Understanding and leveraging immunometabolism to combat Clostridioides difficile infection

项目总结 这个应用程序的总体目标是更好地理解和利用组3固有淋巴细胞(ILC3)生物学 目的：增强对艰难梭状芽胞杆菌感染(CDI)的黏膜免疫应答。我们缺乏完全有效的 治疗这种病原体，迫切需要更好地了解艰难梭菌是如何与我们的 免疫系统。ILC3是一种罕见的免疫细胞，定位于粘膜组织中，有助于抵御细菌 感染，包括艰难梭菌。激活后，ILC3分泌高水平的细胞因子白介素22(IL-22) 它是炎症过程中组织反应的关键调节因子。我们最近发表的研究表明， 艰难梭菌的主要毒力因子B毒素(TcdB)直接激活ILC3s。此外，其他人的工作也有 在小鼠CDI模型中，给予重组IL-22提供了保护作用，这表明 在感染期间提高细胞因子的自然产生水平可以帮助CDI患者。因此，我们 正在研究ILC3中的分子途径对激活识别新的增强途径很重要 功能。其中一个非常有趣的途径家族是细胞新陈代谢。我们的初步数据显示， 多胺正向调节TcdB介导的ILC3的激活。被激活的人体内多胺水平升高 ILC3和当关键的生物合成酶被抑制时，ILC3产生的IL-22较少。多胺很重要 在转录和翻译中，在其他免疫细胞的激活中起着重要作用，但尚未完全 在ILC3中进行了调查。中心假设是多胺生物对ILC3的激活很重要，并且 多胺可用于改善艰难梭菌感染和/或复发的结果。在本建议书中 我们将研究代谢途径如何控制ILC3的激活，这对这些具有可翻译的含义 艰难梭菌感染中的免疫细胞。核心假设将通过追求两个具体目标来检验：1) 确定艰难梭菌激活的ILC3中多胺作用的机制(S)和2)确定如何 利用多胺生物学治疗原发和复发性CDI。在第一个目标下，我们将进行有针对性的和 用非靶向方法确定艰难梭菌介导的ILC3中多胺靶向的细胞途径(S) 激活。第二个目标将测试多胺如何在体内被靶向以增强先天免疫反应。 从而预防或降低原发或复发疾病的CDI严重程度。在完成这些目标后， 预期的结果是双重的，因为我们将(1)了解基础免疫学如何 多胺调节ILC3的激活和(2)决定多胺的翻译潜力 在CDI期间利用来增强免疫力。这些结果将对我们理解 艰难梭菌的免疫反应，因为它们将为进一步开发艰难梭菌提供强有力的循证理由 CDI患者的ILC3和IL-22生物靶向治疗。

PROJECT SUMMARY The overall goal of this application is to better understand and harness group 3 innate lymphocyte (ILC3) biology to enhance mucosal immune responses to Clostridioides difficile infection (CDI). We lack fully effective treatments for this pathogen and there is critical need to better understand how C. difficile interacts with our immune system. ILC3s are rare immune cells localized within mucosal tissues that help protect against bacterial infections, including C. difficile. Upon activation, ILC3s secrete high levels of the cytokine interleukin-22 (IL-22) which is a critical regulator of tissue responses during inflammation. Our recent published study shows that a major virulence factor of C. difficile, toxin B (TcdB), directly activates ILC3s. Furthermore, work from others has shown that administration of recombinant IL-22 provides protection in a mouse CDI model suggesting that boosting the cytokine over its naturally produced levels during infection could aid CDI patients. Therefore, we are investigating the molecular pathways in ILC3s important for activation to identify novel pathways to enhance function. One family of pathways of great interest is cellular metabolism. Our preliminary data show that polyamines positively regulate TcdB-mediated activation of ILC3s. Polyamine levels are increased in activated ILC3s and when the key biosynthesis enzyme is inhibited, ILC3s produce less IL-22. Polyamines are important in transcription and translation, have important roles in activation of other immune cells and have yet to be fully investigated in ILC3s. The central hypothesis is that polyamine biology is important for ILC3 activation, and polyamines can be leveraged for improving outcomes to C. difficile infection and/or recurrence. In this proposal we will examine how a metabolic pathway controls ILC3 activation, which has translatable implications on these immune cells in C. difficile infection. The central hypothesis will be tested by pursuing two specific aims: 1) Determine the mechanism(s) of polyamine function in C. difficile-activated ILC3s and 2) Determine how to leverage polyamine biology in primary and recurrent CDI. Under the first aim, we will undertake targeted and untargeted approaches to determine the cellular pathway(s) that polyamines target in C. difficile-mediated ILC3 activation. The second aim will test how polyamines can be targeted in vivo to boost the innate immune response and thereby prevent or reduce CDI severity in primary or recurrent disease. Upon completion of these aims, the expected outcomes are two-fold as we will (1) gain an understanding of fundamental immunology of how polyamines regulate ILC3 activation and (2) determine the translatable potential of how polyamines can be leveraged during CDI to boost immunity. These results will have a positive impact on our understanding of immune responses to C. difficile as they will provide strong evidence-based rationale for further development of ILC3 and IL-22 biology targeted therapies for CDI patients.