Small molecule inhibitors of cariogenic biofilms

摘要 龋齿(龋齿)是困扰美国公众的最普遍的传染病。生物膜 致龋菌的形成对龋病的发生发展起着至关重要的作用。变形链球菌 是一种已适应生物膜生活方式的模式致龋菌。生物膜内的细菌非常 对传统抗生素的耐药性和宿主防御；因此开发新型抗生物被膜试剂 干扰致龋菌生物膜的形成和发育是必要的和关键的 龋齿的治疗和预防。最有效、用途最广的具有抗生物被膜功能的分子 性能是由Melander小组发现的来自2-氨基咪唑(2-AI)支架的那些 天然海产品。该2-AI衍生物能够抑制和分散由以下物质形成的各种生物膜 革兰氏阴性和革兰氏阳性细菌。在上一个筹资周期中，我们取得了很大进展， 鉴定和鉴定了两种不同的2-AI衍生物，它们抑制或分散变形链球菌的致龋性 特别是生物膜。先导化合物不影响共生口腔链球菌生物膜的形成。我们的 研究表明，一种2-AI衍生物选择性地针对调节变形链球菌的反应调节因子 生物膜、适合性和毒性。该化合物体外抑制生物被膜形成，体内抑制细菌毒力。 复杂的微生物群落，表明其具有很大的治疗潜力。我们确认的另一种衍生品 选择性地分散体外形成的变形链球菌生物膜，并抑制细菌在体内的定植和毒力 活着。分散活性不是由任何已知的生物膜途径介导的，提示了一种新的潜在的 机制。我们目前提议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，开发更有效、更具选择性的化学探针来解剖小分子- 定向的基因调控和信号传递是生物膜发育的关键。提出了两个具体目标： 特异靶向1：探讨致龋性反应调节因子选择性靶向的分子机制 细菌通过2-AI衍生物和使用构效关系研究，并以结构为基础的药物 启发设计和开发更有效和更有选择性的化学探针的发现计划 增强抗龋齿活性。具体目标2：确定有效小分子的分子靶标 分散致龋性变形链球菌生物膜，并确定生物膜分散的潜在机制。一个 由微生物学家、药物化学家、结构生物学家、动物模型专家、 牙医科学家将继续他们富有成效的合作，这将揭开分子机制的面纱 先导化合物如何选择性地抑制和分散致龋性生物膜并促进新的 防龋策略。这项申请会对市民的口腔健康有直接影响，因为 先导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.