Project 4

卡波西肉瘤（KS）相关疱疹病毒（KSHV）或人类疱疹病毒8（HHV-8）最初是从KS病变中分离出来的。KS是一种皮肤血管性肿瘤，是艾滋病患者的主要肿瘤。现在很清楚，KSHV在所有形式的KS（经典的，地方性的，移植后的，和艾滋病相关的）中一致发现，导致广泛认为KSHV是KS的病原体。KS病变中的感染细胞包括内皮细胞、梭形细胞和免疫浸润细胞。KSHV感染人内皮细胞导致这些细胞的长期增殖和存活。炎性细胞因子和先天性免疫反应是KS病变的重要组成部分，促进旁分泌介导的血管生成 以及感染细胞的裂解状态与潜伏状态。KSHV激活炎症和先天免疫反应的机制尚不清楚。我们实验室最近的发现表明，先天性反应是由包膜糖蛋白在病毒进入期间或与病毒进入一致时触发的。该项目的目标是确定KSHV包膜蛋白和内皮细胞分子之间的初始相互作用，并表征这些相互作用的直接和长期后果。该项目的中心假设是KSHV包膜蛋白与微血管内皮之间的相互作用触发信号转导途径，导致以细胞转录的实质性重编程为特征的先天性和炎症性免疫应答的激活。初步数据显示， 纯化的KSHV K8。1糖蛋白激活干扰素诱导的关键介质并诱导细胞中的抗病毒状态。这一发现从根本上支持了整个假设。为了表征KSHV引起的细胞基因表达的变化：将测量细胞相互作用、转录谱分析和诱导的关键先天免疫激活因子的直接评估。其他实验的目的是阐明参与KSHV包膜蛋白的细胞外衍生信号的传输的细胞机制。本项目的最终目标是确定先天激活反应的启动机制。将评价已知KSHV细胞结合伴侣、硫酸乙酰肝素蛋白聚糖和α 3 β 1整联蛋白的相对贡献。此外，我们将直接测试的假设，KSHV是受先天感觉Toll样受体，古老的防御分子，传输激活反应。这些研究目标的成功完成将产生新的见解KSHV的发病机制/肿瘤发生，以及对未来的疫苗设计的影响。

Kaposi's sarcoma (KS)-associated herpesvirus (KSHV), or human herpesvirus 8 (HHV-8), was originally isolated from a KS lesion. KS is a vascular tumor of the skin that is the leading neoplasm of AIDS patients. It is now clear that KSHV is consistently found in all forms of KS (classical, endemic, post transplant, and AIDS-related), resulting in the widely held view that KSHV is the etiologic agent of KS. Infected cells in KS lesions include endothelial cells, spindle cells and immune infiltrating cells. KSHV infection of human endothelial cells causes long-term proliferation and survival of these cells. Inflammatory cytokines and innate immune responses are critical components of KS lesions facilitating paracrine-mediated promotion of angiogenesis and lytic versus latency states in infected cells. The mechanism by which KSHV activates inflammatory and innate immune responses is unknown. Recent discoveries from our laboratory have revealed that innate responses are triggered by envelope glycoproteins during, or in concert with, virus entry. The goal of this project is to define the initial interactions between KSHV envelope proteins and endothelial cell molecules and to characterize the immediate and long-term consequences of these interactions. The central hypothesis of this project is that interactions between KSHV envelope proteins with the microvascular endothelium trigger signal transduction pathways that lead to activation of innate and inflammatory immune responses characterized by substantial reprogramming of cellular transcription. Preliminary data show that purified KSHV K8. 1 glycoprotein activates a key mediator of interferon induction and induces an antiviral state in cells. This finding lends fundamental support to the overall hypothesis. To characterize alterations in cellular gene expression as a consequence of KSHV:cell interactions, transcriptional profiling and direct assessment of induced key innate immune activators will be measured. Other experiments are designed to elucidate the cellular machinery involved in transmission of extracellular-derived signals by KSHV envelope proteins. The final objective of this project is to identify the initiating mechanism of the iinnate activation responses. The relative contribution of known KSHV cell binding partners, heparan sulfate proteoglycans and alpha3beta1 integrins will be evaluated. In addition, we will directly test the hypothesis that KSHV is subject to innate sensing by Toll-like receptors, ancient defense molecules that transmit activation responses. Successful completion of these research goals will yield new insights into KSHV pathogenesis/tumorigenesis as well as have implications for future vaccine design.