Identifying disease mechanisms of a periodontal pathogen

 描述（由申请人提供）：牙周炎是一种口腔炎性疾病，可导致骨质破坏和牙齿脱落[1]。它是世界上最流行的疾病之一，影响了几乎一半的美国成年人（6470万人）[2]。 多种微生物与该疾病相关，包括几种革兰氏阴性机会致病菌[3，4]。人们认为，病原体之间的种间相互作用[5]以及病原体与口腔植物群之间的相互作用[6]会加剧疾病表型。这种相互作用网络的复杂性阻碍了我们对牙周病的理解，利用模型多微生物群落[6，7]和口腔感染动物模型[5，8]的努力极大地有益于该领域。此前我们 证明革兰氏阴性条件致病菌伴放线菌聚集杆菌（Aa）和革兰氏阳性嗜热链球菌（Sg）之间的协同毒力是由代谢物交叉喂养[9]和微生物“飞行”反应介导的，所述反应导致感染期间Aa与Sg的最佳间隔[10]。这种“飞行”反应是由Aa生物膜溶解酶分散素B（Dsp B）协调的，我们发现Dsp B受铁敏感调节剂Fur的调节。因此，本提案的第一个目标是探索这种调节作为Aa避免铁限制（主要宿主免疫因素）的策略的潜在作用。该提案的第二个目标是应用下一代测序技术[11]来定义两种感染环境中的Aa转录组和全基因组适应性决定因素：（a）在鼠脓肿中与Sg共感染期间和（B）在恒河猴口腔感染期间。我们的主要假设是Aa对牙周植物群和宿主的提示都有反应，从而建立牙周感染。这些研究的结果将是高度全面的、公开可用的数据集，这些数据集将阐明牙周病原体Aa的新疾病机制。此外，几十年来，口腔微生物中已经描述了共聚集[12]，这表明这些微生物主动调节其物理排列作为健身益处，我们的研究将描述非运动性口腔细菌可以控制体内空间取向的潜在机制。

 DESCRIPTION (provided by applicant): Periodontitis is an inflammatory disease of the oral cavity that can lead to bone destruction and tooth loss [1]. It is one of the most prevalent diseases in the world, affecting almost half of all American adults (64.7 million individuals) [2]. Multiple microbes have been associated with this disease, including several Gram-negative opportunistic pathogens [3,4]. It is thought that disease phenotypes are exacerbated by interspecies interactions between pathogens [5] as well as between pathogens and the commensal oral flora [6]. The complexity of this interaction network has hindered our understanding of periodontal disease, and efforts utilizing model polymicrobial communities [6,7] and animal models for oral cavity infection [5,8] have greatly benefitted the field. Previously, we demonstrated that synergistic virulence between the Gram-negative opportunistic pathogen Aggregatibacter actinomycetemcomitans (Aa) and the Gram-positive commensal Streptococcus gordonii (Sg) is mediated by metabolite cross-feeding [9] and by a microbial "flight" response that results in optimal spacing of Aa from Sg during infection [10]. This "flight" response is orchestrated by the Aa biofilm-dissolving enzyme Dispersin B (DspB), and we found that DspB is regulated by the iron-sensing regulator Fur. Therefore, the first goal of this proposal is to explore the potential role of this regulation as a strategy by Aa to avoid iron restriction, a majo host immunity factor. The second objective of this proposal is to apply next-generation sequencing technologies [11] to define the Aa transcriptome and genome-wide fitness determinants in two infection environments: (a) during co-infection with Sg in a murine abscess and (b) during infection of the rhesus macaque oral cavity. Our principal hypothesis is that Aa responds to cues from both the commensal flora and the host to establish periodontal infections. The output of these studies will be highly comprehensive, publicly available data sets that will elucidate novel disease mechanisms by the periodontal pathogen Aa. Furthermore, coaggregation has been described among oral microbes for decades [12], suggesting that these microbes actively modulate their physical arrangement as a fitness benefit, and our studies will describe potential mechanisms by which non-motile oral bacteria can control spatial orientation in vivo.