Impaired stimulation of 25-hydroxyvitamin D-24-hydroxylase in fibroblasts from a patient with vitamin D-dependent rickets, type II. A form of receptor-positive resistance to 1,25-dihydroxyvitamin D3.
Impaired stimulation of 25-hydroxyvitamin D-24-hydroxylase in fibroblasts from a patient with vitamin D-dependent rickets, type II. A form of receptor-positive resistance to 1,25-dihydroxyvitamin D3.
复制标题
维生素 D 依赖性佝偻病 II 型患者的成纤维细胞中 25-羟基维生素 D-24-羟化酶的刺激受损。
DOI：
10.1172/jci111074
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Zerwekh,JE
中科院分区：
文献类型：
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作者：
Griffin,JE;Zerwekh,JE
我们描述了1，25-二羟维生素D3 [1，25-（OH）2D 3]在培养的皮肤成纤维细胞中作用的分子缺陷的研究，该细胞来自先前报道的维生素D依赖性佝偻病II型患者。[3 H] 1，25-（OH）2D 3在成纤维细胞胞质溶胶中的结合正常，Bmax（高亲和力结合量）为26 fmol/mg蛋白，半最大饱和度为0.2 nM。在患者成纤维细胞中，全细胞摄取后[3 H] 1，25-（OH）2D 3的核结合为1.5 fmol/μ g DNA，而在5种对照菌株中为0.5-2.9 fmol/μ g DNA。[3 H] 1，25-（OH）2D 3-受体复合物在蔗糖密度梯度上的大小为3.8 S，与正常细胞相同。因此，该患者似乎对1，25-（OH）2D 3具有受体阳性形式的抗性。为了证明成纤维细胞对1，25-（OH）2D 3的抗性，我们开发了一种检测正常皮肤成纤维细胞中1，25-（OH）2D 3作用的方法。用1，25-（OH）2D 3处理正常细胞单层后，25-羟基-维生素D-24-羟化酶（24-羟化酶）活性增加了20倍以上。用1，25-（OH）2D 3处理10个对照细胞株8小时，在细胞超声处理物中从25-羟基维生素D3形成24，25-二羟基维生素D3从小于0.02 pmol/min增加到0.11-0.27 pmol/min/mg蛋白。当用1，25-（OH）2D 3以类似的方式处理维生素D依赖性佝偻病II型患者的细胞时，最大24-羟化酶活性仅为0.02 pmol/min/mg蛋白质，不到正常下限的五分之一。24-患者父母的成纤维细胞中羟化酶活性在1，25-（OH）2D 3治疗后正常增加。我们的结论是，在正常受体结合的存在下，24-羟化酶的诱导受损是受体后抵抗1，25-（OH）2D 3作用的证据。
We describe studies of the molecular defect in 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] action in cultured skin fibroblasts from a patient previously reported to have vitamin D-dependent rickets, type II. Binding of [3H]1,25-(OH)2D3 in fibroblast cytosol was normal with a Bmax (amount of high affinity binding) of 26 fmol/mg protein and a half-maximal saturation of 0.2 nM. Nuclear binding of [3H]1,25-(OH)2D3 following whole cell uptake was 1.5 fmol/micrograms DNA in patient fibroblasts compared with a range of 0.5-2.9 fmol/micrograms DNA in five control strains. The size of the [3H]1,25-(OH)2D3-receptor complex on sucrose density gradients, 3.8 S, was the same as in normal cells. This patient, therefore, appeared to have a receptor-positive form of resistance to 1,25-(OH)2D3. To document resistance to 1,25-(OH)2D3 in the fibroblasts we developed a method for detection of 1,25-(OH)2D3 action in normal skin fibroblasts. Following treatment of normal cell monolayers with 1,25-(OH)2D3 there was more than a 20-fold increase of 25-hydroxy-vitamin D-24-hydroxylase (24-hydroxylase) activity. Treatment of 10 control cell strains with 1,25-(OH)2D3 for 8 h increased the formation of 24,25-dihydroxy-vitamin D3 from 25-hydroxyvitamin D3 in cell sonicates from less than 0.02 to 0.11-0.27 pmol/min per mg protein. When cells from the patient with vitamin D-dependent rickets, type II were treated with 1,25-(OH)2D3 in a similar manner, maximal 24-hydroxylase activity was only 0.02 pmol/min per mg protein, less than a fifth the lower limit of normal. 24-Hydroxylase activity in fibroblasts from the parents of the patient increased normally following treatment with 1,25-(OH)2D3. We conclude that impaired induction of 24-hydroxylase in the presence of normal receptor binding is evidence for postreceptor resistance to the action of 1,25-(OH)2D3.