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

项目摘要/摘要 10%的人会发生尿路结石。泌尿系结石造成的经济负担超过2 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 我们提供了初步的证据，DNA测序与增强 培养方法可以用来鉴定许多尿路结石中的微生物群(尿路结石中的细菌)。 比单独通过标准培养获得更多的结石。然而，关键的知识差距存在于潜在的 尿路结石的病理生理学机制。令人担忧的是，尿路结石的患病率正在上升， 新的治疗方法也没有被开发出来。尽管含有草酸钙的尿液已经过饱和 与结石形成相关的是，非结石形成者常出现过饱和尿液。积累 有证据支持细菌在尿路结石病理生理学中的作用。首先，细菌聚集成草酸钙 (CaOx)，这是导致大多数尿路结石疾病的晶体类型。第二，初步的体外研究表明 细菌鞭毛是细菌促进晶体聚集的重要成分。第三，细菌 在活体小鼠模型中增加晶团的大小。我们的长期研究目标是开发新的 减少尿路结石复发的治疗策略。 我们假设鞭毛对结石的形成有直接贡献。开始确定…的功能作用 对于结石形成中的鞭毛，我们将测试缺乏关键鞭毛成分和/或功能的细菌突变株 体外和体内促进CaOx聚集的能力。(目标1)。除了鞭毛，我们还假设 其他遗传因素也可能对岩石形成起作用。我们将进行细菌突变筛选，以 识别与CaOx晶体相互作用有关的非鞭毛基因。此外，我们还将探讨 与尿路分离相比，与结石相关的细菌分离中富含已鉴定的基因 与石头有关(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).