P. aeruginosa type III secreted effectors in corneal disease

铜绿假单胞菌感染是与长期配戴相关的角膜疾病的常见原因 隐形透镜在美国使用。铜绿假单胞菌用于促进疾病的主要毒力因子之一是 它的III型分泌系统，一个允许细菌直接注射效应蛋白的分子注射器， 进入目标宿主细胞。III型分泌物在角膜疾病中的作用尚未得到广泛研究，但 最初的报道表明，角膜疾病依赖于角膜上皮细胞表达的效应子的补体， 感染细菌表达强效磷脂酶ExoU的“细胞毒性”菌株广泛依赖于III型 分泌促进疾病，而产生ExoS的“侵入性”菌株，似乎不依赖于III型 分泌物以引起角膜疾病。 我们重新审视了III型分泌物在ExoS+引起的角膜疾病发病机制中的作用， 铜绿假单胞菌的“侵入性”分离株。我们的初步数据表明，角膜疾病严重依赖于 III型分泌和两个效应ExoS和ExoT，特别是。此外，我们提供的证据表明， III型分泌物在角膜疾病中的主要作用是避免浸润中性粒细胞的杀伤。 因此，本提案的重点是确定ExoS的单个酶活性的作用 和ExoT在体内防止中性粒细胞清除中的作用。我们将把这些发现与实验联系起来 目的是检查ExoS和ExoT在防止分离的原代嗜中性粒细胞的吞噬杀伤中的作用。 我们还将研究表达ExoU的“细胞毒性”和表达ExoS的“细胞毒性”之间的发病机制的差异。 表达铜绿假单胞菌的“侵入性”菌株，以确定是否有任何差异可以直接与 这两个效应器的活动。 了解效应蛋白在角膜疾病中的作用是制定角膜疾病治疗方案的重要一步。 预防和治疗眼部铜绿假单胞菌感染的新策略。

P. aeruginosa infections are a common cause of corneal disease associated with extended-wear contact lens use here in the US. One of the primary virulence factors P. aeruginosa uses to promote disease is its type III secretion system, a molecular syringe that allows the bacterium to directly inject effector proteins into targeted host cells. The role of type III secretion in corneal disease has not been studied extensively, but initial reports suggest that corneal disease depends on the complement of effectors being expressed by the infecting bacteria. "Cytotoxic" strains expressing the potent phospholipase ExoU rely extensively on type III secretion to promote disease, whereas ExoS-producing "invasive" strains, appear to not rely on type III secretion in order to elicit corneal disease. We have revisited the role of type III secretion in the pathogenesis of corneal disease elicited by ExoS+ "invasive" isolates of P. aeruginosa. Our preliminary data demonstrates that corneal disease relies critically on type III secretion and on the two effectors ExoS and ExoT, in particular. In addition, we provide evidence that the primary role of type III secretion in corneal disease is to stave off killing by infiltrating neutrophils. Accordingly, the focus of this proposal is to determine the role of the individual enzymatic activities of ExoS and ExoT in preventing clearance by neutrophils in vivo. We will correlate these findings with experiments aimed at examining the role of ExoS and ExoT in preventing phagocytic killing by isolated primary neutrophils. We will also examine the difference in pathogenesis between ExoU-expressing "cytotoxic" and ExoS- expressing "invasive" strains of P. aeruginosa in order to determine if any differences can be directly linked to the activities of these two effectors. Understanding the role of effector proteins in corneal disease is an important step towards formulating new strategies for preventing and treating P. aeruginosa infections of the eye.