Heme oxygenase-1 and the bioenergetic threshold of latent TB and HIV co-infection

 描述（由申请人提供）： 全世界约有17亿人无症状地感染结核分枝杆菌（Mtb）。与艾滋病毒合并感染大大增加了发展为活动性结核病的风险，并构成全球公共卫生的主要障碍。值得注意的是，几乎没有基础研究来确定HIV调节Mtb进入、持续存在和从人类结核性肺中的持续状态出现以引起活动性TB疾病的机制。我们和其他人最近发现，一氧化碳（CO），由血红素加氧酶-1（HO-1），是结核分枝杆菌休眠信号，HO-1是必要的肉芽肿形成。此外，已显示HO-1抑制HIV复制。这些发现表明HO-1在控制TB/AIDS综合征中的关键作用，其中HO-1是潜伏期和储库维持的关键调节剂。我们的长期目标是了解HIV调节TB潜伏期的机制，以及如何操纵这些机制以达到治疗和预防目的。这项工作的目的是产生一个详细的，机械的理解HO-1和宿主生物能量学在结核病和艾滋病毒感染的背景下的作用。基于大量的初步数据，我们的中心假设是，HIV导致宿主细胞的生物能阈值失衡，这是由HO-1维持的，将平衡从潜伏性TB转移到活动性感染。我们的理由是，成功完成这项提案将有助于我们的知识基础的HO-1依赖性疾病功能的缺失，机械元素，没有它的TB潜伏期和HIV介导的再激活的机制不能完全理解。我们将应用新的技术，如实时代谢流量分析，以非侵入性地测量耗氧率（OCR），细胞外酸化率（ECAR），备用呼吸量（SRC），最大呼吸和ATP周转感染结核杆菌和/或艾滋病毒的细胞。这种强大的技术尚未应用于研究细菌/病毒宿主相互作用的生物能量学。我们还将利用新的HO-1转基因动物和人TB肺组织来准确描述HO-1在体内TB/HIV中的作用。此外，我们还将研究南非健康、潜伏性结核病、活动性结核病、结核病/艾滋病毒和艾滋病毒感染者的生物能量状态。在我们看来，这项研究是创新的，因为它代表了一种新的和实质性的脱离现状的方法，即应用新技术和独特的患者队列来研究HO-1和生物能量学作为范例，以更好地了解结核病/艾滋病。这一贡献是重要的，因为它是TB/HIV研究连续体的第一步，其将（i）从基础和临床研究的角度提供对HO-1在调节HIV和Mtb疾病中的作用的深入机制见解，（ii）表征TB/HIV患者的“生物能量阈值”，和（iii）鉴定人肺肉芽肿中Mtb/HIV共感染的细胞群体和细胞事件。总体而言，这些研究将为了解结核病和艾滋病毒在人类结核性肺中的持续存在提供新的基础。

 DESCRIPTION (provided by applicant): Approximately 1.7 billion people worldwide are asymptomatically infected with Mycobacterium tuberculosis (Mtb). Co-infection with HIV dramatically increases the risk of developing active TB and constitutes a major impediment to global public health. Notably, there has been little basic research toward defining the mechanisms by which HIV modulates Mtb to enter, persist and emerge from a persistent state in the human tuberculous lung to cause active TB disease. We and others have recently discovered that carbon monoxide (CO), generated by heme oxygenase-1 (HO-1), is an Mtb dormancy signal and that HO-1 is necessary for granuloma formation. Further, it has been shown that HO-1 inhibits HIV replication. These findings suggest a key role for HO-1 in control of the TB/AIDS syndemic wherein HO-1 is key regulator of latency and reservoir maintenance. Our long-term goal is to understand the mechanisms by which HIV modulates TB latency and how these mechanisms can be manipulated for therapeutic and prophylactic purposes. The objective of this work is to generate a detailed, mechanistic understanding of the role of HO-1 and host bioenergetics in the context of TB and HIV infection. Our central hypothesis, based on substantial preliminary data, is that HIV causes an imbalance in the bioenergetic threshold of host cells, which is maintained by HO-1, to shift the balance from latent TB to an active infection. Our rationale is that the successful completion of this proposal will contribute missing, mechanistic elements of HO-1-dependent disease function to our base of knowledge, without which the mechanism of TB latency and HIV-mediated reactivation cannot be fully understood. We will apply novel techniques such as real-time metabolic flux analysis to non-invasively measure the oxygen consumption rate (OCR), extracellular acidification rate (ECAR), spare respiratory capacity (SRC), maximal respiration and ATP turnover of cells infected with Mtb and/or HIV. This powerful technology has not yet been applied to study the bioenergetics of bacterial/viral host interaction. We also will exploit novel HO-1 transgenic animals, and human TB lung tissue to accurately describe roles for HO-1 in TB/HIV in vivo. Further, we will examine the bioenergetic status of healthy, latent TB, active TB, TB/HIV and HIV-infected patients in South Africa. The research is innovative, in our opinion, because it represents a new and substantive departure from the status quo by applying novel technologies and unique patient cohorts to examine HO-1 and bioenergetics as paradigms to better understand TB/HIV disease. This contribution is significant because it is the first step in the continuum of TB/HIV research that will (i) provide in-depth mechanistic insight from a basic and clinical research point of view into the role of HO-1 in regulating HIV and Mtb disease, (ii) characterize the "bioenergetic threshold" of TB/HIV patients, and (iii) identify the Mtb/HIV co-infected cell populations and cellular events in human lung granulomas. Overall, these studies will provide a new basis for understanding TB and HIV persistence in the human tuberculous lung.