Induction of Macrophage iNOS by Salmonella

描述(申请人提供)：肠道的各种血清型 革兰氏阴性细菌病原体沙门氏菌导致许多 对公众健康有影响的疾病，包括急性胃肠炎，如 还有伤寒。在感染过程中，这些微生物入侵 宿主的肠上皮细胞、树突状细胞和巨噬细胞。在……里面 通过这样做，细菌将特定的效应蛋白引入宿主细胞。 通过一种特殊的分泌装置。细胞骨架的变化和 这些蛋白诱导的细胞信号通路的激活有助于 细菌入侵也会引发宿主促炎因子的产生 分子。阐明效应蛋白是如何实现这些的 这些功能将有助于阐明该病的发病机制，并可能提出新的 沙门氏菌相关疾病的治疗方法。在预赛中 实验中，我发现效应器SopE2是一种鸟嘌呤核苷酸 哺乳动物Rho GTP酶的交换因子是沙门氏菌所必需的 依赖于诱导型一氧化氮合酶(INOS)的上调 负责控制人体内一氧化氮(NO)的产生 巨噬细胞。一氧化氮的促炎和免疫调节作用 抗微生物防御，以及与之相关的组织损伤 感染了。在进一步的研究中，我发现SopE2激活了 转录因子NF-kappa-B，既有其自身的，也有协同作用的 与TRAF6的相互作用，TRAF6是一种通过成员参与信号传递的适配器分子 属于Toll样受体和肿瘤坏死因子受体家族。建议进行的实验 在本申请中将扩展这些初步观察以阐明 SopE2及其同系物Sope的功能，通过(A)通过 SopE2和Sope启动的信号导致iNOS诱导，特别是 Rho GTP酶在这一过程中的作用(B)阐明SopE2和Sope如何 激活核因子-kappaB及其对TRAF依赖的影响 信号，(C)确定顺式作用转录调控元件在 对沙门氏菌感染和Sop诱导的信号有反应的iNOS启动子， 以及(D)研究SopE2和Sope在沙门氏菌诱导iNOS中的作用。 原代巨噬细胞和树突状细胞。这些研究的结果将会 阐明Sope和SopE2的新功能，并将提高对SopE和SopE2的理解 调控iNOS表达的机制。

DESCRIPTION (provided by applicant): Various serotypes of the enteric Gram-negative bacterial pathogen Salmonella are responsible for a number of diseases of public health significance, including acute gastroenteritis, as well as typhoid fever. During the course of infection, these organisms invade intestinal epithelial cells, dendritic cells and macrophages of the host. In doing so, the bacteria introduce specific effector proteins into the host cells through a specialized secretory apparatus. The cytoskeletal changes and activation of cellular signaling pathways induced by these proteins facilitate bacterial invasion and also elicit the production of host pro-inflammatory molecules. Elucidating exactly how the effector proteins carry out these functions would help to clarify the pathogenesis of, and might suggest new approaches to treating, Salmonella -associated disease. In preliminary experiments, I have found that the effector SopE2, a guanine nucleotide exchange factor for mammalian Rho GTPases, is necessary for the Salmonella -dependent upregulation of inducible nitric oxide synthase (iNOS), the enzyme that is responsible for controlling the production of nitric oxide (NO) in macrophages. The pro-inflammatory and immunomodulatory effects of NO contribute to anti-microbial defense, as well as to the tissue damage that is associated with infection. In further studies, I have found that SopE2 activates the transcription factor NF-kappa-B, both on its own, and in a synergistic interaction with TRAF6, an adaptor molecule involved in signaling via members of the Toll-like receptor, and TNF receptor families. The experiments proposed in this application will extend these preliminary observations to elucidate the function of SopE2, and its homolog SopE, by (a) examining the mechanism by which SopE2 and SopE initiate signals leading to iNOS induction, particularly the role of the Rho GTPases in this process (b) elucidating how SopE2 and SopE activate NF-kappa-B, and characterizing their influence on TRAF-dependent signals, (c) identifying cis-acting transcriptional regulatory elements in the iNOS promoter that respond to Salmonella infection, and to Sop-induced signals, and (d) examining the role of SopE2 and SopE in iNOS induction by Salmonella in primary macrophages and dendritic cells. The results of these studies will shed light on a novel function of SopE and SopE2 and will also improve understanding of the mechanisms that regulate iNOS expression.