Mutation Specific Therapies in Patients with HPAH

产品说明：肺动脉高压（PAH）患者的既定治疗方法均不能降低死亡率或逆转既定的肺血管病变。然而，遗传性PAH（HPAH）患者在BMP 2型受体基因BMPR 2中遗传杂合常染色体显性突变，这表明纠正BMP信号传导缺陷的策略可能为这种疾病提供新的治疗方法。已经鉴定了超过300种HPAH BMPR 2突变，每种突变对BMPR 2功能具有潜在的不同影响。然而，这些可以分为3个功能组：i）I类：mRNA通过无义介导的RNA降解（NMD+）降解; ii）II类：受体表达（NMD-），但错误折叠，不在细胞表面上表达;和iii）III类：受体表达（NMD-），并正确定位，但无功能。这种分类是重要的，因为NMD抑制剂可以恢复具有I类突变的BMP信号传导，而纠正蛋白质折叠的化合物可以恢复具有II类但不具有III类BMPR 2突变的信号传导。重要的是，NMD抑制剂和蛋白质折叠剂都是有效、安全的，并且正在其他遗传性疾病（如囊性纤维化）患者中进行评估。这些研究将确定突变特异性疗法是否也能纠正HPAH患者的BMPR 2表达和功能。作为建立这种模式在HPAH中的适用性的第一步，我们将使用HPAH患者来源的内皮细胞（EC）。理想情况下，我们将使用来自HPAH患者的肺内皮细胞（佩奇）进行所有这些研究。然而，这些细胞供应有限，并且在培养中寿命短。出于这个原因，我们将补充使用从PHBI细胞核心获得的HPAH佩奇的初始研究，使用从具有已知BMPR 2突变的HPAH患者的外周血获得的晚期生长内皮祖细胞（LEPC）的研究。其中一些细胞已经生成，将由一个合作者提供。然而，我们在范德比尔特处于独特的地位，可以使用来自美国最大的具有确定BMPR 2突变的HPAH患者队列的样本来补充这些研究。通过这种方式，我们将能够研究一组HPAH患者来源的EC，其包括来自所有3种功能性突变类别的BMPR 2突变的代表性分布。因此，使用这些细胞，我们将确定BMPR 2突变的性质和功能分类，并评估NMD通路抑制剂和蛋白折叠剂对这些HPAH患者BMPR 2表达和功能的影响。因此，这些研究将鉴定BMPR 2突变亚型和相关细胞类型中对NMD途径或蛋白质折叠疗法的响应性，并将形成对治疗靶向BMPR 2突变进行分类和对HPAH中的NMD抑制剂和/或蛋白质折叠剂进行更广泛评估的基础。

DESCRIPTION: None of the established therapies for patients with Pulmonary Arterial Hypertension (PAH) reduce mortality or reverse established pulmonary vasculopathy. However, patients with Hereditary PAH (HPAH) inherit heterozygous, autosomal dominant mutations in the BMP type 2 receptor gene, BMPR2, suggesting that strategies to correct BMP signaling defects could present a new therapeutic approach for this disease. Over 300 HPAH BMPR2 mutations have been identified, each with potentially different effects on BMPR2 function. However, these can be classified into 3 functional groups: i) Class I: mRNA is degraded by non-sense mediated RNA decay, (NMD+); ii) Class II: receptors are expressed (NMD-), but mis-folded and are not expressed on the cell surface; and iii) Class III: receptors are expressed (NMD-) and correctly localized but non functional. This classification is important since NMD inhibitors may restore BMP signaling with Class I mutations, while compounds that correct protein folding may restore signaling with Class II but not Class III BMPR2 mutations. Importantly, both NMD inhibitors and protein folding agents, are effective, safe and being evaluated in patients with other heritable diseases, such as cystic fibrosis. These studies will determine whether mutation-specific therapies also correct BMPR2 expression and function in HPAH patients. As an initial step to establish the applicability of this paradigm in HPAH, we will use HPAH patient-derived endothelial cells (ECs). Ideally we would use pulmonary endothelial cells (PECs) from HPAH patients for all of these studies. However these cells are in limited supply and have short lifespan in culture. For this reason we will supplement initial studies using HPAH PECs obtained from the PHBI Cell Core, with studies using late outgrowth endothelial progenitor cells (LEPCs) obtained from peripheral blood of HPAH patients with known BMPR2 mutations. Some of these cells have been generated and will be provided by a collaborator. However, we are in a unique position at Vanderbilt to supplement these studies using samples derived from the largest cohort of HPAH patients with defined BMPR2 mutations in the USA. In this way we will be able to study a cohort of HPAH patient-derived ECs that include a representative distribution of BMPR2 mutations from all 3 functional classes of mutation. Using these cells therefore, we will determine the nature and functional classification of BMPR2 mutations, and evaluate the effects of NMD pathway inhibitors and protein folding agents on BMPR2 expression and function in these HPAH patients. These studies therefore will identify BMPR2 mutant sub-types and responsiveness to NMD pathway or protein folding therapy in a relevant cell type, and will form the foundation to classify therapeutically targetable BMPR2 mutations and more extensive evaluation of NMD inhibitors and/or protein folding agents in HPAH.