M. tuberculosis metabolites to activate human mucosal-associated invariant T cells

结核分枝杆菌(Mtb)感染了全球四分之一以上的人口，仍然是一种重要的健康问题。 每年造成数百万人死亡的威胁。结核分枝杆菌的多药耐药性导致治疗失败的风险更高 和死亡。世界范围内的高结核病负担要求发现新的细胞和分子 制定有效保护战略的目标。已知粘膜相关不变量T(MAIT) 细胞对非肽类细菌代谢物作出反应，并作为先天的感受器来激发快速免疫 对结核分枝杆菌感染的反应。Mtb感染中MAIT细胞的激活需要Mtb代谢物的识别 由单态抗原呈递分子以个体不受限制的方式呈递的抗原，类似 病原体相关分子模式与先天受体的结合。预计将激活MAIT电池 在早期或慢性结核病感染时诱导快速抗结核分枝杆菌MAIT细胞反应。尽管最近的研究 提供了强有力的证据支持MAIT细胞对小鼠和人类结核病的保护作用， 来自大肠杆菌的模型抗原在小鼠和灵长类动物中诱导部分保护作用，并对某些动物产生副作用。 其他灵长类受试者。抗结核分枝杆菌大肠杆菌抗原诱导的次优保护性MAIT细胞反应 感染可能是因为结核分枝杆菌提供不同的抗原来激活和识别MAIT细胞或潜在的 大肠杆菌化合物的毒性作用。事实上，MAIT细胞对各种病原体的反应是不同的，目前 关键的未知是哪些结核分枝杆菌抗原刺激抗结核分枝杆菌MAIT细胞反应。基于我们经过验证的 功能代谢组学平台，我们将应用这些化学生物学方法来测试中央 假设结核分枝杆菌代谢产物刺激人类MAIT细胞对结核分枝杆菌感染的反应有两个目的。在……里面 目的1，我们将使用我们的纯化和初步鉴定的结核分枝杆菌激动剂来诱导保护性的抗结核分枝杆菌反应。 多克隆和单克隆人MAIT细胞与大肠杆菌抗原的比较。MTB激动剂将刺激 来自健康捐献者、结核病患者和肺组织的MAIT细胞。MAIT细胞反应的保护 将主要通过杀死结核分枝杆菌感染细胞和抑制结核分枝杆菌生长来衡量。在目标2中，我们将确定 利用功能代谢组学刺激抗结核分枝杆菌MAIT细胞反应的结核分枝杆菌激动剂的化学结构。 我们用高压液相色谱分离得到了MAIT刺激组分，并鉴定了 激活MAIT细胞的候选MTB激动剂。我们基于质谱学的功能代谢组学将 进一步从活性化学部分确定Mtb激动剂的结构。产生了新的结核分枝杆菌代谢物 将通过化学合成或提纯来激活MAIT细胞并保护其免受结核分枝杆菌感染。 成功完成后，我们将阐明Mtb代谢物的结构和功能，以诱导 针对结核病感染的保护性MAIT细胞反应。最终，结核分枝杆菌抗原可以应用于 了解MAIT在结核病中的激活机制并开发新型抗分枝杆菌药物 抗击人类结核病的策略。

Mycobacterium tuberculosis (Mtb) infects over a quarter of the global population and remains a significant health threat causing millions of deaths annually. Multidrug resistance of Mtb leads to a higher risk of failed treatment and death. This high tuberculosis burden worldwide demands the discovery of novel cellular and molecular targets for developing efficacious protective strategies. It is known that mucosal-associated invariant T (MAIT) cells respond to non-peptidic bacterial metabolites and function as innate-like sensors to elicit rapid immune responses against Mtb infections. MAIT cell activation in Mtb infection requires the recognition of Mtb metabolite antigens presented by a monomorphic antigen-presenting molecule in an individual-unrestricted manner, similar to the binding of pathogen-associated molecular patterns to innate receptors. Activated MAIT cells are expected to induce rapid anti-Mtb MAIT cell responses at early or chronic tuberculosis infections. Although recent studies provided strong evidence supporting the protective role of MAIT cells against tuberculosis in mice and humans, the model antigen from E. coli induced partial protection in mice and primates, together with side effects in some other primate subjects. This suboptimal protective MAIT cell response induced by the E.coli antigen against Mtb infection is likely because Mtb provides different antigens to activate and recognize MAIT cells or the potential toxic effect of the E. coli compound. Indeed, MAIT cells respond differently to various pathogens, and the current critical unknown is which Mtb antigens stimulate anti-Mtb MAIT cell responses. Based on our validated functional metabolomics platform, we will apply these chemical biology approaches to test the central hypothesis that Mtb metabolites stimulate human MAIT cell response against Mtb infections with two aims. In Aim 1, we will use our purified and preliminarily identified Mtb agonists to induce protective anti-Mtb responses of polyclonal and monoclonal human MAIT cells in comparison with the E. coli antigen. Mtb agonists will stimulate MAIT cells from healthy donors, tuberculosis patients, and lung tissues. The protection of MAIT cell responses will be mainly measured by killing Mtb-infected cells and inhibiting Mtb growth. In Aim 2, we will determine the chemical structures of Mtb agonists using functional metabolomics to stimulate anti-Mtb MAIT cell responses. We have obtained MAIT-stimulatory fractions using high-pressure liquid chromatography and identified candidate Mtb agonists that activated MAIT cells. Our mass spectrometry-based functional metabolomics will further define the structures of Mtb agonists from active chemical fractions. Resulted in novel Mtb metabolites will be either chemically synthesized or purified for MAIT cell activation and protection against Mtb infections. Upon successful completion, we will elucidate the structures and functions of Mtb metabolites to induce a protective MAIT cell response against tuberculosis infections. Ultimately, Mtb antigens can be applied to understand MAIT activation mechanisms in tuberculosis disease and develop novel anti-mycobacterial strategies for fighting tuberculosis in humans.