The Role of MAPRE2 and Microtubules in Maintaining Normal Ventricular Conduction.
The Role of MAPRE2 and Microtubules in Maintaining Normal Ventricular Conduction.
复制标题
MAPRE2 和微管在维持正常心室传导中的作用。
DOI：
10.1161/circresaha.123.323231
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发表时间：
2024
影响因子：
20.1
通讯作者：
Kiviniemi,Tu
中科院分区：
文献类型：
--
作者：
Chiang,DavidY;Verkerk,ArieO;Victorio,Rachelle;Shneyer,BorisI;vanderVaart,Babet;Jouni,Mariam;Narendran,Nakul;Kc,Ashmita;Sampognaro,JamesR;Vetrano-Olsen,Franki;Oh,JohnS;Buys,Eva;deJonge,Berend;Shah,DisheetA;Kiviniemi,Tu
BACKGROUNDBrugada syndrome is associated with loss-of-functionSCN5Avariants, yet these account for only ≈20% of cases. A recent genome-wide association study identified a novel locus withinMAPRE2, which encodes EB2 (microtubule end-binding protein 2), implicating microtubule involvement in Brugada syndrome.METHODSAmapre2knockout zebrafish model was generated using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat–associated protein 9) and validated by Western blot. Larval hearts at 5 days post-fertilization were isolated for voltage mapping and immunocytochemistry. Adult fish hearts were used for ECG, patch clamping, and immunocytochemistry. Morpholinos were injected into embryos at 1-cell stage for knockdown experiments. A transgenic zebrafish line withcdh2tandem fluorescent timer was used to study adherens junctions. Microtubule plus-end tracking and patch clamping were performed in human induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs) withMAPRE2knockdown and knockout, respectively.RESULTSVoltage mapping ofmapre2knockout hearts showed a decrease in ventricular maximum upstroke velocity of the action potential and conduction velocity, suggesting loss of cardiac voltage-gated sodium channel function. ECG showed QRS prolongation in adult knockout fish, and patch clamping showed decreased sodium current density in knockout ventricular myocytes and arrhythmias in knockout iPSC-CMs. Confocal imaging showed disorganized adherens junctions and mislocalization of mature Ncad (N-cadherin) withmapre2loss of function, associated with a decrease of detyrosinated tubulin.MAPRE2knockdown in iPSC-CMs led to an increase in microtubule growth velocity and distance, indicating changes in microtubule dynamics. Finally, knockdown ofttlencoding tubulin tyrosine ligase inmapre2knockout larvae rescued tubulin detyrosination and ventricular maximum upstroke velocity of the action potential.CONCLUSIONSGenetic ablation ofmapre2led to a decrease in voltage-gated sodium channel function, a hallmark of Brugada syndrome, associated with disruption of adherens junctions, decrease of detyrosinated tubulin as a marker of microtubule stability, and changes in microtubule dynamics. Restoration of the detyrosinated tubulin fraction withttlknockdown led to rescue of voltage-gated sodium channel–related functional parameters inmapre2knockout hearts. Taken together, our study implicates microtubule dynamics in the modulation of ventricular conduction.
