ER calcium discharge stimulates GDNF gene expression through MAPK-dependent and -independent pathways in rat C6 glioblastoma cells
ER calcium discharge stimulates GDNF gene expression through MAPK-dependent and -independent pathways in rat C6 glioblastoma cells
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DOI：
10.1016/j.neulet.2006.06.027
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发表时间：
2006-09
影响因子：
2.5
通讯作者：
K. Oh‐hashi;Masayo Kaneyama;Y. Hirata;K. Kiuchi
中科院分区：
文献类型：
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作者：
K. Oh‐hashi;Masayo Kaneyama;Y. Hirata;K. Kiuchi
胶质细胞源性神经营养因子（GDNF）是一种神经营养和分化因子，在多种病理生理条件下表达，但其调节信号尚未阐明。在此，我们发现毒胡萝卜素诱导内质网 (ER) Ca2+ 放电诱导大鼠 C6 胶质母细胞瘤细胞中 GDNF mRNA 以及 COX2 和 GRP78 表达。 GDNF mRNA 立即被毒胡萝卜素诱导并在 2 小时达到峰值，由外显子 3 和外显子 4 组成的替代转录物似乎是最容易诱导的。尽管存在细胞内 Ca2+ 扰动，但 Ca2+ 依赖性 PKC 并不负责这种诱导。相反，PKCδ 特异性抑制剂 Rottlerin 抑制了毒胡萝卜素诱导的 GDNF mRNA 表达。另一方面，毒胡萝卜素瞬时增强丝裂原激活蛋白激酶（MAPK）途径的磷酸化状态，同时包括细胞外信号调节激酶（Erk）、p38 MAPK和c-JUN氨基末端激酶1（JNK1）；而针对 MEK1 和 JNK 的特异性抑制剂仅降低毒胡萝卜素诱导的 GDNF mRNA 表达。此外，泛 PKC 抑制剂 (Ro-31-8220) 减弱了毒胡萝卜素增强的 Erk1/2 和 JNK1 磷酸化水平，而 Rottlerin 则不然。因此，本研究表明，毒胡萝卜素刺激的 ER Ca2+ 放电通过 C6 胶质母细胞瘤细胞中 MAPK 依赖性和非依赖性途径上调 GDNF 基因表达。
Glial cell line-derived neurotrophic factor (GDNF), a neurotrophic and differentiation factor, is expressed under several pathophysiological conditions but its regulatory signals have not yet been clarified. Here, we found that endoplasmic reticulum (ER) Ca2+discharge by thapsigargin induced GDNF mRNA as well as COX2 and GRP78 expression in rat C6 glioblastoma cells. GDNF mRNA was immediately induced and peaked at 2h by thapsigargin, and the alternative transcript consisting of exon 3 and exon 4 appeared to be most inducible. In spite of intracellular Ca2+perturbation, Ca2+-dependent PKC was not responsible for this induction. Instead, a PKCδ-specific inhibitor, rottlerin, suppressed the thapsigargin-induced GDNF mRNA expression. On the other hand, thapsigargin transiently enhanced phosphorylation status of mitogen-activated protein kinase (MAPK) pathway, including extracellular signal-regulated kinase (Erk), p38 MAPK and c-JUN amino-terminal kinase1 (JNK1) simultaneously; whereas specific inhibitors against MEK1 and JNK only reduced the thapsigargin-induced GDNF mRNA expression. In addition, a pan-PKC inhibitor (Ro-31-8220) attenuated the thapsigargin-enhanced phosphorylation levels of Erk1/2 and JNK1, whereas rottlerin did not. Thus, the present study demonstrated that the thapsigargin-stimulated ER Ca2+discharge up-regulated GDNF gene expression through both MAPK-dependent and -independent pathways in C6 glioblastoma cells.