组胺对星形胶质细胞Egr-1表达的调节作用

 目的: 探讨组胺对星形胶质细胞早期反应生长因子-1(Egr-1)表达是否具有调节作用。方法: 将野生型(WT)和组氨酸脱羧酶敲除(HDC-KO)小鼠及组胺处理的HDC-KO小鼠取脑,并提取皮层组织总RNA。将原代培养的大鼠皮层星形胶质细胞分别给予不同浓度的组胺(10^-8、10^-7、10^-6、10^-5或10^-4 mol/L)处理15、30、60、120或240 min。组胺H₁、H₂受体拮抗剂分别于组胺给药前15 min加入。组胺处理完毕后,提取细胞总RNA或蛋白。利用real-time PCR和Western blot测定Egr-1的表达。结果: 与WT小鼠相比,HDC-KO小鼠大脑皮层Egr-1的mRNA表达量显著降低,而外源性给予组胺则能促进其Egr-1的mRNA表达。在培养的星形胶质细胞上,组胺可促进Egr-1的mRNA表达,其中10^-5 mol/L的组胺作用最强,而组胺(10^-5 mol/L)处理30 min时Egr-1的mRNA表达量达到峰值,相应的Egr-1蛋白表达于60 min时显著增高,该作用可被组胺H₁受体拮抗剂而非H₂受体拮抗剂显著抑制。结论: 组胺对大脑皮层组织及培养的星形胶质细胞Egr-1表达具有上调作用,该作用与激动组胺H₁受体有关。

Effects of histamine on mRNA expression of Egr-1 in astrocytes

AIM: To explore whether histamine can regulate the expression of early growth response factor-1(Egr-1) in the cerebral cortex astrocytes.METHODS: Normal wild-type(WT) mice, histidine decarboxylase knockout(HDC-KO) mice and histamine treated HDC-KO mice were sacrificed for extracting the total RNA of the cerebral cortex. Primary cultured rat cortical astrocytes were treated with histamine at concentrations of 10^-8, 10^-7, 10^-6, 10^-5 or 10^-4 mol/L for 15, 30, 60, 120 or 240 min. H₁ or H₂ receptor antagonists were pretreated for 15 min before histamine treatment. After histamine treatment, the cell total RNA or protein was extracted. The expression of Egr-1 at mRNA and protein levels was determined by real-time PCR and Western blot.RESULTS: The mRNA level of Egr-1 in cerebral cortex of HDC-KO mice was significantly lower than that in WT mice, while exogenous histamine induced the mRNA expression of Egr-1 in HDC-KO mice. In cultured astrocytes, histamine induced the mRNA expression of Egr-1. The maximum increase in the mRNA level of Egr-1 was produced by histamine at concentration of 10^-5 mol/L. In addition, histamine-induced Egr-1 mRNA accumulation peaked at 30 min after commencing stimulation, while histamine significantly increased Egr-1 protein expression at 60 min. Furthermore, histamine-induced Egr-1 expression was inhibited by H₁ receptor antagonist but not H₂ receptor antagonist.CONCLUSION: Histamine up-regulates the Egr-1 expression in cerebral cortex and cultured astrocytes, which may attribute to H₁ receptor activation.