ROLE OF VIL-6 IN PRIMARY EFFUSION LYMPHOMAS

人类疱疹病毒-8 （HHV-8）是最近发现的一种病毒，其序列在所有类型的卡波西肉瘤（艾滋病相关、经典、地方性）、艾滋病相关原发性积液性淋巴瘤（PEL）和多中心Castleman病（MCD）病变中均有发现。最近的报道表明，HHV-8也可能与多发性骨髓瘤（MM）有关。已经提出HHV-8直接或间接参与这些疾病的发生和进展。相关的研究结果表明，细胞因子，特别是IL-6，与KS、PEL、MCD和MM的发展有关；IL-6促进KS、PEL和骨髓瘤细胞的生长，在MCD病变和患者血清中发现IL-6水平升高。在完成病毒基因组测序之前，部分序列分析确定HHV-8是γ -疱疹病毒亚家族的成员，并且在序列数据可用的疱疹病毒中，它与猴疱疹病毒（HVS）最密切相关。根据推测HHV-8和HVS基因组之间的一般遗传共线性，我们在HHV-8中发现了一个γ -疱疹病毒分化的基因组位点，该基因组位点编码白细胞介素-6 （vIL-6）的同源物和三个β趋化因子同源物（vMIP-1A, vMIP-1B， BCK），其中两个与巨噬细胞炎症蛋白-1密切相关。我们假设HHV-8可能影响与病毒相关的疾病病理，这是通过病毒-6对HHV-8感染或周围细胞的直接有丝分裂刺激，以及通过v-趋化因子的趋化特性募集到感染组织的淋巴细胞分泌的细胞因子。本课题的重点是研究il -6对PEL细胞生长和信号转导的影响及其作用机制。具体目的是：(1)确定外源添加il -6对PEL细胞生长和存活的影响以及IL-6R对这些活性的影响；(2)在PEL细胞中鉴定VEGF种类及vIL-6诱导的有丝分裂/抗凋亡功能；(3)识别PEL细胞响应vIL-6而激活的信号转导通路，Jak/STAT和/或MAPK，以及MAPK通路中间体，并确定IL-6R在通路选择中的作用；(4)利用野生型和特异性改变形式的gp130和IL-6R进行体外vil -6受体结合试验，以表征vIL-6-gp130/IL-6R关联的性质和需求。这些联合研究将提供数据，以确定il -6和vIL-6对PEL细胞生长的相对贡献，确定vel -6在PEL细胞中介导作用的细胞内途径，并确定il -6与gp130和IL-6R的功能性关联特征。生成的数据将为设计针对PEL和其他HHV-8相关疾病特异性阻断vIL-6有丝分裂功能的潜在治疗策略提供基础。

Human herpesvirus-8 (HHV-8) is a recently discovered virus, sequences of which have been found consistently in Kaposi's sarcoma of all types (AIDS-associated, classical, endemic), in AIDS-associated primary effusion lymphoma (PEL), and at high frequency in lesions of multicentric Castleman's disease (MCD). Recent reports indicate that HHV-8 may also be associated with multiple myeloma (MM). It has been proposed that HHV-8 is directly or indirectly involved in the development and progression of these diseases. Of relevance are findings that implicate cytokines, particularly IL-6, in the development of KS, PEL, MCD and MM; IL-6 promotes the growth of KS, PEL and myeloma cells and is found at elevated levels in MCD lesions and patient sera. Prior to complete sequencing of the viral genome, partial sequence analysis determined that HHV-8 is a member of the gamma- herpesvirus subfamily and that of the herpesviruses for which sequence data are available it is most closely related to herpesvirus saimiri (HVS). On the basis of presumed general genetic collinearity between the genomes of HHV-8 and HVS, we identified a gamma-herpesvirus-divergent genomic locus in HHV-8 that encodes a homologue of interleukin-6 (vIL-6) and three beta- chemokine homologues (vMIP-1A, vMIP-1B, BCK), two of which are closely related to macrophage inflammatory protein-1. We hypothesize that HHV-8 could effect disease pathology with which the virus has been associated by direct mitogenic stimulation of HHV-8 infected or surrounding cells by vIL-6 and by cytokines secreted by lymphocytes recruited into infected tissues through the chemotactic properties of the v-chemokines. The focus of this proposal is to determine the effects and mechanisms of action of vIL-6 on PEL cell growth and signal transduction. The specific aims are (1) to determine the effects of exogenously added vIL-6 on PEL cell growth and survival and the influence of IL-6R on these activities; (2) to identify VEGF species and mitogenic/anti-apoptotic functions induced by vIL-6 in PEL cells; (3) to identify the signal transduction pathways, Jak/STAT and/or MAPK, and MAPK pathway intermediates that are activated in PEL cells in response to vIL-6 and determine the role of IL-6R in pathway selection; (4) to undertake in vitro vIL-6-receptor binding assays using wild-type and specifically altered forms of gp130 and IL-6R to characterize the nature of and requirements for vIL-6-gp130/IL-6R associations. These combined studies will provide data that determine the relative contributions of hIL-6 and vIL-6 to PEL cell growth, identify intracellular pathways through which the effects of vIL-6 are mediated in PEL cells, and determine the characteristics of functional vIL-6 associations with gp130 and IL-6R. The generated data will provide the basis for the design of potentially therapeutic strategies to specifically block vIL-6 mitogenic functions with respect PEL and other HHV-8 associated diseases.