Functional genomics of human variation to Salmonella invasion

描述（由申请人提供）：尽管公共卫生有所改善，疫苗取得了进步，许多类别的抗生素也得到了开发，但传染病仍占全球死亡人数的四分之一以上。然而，即使是最具破坏性的大流行病，历史也表明感染的严重程度和持续时间存在很大差异。候选人Dennis Ko博士的长期研究目标是确定细菌感染易感性差异的遗传基础。这一知识对于确定为什么某些个体对不同的感染具有抵抗力以及在开发降低易感个体的死亡率和发病率的疗法方面是重要的。 本提案中的实验将阐明人类遗传差异如何导致伤寒沙门氏菌感染的变异。第一个目标是确定人类遗传差异，修改入侵的S。伤寒杆菌培养细胞。这是通过一种新的遗传关联筛选来实现的，该筛选使用从数百个基因分型个体获得的细胞。然后通过测量RNA干扰对S的影响来验证筛选所揭示的遗传变异。伤寒侵袭。第二个目的是确定所鉴定的遗传变异如何影响S.伤寒侵袭。荧光显微镜和流式细胞术将用于确定细菌的摄取或细胞内生态位的早期建立是否受到影响。进一步的实验将包括干扰和评估已知在沙门氏菌入侵中发挥作用的分子，包括磷酸肌醇、Rho家族GTPases和分泌型细菌效应物。第三个目的是使用小鼠模型和临床关联数据评估已确定的疾病差异的相关性。将使用小鼠模型来确定所鉴定的基因是否影响感染的建立和/或在宿主内的传播。作为这些研究的补充，伤寒和其他疾病的遗传差异的相关性将通过病例对照遗传关联研究来解决。这些拟议实验的总体目标是发现基本的细胞生物学机制以及对健康和疾病重要的人类遗传变异。 高博士是Samuel米勒博士实验室的生命科学研究基金会研究员。他获得了斯坦福大学的医学博士学位。他对尼曼-匹克C型脂质储存障碍的论文研究为遗传学和细胞生物学奠定了坚实的基础，他将这些学科应用于他目前的研究，以了解人类对细菌感染的变异。作为一名博士后研究员，他的努力集中在开发一种新的筛选策略，用于发现改变沙门氏菌诱导的细胞死亡的遗传变异，并确定这些变异如何影响人类健康。高博士计划成立一个独立的研究实验室，研究对沙门氏菌的易感性。伤寒入侵，其目标是扩大他的重点，对宿主-病原体关系双方的变异和适应的重要性。

DESCRIPTION (provided by applicant): Despite improvements in public health, advancements in vaccines, and the development of many classes of antibiotics, infectious disease is still responsible for over a quarter of all deaths worldwide. However, even for the most devastating of pandemics, history demonstrates a large variability in the severity and duration of infection. The long-term research goal of the candidate, Dr. Dennis Ko, is to determine the genetic basis for differences in susceptibility to bacterial infections. This knowledge is important for determining why some individuals are resistant to different infections and in developing therapies to decrease the mortality and morbidity of susceptible individuals. Experiments in this proposal will elucidate how human genetic differences contribute to variation in infection by the bacteria that causes typhoid fever, Salmonella typhi. The first aim is to identify human genetic differences that modify invasion of S. typhi into cultured cells. This is accomplished through a novel genetic association screen using cells obtained from hundreds of genotyped individuals. Genetic variants revealed by the screen will then be validated by measuring the effect of RNA interference on S. typhi invasion. The second aim is to determine how the identified genetic variants affect the cellular mechanism of S. typhi invasion. Fluorescence microscopy and flow cytometry will be used to determine if uptake of the bacteria or early establishment of an intracellular niche is being affected. Further experiments will include perturbation and assessment of molecules known to play roles in Salmonella invasion, including phosphoinositides, Rho-family GTPases, and secreted bacterial effectors. The third aim is to assess the relevance of identified differences on disease using mouse models and clinical association data. Mouse models will be used to determine if the identified genes affect establishment of infection and/or spread within the host. As a complement to these studies, the relevance of the genetic differences upon typhoid fever and other diseases will be addressed through case-control genetic association studies. The overall goal of these proposed experiments is discovery of both basic cell biological mechanism as well as human genetic variation important for health and disease. Dr. Ko, is a Life Sciences Research Foundation fellow in the laboratory of Dr. Samuel Miller. He received MD-PhD degrees from Stanford University. His thesis research on the lipid-storage disorder Niemann-Pick Type C provided a firm foundation in genetics and cell biology, and he has applied these disciplines to his current research on understanding human variation to bacterial infection. As a postdoctoral fellow, his efforts focused on developing a novel screening strategy for discovering genetic variants that modify Salmonella- induced cell death and determining how these variants affect human health. Dr. Ko plans to start an independent research lab studying susceptibility to S. typhi invasion, with the goal of expanding his focus to the importance of variation and adaptation on both sides of the host-pathogen relationship.