scholarly journals Antiangiogenic and Neurogenic Activities ofSleeping Beauty-Mediated PEDF-Transfected RPE CellsIn VitroandIn Vivo

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Sandra Johnen ◽  
Yassin Djalali-Talab ◽  
Olga Kazanskaya ◽  
Theresa Möller ◽  
Nina Harmening ◽  
...  
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Sleeping Beauty ◽  
Biologically Active ◽  
Age Related Macular Degeneration ◽  
Subretinal Space ◽  
Transfected Cells ◽  
Rpe Cells ◽  
Pigment Epithelial ◽  
Age Related

Pigment epithelium-derived factor (PEDF) is a potent multifunctional protein that inhibits angiogenesis and has neurogenic and neuroprotective properties. Since the wet form of age-related macular degeneration is characterized by choroidal neovascularization (CNV), PEDF would be an ideal candidate to inhibit CNV and support retinal pigment epithelial (RPE) cells. However, its short half-life has precluded its clinical use. To deliver PEDF to the subretinal space, we transfected RPE cells with thePEDFgene using theSleeping Beautytransposon system. Transfected cells expressed and secreted biologically active recombinant PEDF (rPEDF). In cultures of human umbilical vein endothelial cells, rPEDF reduced VEGF-induced cumulative sprouting by ≥47%, decreased migration by 77%, and increased rate of apoptosis at least 3.4 times. rPEDF induced neurite outgrowth in neuroblastoma cells and protected ganglion and photoreceptor cells in organotypic retinal cultures. In a rat model of CNV, subretinal transplantation of PEDF-transfected cells led to a reduction of the CNV area by 48% 14 days after transplantation and decreased clinical significant lesions by 55% and 40% after 7 and 14 days, respectively. We showed that transplantation of pigment epithelial cells overexpressingPEDFcan restore a permissive subretinal environment for RPE and photoreceptor maintenance, while inhibiting choroidal blood vessel growth.

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 Acadesine suppresses TNF-α induced complement component 3 (C3), in retinal pigment epithelial (RPE) cells

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244307
Author(s):  
Nikolaos E. Efstathiou ◽  
Giannis A. Moustafa ◽  
Daniel E. Maidana ◽  
Eleni K. Konstantinou ◽  
Shoji Notomi ◽  
...  
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Complement Component ◽  
Adenosine Kinase ◽  
Age Related Macular Degeneration ◽  
Dependent Manner ◽  
Rpe Cells ◽  
Age Related ◽  
Tnf Α ◽  
Complement Component 3

Rationale Age-related macular degeneration (AMD) is the most prevalent form of irreversible blindness in the developed world. Aging, inflammation and complement dysregulation affecting the retinal pigment epithelium (RPE), are considered significant contributors in its pathogenesis and several evidences have linked tumor necrosis factor alpha (TNF-α) and complement component 3 (C3) with AMD. Acadesine, an analog of AMP and an AMP-activated protein kinase (AMPK) activator, has been shown to have cytoprotective effects in human clinical trials as well as having anti-inflammatory and anti-vascular exudative effects in animals. The purpose of this study was to evaluate if acadesine is able to suppress TNF-α induced C3 in RPE cells. Methods ARPE-19 and human primary RPE cells were cultured and allowed to grow to confluence. TNF-α was used for C3 induction in the presence or absence of acadesine. Small molecule inhibitors and siRNA were used to determine if acadesine exerts its effect via the extracellular or intracellular pathway and to evaluate the importance of AMPK for these effects. The expression level of C3 was determined by immunoblot analysis. Results Acadesine suppresses TNF-α induced C3 in a dose dependent manner. When we utilized the adenosine receptor inhibitor dipyridamole (DPY) along with acadesine, acadesine’s effects were abolished, indicating the necessity of acadesine to enter the cell in order to exert it’s action. However, pretreatment with 5-iodotubericidin (5-Iodo), an adenosine kinase (AK) inhibitor, didn’t prevent acadesine from decreasing TNF-α induced C3 expression suggesting that acadesine does not exert its effect through AMP conversion and subsequent activation of AMPK. Consistent with this, knockdown of AMPK α catalytic subunit did not affect the inhibitory effect of acadesine on TNF-α upregulation of C3. Conclusions Our results suggest that acadesine suppresses TNF-α induced C3, likely through an AMPK-independent pathway, and could have potential use in complement over activation diseases.

scholarly journals PGC-1α Protects RPE Cells of the Aging Retina against Oxidative Stress-Induced Degeneration through the Regulation of Senescence and Mitochondrial Quality Control. The Significance for AMD Pathogenesis

2018 ◽  
Vol 19 (8) ◽  
pp. 2317 ◽  
Author(s):  
Kai Kaarniranta ◽  
Jakub Kajdanek ◽  
Jan Morawiec ◽  
Elzbieta Pawlowska ◽  
Janusz Blasiak
Keyword(s):  
Oxidative Stress ◽  
Cellular Senescence ◽  
Mitochondrial Biogenesis ◽  
Vision Loss ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Sirtuin 1 ◽  
Age Related Macular Degeneration ◽  
Rpe Cells ◽  
Age Related

PGC-1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) is a transcriptional coactivator of many genes involved in energy management and mitochondrial biogenesis. PGC-1α expression is associated with cellular senescence, organismal aging, and many age-related diseases, including AMD (age-related macular degeneration), an important global issue concerning vision loss. We and others have developed a model of AMD pathogenesis, in which stress-induced senescence of retinal pigment epithelium (RPE) cells leads to AMD-related pathological changes. PGC-1α can decrease oxidative stress, a key factor of AMD pathogenesis related to senescence, through upregulation of antioxidant enzymes and DNA damage response. PGC-1α is an important regulator of VEGF (vascular endothelial growth factor), which is targeted in the therapy of wet AMD, the most devastating form of AMD. Dysfunction of mitochondria induces cellular senescence associated with AMD pathogenesis. PGC-1α can improve mitochondrial biogenesis and negatively regulate senescence, although this function of PGC-1α in AMD needs further studies. Post-translational modifications of PGC-1α by AMPK (AMP kinase) and SIRT1 (sirtuin 1) are crucial for its activation and important in AMD pathogenesis.

scholarly journals Transcriptome-Wide Analysis of CXCR5 Deficient Retinal Pigment Epithelial (RPE) Cells Reveals Molecular Signatures of RPE Homeostasis

Biomedicines ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 147 ◽  
Author(s):  
Madhu Sudhana Saddala ◽  
Anton Lennikov ◽  
Anthony Mukwaya ◽  
Hu Huang
Keyword(s):  
Epithelial Mesenchymal Transition ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Enrichment Analysis ◽  
Age Related Macular Degeneration ◽  
Pathway Enrichment Analysis ◽  
Molecular Signatures ◽  
Mesenchymal Transition ◽  
Rpe Cells ◽  
Age Related

Age-related macular degeneration (AMD) is the most common cause of irreversible blindness in the elderly population. In our previous studies, we found that deficiency of CXCR5 causes AMD-like pathological phenotypes in mice, characterized by abnormalities and dysfunction of the retinal pigment epithelium (RPE) cells. The abnormalities included abnormal cellular shape and impaired barrier function. In the present study, primary RPE cells were derived separately from CXCR5 knockout (KO) mice and from C57BL6 wild type (WT). The isolated primary cells were cultured for several days, and then total RNA was isolated and used for library preparation, sequencing, and the resultant raw data analyzed. Relative to the WT, a total of 1392 differentially expressed genes (DEG) were identified. Gene ontology analysis showed various biological processes, cellular components, and molecular functions were enriched. Pathway enrichment analysis revealed several pathways, including the PI3K-Akt signaling, mTOR signaling, FoxO, focal adhesion, endocytosis, ubiquitin-mediated proteolysis, TNFα-NF-kB Signaling, adipogenesis genes, p53 signaling, Ras, autophagy, epithelial–mesenchymal transition (EMT), and mitochondrial pathway. This study explores molecular signatures associated with deficiency of CXCR5 in RPE cells. Many of these signatures are important for homeostasis of this tissue. The identified pathways and genes require further evaluation to better understand the pathophysiology of AMD.

scholarly journals Beyond AREDS Formulations, What Is Next for Intermediate Age-Related Macular Degeneration (iAMD) Treatment? Potential Benefits of Antioxidant and Anti-inflammatory Apocarotenoids as Neuroprotectors

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Serge Camelo ◽  
Mathilde Latil ◽  
Stanislas Veillet ◽  
Pierre J. Dilda ◽  
René Lafont
Keyword(s):  
Macular Degeneration ◽  
Light Exposure ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Developed Countries ◽  
Age Related Macular Degeneration ◽  
Crocus Sativus ◽  
Subretinal Space ◽  
Major Health Problem ◽  
Age Related

Age-related macular degeneration (AMD) is the commonest cause of severe visual loss and blindness in developed countries among individuals aged 60 and older. AMD slowly progresses from early AMD to intermediate AMD (iAMD) and ultimately late-stage AMD. Late AMD encompasses either neovascular AMD (nAMD) or geographic atrophy (GA). nAMD is defined by choroidal neovascularization (CNV) and hemorrhage in the subretinal space at the level of the macula. This induces a rapid visual impairment caused by the death of photoreceptor cells. Intravitreal injection of anti-vascular endothelial growth factor (VEGF) antibodies is the standard treatment of nAMD but adds to the burden of patient care. GA is characterized by slowly expanding photoreceptor, and retinal pigment epithelium (RPE) degeneration patches progressively leading to blindness. There is currently no therapy to cure GA. Late AMD continues to be an unmet medical need representing a major health problem with millions of patients worldwide. Oxidative stress and inflammation are recognized as some of the main risk factors to developing late AMD. The antioxidant formulation AREDS (Age-Related Eye Disease Studies), contains β-carotene, which has been replaced by lutein and zeaxanthin in AREDS2, are given to patients with iAMD but have a limited effect on the incidence of nAMD and GA. Thus, to avoid or slowdown the development of late stages of AMD (nAMD or GA), new therapies targeting iAMD are needed such as crocetin obtained through hydrolysis of crocin, an important component of saffron (Crocus sativus L.), and norbixin derived from bixin extracted from Bixa orellana seeds. We have shown that these apocarotenoids preserved more effectively RPE cells against apoptosis following blue light exposure in the presence of A2E than lutein and zeaxanthin. In this review, we will discuss the potential use of apocarotenoids to slowdown the progression of iAMD, to reduce the incidence of both forms of late AMD.

scholarly journals Oxidative stress-mediated TXNIP loss causes RPE dysfunction

2019 ◽  
Vol 51 (10) ◽  
pp. 1-13 ◽  
Author(s):  
Min Ji Cho ◽  
Sung-Jin Yoon ◽  
Wooil Kim ◽  
Jongjin Park ◽  
Jangwook Lee ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Function ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Common Factor ◽  
Age Related Macular Degeneration ◽  
Autophagic Flux ◽  
Blood Retinal Barrier ◽  
Rpe Cells ◽  
Age Related

Abstract The disruption of the retinal pigment epithelium (RPE), for example, through oxidative damage, is a common factor underlying age-related macular degeneration (AMD). Aberrant autophagy also contributes to AMD pathology, as autophagy maintains RPE homeostasis to ensure blood–retinal barrier (BRB) integrity and protect photoreceptors. Thioredoxin-interacting protein (TXNIP) promotes cellular oxidative stress by inhibiting thioredoxin reducing capacity and is in turn inversely regulated by reactive oxygen species levels; however, its role in oxidative stress-induced RPE cell dysfunction and the mechanistic link between TXNIP and autophagy are largely unknown. Here, we observed that TXNIP expression was rapidly downregulated in RPE cells under oxidative stress and that RPE cell proliferation was decreased. TXNIP knockdown demonstrated that the suppression of proliferation resulted from TXNIP depletion-induced autophagic flux, causing increased p53 activation via nuclear localization, which in turn enhanced AMPK phosphorylation and activation. Moreover, TXNIP downregulation further negatively impacted BRB integrity by disrupting RPE cell tight junctions and enhancing cell motility by phosphorylating, and thereby activating, Src kinase. Finally, we also revealed that TXNIP knockdown upregulated HIF-1α, leading to the enhanced secretion of VEGF from RPE cells and the stimulation of angiogenesis in cocultured human retinal microvascular endothelial cells. This suggests that the exposure of RPE cells to sustained oxidative stress may promote choroidal neovascularization, another AMD pathology. Together, these findings reveal three distinct mechanisms by which TXNIP downregulation disrupts RPE cell function and thereby exacerbates AMD pathogenesis. Accordingly, reinforcing or restoring BRB integrity by targeting TXNIP may serve as an effective therapeutic strategy for preventing or attenuating photoreceptor damage in AMD.

scholarly journals Protective Effect of Metformin against Hydrogen Peroxide-Induced Oxidative Damage in Human Retinal Pigment Epithelial (RPE) Cells by Enhancing Autophagy through Activation of AMPK Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Xia Zhao ◽  
Linlin Liu ◽  
Yizhou Jiang ◽  
Marta Silva ◽  
Xuechu Zhen ◽  
...  
Keyword(s):  
Oxidative Damage ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Protective Effects ◽  
Rpe Cells ◽  
Mitochondria Membrane Potential ◽  
Ampk Pathway ◽  
Age Related ◽  
Diabetes Drug

Age-related macular degeneration (AMD) is a leading cause of blindness with limited effective treatment. Although the pathogenesis of this disease is complex and not fully understood, the oxidative damage caused by excessive reactive oxygen species (ROS) in retinal pigment epithelium (RPE) has been considered as a major cause. Autophagy is essential for the degradation of cellular components damaged by ROS, and its dysregulation has been implicated in AMD pathogenesis. Therefore, strategies aiming to boost autophagy could be effective in protecting RPE cells from oxidative damage. Metformin is the first-line anti-type 2 diabetes drug and has been reported to stimulate autophagy in many tissues. We therefore hypothesized that metformin may be able to protect RPE cells against H2O2-induced oxidative damage by autophagy activation. In the present study, we found that metformin attenuated H2O2-induced cell viability loss, apoptosis, elevated ROS levels, and the collapse of the mitochondria membrane potential in D407 cells. Autophagy was stimulated by metformin, and inhibition of autophagy by 3-methyladenine (3-MA) and chloroquine (CQ) or knockdown of Beclin1 and LC3B blocked the protective effects of metformin. In addition, we showed that metformin could activate the AMPK pathway, whereas both pharmacological and genetic inhibitions of AMPK blocked the autophagy-stimulating and protective effects of metformin. Metformin conferred a similar protection against H2O2-induced oxidative damage in primary cultured human RPE cells. Taken together, these results demonstrate that metformin could protect RPE cells from H2O2-induced oxidative damage by stimulating autophagy via the activation of the AMPK pathway, supporting its potential use in the prevention and treatment of AMD.

scholarly journals Polypoidal Choroidal Vasculopathy

2021 ◽  
Vol 37 (2) ◽  
Author(s):  
Sana Nadeem
Keyword(s):  
Polypoidal Choroidal Vasculopathy ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Pigment Epithelial Detachment ◽  
Choroidal Neovascular Membrane ◽  
Hard Exudates ◽  
Pigment Epithelial ◽  
Age Related ◽  
Choroidal Vasculopathy

A 76-year-old, hypertensive lady, presented with a three year history of gradual decrease in vision in her right eye. Examination revealed a large, bullous, serous pigment epithelial detachment (PED) of right fovea, a choroidal neovascular membrane, clusters of hard exudates, drusen and surrounding, multifocal, small PEDs. The left eye showed a series of small PEDs mostly on the inferior macula, pigmentary disturbance of the retinal pigment epithelium and scant hard exudates. A diagnosis of Polypoidal choroidal vasculopathy was made. We decided to treat her with intravitreal Bevacizumab injections in her right eye. At 18 months of follow up, her PEDs had resolved and visual acuity had improved from 6/60 OD to 6/36. Key Words:  Polypoidal Choroidal Vasculopathy, Age Related Macular Degeneration, Pigment Epithelial Detachment, Choroidal Neovascular Membrane.

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.

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