Natriuretic peptide receptor-B in adult rat ventricle is predominantly confined to the nonmyocyte population
Natriuretic peptide receptor-B in adult rat ventricle is predominantly confined to the nonmyocyte population
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DOI：
10.1152/ajpheart.00988.2001
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发表时间：
2002-06-01
影响因子：
4.8
通讯作者：
Palfrey, HC
中科院分区：
文献类型：
--
作者：
Doyle, DD;Upshaw-Earley, J;Palfrey, HC
我们用多种技术研究了C型利钠肽(CNP)鸟苷环化酶B(GC-B)受体在成年大鼠心脏中的细胞定位和相对浓度。在脑室冰冻切片中，抗受体抗体将血管系统和间质细胞染色到心肌细胞，而不是肌细胞本身。同样的抗体在非心肌细胞蛋白提取物的免疫印迹中检测到GC-B，但在心肌细胞免疫印迹中检测到，并在培养的心脏成纤维细胞提取物中识别相同的蛋白质，但不识别A7r5大鼠的平滑肌细胞。在功能分析中，在培养的心脏成纤维细胞中，CNP诱导的每毫克细胞蛋白中cGMP的积聚比A7r5平滑肌细胞高一个数量级，比新鲜分离的心肌细胞高两个数量级。磷酸二酯酶(PDEs)对cGMP积累的调节是细胞特异性的，通过拮抗剂药理图谱确定，PDE1在成纤维细胞中，PDE2在A7r5细胞中，PDE3在心肌细胞中，提示心肌细胞对CNP的显著但低水平的cGMP反应不是由于非心肌细胞的污染。心脏来源的成纤维细胞对CNP的受体反应性、cGMP水平和增殖相关的丝裂原激活的信号转导途径之间没有交互关系。虽然以前的报道表明CNP对新生大鼠心肌细胞有显著影响，但我们的结果表明，成纤维细胞可能是成年大鼠心脏中反应最快的细胞类型(cGMP产生)。
We assessed the cellular localization and relative concentration of the C-type natriuretic peptide (CNP) guanylate cyclase-B (GC-B) receptor in the adult rat heart ventricle by several techniques. In frozen sections of the ventricle, anti-receptor antibody stained the vasculature and cells interstitial to myocytes, but not the myocytes themselves. The same antibody detected GC-B in immunoblots of protein extracts of nonmyocytes, but not myocytes and recognized an equivalent protein in extracts of cultured cardiac fibroblasts, but not A7r5 rat smooth muscle cells. In functional assays, CNP-induced cGMP accumulation per milligram cell protein was an order of magnitude greater in cultured cardiac fibroblasts than in A7r5 smooth muscle cells and two orders of magnitude greater than in freshly isolated cardiac myocytes. Modulation of cGMP accumulation by phosphodiesterases (PDEs) was cell specific as determined by antagonist pharmacological profiles, PDE1 in fibroblasts, PDE2 in A7r5 cells, and PDE3 in myocytes, suggesting that significant but low-level cGMP response to CNP measured in heart myocytes is not due to nonmyocyte contamination. Fibroblasts of cardiac origin do not show an interactive relationship between receptor responsiveness to CNP, cGMP levels, and proliferation-related mitogen-activated signal transduction pathways. Whereas previous reports suggest CNP exerts significant effects in neonatal rat cardiomyocytes, our results suggest that fibroblasts are likely the most responsive cell type (cGMP production) in the adult rat heart.