携带线粒体tRNA^(Met)4435A>G和核基因YARS2突变的原发性高血压家系遗传学分析

Clinical and genetic analysis of essential hypertension with mitochondrial tRNA^(Met)4435A>G and YARS2 mutation

目的:探讨m.4435A>G和YARS2 c.572G>T(p.G191V)突变在原发性高血压发生发展中的作用。方法:分析前期收集的高血压患者的线粒体基因组及外显子测序数据,对一例携带m.4435A>G和YARS2 p.G191V突变的原发性高血压患者的家系开展临床资料采集及分子遗传学检测,收集外周静脉血并构建永生化淋巴细胞系进行线粒体转移RNA(tRNA)、线粒体蛋白质、腺苷三磷酸(ATP)、线粒体膜电位(MMP)和细胞内活性氧检测。结果:线粒体全基因组测序结果显示,该家系中母系成员均携带高度保守的m.4435A>G突变,该突变影响线粒体tRNA的二级结构和折叠自由能并改变其稳定性,预测其将影响反密码子环结构。与对照组比较,携带m.4435A>G和YARS2 p.G191V突变的细胞株相关线粒体tRNA稳态水平、部分线粒体蛋白表达量、ATP产量和MMP水平下降,且活性氧水平升高,差异均有统计学意义(均P<0.05)。结论:YARS2 p.G191V突变通过影响线粒体tRNA稳态水平加重了m.4435A>G引起的线粒体翻译及线粒体功能改变,进一步导致细胞功能障碍,表明在本家系中YARS2 p.G191V与m.4435A>G突变存在协同作用,共同参与原发性高血压的发生发展。

Objective:To investigate the role of m.4435A>G and YARS2 c.572G>T(p.G191V)mutations in the development of essential hypertension.Methods:A hypertensive patient with m.4435A>G and YARS2 p.G191V mutations was identified from previously collected mitochondrial genome and exon sequencing data.Clinical data were collected,and a molecular genetic study was conducted in the proband and his family members.Peripheral venous blood was collected,and immortalized lymphocyte lines constructed.The mitochondrial transfer RNA(tRNA),mitochondrial protein,adenosine triphosphate(ATP),mitochondrial membrane potential(MMP),and reactive oxygen species(ROS)in the constructed lymphocyte cell lines were measured.Results:Mitochondrial genome sequencing showed that all maternal members carried a highly conserved m.4435A>G mutation.The m.4435A>G mutation might affect the secondary structure and folding free energy of mitochondrial tRNA and change its stability,which may influence the anticodon ring structure.Compared with the control group,the cell lines carrying m.4435A>G and YARS2 p.G191V mutations had decreased mitochondrial tRNA homeostasis,mitochondrial protein expression,ATP production and MMP levels,as well as increased ROS levels(all P<0.05).Conclusion:The YARS2 p.G191V mutation aggravates the changes in mitochondrial translation and mitochondrial function caused by m.4435A>G through affecting the steady-state level of mitochondrial tRNA and further leads to cell dysfunction,indicating that YARS2 p.G191V and m.4435A>G mutations have a synergistic effect in this family and jointly participate in the occurrence and development of essential hypertension.