Dhaunsi G S, Hassid A
Department of Physiology and Biophysics, University of Tennessee, Memphis 38163, USA.
Cardiovasc Res. 1996 Jan;31(1):37-47.
The objective of the current study was to determine whether atrial natriuretic peptides enhance the mitogenic effect of FGF-2, based on a previous study showing that NO enhances the mitogenic effect of FGF-2.
Primary rat aortic smooth muscle cells were used for all experiments. Mitogenic activity was determined by (3H)thymidine incorporation and cell counting. Cyclic GMP was measured by radioimmunoassay. Messenger RNA was measured by Northern blotting. FGFR-1 receptor protein was measured by Western blotting.
ANP and CNP had no consistent mitogenic effect of their own but they both enhanced FGF-2-induced DNA synthesis and/or cell proliferation by 2-3 fold. ANP enhanced the increase of c-fos mRNA induced by FGF-2. ANP, alone or in combination with FGF-2, had no effect on FGF receptor protein levels. HS-142-1, a specific antagonist of guanylyl cyclase-linked A- or B-type ANP receptors, inhibited the co-mitogenic effect of ANP. Exogenous cGMP was also co-mitogenic, whereas two peptides that bind selectively to the ANF C-receptor, cANF and des[Cys105, Cys121]rANF104-126, had no mitogenic or co-mitogenic effect. The co-mitogenic effect of ANP gradually disappeared as the subculture number of the cells was increased, indicating that it was selective for primary cells. ANP enhanced the mitogenic response of primary aortic smooth muscle cells to EGF whereas that to IGF-1 and PDGF was either not increased, or increased modestly.
ANP enhances the mitogenic effect of FGF-2, via a mechanism that may involve elevation of immediate early gene expression but not enhancement of FGF receptor protein levels. We speculate that ANP and CNP released from macrophages and endothelial cells could enhance the mitogenic effect of FGF-2 or EGF in vivo.
基于之前一项显示一氧化氮增强成纤维细胞生长因子-2（FGF-2）促有丝分裂作用的研究，本研究的目的是确定心房利钠肽是否增强FGF-2的促有丝分裂作用。
所有实验均使用原代大鼠主动脉平滑肌细胞。通过（3H）胸腺嘧啶核苷掺入和细胞计数来测定促有丝分裂活性。通过放射免疫测定法测量环磷酸鸟苷（cGMP）。通过Northern印迹法测量信使核糖核酸（mRNA）。通过蛋白质印迹法测量FGFR-1受体蛋白。
心房利钠肽（ANP）和C型利钠肽（CNP）自身没有一致的促有丝分裂作用，但它们都使FGF-2诱导的DNA合成和/或细胞增殖增强了2至3倍。ANP增强了FGF-2诱导的c-fos mRNA的增加。ANP单独或与FGF-2联合使用时，对FGF受体蛋白水平没有影响。HS-142-1，一种鸟苷酸环化酶连接的A型或B型ANP受体的特异性拮抗剂，抑制了ANP的协同促有丝分裂作用。外源性cGMP也具有协同促有丝分裂作用，而两种选择性结合心房钠尿肽C受体的肽，cANF和des[Cys105，Cys121]rANF104-126，没有促有丝分裂或协同促有丝分裂作用。随着细胞传代次数增加，ANP的协同促有丝分裂作用逐渐消失，表明它对原代细胞具有选择性。ANP增强了原代主动脉平滑肌细胞对表皮生长因子（EGF）的促有丝分裂反应，而对胰岛素样生长因子-1（IGF-1）和血小板衍生生长因子（PDGF）的反应要么没有增加，要么仅适度增加。
ANP通过一种可能涉及提高即刻早期基因表达但不增强FGF受体蛋白水平的机制增强FGF-2的促有丝分裂作用。我们推测巨噬细胞和内皮细胞释放的ANP和CNP可能在体内增强FGF-2或EGF的促有丝分裂作用。
