CULTURED ENDOTHELIAL-CELLS PRODUCE A PLATELET-DERIVED GROWTH FACTOR-LIKE PROTEIN
CULTURED ENDOTHELIAL-CELLS PRODUCE A PLATELET-DERIVED GROWTH FACTOR-LIKE PROTEIN
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DOI：
10.1073/pnas.80.7.1919
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发表时间：
1983-01-01
期刊：
影响因子：
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通讯作者：
BOWENPOPE, DF
中科院分区：
文献类型：
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作者：
DICORLETO, PE;BOWENPOPE, DF
血小板衍生生长因子（PDGF）与牛主动脉平滑肌细胞和[瑞士白化病小鼠成纤维细胞] 3 T3细胞表面的高亲和力受体特异性结合。来自培养的牛主动脉内皮细胞（EC）的条件培养基在4 ℃下以剂量依赖性方式阻止PDGF与这些受体结合。C. 125 I标记的PDGF被条件培养基取代，三氯乙酸溶解度没有增加，与新鲜细胞的结合能力也没有降低。通过硫酸铵沉淀性和对胰蛋白酶的敏感性鉴定竞争活性为蛋白质。在猪主动脉EC和人脐静脉EC的无血清条件培养基中也发现了竞争蛋白，但在牛主动脉平滑肌细胞、人新生儿包皮成纤维细胞或产生白细胞介素的胸腺瘤细胞lime EL-4 [小鼠T细胞淋巴瘤]的培养基中未发现竞争蛋白。竞争蛋白质，如PDGF，对特异性4. C. 125 I标记的胰岛素与3 T3细胞或125 I标记的表皮生长因子与人表皮样[外阴癌] A431细胞的结合。PDGF与平滑肌细胞结合的饱和曲线表明，125 I标记的PDGF与其受体的半最大结合浓度不受竞争对手的影响;然而，可用的受体位点或最大结合水平的表观数量大大减少。由培养的人脐静脉EC产生的竞争活性被抗纯人PDGF的抗血清完全抑制，而相同的PDGF抗血清仅部分抑制条件培养基的促有丝分裂活性。此外，7-对于125 I标记的PDGF结合的半数最大抑制，需要比对于DNA合成的半数最大刺激所需的多1倍的粗内皮衍生生长因子。EC显然分泌PDGF样蛋白，其在生物化学上不同于大多数EC衍生的促有丝分裂活性。
The platelet-derived growth factor (PDGF) binds specifically to high-affinity receptors on the surface of bovine aortic smooth muscle cells and [Swiss albino mouse fibroblast] 3T3 cells. Conditioned medium from cultured bovine aortic endothelial cells (EC) prevents PDGF binding to these receptors in a dose-dependent manner at 4.degree. C. The 125I-labeled PDGF that is displaced by the conditioned medium shows no increase in trichloroacetic acid solubility or decrease in binding capability to fresh cells. The competitor activity was identified as a protein by ammonium sulfate precipitability and sensitivity to trypsin. The competitor protein also is found in the serum-free conditioned media from porcine aortic EC and human umbilical vein EC, but not in media from bovine aortic smooth muscle cells, human neonatal foreskin fibroblasts, or the interleukin-producing thyoma cell lime EL-4 [mouse T-cell lymphoma]. The competitor protein, like PDGF, has no effect on the specific 4.degree. C binding of either 125I-labeled insulin to 3T3 cells or of 125I-labeled epidermal growth factor to human epidermoid [vulvar carcinoma] A431 cells. Saturation curves of PDGF binding to smooth muscle cells which had been preincubated in the presence and absence of competitor indicate that the concentration for half-maximal binding of 125I-labeled PDGF to its receptor is unchanged by the competitor; however, the apparent number of available receptor sites or maximal level of binding is greatly diminished. The competitor activity produced by cultured human umbilical vein EC is completely inhibited by antiserum against pure human PDGF, whereas the same PDGF antiserum only partially inhibits the mitogenic activity of the conditioned media. In addition .apprxeq. 7-fold more crude endothelium-derived growth factor is required for half-maximal inhibition of 125I-labeled PDGF binding as is required for half-maximal stimulation of DNA synthesis. EC apparently secretes a PDGF-like protein that is biochemically distinct from the majority of EC-derived mitogenic activity.