HEMOGLOBIN-INDUCED VIRULENCE IN STREPTOCOCCUSPNEUMONIAE

1项目概要 2 3肺炎链球菌（Spn）定植于大多数儿童的上呼吸道形成生物膜。由于 4到机制仍不清楚，鼻咽携带导致侵袭性肺炎球菌病（IPD） 5，每年在全世界造成100多万人死亡。IPD的特点是殖民化的 6个肺，随后移位到胸膜腔和血流，引起致命的菌血症。一旦 7在循环中，Spn移位到脑膜引起脑膜炎或侵入心肌细胞形成 8种细胞内生物膜导致心脏损伤。虽然接种肺炎球菌疫苗减少了 9疾病负担，疫苗仅针对一部分菌株，对肺炎球菌几乎没有影响 10例菌血症和脑膜炎。在过去几年中，该提案的PI所做的努力导致了 11突破性的发现，血红蛋白（Hb），一种在运输过程中可以接触到Spn的分子， 12上呼吸道和肺和心脏的定殖，触发稳健的生物膜和易位的形成 13的肺炎球菌通过人类肺细胞。这些观察结果有力地支持了一个新的科学前提， 14 Hb信号传导是Spn定殖和疾病过程的关键。我们的首要目标是找出 血红蛋白（Hb）触发Spn毒力，导致肺炎球菌疾病的病理生理学 16并开始描述Spn中Hb信号传导的机制。具体目标1将使用反向遗传 17.鉴定Hb所需的蛋白质以抑制导致生物膜形成的信号， 18和肺细胞和心肌细胞的侵袭。无论该信号是沿着作用还是与之分离， 还将研究增加的细胞内铁库。具体目标2将实现一个不可知论者 20策略（Tn-seq）以确定额外的表面蛋白和Hb信号传导所必需的调节剂， 21使用肺炎球菌定植的鼠模型在体内测试Hb信号传导缺陷的关键候选物， 22疾病在完成后，这项工作将确定新的蛋白质的关键的病理生理学的IPD，新的抗原 23肺炎球菌疫苗，和新的目标抑制剂干扰建立和 24、IPD的发展 25 26 27 28 29 30

1 Project summary 2 3 Streptococcus pneumoniae (Spn) colonizes the human upper airways of most children forming biofilms. Due 4 to mechanisms still not understood, nasopharyngeal carriage leads to invasive pneumococcal disease (IPD) 5 that kills more than one million individuals every year worldwide. IPD is characterized by colonization of the 6 lungs with subsequent translocation to the pleural cavity, and bloodstream, to cause lethal bacteremia. Once 7 in circulation, Spn translocates to the meninges causing meningitis or invades cardiomyocytes forming 8 intracellular biofilms that lead to cardiac damage. Although pneumococcal vaccination has reduced the 9 burden of disease, vaccines only target a subset of strains and have little to no impact against pneumococcal 10 bacteremia and meningitis. Efforts made in the last few years by this proposal's PIs have resulted in the 11 groundbreaking discovery that hemoglobin (Hb), a molecule that is accessible to Spn during carriage in the 12 upper airways and colonization of lung and heart, triggers the formation of robust biofilms and translocation 13 of pneumococci through human lung cells. These observations strongly support a new scientific premise that 14 Hb signaling is key to Spn colonization and disease processes. Our overarching goal is to identify the proteins 15 by which hemoglobin (Hb) triggers Spn virulence leading to the pathophysiology of pneumococcal disease 16 and to begin to describe the mechanism of Hb signaling in Spn. Specific Aim 1 will use a reverse genetic 17 approach to identify the proteins required for Hb to transduce a signal leading to the formation of biofilms, 18 and invasion of lung cells and cardiomyocytes. Whether this signal acts along with, or it is separated from, an 19 increased pool of intracellular iron will also be investigated. Specific Aim 2 will implement an agnostic 20 strategy (Tn-seq) to determine additional surface proteins and the regulators necessary for Hb signaling and 21 test key candidates defective in Hb signaling in vivo using murine models for pneumococcal colonization and 22 disease. At completion, this work will identify new proteins key for the pathophysiology of IPD, new antigens 23 for pneumococcal vaccines, and new targets for inhibitors that interfere with the establishment and 24 progression of IPD. 25 26 27 28 29 30