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)。与艾滋病毒的混合感染极大地增加了患活动性结核病的风险，并构成了全球公共卫生的主要障碍。值得注意的是，对于确定艾滋病毒调节结核分枝杆菌进入、持续和脱离人类结核病持续状态从而导致活动性结核病的机制，几乎没有基础研究。我们和其他人最近发现，由血红素加氧酶-1(HO-1)产生的一氧化碳(CO)是Mtb休眠信号，HO-1是肉芽肿形成所必需的。此外，已有研究表明，HO-1抑制艾滋病毒复制。这些发现表明，HO-1在控制结核病/艾滋病综合征中发挥了关键作用，其中HO-1是潜伏期和水库维护的关键调节因素。我们的长期目标是了解艾滋病毒调节结核病潜伏期的机制，以及如何将这些机制用于治疗和预防目的。这项工作的目标是对HO-1和宿主生物能量学在结核病和艾滋病毒感染方面的作用产生详细的、机械性的理解。我们基于大量初步数据的中心假设是，艾滋病毒导致宿主细胞生物能量阈值的不平衡，这是由HO-1维持的，将平衡从潜伏的结核病转移到活跃的感染。我们的理由是，这项提议的成功完成将为我们的知识基础贡献缺失的HO-1依赖疾病功能的机械要素，如果没有这些基础知识，就不能完全理解结核病潜伏期和艾滋病毒介导的重新激活的机制。我们将应用实时代谢流量分析等新技术来非侵入性地测量感染Mtb和/或HIV的细胞的耗氧率(OCR)、胞外酸化率(ECAR)、备用呼吸量(SRC)、最大呼吸和ATP周转。这项强大的技术尚未被应用于细菌/病毒宿主相互作用的生物能量学研究。我们还将利用新型的HO-1转基因动物和人类结核病肺组织来准确描述HO-1在体内TB/HIV中的作用。此外，我们将检查南非健康的、潜伏的结核病、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况。我们认为，这项研究具有创新性，因为它通过应用新技术和独特的患者队列来检查HO-1和生物能量学，作为更好地了解结核病/艾滋病毒疾病的范例，代表了对现状的新的实质性偏离。这一贡献意义重大，因为它是结核病/艾滋病毒研究连续体的第一步，将(I)从基础和临床研究的角度对HO-1在调节艾滋病毒和结核分枝杆菌疾病中的作用提供深入的机制洞察，(Ii)表征结核病/艾滋病毒患者的“生物能量阈值”，以及(Iii)确定结核/艾滋病毒共同感染的细胞群体和人类肺肉芽肿中的细胞事件。总体而言，这些研究将为理解结核病和艾滋病毒在人类肺结核肺部的持久性提供新的基础。

 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.