In vitro models of subgingival communities and their in vivo pathogenic potential

描述(申请人提供)：牙周炎是一种支持牙齿结构的炎症状态，由致病菌落与宿主相互作用所致。这种疾病的病理生理学机制尚不完全清楚，因此新的预防或治疗策略的发展仍然难以捉摸。微生物群落是微生物相互作用的复杂动态实体，因此表现出不同于单个物种的表型特征。此外，群落环境改变了微生物的致病潜能，这不仅是通过它们与宿主组织的直接相互作用实现的，也是通过调节整个群落的TE行为间接实现的。因此，了解牙周炎的病因学需要将微生物群落视为感染性挑战，而不是将重点放在单一物种作为病原体。目前尚无接近分类复杂性、环境条件和龈下环境中微生物生长速度的群落模型。这样的模型对于研究支持致病群落的物种间相互作用是必要的。此外，还需要牙周炎的动物模型，以便研究类人群落的致病潜力。在这项建议中，我们将使用最近获得的关于牙周炎患者微生物组组成的知识来开发一个20个物种的模型龈下群落。该模型将在与体内相似的营养和环境条件下进行连续培养。利用这个群落模型，我们将研究对于牙周炎相关物种的生存至关重要的物种间的相互作用。特别是，我们将测试一种名为“龈下核心物种”的群体的作用，这些物种是健康和疾病社区的重要组成部分，并通过支持牙周炎相关的分类群而潜在地充当社区新陈代谢锚。然后，我们将评估模型20个物种群落在小鼠口腔中的定植和致病性，测试作为一个群落生长并预先适应氧气等环境压力的微生物比单一物种更能定植和诱发牙周炎的假设。因此，这项建议的具体目的是：1)建立和表征一个代表牙周炎的基于恒化器的牙周下群落模型，并测试核心物种作为牙周炎相关社区成员生存的基础所起的作用；2)建立一个基于社区的口腔灌胃小鼠牙周炎模型。所提出的模型将在该领域产生重大影响，因为它们将使牙周炎发病机制的研究超越单一物种的研究，从而有助于识别调节致病群落建立的关键事件及其对宿主组织的影响。这一知识可能会指导新的策略的发展，以保存牙周健康。

DESCRIPTION (provided by applicant): Periodontitis is an inflammatory condition of the supporting tooth structures that results from the interaction of pathogenic subgingival communities with the host. The pathophysiology of this condition is not completely understood and thus the development of novel preventive or therapeutic strategies remains elusive. Microbial communities are complex dynamic entities in which microorganisms interact with each other, therefore displaying different phenotypic characteristics than individual species. Moreover, a community context modifies the pathogenic potential of microorganisms, which is realized not only by their direct interaction with host tissues but also indirectly by modulating te behavior of the whole community. Therefore, understanding the etiology of periodontitis requires considering microbial communities as the infectious challenge rather than focusing on single species as causative agents. Community models that approximate the taxonomic complexity, environmental conditions and growth rate of microorganisms in the subgingival environment are not available. Such models are necessary to investigate the inter-species interactions that support pathogenic communities. Moreover, animal models of periodontitis are required in which the pathogenic potential of human-like communities could be investigated. In this proposal, we will use recently acquired knowledge on the microbiome composition of humans with periodontitis to develop a 20-species model subgingival community. This model will be developed under continuous culture in nutritional and environmental conditions similar to those in vivo. Using this community model we will investigate inter-species interactions important for the survival of periodontitis-associated species. In particular, we will test the role of a group called "subgingival core species" which are important components of communities in health and disease and potentially serve as community metabolic anchors by supporting periodontitis-associated taxa. We will then evaluate the colonization and pathogenicity of the model 20-species community in the murine oral cavity, testing the hypothesis that microorganisms growing as a community and pre-adapted to environmental pressures such as oxygen are better able to colonize and induce periodontitis than single species. Accordingly, the specific aims of this proposal are: 1) To develop and characterize a chemostat-based subgingival community model representative of periodontitis and test the role of core species as fundamental for the survival of periodontitis- associated community members and 2) To develop a community-based oral gavage murine model of periodontitis. The models proposed will have great impact in the field as they will allow research on the pathogenesis of periodontitis to move beyond the study of single species, thereby facilitating identification of key events that modulate the establishmen of pathogenic communities and their effects on host tissues. This knowledge is likely to direct the development of new strategies for preservation of periodontal health.