心律失常性心肌病(ACM)是一种遗传性心肌疾病,由编码核包膜蛋白跨膜蛋白43(TMEM43)的基因内杂合子错义突变引起。该疾病的特征是肌细胞丢失和纤维脂肪替代,导致危及生命的室性心律失常和心源性猝死.然而,TMEM43在ACM发病机制中的作用尚不清楚.在这项研究中,我们产生了心肌细胞限制性转基因斑马鱼品系,该品系过表达eGFP连锁的全长人野生型(WT)TMEM43和两个遗传变异体(c.1073C>T,p.S358L;c.333C>T,p.P111L)使用Tol2系统。WT和p.P111L-突变型TMEM43的过表达与mTOR通路的转录激活和核糖体生物发生相关,导致心肌肥大。有趣的是,发现突变体p.S358LTMEM43不稳定,并部分重新分布到胚胎和成年心脏的细胞质中。此外,两种TMEM43变体在幼年阶段都显示出心脏形态缺陷和心肌内的超微结构变化,伴随着成年期基因表达谱失调。最后,CRISPR/Cas9突变体表现出年龄依赖性心脏表型,其特征为成年后心脏增大。总之,我们的研究结果表明,超微结构重塑和转录组改变是TMEM43相关心肌病结构和功能性心脏缺陷发展的基础.
Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disease caused by heterozygous missense mutations within the gene encoding for the nuclear envelope protein transmembrane protein 43 (
TMEM43). The disease is characterized by myocyte loss and fibro-fatty replacement, leading to life-threatening ventricular arrhythmias and sudden cardiac death. However, the role of
TMEM43 in the pathogenesis of ACM remains poorly understood. In this study, we generated cardiomyocyte-restricted transgenic zebrafish lines that overexpress eGFP-linked full-length human wild-type (WT) TMEM43 and two genetic variants (c.1073C>T, p.S358L; c.332C>T, p.P111L) using the Tol2-system. Overexpression of WT and p.P111L-mutant
TMEM43 was associated with transcriptional activation of the mTOR pathway and ribosome biogenesis, and resulted in enlarged hearts with cardiomyocyte hypertrophy. Intriguingly, mutant p.S358L
TMEM43 was found to be unstable and partially redistributed into the cytoplasm in embryonic and adult hearts. Moreover, both
TMEM43 variants displayed cardiac morphological defects at juvenile stages and ultrastructural changes within the myocardium, accompanied by dysregulated gene expression profiles in adulthood. Finally, CRISPR/Cas9 mutants demonstrated an age-dependent cardiac phenotype characterized by heart enlargement in adulthood. In conclusion, our findings suggest ultrastructural remodeling and transcriptomic alterations underlying the development of structural and functional cardiac defects in TMEM43-associated cardiomyopathy.