Loss of function of hNav1.5 by a ZASP1 mutation associated with intraventricular conduction disturbances in left ventricular noncompaction.
Loss of function of hNav1.5 by a ZASP1 mutation associated with intraventricular conduction disturbances in left ventricular noncompaction.
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DOI：
10.1161/circep.111.969220
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发表时间：
2012-10
期刊：
影响因子：
--
通讯作者：
Vatta M
中科院分区：
文献类型：
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作者：
Xi Y;Ai T;De Lange E;Li Z;Wu G;Brunelli L;Kyle WB;Turker I;Cheng J;Ackerman MJ;Kimura A;Weiss JN;Qu Z;Kim JJ;Faulkner G;Vatta M
细胞结构蛋白的缺陷可导致左心室致密化不全（LVNC），这通常与传导系统疾病有关。我们以前已经确定了一个p.D117N突变的LDB 3编码Z-带选择性剪接PDZ基序基因（ZASP）的患者与LVNC和传导障碍。我们试图研究LBD 3 NM_001080114.1亚型（ZASP 1-D117 N）中p.D117 N突变在心脏钠通道（Nav1.5）调节中的作用，该通道在心脏传导系统中起重要作用。在HEK-293细胞和新生大鼠心肌细胞（NRCM）中研究了ZASP 1-wt和ZASP 1-D117 N对Nav1.5的影响。膜片钳研究表明，ZASP 1-D117 N在HEK-293细胞中显著减弱INa 27%，在NRCM中显著减弱INa 32%。此外，ZASP 1-D117 N使两个系统中的电压依赖性激活和失活发生了明显的偏移。使用Luo-Rudy阶段1模型的计算机模拟表明，与对照相比，Nav1.5功能改变可使心脏传导速度降低28%。Pull-down分析表明，wt和ZASP 1-D117 N都可以与Nav1.5和Telethonin/T-Cap复合，这需要完整的PDZ结构域。NRCM中的免疫组织化学染色表明ZASP 1-D117 N没有显著干扰Z线结构。用ML-7和细胞松弛素D破坏细胞骨架网络消除了ZASP 1-D117 N对Nav1.5的影响。ZASP 1可与Telethonin/T-Cap和Nav1.5形成蛋白复合物。LVNC特异性ZASP 1突变可导致Nav1.5功能丧失，而不会显著改变细胞骨架蛋白复合物。我们的研究表明，由于突变ZASP对Nav1.5的直接影响，LVNC受试者可能发生电重构。
Defects of cytoarchitectural proteins can cause left ventricular noncompaction (LVNC), which is often associated with conduction system diseases. We have previously identified a p.D117N mutation in the LDB3-encoding Z-band Alternatively Spliced PDZ motif gene (ZASP) in a patient with LVNC and conduction disturbances. We sought to investigate a role of p.D117N mutation in the LBD3 NM_001080114.1 isoform (ZASP1-D117N) in the regulation of cardiac sodium channel (Nav1.5) that plays an important role in the cardiac conduction system. Effects of ZASP1-wt and ZASP1-D117N on Nav1.5 were studied in HEK-293 cells and neonatal rat cardiomyocytes (NRCMs). Patch-clamp study demonstrated that ZASP1-D117N significantly attenuated INa by 27% in HEK-293 cells and by 32% in NRCMs. In addition, ZASP1-D117N rightward shifted the voltage-dependent activation and inactivation in both systems. In silico simulation using Luo-Rudy phase 1 model demonstrated that altered Nav1.5 function can reduce cardiac conduction velocity by 28% compared to the control. Pull-down assays showed that both wt and ZASP1-D117N can complex with Nav1.5 and telethonin/T-Cap, which required intact PDZ domains. Immunohistochemical staining in NRCMs demonstrates that ZASP1-D117N did not significantly disturb the Z-line structure. Disruption of cytoskeletal networks with ML-7 and cytochalasin D abolished the effects of ZASP1-D117N on the Nav1.5. ZASP1 can form protein complex with telethonin/T-Cap and Nav1.5. The LVNC-specific ZASP1 mutation can cause loss-of-function of Nav1.5 without significant alteration of the cytoskeletal protein complex. Our study suggests that electrical remodeling can occur in LVNC subject due to a direct effect of mutant ZASP on Nav1.5.