Studies Of The Bioregulatory Aspects Of The Retinal Pigment Epithelial Cell

RPE细胞在维持神经视网膜的结构和生理完整性方面起着基础作用。其结构和功能的改变可导致光感受器和视力的丧失。RPE细胞作为眼后极内一种重要的免疫调节细胞，我们进行了广泛的研究。我们对RPE细胞的研究可分为三大类：正常细胞功能研究、细胞因子相互作用研究和感染过程研究。本项目主要研究细胞因子与免疫系统细胞和眼微环境细胞相互作用的途径。这些研究表明，细胞因子介导的RPE细胞活化可能是眼免疫的一个基本组成部分，也是RPE细胞移植的一个重要方面。在过去的一年里，我们研究了RPE细胞中的toll样受体（TLR）和与视网膜血管炎患者相关的可能的生物标志物。tlr是先天免疫的重要组成部分，参与宿主对微生物病原体的防御。我们评估了TLRs在人视网膜色素上皮细胞（RPE）中的表达和功能。Real - time PCR分析显示，tlr1 ~ 7,9和10基因在RPE细胞中表达。tlr1和3是表达量最高的TLR。tlr3是dsRNA的受体，dsRNA是病毒复制的中间体。由于RPE细胞表达tlr3，并且经常是视网膜内病毒复制的位点，我们评估了tlr3信号传导，发现ifn - β是产生的关键分子之一。RPE细胞上TLR的存在以及RPE细胞中由此产生的TLR信号表明，这些分子可能在视网膜内的先天和适应性免疫反应中发挥重要作用。由于ifn - β是由RPE细胞产生的，我们已经开始研究IFN-b对RPE细胞各种功能的影响。微阵列分析显示，在ifn - β处理的细胞中，22283个基因中有480个基因的上调或下调幅度大于2倍，39个基因的上调或下调幅度大于4倍。

The RPE cell plays a basic role in maintaining the structural and physiological integrity of the neural retina. Alterations in its structural and functional actions can result in loss of photoreceptors and vision. We have studied the RPE cell extensively as an important immunoregulatory cell within the posterior pole of the eye. Our research activities on RPE cells can be subdivided into three categories: normal cell function studies, cytokine interactions and infectious processes. This project has concentrated on studying the ways in which cytokines interact with cells of the immune system and with cells in the ocular microenvironment. These studies indicate that cytokine-mediated activation of RPE cells may be a basic component of ocular immunity and an important aspect of RPE cell transplantation. During the past year, we have studied the Toll-Like receptors (TLR) in RPE cells and possible biological markers associated with patients with retinal vasculitis. TLRs are crucial components of innate immunity that participate in host defense against microbial pathogens. We evaluated the expression and function of TLRs in human retinal pigment epithelial (RPE) cells. Real time PCR analysis revealed gene expression for TLR 1 to 7, 9 and 10 in RPE cells. TLR 1 and 3 were the most highly expressed TLRs. TLR 3 is the receptor for dsRNA, an intermediate of virus replication. Since RPE cells express TLR 3 and are frequently the site of virus replication within the retina, we evaluated TLR 3 signaling and found that IFN-beta is one of the key molecules produced. The presence of TLRs on RPE cells and the resultant TLR signaling in RPE cells suggest that these molecules may play an important role in innate and adaptive immune responses within the retina. Since IFN-beta is produced by the RPE cell we have initiated studies to evaluate the effects of IFN-b on the various functions of the RPE cell. Microarray analysis revealed that in IFN-beta treated cells, 480 genes out of 22,283 genes were up or down regulated by greater than 2 fold and 39 genes with greater than 4 fold changes. Retinal vasculitis is a major component of ocular inflammation that plays a role in retinal tissue damage in patients with idiopathic uveitis and Behcets disease. We found that levels of selected soluble adhesion molecules and cytokines were altered in the serum of patients with retinal vasculitis. Type 1 IFN, IFN-alpha and IFN-beta were not detectable in normal individuals but were detected in up to 39% of the serum from Behcets patients and 47% of uveitis patients. Our in vitro findings further demonstrated that the retinal vascular endothelial cell could be activated throuth TLR3 to produce sE-selectin, sICAM-1 and IFN-beta. Further analysis of innate immune signaling may prove to be a novel target for future studies on pathogenic mechanisms and therapeutic approaches in retinal vasculitis.