SECRETION OF INSULIN-LIKE GROWTH FACTOR-I AND INSULIN-LIKE GROWTH-FACTOR BINDING-PROTEINS BY MURINE BONE-MARROW STROMAL CELLS
SECRETION OF INSULIN-LIKE GROWTH FACTOR-I AND INSULIN-LIKE GROWTH-FACTOR BINDING-PROTEINS BY MURINE BONE-MARROW STROMAL CELLS
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DOI：
10.1172/jci115327
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发表时间：
1991-08-01
影响因子：
15.9
通讯作者：
ARON, DC
中科院分区：
文献类型：
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作者：
ABBOUD, SL;BETHEL, CR;ARON, DC
胰岛素样生长因子I （IGF-I）刺激造血。我们检测骨髓基质细胞是否合成igf - 1。TC-1小鼠骨髓基质细胞分泌IGF-I的免疫反应性具有时间依赖性，并被环己亚胺抑制。在TC-1条件培养基变性条件下，凝胶过滤层析显示两个明显的IGF-I免疫反应性峰，分子量约为7.5-8.0 kD，天然IGF-I大小，>为25 kD。通过RNase保护实验和逆转录/聚合酶链反应检测IGF-I mRNA的表达。为了确定RIA鉴定的> 25-kD物种是否具有igf结合活性（人工IGF-I免疫反应性的潜在原因），对这些凝胶过滤馏分进行了木炭吸附试验。igf结合活性的峰值与明显的IGF-I免疫反应性有关，表明TC-1细胞分泌igf结合蛋白。未分级条件培养基显示出[I-125]-IGF-I特异性结合的线性剂量依赖性增加，并具有IGF-I和IGF-II >>>胰岛素的位移模式特征。条件培养基的Western配体分析显示三种IGF-I结合种约为31、38和40 kD。这些数据表明TC-1骨髓基质细胞可以合成和分泌IGF-I和igf结合蛋白，为研究其在造血中的调控作用提供了一个有用的模型系统。
Insulin-like growth factor I (IGF-I) stimulates hematopoiesis. We examined whether bone marrow stromal cells synthesize IGF-I. Secretion of IGF-I immunoreactivity by cells from TC-1 murine bone marrow stromal cells was time-dependent and inhibited by cycloheximide. Gel filtration chromatography under denaturing conditions of TC-1 conditioned medium demonstrated two major peaks of apparent IGF-I immunoreactivity with molecular weights of approximately 7.5-8.0 kD, the size of native IGF-I, and > 25 kD. Expression of IGF-I mRNA was identified by both RNase protection assay and reverse transcription/polymerase chain reaction. To determine whether the > 25-kD species identified by RIA possessed IGF-binding activity, a potential cause of artifactual IGF-I immunoreactivity, charcoal adsorption assay of these gel filtration fractions was performed. The peak of IGF-binding activity coeluted with apparent IGF-I immunoreactivity suggesting that TC-1 cells secrete IGF-binding protein(s). Unfractionated conditioned medium exhibited linear dose-dependent increase in specific binding of [I-125]-IGF-I with a pattern of displacement (IGF-I and IGF-II >>> insulin) characteristic of IGF-binding proteins. Western ligand analysis of conditioned medium showed three IGF-I binding species of approximately 31, 38, and 40 kD. These data indicate that TC-1 bone marrow stromal cells synthesize and secrete IGF-I and IGF-binding proteins and constitute a useful model system to study their regulation and role in hematopoiesis.