Group V Phospholipase A2 and Pulmonary Inflammation

描述（由申请人提供）：本申请的总体目标是了解一种称为分泌型V族磷脂酶A2 （sPLA2）的酶的生物学功能，特别是它与控制感染和肺部炎症有关。V组sPLA2在肥大细胞和巨噬细胞中显著表达，这些细胞对于感知有害生物进入体内的部位和产生急性炎症反应至关重要，而急性炎症反应对于有效清除和杀死这些肺部病原体至关重要。V组sPLA2调节肥大细胞和巨噬细胞中白三烯和前列腺素的产生，以响应入侵病原体的替代品，即酵母菌，来源于酵母细胞壁，以及toll样受体(TLR)-2的激动剂。我们的早期研究表明，在TLR2刺激肥大细胞时，该酶调节肺巨噬细胞中白色念珠菌的吞噬和杀伤以及称为丝裂原活化蛋白激酶的信号分子的激活。因此，本提案的目的是了解V组sPLA2如何调节真菌的吞噬和杀伤；了解V组sPLA2如何调节肥大细胞中的TLR信号；并确定该酶对产生肺部炎症反应以抵抗入侵微生物及其从宿主中清除的重要性。为了实现这些目标，我们将比较缺乏V组sPLA2的巨噬细胞和正常巨噬细胞在酶酶酶刺激后的脂质产生和早期信号事件。我们将在巨噬细胞中表达正常和突变形式的V组sPLA2，以研究该酶的结构与其功能之间的关系。我们将比较缺乏V组sPLA2的肥大细胞和正常肥大细胞在TLR2刺激下产生的脂质和早期信号事件。我们将研究通过TLR2刺激的V组sPLA2在肥大细胞中的亚细胞定位。最后，我们将使用缺乏V组sPLA2的小鼠来研究这些发现在真菌肺部感染模型中的相关性。肺是传染性生物进入人体的主要部位。对这些生物体进行有效和适当的炎症反应的能力对生存至关重要。拟建的研究将明确V族磷脂酶A2在宿主防御中的功能。它们将为这种酶的功能提供新的信息，目前人们对这种酶的功能知之甚少。这些研究将为肺部炎症和先天免疫的调控提供新的见解。

DESCRIPTION (provided by applicant): The broad goal of this application is to understand the biological function(s) of an enzyme termed secretory group V phospholipase A2 (sPLA2), particularly as it pertains to control of infections and pulmonary inflammation. Group V sPLA2 is prominently expressed in mast cells and macrophages, cells that are critical for sensing harmful organisms at their sites of entry into the body and in generating the acute inflammatory response that is essential for efficient clearing and killing of these pulmonary pathogens. Group V sPLA2 regulates the generation of leukotrienes and prostaglandins in both mast cells and macrophages in response to stimuli that are surrogates for invading pathogens, namely zymosan, derived from yeast cell walls, and agonists of toll-like receptor (TLR)-2. Our early studies indicate that the enzyme regulates phagocytosis and killing of the yeast Candida albicans in pulmonary macrophages and activation of signaling molecules called mitogen-activated protein kinases in response to TLR2 stimulation of mast cells. The aims of this proposal are therefore to understand how group V sPLA2 regulates phagocytosis and killing of fungi; to understand how group V sPLA2 regulates TLR signaling in mast cells; and to determine the importance of the enzyme for generation of pulmonary inflammatory responses to invading microorganisms and their clearance from the host. To achieve these aims we will compare the generation of lipids and early signaling events following zymosan stimulation between macrophages that lack group V sPLA2 and normal macrophages. We will express normal and mutant forms of group V sPLA2 in macrophages to examine the relationship between the structure of the enzyme and its function. We will compare the generation of lipids and early signaling events in response to TLR2 stimulation between mast cells that lack group V sPLA2 and normal mast cells. We will study the subcellular location of group V sPLA2 in mast cells stimulated through TLR2. Finally, we will use mice that lack group V sPLA2 to study the relevance of these findings in models of fungal pulmonary infection. The lung is a major site of entry into the body for infectious organisms. The ability to mount an effective and appropriate inflammatory response to these organisms is essential for survival. The proposed studies will define the function of group V phospholipase A2 in host defense. They will provide new information on the function of this enzyme, which is presently poorly understood. These studies will provide new insight into the regulation of pulmonary inflammation and innate immunity.