Pulmonary Fibrosis and Telomerase Dysfunction

 描述（由申请人提供）：肺纤维化是一组异质性肺部疾病的特征，具有肺结构的不可逆破坏和气体交换的中断。这些疾病的原型，特发性肺纤维化（IPF），从诊断到死亡的中位预期寿命很短。编码端粒酶的蛋白质组分（TERT）或RNA组分（TERC）的基因中的突变导致家族性肺纤维化激酶亚组中的疾病，端粒酶是一种催化将六聚体核苷酸重复序列添加到线性染色体末端的核糖核蛋白酶。同样数量的家族有端粒酶功能障碍的证据，外周血端粒长度很短，但端粒酶基因没有编码突变。我们的假设是，端粒长度短，由基因突变而不是TERT或TERC引起，代表了IPF的一个重要机制。在这项拨款申请中，我们将传统的临床表型和连锁方法与下一代外显子组测序相结合，为IPF遗传学提供新的见解。首先，我们将描述与罕见的肺纤维化和短端粒长度的常染色体显性共分离的激酶中的非常短的端粒长度相关的临床表型。由于极端表型是基因发现的有力工具，我们将使用组织端粒酶表达、肺转录组特征和循环生物标志物的临床评价和分析来表征短端粒IPF表型。其次，我们将使用下一代外显子组测序来鉴定在已知家族性肺纤维化基因中没有突变的激酶发现队列中的罕见候选变体。将通过四种独立的方法对数据集进行过滤和优先排序：（1）通过与肺纤维化和/或短端粒长度的表型共分离的基因组区域，（2）通过等位基因频率，（3）通过预测的对蛋白质功能的有害影响和（4）基于B基因的频率及其在端粒和纤维化途径中的生物学作用。最终的目标是通过共分离，通过关联研究和蛋白质变体功能的研究来验证候选变体。这些研究有可能通过确定端粒缩短如何导致肺纤维化来开辟新的领域。我们多管齐下的方法为治疗干预提供了新的靶点，并将导致更好地了解由于端粒酶功能障碍导致的进行性肺纤维化的发病机制。

 DESCRIPTION (provided by applicant): Pulmonary fibrosis characterizes a heterogeneous group of lung disorders with irreversible destruction of lung architecture and disruption of gas exchange. The prototype of these diseases, idiopathic pulmonary fibrosis (IPF), has a short median life expectancy from diagnosis to death. Mutations in the genes encoding the protein component (TERT) or RNA component (TERC) of telomerase, a ribonucleoprotein enzyme that catalyzes the addition of hexameric nucleotide repeats to the ends of linear chromosomes, cause disease in a subset of kindreds with familial pulmonary fibrosis. An equal number of families has evidence of telomerase dysfunction, with very short peripheral blood telomere lengths, but no coding mutations in the telomerase genes. Our hypothesis is that short telomere lengths, caused by mutations in genes other than TERT or TERC, represent an important mechanism underlying IPF. In this grant application we merge traditional clinical phenotyping and linkage methods with next generation exome sequencing to provide new insights into IPF genetics. First, we will characterize the clinical phenotype associated with very short telomere lengths in rare kindreds that demonstrate autosomal dominant co-segregation of pulmonary fibrosis and short telomere lengths. Since extreme phenotypes represent a powerful tool for gene discovery, we will use clinical evaluations and analyses of tissue telomerase expression, lung transcriptome signatures and circulating biomarkers to characterize the short telomere IPF phenotype. Second, we will use next generation exome sequencing to identify rare candidate variants in the discovery cohort of kindreds without mutations in known familial pulmonary fibrosis genes. The datasets will be filtered and prioritized by four independent methods: (1) by genomic regions co- segregating with the phenotypes of lung fibrosis and/or short telomere length, (2) by allele frequency, (3) by predicted deleterious effects on protein function and (4) b gene-based frequencies and their biological roles in telomere and fibrosis pathways. The final aim will validate candidate variants by co-segregation in the kindreds they were discovered, by association studies and by investigations of protein variant function. These studies have the potential to break new grounds by determining how telomere shortening leads to lung fibrosis. Our multi-pronged approach offers the promise of new targets for therapeutic intervention and will lead to better understanding of the pathogenesis of progressive lung fibrosis due to telomerase dysfunction.