Small molecule inhibitors of cariogenic biofilms

摘要 龋齿（蛀牙）是困扰美国公众的最普遍的传染病.生物膜 形成对于由致龋细菌诱导的龋齿的发展至关重要。变形链球菌 是一种适应生物膜生活方式的致龋细菌模型。生物膜内的细菌 对传统抗生素和宿主防御具有抗性;因此开发了新型抗生物膜试剂 干扰致龋细菌的生物膜形成和发展是必要的和关键的， 治疗和预防龋齿。具有抗生物膜作用的最有效和最通用的一类分子 这些特性是来自Melander小组发现的2-氨基咪唑（2-AI）支架的那些， 天然海产品。所述2-AI衍生物能够抑制和分散由以下物质形成的多种生物膜： 革兰氏阴性菌和革兰氏阳性菌。在上一个供资周期，我们取得了很大进展， 鉴定并表征了两种不同的2-AI衍生物，其抑制或分散S.致龋性变形菌 生物膜特别是。先导化合物不影响口腔链球菌的生物膜形成。我们 研究表明，一种2-AI衍生物选择性地靶向调节S.变形 生物膜、适合度和毒力。该化合物在体外抑制生物膜形成，在体内抑制细菌毒力。 复杂的微生物群落，表明它具有巨大的治疗潜力。我们发现的另一种衍生物 选择性地分散预先形成的S。在体外的变形杆菌生物膜，并抑制细菌定植和毒力 vivo.分散活性不是由任何已知的生物膜途径介导的，这表明了一种新的潜在的生物膜途径。 机制我们目前计划的目标是进一步探索这两类新的小分子， 定义它们的作用模式，并开发更有效的，选择性的化学探针来分解小分子- 定向基因调控和信号传导是生物膜发育的关键。提出了两个具体目标： 具体目的1：探讨选择性靶向致龋反应调节因子的分子机制 通过对2-AI衍生物和细菌的结构活性关系的研究， 发现计划，以启发设计和开发更有效和选择性的化学探针 以增强抗致龋活性。具体目标2：确定有效小分子的分子靶标， 分散致龋S.变形杆菌生物膜，并确定生物膜分散的潜在机制。一个 微生物学家、药物化学家、结构生物学家、动物模型专家 和牙医科学家将继续他们富有成效的合作， 先导化合物如何选择性地抑制和分散致龋生物膜并促进新的 防龋策略。这项申请将直接影响市民的口腔健康， 铅化合物在预防或治疗龋齿方面具有很大的治疗潜力。

Abstract Dental caries (tooth decay) is the most prevalent infectious disease afflicting American Public. Biofilm formation is crucial for the development of dental caries induced by cariogenic bacteria. Streptococcus mutans is a model cariogenic bacterium that has adapted to the biofilm lifestyle. Bacteria within a biofilm are extremely resistant to traditional antibiotics and host defense; therefore development of new classes of anti-biofilm reagents that interfere with the biofilm formation and development by cariogenic bacteria is necessary and critical for the treatment and prevention of dental caries. The most potent and versatile class of molecules with anti-biofilm properties are those derived from the 2-aminoimidazole (2-AI) scaffold discovered by the Melander group from natural marine products. The 2-AI derivative is capable of inhibiting and dispersing diverse biofilms formed by Gram-negative and Gram-positive bacteria. In the last funding cycle, we have made great progress, and identified and characterized two distinct 2-AI derivatives that either inhibit or disperse S. mutans cariogenic biofilms specifically. The lead compounds do not affect biofilm formation by commensal oral streptococci. Our studies have shown that one 2-AI derivative selectively targets a response regulator that modulates S. mutans biofilm, fitness and virulence. The compound inhibits biofilm formation in vitro and bacterial virulence in vivo in the complex microbial community, indicating it has great therapeutic potential. Another derivative we identified selectively disperses preformed S. mutans biofilms in vitro and inhibits bacterial colonization and virulence in vivo. The dispersion activity is not mediated by any known biofilm pathway, suggesting a novel underlying mechanism. The goal of our current proposal is to further explore these two new classes of small molecules, define their modes of action and develop more potent, selective chemical probes to dissect small molecules- directed gene regulation and signaling that are key to biofilm development. Two specific aims are proposed: Specific Aim 1: Explore molecular mechanisms of selective targeting of the response regulator of cariogenic bacteria by the 2-AI derivative and use both structure-activity relationship studies, and structure-based drug discovery schemes to enlighten the design and the development of more potent and selective chemical probes to enhance anti-cariogenic activity. Specific Aim 2: Identify molecular targets of the potent small molecule that disperses cariogenic S. mutans biofilms and determine the underlying mechanism of the biofilm dispersion. An interdisciplinary team among microbiologists, medicinal chemists, structural biologists, animal model experts, and dentist scientists will continue their productive collaborations, which should unravel molecular mechanisms how lead compounds selectively inhibit and disperse cariogenic biofilms and facilitate the development of new anti-caries strategies. The application will have a direct impact on the oral health of the general public since the lead compounds have great therapeutic potentials in preventing or treating dental caries.