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本作用。其结构和功能作用的改变可导致光感受器和视力的丧失。我们已经广泛地研究了RPE细胞作为眼后极内的重要免疫调节细胞。我们对RPE细胞的研究活动可以分为三类：正常细胞功能研究，细胞因子相互作用和感染过程。该项目集中于研究细胞因子与免疫系统细胞和眼部微环境细胞相互作用的方式。这些研究表明，甜菜碱介导的RPE细胞活化可能是眼免疫的基本组成部分，也是RPE细胞移植的重要方面。在过去的一年中，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学标志物。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（RPE）细胞中的表达和功能。真实的时间PCR分析揭示了TLR 1至7、9和10在RPE细胞中的基因表达。TLR 1和TLR 3是最高表达的TLRs。TLR 3是病毒复制的中间体dsRNA的受体。由于RPE细胞表达TLR 3，并且经常是视网膜内病毒复制的位点，我们评估了TLR 3信号传导，发现IFN-β是产生的关键分子之一。RPE细胞上TLR的存在和RPE细胞中产生的TLR信号传导表明这些分子可能在视网膜内的先天性和适应性免疫应答中起重要作用。 由于IFN-β是由RPE细胞产生的，我们已经开始研究以评估IFN-β对RPE细胞的各种功能的影响。 微阵列分析显示，在IFN-β处理的细胞中，22，283个基因中有480个基因上调或下调超过2倍，39个基因变化超过4倍。 视网膜血管炎是眼部炎症的主要组成部分，在特发性葡萄膜炎和白塞病患者的视网膜组织损伤中起作用。 我们发现视网膜血管炎患者血清中选定的可溶性粘附分子和细胞因子水平发生了改变。 1型IFN、IFN-α和IFN-β在正常个体中检测不到，但在白塞病患者血清中高达39%和葡萄膜炎患者血清中高达47%检测到。 我们的体外研究结果进一步证实了视网膜血管内皮细胞可以被TLR 3激活产生sE-selectin、sICAM-1和IFN-β。 对先天免疫信号的进一步分析可能为今后研究视网膜血管炎的致病机制和治疗方法提供新的靶点。

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.