Human skin fibroblasts as a model of growth hormone (GH) action in GH receptor-positive Laron's syndrome
Human skin fibroblasts as a model of growth hormone (GH) action in GH receptor-positive Laron's syndrome
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DOI：
10.1210/en.138.1.55
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发表时间：
1997-01-01
期刊：
影响因子：
4.8
通讯作者：
Clayton, PE
中科院分区：
文献类型：
--
作者：
Freeth, JS;Ayling, RM;Clayton, PE
先天性GH不敏感（Laron综合征，LS）通常与GH受体（GHR）功能障碍相关，导致对GH完全不敏感和血清GH结合蛋白（GHBP）缺失。然而，一部分LS儿童的GHBP水平正常。我们从两个家族中发现了4名患有这种疾病的女孩（身高评分为-3.4至-6.8），并对1）其GHR基因和2）培养的皮肤成纤维细胞中的GH反应进行了研究，以确定其GH不敏感性的病因。在另一个家庭中，受影响的兄弟姐妹，一个未受影响的兄弟，和父亲是杂合子的外显子6（D152 H）内的点突变。此外，使用内含子9单倍型来确定与GHR基因的连锁意味着后一个家族的两个受影响的鳃中遗传了不同的母体GHR等位基因。这是不太可能的，因此，D152 H突变单独可以解释LS phenotype.End点GH行动[DNA合成，胰岛素样生长因子结合蛋白-3（IGFBP-3）信使RNA（mRNA）和肽的生产]在皮肤成纤维细胞培养建立从三个LS科目和四个正常儿童进行了检查。正常成纤维细胞对10-1000 ng/ml GH呈剂量依赖性掺入[H-3]胸苷（1000 ng/ml时增加，77 +/-19%），LS成纤维细胞对高于基础水平的GH无显著反应（P < 0.01）。在正常成纤维细胞中，IGFBP-3的mRNA和肽增加最大，在48小时响应于200 ng/ml的GH，通过核糖核酸酶保护试验，蛋白质配体印迹，和RIA测定。这些研究表明：1）培养的人皮肤成纤维细胞可用于确定GH作用的终点; 2）来自LS儿童的成纤维细胞培养物对GH无反应或反应降低;这些儿童的GH不敏感性似乎并不完全由GHR突变引起，而可能是由于GHR信号传导功能障碍。这类患者可能被证明对阐明GH信号传导中的关键事件特别重要。
Congenital GH insensitivity (Laron's syndrome, LS) is often associated with a dysfunctional GH receptor (GHR) causing complete insensitivity to GH and absent serum GH-binding protein (GHBP). However, a proportion of children with LS have normal GHBP levels. We have identified four girls fr om two families with this condition (height so score, -3.4 to -6.8) and undertaken studies on 1) their GHR genes and 2) their GH responses in cultured skin fibroblasts to define the etiology of their GH insensitivities.No GHR gene mutations were identified in one family. In the other family, the affected siblings, an unaffected brother, and the father were heterozygous for a point mutation within exon 6 (D152H). In addition, use of intron 9 haplotypes to determine linkage to the GHR gene implied inheritance of different maternal GHR alleles in the two affected gills of the latter family. It is unlikely, therefore, that the D152H mutation alone could account for the LS phenotype.End points of GH action [DNA synthesis, insulin-like growth factor-binding protein-3 (IGFBP-3) messenger RNA (mRNA) and peptide production] in skin fibroblast cultures established from three of the LS subjects and four normal children were examined. Whereas normal Fibroblasts incorporated [H-3]thymidine dose dependently in response to 10-1000 ng/ml GH (increment at 1000 ng/ml, 77 +/- 19%), LS fibroblasts failed to respond significantly above basal levels (P < 0.01). In normal fibroblasts, IGFBP-3 mRNA and peptide increased maximally at 48 h in response to 200 ng/ml GH, as determined by ribonuclease protection assay, Western ligand blotting, and RIA. In comparison, LS fibroblasts produced significantly less IGFBP-3 peptide than normal fibroblasts in response to GH, whereas IGFBP-3 mRNA failed to increase above basal levels.These studies have shown that 1) cultured human skin fibroblasts can be used to define the end points of GH action; 2) fibroblast cultures from the LS children show absent or reduced responses to GH; and 31 GH insensitivity in these children does not appear to be caused exclusively by GHR mutations, but is probably due to dysfunctional GHR signalling. Such patients may prove particularly important to elucidation of the key events in GH signaling.