The chondrogenic transcription factor Sox9 is a target of signaling by the parathyroid hormone-related peptide in the growth plate of endochondral bones.
The chondrogenic transcription factor Sox9 is a target of signaling by the parathyroid hormone-related peptide in the growth plate of endochondral bones.
复制标题
DOI：
10.1073/pnas.98.1.160
复制
发表时间：
2001-01
影响因子：
11.1
通讯作者：
Wendong Huang;Ung-il Chung;H. Kronenberg;B. Crombrugghe
中科院分区：
文献类型：
--
作者：
Wendong Huang;Ung-il Chung;H. Kronenberg;B. Crombrugghe
在软骨内骨的生长板中，甲状旁腺激素（PTH）相关肽（PTHrP）调节软骨细胞从肥大前软骨细胞向肥大软骨细胞成熟的速率。使用对Sox 9的丝氨酸181（S（181））（Sox 9的两个共有蛋白激酶A磷酸化位点之一）磷酸化的特异性抗体，我们表明PTHrP的加入强烈增加了用SOX 9和PTH/PTHrP受体表达载体转染的COS 7细胞中SOX 9的磷酸化。PTHrP也增加了SOX 9依赖的活性软骨细胞特异性增强基因II型胶原蛋白（Col 2a 1）在瞬时转染实验。这种增强子活性的增加并没有发生在Sox 9突变体中，该突变体在其两个共有蛋白激酶A磷酸化位点中具有丝氨酸至丙氨酸的取代。与这些结果一致，PTHrP也增加了大鼠软骨肉瘤细胞以及用PTH/PTHrP受体表达质粒转染的10 T1/2间充质细胞中Col 2a 1 mRNA水平。在生长板的前肥大软骨细胞或PTH/PTHrP受体无效突变体的任何软骨细胞中均未检测到Sox 9在S（181）处的磷酸化。相反，在野生型小鼠胚胎中，先前的免疫组织化学实验表明，在S（181）磷酸化的Sox 9几乎只在前肥大区的软骨细胞中检测到。Sox 9，无论磷酸化状态，存在于所有的软骨细胞的两种基因型，除了肥大软骨细胞。我们的研究结果表明，Sox 9是PTHrP信号在生长板中的前肥大软骨细胞的目标。我们假设Sox 9介导生长板中PTHrP的至少一些作用，并且Sox 9的PTHrP依赖性转录活性增加有助于维持前肥大区细胞的软骨细胞表型，并抑制其成熟为肥大软骨细胞。
In the growth plate of endochondral bones, parathyroid hormone (PTH)-related peptide (PTHrP) regulates the rate of chondrocyte maturation from prehypertrophic chondrocytes to hypertrophic chondrocytes. Using an antibody specific for Sox9 phosphorylated at serine 181 (S(181)), one of the two consensus protein kinase A phosphorylation sites of Sox9, we showed that the addition of PTHrP strongly increased the phosphorylation of SOX9 in COS7 cells transfected with both SOX9- and PTH/PTHrP receptor-expressing vectors. PTHrP also increased the SOX9-dependent activity of chondrocyte-specific enhancers in the gene for type II collagen (Col2a1) in transient transfection experiments. This increased enhancer activity did not occur with a Sox9 mutant harboring serine-to-alanine substitutions in its two consensus protein kinase A phosphorylation sites. Consistent with these results, PTHrP also increased Col2a1 mRNA levels in rat chondrosarcoma cells as well as 10T1/2 mesenchymal cells transfected with a PTH/PTHrP receptor expressing plasmid. No phosphorylation of Sox9 at S(181) was detected in prehypertrophic chondrocytes of the growth plate or any chondrocytes of PTH/PTHrP receptor null mutants. In contrast in wild-type mouse embryos, previous immunohistochemistry experiments indicated that Sox9 phosphorylated at S(181) was detected almost exclusively in chondrocytes of the prehypertrophic zone. Sox9, regardless of the phosphorylation state, was present in all chondrocytes of both genotypes except hypertrophic chondrocytes. Our results indicated that Sox9 is a target of PTHrP signaling in prehypertrophic chondrocytes in the growth plate. We hypothesize that Sox9 mediates at least some effects of PTHrP in the growth plate and that the PTHrP-dependent increased transcriptional activity of Sox9 helps maintain the chondrocyte phenotype of cells in the prehypertrophic zone and inhibits their maturation to hypertrophic chondrocytes.