Linseman Tara, Soubeyrand Sébastien, Martinuk Amy, Nikpay Majid, Lau Paulina, McPherson Ruth
From the Atherogenomics Laboratory, University of Ottawa Heart Institute, Canada.
Circ Cardiovasc Genet. 2017 Jan;10(1). doi: 10.1161/CIRCGENETICS.116.001498.
Although virtually all coronary artery disease associated single-nucleotide polymorphisms identified by genome-wide association studies (GWAS) are in noncoding regions of the genome, a common polymorphism in ZC3HC1 (rs11556924), resulting in an arginine (Arg) to histidine (His) substitution in its encoded protein, NIPA (Nuclear Interacting Partner of Anaplastic Lyphoma Kinase) is linked to a protection from coronary artery disease. NIPA plays a role in cell cycle progression, but the functional consequences of this polymorphism have not been established.
Here we demonstrate that total ZC3HC1 expression in whole blood is similar across genotypes, despite expression being slightly biased toward the risk allele in heterozygotes. At the protein level, the protective His363 NIPA variant exhibits increased phosphorylation of a critical serine residue (Ser354) and higher protein expression as compared with the Arg363 variant. Binding experiments indicate that neither SKP1 (S-phase kinase-associated protein 1) nor CCNB1 binding were affected by the polymorphism. Despite similar nuclear distribution, NIPA His363 exhibits greater nuclear mobility. NIPA suppression results in a modest reduction of proliferation in vascular smooth muscle cells, but given low proliferative capacity, a significant effect of the variant was not noted. By contrast, we demonstrate that the protective variant reduces cell proliferation in HeLa cells.
These findings extend the genetic association between rs11556924 and coronary artery disease risk by characterizing its effects on the encoded protein, NIPA. The resulting amino acid change Arg363His is associated with increased expression and nuclear mobility, as well as lower rates of cell growth in HeLa cells, further supporting a role for cell proliferation in atherosclerosis and its clinical consequences.
尽管通过全基因组关联研究（GWAS）确定的几乎所有与冠状动脉疾病相关的单核苷酸多态性都位于基因组的非编码区域，但ZC3HC1基因中的一个常见多态性（rs11556924），导致其编码蛋白NIPA（间变性淋巴瘤激酶的核相互作用伴侣）中的精氨酸（Arg）被组氨酸（His）取代，与预防冠状动脉疾病有关。NIPA在细胞周期进程中发挥作用，但这种多态性的功能后果尚未明确。
在此我们证明，尽管杂合子中全血中ZC3HC1的总表达略微偏向风险等位基因，但不同基因型间全血中ZC3HC1的总表达相似。在蛋白质水平上，与Arg363变体相比，具有保护作用的His363 NIPA变体表现出关键丝氨酸残基（Ser354）磷酸化增加和蛋白质表达更高。结合实验表明，该多态性不影响SKP1（S期激酶相关蛋白1）或CCNB1的结合。尽管核分布相似，但NIPA His363表现出更大的核迁移率。NIPA抑制导致血管平滑肌细胞增殖适度减少，但鉴于其增殖能力较低，未观察到该变体的显著影响。相比之下，我们证明该保护性变体可降低HeLa细胞的增殖。
这些发现通过表征rs11556924对其编码蛋白NIPA的影响，扩展了其与冠状动脉疾病风险之间的遗传关联。由此产生的氨基酸变化Arg363His与HeLa细胞中表达增加、核迁移率提高以及细胞生长速率降低相关，进一步支持了细胞增殖在动脉粥样硬化及其临床后果中的作用。
