Discovery of novel, ubiquitin-regulated mechanisms of TB control by macrophages

 描述（由申请人提供）：由结核分枝杆菌感染引起的结核病（TB）仍然是人类发病率和死亡率的主要原因，特别是在发展中国家。慢性M.结核病感染需要细菌和宿主免疫系统之间的长期相互作用，而组织巨噬细胞在感染的结果中起着关键作用。尽管监测宿主基因表达的全球变化的技术已经促进了我们对TLR激活和干扰素在TB感染期间的重要作用的理解，但转录的调节仅代表对细菌感染的许多细胞反应之一。蛋白质的翻译后修饰，如泛素化、磷酸化和乙酰化，在几乎所有的细胞内都起着调节作用。 过程这些信号事件如何导致在细菌感染期间观察到的代谢途径、自噬和囊泡运输的变化仍然未知。此外，病原体如何操纵这些过程对于理解微生物的致病策略至关重要。该提案旨在使用强大的新蛋白质组学技术来全面量化泛素化的变化，以确定新的功能性巨噬细胞对M。肺结核感染。我们利用这种方法的初步实验已经揭示了宿主蛋白质泛素化响应细胞内病原体的深刻变化。这些研究首次揭示了先天免疫应答过程中大量未知的翻译后修饰。我们的假设是，这些变化通过控制自噬、代谢、蛋白质降解和信号传导，在塑造随后的先天感染反应中发挥着重要作用，并且可能被病原体操纵以获得自身利益。我们的初步遗传学工作表明，新的途径是由感染过程中的泛素化控制，并能够限制M。结核菌在巨噬细胞中的生长，进一步验证了这种方法发现新生物学的能力。最终，我们的长期目标是利用这些强大的免疫机制用于治疗目的。

 DESCRIPTION (provided by applicant): Tuberculosis (TB), caused by infection with Mycobacterium tuberculosis, remains a major cause of human morbidity and mortality, particularly in the developing world. Chronic M. tuberculosis infection requires long- term interactions between the bacterium and host immune system, and tissue macrophages play key roles in the outcome of infection. Although technologies to monitor global changes in host gene expression have catalyzed our understanding of the important roles for TLR activation and interferon during TB infection, modulation of transcription represents only one of many cellular responses to bacterial infection. Post- translational modification of proteins, such as ubiquitylation, phosphorylation, and acetylation play a role in regulating virtually every cellular process. How these signaling events lead to observed changes in metabolic pathways, autophagy, and vesicular trafficking during bacterial infection remain unknown. Furthermore, how these processes may be manipulated by pathogens is crucial for understanding the pathogenic strategies of microorganisms. This proposal seeks to use powerful new proteomic technologies to globally quantify changes in ubiquitylation in order to identify novel functional macrophage responses to M. tuberculosis infection. Our preliminary experiments utilizing this approach have uncovered profound changes in host protein ubiquitylation in response to intracellular pathogens. These studies have provided the first glimpse into a vast unknown of post-translational modifications during innate immune responses. Our hypothesis is that these changes play fundamental roles in shaping the subsequent innate responses to infection by controlling autophagy, metabolism, protein degradation, and signaling, and may be manipulated by pathogens for their own benefit. Our preliminary genetic work indicates that novel pathways are controlled by ubiquitylation during infection and are capable of restricting M. tuberculosis growth in macrophages, further validating the power of this approach to uncover new biology. Ultimately, our long-term goal is to harness these powerful immune mechanisms for therapeutic purposes.