Contribution of phospholipase A2 enzymes in the homeostasis of the immune system

背景 免疫系统区分自我和非我，防止外来生物或其他类型的侮辱损害身体。为了确保自身的动态平衡，多种机制严密地调节免疫系统。现在人们意识到，一个复杂的微生物生态系统，称为微生物区系，与哺乳动物共生，并调节免疫反应。在我们的NSERC项目中，我们考虑了降解磷脂的杀菌酶，称为磷脂酶A2(PLA2)，在免疫系统调节中的作用。 假设 更具体地说，在这个更新应用中，我们假设一种分泌形式的PLA2(SPLA2)，称为sPLA2 group IIA(sPLA2-IIA)，调节免疫系统的关键调节事件。我们将使用基因工程小鼠，我们将仔细检查sPLA2-IIA表达对小鼠免疫系统的影响。由于sPLA2-IIA是一种在粘膜中组成性表达的高效杀菌酶，我们将进一步研究它通过对宿主共生微生物的活性来调节免疫动态平衡的作用。 目标 为了进一步了解sPLA2在免疫中的作用机制，我们将研究以下目的： 1.检测sPLA2-IIA的表达对免疫稳态的影响 2.检测sPLA2-IIA的表达对小鼠正常菌群的影响 3.探讨sPLA2-IIA表达调节免疫稳态的机制(S) 科学方法 最近一代缺乏特定sPLA2亚型的小鼠提供了一种在体内剖析sPLA2功能的方法。我们想强调的是，这项提案的一个独特和强大的方面是我们可以用来进行分析的广泛的“工具”。这些包括大量的转基因小鼠品系，用于完整评估小鼠微生物区系的基于弹枪的质谱学方法，用于大数据分析的系统，一系列重组蛋白(天然和靶向突变)，量化sPLA2亚型表达的方法和二十烷类化合物。重要的是，PI和他的合作者团队在sPLA2、微生物组和免疫学方法方面拥有丰富的经验。 冲击 尽管sPLA2酶已被知道至少20年，但最近转基因和基因敲除小鼠的发展才刚刚开始允许描述它们对生理的贡献。这一独特的研究计划将揭示一种重要的sPLA2酶在免疫中的作用，考虑到它在微生物区系平衡中的作用。

BACKGROUND The immune system distinguishes the self from the non-self, preventing foreign organisms or other sort of insults from damaging the body. To ensure of its homeostasis, multiple mechanisms tightly regulate the immune system. It is now appreciated that a complex ecosystem of microorganisms, referred to as the microbiota, lives in symbiosis with mammals and modulates immune responses. In our NSERC program, we consider the role of bactericidal enzymes hydrolyzing phospholipids, called phospholipase A2 (PLA2), in the regulation of the immune system. HYPOTHESIS More specifically in this renewal application, we hypothesize that a secreted form of PLA2 (sPLA2), called sPLA2 group IIA (sPLA2-IIA), modulates key regulatory events of the immune system. We will use genetically engineered mice and we will scrutinize the impact of sPLA2-IIA expression on the immune system in mice. As sPLA2-IIA is a highly potent bactericidal enzyme constitutively expressed in mucosae, we will further consider its role on the regulation of immune homeostasis through its activity on the host’s commensal microbes. AIMS To gain further insight into sPLA2 mechanism of action in immunity, we will investigate these following aims: 1. To characterize the impact of expression of sPLA2-IIA on immune homeostasis 2. To determine the effect of the expression of sPLA2-IIA on the normal flora in mice 3. To examine mechanism(s) by which sPLA2-IIA expression modulates the immune homeostasis SCIENTIFIC APPROACH The recent generation of mice deficient in specific sPLA2 isoforms provides a method for dissection of sPLA2 functions in vivo. We wish to highlight that a unique and powerful aspect of this proposal is the extensive array of ‘tools’ available for our analyses. These include a substantial number of genetically modified mouse strains, shot-gun based mass-spectrometry approach for the complete assessment of mouse microbiota, systems for large data analysis, a series of recombinant proteins (native and targeted mutations), methods for quantifying sPLA2 isoform expression and eicosanoid species. Importantly, the PI and his team of collaborators have extensive experience with sPLA2, microbiome and immunologic approaches. IMPACT Although sPLA2 enzymes have been known for at least two decades, the recent development of transgenic and knockout mice is just starting to permit the delineation of their contribution to physiology. This unique research program will reveal the role of a prominent sPLA2 enzyme in immunity, considering its role in the equilibrium of the microbiota.