Heparan sulfate mediates bFGF transport through basement membrane by diffusion with rapid reversible binding
Heparan sulfate mediates bFGF transport through basement membrane by diffusion with rapid reversible binding
复制标题
DOI：
10.1074/jbc.274.8.5236
复制
发表时间：
1999-02-19
影响因子：
4.8
通讯作者：
Nugent, MA
中科院分区：
文献类型：
--
作者：
Dowd, CJ;Cooney, CL;Nugent, MA
碱性成纤维细胞生长因子（bFGF）是一种具有广泛靶细胞的多能细胞因子。硫酸乙酰肝素结合bFGF，并且已经证明这种相互作用保护bFGF免受物理变性和蛋白酶降解。基底膜中高浓度的硫酸乙酰肝素暗示这些基质是bFGF在体内的储存位点。然而，基底膜调节bFGF储存和释放的机制尚不清楚。为了深入了解这些机制，我们已经开发了细胞外生长因子通过基底膜转运的实验和数学模型。将从牛角膜分离的完整后弹力膜安装在定制的扩散池内，并在各种条件下测量生长因子转运，所述条件将扩散过程与硫酸乙酰肝素结合现象解耦。用bFGF和白细胞介素1 β进行转运实验。此外，在使用高离子强度缓冲液和含有硫酸鱼精蛋白的缓冲液的扩散研究中，bFGF-硫酸乙酰肝素结合被破坏。当硫酸乙酰肝素结合被抑制时，bFGF的转运显著增强。该过程被建模为具有快速可逆结合的扩散问题。将实验参数纳入数学模型并运行独立模拟，结果表明数学模型准确预测了实验数据。因此，这项研究表明，基底膜的功能作为生长因子运输的动态调节器，允许快速响应不断变化的环境条件。控制bFGF通过基底膜运输的基本原则，已确定在这里可能有应用程序在了解生长因子分布是如何调节整个生物体在发展过程中，并在成人状态。
Basic fibroblast growth factor (bFGF) is a pluripotent cytokine with a wide range of target cells. Heparan sulfate binds bFGF, and this interaction has been demonstrated to protect bFGF against physical denaturation and protease degradation. The high concentrations of heparan sulfate in basement membranes have implicated these matrices as storage sites for bFGF in vivo. However, the mechanisms by which basement membranes modulate bFGF storage and release is unknown. To gain insight into these mechanisms, we have developed experimental and mathematical models of extracellular growth factor transport through basement membrane. Intact Descemet's membranes isolated from bovine corneas were mounted within customized diffusion cells and growth factor transport was measured under a variety of conditions that decoupled the diffusion process from the heparan sulfate binding phenomenon. Transport experiments were conducted with bFGF and interleukin 1 beta. In addition, bFGF-heparan sulfate binding was disrupted in diffusion studies with high ionic strength buffer and buffers containing protamine sulfate. Transport of bFGF was enhanced dramatically when heparan sulfate binding was inhibited. This process was modeled as a problem of diffusion with fast reversible binding. Experimental parameters were incorporated into a mathematical model and independent simulations were run that showed that the experimental data were accurately predicted by the mathematical model. Thus, this study indicated that basement membranes function as dynamic regulators of growth factor transport, allowing for rapid response to changing environmental conditions. The fundamental principles controlling bFGF transport through basement membrane that have been identified here might have applications in understanding how growth factor distribution is regulated throughout an organism during development and in the adult state.