Rbm20-deficient cardiogenesis reveals early disruption of RNA processing and sarcomere remodeling establishing a developmental etiology for dilated cardiomyopathy
Rbm20-deficient cardiogenesis reveals early disruption of RNA processing and sarcomere remodeling establishing a developmental etiology for dilated cardiomyopathy
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DOI：
10.1093/hmg/ddu091
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发表时间：
2014-07-15
影响因子：
3.5
通讯作者：
Nelson, Timothy J.
中科院分区：
文献类型：
--
作者：
Beraldi, Rosanna;Li, Xing;Nelson, Timothy J.
扩张型心肌病(DCM)是由编码RNA结合蛋白的基因RBM20突变引起的，与高家族外显性、进行性心力衰竭和猝死的风险有关。虽然遗传学研究和生理学模型已经建立了RBM20与早发性DCM的联系，但细胞和分子功能障碍的潜在基础尚不确定。在此，使用高通量多能干细胞平台对人类遗传学进行建模，旨在查明疾病发病机制中最初的转录组功能障碍和机械性腐败。将TnNT2-pGreenZeo多能干细胞用于敲除RBM20(ShRbm20)，以确定心脏分化过程中的心脏致病表型。细胞内Ca~(2+)瞬变显示在处理Ca~(2+)的过程中依赖于RBM20，这与心脏发生24天时已知的titin和Camk2d基因的病理剪接变异相一致。超微结构分析显示，在没有RBM20的情况下，肌节延长和变薄，这与人类心脏活检样本一致。此外，第12天的RBM20缺失转录图谱证实了RBM20依赖的失调，76%的差异表达基因与已知的心脏病理相关，范围从原始的NKX2.5到成熟的心脏Tnnt2作为初始分子异常。值得注意的是，分化第24天RBM20缺失的下游结果显示细胞外基质成分显著失调，如VTN基因异常过表达。通过使用多能干细胞平台根据特定阶段的心源性路线图来模拟人类心脏病，我们建立了家族性DCM发病机制的新范式，作为一种发育障碍，在心脏发生的早期形成模式，并随着病理性心脏重塑的细胞机制而传播。
Dilated cardiomyopathy (DCM) due to mutations in RBM20, a gene encoding an RNA-binding protein, is associated with high familial penetrance, risk of progressive heart failure and sudden death. Although genetic investigations and physiological models have established the linkage of RBM20 with early-onset DCM, the underlying basis of cellular and molecular dysfunction is undetermined. Modeling human genetics using a high-throughput pluripotent stem cell platform was herein designed to pinpoint the initial transcriptome dysfunction and mechanistic corruption in disease pathogenesis. Tnnt2-pGreenZeo pluripotent stem cells were engineered to knockdown Rbm20 (shRbm20) to determine the cardiac-pathogenic phenotype during cardiac differentiation. Intracellular Ca2+ transients revealed Rbm20-dependent alteration in Ca2+ handling, coinciding with known pathological splice variants of Titin and Camk2d genes by Day 24 of cardiogenesis. Ultrastructural analysis demonstrated elongated and thinner sarcomeres in the absence of Rbm20 that is consistent with human cardiac biopsy samples. Furthermore, Rbm20-depleted transcriptional profiling at Day 12 identified Rbm20-dependent dysregulation with 76% of differentially expressed genes linked to known cardiac pathology ranging from primordial Nkx2.5 to mature cardiac Tnnt2 as the initial molecular aberrations. Notably, downstream consequences of Rbm20-depletion at Day 24 of differentiation demonstrated significant dysregulation of extracellular matrix components such as the anomalous overexpression of the Vtn gene. By using the pluripotent stem cell platform to model human cardiac disease according to a stage-specific cardiogenic roadmap, we established a new paradigm of familial DCM pathogenesis as a developmental disorder that is patterned during early cardiogenesis and propagated with cellular mechanisms of pathological cardiac remodeling.