Regulation of HMG-CoA synthase and HMG-CoA reductase by insulin and epidermal growth factor in HaCaT keratinocytes
Regulation of HMG-CoA synthase and HMG-CoA reductase by insulin and epidermal growth factor in HaCaT keratinocytes
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DOI：
10.1046/j.1523-1747.2000.00822.x
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发表时间：
2000-01-01
影响因子：
6.5
通讯作者：
Wittern, KP
中科院分区：
文献类型：
--
作者：
Harris, IR;Höppner, H;Wittern, KP
通过类异戊二烯/甲羟戊酸途径合成胆固醇是角质形成细胞生长和分化以及维持角质层脂质层所必需的。3-羟基-3-甲基戊二酰辅酶A合酶催化类异戊二烯/甲羟戊酸合成的第一步，并在某些条件下控制进入该途径的通量。我们研究了是否选择生长因子和激素可以增加角质形成细胞中的3-羟基-3-甲基戊二酰辅酶A合酶mRNA。用北方印迹法证明10 μ g/ml胰岛素和0.1 μ g/ml表皮生长因子均使3-羟基-3-甲基戊二酰辅酶A合酶mRNA的稳态水平分别增加2.5和6倍。表皮生长因子和胰岛素也增加了3-羟基-3-甲基戊二酰辅酶A还原酶的活性。3-羟基-3-甲基戊二酰辅酶A合成酶启动子活性在荧光素酶报告基因构建体中增加2倍胰岛素和2.9倍表皮生长因子。当固醇调节元件中的突变被引入到3-羟基-3-甲基戊二酰辅酶A合成酶启动子中时，胰岛素不增加活性，但表皮生长因子增加活性。在3-羟基-3-甲基戊二酰辅酶A合成酶启动子中的AP-1位点的突变不影响用胰岛素或表皮生长因子处理后活性的增加。因此，3-羟基-3-甲基戊二酰辅酶A合成酶在角质形成细胞中的表达受胰岛素和表皮生长因子通过不同的机制调节。这些结果表明激素和生长因子在控制表皮胆固醇合成中的作用。
Synthesis of cholesterol, via the isoprenoid/mevalonate pathway, is required for keratinocyte growth and differentiation, and maintenance of the stratum corneum lipid lamellae. 3-hydroxy-3-methylglutaryl coenzyme A synthase catalyzes the first step in isoprenoid/mevalonate synthesis and under some conditions controls the flux into the pathway. We have investigated whether selected growth factors and hormones could increase 3-hydroxy-3-methylglutaryl coenzyme A synthase mRNA in keratinocytes. Northern blotting was used to demonstrate that 10 mu g per ml insulin and 0.1 mu g per ml epidermal growth factor both increased steady-state levels of 3-hydroxy-3-methylglutaryl coenzyme A synthase mRNA by 2.5 and 6-fold, respectively. Epidermal growth factor and insulin also increased 3-hydroxy-3-methylglutaryl coenzyme A reductase enzyme activity. 3-hydroxy-3-methylglutaryl coenzyme A synthase promoter activity in a luciferase reporter construct was increased 2-fold by insulin and 2.9-fold by epidermal growth factor. When a mutation in the sterol regulatory element was introduced into the 3-hydroxy-3-methylglutaryl coenzyme A synthase promoter, activity was not increased by insulin, but was increased by epidermal growth factor. Mutation of an AP-1 site in the 3-hydroxy-3-methylglutaryl coenzyme A synthase promoter did not affect the increase in activity following treatment with insulin or epidermal growth factor. Therefore, 3-hydroxy-3-methylglutaryl coenzyme A synthase expression in keratinocytes is regulated by insulin and epidermal growth factor by different mechanisms. These results suggest a role for hormones and growth factors in the control of epidermal cholesterol synthesis.