Inhibition of oral bacterial biofilm formation using natural products-inspired or

描述（由申请人提供）：口腔细菌生物膜是蛀牙（龋齿）的主要原因，是感染和疾病的潜在渠道。这些生物膜已被证明含有数百种细菌，并且难以通过传统的口腔卫生习惯（如经常刷牙或用漱口水漱口）去除和根除。因此，需要新的预防和原位处理方法来解决这一问题。这项研究的中心假设是，小分子效应物可以通过抑制细菌信号传导和相关代谢途径来减少或消除口腔生物膜的形成。我实验室的初步研究表明，天然产物激发的有机化合物对减少模型生物膜形成细菌形成的生物膜有功效。这些化合物不影响细菌的生长和繁殖，但直接抑制生物膜的形成，浮游生长试验和基于微孔板的生物膜试验证明了这一点。我们假设这些化合物直接影响参与生物膜形成的细胞信号通路。例如，群体感应自诱导剂，如自诱导剂-2 (AI-2)，已被证明可以影响细胞行为和生物膜形成的范围广泛的远亲细菌。使用仿生方法，将合成结构相关的有机化合物库并筛选用于减少或抑制口腔生物膜形成细菌形成的生物膜。我们将重点关注AI-2作为构建我们文库的核心结构，因为该结构的衍生物可能对涉及生物膜形成的群体感应途径具有拮抗活性。这项初步研究将集中在三种生态学相关的生物：变形链球菌、血链球菌和naeslundii放线菌。变形链球菌与口腔疾病和龋齿的形成有关，而血链球菌和纳斯朗弓形虫是口腔拓荒者-定植的共生生物，参与了口腔生物膜的初步建立。此外，血链球菌和纳斯lundii与包括心内膜炎和放线菌病在内的重大人类疾病有关。因此，抑制这些生物形成生物膜可以防止致病生物的定植，如导致蛀牙和口腔疾病的变形链球菌或牙龈卟啉单胞菌。因此，所有这些生物对生物膜形成的抑制将直接影响口腔和全身健康。我们的方法是高度创新的，因为它专注于直接拮抗群体感应和生物膜形成途径与自诱导剂化合物的结构衍生物。我们认为，与筛选大量不相关的化合物相比，有针对性的设计和合成方法将更有效，并将使化合物的功效得到合理的提高。这项合作研究将由Nathaniel Cady教授领导，并利用与生物有机/合成化学家（Rabi Musah教授-奥尔巴尼大学）和生物膜/细菌信号专家Alexander Rickard教授（宾厄姆顿大学）的合作。我们期待这项工作取得几项重大成果。我们将确定口腔细菌生物膜形成的小分子抑制剂，并将评估其在环境相关模型流系统中的有效性。我们还将研究这些化合物对细胞间信号传导的影响，这将为未来的R21或R01提案奠定基础，以阐明其作用机制并通过合理的设计/合成系统地改善其活性。

DESCRIPTION (provided by applicant): Oral bacterial biofilms are major contributors to tooth decay (dental caries) and are a potential conduit for infection and disease. These biofilms have been shown to contain hundreds of species of bacteria and are resistant to removal and eradication by traditional oral hygiene practices, such as frequent tooth brushing or oral rinsing with mouthwash. Novel prophylactic and in situ treatment methods are therefore needed to address this problem. The central hypothesis of this effort is that small molecule effectors can reduce or eradicate oral biofilm-formation through inhibition of bacterial signaling and related metabolic pathways. Preliminary studies in my laboratory have shown that natural product-inspired organic compounds have efficacy in reducing biofilm formation by model biofilm forming bacteria. These compounds do not affect bacterial growth and propagation, but directly inhibit biofilm formation, as demonstrated by planktonic growth assays and microplate-based biofilm assays. We hypothesize that these compounds directly affect cell signaling pathways that are involved in biofilm formation. For instance, quorum sensing autoinducers, such as autoinducer-2 (AI-2) have been shown to affect cellular behavior and biofilm formation for a broad range of distantly related bacteria. Using a biomimetic approach, a library of structurally-related, organic compounds will be synthesized and screened for reduction or inhibition of biofilm formation by oral biofilm-forming bacteria. We will focus on AI-2 as the core structure for construction of our library, since derivatives of this structure could have antagonistic activity on quorum sensing pathways which have been implicated in biofilm formation. This initial study will focus on three ecologically relevant organisms: Streptococcus mutans, Streptococcus sanguinis and Actinomyces naeslundii. S. mutans has been implicated in oral disease and caries formation, while S. sanguinis and A. naeslundii are oral pioneer-colonizing commensal organisms that are involved in initial establishment of oral biofilms. Furthermore, S. sanguinis and A. naeslundii are associated with significant human diseases including endocarditis and actinomycosis. Therefore, inhibition of biofilm formation by these organisms could prevent later colonization by pathogenic organisms, such as S. mutans or Porphyromonas gingivalis that lead to tooth decay and oral disease. Inhibition of biofilm formation by all of these organisms would therefore directly affect both oral and systemic health. Our approach is highly innovative because it focuses on direct antagonism of quorum sensing and biofilm formation pathways with structural derivatives of autoinducer compounds. Rather than screening large libraries of unrelated compounds, we believe that a focused design and synthesis approach will be more effective and will enable rational improvement of compound efficacy. This collaborative research effort will be led by Prof. Nathaniel Cady, and leverages collaborations with a bioorganic/synthetic chemist (Prof. Rabi Musah - University at Albany) and an expert in biofilms/bacterial signaling, Prof. Alexander Rickard (Binghamton University). We expect several significant outcomes from this work. We will identify small molecular inhibitors of oral bacterial biofilm formation and will evaluate their effectiveness in environmentally relevant model flow-based systems. We will also investigate the effects of these compounds on intercellular signaling, which will serve as a foundation for a future R21 or R01 proposal to elucidate their mechanism of action and systematic improvement of their activity through rational design/synthesis. PUBLIC HEALTH RELEVANCE: The central hypothesis of this effort is that small molecule effectors can inhibit oral biofilm-formation through antagonism of bacterial signaling and metabolic pathways. Using a biomimetic, natural products-inspired approach, a library of structurally-related, organic compounds will be synthesized and screened for effectiveness in reducing or inhibiting biofilm formation by common orally-associated bacteria. Compounds having a strong inhibitory effect on biofilm formation will then be tested in supplemented saliva-fed flow cells to mimic environmental conditions in the oral cavity. Finally, we will explore our hypothesis that these compounds function through modulation of cell signaling behavior. The results of these studies will serve as the basis for a R21 or R01 application to elucidate their mechanism of action and develop them for therapeutic or prophylactic use.