Germline and Somatic Genetic Changes in Pulmonary Arterial Hypertension

 描述(由申请人提供)：肺动脉高压(PAH)是一种严重的心肺疾病，其特征是小动脉进行性狭窄和肺动脉压力升高，可导致右心衰竭。通过对易感基因的鉴定，人们已经对这种罕见的家族性形式有了很多了解，但在先天性心脏病或结缔组织疾病的背景下，相关的PAH(APAH)的分子基础仍然很大程度上是未知的。即使在家族性PAH中，这些突变的外显率也很低，而且导致PAH病因的额外遗传或环境因素还不是很清楚。我们的方法侧重于了解导致PAH的种系遗传变异，以及可能导致疾病发生和/或发展的肺部躯体变化。我们发现，在从外植体肺组织分离的肺动脉内皮细胞(PAEC)中，三分之一的PAH病例存在大规模的染色体异常。这是一个最低估计，因为可能有更细微的变化低于我们迄今执行的分析的分辨率。PAH细胞的DNA损伤水平明显高于对照组，不仅在PAEC中，而且在外周血单个核细胞(PBMC)中也是如此。损伤程度与活性氧(ROS)含量密切相关。患者的细胞对DNA破坏性化疗药物的敏感性也明显高于对照组。类似的异常也见于遗传性、特发性和相关的PAH病例。值得注意的是，我们发现患者亲属的PBMC表现出相同的ROS产生增加、诱变剂敏感性和DNA损伤的特征，这表明这可能是一种遗传决定的特征。我们的中心假设是，PAH患者具有先于PAH发病的DNA损伤的内在易感性，容易发生基因改变，导致血管内皮细胞损伤后的血管重塑。本研究的目的是(1)确定PAH细胞DNA损伤和修复的轮廓，(2)确定ROS增加和DNA损伤的分子基础，(3)确定导致PAH细胞DNA损伤增加的遗传因素。

 DESCRIPTION (provided by applicant): Pulmonary arterial hypertension (PAH) is a serious cardiopulmonary disease characterized by progressive narrowing of the small pulmonary arteries and elevated pulmonary artery pressure, which can lead to right heart failure. Much has been learned about the rare familial form by the identification of predisposing genes, but the molecular basis of associated PAH (APAH) in the context of congenital heart defects or connective tissue disorder remains largely unknown. Even in familial PAH, the penetrance of these mutations is low and the additional genetic or environmental factors that contribute to the etiology of PAH are not well understood. Our approach focuses on understanding both the germline genetic variation that predisposes to PAH and also somatic changes arising within the lung that may contribute to the onset and/or progression of the disease. We have shown that in pulmonary artery endothelial cells (PAEC) isolated from explant lung tissue, one-third of PAH cases harbor large-scale chromosome abnormalities. This is a minimum estimate, since there are likely more subtle alterations that are below the resolution of the analyses we have performed thus far. Levels of DNA damage were markedly higher in PAH cells than controls, not only in PAEC but also in peripheral blood mononuclear cells (PBMC). The level of damage correlated strongly with the amount of reactive oxygen species (ROS). Patients' cells were also significantly more sensitive to DNA damaging chemotherapeutic agents than controls. Similar abnormalities were seen across heritable, idiopathic and associated PAH cases. Remarkably, we discovered that PBMC from relatives of patients show the same profile of increased ROS production, mutagen sensitivity and DNA damage, suggesting that it may be a genetically determined trait. Our central hypothesis is that PAH patients share an intrinsic susceptibility to DNA damage that pre-dates the onset of PAH, predisposing to genetic alterations that contribute to vascular remodeling following endothelial cell injury. The aims of this study are to (1) determine the profile of DNA damage and repair in PAH cells, (2) identify the molecular basis of increased ROS and DNA damage, and (3) identify the genetic factors underlying increased DNA damage in PAH.