HIV/TB Interaction in the Lung

描述(申请人提供)：HIV/TB在肺部的相互作用集中于调节肺泡巨噬细胞(AM)中的HIV-1复制，肺泡巨噬细胞是结核病(TB)病毒复制的主要来源。本实验室的工作表明：1)抑制C/EBPβ的产生是干扰素(干扰素)的作用。它还受到其他天然免疫介质的诱导，如SP-a。一旦表达，抑制性C/EBPbeta抑制静息AM中HIV-1复制和大多数促炎细胞因子启动子2)当单核细胞分化为巨噬细胞时，它们获得了产生显性负C/EBPβ转录因子的能力。3)在结核病期间，淋巴细胞与AM之间的接触推动AM中HIV-1的高水平复制淋巴细胞/AM接触和细胞因子都是最大限度激活LTR所必需的。淋巴细胞/AM接触下调了主要的负C/EBPbeta，抑制了HIV-1 LTR；而细胞因子激活了NF-kappaB，刺激了HIV-1 LTR。4)在小鼠脓毒症过程中，CD40的表达是需要下调的。初步数据现在表明，PU.1和CREM在静息AM中表达，但在结核病期间不表达。PU.1和CREM在其他系统中都是转录抑制因子。此外，一部分艾滋病合并结核病的患者表现出以中性粒细胞(PMN)为主的炎症。PMN在体内和体外刺激HIV-1复制和突变。充分诱导HIV-1复制和LTR功能需要PMN的接触和可溶性因子。与淋巴细胞一样，PMN也表达CD40L和CD28。与淋巴细胞不同，PMN表达LFA-1，与巨噬细胞ICAM-1结合，PMN衍生的过氧化氢是一种激活核因子-kappaB的可溶性因子。PMN接触下调抑制性C/EBPβ、CREM和PU。AM中的1个肺结核患者血清可溶性ICAM-1水平升高，CD40L被募集到PMN脂筏上。CD40L、CD28和CD11a抗体可抑制PMN脂筏的活性。PMN脂筏和抗CD40、B7和ICAM-1的交联型抗体聚集巨噬细胞CD40、B7和ICAM-1，并取消抑制C/EBPβ的表达。这些数据导致假设抑制性C/EBPbeta是抑制静息AM中HIV LTR活性的多个抑制子之一此外，PMN是先天免疫反应中的一种细胞成分，可以通过细胞接触来解除对LTR的抑制，并通过可溶性因子激活LTR。这两个步骤的过程有助于在机会性感染期间AM中高水平的HIV-1复制。这项提案将调查PU的作用。1和CREM是AM中HIV-1复制的抑制物，以及PMN在促进肺中HIV-1复制中的作用。

DESCRIPTION (provided by applicant): HIV/TB interaction in the lung has focused on regulation of HIV-1 replication in alveolar macrophages (AM), the major source of viral replication in tuberculosis (TB). Work performed in this laboratory has demonstrated: 1) Production of inhibitory C/EBPbeta is an interferon (IFN) effect. It is also induced by other innate immune mediators such as SP-a. Once expressed, inhibitory C/EBPbeta suppresses HIV-1 replication and most proinflammatory cytokine promoters in resting AM. 2) As monocytes differentiate to macrophages, they gain the ability to produce a dominant negative C/EBPbeta transcription factor. 3) During TB, contact between lymphocytes and AM drives high-level HIV-1 replication in AM. Both lymphocyte/AM contact and cytokines are required for maximal LTR activation. Lymphocyte/AM contact down-regulates the dominant negative C/EBPbeta, de-repressing the HIV-1 LTR; while cytokines activate NF-kappaB, stimulating the HIV-1 LTR. 4) In mice, CD40 expression is required for de-repression during sepsis. Preliminary data now demonstrate that PU.1 and CREM are expressed in resting AM but not during TB. Both PU.1 and CREM are transcriptional repressors in other systems. In addition, a subset of AIDS patients with TB demonstrates neutrophil (PMN) predominant inflammation. PMN stimulate HIV-1 replication and mutation in vivo and in vitro. Full induction of HIV-1 replication and LTR function requires PMN contact and soluble factors. Like lymphocytes, PMN express CD40L and CD28. Unlike lymphocytes, PMN express LFA- 1, which binds macrophage ICAM-1, and PMN-derived peroxide is a soluble factor that activates NF-kappaB. PMN contact down-regulates inhibitory C/EBPbeta, CREM and PU. 1 in AM. TB patients have elevated levels of soluble ICAM-1, which recruits CD40L to PMN lipid rafts. Antibodies to CD40L, CD28 and CD11a inhibit the activity of PMN lipid rafts. PMN lipid rafts and cross-linking antibodies to CD40, B7 and ICAM-1 aggregate macrophage CD40, B7 and ICAM-1 and abolish inhibitory C/EBPbeta expression. These data led to the hypothesis that inhibitory C/EBPbeta is one of multiple repressors inhibiting HIV LTR activity in resting AM. Further, PMN are a cellular component of the innate immune response that can de-repress the LTR by cellular contact and activate the LTR by soluble factors. This two-step process contributes to high-level HIV-1 replication in AM during opportunistic infection. This proposal will investigate the role of PU. 1 and CREM as inhibitors of HIV-1 replication in AM and the role of PMN in enhancing HIV-1 replication in the lung.