KSHV interactions with host inflammasome components

产品说明：KSHV在病原学上与HIV-1感染患者口腔和其他身体部位的慢性炎症相关的卡波西肉瘤（KS）和原发性渗出性B细胞淋巴瘤（PEL）相关。炎症反应是KSHV发病机制的关键因素之一。KS病变以炎性细胞和细胞因子为特征。来自PEL的KS病变内皮细胞和B细胞系携带处于潜伏状态的KSHV基因组的多个拷贝。我们的长期目标是阐明KSHV的相互作用与宿主的先天性反应在原发感染和潜伏期，细胞因子诱导的途径，并确定其在KSHV发病机制中的作用。我们的理由是，这种详细的知识是至关重要的设计治疗策略，以控制KSHV感染，炎症和相关的恶性肿瘤。 KSHV感染的细胞分泌多功能IL-1 β和IL-18细胞因子到上清液中。IL-1 β和IL-18合成为无活性的proIL-1 β和proIL-18，然后通过活化的caspase-1进行加工。然而，半胱天冬酶-1本身作为半胱天冬酶原-1合成并经历活化，导致自动蛋白水解裂解。半胱天冬酶原-1激活由称为“炎性体”的分子平台介导，该分子平台由识别危险触发物的传感器蛋白、适配器ASC分子和半胱天冬酶原-1的同型相互作用形成。我们的研究表明，炎性小体的病原体感应功能也延伸到细胞核。在KSHV重新感染人微血管真皮内皮细胞（HMVEC-d）期间，γ-干扰素诱导蛋白（IFI 16）与KSHV基因组共定位于感染的内皮细胞核中，并与ASC和半胱氨酸天冬氨酸蛋白酶原-1相互作用以形成炎性体复合物。IFI 16还与KSHV基因组共定位在潜伏感染的内皮细胞和PEL细胞的细胞核中，并且在KSHV潜伏感染的细胞中仅IFI 16依赖性炎性体被组成性激活。人KS和PEL病变显示IFI 16-ASC炎性小体活化的证据。在γ1-EBV潜伏期I、II和III细胞中也观察到IFI 16-炎性小体的组成型诱导。结合KSHV和EBV在IFI 16-炎性体存在下潜伏的能力以及IFI 16与潜伏感染细胞中的KSHV和EBV基因组的关联，我们假设“IFI 16参与细胞核中外源附加体DNA的先天感知，并且KSHV利用IFI 16进行其潜伏”。这一假设将通过三个创新和相互关联的具体目标进行检验。 这些研究是有意义的，因为这样的阐明将导致设计治疗策略以控制KSHV诱导的炎症和相关的恶性肿瘤。这些也将深刻地增强目前细胞核中先天感觉的概念，并将导致新的技术和治疗，不仅有利于KSHV研究领域，也有利于其他领域。

DESCRIPTION: KSHV is etiologically associated with chronic inflammation associated Kaposi's sarcoma (KS) and primary effusion B-cell lymphoma (PEL) in oral and other body sites that occur in HIV-1 infected patients. The inflammatory response is one of the key elements of KSHV pathogenesis. KS lesions are characterized by inflammatory cells and cytokines. The KS lesion endothelial cells and B-cell lines from PEL carry multiple copies of the KSHV genome in a latent state. Our long term goals are to elucidate KSHV's interactions with the host innate response during primary infection and latency, the pathways of cytokine induction and to define their role in KSHV pathogenesis. Our rationale is that such detailed knowledge is crucial for designing therapeutic strategies to control KSHV infection, inflammation and the associated malignancies. KSHV infected cells secrete multi-functional IL-1ß and IL-18 cytokines into the supernatants. IL-1ß and IL-18 are synthesized as inactive proIL-1ß and proIL-18 and then undergo processing by activated caspase-1. However, caspase-1 itself is synthesized as a procaspase-1 and undergoes activation leading into an auto- proteolytic cleavage. Procaspase-1 activation is mediated by a molecular platform called an "inflammasome" that is formed by homotypic interactions of a sensor protein recognizing the danger trigger, an adaptor ASC molecule, and procaspase-1. Our studies have demonstrated that the pathogen sensing functions of the inflammasome also extends into the nucleus. During de novo KSHV infection of human microvascular dermal endothelial (HMVEC-d) cells, gamma-interferon-inducible protein (IFI16) is colocalized with the KSHV genome in the infected endothelial cell nucleus, and interacted with ASC and procaspase-1 to form an inflammasome complex. IFI16 also colocalized with the KSHV genome in the nuclei of latently infected endothelial and PEL cells, and only the IFI16 dependent inflammasome is constitutively activated in KSHV latently infected cells. Human KS and PEL lesions showed evidence of IFI16-ASC inflammasome activation. Constitutive induction of the IFI16-inflammasome was also observed in γ1-EBV latency I, II and III cells. Together with the ability of KSHV and EBV latency in the presence of the IFI16-inflammasome and association of IFI16 with KSHV and EBV genome in the latently infected cells, we hypothesize that "IFI16 is involved in the innate sensing of foreign episomal DNA in the nucleus and KSHV utilizes IFI16 for its latency". This hypothesis will be tested by three innovative and interlinked specific aims. These studies are significant since such elucidation wil lead into designing therapeutic strategies to control KSHV induced inflammation and the associated malignancies. These will also profoundly enhance the current concepts of innate sensing in the nucleus and will lead into new technologies and treatments that will benefit not only the KSHV area of research but also other fields.