Common human ANK2 variant confers in vivo arrhythmia phenotypes

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• 作者：Hassan Musa ; PhD^* ; ^&dagger ; ; Nathaniel P. Murphy ; BS^* ; ^&dagger ; ; Jerry Curran ; PhD^* ; ^&dagger ; ; John D. Higgins ; BS^* ; ^&dagger ; ; Tyler R. Webb^* ; ^&dagger ; ; Michael A. Makara ; PhD^* ; ^&dagger ; ; Patrick Wright ; BS^* ; Peter J. Lancione ; BS^* ; ^&dagger ; ; Ellen R. Lubbers ; BS^* ; ^&dagger ; ; Jane A. Healy ; BS^&Dagger ; ; Sakima A. Smith ; MD^* ; ^&sect ; ; Vann Bennett ; MD ; PhD^&Dagger ; ; Thomas J. Hund ; PhD^* ; ^&sect ; ; ^║ ; Crystal F. Kline ; PhD^* ; ^&dagger ; ; Peter J. Mohler ; PhD^* ; ^&dagger ; ; ^&sect ; ; ^{peter.mohler@osumc.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Ankyrin ; Arrhythmia ; Ion channel ; Myocyte ; Mouse models of disease
• 刊名：Heart Rhythm
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：13
• 期：9
• 页码：1932-1940
• 全文大小：1453 K

文摘

Human ANK2 (ankyrin-B) loss-of-function variants are directly linked with arrhythmia phenotypes. However, in atypical non–ion channel arrhythmia genes such as ANK2 that lack the same degree of robust structure/function and clinical data, it may be more difficult to assign variant disease risk based simply on variant location, minor allele frequency, and/or predictive structural algorithms. The human ankyrin-B p.L1622I variant found in arrhythmia probands displays significant diversity in minor allele frequency across populations.

c_2">Objective

The objective of this study was to directly test the in vivo impact of ankyrin-B p.L1622I on cardiac electrical phenotypes and arrhythmia risk using a new animal model.

c_3">Methods

We tested arrhythmia phenotypes in a new “knock-in” animal model harboring the human ankyrin-B p.L1622I variant.

c_4">Results

Ankyrin-B p.L1622I displays reduced posttranslational expression in vivo, resulting in reduced cardiac ankyrin-B expression and reduced association with binding-partner Na/Ca exchanger. Ankyrin-B^{L1622I/L1622I} mice display changes in heart rate, atrioventricular and intraventricular conduction, and alterations in repolarization. Furthermore, ankyrin-B^{L1622I/L1622I} mice display catecholamine-dependent arrhythmias. At the cellular level, ankyrin-B^{L1622I/L1622I} myocytes display increased action potential duration and severe arrhythmogenic afterdepolarizations that provide a mechanistic rationale for the arrhythmias.

c_5">Conclusion

Our findings support in vivo arrhythmogenic phenotypes of an ANK2 variant with unusual frequency in select populations. On the basis of our findings and current clinical data, we support classification of p.L1622I as a “mild” loss-of-function variant that may confer arrhythmia susceptibility in the context of secondary risk factors including environment, medication, and/or additional genetic variation.