Prostaglandin E2 enhances osteoclastic differentiation of precursor cells through protein kinase A-dependent phosphorylation of TAK1
Prostaglandin E2 enhances osteoclastic differentiation of precursor cells through protein kinase A-dependent phosphorylation of TAK1
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DOI：
10.1074/jbc.m411189200
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发表时间：
2005-03-25
影响因子：
4.8
通讯作者：
Takahashi, N
中科院分区：
文献类型：
--
作者：
Kobayashi, Y;Mizoguchi, T;Takahashi, N
前列腺素E-2（PGE（2））协同增强前体细胞的NF-κ B配体（RANKL）诱导的骨细胞分化的受体激活剂。本研究旨在探讨PGE 2促进破骨细胞分化的机制。PGE 2通过EP 2和EP 4前列腺素受体促进RANKL诱导的RAW264.7细胞向成骨细胞分化。RAW264.7细胞中RANKL诱导的I kappa B α降解以及p38 MAPK和c-Jun N-末端激酶的磷酸化被PGE 2以cAMP依赖性蛋白激酶A（PKA）依赖性方式上调，表明EP 2和EP 4信号与RANK信号交叉。转化生长因子β激活激酶1（TAK 1）是一种重要的MAPK激酶，在409 - 412位氨基酸处具有PKA识别位点。PKA直接磷酸化转染野生型TAK 1但不转染Ser（412）-> Ala突变体TAK 1的RAW264.7细胞中的TAK 1。Ser（412）-> Ala TAK 1在PKA促进I κ B α降解、p38 MAPK磷酸化和PGE（2）促进RAW264.7细胞成骨分化中起显性负突变作用。此外，毛喉素增强肿瘤坏死因子α诱导的I κ B α降解，p38 MAPK磷酸化，并在RAW 264.7细胞的骨细胞分化。Ser 4123 AlaTAK 1可阻断forskolin对肿瘤坏死因子α诱导的上述细胞事件的刺激作用。Ser 412 - 3AlaTAK 1也能抑制Forskolin诱导的脂多糖诱导的RAW264.7细胞IL-6产生的上调。这些结果表明PKA对TAK 1中Ser（412）残基的磷酸化对于cAMP/PKA诱导的前体细胞中骨细胞分化和细胞因子产生的上调是必需的。
Prostaglandin E-2 (PGE(2)) synergistically enhances the receptor activator for NF-kappa B ligand (RANKL)-induced osteoclastic differentiation of the precursor cells. Here we investigated the mechanisms of the stimulatory effect of PGE2 on osteoclast differentiation. PGE2 enhanced osteoclastic differentiation of RAW264.7 cells in the presence of RANKL through EP2 and EP4 prostanoid receptors. RANKL-induced degradation of I kappa B alpha and phosphorylation of p38 MAPK and c-Jun N-terminal kinase in RAW264.7 cells were up-regulated by PGE2 in a cAMP-dependent protein kinase A (PKA)-dependent manner, suggesting that EP2 and EP4 signals cross-talk with RANK signals. Transforming growth factor beta-activated kinase 1 (TAK1), an important MAPK kinase kinase in several cytokine signals, possesses a PKA recognition site at amino acids 409 - 412. PKA directly phosphorylated TAK1 in RAW264.7 cells transfected with wild-type TAK1 but not with the Ser(412) -> Ala mutant TAK1. Ser(412) -> Ala TAK1 served as a dominant-negative mutant in PKA-enhanced degradation of I kappa B alpha, phosphorylation of p38 MAPK, and PGE(2)-enhanced osteoclastic differentiation in RAW264.7 cells. Furthermore, forskolin enhanced tumor necrosis factor alpha-induced I kappa B alpha degradation, p38 MAPK phosphorylation, and osteoclastic differentiation in RAW264.7 cells. Ser412 3 Ala TAK1 abolished the stimulatory effects of forskolin on those cellular events induced by tumor necrosis factor alpha. Ser412 3 Ala TAK1 also inhibited the forskolin-induced up-regulation of interleukin 6 production in RAW264.7 cells treated with lipopolysaccharide. These results suggest that the phosphorylation of the Ser(412) residue in TAK1 by PKA is essential for cAMP/PKA-induced up-regulation of osteoclastic differentiation and cytokine production in the precursor cells.