From the Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada (M.C.B., R.L.E.A., Y.-Q.Z., L.-l.C., Z.M., A.Y.-L.L., R.K.K.T., H.Z., S.P.H., C.A.S.); Institute of Biomaterials and Biomedical Engineering (M.C.B., K.W., R.L.E.A., A.Y.-L.L., R.K.K.T., C.A.S.), Department of Physiology (H.Z., S.P.H.), and Department of Mechanical and Industrial Engineering (L.-l.C., Z.M., C.A.S.), University of Toronto, Ontario, Canada; and Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada (Y.-Q.Z., R.M.H.).
Circ Res. 2018 Feb 2;122(3):405-416. doi: 10.1161/CIRCRESAHA.117.311194. Epub 2017 Dec 22.
Aortic valve disease is a cell-mediated process without effective pharmacotherapy. CNP (C-type natriuretic peptide) inhibits myofibrogenesis and osteogenesis of cultured valve interstitial cells and is downregulated in stenotic aortic valves. However, it is unknown whether CNP signaling regulates aortic valve health in vivo.
The aim of this study is to determine whether a deficient CNP signaling axis in mice causes accelerated progression of aortic valve disease.
In cultured porcine valve interstitial cells, CNP inhibited pathological differentiation via the guanylate cyclase NPR2 (natriuretic peptide receptor 2) and not the G-protein-coupled clearance receptor NPR3 (natriuretic peptide receptor 3). We used and ; mice and wild-type littermate controls to examine the valvular effects of deficient CNP/NPR2 signaling in vivo, in the context of both moderate and advanced aortic valve disease. Myofibrogenesis in cultured fibroblasts was insensitive to CNP treatment, whereas aged and ;-/- mice developed cardiac dysfunction and ventricular fibrosis. Aortic valve function was significantly impaired in and ; mice versus wild-type littermates, with increased valve thickening, myofibrogenesis, osteogenesis, proteoglycan synthesis, collagen accumulation, and calcification. 9.4% of mice heterozygous for had congenital bicuspid aortic valves, with worse aortic valve function, fibrosis, and calcification than those with typical tricuspid aortic valves or all wild-type littermate controls. Moreover, cGK (cGMP-dependent protein kinase) activity was downregulated in valves, and CNP triggered synthesis of cGMP and activation of cGK1 (cGMP-dependent protein kinase 1) in cultured porcine valve interstitial cells. Finally, aged ; mice developed dilatation of the ascending aortic, with greater aneurysmal progression in mice with bicuspid aortic valves than those with tricuspid valves.
Our data establish CNP/NPR2 signaling as a novel regulator of aortic valve development and disease and elucidate the therapeutic potential of targeting this pathway to arrest disease progression.
主动脉瓣疾病是一种细胞介导的过程，目前尚无有效的药物治疗方法。CNP（C 型利钠肽）可抑制培养的瓣膜间质细胞的成肌纤维和成骨作用，并在狭窄的主动脉瓣中下调。然而，尚不清楚 CNP 信号是否调节体内主动脉瓣的健康。
本研究旨在确定小鼠中 CNP 信号轴的缺陷是否会导致主动脉瓣疾病的进展加速。
在培养的猪瓣膜间质细胞中，CNP 通过鸟苷酸环化酶 NPR2（利钠肽受体 2）而不是 G 蛋白偶联清除受体 NPR3（利钠肽受体 3）抑制病理性分化。我们使用 和 ; 小鼠和野生型同窝对照来研究体内 CNP/NPR2 信号缺陷对中度和重度主动脉瓣疾病的影响。培养的 成纤维细胞中的成肌纤维形成对 CNP 处理不敏感，而衰老的 和 ;-/- 小鼠则发展为心脏功能障碍和心室纤维化。与野生型同窝对照相比， 和 ; 小鼠的主动脉瓣功能明显受损，表现为瓣膜增厚、成肌纤维形成、成骨形成、蛋白聚糖合成、胶原积累和钙化。杂合子 小鼠中有 9.4%发生先天性二叶式主动脉瓣，其主动脉瓣功能、纤维化和钙化均较典型三叶式主动脉瓣或所有野生型同窝对照差。此外， 瓣膜中的 cGK（环鸟苷酸依赖性蛋白激酶）活性下调，CNP 可触发培养的猪瓣膜间质细胞中环鸟苷酸的合成和 cGK1（环鸟苷酸依赖性蛋白激酶 1）的激活。最后，老年 ; 小鼠出现升主动脉扩张，而二叶式主动脉瓣的 ; 小鼠比三叶式主动脉瓣的 ; 小鼠的动脉瘤进展更大。
我们的数据确立了 CNP/NPR2 信号作为主动脉瓣发育和疾病的新调节因子，并阐明了靶向该途径以阻止疾病进展的治疗潜力。
