Regulation of Interferon Signaling by INI1/hSNF5 During HIV-1 Replication

描述（由申请人提供）：本提案的长期目标是描述HIV-1复制过程中宿主-病毒的动态相互作用，并利用这些信息开发新的有效策略来对抗艾滋病。INI 1/hSNF 5是HIV-1整合酶（integrase，IN）结合宿主因子，是哺乳动物染色质重塑SWI/SNF复合物的一个组分，参与转录调控。INI 1/hSNF 5与HIV-1 IN直接且强烈结合，并且INI 1/hSNF 5的片段跨越最小IN结合结构域，显性负抑制HIV-1复制。这些观察结果表明，INI 1/hSNF 5相互作用是HIV-1复制所必需的。最近的研究表明，INI 1/hSNF 5是一种肿瘤抑制因子，在横纹肌样肿瘤中发生双等位基因突变。我们试图研究全局基因表达谱，结果显示INI 1/hSNF 5在INI 1-/-横纹肌样细胞中高度刺激IFN信号诱导基因（ISG）和PML核体蛋白。这些结果为INI 1/hSNF 5在HIV-1复制中的作用提供了新的见解。我们假设INI 1是细胞抗病毒防御（先天免疫）的一个组成部分，是HIV-1复制过程中诱导IFN信号传导所必需的，HIV-1通过IN直接与INI 1/hSNF 5结合并在其复制过程中捕获它来破坏INI 1/hSNF 5的作用。为了检验这一假设，在特定的目标I中，我们将确定INI 1/hSNF 5是否是通过IFN、poly（I）：（C）和在HIV-1复制期间在T细胞中诱导IFN信号传导所必需的。我们将监测抗病毒基因（如IFIT 1、IFITM 1、OAS 2、MX2和PKR）、PML核体组分（如PML、Sp100、Sp110）和信号转导子（如STAT 1）的诱导。我们将把INI 1和ISG表达的下调效应与HIV-1复制联系起来。这些结果将确定INI 1/hSNF 5是否是HIV-1复制期间细胞抗病毒防御的组分。在具体目标II中，我们将确定HIV-1是否通过IN结合捕获INI 1而破坏INI 1诱导的抗病毒防御。我们将：（i）使用携带INI 1相互作用缺陷型IN突变体（H12 Y）和INI 1的转显性突变体（S6）的突变HIV-1病毒粒子;确定IN突变体H12 Y是否不能捕获INI 1并允许IFN信号传导;（ii）确定S6是否隔离IN并允许细胞INI 1启动IFN信号传导，并将S6的作用与S6的IN相互作用缺陷型突变体（E3）进行比较;（iii）为了确定在Gag-Pol的背景下IN是否能够隔离INI 1，我们将研究在HIV-1复制的晚期事件期间Gag-Pol的表达、ISG表达和内源性INI 1的再分布之间的时间关系。如果Gag-Pol表达能够在细胞质中隔离细胞INI 1，则这将导致HIV-1复制期间ISG表达的颠覆。这些结果将阐明HIV-1可能破坏INI 1诱导的细胞抗病毒防御的机制。我们希望，上述两个具体的目标将建立一个新的模式，在动态主机HIV-1的相互作用，并可能提供洞察力，开发新的抗病毒和疫苗的策略，以对付艾滋病。艾滋病仍然是一个主要的健康问题，因为目前的药物无法消除艾滋病毒-1由于耐药病毒的出现。因此，迫切需要确定新的靶点和开发新的治疗策略来对抗艾滋病。病毒与宿主在致病过程中存在着动态的相互作用。本申请的目的是测试一种新的假设，即与HIV-1蛋白（整合酶）之一结合的细胞蛋白INI 1/hSNF 5是细胞抗病毒防御的一个组成部分，并利用这种见解在未来开发新的抗艾滋病抗病毒策略。

DESCRIPTION (provided by applicant): The long-term goal of this proposal is to delineate the dynamic host-virus interactions during HIV-1 replication and use this information to develop novel and effective strategies to combat AIDS. INI1/hSNF5, is a HIV-1 integrase (IN) binding host factor, is a component of the mammalian chromatin-remodeling SWI/SNF complex involved in transcriptional regulation. INI1/hSNF5 directly and strongly binds to HIV-1 IN and a fragment of INI1/hSNF5, spanning the minimal IN-binding domain, dominant negatively inhibits HIV-1 replication. These observations suggested that INI1/hSNF5 interaction is required for HIV-1 replication. Recent studies demonstrate that INI1/hSNF5 is a tumor suppressor, biallelically mutated in rhabdoid tumors. Our attempt to study global gene expression profile revealed that INI1/hSNF5 stimulates a high degree of IFN signal induced genes (ISGs) and PML nuclear body proteins in INI1-/- rhabdoid cells. These results shed new insight on the role of INI1/hSNF5 in HIV-1 replication. We hypothesize that INI1 is a component of the cellular anti-viral defense (innate immunity) and is required for induction of IFN signaling during HIV-1 replication and that HIV-1 subverts the effect of INI1/hSNF5 by directly binding to it via IN and capturing it during its replication. To test this hypothesis, in the specific aim I we will determine if INI1/hSNF5 is required for inducing IFN signaling in T cells by IFNs, poly(I):(C) and during HIV-1 replication. We will monitor the induction of antiviral genes (e.g. IFIT1, IFITM1, OAS2, MX2 and PKR), PML nuclear body components (e.g. PML, Sp100, Sp110), and signal transducers (e.g. STAT1). We will correlate the effect of down-modulation of INI1 and ISG expression to HIV-1 replication. These results will establish if INI1/hSNF5 is a component of the cellular antiviral defense during HIV-1 replication. In the specific aim II we will determine if HIV-1 subverts the INI1-induced antiviral defense by capturing it via binding by IN. We will: (i) use a mutant HIV-1 virion harboring INI1-interaction-defective IN mutants (H12Y) and a transdominant mutant of INI1 (S6); determine if IN-mutants H12Y will be unable to capture INI1 and allow the IFN signaling; (ii) determine if S6 sequesters IN and allows cellular INI1 to mount IFN signaling and compare the effect S6 to an IN-interaction defective mutant of S6 (E3); (iii) To determine if IN within the context of Gag-Pol is able to sequester INI1, we will investigate the temporal relationship between expression of Gag-Pol, ISG expression and redistribution of endogenous INI1 during late events of HIV-1 replication. If Gag-Pol expression is able to sequester cellular INI1 in the cytoplasm, then this will lead to subversion of the ISG expression during HIV-1 replication. These results will shed light on the mechanism by which HIV-1 may subvert INI1-induced cellular antiviral defense. We hope that together the above two specific aims will establish a new paradigm in dynamic host-HIV-1 interaction and may provide insight for developing novel antiviral and vaccine strategies against AIDS. AIDS is still a major health problem because of the inability of current drugs to eliminate HIV-1 due to the emergence of the resistant viruses. Therefore, there is a dire need for identification of new targets and development of novel therapeutic strategies to combat AIDS. There is a dynamic interaction between host and the virus during pathogenesis. The aim of this application is to test a novel hypotheses that INI1/hSNF5, a cellular protein that binds to one of the HIV-1 proteins (integrase), is a component of the cellular antiviral defense and utilize this insight for developing novel antiviral strategies against AIDS in the future.