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是一种皮肤血管肿瘤，是艾滋病患者的主要肿瘤。现在清楚的是，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)中都能持续存在，因此人们普遍认为KSHV是KS的病原体。KS皮损中的感染细胞包括内皮细胞、梭形细胞和免疫浸润性细胞。KSHV感染人内皮细胞可导致这些细胞的长期增殖和存活。炎症细胞因子和先天免疫反应是KS病变的关键成分，有助于旁分泌介导的血管生成 感染细胞中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，先天性反应是在病毒进入过程中由包膜糖蛋白触发的，或者与病毒进入时一起触发的。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即时和长期后果。该项目的中心假设是KSHV被膜蛋白与微血管内皮细胞之间的相互作用触发信号转导通路，导致以细胞转录的大量重新编程为特征的先天和炎性免疫反应的激活。初步数据显示， 纯化的KSHV K8。1糖蛋白激活干扰素诱导的一个关键介质，并在细胞中诱导抗病毒状态。这一发现从根本上支持了总体假设。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、转录图谱和对诱导的关键先天免疫激活物的直接评估。其他实验旨在阐明KSHV包膜蛋白传递细胞外衍生信号的细胞机制。这个项目的最终目标是确定先天激活反应的启动机制。已知的KSHV细胞结合伙伴、硫酸乙酰肝素蛋白多糖和α3beta1整合素的相对贡献将被评估。此外，我们将直接测试KSHV受Toll样受体先天感知的假设，Toll样受体是传递激活反应的古老防御分子。这些研究目标的成功完成将为KSHV的发病机制/肿瘤发生提供新的见解，并对未来的疫苗设计产生影响。

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.