Oral Infectious Disease: Virulence and Host Determinants

描述：变形链球菌是正常口腔植物群的一部分，并在机会性条件下促进龋齿。了解宿主与沙门氏菌相互作用的因素。导致龋齿的变异体仍然是原始的。具体目标1：确定特定唾液分泌成分在龋齿发展中的影响。我们将研究三种唾液成分，高分子量唾液粘蛋白（Muc 19），低分子量唾液粘蛋白（Muc 10）和唾液淀粉酶（Amy 1）。所有这三个基因都已在小鼠基因组中被鉴定出来。我们将生产基因敲除小鼠用于龋齿实验的直接评估。我们还将生产双重和三重基因敲除动物，以测试对龋齿的累加、协同甚至竞争效应。 具体目标2：评估S。变异基因作为与口腔感染和随后的龋齿发展相关的毒力因子的作用。我们将重点关注：i）葡糖基转移酶B/C（gtf B/C）和gtf B/C/D; 2）抗原I/II（Ag I/II）;和3）在pH 5上调的推定的纤连蛋白/纤维蛋白原结合蛋白基因（fbp，Smu. 1449）。Ag I/II和fbp将作为单突变进行研究，并在遗传背景中，gtfB/C和gtfB/C/D，以帮助阐明它们在感染过程中的作用。将测定与用全唾液、腮腺唾液、下颌下/舌下唾液、Muc 19、Muc 10或淀粉酶包被的羟基磷灰石珠的结合曲线。将测试感染性突变菌株的龋齿诱导。我们还将进行突变体与野生型菌株的cDNA微阵列分析，以确定Fbp是否在上调或下调细胞壁相关蛋白的功能。我们将确定唾液对S.变形杆菌以及在缺乏特定基因、gtfs、fbp和AgI/II的情况下细胞如何反应。具体目标3：确定S.变形菌毒力因子和一种特殊的唾液分泌成分在龋病的发展。随着我们阐明唾液成分和S。在龋齿中的变异基因，我们将确定宿主和细菌决定之间的对比或添加剂/合作的相互作用。 这些研究将描述在龋齿中起作用的特定细菌和宿主决定因素。未来的研究可以集中在宿主-病原体相互作用的分子机制。结果可以指示治疗龋齿高风险患者的重要治疗靶点（即，口腔干燥症患者）。

DESCRIPTION: Streptococcus mutans is part of the normal oral flora, and promotes caries under opportunistic conditions. Knowledge of interacting factors between host and S. mutans that contribute to caries is still primitive. Specific Aim 1: Ascertain the influence of specific salivary secretory constituents in the development of caries. We will study three salivary constituents, high molecular weight salivary mucin (Muc19), low molecular weight salivary mucin (Muc10), and salivary amylase (Amy 1). All three genes have been identified in the mouse genome. We will produce knockout mice for direct evaluation in caries experiments. We will also produce double and triple knockout animals to test for additive, synergistic, or possibly even competitive effects on caries. Specific Aim 2: Evaluate S. mutans genes for their role as virulence factors associated with infection of the oral cavity and subsequent caries development. We will focus on: i) glucosyltransferase B/C (gtfB/C) and gtfB/C/D; 2) Antigen I/II (Ag I/II); and 3) a putative fibronectin/fibrinogen-binding protein gene that is up-regulated at pH 5 (fbp, Smu. 1449). Ag I/II and fbp will be studied as single mutations, and in the genetic backgrounds, gtfB/C and gtfB/C/D, to help elucidate their roles in the infection process. Binding profiles to hydroxyapatite beads, coated with whole saliva, parotid saliva, submandibular/sublingual saliva, Muc l9, Muc 10 or amylase will be determined. Infectious mutant strains will be tested for induction of caries. We will also perform cDNA microarray analyses of mutant versus wild-type strains to determine whether Fbp functions in the up- or down-regulation of cell-wall associated proteins. We will determine the effects of saliva on gene expression in S. mutans and how the cells respond in the absence of specific genes, gtfs, fbp and AgI/II. Specific Aim 3: Determine the interaction between an S. mutans virulence factor and a specific salivary secretory constituent in the development of caries. As we elucidate the roles of salivary constituents and S. mutans genes in caries, we will then determine contrasting or additive/cooperative interactions between host and bacterial determinates. These studies will delineate specific bacterial and host determinants that function in caries. Future studies can then focus on molecular mechanisms of host-pathogen interactions. Results may indicate important therapeutic targets to treat patients at high risk for caries (i.e., patients with xerostomia).