Skaletz-Rorowski A, Schmidt A, Breithardt G, Buddecke E
Institute for Arteriosclerosis Research, Division of Molecular Cardiology, Hospital of the University of Münster, Germany.
Arterioscler Thromb Vasc Biol. 1996 Aug;16(8):1063-9. doi: 10.1161/01.atv.16.8.1063.
Basic fibroblast growth factor (bFGF), a potent mitogen for arterial smooth muscle cells (SMCs), plays a pivotal role in the pathogenesis of arteriosclerosis and restenosis. Heparin in nanogram quantities may promote or even be required for binding of bFGF to its cognate receptor. Conversely, heparin in microgram doses is a strong inhibitor of arterial SMC replication in vitro and in vivo. Bovine coronary SMCs (cSMCs) express bFGF, bFGF receptor (FGF-R1), and cell membrane-integrated proteoheparan sulfate (HSPG). These three molecules are known to form a trimolecular complex that promotes signal transduction and mitogenesis. The bFGF synthesized by cSMCs is distributed to an intracellular and a pericellular compartment. Resting cultured cells retain about 80% of their bFGF intracellularly; 20% is found in the pericellular region. During proliferation, 70% to 80% of total bFGF is expressed in the pericellular compartment. Trypsinization generates soluble forms of the complex of bFGF with the ectodomains of the bFGF receptor and cell membrane-integrated HSPG in the pericellular compartment, thus allowing quantification of pericellular bFGF by a highly specific enzyme immunoassay. Standard heparin inhibits the proliferation of cSMCs by up to 80% in a concentration range between 10 and 100 micrograms/mL medium in a dose-dependent manner but increases the protein content of cSMCs compared with proliferating control cells. The heparin-induced increase in cellular protein content includes a 60% to 100% increase in the expression of pericellular bFGF, FGF-R1, and cell membrane-integrated HSPG. Thus, under heparin treatment, the heparan sulfate side chains of cell membrane-integrated HSPG incorporate more [35S]sulfate, and the proportion of [35S]heparan sulfate among total glycosaminoglycans increases from 36% to 52%. Fluorescence-activated cell sorting analysis and [3H]thymidine incorporation experiments provide evidence for multiple effects of heparin, including blocks at early and late checkpoints of the cell cycle in heparin-treated cells. These results indicate that heparin, despite its anti-proliferative potency, stimulates the expression of all components of the bFGF system even in coronary SMCs in which growth is inhibited.
碱性成纤维细胞生长因子（bFGF）是动脉平滑肌细胞（SMC）的一种强效有丝分裂原，在动脉粥样硬化和再狭窄的发病机制中起关键作用。纳克量的肝素可能促进bFGF与其同源受体的结合，甚至是其结合所必需的。相反，微克剂量的肝素在体外和体内都是动脉SMC复制的强抑制剂。牛冠状动脉平滑肌细胞（cSMC）表达bFGF、bFGF受体（FGF-R1）和细胞膜整合的蛋白聚糖硫酸酯（HSPG）。已知这三种分子形成促进信号转导和有丝分裂的三分子复合物。cSMC合成的bFGF分布于细胞内和细胞周间隙。静止培养的细胞约80%的bFGF保留在细胞内；20%存在于细胞周区域。在增殖过程中，总bFGF的70%至80%在细胞周间隙表达。胰蛋白酶消化产生bFGF与细胞周间隙中bFGF受体胞外域和细胞膜整合HSPG复合物的可溶性形式，从而可通过高度特异性的酶免疫测定法定量细胞周bFGF。标准肝素在培养基中10至100微克/毫升的浓度范围内以剂量依赖方式抑制cSMC增殖达80%，但与增殖的对照细胞相比增加了cSMC的蛋白质含量。肝素诱导的细胞蛋白质含量增加包括细胞周bFGF、FGF-R1和细胞膜整合HSPG表达增加60%至100%。因此，在肝素处理下，细胞膜整合HSPG的硫酸乙酰肝素侧链掺入更多的[35S]硫酸盐，[35S]硫酸乙酰肝素在总糖胺聚糖中的比例从36%增加到52%。荧光激活细胞分选分析和[3H]胸苷掺入实验为肝素的多种作用提供了证据，包括在肝素处理的细胞中细胞周期早期和晚期检查点的阻滞。这些结果表明，肝素尽管具有抗增殖能力，但即使在生长受到抑制的冠状动脉SMC中也能刺激bFGF系统所有成分的表达。
