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

免疫系统区分自我与非自我，防止外来生物或其他种类的侮辱损害身体。为了保证免疫系统的稳态，多种机制对免疫系统进行了严密的调控。现在人们认识到，一个复杂的微生物生态系统，称为微生物群，与哺乳动物共生并调节免疫反应。在我们的NSERC计划中，我们考虑了水解磷脂的杀菌酶，称为磷脂酶A2 (PLA2)，在免疫系统调节中的作用。更具体地说，在这个更新应用中，我们假设PLA2 （sPLA2）的一种分泌形式，称为sPLA2组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，我们将仔细研究sPLA2-IIA表达对小鼠免疫系统的影响。由于sPLA2-IIA是一种高效的在粘膜中组成表达的杀菌酶，我们将进一步考虑其通过对宿主共生微生物的活性来调节免疫稳态的作用。******AIMS***为了进一步了解sPLA2在免疫中的作用机制，我们将研究以下目标：******1。表征sPLA2-IIA表达对免疫稳态的影响***2。测定sPLA2-IIA表达对小鼠正常菌群的影响***3。为了研究sPLA2- iia表达调节免疫稳态的机制******科学方法******最近一代sPLA2亚型缺乏的小鼠为体内sPLA2功能的解剖提供了一种方法。我们希望强调的是，这项建议的一个独特而有力的方面是，我们可以使用广泛的工具进行分析。其中包括大量的转基因小鼠菌株，用于小鼠微生物群完整评估的基于霰弹枪的质谱方法，用于大数据分析的系统，一系列重组蛋白（天然和靶向突变），用于定量sPLA2异构体表达和类二十碳酸盐物种的方法。重要的是，PI和他的合作者团队在sPLA2，微生物组和免疫方法方面拥有丰富的经验。******影响***尽管sPLA2酶已经被发现了至少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学的贡献。这项独特的研究计划将揭示sPLA2酶在免疫中的重要作用，考虑到它在微生物群平衡中的作用。**************

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. **************