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Role of Retinal Pigment Epithelium In Retinal Disorders

视网膜色素上皮在视网膜疾病中的作用

基本信息

批准号：
7734598
负责人：
CHANDRASEK N NAGINENI
金额：
$ 21.26万
依托单位：
NATIONAL EYE INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/7734598
关键词：
3&apos Untranslated Regions Adhesions Affect Age related macular degeneration Angiogenic Factor Anti-Inflammatory Agents Apoptosis Attention Binding Birth Cell Culture System Cell Nucleus Cells Cessation of life Chondroitin Sulfate C Chondroitin Sulfate Proteoglycan Choroid Collagen Cytoplasm Disease Enzymes Epithelial Etiology Extracellular Matrix Extracellular Matrix Proteins Eye Fibronectins Functional disorder Gene Expression Genes Genome Growth Growth Factor Human Human Genome Immunoassay In Vitro Inflammation Inflammatory Inorganic Sulfates Interferons Interleukin-1 Interleukin-11 Lead Mediator of activation protein Messenger RNA MicroRNAs Microarray Analysis Modeling Molecular Molecular Profiling Molecular and Cellular Biology Mus Nature Neurons Oligonucleotides Pathway interactions Photoreceptors Pigments Platelet-Derived Growth Factor Play Polymerase Chain Reaction Process Production Proliferative Vitreoretinopathy Property Proteoglycan Reaction Regulation Reporting Research Retina Retinal Retinal Detachment Retinal Diseases Retinal Neovascularization Role Signal Transduction Staining method Stains Structure of retinal pigment epithelium System Time Transforming Growth Factor beta Translations Tumor Necrosis Factor-alpha Tumor Necrosis Factors Unspecified or Sulfate Ion Sulfates Untranslated RNA Up-Regulation Vascular Endothelial Growth Factor A Vascular Endothelial Growth Factor C Vascular Endothelial Growth Factors Visual impairment Wild Type Mouse angiogenin base chemokine cytokine extracellular human TNF protein in vivo Model mRNA Transcript Degradation macromolecule macrophage mouse model nestin protein programs receptor tool

项目摘要

Retinal pigment epithelium (RPE), a single layer of cells present between the retina and choroid in the eye, is vital for the normal functioning of the retina. Many of the inflammatory, infectious and other diseases of the retina are associated with the degeneration and /or dysfunction of the RPE. We have developed a human RPE cell culture system and have used this as a model to investigate the various roles of RPE in the pathophysiology of retinal disorders. We focused our attention on transforming growth factor-beta (TGF-β), since TGF-β is involved in retinal disorders of proliferative, degenerative, inflammatory and infectious etiology. Age related macular degeneration (ARMD), proliferative vitreoretinopathy (PVR) and retinal detachments (RD) are the leading causes of visual impairment. We evaluated the effects of TGF-β on human RPE cells by microarray analyses by using GeneChip (Human Genome U133 plus array, Affymetrix). This system provides genome-wide changes in the expresssion of most of the characterized human genes. TGF-β significantly enhanced the expression of many of the extracellular matrix proteins (ECM) such as collagens, fibronectin, thrombospondin and chondritin sulfate proteoglycans as well as many growth factors such as vascular endothelial growth factors (VEGF) and platelet derived growth factors (PDGF). It is important to note that ECM and growth factors are associated with many of the blinding retinal disorders like ARMD, PVR, RD. We are using microarray analysis to identify the expression of extracellular macromolecules, not known to be present in the retina,and their possible role in retinal pathophysiology. In order to study the role of ECM components and their regulation by TGF-β, we generated a mouse model by conditionally deleting TGF-β signaling in the neurons (cKO) by crossing TGF-β receptor I (TGF-β RI) floxed mice with nestin-Cre mice. The retinal detachments, seen in almost all of the cKO mice at birth, are at the RPE / photoreceptor layer junction of the neurosensory retina (NSR). The immunoassays for chondroitin-6-sulfate showed a very weak reaction in cKO mice in contrast to intense positive staining in the photoreceptor layer in wild-type mice. Studies with our cKO model suggest that the lack of functional TGF-β RI in retinal cells leads to decreased levels of chondroitin sulfate proteoglycans in the subretinal space and photoreceptor layers. This, in turn, causes retinal detachment due to the loss of adhesion of the NSR to RPE. We have previously reported that TGF-β is a potent stimulator of VEGF and PDGF expression by human RPE cells. Since inflammation in retinal disorders (ARMD) is now recognized as a key component, we evaluated the role of inflammatory mediators on the expression of VEGF, a known agent in retinal neovascularization in ARMD. Our results showed that Interferon-γ (IFN-γ), interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α) enhance significantly the secretion of VEGF-A and VEGF-C by RPE and choroidal cells. IFN-γ, IL-1, TNF-α and other cytokines are produced in the retinal microenvironment by macrophages and other infilterating cells into the retina and choroid. We are evaluating the mechanisms of the regulation of VEGF-A, VEGF-C and other angiogenic factors(angiogenin and pigment epithelial derived growth factor) by inflammatory mediators to delineate the involvement of inflammatory processes in ARMD and other retinal neovascularization disorders. Affymetrix microarray studies for gene expression profiles also surprisingly revealed the induction of interleukin-11 (IL-11) by TGF-β. IL-11 acts as an anti-inflammatory agent by inhibiting the macrophage production of TNF-α and IL-1. IL-11 was also shown to have cytoprotective properties by inhibiting cellular death pathway known as apoptosis. We found that IFN-γ dowwn regulates IL-1 and TNF-α induced IL-11 secretion by RPE and choroidal cells. In contrast, TGF-β induced IL-11 secretion was not affected by IFN-γ. We are evaluating the mechanisms of the regulation of expression of IL-11 and potential usefulness of IL-11 as an agent in the protection of retina from oxidative and inflammatory insults. Recent discoveries in cellular and molecular biology point to the microRNAs(miRNAs)as potential regulators of gene expression. miRNAs are noncoding RNA oligonucleotides of 20-25 bases. So far only about 500 genes have been identified, and their products are processed both in nucleus and cytoplasm by a variety of enzymes to produce mature forms. miRNAs bind to 3'untranslated regions of messengerRNAs(mRNA)that may lead to mRNA degradation and/or inhibition of translation. Potential applications of miRNAs as tools in understanding and treatment of ocular diseases are being investigated. Using microRNA array analysis, we studied the regulation of miRNA expression in human RPE cells by inflammatory mediators. Initial results showed significant upregulation of mir-155 and mir-146 and these results have been validated by Real Time PCR analysis. We are currently investigating the role of mir-155 and mir-146 in the regulation of the expression of various cytokines, chemokines and growth factors associated with retinal disorders.

视网膜色素上皮（RPE）是存在于视网膜和脉络膜之间的单层细胞，对视网膜的正常功能至关重要。视网膜的许多炎症、感染性疾病和其他疾病都与视网膜的变性和/或功能障碍有关。我们已经开发了一个人类RPE细胞培养系统，并以此为模型来研究RPE在视网膜疾病病理生理中的各种作用。我们将注意力集中在转化生长因子- β (TGF-β)上，因为TGF-&#946参与了视网膜增生、退行性、炎症和感染性疾病的病因。年龄相关性黄斑变性（ARMD）、增殖性玻璃体视网膜病变（PVR）和视网膜脱离（RD）是导致视力损害的主要原因。我们使用GeneChip （human Genome U133 + array, Affymetrix）进行微阵列分析，评估TGF-&#946；对人RPE细胞的影响。该系统提供了大多数特征人类基因表达的全基因组变化。TGF-显著增强了多种细胞外基质蛋白（ECM）的表达，如胶原蛋白、纤维连接蛋白、血小板反应蛋白、硫酸线粒体蛋白多糖以及多种生长因子，如血管内皮生长因子（VEGF）、血小板衍生生长因子（PDGF）。值得注意的是，ECM和生长因子与许多致盲性视网膜疾病（如ARMD， PVR， RD）有关。我们正在使用微阵列分析来鉴定细胞外大分子的表达，这些分子在视网膜中不存在，以及它们在视网膜病理生理中的可能作用。