Pathogenesis of PCD Lung Disease

描述（由申请人提供）：肺防御的一个重要组成部分是粘膜纤毛清除（MCC）的效率。原发性纤毛运动障碍（PCD）是人类纤毛功能异常和MCC缺陷的遗传模型。该项目的总体目标是将PCD的分子病因学与纤毛表型（超结构、纤毛搏动频率和模式）联系起来。我们假设纤毛超结构的某些异常（特别是外部和内部动力蛋白臂的缺陷）反映了基因突变，并且这些结构的编码是离散的基因群。此外，我们假设编码外动力蛋白臂与内动力蛋白臂蛋白的基因突变将对纤毛搏动频率和波形产生不同的影响。最后，我们假设我们将通过候选基因方法发现PCD中的致病突变，重点关注编码动力蛋白臂和中心复合体中的蛋白质的基因。为了验证我们的假设，我们收集了一个符合严格诊断标准的PCD患者队列（n=86）。在这些（以及另外60例）PCD患者中，我们将通过透射电子显微镜（TEM）和高速视频显微镜技术确定PCD纤毛的超结构和功能表型。测试PCD中致病基因突变的策略将使用几种不同的方法，包括通过使用基因内多态性来缩小候选基因的搜索范围的方法，以测试单个家庭中的“连锁”（排除图）。综上所述，这些研究将使我们能够确定纤毛超结构/功能与基因型之间的相关性。最终，我们将更好地了解由纤毛功能异常和纤毛黏液清除缺陷引起的气道疾病的发病机制。从更广泛的角度来看，在已知超微结构缺陷的患者中确定PCD的遗传基础，将为随后检测易患更常见气道疾病的纤毛功能障碍的“轻度”遗传形式提供机会。

DESCRIPTION (provided by applicant): An important component of lung defense is the efficiency of mucociliary clearance (MCC). Primary ciliary dyskinesia (PCD) is a human genetic model of abnormal ciliary function and defective MCC. The overall goals of this project are to relate the molecular etiology of PCD to the ciliary phenotype (ultra structure; ciliary beat frequency and pattern). We hypothesize that certain abnormalities in ciliary ultra structure (particularly defective outer and inner dynein arms) reflect genetic mutations, and that discrete groups of genes encode each of those structures. Moreover, we hypothesize that mutations in genes encoding for outer dynein arm versus inner dynein arm proteins will be associated with different effects on ciliary beat frequency and waveform. Finally, we hypothesize that we will discover disease-causing mutations in PCD by a candidate gene approach, focused on genes encoding proteins in the dynein arms and central complex. To test our hypotheses, we have accumulated a cohort (n=86) of PCD patients who fulfill rigorous diagnostic criteria. In these (and an additional 60) PCD patients, we will determine ciliary ultra structure by transmission electron microscopy (TEM) and functional phenotype of PCD cilia using high-speed video-microscopy techniques. The strategy to test for disease-causing genetic mutations in PCD will use several different approaches, including an approach to narrow the search for candidate genes by using intra-genic polymorphisms, to test for "linkage" (exclusion mapping) within individual families. Taken together, these studies will allow us to determine correlations between ciliary ultra structure/function and genotype. Ultimately, we will develop a better understanding of the pathogenesis of airway disease resulting from abnormal ciliary function and defective mucociliary clearance. From a broader perspective, the identification of the genetic basis of PCD in patients with known ultrastructural defects will later provide the opportunity to test for "milder" genetic forms of ciliary dysfunction that predispose to more common airways diseases.