Lung TACE, TNFalpha & TNFR Regulation of HIV Replication

描述（由申请人提供）：TNF α可能在HIV感染期间起致病作用，特别是在局部组织部位，如肺。新描述的TNF α转化酶（TACE）可能在调节TNF α活性中发挥核心作用，而TNF α活性反过来可能是HIV复制的主要决定因素。然而，TACE活性在肺中可能与外周血细胞或淋巴结组织显著不同。我们的初步数据显示，肺中的TNF活性，如通过TNF α激动剂和sTNFRII拮抗剂浓度确定的，随着HIV疾病的进展、CD 4细胞计数下降和病毒载量增加而降低。这与使用血浆或外周血单核细胞（PBMC）或仅测量血液中TNF α的激动剂而非拮抗剂活性的报道相反。我们的中心假设是，ERK信号传导减少和TACE活性增加导致HIV+受试者肺细胞中TNF活性的这些变化以及进行性HIV感染。我们有初步的数据来支持这一中心假设。我们将测试这些变化是否是由TACE对ERK的影响引起的，通过诱导型一氧化氮合酶（iNOS）和PC-PLC途径增加TACE，通过TNF α的自分泌效应，或通过Tp 12对TNF α翻译的转录后效应，以及它们是否仅限于肺中的特定细胞。在这些实验中，将使用在肺泡巨噬细胞（AM）慢性HIV感染的离体模型中检查的、在高效抗逆转录病毒治疗（HAART）前和后研究的精心选择的受试者的患者来源样本。将与同时获得的PBMC以及来自HIV阴性对照供体的AM和PBMC进行比较。ERK和TACE活性的变化将在真正的单细胞水平上与HIV复制和TNFa相关，使用肺细胞和组织中的定量图像分析来确定这些机制是否在AM或其他肺细胞中体内起作用。这个假设驱动的项目将提示抗TNF或抗TACE治疗是否会改善接受HAART的HIV感染者的免疫功能和病毒学控制。

DESCRIPTION (provided by applicant): TNFa may play a pathogenic role during HIV infection, especially at local tissue sites such as the lung. The newly described TNFa-converting enzyme (TACE) may play a central role in modulating TNFa activity, which in turn may be a major determinant of HIV replication. TACE activity may, however, differ markedly in lung as opposed to peripheral blood cells or lymph node tissues. Our preliminary data show that TNF activity in the lung, as determined by TNFa agonist and sTNFRII antagonist concentrations, decreases as HIV disease progresses, CD4 cell counts fall, and viral load increases. This stands in contrast to reports using plasma or peripheral blood mononuclear cells (PBMC), or that measure only agonist, but not antagonist, activity of TNFa in blood. Our central hypothesis is that decreased ERK signaling and increased TACE activity causes these changes in TNF activity with progressive HIV infection in lung cells of HIV+ subjects. We have preliminary data to support this central hypothesis. We will test whether these changes are caused by TACE effects on ERK, increased TACE through inducible nitric oxide synthase (iNOS) and PC-PLC pathways, through autocrine effects of TNFa, or by post-transcriptional effects of Tp12 on TNFa translation, and whether they are limited to particular cells in the lung. Patient-derived samples from carefully selected subjects studied pre- and post-highly-active antiretroviral therapy (HAART), examined in an ex vivo model of chronic HIV infection of alveolar macrophages (AMs), will be used in these experiments. Comparisons will be made with simultaneously obtained PBMC, and with AMs and PBMC from HIV-negative control donors. Changes in ERK and TACE activity will be correlated with HIV replication and TNFa on a true single cell level using quantitative image analysis in lung cells and tissues to determine whether these mechanisms are operative in vivo in A M s or other lungs cells. This hypothesis-driven project will suggest whether anti-TNF or anti-TACE therapies will improve immunologic function and virologic control in HIV-infected persons receiving HAART.