Dual Targeting of Mtb Resistance Mechanisms

摘要 结核分枝杆菌(Mtb)是人类结核病的病原体，目前导致近 每年有170万人死亡。结核病控制受到耐药结核分枝杆菌菌株持续出现的威胁。 现在已经观察到对所有结核病药物的临床耐药性，突显出迫切需要的不仅仅是新的 药物，但对于直接靶向并使耐药性机制失效的全新策略。其中两个 在结核病治疗中防止出现抗生素耐药性的最有希望的策略是 针对耐药、不可复制的细菌群体和宿主定向治疗(HDT)。我们确定了一个 一系列具有体外抗复制和非复制结核分枝杆菌活性的类药物ATP类似物 与利福平相比，利福平是针对非复制结核杆菌的一线药物之一。因为这些抑制剂是 最初是为抑制人转化生长因子受体(转化生长因子βR)而开发的，这是一种 与结核病免疫有关，我们还试图测试抑制转化生长因子β受体是否介导宿主导向的活动 针对结核分枝杆菌。我们发现，转化生长因子βR的基因缺失和化学抑制显著减少了细菌 装入受感染的动物体内。我们发现，缺乏转化生长因子β受体的T细胞在 与结核杆菌感染的巨噬细胞同源，并在感染的肺部部位产生干扰素γ。这些 初步研究提出了一个新的答案，即为什么T细胞对结核分枝杆菌的反应是 在感染部位不充分，突出了转化生长因子β信号转导可能是新的HDT靶点。因此， 我们确定了具有两种独立活性的化合物，它们都能杀死结核分枝杆菌，并可能阻碍结核杆菌的出现。 抗药性。利用遗传学和三磷酸腺苷类似物作为化学工具，我们将识别细胞中的结核分枝杆菌靶标。 负责直接杀死结核分枝杆菌，从而确定药物耐受性的新靶点。在东道主方面，我们 将确定转化生长因子β受体信号在结核分枝杆菌感染中的作用。最后，我们将测试这种双重宿主-病原体靶向 通过测试我们的化合物在体内的有效性来制定战略。

ABSTRACT Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB) in humans, currently leads to nearly 1.7 million deaths a year. TB control is threatened by the continued emergence of drug-resistant Mtb strains. Clinical resistance has now been observed against all TB drugs, underscoring the urgent need not just for new drugs, but for entirely new strategies that directly target and disable drug resistance mechanisms. Two of the most promising strategies to prevent the emergence of antibiotic resistance in the treatment of TB are the targeting of drug tolerant, non-replicating bacterial populations and host-directed therapy (HDT). We identified a series of drug-like ATP analogs with in vitro activity against replicating and non-replicating Mtb that is comparable to that of rifampicin, one of the first-line drugs targeting non-replicating Mtb. Because these inhibitors were originally developed for the inhibition of the human transforming growth factor receptor (TGFβR), a pathway implicated in immunity to TB, we also sought to test whether inhibition of TGFβR mediates host-directed activity against Mtb. We found that genetic deletion and chemical inhibition of TGFβR significantly reduced the bacterial load in infected animals. We showed that T-cells lacking TGFβR had an increased capacity to interact in a cognate manner with Mtb-infected macrophages and produce IFNγ at the pulmonary site of infection. These preliminary studies suggest a new answer to the longstanding question why the T cell response to Mtb is inadequate at the site of infection and highlights the possibility that TGFβ signaling is a new HDT target. Thus, we identified compounds that have two independent activities that both kill Mtb and likely impede the emergence of drug resistance. Using genetics and the ATP analogs as chemical tools, we will identify the cellular Mtb targets responsible for directly killing Mtb, thus identifying new targets that underlie drug tolerance. On the host side, we will determine the role of TGFβR signaling in Mtb infection. Lastly, we will test this dual host-pathogen targeting strategy by testing the efficacy of our compounds in vivo.