Cardiovascular Developmental Biology Department, Centro Nacional de Investigaciones Cardiovasculares, Instituto de Salud Carlos III, 28029 Madrid, Spain.
Arterioscler Thromb Vasc Biol. 2011 Jul;31(7):1580-8. doi: 10.1161/ATVBAHA.111.227561. Epub 2011 Apr 14.
Calcific aortic valve disease is similar to atherosclerosis in that both diseases result from chronic inflammation and endothelial dysfunction. Heterozygous NOTCH1 mutations have been associated to calcific aortic disease and a bicuspid aortic valve. We investigated whether mice with genetic inactivation of the Notch signaling pathway are prone to develop valve disease when exposed to a predisposing diet.
Using Doppler echocardiography, histology, immunohistochemistry, quantitative gene expression analysis, and cell culture assays, we examined the effect of a hypercholesterolemic diet supplemented with vitamin D on mice heterozygous for null mutations in the Notch1 receptor or the effector transcription factor gene RBPJk. After 16 weeks on the hyperlipidemic diet, calcific aortic disease was detected in heterozygous RBPJk mice. Analysis of valve leaflets revealed macrophage infiltration, enhanced collagen deposition, proosteogenic protein expression, and calcification. Heterozygous null Notch1 mice displayed milder histopathologic changes and did not develop any significant hemodynamic disturbance. Valvular disease correlated with reduced expression of the Notch target gene Hey1 in valves of RBPJk heterozygous mice fed the hyperlipidemic diet. Consistent with the in vivo data, Notch signaling inhibition in porcine valve interstitial cells led to downregulation of HEY1 transcription, activation of osteogenic markers, and increased calcified nodule formation.
We show that Notch signaling disruption via RBPJk heterozygous inactivation results in aortic valve disease. Notch1 heterozygous mice do not show functional impairment, suggesting that additional Notch receptors may be involved in aortic valve homeostasis and disease. Our data establish a genetic mouse model of calcific aortic valve disease and may help to identify a patient population with reduced valvular NOTCH signaling at risk for developing this disease.
钙化性主动脉瓣疾病与动脉粥样硬化相似，两者均由慢性炎症和内皮功能障碍引起。杂合性 NOTCH1 突变与钙化性主动脉疾病和二叶式主动脉瓣有关。我们研究了 Notch 信号通路基因失活的小鼠在暴露于易感饮食时是否容易发生瓣膜疾病。
使用多普勒超声心动图、组织学、免疫组织化学、定量基因表达分析和细胞培养实验，我们研究了高胆固醇血症饮食补充维生素 D 对 Notch1 受体或效应转录因子基因 RBPJk 杂合缺失突变的小鼠的影响。在高脂血症饮食 16 周后，在杂合 RBPJk 小鼠中发现了钙化性主动脉疾病。对瓣膜叶的分析显示巨噬细胞浸润、胶原沉积增强、前成骨蛋白表达和钙化。杂合性 Notch1 缺失突变小鼠表现出较轻的组织病理学变化，没有任何明显的血液动力学障碍。瓣膜疾病与 RBPJk 杂合子高脂饮食喂养的小鼠瓣膜中 Notch 靶基因 Hey1 的表达减少相关。与体内数据一致，猪瓣膜间质细胞 Notch 信号抑制导致 HEY1 转录下调、成骨标志物激活和钙化结节形成增加。
我们表明，通过 RBPJk 杂合失活破坏 Notch 信号导致主动脉瓣疾病。Notch1 杂合子小鼠没有表现出功能障碍，表明其他 Notch 受体可能参与主动脉瓣的稳态和疾病。我们的数据建立了钙化性主动脉瓣疾病的遗传小鼠模型，可能有助于确定具有降低的瓣膜 NOTCH 信号的患者群体，其发生这种疾病的风险降低。
