Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, via A. Gabelli, 61, Padova 35121, Italy.
European Laboratory for Non-Linear Spectroscopy, via N. Carrara, 1, Sesto Fiorentino (FI) 50019, Italy.
Cardiovasc Res. 2018 Jul 1;114(8):1082-1097. doi: 10.1093/cvr/cvy057.
Arrhythmogenic cardiomyopathy (AC) is an inherited heart disease characterized by life-threatening ventricular arrhythmias and fibro-fatty replacement of the myocardium. More than 60% of AC patients show pathogenic mutations in genes encoding for desmosomal proteins. By focusing our attention on the AC8 form, linked to the junctional protein desmoplakin (DSP), we present here a zebrafish model of DSP deficiency, exploited to identify early changes of cell signalling in the cardiac region.
To obtain an embryonic model of Dsp deficiency, we first confirmed the orthologous correspondence of zebrafish Dsp genes (dspa and dspb) to the human DSP counterpart. Then, we verified their cardiac expression, at embryonic and adult stages, and subsequently we targeted them by antisense morpholino strategy, confirming specific and disruptive effects on desmosomes, like those identified in AC patients. Finally, we exploited our Dsp-deficient models for an in vivo cell signalling screen, using pathway-specific reporter transgenes. Out of nine considered, three pathways (Wnt/β-catenin, TGFβ/Smad3, and Hippo/YAP-TAZ) were significantly altered, with Wnt as the most dramatically affected. Interestingly, under persistent Dsp deficiency, Wnt signalling is rescuable both by a genetic and a pharmacological approach.
Our data point to Wnt/β-catenin as the final common pathway underlying different desmosomal AC forms and support the zebrafish as a suitable model for detecting early signalling pathways involved in the pathogenesis of DSP-associated diseases, possibly responsive to pharmacological or genetic rescue.
心律失常性心肌病 (AC) 是一种遗传性心脏病，其特征是危及生命的室性心律失常和心肌纤维脂肪替代。超过 60%的 AC 患者表现出连接桥粒蛋白的编码基因的致病性突变。通过关注与连接蛋白桥粒蛋白 (DSP) 相关的 AC8 形式，我们在此展示了一种 DSP 缺陷的斑马鱼模型，用于鉴定心脏区域细胞信号的早期变化。
为了获得 Dsp 缺陷的胚胎模型，我们首先证实了斑马鱼 Dsp 基因 (dspa 和 dspb) 与人类 DSP 对应物的同源对应关系。然后，我们在胚胎和成年阶段验证了它们的心脏表达，随后通过反义 morpholino 策略靶向它们，证实了与 AC 患者中相同的桥粒特异性和破坏性影响。最后，我们利用我们的 Dsp 缺陷模型进行体内细胞信号筛选，使用途径特异性报告基因转染体。在考虑的九种途径中，有三种途径（Wnt/β-catenin、TGFβ/Smad3 和 Hippo/YAP-TAZ）发生了显著改变，其中 Wnt 受影响最严重。有趣的是，在持续的 Dsp 缺陷下，Wnt 信号可以通过遗传和药理学方法进行挽救。
我们的数据表明 Wnt/β-catenin 是不同桥粒 AC 形式的共同下游途径，并支持斑马鱼作为检测与 DSP 相关疾病发病机制相关早期信号通路的合适模型，可能对药理学或遗传挽救有反应。
