Role of Cyclooxygenase-2 and PGE2 in KSHV pathogenesis

描述(由申请人提供)：卡波西肉瘤相关疱疹病毒(KSHV/HHV-8)与卡波西肉瘤(KS)、一种多灶性血管增生性疾病以及原发渗出性淋巴瘤(PEL)和多中心Castleman病(MCD)有关。在KS内皮细胞中，KSHV以潜伏期形式存在，表达潜伏期相关核抗原(LANA或ORF73)、ORF72(v-细胞周期蛋白)、K13(v-flip)和Kaposin(K12)基因。亚群(1%)的炎性细胞和梭形细胞显示裂解的KSHV复制。在体外，KSHV感染会导致潜伏感染，从而为研究病毒和宿主因素参与潜伏感染的建立和维持提供了一个很好的体外模型。原代人微血管内皮细胞(HMVEC-d)和成纤维细胞(HFF)体外感染的特点是诱导原有宿主信号级联反应，潜伏期相关的ORF73、ORF72和K13基因持续表达，KSHV潜伏基因在内皮细胞表达暂时消失。KSHV感染HMVEC-d和HFF细胞可诱导血管生成应激反应基因COX-2基因表达上调。我们的研究表明，这也与COX-2‘S稳定的炎性代谢产物PGE_2的释放有关。更令人兴奋的是，我们发现KSHV诱导的COX-2/PGE2在潜伏的ORF73基因表达的持续表达中起作用。从这些研究中，我们推测KSHV利用COX-2和其他宿主细胞基因在建立潜伏感染和免疫调节方面具有优势。为了检验这一假设，我们制定了两个主要的具体目标。在特定的目标1中，我们将确定KSHV感染细胞中COX-2转录和转录后调控的分子机制，以及它在KSHV感染、炎症、血管生成和肿瘤发生中的作用。在特定的目标2中，我们将破译COX-2/PGE2介导的靶点维持的机制，这些靶点可用于治疗KSHV相关肿瘤和防止KS病变的发展。公共卫生相关性卡波西肉瘤相关疱疹病毒与艾滋病毒感染患者中一种主要的血管肿瘤有关，称为卡波西肉瘤(KS)，一种称为体腔淋巴瘤的淋巴瘤，以及某些形式的严重淋巴结肿大，称为Castleman病。我们的研究旨在更好地了解KS发展背后的驱动力，这反过来将导致更好地治疗KSHV感染和预防KS病变。

DESCRIPTION (provided by applicant): Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) is etiologically associated with Kaposi's sarcoma (KS), a multi-focal angioproliferative disease and with primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). In KS endothelial cells, KSHV is detected in a latent form and expresses the latency-associated nuclear antigen (LANA or ORF73), ORF72 (v-cyclin), K13 (v-FLIP) and Kaposin (K12) genes. A sub-population (<1%) of inflammatory and spindle cells display lytic KSHV replication. In vitro KSHV infection leads to latent infection and thus provides a good in vitro model for studying viral and host factors involved in the establishment and maintenance of latency. In vitro infection of primary human microvascular endothelial cells (HMVEC-d) and fibroblast cells (HFF) is characterized by the induction of pre-existing host signal cascades, sustained expression of latency- associated ORF73, ORF72 and K13 genes, transient expance of KSHV latent gene expression in endothelial cells. KSHV infection of HMVEC-d and HFF cells induced a strong up-regulation of COX-2 gene, an angiogenic stress response gene. Our studies demonstrate that this is also associated with the release of COX-2's stable inflammatory metabolite PGE2. More excitingly, we show that KSHV-induced COX- 2/PGE2 plays roles in the continued expression of latent ORF73 gene expression. From these studies, we hypothesize that KSHV utilizes COX-2 and other host cell genes for its advantage in the establishment of latent infection and immune-modulation. To test this hypothesis, we have formulated two major specific aims. In Specific aim 1, we will define the molecular mechanisms underlying the transcriptional and post-transcriptional regulation of COX-2 in KSHV infected cells and its role in successful KSHV infection, inflammation, angiogenesis and tumorigenesis. In Specific aim 2, we will decipher the mechanism of COX-2/PGE2 mediated maintenance of argets that can be used as therapeutic agents in the treatment of KSHV associated neoplasia and the prevention of KS lesion development. PUBLIC HEALTH RELEVANCE Kaposi's sarcoma-associated herpesvirus is associated with a leading vascular tumor of HIV infected-patients called Kaposi's sarcoma (KS), a lymphoma called body cavity-based lymphoma and some forms of severe lymph node enlargement, called Castleman's disease. Our research is directed towards finding a better understanding of the driving forces behind the KS development which in turn would lead to better treatment of KSHV infection and for the prevention of KS lesion.