Komatsu Y, Itoh H, Suga S, Igaki T, Ogawa Y, Kishimoto I, Nakagawa O, Yoshimasa T, Nakao K
Department of Medicine and Clinical Sciences, Kyoto University Graduate School of Medicine, Japan.
J Hypertens. 1996 May;14(5):585-92. doi: 10.1097/00004872-199605000-00007.
To clarify the significance of C-type natriuretic peptide in the interaction between endothelial cells and vascular smooth muscle cells by investigating the endothelial production of C-type natriuretic peptide and the clearance mechanism of C-type natriuretic peptide using the endothelial cells-smooth muscle cells co-culture system.
Secretion of C-type natriuretic peptide in the direct co-culture of endothelial cells with smooth muscle cells elicited as much as a 60-fold increase compared with endothelial cells alone. The accumulation of intracellular cyclic GMP in the co-culture was consequently increased and the elevation of cyclic GMP level in the co-culture was abolished by the anti-C-type natriuretic peptide monoclonal antibody. The elevated cyclic GMP production in the co-culture was abolished by the anti-transforming growth factor-beta neutralizing antibody. Candoxatrilat (10(-6)-10(-4) mol/l), a neutral endopeptidase inhibitor, dose-dependently increased the concentrations of C-type natriuretic peptide in the culture medium with endothelial cells alone, but not in the endothelial cells-smooth muscle cells co-culture. The transcript of neutral endopeptidase messenger RNA was detected in endothelial cells but not in smooth muscle cells by reverse transcriptase polymerase chain reaction. Treatment with C-atrial natriuretic factor4-23 (10(-9)-10(-6) mol/l), the specific ligand for the clearance receptor of the natriuretic peptides, resulted in dose-dependent augmentation of C-type natriuretic peptide concentration and concomitant intracellular cyclic GMP production in the endothelial cells-smooth muscle cells co-culture but not in endothelial cells alone.
The present study demonstrated that direct interaction between endothelial cells and smooth muscle cells augments C-type natriuretic peptide secretion from endothelial cells through transforming growth factor-beta activation, and revealed that the enzymatic degradation is responsible for the steady state level of C-type natriuretic peptide in endothelial cells alone and that the receptor-mediated clearance mainly determines the augmented level of C-type natriuretic peptide in the interaction between endothelial cells and smooth muscle cells. The results taken together raise the possibility that endothelial C-type natriuretic peptide might play a role in regulation of vascular tone and remodelling.
通过使用内皮细胞 - 平滑肌细胞共培养系统研究C型利钠肽的内皮生成及清除机制，阐明C型利钠肽在内皮细胞与血管平滑肌细胞相互作用中的意义。
与单独培养的内皮细胞相比，内皮细胞与平滑肌细胞直接共培养时C型利钠肽的分泌增加了多达60倍。共培养中细胞内环磷酸鸟苷（cGMP）的积累因此增加，且抗C型利钠肽单克隆抗体消除了共培养中环磷酸鸟苷水平的升高。抗转化生长因子 - β中和抗体消除了共培养中环磷酸鸟苷产生的升高。坎多沙坦酯（10⁻⁶ - 10⁻⁴ mol/l），一种中性内肽酶抑制剂，可剂量依赖性增加单独培养内皮细胞时培养基中C型利钠肽的浓度，但在内皮细胞 - 平滑肌细胞共培养中无此作用。通过逆转录聚合酶链反应在内皮细胞中检测到中性内肽酶信使核糖核酸的转录本，而在平滑肌细胞中未检测到。用利钠肽清除受体的特异性配体C - 心房利钠因子4 - 23（10⁻⁹ - 10⁻⁶ mol/l）处理，导致内皮细胞 - 平滑肌细胞共培养中C型利钠肽浓度剂量依赖性增加以及细胞内cGMP产生增加，但单独培养的内皮细胞中无此现象。
本研究表明内皮细胞与平滑肌细胞之间的直接相互作用通过转化生长因子 - β激活增强了内皮细胞C型利钠肽的分泌，并揭示酶促降解决定了单独培养内皮细胞中C型利钠肽的稳态水平，而受体介导的清除主要决定了内皮细胞与平滑肌细胞相互作用中C型利钠肽的增加水平。综合这些结果增加了内皮C型利钠肽可能在血管张力调节和重塑中发挥作用的可能性。
