A Novel Proteomic Approach to TB Biomarker Discovery using Human Exosomes

描述（由申请人提供）：活动性结核病（TB）的标准治疗方案年龄>40岁，疗效欠佳，因为它需要每天坚持服药？6个月，症状消失很久之后。现在，几十年来第一次，结核病药物管道充满了新的，高效的和可能缩短治疗时间的药物，接近准备进行2/3期临床试验。不幸的是，评估这些药物带来了重大挑战，因为需要大样本量（约2500例患者）和长随访期（约30个月）来证明它们在预防治疗失败和复发方面非劣效于标准方案。虽然两个月的分枝杆菌培养转化目前被用作替代标志物，但它有许多缺点，例如需要从不再咳嗽的患者收集痰液，将其运送到专业的参考实验室，并等待数周才能得到统计功效差的二分结果。 该提案的目的是使用靶向人类外泌体的蛋白质组学方法开发定量的、基于血液的TB生物标志物测定。外来体是宿主细胞在主动感染期间释放的囊泡纳米颗粒。与它们在免疫信号传导中的假定作用一致，外泌体含有高浓度的M。结核病（Mtb）蛋白，这似乎随着Mtb从感染小鼠中的清除而减少。因此，我们假设外泌体蛋白可以作为合适的生物标志物，用于在临床试验中随机分配到不同药物方案的组中以及在标准方案的个体中预测对TB治疗的微生物学反应。一种非痰液依赖性、非基于生长的生物标志物检测方法，可以在这两种情况中的一种或两种情况下的早期治疗中应用，这可能会改变结核病药物开发和全球结核病控制的步伐和范围。该测定也可用于监测在儿童TB、肺外TB和HIV-TB合并感染中常见的少杆菌病的治疗。 为了实现这一目标，我们组建了一个多学科的结核病研究人员团队，他们具有外泌体生物学、蛋白质组学、诊断学、新型预测方法和临床试验方面的专业知识。我们将建立在我的K23导师的NIH资助的肺炎队列研究的现有基础设施上，从患者中收集系列血清标本，然后进行培养确认的肺结核治疗的初始阶段。 我们将使用这些数据和样品来1）优化用于Mtb-生物标志物测定的处理血清外泌体的方法; 2）评估血清学的、基于外泌体的Mtb-生物标志物组响应于治疗的动力学，并确定用于评估该响应的最佳采样框架。在完成这些原理验证研究后，我们希望获得初步数据，以证明更大规模的临床研究的合理性， 在测试和验证队列中预测治疗反应的标志物;进一步开发和验证这些标志物的临床测试平台;并最终在目前正在开发的3期临床试验库中评估作为替代标志物的结果。

DESCRIPTION (provided by applicant): The standard treatment regimen for active tuberculosis (TB) is >40 years old and has suboptimal effectiveness, because it requires daily drug adherence for ?6 months, long after symptoms have resolved. Now, for the first time in decades, the TB drug pipeline is full of new, highly potent and possibly treatment- shortening agents nearing readiness for phase 2/3 clinical trials. Unfortunately, evaluating these drugs poses major challenges, because of the large sample sizes (~2500 patients) and long follow-up periods (~30 months) required to show their non-inferiority to the standard regimen in preventing treatment failure and relapse. Although two-month mycobacterial culture conversion is currently used as a surrogate marker, it has numerous disadvantages, such as the need to collect sputum from patients who are no longer coughing, transport it to specialized reference laboratories, and wait weeks for a dichotomous result which has poor statistical power. The objective of this proposal is to develop a quantitative, blood-based, TB biomarker assay using a proteomic approach that targets human exosomes. Exosomes are vesicular nanoparticles released by host cells during active infection. Consistent with their postulated role in immune signaling, exosomes contain high concentrations of M. tuberculosis (Mtb) proteins, which seem to decrease with clearance of Mtb from infected mice. Thus, we hypothesize that exosome proteins can serve as suitable biomarkers for predicting microbiologic response to TB treatment among groups randomized to different drug regimens in clinical trials, as well as among individuals on standard regimens. A non-sputum-dependent, non-growth-based biomarker assay that could be applied early in treatment in either or both of these scenarios could transform the pace and scope of TB drug development and global TB control. This assay would also be useful for monitoring treatment of paucibacillary disease as is common in childhood TB, extrapulmonary TB, and HIV-TB co-infection. To achieve this goal, we have assembled a multidisciplinary team of TB researchers with expertise in exosome biology, proteomics, diagnostics, novel prediction methods, and clinical trials. We will build on the existing infrastructure of my K23 mentor's NIH-funded cohort study of pneumonia by collecting serial serum specimens from patients followed through the initiation phase of treatment for culture-confirmed pulmonary TB. We will use these data and samples to 1) optimize methods for processing serum exosomes for Mtb- biomarker assays; 2) evaluate the kinetics of a serologic, exosome-based Mtb-biomarker panel in response to treatment, and determine the optimal sampling frame for assessing that response. Upon completing these proof-of-principle studies, we expect to have the preliminary data to justify larger clinical studies to determine the accuracy of the marker in predicting treatment response in test and validation cohorts; to further develop and validate a clinical testing platform for these markers; and ultimately to evaluate the resultin refined assay as a surrogate marker in Phase 3 clinical trial banks currently under development.