Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Division of Cardiology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Acta Physiol (Oxf). 2021 Apr;231(4):e13604. doi: 10.1111/apha.13604. Epub 2020 Dec 29.
To investigate the role of zinc finger homeobox 3 gene (ZFHX3) in tachypacing-induced mitochondrial dysfunction and explore its molecular mechanisms and potential as a therapeutic target in atrial fibrillation (AF).
Through a bioluminescent assay, a patch clamp, confocal fluorescence and fluorescence microscopy, microplate enzyme activity assays and Western blotting, we studied ATP and ADP production, mitochondrial electron transfer chain complex activities, ATP-sensitive potassium channels (I ), mitochondrial oxidative stress, Ca content, and protein expression in control and ZFHX3 knockdown (KD) HL-1 cells subjected to 1 and 5-Hz pacing for 24 hours.
Compared with 1-Hz pacing, 5-Hz pacing increased ATP and ADP production, I , phosphorylated adenosine monophosphate-activated protein kinase and inositol 1,4,5-triphosphate (IP ) receptor (IP R) protein expression. Tachypacing induced mitochondrial oxidative stress and Ca overload in both cell types. Furthermore, under 1- and 5-Hz pacing, ZFHX3 KD cells showed higher I , ATP and ADP production, mitochondrial oxidative stress and Ca content than control cells. Under 5-Hz pacing, 2-aminoethoxydiphenyl borate (2-APB; 3 μmol/L, an IP R inhibitor) and MitoTEMPO (10 µmol/L, a mitochondria-targeted antioxidant) reduced ADP and increased ATP production in both cell types; however, only 2-APB significantly reduced mitochondrial Ca overload in control cells. Under 5-Hz pacing, mitochondrial oxidative stress was significantly reduced by both MitoTEMPO and 2-APB and only by 2-APB in control and ZFHX3 KD cells respectively.
ZFHX3 KD cells modulate mitochondrial adaptations to tachypacing in HL-1 cardiomyocytes through Ca overload, oxidative stress and metabolic disorder. Targeting IP R signalling or oxidative stress could reduce AF.
探讨锌指同源盒 3 基因（ZFHX3）在快速起搏诱导的线粒体功能障碍中的作用，并探讨其在心房颤动（AF）中的分子机制和作为治疗靶点的潜力。
通过生物发光测定法、膜片钳、共聚焦荧光和荧光显微镜、微量板酶活性测定法和 Western blot 法，我们研究了对照和 ZFHX3 敲低（KD）HL-1 细胞在 1 和 5-Hz 起搏 24 小时后 ATP 和 ADP 的产生、线粒体电子传递链复合物活性、ATP 敏感性钾通道（I ）、线粒体氧化应激、Ca 含量和蛋白表达。
与 1-Hz 起搏相比，5-Hz 起搏增加了 ATP 和 ADP 的产生、I 、磷酸化的腺苷一磷酸激活蛋白激酶和肌醇 1,4,5-三磷酸（IP ）受体（IP R）蛋白的表达。快速起搏导致两种细胞类型中线粒体氧化应激和 Ca 超载。此外，在 1-和 5-Hz 起搏下，ZFHX3 KD 细胞的 I 、ATP 和 ADP 产生、线粒体氧化应激和 Ca 含量均高于对照细胞。在 5-Hz 起搏下，2-氨基乙氧基二苯硼酸盐（2-APB；3 μmol/L，IP R 抑制剂）和 MitoTEMPO（10 μmol/L，线粒体靶向抗氧化剂）降低了两种细胞类型的 ADP 并增加了 ATP 的产生；然而，只有 2-APB 显著降低了对照细胞中线粒体 Ca 的超载。在 5-Hz 起搏下，MitoTEMPO 和 2-APB 均显著降低了线粒体氧化应激，而仅 2-APB 降低了对照和 ZFHX3 KD 细胞中的线粒体氧化应激。
ZFHX3 KD 细胞通过 Ca 超载、氧化应激和代谢紊乱调节 HL-1 心肌细胞对快速起搏的线粒体适应。靶向 IP R 信号或氧化应激可能减少 AF。
