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， 感染、长期药物治疗方案和杀死巨噬细胞内的休眠杆菌。近距离接触后 对于患有肺结核的个体，大多数人发展成潜伏性结核杆菌感染（LTBI）。但也有 个体对感染具有天然抗性（RSTR）。耐药机制尚不清楚，可能 提供了对新的治疗策略的深入了解。在乌干达城市进行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仍然持续TST， 延长随访期间干扰素-γ释放试验（IGRA）阴性。据我们所知，这个大乌干达人 队列是唯一的，具有严格的纵向临床和流行病学数据。使用基因组富集和 结核分枝杆菌感染的外周血单核细胞RSTR中转录谱的网络分析 和LTBI组，我们发现组蛋白脱乙酰酶（HDAC）基因家族将RSTR与LTBI区分开来 并且可以调节对Mtb感染的抗性。我们在HIV-1未感染者中进行了全基因组连锁研究， （HIV-）RSTR在乌干达，并发现与这一重要的临床表型相关的基因座。外周 血液单核细胞衍生的和肺泡巨噬细胞，HDAC抑制剂治疗降低Mtb复制， 与未经处理的细胞相比。总之，这些数据支持我们的主要假设，即RSTR具有 保护性先天免疫应答，其是巨噬细胞依赖性和部分HDAC依赖性的。 然而，我们的知识有许多空白。首先，HDAC签名是基于网络的， 不知道它是否是RSTR表型的主要因果调节因子。第二，HDAC是一个11人的家庭 修饰染色质并调节转录、细胞内稳态和先天免疫的酶 对微生物的反应RSTR中HDAC依赖性通路改变的细节尚不清楚。 表观遗传学和蛋白质组学研究（包括乙酰化概况）可以解决这些差距。三、机制 HIV+个体中Mtb耐药的情况完全未知。由于艾滋病毒感染严重失调T- 细胞对Mtb的反应，HIV感染者（HIV+）可能更多地依赖于先天免疫来帮助控制Mtb 比未感染艾滋病毒的人（HIV-）。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 通过遗传学方法发现RSTR和LTBI之间不同的候选耐药基因和途径 HIV+和HIV-个体。在R33阶段（目标3），我们将使用细胞和体内方法来发现 耐药机制和这些途径的小分子抑制剂，可以发展为宿主 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.