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

• 批准号: 7322191
• 负责人: CHANDRASEK N NAGINENI
• 金额: --
• 依托单位: NATIONAL EYE INSTITUTE
• 依托单位国家: 美国
• 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/7322191
• 关键词: Role; Retinal; Pigment; Epithelium; Disorders

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-b), since TGF-b is involved in retinal disorders of proliferative, inflammatory and infectious etiology. Retinal and Choroidal neovascularization (CNV), observed during age related macular degeneration (ARMD) and proliferative vitreoretinopathy (PVR) associated with retinal detachments, are the leading causes of visual impairment. Elevated expression of TGF-b in vitreous, retina and RPE has been closely correlated with the retinal fibrosis and CNV. However, the sources and production of TGF-b by retinal resident cells were not clearly known. We have examined the role of various cytokines and other mediators in the regulation of the expression of TGF-b by RPE. Our results demonstrated a differential role for interferon (IFN)-g, which enhanced TGF-b1 but inhibited TGF-b2 production. Interestingly, other inflammatory mediators such as tumor necrosis factor (TNF)-alpha and interleukin-1 enhanced the secretion of both TGF-b1 and TGF-b2. These observations were corroborated by mRNA analyses by Real-time and conventional RT-PCR methods. The contrasting effects of IFN-g on TGF-b1 and TGF-b2 sheds new light on the possible differential actions of TGF-b1 and TGF-b2 in the pathophysiology of retinal diseases. Further studies are in progress to evaluate the potential role of TGF-b1 and TGF-b2 and their receptors in the retinal diseases. We evaluated the effects of TGF-b on human RPE cells by microarray analyses by using GeneChip (Human Genome U133 plus array,Affymetrix). This will provide genome-wide changes in the expresssion of most of the characterized human genes. TGF-b significantly enhanced the expressionn of many of the extracellular matrix proteins(ECM)such as collagens, fibronectin, thrombospondin and chondritin sulfate proteoglycans. TGF-b treatment also enhanced the expression of vascular endothelial growth factors, connective tissue growth factor and platelet derived growth factors. ECM and growth factors are assocciated with many of the blinding retinal disorders like age related macular degeneration, retinal detachments and proliferative vitreoretinopathy. We are in the process of validation and quantitation of these results by Real Time PCR analyses. The role of ECM, growth factors and TGF-b in retinal diseases is the subject of our ongoing and future studies.

视网膜色素上皮（RPE）是存在于眼睛中的视网膜和脉络膜之间的单层细胞，对于视网膜的正常功能至关重要。视网膜的许多炎性、感染性和其它疾病与RPE的变性和/或功能障碍有关。我们已经开发了一种人RPE细胞培养系统，并以此为模型来研究RPE在视网膜疾病的病理生理学中的各种作用。我们将注意力集中在转化生长因子-β（TGF-β）上，因为TGF-β参与增殖性、炎症性和感染性病因的视网膜疾病。视网膜和脉络膜新生血管形成（CNV）是导致视力损害的主要原因，在年龄相关性黄斑变性（ARMD）和与视网膜脱离相关的增殖性玻璃体视网膜病变（PVR）中观察到。TGF-β在玻璃体、视网膜和RPE中的高表达与视网膜纤维化和CNV密切相关。然而，视网膜驻留细胞TGF-β的来源和产生尚不清楚。我们已经研究了各种细胞因子和其他介质在调节RPE表达TGF-β中的作用。我们的研究结果表明，干扰素（IFN）-g，增强TGF-β 1，但抑制TGF-β 2生产的差异作用。有趣的是，其他炎症介质，如肿瘤坏死因子（TNF）-α和白细胞介素-1增强TGF-β 1和TGF-β 2的分泌。通过实时和常规RT-PCR方法进行的mRNA分析证实了这些观察结果。IFN-g对TGF-β 1和TGF-β 2的对比效应揭示了TGF-β 1和TGF-β 2在视网膜疾病的病理生理学中可能的差异作用。TGF-β 1和TGF-β 2及其受体在视网膜疾病中的作用还有待进一步研究。 我们通过使用基因芯片（人类基因组U133加阵列，Affytron）的微阵列分析来评估TGF-β对人类RPE细胞的作用。这将在大多数特征化的人类基因的表达中提供全基因组变化。TGF-β显著增强许多细胞外基质蛋白（ECM）的表达，如胶原、纤连蛋白、血小板反应蛋白和硫酸纤维素蛋白多糖。TGF-β处理还增强了血管内皮生长因子、结缔组织生长因子和血小板衍生生长因子的表达。ECM和生长因子与许多致盲性视网膜疾病如年龄相关性黄斑变性、视网膜脱离和增殖性玻璃体视网膜病变相关。我们正在通过真实的时间PCR分析对这些结果进行验证和定量。ECM、生长因子和TGF-b在视网膜疾病中的作用是我们正在进行和未来研究的主题。