Pituitary adenylate cyclase-activating polypeptide induces gene expression of the catecholamine synthesizing enzymes, tyrosine hydroxylase and dopamine beta hydroxylase, through 3',5'-cyclic adenosine monophosphate- and protein kinase C-dependent mechanisms in cultured porcine adrenal medullary chromaffin cells
Pituitary adenylate cyclase-activating polypeptide induces gene expression of the catecholamine synthesizing enzymes, tyrosine hydroxylase and dopamine beta hydroxylase, through 3',5'-cyclic adenosine monophosphate- and protein kinase C-dependent mechanisms in cultured porcine adrenal medullary chromaffin cells
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DOI：
10.1016/s0143-4179(96)90084-0
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发表时间：
1996-04-01
期刊：
影响因子：
2.9
通讯作者：
Takuwa, Y
中科院分区：
文献类型：
--
作者：
Isobe, K;Yukimasa, N;Takuwa, Y
垂体腺苷酸环化酶激活多肽 (PACAP) 是儿茶酚胺分泌的有效刺激剂，可增加培养的猪肾上腺髓质嗜铬细胞中儿茶酚胺的产生。 PACAP 诱导儿茶酚胺合成酶、酪氨酸羟化酶 (TH) 和多巴胺 B-羟化酶 (DBH) mRNA 呈剂量和时间依赖性增加，在 8-16 小时分别出现最大 6 倍和 4 倍增加。刺激 TH 和 DBH 基因表达的半最大和最大有效 PACAP 浓度分别为 0.5 和 3 nM。在 PACAP 刺激的细胞中，TH 蛋白水平在 16-24 小时也显示出比未刺激的基础水平有所增加。我们之前证明 PACAP 激活肾上腺髓质细胞中的磷脂酶 C 和腺苷酸环化酶。单独添加毛喉素可诱导 TH 和 DBH mRNA 表达增加。磷酸二酯酶抑制剂 3-异丁基-1-甲基黄嘌呤增强了 PACAP 对 TH 和 DBH mRNA 的诱导。添加蛋白激酶 C 激活剂佛波醇 12-肉豆蔻酸酯 13-乙酸酯 (PMA) 也会导致 TH 和 DBH mRNA 水平增加。在用 PMA 预处理 24 小时的蛋白激酶 C 下调细胞中，PACAP 对 TH 和 DBH 基因表达的刺激作用减弱。这些结果表明 cAMP 和蛋白激酶 C 介导 PACAP 诱导的 TH 和 DBH 基因表达。用EGTA去除细胞外Ca2+增强了PAGAP诱导的细胞cAMP和TH和DBH mRNA水平的增加，表明Ca2+对TH和DBH mRNA的诱导具有抑制作用。 总之，本研究表明PACAP通过激活cAMP和蛋白激酶C信号通路协调上调TH和DBH的基因表达，导致模拟儿茶酚胺合成，而C-a2+负调节猪肾上腺髓质细胞中的 TH 和 DBH 基因表达。
Pituitary adenylate cyclase-activating polypeptide (PACAP), a potent stimulant of catecholamine secretion, increased catecholamine production in cultured porcine adrenal medullary chromaffin cells. PACAP induced dose- and time-dependent increases in mRNAs for the catecholamine synthesizing enzymes, tyrosine hydroxylase (TH) and dopamine B-hydroxylase (DBH), with maximal 6- and 4-fold increases occurring at 8-16 h, respectively. The half-maximally and maximally effective PACAP concentrations for stimulation of TH and DBH gene expression were 0.5 and 3 nM, respectively. The TH protein level also showed an increase over the unstimulated basal level at 16-24 h in PACAP-stimulate cells.We previously demonstrated that PACAP activates both phospholipase C and adenylate cyclase in adrenal medullary cells. Addition of forskolin alone induced increases in mRNA expression of both TH and DBH. The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine potentiated the induction of TH and DBH mRNAs by PACAP. Addition of the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) also caused increases in TH and DBH mRNA levels. In protein kinase C-downregulated cells pretreated with PMA for 24 h, the stimulatory effect of PACAP on TH and DBH gene expression was diminished. These results suggest that cAMP and protein kinase C mediate the PACAP-induced TH and DBH gene expression. Removal of extracellular Ca2+ with EGTA enhanced the PAGAP-induced increases in both cellular cAMP and mRNA levels of TH and DBH, suggesting that Ca2+ has an inhibitory effect on the induction of TH and DBH mRNAs.In conclusion, the present study indicates that PACAP coordinately upregulates the gene expression of both TH and DBH by activating the cAMP and protein kinase C signaling pathways, leading to simulation of cate-cholamine sythesis, while C-a2+ negatively regulates TH and DBH gene expression in porcine adrenal medullary cells.