Somatic ATP1A1, ATP2B3, and KCNJ5 Mutations in Aldosterone-Producing Adenomas
Somatic ATP1A1, ATP2B3, and KCNJ5 Mutations in Aldosterone-Producing Adenomas
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DOI：
10.1161/hypertensionaha.113.01733
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发表时间：
2014-01-01
期刊：
影响因子：
8.3
通讯作者：
Mulatero, Paolo
中科院分区：
文献类型：
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作者：
Williams, Tracy Ann;Monticone, Silvia;Mulatero, Paolo
产生醛固酮的腺瘤（APA）引起散发形式的原发性醛固酮增多症，并且编码G蛋白激活的内向整流性K+通道4（GIRK 4）的KCNJ 5基因中的体细胞突变占APA的约40%。最近在另外2个基因（分别编码Na+/K+-ATP酶1和Ca 2 +-ATP酶3的ATP 1A 1和ATP 2B 3）中发现了额外的体细胞阿帕突变，合并患病率为6.8%。我们已经筛选了112个APA突变的已知热点与原发性醛固酮增多症相关的遗传改变。ATP 1A 1、ATP 2B 3和KCNJ 5的体细胞突变分别存在于6.3%、0.9%和39.3%的APA中，并且包括2个新突变（Na+/K+-ATP酶p.Gly99Arg和GIRK 4 p.Trp126Arg）。与无ATP 1A 1和ATP 2B 3突变或KCNJ 5突变的APA相比，携带ATP 1A 1和ATP 2B 3突变的APA的CYP 11B 2基因表达更高。Na+/K+-ATP酶p.Gly99Arg和GIRK 4 p.Trp126Arg在HAC 15肾上腺细胞中的过表达导致CYP 11B 2基因及其转录调节因子NR 4A 2的表达上调。Na+/K+-ATP酶的结构建模表明，Gly 99 Arg取代最有可能干扰离子结合口袋的网关。在体外功能测定表明，Gly 99 Arg显示严重受损的ATP酶活性，降低的表观亲和力Na+激活磷酸化和K+抑制磷酸化，表明减少Na+和K+结合，分别。此外，全细胞膜片钳研究证实，Na+/K+-ATP酶Gly 99 Arg的过度表达引起膜电压去极化。总之，体细胞突变在APA中很常见，导致CYP 11B 2基因表达增加，并可能导致散发性原发性醛固酮增多症患者亚组的醛固酮产生失调。
Aldosterone-producing adenomas (APAs) cause a sporadic form of primary aldosteronism and somatic mutations in the KCNJ5 gene, which encodes the G-protein-activated inward rectifier K+ channel 4, GIRK4, account for approximate to 40% of APAs. Additional somatic APA mutations were identified recently in 2 other genes, ATP1A1 and ATP2B3, encoding Na+/K+-ATPase 1 and Ca2+-ATPase 3, respectively, at a combined prevalence of 6.8%. We have screened 112 APAs for mutations in known hotspots for genetic alterations associated with primary aldosteronism. Somatic mutations in ATP1A1, ATP2B3, and KCNJ5 were present in 6.3%, 0.9%, and 39.3% of APAs, respectively, and included 2 novel mutations (Na+/K+-ATPase p.Gly99Arg and GIRK4 p.Trp126Arg). CYP11B2 gene expression was higher in APAs harboring ATP1A1 and ATP2B3 mutations compared with those without these or KCNJ5 mutations. Overexpression of Na+/K+-ATPase p.Gly99Arg and GIRK4 p.Trp126Arg in HAC15 adrenal cells resulted in upregulation of CYP11B2 gene expression and its transcriptional regulator NR4A2. Structural modeling of the Na+/K+-ATPase showed that the Gly99Arg substitution most likely interferes with the gateway to the ion binding pocket. In vitro functional assays demonstrated that Gly99Arg displays severely impaired ATPase activity, a reduced apparent affinity for Na+ activation of phosphorylation and K+ inhibition of phosphorylation that indicate decreased Na+ and K+ binding, respectively. Moreover, whole cell patch-clamp studies established that overexpression of Na+/K+-ATPase Gly99Arg causes membrane voltage depolarization. In conclusion, somatic mutations are common in APAs that result in an increase in CYP11B2 gene expression and may account for the dysregulated aldosterone production in a subset of patients with sporadic primary aldosteronism.