Background:Pulmonary arterial hypertension is an incurable disease, in which the extracellular CaSR (calcium sensing receptor) is mechanistically important. This study was aimed to genetically link the CaSR gene and function to the disease severity.Methods:Sanger sequencing, Sugen/hypoxia pulmonary arterial hypertension rat model, CaSR mutated rat, transcriptional reporter assay and measurement of CaSR activity were used.Results:Sanger sequencing identified a significant association between the variant rs1042636(A>G), located in CaSR exon 7, and idiopathic pulmonary arterial hypertension (IPAH) formation in patients. The frequency of 2968G homozygotes was higher in patients with IPAH compared with healthy individuals (23.6% versus 17.5%; P=0.001, OR=1.864), and the minor alleles of rs6776158, rs1048213, and rs9883099, located in CaSR promoter, raised the IPAH odds ratio to 2.173. Patients with IPAH carrying heterozygotes or homozygotes genotype of rs1042636 showed markedly higher pulmonary artery pressure and reduced survival compared with individuals carrying the wild-type allele. The minor alleles of rs6776158, rs1048213, and rs9883099 increased CaSR expression in reporter assay. In Sugen/hypoxia pulmonary arterial hypertension rats, the point mutation replicating rs1042636 found in IPAH exacerbated pulmonary arterial hypertension severity by promoting the overexpression and the enhanced activity of CaSR.Conclusions:Our functional genomic analysis thus indicates that the CaSR minor alleles of rs1042636, rs6776158, rs1048213, and rs9883099 contribute to the development and severity of IPAH. These findings may benefit clinical prognosis and treatment for IPAH.

中文翻译：

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钙敏感受体变异增加肺动脉高压易感性

背景：肺动脉高压是一种无法治愈的疾病，其中细胞外CaSR（钙敏感受体）在机制上很重要。本研究旨在将CaSR基因和功能与疾病严重程度进行遗传联系。方法：使用 Sanger 测序、Sugen/缺氧肺动脉高压大鼠模型、CaSR突变大鼠、转录报告基因测定和 CaSR 活性测量。结果：Sanger 测序发现位于CaSR外显子 7 的变体 rs1042636（A>G）与患者特发性肺动脉高压（IPAH）形成之间存在显着关联。与健康个体相比，IPAH 患者中 2968G 纯合子的频率更高（23.6% 对 17.5%；P=0.001，OR=1.864），位于CaSR启动子的rs6776158、rs1048213和rs9883099的次要等位基因将IPAH优势比提高到2.173。与携带野生型等位基因的个体相比，携带 rs1042636 杂合子或纯合子基因型的 IPAH 患者肺动脉压明显升高，存活率降低。rs6776158、rs1048213 和 rs9883099 的次要等位基因在报告基因检测中增加了 CaSR 的表达。在 Sugen/缺氧肺动脉高压大鼠中，在 IPAH 中发现的复制 rs1042636 的点突变通过促进 CaSR 的过表达和增强的活性加剧了肺动脉高压的严重程度。结论：我们的功能基因组分析表明，CaSRrs1042636、rs6776158、rs1048213 和 rs9883099 的次要等位基因有助于 IPAH 的发展和严重程度。这些发现可能有益于 IPAH 的临床预后和治疗。