A Microbial Model for the Formation of Calcium Oxalate and Calcium Phosphate Stones

项目概要/摘要 泌尿系统结石发生在10%的人。泌尿系结石的经济负担占2%以上 每年10亿美元。过去的研究表明，细菌可以从大约三分之一的 我们已经提供了初步的证据，DNA测序与增强的 培养方法可用于在许多情况下鉴定尿结石微生物群（尿结石中的细菌）。 更多的石头比标准培养单独。然而，在基本的知识方面存在重大的知识差距， 泌尿系结石的病理生理机制。令人担忧的是，尿结石的患病率正在增加， 新的治疗方法也没有被开发出来。虽然草酸钙过饱和的尿液已经被 与结石形成相关的是，非结石形成者中通常存在过饱和尿液。积累 证据支持细菌在泌尿系结石病理生理学中的作用。首先，细菌聚集成草酸钙 （CaOx），负责大多数泌尿系统结石疾病的晶体类型。第二，最初的体外研究表明， 细菌鞭毛是细菌促进晶体聚集的重要成分。第三，细菌 增加体内鼠模型中晶体簇的尺寸。我们的长期研究目标是开发新的 泌尿系统结石的治疗策略，减少泌尿系统结石复发。 我们推测鞭毛直接参与了成石作用。开始确定的职能作用 鞭毛在结石形成中的作用，我们将测试缺乏关键鞭毛成分和/或功能的细菌突变体， 在体外和体内促进CaOx聚集的能力。(Aim 1）。除了鞭毛，我们还假设 其他遗传因素也可能有助于成石作用。我们将进行细菌突变筛查， 鉴定参与与CaOx晶体相互作用的非鞭毛基因。此外，我们亦会探讨 相对于尿分离株， 与结石相关（目标2）。

Project Summary/Abstract Urinary stones occur in 10% of people. The economic burden from urinary stones accounts for more than 2 billion dollars annually. Past studies have demonstrated that bacteria can be cultured from about one-third of urinary stones and we have provided the initial demonstration that DNA sequencing coupled with enhanced culture methods can be used to identify the urinary stone microbiota (the bacteria in urinary stones) in many more stones than by standard culturing alone. Yet, critical knowledge gaps exist concerning the underlying mechanisms of urinary stone pathophysiology. Alarmingly, prevalence of urinary stones is increasing, and new treatments are not being developed. Although urine supersaturated with calcium oxalate has been associated with stone formation, supersaturated urine is often present in non-stone formers. Accumulating evidence supports a bacterial role in urinary stone pathophysiology. First, bacteria aggregate to calcium oxalate (CaOx), the type of crystal responsible for most urinary stone disease. Second, initial in vitro studies indicate that bacterial flagella are important components in bacterial promotion of crystal aggregation. Third, bacteria increase the size of crystal clusters in an in vivo murine model. Our long-term research goal is to develop new urinary stone treatment strategies that reduce urinary stone recurrence. We hypothesize that flagella directly contribute to lithogenesis. To begin to determine the functional role of flagella in stone formation, we will test bacterial mutants lacking key flagella components and/or function for their ability to promote CaOx aggregation in vitro and in vivo. (Aim 1). Besides flagella, we also hypothesize that other genetic factors may contribute to lithogenesis as well. We will perform a bacteria mutant screen to identify non-flagellar genes involved in interactions with CaOx crystals. In addition, we will explore whether the identified genes are enriched in bacterial isolates associated with stones relative to urinary isolates not associated with stones (Aim 2).