Role of the X-chromosome in Pulmonary Arterial Hypertension

描述(申请人提供)：肺动脉高压(PAH)是一种严重的肺部疾病，其特征是小肺动脉的增殖性改变，导致血管狭窄，肺动脉压力升高和右心衰竭。越来越多的证据表明，PAH患者肺部的增生性病变类似于肿瘤，具有单克隆性扩张和遗传不稳定性。支持这一点，我们最近在PAH肺内皮细胞中发现了染色体异常，包括16%的女性病例中X染色体的马赛克缺失。我们还发现非常扭曲的X染色体失活模式的频率高得惊人(32%)，这可能代表不活跃的X染色体的单克隆性或重新激活。在这项研究中，我们将对原代培养的细胞和未培养的肺组织中的X-失活进行详细的分析，以区分这两种假说，并确定X-染色体缺失的病例是否失去了活性或非活性的X。X连锁基因的等位基因特异性表达将使用下一代测序和原位杂交来可视化X-染色体拷贝数和X-失活的标志XIST在未培养组织切片中的表达。确定单克隆性的频率对于PAH发病的瘤样模型至关重要，X染色体的其他异常可能部分解释了女性的发病率高于男性。 公共卫生相关性：肺动脉高压(PAH)是一种严重的、潜在威胁生命的肺部疾病，病因复杂。这项研究将使用接受肺移植的PAH患者的肺组织来描述在疾病过程中发生的X染色体的变化。长期目标是了解PAH是如何发展的，并设计更有效的治疗方法。(摘要结束)

DESCRIPTION (provided by applicant): Pulmonary arterial hypertension (PAH) is a serious lung disease characterized by proliferative changes in the small pulmonary arteries that leads to vessel narrowing, elevated pulmonary artery pressure and right heart failure. There is growing evidence that proliferative lesions in the lungs of PAH patients are akin to neoplasia, with monoclonal expansion and genetic instability. Supporting this, we recently identified chromosomal abnormalities in endothelial cells from PAH lungs, including mosaic deletions of the X-chromosome in 16% of female cases. We have also found a surprisingly high frequency (32%) of very skewed X-inactivation patterns, which may represent monoclonality or reactivation of the inactive X-chromosome. In this study we will conduct a detailed analysis of X-inactivation in primary cell cultures and uncultured lung tissue to distinguish these two hypotheses and also identify whether cases with X-chromosome deletion have lost the active or inactive X. Allele-specific expression of X- linked genes will be analyzed using next generation sequencing and in situ hybridization will be performed to visualize X-chromosome copy number and XIST expression, a marker of X-inactivation, in uncultured tissue sections. Determining the frequency of monoclonality is critical to the neoplasia-like model for PAH pathogenesis and other abnormalities of the X-chromosome may in part explain the higher incidence in females than males. PUBLIC HEALTH RELEVANCE: Pulmonary arterial hypertension (PAH) is a serious, potentially life-threatening lung disorder with a complex etiology. This study will use lung tissue from patients with PAH who have undergone lung transplantation to characterize changes in the X-chromosome that occur during the course of the disease. The long-term goal is to understand how PAH develops and design more effective treatments. (End of Abstract)