Analysis Of Group A Streptococcus-Saliva Interaction

描述（由申请人提供）：本研究旨在研究A群链球菌（GAS）与唾液的相互作用。提出的研究的关键目标是启动GAS发病机制的一个关键领域的分子研究。重要的是，尽管60年来我们都知道唾液是咽炎患者传播GAS的主要媒介，但GAS-唾液的相互作用一直是很少研究的主题。此外，由于唾液包裹在后咽，在咽感染过程中，唾液和GAS之间存在持续的相互作用。了解GAS对唾液的反应将增强我们对GAS如何感染人类口咽部并从咽炎患者传播的理解。目的1：测定GAS基因在人唾液中的表达。为此，我们将使用Affymetrix定制设计的表达微阵列来分析人类唾液生长过程中的GAS转录组。我们将通过进一步研究在唾液生长过程中高表达或在唾液生长过程中与标准实验室培养基生长过程中上调的GAS基因来优化表达微阵列分析的使用。我们将重点研究编码细胞外蛋白的基因，因为这些基因最有可能参与宿主-病原体的相互作用。目的2：确定体外GAS-唾液相互作用过程中高表达或上调的靶向GAS细胞外蛋白编码基因是否在咽炎患者体内表达相似。目的3：确定在人唾液生长过程中是否产生特异性的GAS细胞外蛋白。目的4：确定通过成功完成Specific Aims 1-3鉴定的特定GAS细胞外蛋白编码基因的失活是否会导致人唾液生长的改变。由于GAS-唾液相互作用的研究很少，在拟议的研究中检查的许多基因可能是40%的GAS基因组编码未知功能蛋白质的一部分。本项目旨在促进对人类口咽部GAS发病机制的基本理解，这可能会刺激研究这种常见病原体的治疗或预防措施的新途径。仅在美国，气体性咽炎每年的成本估计为150亿美元，并且作为风湿热的诱因，气体性咽炎仍然是世界范围内可预防的儿科心脏病的主要原因。

DESCRIPTION (provided by applicant): This study is designed to examine the interaction of group A Streptococcus (GAS) with saliva. The key goal of the proposed research is to initiate the molecular investigation of a crucial area of GAS pathogenesis. Importantly, GAS-saliva interaction has been the subject of little inquiry despite knowing for 60 years that saliva is a major vector for the transmission of GAS from patients who have pharyngitis. Also, given that saliva coats the posterior pharynx, there is constant interplay between saliva and GAS during pharyngeal infection. Knowledge of how GAS responds to saliva will augment our understanding of how GAS infects the human oropharynx and spreads from patients with pharyngitis. Aim 1: To asses GAS global gene expression when cultivated in human saliva. For this aim, we will use Affymetrix custom-designed expression microarrays to analyze the GAS transcriptome during growth in human saliva. We will optimize use of the expression microarray analysis by futher investigation of GAS genes that are highly expressed during growth in saliva or that are upregulated during growth in saliva compared to growth in standard laboratory media. We will focus our inquiry on genes encoding extracellular proteins, as these are most likely to participate in host-pathogen interaction. Aim 2: To determine whether targeted GAS extracellular protein-encoding genes highly expressed or upregulated during in vitro GAS-saliva interaction are expressed similarly in vivo in humans with pharyngitis. Aim 3: To establish whether specific GAS extracellular proteins are produced during growth in human saliva. Aim 4: To determine whether inactivation of particular GAS extracellular protein-encoding genes identified by successful completion of Specific Aims 1-3 results in altered growth in human saliva. As GAS-saliva interaction has been minimally investigated, many of the genes examined in the proposed research are likely to be part of the 40% of the GAS genome encoding proteins of unknown function. This project seeks to contribute to fundamental understanding of GAS pathogenesis in the human oropharynx which may stimulate new avenues of investigation for therapeutic or preventive measures for this common pathogen. GAS pharyngitis costs an estimated $15 billion/year in the US alone, and as the instigator of rheumatic fever, GAS remains, worldwide, the leading cause of preventable pediatric heart disease.