Shinlapawittayatorn Krekwit, Dudash Lynn A, Du Xi X, Heller Lisa, Poelzing Steven, Ficker Eckhard, Deschênes Isabelle
Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, OH 44109, USA.
Circ Cardiovasc Genet. 2011 Oct;4(5):500-9. doi: 10.1161/CIRCGENETICS.111.960633. Epub 2011 Aug 12.
Brugada syndrome (BrS) is associated with mutations in the cardiac sodium channel (Na(v)1.5). We previously reported that the function of a trafficking-deficient BrS Na(v)1.5 mutation, R282H, could be restored by coexpression with the sodium channel polymorphism H558R. Here, we tested the hypothesis that peptide fragments from Na(v)1.5, spanning the H558R polymorphism, can be used to restore trafficking of trafficking-deficient BrS sodium channel mutations.
Whole-cell patch clamping revealed that cotransfection in human embryonic kidney (HEK293) cells of the R282H channel with either the 40- or 20-amino acid cDNA fragments of Na(v)1.5 containing the H558R polymorphism restored trafficking of this mutant channel. Fluorescence resonance energy transfer suggested that the trafficking-deficient R282H channel was misfolded, and this was corrected on coexpression with R558-containing peptides that restored trafficking of the R282H channel. Importantly, we also expressed the peptide spanning the H558R polymorphism with 8 additional BrS Na(v)1.5 mutations with reduced currents and demonstrated that the peptide was able to restore significant sodium currents in 4 of them.
In the present study, we demonstrate that small peptides, spanning the H558R polymorphism, are sufficient to restore the trafficking defect of BrS-associated Na(v)1.5 mutations. Our findings suggest that it might be possible to use short cDNA constructs as a novel strategy tailored to specific disease-causing mutants of BrS.
布加综合征（BrS）与心脏钠通道（Na(v)1.5）的突变有关。我们之前报道过，一种转运缺陷型的BrS钠通道突变R282H，与钠通道多态性H558R共表达时其功能可恢复。在此，我们验证了一个假说，即来自Na(v)1.5的跨越H558R多态性的肽片段可用于恢复转运缺陷型BrS钠通道突变的转运。
全细胞膜片钳记录显示，在人胚肾（HEK293）细胞中共转染R282H通道与包含H558R多态性的40个或20个氨基酸的Na(v)1.5 cDNA片段，可恢复该突变通道的转运。荧光共振能量转移表明，转运缺陷型的R282H通道发生了错误折叠，而与含R558的肽共表达时可纠正这一情况，该肽恢复了R282H通道的转运。重要的是，我们还将跨越H558R多态性的肽与另外8种电流减小的BrS Na(v)1.5突变体一起表达，结果表明该肽能够使其中4种突变体恢复显著的钠电流。
在本研究中，我们证明了跨越H558R多态性的小肽足以恢复与BrS相关的Na(v)1.5突变的转运缺陷。我们的研究结果表明，使用短cDNA构建体可能是针对BrS特定致病突变体的一种新型策略。
