Persistent DNA Hyper-Methylation of the IFN-γ Signaling Pathway During Tuberculosis

项目概要： 结核病（TB）是世界上导致死亡和痛苦的主要传染病。 现有的“短期”治疗持续六个月的折磨，病死率为3%， 在结核病高度流行的国家，这一比例为>20%，在耐多药结核病的情况下，这一比例为> 30%。的 孟德尔分枝杆菌病易感性（MSMDs）是一种罕见的基因突变， 免疫系统的IFN-γ信号通路上游或下游。众所周知，结核病 破坏宿主的免疫控制，但它这样做的多种机制仍然是完全 阐明。 我们的初步数据表明，结核病通过诱导 IFN-γ信号通路上游和下游的DNA超甲基化，类似于MSMD 突变。此外，我们的初步数据表明，来自研究参与者的免疫细胞， TB降低了IFN-γ诱导基因表达的上调，从而模拟了IFN-γ诱导基因表达的功能。 IFNGR、STAT 1和IRF 1的下游MSMD突变中观察到缺陷。我们的初步 生物信息学分析表明，IFN-γ诱导基因表达的抑制发生在 通过表观遗传抑制a）经典IFN-γ信号传导途径，B）转录因子和c） 非经典信号通路。 使用现有的生物储存库，我们将评估典型IFN-γ的DNA甲基化， 信号通路以及重叠和交织的非经典信号通路。我们将 通过评估去甲基化剂是否能够逆转DNA， 在一些实施方案中，IFN-γ信号传导途径的甲基化可以被抑制，并且恢复IFN-γ诱导型基因表达。我们将 对1）无症状家庭接触者，2）肺部感染者， 治疗成功的肺结核和治疗失败的肺结核。 阐明结核病破坏宿主免疫的表观遗传机制是一个必要的研究课题。 在开发改进的治疗监测工具和开发辅助宿主定向 免疫疗法，以改善临床结果。拟议的科学和指导将有 申请人准备成功过渡到一个独立的研究人员。

PROJECT SUMMARY: Tuberculosis (TB) is the world’s leading infectious disease cause of mortality and suffering. Existing “short-course” therapy lasts six grueling months and has case fatality rates of 3% that increase to >20% in TB hyper-endemic countries and > 30% in the setting of multi-drug resistant TB. The Mendelian Susceptibility to Mycobacterial Disease (MSMDs) are rare genetic mutations that perturb the immune system either up or down-stream of the IFN-γ signaling pathway. It is well known that TB subverts host immune control, however the multiple mechanisms it does so remain to be fully elucidated. Our preliminary data demonstrate that TB epigenetically subverts host immunity by inducing DNA hyper-methylation both up and down-stream of the IFN-γ signaling pathway, akin to the MSMD mutations. Further, our preliminary data demonstrates that immune cells from study participants with TB have decreased up-regulate of IFN-γ-inducible gene expression, thereby mimicking the functional defect seen in the down-stream MSMD mutations in IFNGR, STAT1, and IRF1. Our preliminary bioinformatics analysis demonstrates that the inhibition of IFN-γ-inducible gene expression occurs through epigenetic inhibition of a) the canonical IFN-γ signaling pathway, b) transcription factors and c) non-canonical signaling pathways. Using an existing biorepository, we will evaluate the DNA methylation of the canonical IFN-γ signaling pathway as well as overlapping and intertwined non-canonical signaling pathways. We will functionally validate these results by evaluating if de-methylating agents are able to reverse DNA hyper-methylation of the IFN-γ signaling pathway and restore IFN-γ inducible gene expression. We will longitudinally perform these analyses on adults with 1) asymptomatic household contacts, 2) pulmonary TB with treatment success and 3) pulmonary TB with treatment failure. The elucidation of epigenetic mechanisms by which TB subverts host immunity is a necessary step in developing improved treatment monitoring tools and the development of adjunct host directed immunotherapy to improve clinical outcomes. The proposed science and mentorship will have the applicant poised for successful transition to an independent researcher.