Kaposi's Sarcoma-associated Herpesvirus Mimics of Cellular microRNAs

摘要 卡波西氏肉瘤相关疱疹病毒(KSHV)引起艾滋病相关恶性肿瘤 肉瘤(KS)和原发性渗出性淋巴瘤(PEL)，由KSHV感染内皮细胞(ECs)引起 和B细胞。KSHV编码一组微RNA(MiRNAs)，其意义基本未知 KSHV相关疾病。我们已经证明了KSHV miR-K11、miR-K3和miR-K10a 分别抑制细胞miR-155、miR-23和miR-142-3p的mRNA靶点。这项提议的目标是 了解这种拟态在PEL和KS发病机制中的潜在意义。我们的预赛 数据表明miR-K3和miR-K11共同对PEL来源的细胞系和 协同作用于生存信号和B细胞增殖的靶向抑制因子。因此，在目标1中，我们建议 B细胞对miR-K3和miR-K11的表型和机械特性的要求 KSHV的转型。MiR-K10a的AIMS 2和3地址功能。MIR-K10a表达自 Kaposin：一种编码序列，具有已知的致癌特性。我们的初步实验表明 MIR-K10a是这一转化活动的实际介体。因此，在目标2中，我们建议进一步 鉴定miR-K10a的致癌特性，并阐明其潜在机制，基于 已经确定了具有转型角色的候选目标。我们对miR-K10a靶的分析和 初步实验表明，miR-K10a在内皮细胞中发挥作用，破坏黏附连接(AJs)和 重塑肌动蛋白细胞骨架。MIR-K10a的表达导致内皮细胞显著延长，这让人想起 感染KSHV的梭形细胞是KS的标志。因为AJS和链接的肌动蛋白 细胞骨架在血管完整性、血管生成和维持内皮细胞静止中发挥重要作用 通过拮抗生长因子信号转导途径，miR-K10a对生长因子信号转导途径的失控可能直接影响KS的发病机制。在……里面 目标3，因此，我们建议从表型和机制上表征miR-K10a如何影响这些 结构和相关的信号通路。综上所述，拟议的实验将确定 这些KSHV miRNAs在KSHV肿瘤发生中的作用。

Summary Kaposi's Sarcoma-associated herpesvirus (KSHV) causes the AIDS-associated malignancies Kaposi's Sarcoma (KS), and primary effusion lymphoma (PEL), resulting from KSHV-infection of endothelial cells (ECs) and B cells, respectively. KSHV encodes a set of microRNAs (miRNAs) with largely unknown significance to KSHV-associated disease. We have demonstrated that the KSHV miRNAs miR-K11, miR-K3 and miR-K10a repress mRNA targets of cellular miR-155, miR-23 and miR-142-3p, respectively. The goal of this proposal is to understand the potential significance of this mimicry to the pathogenesis of PEL and KS. Our preliminary data suggest that miR-K3 and miR-K11 together are essential for the survival of PEL-derived cell lines and synergize to target repressors of survival signaling and B-cell proliferation. In Aim 1, we therefore propose to phenotypically and mechanistically characterize the requirement for miR-K3 and miR-K11 for B-cell transformation by KSHV. Aims 2 and 3 address functions of miR-K10a. miR-K10a is expressed from the Kaposin A coding sequence, which has known oncogenic properties. Our preliminary experiments suggest that miR-K10a is the actual mediator of this transforming activity. In Aim 2, we therefore propose to further characterize the oncogenic properties of miR-K10a and to elucidate the underlying mechanism, based on already identified candidate targets with roles in transformation. Our analysis of miR-K10a targets and preliminary experiments suggest that miR-K10a functions in ECs to disrupt adherens junctions (AJs) and to remodel the actin cytoskeleton. miR-K10a expression caused a striking elongation of ECs, reminiscent of the KSHV-infected infected spindle cells that are the hallmark of KS. Because AJs and the linked actin cytoskeleton play important roles in vascular integrity, angiogenesis and the maintenance of EC quiescence by antagonizing growth factor signaling, their deregulation by miR-K10a may directly impact KS pathogenesis. In Aim 3, we therefore propose to phenotypically and mechanistically characterize how miR-K10a affects these structures and associated signaling pathways. Together, the proposed experiments will identify key roles of these KSHV miRNAs in KSHV oncogenesis.