T. cruzi: pathogenesis modulation by eicosanoids

描述（申请人提供）：二十烷酸是健康和疾病中心血管系统的重要介质。恰加斯型心肌病是世界上许多流行地区心血管疾病的最重要病因之一。感染克氏锥虫引起这种疾病，它具有许多与某些类二十烷（如血栓素）的影响相似的特征。这种感染导致炎症级联反应的激活。它还引起血管收缩、血小板聚集和平滑肌细胞增殖。我们的初步数据表明，宿主血栓素前列腺素受体（TP）的离散信号通路调节着宿主与寄生虫的关系。在TP敲除（KO）和WT小鼠分离的内皮细胞（ECs）中，我们发现TP-KO ECs中突变TP的表达可以作为解剖细胞内寄生虫生长的分子调控的一种方法。我们证明了G- α q或G- α 11在一定程度上控制了细胞内寄生虫的生长。我们将进行额外的实验来证实这些途径直接负责宿主TP抑制寄生虫的生长，从而确定第二信使影响寄生虫生长的机制。待检测的终点包括这些细胞对这种寄生虫的易感性、粘附和渗透、寄生虫生长和G α -q的下游信号通路。从各种常规和KO小鼠中获得的ECs将用于确定这种感染发病机制的重要途径。除内皮细胞外的其他细胞也有TP，但在我们的研究中，我们使用小鼠心脏内皮细胞，因为它们容易获得，易于转染并保持其表型。其他类型的细胞，如小鼠心肌细胞，很难以纯形式获得，并且在培养中不能保持其表型。因此，ECs作为所有TP细胞的替代物，是表征TP信号传导效应的模型。类二十烷途径的不同部分被删除的小鼠将被用于评估在恰恰心脏病发病机制中重要的信号通路。从这种寄生虫中鉴定并克隆了一个假定的血栓素合成酶基因，我们还计划检查类二十烷KOs并表征这些KOs的表型。类二十烷途径已经为治疗心血管疾病提供了靶点，我们目前的研究很可能为治疗这一重要的人类寄生虫病提供额外的靶点。花生四烯酸合成的类二十烷酸是心血管系统的重要介质。我们的研究表明，类二十烷酸是由恰加斯病的病原体克氏锥虫合成的，而恰加斯病与心血管异常有关。我们计划研究类二十烷酸及其受体在心脏病这一重要病因中的作用。

DESCRIPTION (provided by applicant): Eicosanoids are important mediators of the cardiovascular system in health and disease. Chagasic cardiomyopathy is one of the most important causes of cardiovascular diseases in many endemic areas of the world. Infection with the parasite T. cruzi causes this disease which has many characteristics similar to the effects of certain eicosanoids such as thromboxane. This infection leads to activation of the inflammatory cascade. It also causes vasoconstriction, platelet aggregation and smooth muscle cell proliferation. Our preliminary data indicate that discrete signaling pathways from host thromboxane prostanoid recptor (TP) regulate the host- parasite relationship. In endothelial cells (ECs) isolated from TP knockout (KO) and WT mice we found that expression of mutated TP in TP-KO ECs can be used as an approach to dissect the molecular regulation of intracellular parasite growth. We demonstrated that G-alpha q or G- alpha11 are responsible, in part, for the control of intracellular parasite growth. We will perform additional experiments to confirm that those pathways are directly responsible for the suppression of parasite growth by host TP and thus define the mechanism(s) through which second messenger's affects parasite growth. The endpoints to be examined include susceptibility of these cells to this parasite, adhesion and penetration, parasite growth and down-stream signaling pathways of G alpha -q. ECs obtained from various conventional and KO mice will be used to determine important pathways in the pathogenesis of this infection. Cells other than ECs have TP but in our studies we use murine cardiac ECs because they are readily obtained, easily transfectable and maintain their phenotype. Other cell types, such as murine cardiac myocytes, are difficult to obtain in pure form and do not maintain their phenotype in culture. Therefore, ECs act as a surrogate for all cells with TP and are a model for the characterization of the effects of TP signaling. Mice in which various parts of the eicosanoid pathway have been deleted will be used to evaluate signaling pathways important in the pathogenesis of chagasic heart disease. Having identified and cloned a putative thromboxane synthase gene from this parasite we also plan to examine eicosanoid KOs and characterize the phenotype of these KOs. The eicosanoid pathway has already provided targets for the treatment of cardiovascular disease and our current studies are likely to provide additional targets for the treatment of this important human parasitic disease. Eicosanoids which are synthesized from arachidonic acid are important mediators in the cardiovascular system. Our studies indicate that eicosanoids are synthesized by the parasite Trypanosoma cruzi, the causative agent of Chagas' disease which is associated with cardiovascular abnormalities. We plan to investigate the role of eicosanoids and their receptors in this important cause of heart disease.