scholarly journals Suppressor of Cytokine Signaling 2 Regulates Retinal Pigment Epithelium Metabolism by Enhancing Autophagy

2021 ◽  
Vol 15 ◽  
Author(s):  
Xi-Yuan Liu ◽  
Rui Lu ◽  
Jing Chen ◽  
Jie Wang ◽  
Hong-Mei Qian ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Metabolic Regulation ◽  
Glycogen Synthase ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Cytokine Signaling ◽  
Suppressor Of Cytokine Signaling ◽  
Rpe Cells ◽  
Age Related

Retinal pigment epithelium (RPE) serves critical functions in maintaining retinal homeostasis. An important function of RPE is to degrade the photoreceptor outer segment fragments daily to maintain photoreceptor function and longevity throughout life. An impairment of RPE functions such as metabolic regulation leads to the development of age-related macular degeneration (AMD) and inherited retinal degenerative diseases. As substrate recognition subunit of a ubiquitin ligase complex, suppressor of cytokine signaling 2 (SOCS2) specifically binds to the substrates for ubiquitination and negatively regulates growth hormone signaling. Herein, we explore the role of SOCS2 in the metabolic regulation of autophagy in the RPE cells. SOCS2 knockout mice exhibited the irregular morphological deposits between the RPE and Bruch’s membrane. Both in vivo and in vitro experiments showed that RPE cells lacking SOCS2 displayed impaired autophagy, which could be recovered by re-expressing SOCS2. SOCS2 recognizes the ubiquitylated proteins and participates in the formation of autolysosome by binding with autophagy receptors and lysosome-associated membrane protein2 (LAMP-2), thereby regulating the phosphorylation of glycogen synthase kinase 3β (GSK3β) and mammalian target of rapamycin (mTOR) during the autophagy process. Our results imply that SOCS2 participates in ubiquitin-autophagy-lysosomal pathway and enhances autophagy by regulating GSK3β and mTOR. This study provides a potential therapeutic target for AMD.

scholarly journals Development-related mitochondrial properties of retinal pigment epithelium cells derived from hEROs

2021 ◽  
Vol 14 (8) ◽  
pp. 1138-1150
Author(s):  
Hao-Jue Xu ◽  
◽  
Ting Zou ◽  
Zheng-Qin Yin ◽  
◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Embryonic Stem ◽  
Age Related Macular Degeneration ◽  
Level Energy ◽  
Rpe Cells ◽  
Age Related ◽  
High Level

AIM: To explore the temporal mitochondrial characteristics of retinal pigment epithelium (RPE) cells obtained from human embryonic stem cells (hESC)-derived retinal organoids (hEROs-RPE), to verify the optimal period for using hEROs-RPE as donor cells from the aspect of mitochondria and to optimize RPE cell-based therapeutic strategies for age-related macular degeneration (AMD). METHODS: RPE cells were obtained from hEROs and from spontaneous differentiation (SD-RPE). The mitochondrial characteristics were analyzed every 20d from day 60 to 160. Mitochondrial quantity was measured by MitoTracker Green staining. Transmission electron microscopy (TEM) was adopted to assess the morphological features of the mitochondria, including their distribution, length, and cristae. Mitochondrial membrane potentials (MMPs) were determined by JC-1 staining and evaluated by flow cytometry, reactive oxygen species (ROS) levels were evaluated by flow cytometry, and adenosine triphosphate (ATP) levels were measured by a luminometer. Differences between two groups were analyzed by the independent-samples t-test, and comparisons among multiple groups were made using one-way ANOVA or Kruskal-Wallis H test when equal variance was not assumed. RESULTS: hEROs-RPE and SD-RPE cells from day 60 to 160 were successfully differentiated from hESCs and expressed RPE markers (Pax6, MITF, Bestrophin-1, RPE65, Cralbp). RPE features, including a cobblestone-like morphology with tight junctions (ZO-1), pigments and microvilli, were also observed in both hEROs-RPE and SD-RPE cells. The mitochondrial quantities of hEROs-RPE and SD-RPE cells both peaked at day 80. However, the cristae of hEROs-RPE mitochondria were less mature and abundant than those of SD-RPE mitochondria at day 80, with hEROs-RPE mitochondria becoming mature at day 100. Both hEROs-RPE and SD-RPE cells showed low ROS levels from day 100 to 140 and maintained a normal MMP during this period. However, hEROs-RPE mitochondria maintained a longer time to produce high levels of ATP (from day 120 to 140) than SD-RPE cells (only day 120). CONCLUSION: hEROs-RPE mitochondria develop more slowly and maintain a longer time to supply high-level energy than SD-RPE mitochondria. From the mitochondrial perspective, hEROs-RPE cells from day 100 to 140 are an optimal cell source for treating AMD.

scholarly journals Transcriptomic and proteomic retinal pigment epithelium signatures of age-related macular degeneration.

2021 ◽  
Author(s):  
Anne Senabouth ◽  
Maciej Daniszewski ◽  
Grace Lidgerwood ◽  
Helena Liang ◽  
Damian Hernandez ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Macular Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Disease Status ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Rpe Cells ◽  
Age Related ◽  
Mitochondrial Functions

Induced pluripotent stem cells generated from patients with geographic atrophy as well as healthy individuals were differentiated to retinal pigment epithelium (RPE) cells. By integrating transcriptional profiles of 127,659 RPE cells generated from 43 individuals with geographic atrophy and 36 controls with genotype data, we identified 439 expression Quantitative Trait (eQTL) loci in cis that were associated with disease status and specific to subpopulations of RPE cells. We identified loci linked to two genes with known associations with geographic atrophy - PILRB and PRPH2, in addition to 43 genes with significant genotype x disease interactions that are candidates for novel genetic associations for geographic atrophy. On a transcriptome-only level, we identified molecular pathways significantly upregulated in geographic atrophy-RPE including in extracellular cellular matrix reorganisation, neurodegeneration, and mitochondrial functions. We subsequently implemented a large-scale proteomics analysis, confirming modification in proteins associated with these pathways. We also identified six significant protein (p) QTL that regulate protein expression in the RPE cells and in geographic atrophy - two of which share variants with cis-eQTL. Transcriptome-wide association analysis identified genes at loci previously associated with age-related macular degeneration. Further analysis conditional on disease status, implicated statistically significant RPE-specific eQTL. This study uncovers important differences in RPE homeostasis associated with geographic atrophy.

scholarly journals mTOR activity is essential for retinal pigment epithelium regeneration in zebrafish

2021 ◽  
Author(s):  
Jeff Gross ◽  
Fangfang Lu ◽  
Lyndsay Leach
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Mtor Pathway ◽  
Age Related Macular Degeneration ◽  
Model Systems ◽  
Rpe Cells ◽  
Genetic Ablation ◽  
Age Related ◽  
Mtor Activity

The retinal pigment epithelium (RPE) plays numerous critical roles in maintaining vision and this is underscored by the prevalence of degenerative blinding diseases like age-related macular degeneration (AMD), in which visual impairment is caused by progressive loss of RPE cells. In contrast to mammals, zebrafish possess the ability to intrinsically regenerate a functional RPE layer after severe injury. The molecular underpinnings of this regenerative process remain largely unknown yet hold tremendous potential for developing treatment strategies to stimulate endogenous regeneration in the human eye.  In this study, we demonstrate that the mTOR pathway is activated in RPE cells post-genetic ablation. Pharmacological and genetic inhibition of mTOR activity impaired RPE regeneration, while mTOR activation enhanced RPE recovery post-injury, demonstrating that mTOR activity is necessary and sufficient for RPE regeneration in zebrafish. RNA-seq of RPE isolated from mTOR-inhibited larvae identified a number of genes and pathways dependent on mTOR activity at early and late stages of regeneration; amongst these were components of the immune system, which is emerging as a key regulator of regenerative responses across various tissue and model systems.  Our results identify crosstalk between macrophages/microglia and the RPE, wherein mTOR activity in the RPE is required for recruitment of macrophages/microglia to the injury site. In turn, these macrophages/microglia reinforce mTOR activity in regenerating RPE cells. Interestingly, the function of macrophages/microglia in maintaining mTOR activity in the RPE appeared to be inflammation-independent. Taken together, these data identify mTOR activity as a key regulator of RPE regeneration and link the mTOR pathway to immune responses in facilitating RPE regeneration.

scholarly journals Nanoceria Particles Are an Eligible Candidate to Prevent Age-Related Macular Degeneration by Inhibiting Retinal Pigment Epithelium Cell Death and Autophagy Alterations

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1617 ◽  
Author(s):  
Annamaria Tisi ◽  
Vincenzo Flati ◽  
Simona Delle Monache ◽  
Luca Lozzi ◽  
Maurizio Passacantando ◽  
...  
Keyword(s):  
Cell Death ◽  
Retinal Pigment Epithelium ◽  
Macular Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Cellular Damage ◽  
Mesenchymal Transition ◽  
Rpe Cells ◽  
Age Related

Retinal pigment epithelium (RPE) dysfunction and degeneration underlie the development of age-related macular degeneration (AMD), which is the leading cause of blindness worldwide. In this study, we investigated whether cerium oxide nanoparticles (CeO2-NPs or nanoceria), which are anti-oxidant agents with auto-regenerative properties, are able to preserve the RPE. On ARPE-19 cells, we found that CeO2-NPs promoted cell viability against H2O2–induced cellular damage. For the in vivo studies, we used a rat model of acute light damage (LD), which mimics many features of AMD. CeO2-NPs intravitreally injected three days before LD prevented RPE cell death and degeneration and nanoceria labelled with fluorescein were found localized in the cytoplasm of RPE cells. CeO2-NPs inhibited epithelial-mesenchymal transition of RPE cells and modulated autophagy by the down-regulation of LC3B-II and p62. Moreover, the treatment inhibited nuclear localization of LC3B. Taken together, our study demonstrates that CeO2-NPs represent an eligible candidate to counteract RPE degeneration and, therefore, a powerful therapy for AMD.

scholarly journals iPSC-Derived Retinal Pigment Epithelium Allografts Do Not Elicit Detrimental Effects in Rats: A Follow-Up Study

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Peter D. Westenskow ◽  
Felicitas Bucher ◽  
Stephen Bravo ◽  
Toshihide Kurihara ◽  
Daniel Feitelberg ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Subretinal Space ◽  
Rpe Cells ◽  
Follow Up Study ◽  
Age Related ◽  
Photoreceptor Neurons

Phototransduction is accomplished in the retina by photoreceptor neurons and retinal pigment epithelium (RPE) cells. Photoreceptors rely heavily on the RPE, and death or dysfunction of RPE is characteristic of age-related macular degeneration (AMD), a very common neurodegenerative disease for which no cure exists. RPE replacement is a promising therapeutic intervention for AMD, and large numbers of RPE cells can be generated from pluripotent stem cells. However, questions persist regarding iPSC-derived RPE (iPS-RPE) viability, immunogenicity, and tumorigenesis potential. We showed previously that iPS-RPE prevent photoreceptor atrophy in dystrophic rats up until 24 weeks after implantation. In this follow-up study, we longitudinally monitored thesame implanted iPS-RPE, in the same animals. We observed no gross abnormalities in the eyes, livers, spleens, brains, and blood in aging rats with iPSC-RPE grafts. iPS-RPE cells that integrated into the subretinal space outlived the photoreceptors and survived for as long as 2 1/2 years while nonintegrating RPE cells were ingested by host macrophages. Both populations could be distinguished using immunohistochemistry and electron microscopy. iPSC-RPE could be isolated from the grafts and maintained in culture; these cells also phagocytosed isolated photoreceptor outer segments. We conclude that iPS-RPE grafts remain viable and do not induce any obvious associated pathological changes.

scholarly journals Regeneration of the zebrafish retinal pigment epithelium after widespread genetic ablation

2018 ◽  
Author(s):  
Nicholas J. Hanovice ◽  
Lyndsay L. Leach ◽  
Kayleigh Slater ◽  
Ana E. Gabriel ◽  
Dwight Romanovicz ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Wnt Signaling ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Rpe Cells ◽  
Genetic Ablation ◽  
Age Related ◽  
First Time

ABSTRACTThe retinal pigment epithelium (RPE) is a specialized monolayer of pigmented cells within the eye that is critical for maintaining visual system function. Diseases affecting the RPE have dire consequences for vision, and the most prevalent of these is atrophic (dry) age-related macular degeneration (AMD), which is thought to result from RPE dysfunction and degeneration. An intriguing possibility for treating RPE degenerative diseases like atrophic AMD is the stimulation of endogenous RPE regeneration; however, very little is known about the mechanisms driving successful RPE regeneration in vivo. Here, we developed a zebrafish transgenic model (rpe65a:nfsB-GFP) that enabled ablation of large swathes of mature RPE. RPE ablation resulted in rapid RPE degeneration, as well as degeneration of Bruch’s membrane and underlying photoreceptors. Using this model, we demonstrate for the first time that larval and adult zebrafish are capable of regenerating a functional RPE monolayer after RPE ablation. Regenerated RPE cells first appear at the periphery of the RPE, and regeneration proceeds in a peripheral-to-central fashion. RPE ablation elicits a robust proliferative response in the remaining RPE. Subsequently, proliferative cells move into the injury site and differentiate into RPE. BrdU pulse-chase analyses demonstrate that the regenerated RPE is likely derived from remaining peripheral RPE cells. Pharmacological inhibition of Wnt signaling significantly reduces cell proliferation in the RPE and delays overall RPE recovery. These data demonstrate that the zebrafish RPE possesses a robust capacity for regeneration and highlight a potential mechanism through which endogenous RPE regenerate in vivo.SIGNIFICANCE STATEMENTDiseases resulting in RPE degeneration are among the leading causes of blindness worldwide, and no therapy exists that can replace RPE or restore lost vision. One intriguing possibility is the development of therapies focused on stimulating endogenous RPE regeneration. For this to be possible, we must first gain a deeper understanding of the mechanisms underlying RPE regeneration. Here, we ablate mature RPE in zebrafish and demonstrate that zebrafish regenerate RPE after widespread injury. Injury-adjacent RPE proliferate and regenerate RPE, suggesting that they are the source of regenerated tissue. Finally, we demonstrate that Wnt signaling is required for RPE regeneration. These findings establish an in vivo model through which the molecular and cellular underpinnings of RPE regeneration can be further characterized.

scholarly journals A2E induces the transactivation of RARs, PPARs and RXRs and its effects are counteracted by norbixin in retinal pigment epithelium cells in vitro

2020 ◽  
Author(s):  
Valérie Fontaine ◽  
Mylène Fournié ◽  
Elodie Monteiro ◽  
Thinhinane Boumedine ◽  
Christine Balducci ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Mrna Expression ◽  
Biological Effects ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
B Cell Lymphoma ◽  
Age Related Macular Degeneration ◽  
Light Illumination ◽  
Rpe Cells ◽  
Age Related

ABSTRACTN-retinylidene-N-retinylethanolamine (A2E) plays a central role in age-related macular degeneration (AMD) by inducing apoptosis, angiogenesis and inflammation. It has been proposed that A2E effects are mediated at least partly via the retinoic acid receptor (RAR)-α. Here we show that A2E binds and transactivates not only RARs, but also peroxisome proliferator-activated receptors (PPARs) and retinoid X receptors (RXRs). Norbixin, which protects retinal pigment epithelium (RPE) cells against apoptosis induced by combined blue light illumination and A2E exposure, is also a ligand of these nuclear receptors (NRs) but does not induce their transactivation. Norbixin inhibits RXRs and PPARs but enhances RARs transactivation induced by A2E. Norbixin also inhibits PPAR-γ transactivation induced by its high affinity ligand troglitazone. Photoprotection of RPE cells by norbixin correlates with maintained levels of the antiapoptotic B-cell lymphoma 2 (Bcl2) protein. Moreover, norbixin reduces protein kinase B (AKT) phosphorylation, NF-κB and activator protein 1 (AP-1) transactivation, and the mRNA expression of the inflammatory interleukins (IL) 6 and 8 and of vascular endothelial growth factor (VEGF) that are enhanced by A2E. By contrast, norbixin increases matrix metalloproteinase 9 (MMP9) and C-C motif chemokine ligand 2 (CCL2) mRNA expression but has neither effect on extracellular signal-regulated kinase (ERK) phosphorylation, nor on IL-18 mRNA expression in response to A2E. Altogether, we show for the first time that A2E deleterious biological effects appear to be mediated through RARs, PPARs and RXRs. Moreover, we report that the modulation of these NRs by norbixin may open new avenues for the treatment of AMD.

In Vivo Multimodal Retinal Imaging Correlates With Granular-specific Changes in the Organelles of Retinal Pigment Epithelium of a Murine Model of Stargardt Disease

2021 ◽  
Author(s):  
Ratheesh K. Meleppat ◽  
Kaitryn E. Ronning ◽  
Sarah J. Karlen ◽  
Marie E. Burns ◽  
Edward N. Pugh ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Ex Vivo ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Stargardt Disease ◽  
Rpe Cells ◽  
Age Related ◽  
Lipofuscin Granules

Abstract Melanosomes, lipofuscin, and melanolipofuscin are the three principal types of granular pigmented organelles found in the retinal pigment epithelium (RPE) cells. Changes in the density of melanosomes and lipofuscin granules in RPE cells are considered hallmarks of various retinal diseases, including Stargardt disease and age-related macular degeneration (AMD). Herein, we report the potential of an in vivo multimodal imaging technique based on directional back-scattering and short-wavelength fundus autofluorescence (SW-FAF) to study the disease-related changes in the density of melanosomes and lipofuscin granules in RPE cells. Changes in the concentration of these granules in Abca4-/- mice (a model of Stargardt disease) relative to age-matched wild-type (WT) controls were investigated. Directional optical coherence tomography (dOCT) was used to assess the melanosome density in vivo, whereas the AF images and emission spectra acquired with a spectrometer-integrated scanning laser ophthalmoscope (SLO) were used to characterize the lipofuscin and melanolipofuscin granules in the same RPE region. Subcellular-resolution ex vivo imaging using confocal fluorescence microscopy and electron microscopy was performed on the same tissue region to visualize and quantify melanosomes, lipofuscin, and melanolipofuscin granules. Comparisons between in vivo and ex vivo results confirmed an increased concentration of lipofuscin granules and decreased number of melanosomes in the RPE of Abca4-/- mice and provided an explanation for the differences in fluorescence and directionality of RPE scattering observed in vivo in the two mouse strains.

scholarly journals Human Amniotic Epithelial Stem Cell-Derived Retinal Pigment Epithelium Cells Repair Retinal Degeneration

2021 ◽  
Vol 9 ◽  
Author(s):  
Jinying Li ◽  
Chen Qiu ◽  
Yang Wei ◽  
Weixin Yuan ◽  
Jia Liu ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Retinal Degeneration ◽  
Mhc Class Ii ◽  
Trichostatin A ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Epithelial Stem Cells ◽  
Rpe Cells ◽  
Age Related

Age-related macular degeneration (AMD), featured with dysfunction and loss of retinal pigment epithelium (RPE), is lacking efficient therapeutic approaches. According to our previous studies, human amniotic epithelial stem cells (hAESCs) may serve as a potential seed cell source of RPE cells for therapy because they have no ethical concerns, no tumorigenicity, and little immunogenicity. Herein, trichostatin A and nicotinamide can direct hAESCs differentiation into RPE like cells. The differentiated cells display the morphology, marker expression and cellular function of the native RPE cells, and noticeably express little MHC class II antigens and high level of HLA-G. Moreover, visual function and retinal structure of Royal College of Surgeon (RCS) rats, a classical animal model of retinal degeneration, were rescued after subretinal transplantation with the hAESCs-derived RPE like cells. Our study possibly makes some contribution to the resource of functional RPE cells for cell therapy. Subretinal transplantation of hAESCs-RPE could be an optional therapeutic strategy for retinal degeneration diseases.

scholarly journals Histological Characterization of the Dicer1 Mutant Zebrafish Retina

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Saeed Akhtar ◽  
Sarita Rani Patnaik ◽  
Rakesh Kotapati Raghupathy ◽  
Turki M. Al-Mubrad ◽  
John A. Craft ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Developmental Stages ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Critical Role ◽  
Age Related Macular Degeneration ◽  
Control Fish ◽  
Rnase Iii ◽  
Rpe Cells ◽  
Age Related

DICER1, a multidomain RNase III endoribonuclease, plays a critical role in microRNA (miRNA) and RNA-interference (RNAi) functional pathways. Loss ofDicer1affects different developmental processes. Dicer1 is essential for retinal development and maintenance. DICER1 was recently shown to have another function of silencing the toxicity ofAluRNAs in retinal pigment epithelium (RPE) cells, which are involved in the pathogenesis of age related macular degeneration. In this study, we characterized aDicer1mutant fish line, which carries a nonsense mutation (W1457Ter) induced by N-ethyl-N-nitrosourea mutagenesis. Zebrafish DICER1 protein is highly conserved in the evolution. Zebrafish Dicer1 is expressed at the earliest stages of zebrafish development and persists into late developmental stages; it is widely expressed in adult tissues. HomozygousDicer1mutant fish (DICER1W1457Ter/W1457Ter) have an arrest in early growth with significantly smaller eyes and are dead at 14–18 dpf. HeterozygousDicer1mutant fish have similar retinal structure to that of control fish; the retinal pigment epithelium (RPE) cells are normal with no sign of degeneration at the age of 20 months.

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