HIV-induced redox stress and the alveolar macrophage as a resistant reservoir

描述(由申请人提供)：项目摘要/摘要这项题为“肺泡巨噬细胞池是艾滋病毒的储存库”的新提案解决了一个基本问题；具体地说，即使通过抗逆转录病毒疗法(ART)实现了外周病毒抑制，肺泡巨噬细胞池是否仍可作为艾滋病毒的储存库，如果是，该储存库如何改变肺泡腔内的环境并损害肺泡巨噬细胞的免疫功能？这是一个需要解决的关键问题，因为肺部感染仍然是艾滋病毒携带者死亡的主要原因，即使他们遵守抗逆转录病毒治疗。我们有令人信服的实验证据表明，艾滋病毒感染抑制了肺泡腔内的抗氧化防御，并导致严重的氧化还原压力。根据这一建议中提出的初步数据，我们假设HIV抑制Nrf2的表达和作用，Nrf2是激活抗氧化反应元件(ARE)的主要转录因子，部分是通过在这个脆弱的微环境中诱导锌缺乏，从而防止肺泡上皮和肺泡巨噬细胞产生谷胱甘肽和其他抗氧化剂，这些是维持肺泡空间内健康的氧化还原电位所必需的。我们进一步假设，由于对Nrf2-ARE信号通路的靶向抑制， HIV促进了自身感染肺泡巨噬细胞的能力，并积累了大量的细胞内前病毒池，从而在肺泡腔内产生了大量的HIV存储库。同时， HIV诱导的氧化应激将肺泡巨噬细胞转变为交替激活(即所谓的M2表型)。其结果是，肺泡巨噬细胞的天然免疫能力受损，这不仅使清除病毒库产生进一步的抵抗力，而且使感染者容易受到严重的肺部感染。我们由基础和临床研究人员组成的协作性团队将利用我们正在进行的针对HIV感染者的协作性临床研究。因此，我们不仅能够持续获得来自明确的HIV感染者亚群的肺泡上皮衬里液体和巨噬细胞，而且我们还拥有在HIV发病机制、代谢组学和氧化还原信号方面应用最先进的基本技术来测试我们的假设的专业知识。与此同时，我们已经在对抗逆转录病毒治疗免疫应答不足的HIV感染者进行膳食锌和S-腺苷蛋氨酸(一种硫醇抗氧化剂，其众多作用之一是增加肺泡内谷胱甘肽池)的前瞻性临床试验。这一独特的队列将为一项大规模扩大的临床试验奠定基础，这将使我们能够测试推论假设，即旨在提高锌的生物利用度和肺泡间隙内的氧化还原电位的治疗策略可以增强肺泡巨噬细胞的先天免疫功能，并显著减少肺部的艾滋病毒储存库。该项目将对我们如何针对肺泡巨噬细胞池以减少艾滋病毒负担以及改善这些脆弱个体的肺健康产生新的见解。

DESCRIPTION (provided by applicant): PROJECT SUMMARY/ABSTRACT This new proposal entitled "The alveolar macrophage pool is a reservoir of HIV" addresses a fundamental question; specifically, does the alveolar macrophage pool serve as a reservoir of HIV even when peripheral viral suppression is achieved by anti-retroviral therapy (ART) and if so, how does this reservoir alter the environment within the alveolar space and impair alveolar macrophage immune function? This is a critical question to address as lung infections remain the leading cause of death in persons living with HIV even when they are adherent to ART. We have compelling experimental evidence that HIV infection inhibits anti-oxidant defenses within the alveolar space and causes severe redox stress. Based on preliminary data presented in this proposal, we hypothesize that HIV inhibits the expression and actions of Nrf2, the master transcription factor that activates the anti-oxidant response element (ARE), in part by inducing zinc deficiency in this vulnerable microenvironment, and thereby prevents the alveolar epithelium and the alveolar macrophage from generating glutathione and other anti-oxidants that are critically required to maintain a healthy redox potential within the alveolar space. We further hypothesize that as a result of this targeted inhibition of the Nrf2-ARE signaling pathway, HIV promotes its own ability to infect alveolar macrophages and accumulate a large pool of intracellular pro-virus that produces a large HIV reservoir within the alveolar space. In parallel, HIV-induced oxidative stress shifts the alveolar macrophage toward alternative activation (so called 'M2 phenotype'). As a consequence, the innate immune capacity of the alveolar macrophage is impaired and this not only confers further resistance to clearing the viral reservoir but also renders the infected individual susceptible to serious lung infections. Our collaborative team of basic and clinical investigators will leverage our ongoing collaborative clinical studies in HIV-infected individuals. As a result, we not only have ongoing access to alveolar epithelial lining fluid and macrophages from well-defined subsets of HIV-infected individuals, we also have the expertise to apply state-of-the-art basic techniques in HIV pathogenesis, metabolomics, and redox signaling to test our hypotheses. In parallel, we are already conducting a prospective clinical trial of dietary zinc and S-adenosylmethionine (a thiol anti-oxidant that among its many actions increases the glutathione pool in the alveolar space) in HIV-infected individuals with inadequate immunological responses to ART. This unique cohort will form the foundation for a greatly expanded clinical trial that will enable us to test the corollary hypothesis that therapeutic strategies designed to improve zinc bioavailability and the redox potential within the alveolar space can enhance alveolar macrophage innate immune function and significantly decrease the HIV reservoir in the lung. This project will produce novel insights into how we can target the alveolar macrophage pool to decrease HIV burden as well as improve lung health in these vulnerable individuals.