PI3K/AKT regulates aggrecan gene expression by modulating Sox9 expression and activity in nucleus pulposus cells of the intervertebral disc.
PI3K/AKT regulates aggrecan gene expression by modulating Sox9 expression and activity in nucleus pulposus cells of the intervertebral disc.
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DOI：
10.1002/jcp.21904
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发表时间：
2009-12
影响因子：
5.6
通讯作者：
Risbud, Makarand V.
中科院分区：
文献类型：
--
作者：
Cheng, Chin-Chang;Uchiyama, Yoshiyasu;Hiyama, Akihiko;Gajghate, Sachin;Shapiro, Irving M.;Risbud, Makarand V.
该研究的目的是检验以下假设：PI3K/AKT 信号通路调节椎间盘主要细胞外基质成分聚集蛋白聚糖在髓核细胞中的表达。用 PI3K 抑制剂处理原代大鼠髓核细胞，以测量基因和蛋白质表达的变化。此外，用各种荧光素酶报告质粒转染细胞以研究聚集蛋白聚糖基因表达的调节机制。我们发现用 PI3K 抑制剂 LY294002 处理髓核细胞会导致聚集蛋白聚糖表达减少和硫酸化糖胺聚糖沉积减少。此外，显性失活 (DN)-PI3K 或 DN-AKT 的药理学抑制或共表达导致聚集蛋白聚糖启动子活性下调。组成型活性 (CA)-PI3K 的表达显着诱导聚集蛋白聚糖启动子活性。我们观察到 PI3K 维持了 Sox9 基因的表达和活性：抑制 PI3K/AKT 会导致 Sox9 表达减少、启动子活性降低并介导 Sox9 转录活性降低。 PI3K 效应与 Sox9 C 末端反式激活结构域 (TAD) 的磷酸化状态无关。最后，我们注意到在髓核细胞中，PI3K 信号传导控制 p300 的反式激活（p300-TAD 活性），p300 是 Sox9 的重要转录共激活因子。这些研究的结果首次证明 PI3K/AKT 信号传导控制聚集蛋白聚糖基因表达，部分是通过调节髓核细胞中的 Sox9 表达和活性。
The goal of the investigation was to test the hypothesis that the PI3K/AKT signaling pathway regulates the expression of the major extracellular matrix component of the intervertebral disc, aggrecan, in nucleus pulposus cells. Primary rat nucleus pulposus cells were treated with PI3K inhibitor to measure changes in gene and protein expression. In addition, cells were transfected with various luciferase reporter plasmids to investigate mechanisms of regulation of aggrecan gene expression. We found that treatment of nucleus pulposus cells with a PI3K inhibitor, LY294002 resulted in decreased expression of aggrecan and a reduction in deposition of sulfated glycosaminoglycans. Moreover, pharmacological suppression or co-expression of dominant negative (DN)-PI3K or DN-AKT resulted in downregulation of aggrecan promoter activity. Expression of constitutively active (CA)-PI3K significantly induced aggrecan promoter activity. We observed that PI3K maintained Sox9 gene expression and activity: inhibition of PI3K/AKT resulted in decreased Sox9 expression, lowered promoter activity and mediated a reduction in Sox9 transcriptional activity. PI3K effects were independent of phosphorylation status of C-terminus transactivation domain (TAD) of Sox9. Finally, we noted that in nucleus pulposus cells, PI3K signaling controlled transactivation of p300 (p300-TAD activity), an important transcriptional coactivator of Sox9. Results of these studies demonstrate for the first time that PI3K/AKT signaling controls aggrecan gene expression, in part by modulating Sox9 expression and activity in cells of the nucleus pulposus.
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影响因子：
4.8
作者：
Tsai, Tsung-Ting;Danielson, Keith G.;Risbud, Makarand V.
通讯作者：
Risbud, Makarand V.
影响因子：
11.4
作者：
Lefebvre, V;Li, P;de Crombrugghe, B
通讯作者：
de Crombrugghe, B
影响因子：
5.3
作者：
Han, Yu;Lefebvre, Veronique
通讯作者：
Lefebvre, Veronique
影响因子：
4.8
作者：
Sekiya, I;Tsuji, K;Noda, M
通讯作者：
Noda, M
影响因子：
4.8
作者：
Sang, NL;Stiehl, DP;Caro, J
通讯作者：
Caro, J