C-type natriuretic peptide moderates titin-based cardiomyocyte stiffness
C-type natriuretic peptide moderates titin-based cardiomyocyte stiffness
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DOI：
10.1172/jci.insight.139910
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发表时间：
2020-11-19
期刊：
影响因子：
8
通讯作者：
Kuhn, Michaela
中科院分区：
文献类型：
--
作者：
Michel, Konstanze;Herwig, Melissa;Kuhn, Michaela
心力衰竭常伴有肌联蛋白依赖性心肌僵硬。肌联蛋白被cGMP依赖性蛋白激酶I（PKGI）磷酸化增加心肌细胞扩张性。刺激PKGI介导的肌联蛋白磷酸化的上游途径尚不清楚。我们研究了C型利钠肽（CNP）是否通过其鸟苷酸环化酶-B（GC-B）受体和cGMP/PKGI信号转导调节基于肌联蛋白的心室顺应性。为了剖析GC-B介导的内源性CNP在心肌细胞中的作用，我们产生了具有心肌细胞限制性GC-B缺失的小鼠（CM GC-B-KO小鼠）。研究了在基线和通过横向主动脉缩窄（TAC）诱导的后负荷增加后对心脏形态和功能、肌细胞被动张力、肌联蛋白亚型表达和磷酸化的影响。压力超负荷增加左心室内皮细胞CNP表达，3天后出现早期高峰。同时，肌联蛋白在丝氨酸（4080）（PKGI磷酸化位点）的磷酸化增强。值得注意的是，在CM GC-B-KO小鼠中，这种肌联蛋白应答被消除。TAC诱导的肥大和纤维化在基因型之间没有差异。然而，KO小鼠表现出轻度收缩和舒张功能障碍以及肌细胞僵硬，这在对照同窝仔中未观察到。在体外，重组PKGI挽救了降低的肌联蛋白-丝氨酸（4080）磷酸化，并恢复GC-B缺陷心肌细胞的被动僵硬。CNP诱导的GC-B/cGMP/PKGI信号传导在心肌细胞中的激活提供了一个保护性调节回路，防止在压力超负荷的早期阶段基于肌联蛋白的心肌细胞硬化。
Heart failure is often accompanied by titin-dependent myocardial stiffness. Phosphorylation of titin by cGMP-dependent protein kinase I (PKGI) increases cardiomyocyte distensibility. The upstream pathways stimulating PKGI-mediated titin phosphorylation are unclear. We studied whether C-type natriuretic peptide (CNP), via its guanylyl cyclase-B (GC-B) receptor and cGMP/PKGI signaling, modulates titin-based ventricular compliance. To dissect GC-B-mediated effects of endogenous CNP in cardiomyocytes, we generated mice with cardiomyocyte-restricted GC-B deletion (CM GC-B-KO mice). The impact on heart morphology and function, myocyte passive tension, and titin isoform expression and phosphorylation was studied at baseline and after increased afterload induced by transverse aortic constriction (TAC). Pressure overload increased left ventricular endothelial CNP expression, with an early peak after 3 days. Concomitantly, titin phosphorylation at Ser(4080), the site phosphorylated by PKGI, was augmented. Notably, in CM GC-B-KO mice this titin response was abolished. TAC-induced hypertrophy and fibrosis were not different between genotypes. However, the KO mice presented mild systolic and diastolic dysfunction together with myocyte stiffness, which were not observed in control littermates. In vitro, recombinant PKGI rescued reduced titin-Ser(4080) phosphorylation and reverted passive stiffness of GC-B-deficient cardiomyocytes. CNP-induced activation of GC-B/cGMP/PKGI signaling in cardiomyocytes provides a protecting regulatory circuit preventing titin-based myocyte stiffening during early phases of pressure overload.