Induction of vascular endothelial growth factor in human astrocytes by lead. Involvement of a protein kinase C/activator protein-1 complex-dependent and hypoxia-inducible factor 1-independent signaling pathway.
Induction of vascular endothelial growth factor in human astrocytes by lead. Involvement of a protein kinase C/activator protein-1 complex-dependent and hypoxia-inducible factor 1-independent signaling pathway.
复制标题
DOI：
10.1074/jbc.m002185200
复制
发表时间：
2000-09
期刊：
影响因子：
--
通讯作者：
Mir Ahamed Hossain;Christopher M. L. S. Bouton;Jonathan Pevsner;John Laterra
中科院分区：
文献类型：
--
作者：
Mir Ahamed Hossain;Christopher M. L. S. Bouton;Jonathan Pevsner;John Laterra
铅神经毒性的潜在机制尚未完全阐明。cDNA表达微阵列分析鉴定了永生化人胎儿星形胶质细胞（SV-FHA）中的铅敏感基因。在所表达的代表基因中，血管内皮生长因子（VEGF）是最敏感的基因之一。铅诱导VEGF mRNA的3倍和VEGF蛋白约2倍，最大的mRNA诱导后，与10微米醋酸铅孵育24小时。佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA），一种有效的蛋白激酶C（PKC）激活剂，增加VEGF mRNA的2倍，GF-109203的PKC抑制作用完全阻断了铅诱导的VEGF。显性负性PKC-α的表达完全抑制了铅对VEGF mRNA的诱导。铅激活了转录因子AP-1，并使AP-1依赖的荧光素酶表达增加了2倍以上。转染c-jun显性阴性的细胞有效地抑制AP-1激活和VEGFmRNA诱导铅。铅（86%）和PMA（96%）可中度增加SV-FHA中缺氧诱导因子1（HIF-1）的活性。GF-109203预处理完全抑制铅和PMA的这些作用。然而，铅并没有改变HIF-1依赖的荧光素酶的表达和HIF-1 α显性阴性对VEGF mRNA的诱导铅没有影响。这些结果表明，铅诱导血管内皮生长因子表达SV-FHA通过PKC/AP-1依赖和HIF-1非依赖的信号通路。
The mechanism(s) underlying lead neurotoxicity are not fully elucidated. cDNA expression microarray analysis identified lead-sensitive genes in immortalized human fetal astrocytes (SV-FHA). Of the represented genes expressed, vascular endothelial growth factor (VEGF) was one of the most sensitive. Lead induced VEGF mRNA 3-fold and VEGF protein approximately 2-fold with maximum mRNA induction following incubation with 10 micrometer lead acetate for 24 h. Phorbol 12-myristate 13-acetate (PMA), a potent protein kinase C (PKC) activator, increased VEGF mRNA 2-fold and PKC inhibition by GF-109203 completely blocked VEGF induction by lead. Expression of dominant-negative PKC-epsilon, but not PKC-alpha, completely inhibited VEGF mRNA induction by lead. Lead activated the transcription factor AP-1 and increased AP-1-dependent luciferase expression >2-fold. Transfection of cells with a c-jun dominant-negative effectively inhibited both AP-1 activation and VEGF mRNA induction by lead. Hypoxia-inducible factor 1 (HIF-1) activity in SV-FHAs was moderately increased by lead (86%) and PMA (96%). Pretreatment with GF-109203 completely inhibited these effects of lead and PMA. However, lead did not alter HIF-1-dependent luciferase expression and a HIF-1alpha dominant-negative had no effects on the induction of VEGF mRNA by lead. These findings indicate that lead induces VEGF expression in SV-FHAs via a PKC/AP-1-dependent and HIF-1-independent signaling pathway.