Role of the X-chromosome in Pulmonary Arterial Hypertension

描述（由申请人提供）：肺动脉高压（PAH）是一种严重的肺部疾病，其特征为小肺动脉增生性变化，导致血管狭窄、肺动脉压升高和右心衰竭。越来越多的证据表明，PAH患者肺部的增殖性病变类似于肿瘤，具有单克隆扩增和遗传不稳定性。支持这一点，我们最近确定了PAH肺内皮细胞的染色体异常，包括16%的女性病例中的X染色体嵌合缺失。我们还发现了一个令人惊讶的高频率（32%）的非常歪斜的X-失活模式，这可能代表单克隆或重新激活的失活X染色体。在这项研究中，我们将在原代细胞培养和未培养的肺组织中进行X-失活的详细分析，以区分这两种假设，并确定X染色体缺失的病例是否丢失了活性或非活性X。将使用下一代测序分析X连锁基因的等位基因特异性表达，并将进行原位杂交以可视化未培养组织切片中的X染色体拷贝数和XIST表达（X失活的标志物）。确定单克隆频率对于PAH发病机制的肿瘤样模型至关重要，X染色体的其他异常可能部分解释了女性的发生率高于男性。 公共卫生相关性：肺动脉高压（PAH）是一种严重的、可能危及生命的肺部疾病，病因复杂。本研究将使用接受肺移植的PAH患者的肺组织来表征疾病过程中发生的X染色体变化。长期目标是了解PAH如何发展并设计更有效的治疗方法。(End摘要）

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)