Epigenetic & Post-Translational Mechanisms of Macrophage Resistance to Mycobacterium tuberculosis During HIV Co-Infection

控制结核病(TB)的障碍包括缺乏高效疫苗，预防 感染，长期药物治疗方案，以及杀死巨噬细胞内的休眠细菌。近距离接触后 对于患有肺结核病的个人，大多数人会患上潜伏的结核分枝杆菌感染(LTBI)。然而，一些人 个体天生对感染具有抵抗力(RSTR)。抗药性的机制尚不清楚，可能 提供对新治疗策略的洞察。在乌干达城市的一项大型结核病家庭接触研究中 在过去的20年里，我们发现约9%的密切成年家庭接触者持续存在TST和TST 延长随访期间干扰素-γ释放试验(IGRA)为阴性。据我们所知，这个大型乌干达人 队列是独一无二的，具有严格的纵向临床和流行病学数据。利用基因集浓缩和 RSTR中结核分枝杆菌感染的外周血单核细胞转录谱的网络分析 和LTBI组，我们发现组蛋白脱乙酰酶(HDAC)基因家族区分了RSTR和LTBI 并可能调节对结核分枝杆菌感染的抵抗力。我们对未感染的HIV-1病毒进行了全基因组连锁研究 (HIV-)RSTR，并发现了与这一重要临床表型相关的基因。在外围设备中 血单核细胞和肺泡巨噬细胞，HDAC抑制剂治疗降低MTB复制 与未经处理的细胞进行比较。总之，这些数据支持我们的主要假设，即RSTR具有 依赖巨噬细胞和部分依赖HDAC的保护性先天免疫反应。 然而，我们的知识中有许多空白。首先，HDAC签名是基于网络的，我们确实是这样做的 不知道它是否是RSTR表型的主要原因调节因子。其次，HDAC是一个11口之家 修饰染色质和调节转录、细胞内稳态和先天免疫的酶 对微生物的反应。RSTR中哪些依赖HDAC的通路被改变的细节尚不清楚。 表观遗传学和蛋白质组学研究(包括乙酰化图谱)可以弥补这些差距。三、机制 HIV+个体对结核分枝杆菌的耐药性是完全未知的。由于HIV感染严重失调T-T- 艾滋病毒感染者(HIV+)对结核分枝杆菌的细胞反应可能更多地依赖于天然免疫来帮助控制结核分枝杆菌 比未感染艾滋病毒(HIV-)的人更多。在R61阶段(目标1和2)，我们将使用表观遗传学、蛋白质组学和 用遗传学方法发现RSTR和LTBI之间不同的候选抗性基因和途径 HIV+和HIV-个人。在R33阶段(目标3)，我们将使用细胞和体内方法来发现 这些途径的抗性机制和小分子抑制剂可以作为宿主开发 定向治疗。

Hurdles for controlling tuberculosis (TB) include the lack of a highly efficacious vaccine, prevention of infection, long drug treatment regimens, and killing dormant bacilli within macrophages. After close contact with an individual with pulmonary TB, most people develop latent Mtb infection (LTBI). However, some individuals are naturally resistant to infection (RSTRs). The mechanisms of resistance are unknown and may provide insight into novel therapeutic strategies. In a large TB household contact study in urban Uganda over the past 20 years, we found that ~9% of close adult household contacts remained persistently TST and Interferon-γ Release Assay (IGRA) negative during extended follow-up. To our knowledge, this large Ugandan cohort is unique with rigorous longitudinal clinical and epidemiologic data. Using gene-set enrichment and network analyses of transcriptional profiles of Mtb-infected peripheral blood-derived monocytes in the RSTR and LTBI groups, we found that the histone deacetylase (HDAC) gene family distinguishes RSTRs from LTBIs and may regulate resistance to Mtb infection. We performed a genome-wide linkage study in HIV-1 uninfected (HIV-) RSTRs in Uganda and discovered loci associated with this important clinical phenotype. In peripheral blood monocyte-derived and alveolar macrophages, HDAC inhibitor treatment decreased Mtb replication in comparison to untreated cells. Together, these data support our primary hypotheses that RSTRs have protective innate immune responses that are macrophage-dependent and partially HDAC-dependent. However, there are many gaps in our knowledge. First, the HDAC signature was network-based and we do not know if it is the major causal regulator of the RSTR phenotype. Second, HDACs are a family of 11 enzymes which modify chromatin and regulate transcription, cellular homeostasis, and the innate immune response to microbes. The details of which HDAC-dependent pathways are altered in RSTRs are unknown. Epigenetic and proteomic studies (including acetylation profiles) can address these gaps. Third, mechanisms of Mtb resistance in HIV+ individuals are completely unknown. Since HIV infection profoundly dysregulates T- cell responses to Mtb, HIV infected (HIV+) persons likely depend more on innate immunity to help control Mtb than HIV uninfected (HIV-) persons. In the R61 phase (Aim 1 and 2), we will use epigenetic, proteomic, and genetic approaches to discover candidate resistance genes and pathways that differ between RSTR and LTBI HIV+ and HIV- individuals. In the R33 phase (Aim 3), we will use cellular and in vivo approaches to discover mechanisms of resistance and small molecular inhibitors of these pathways that could be developed as host directed therapies.