Role of the X-chromosome in Pulmonary Arterial Hypertension

项目摘要 肺动脉高压是一种以增生性改变为特征的严重肺部疾病 导致血管狭窄、肺动脉压升高， 右心衰竭越来越多的证据表明，PAH患者肺部的增生性病变 类似于瘤形成，具有单克隆扩增和遗传不稳定性。为此，我们最近 在PAH肺的内皮细胞中发现了染色体异常，包括 16%的女性病例中有X染色体。我们还发现了令人惊讶的高频率（32%） 非常偏斜的X-失活模式，这可能代表单克隆性或重新激活的 不活跃的X染色体在这项研究中，我们将进行详细的分析，X-失活的原发性 细胞培养和未培养的肺组织来区分这两种假设，并确定是否 例X染色体缺失者失去了活性或非活性X染色体。等位基因特异性表达X- 将使用下一代测序技术分析连锁基因， 进行可视化X染色体拷贝数和XIST表达，X失活的标志物， 未培养的组织切片。确定单克隆的频率对于肿瘤样细胞是至关重要的。 PAH发病机制的模型和X染色体的其他异常可能部分解释了 女性发病率高于男性。

Project Summary 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.