Post-translational modifications of proteins in neutrophil immune responses

我的研究计划的长期目标是了解中性粒细胞如何促进免疫反应。NSERC-DG项目重点关注翻译后修饰对中性粒细胞蛋白功能的直接（目标1）和间接（目标2）作用。中性粒细胞负责对入侵病原体的初始反应。中性粒细胞形成储存在细胞内的蛋白质，其在刺激时迅速释放（脱粒）。这些蛋白质主要通过其有效的、短暂的酶活性发挥作用。蛋白质的翻译后修饰（PTM）是导致蛋白质功能变化的单个氨基酸改变，代表了维持蛋白质稳态的一种优雅方法。中性粒细胞可以诱导许多这些变化，特别是当它们遇到病原体时。由中性粒细胞介导的PTM的一个例子是瓜氨酸，其改变了称为精氨酸的氨基酸。这种修饰导致氨基酸电荷的变化，这可能对蛋白质折叠和最终功能的方式产生重大影响。 免疫反应的调节发生在许多不同的水平。例如，基因转录可以通过蛋白质（转录因子）或通过修饰DNA结构（表观遗传学）来改变。在蛋白质翻译后，PTM可以发挥类似的作用，但是免疫细胞通过PTM调节其免疫反应的精确变化还不清楚。 我们将研究中性粒细胞如何引入蛋白质改变以有效地中和病原体。所提出的方法使用重组中性粒细胞蛋白，然后将其暴露于促进PTM的条件下，然后使用基于活性的蛋白质组学来分析功能的改变。使用位点特异性质谱分析关键改变。此外，我们将确定修饰的中性粒细胞蛋白质可以促进与其他免疫细胞或蛋白质的串扰的机制。 我的NSERC-DG计划旨在利用蛋白质组学方法揭示新的免疫机制。这是研究免疫系统的一种新方法。从这个提议中产生的基础知识将为我提供机会，在跨学科技术中培训HQP，并提高对中性粒细胞用于中和病原体，与其他细胞沟通，并最终介导炎症以保护宿主的机制的理解。这项工作的影响将在免疫学家和生物化学家中感受到，他们也旨在了解蛋白质组学改变，在这种情况下，在中性粒细胞蛋白质上产生的改变，如何影响酶的功能。从这个程序产生的结论将提供新的见解分子改变如何帮助维持细胞外环境和保护宿主。我计划培养1名硕士生，1名博士生和5名本科生。

The long-term objective of my research program is to understand how neutrophils facilitate the immune response. The NSERC-DG program focuses on the direct (Obj 1) and indirect (Obj 2) role of post-translational modifications on neutrophil protein function. Neutrophils are responsible for the initial response to an invading pathogen. Neutrophils form proteins that are stored within the cell that are released rapidly upon stimulation (degranulation). These proteins function primarily through their potent, short-lived enzymatic activity. Post-translational modifications (PTM) of proteins are single amino-acid alterations that leads to functional changes in proteins and represent an elegant method of maintaining protein homeostasis. Neutrophils can induce many of these changes, particularly when they encounter pathogens. An example of a PTM that is mediated by neutrophils is citrullination, which alters an amino acid called arginine. This modification leads to a change in the charge of the amino acid, which can have significant impact on the way a protein folds and ultimately functions. Regulation of the immune response occurs at many different levels. For example, gene transcription can be altered through proteins (transcription factors) or by modifying the structure of DNA (epigenetics). After protein translation, PTMs can play a similar role, however the precise changes that immune cells use to tune their immune responses via PTMs are not well understood. We will investigate how neutrophils introduce protein alterations to efficiently neutralize pathogens. The proposed methods use recombinant neutrophil proteins, which are then exposed to conditions that facilitate PTMs, activity-based proteomics is then used to profile alterations in function. Key alterations are profiled using site-specific mass spectrometry. In addition, we will determine the mechanisms by which modified neutrophil proteins can facilitate crosstalk with other immune cells or proteins. My NSERC-DG program aims to uncover novel immunological mechanisms using proteomic approaches. This is representative of a new approach to studying the immune system. Fundamental knowledge generated from this proposal will provide opportunities for me to train HQP in interdisciplinary techniques and enhance the understanding of the mechanisms that neutrophils use to neutralize pathogens, communicate with other cells, and ultimately mediate inflammation to protect the host. The impact of this work will be felt amongst immunologists and biochemists, who also aim to understand how proteomic alterations, in this case those generated on neutrophil proteins, impacts the functionality of enzymes. Conclusions generated from this program will offer new insights into how molecular alterations help maintain the extracellular environment and protection of the host. I plan to train 1 MSc student, 1 PhD student and 5 undergraduate students in this cycle of my program.