Oral Infectious Disease: Virulence and Host Determinants

口腔传染病：毒力和宿主决定因素

• 批准号: 6858280
• 负责人: DAVID JOHN CULP
• 金额: $ 10.63万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2006-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6858280
• 关键词: Streptococcus mutans; amylases; bacteria infection mechanism; bacterial antigens; bacterial genetics; biotechnology; dental caries; disease /disorder model; enzyme activity; fibrinogen; fibronectins; gene expression; genetically modified animals; hexosyltransferase; host organism interaction; hydroxyapatites; laboratory mouse; microarray technology; mucins; oral bacteria; protein binding; protein structure function; saliva; virulence

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).

描述：变形链球菌是正常口腔菌群的一部分，在机会条件下会促进龋齿。对于宿主和变形链球菌之间导致龋齿的相互作用因素的了解仍然很原始。具体目标 1：确定特定唾液分泌成分对龋齿形成的影响。我们将研究三种唾液成分：高分子量唾液粘蛋白​​ (Muc19)、低分子量唾液粘蛋白​​ (Muc10) 和唾液淀粉酶 (Amy 1)。所有这三个基因均已在小鼠基因组中得到鉴定。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来测试对龋齿的加性、协同甚至可能的竞争效应。 具体目标 2：评估变形链球菌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) 葡萄糖基转移酶 B/C (gtfB/C) 和 gtfB/C/D； 2) 抗原I/II(Ag I/II)； 3) 假定的纤连蛋白/纤维蛋白原结合蛋白基因，在 pH 5 时上调（fbp，Smu.1449）。 Ag I/II 和 fbp 将作为单一突变进行研究，并在遗传背景 gtfB/C 和 gtfB/C/D 中进行研究，以帮助阐明它们在感染过程中的作用。将测定与涂有全唾液、腮腺唾液、下颌下/舌下唾液、Muc 19、Muc 10或淀粉酶的羟基磷灰石珠的结合特征。将测试感染性突变株是否诱发龋齿。我们还将对突变株与野生型菌株进行 cDNA 微阵列分析，以确定 Fbp 是否在细胞壁相关蛋白的上调或下调中发挥作用。我们将确定唾液对变形链球菌基因表达的影响，以及细胞在缺乏特定基因、gtfs、fbp 和 AgI/II 的情况下如何反应。具体目标 3：确定变形链球菌毒力因子和特定唾液分泌成分在龋齿发展过程中的相互作用。当我们阐明唾液成分和变形链球菌基因在龋齿中的作用时，我们将确定宿主和细菌决定因素之间的对比或相加/协同相互作用。 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于宿主与病原体相互作用的分子机制。结果可能表明治疗龋齿高风险患者（即口干症患者）的重要治疗靶点。