal degeneration in the rd mouse and the Irish Setter dog are related to a deficiency in cGMP phosphodiesterase and the accumulation of cGMP in the photoreceptor outer segments. The biochemical basis of retinal degeneration in the Royal College of Surgeons (RCS) rat does not seem to be related to a defect in the metabolism of cGMP, but there are suggestions that a defect in retinoid metabolism may be involved. The possibility that the defect in RCS rats may involve receptors on the membranes of the cells of the retinal pigment epithelium or phagocytic markers on those of the rod outer segment disks was discussed.

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