Molecular pharmacological study about mechanisms of increased AT1 receptor expression in the brain of spontaneously hypertensive rats

自发性高血压大鼠脑内AT1受体表达增加机制的分子药理学研究

• 批准号: 13672300
• 负责人: KUBO Takao
• 金额: $ 2.11万
• 依托单位: Showa Pharmaceutical University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13672300/
• 关键词: angiotensin; receptor; hypertension; central nervous system; hypothalamus; AT1 receptors; gene

The angiotensin type 1 (AT1) receptor gene is overexpressed in the brain of spontaneously hypertensive rats (SHR) and this overexpression of the receptor is an important causal factor for hypertension in SHR. We examined whether there are mutations responsible for the overexpression of the AT1 receptor gene in SHR AT1 receptor promoter region. Sequence analysis identified one single base mutation unique to the SHR AT1 receptor gene promoter region when compared to that of Wistar Kyoto rats (WKY). Electrophoretic mobility shift assay (EMSA) showed that there were 3 major similar DNA protein complexes against WKY and SHR oligonucleotide. Additionally, the oligonucleotide bearing the SHR sequence produced an extra band. However, promoter/luciferase reporter assay demonstrated that the promoter activity of SHR AT1 receptor promoters (-2050 to +57) was lower than that of WKY. Next, we examined whether changes in the level of the transcriptional factors responsible for AT1 receptor gene expression are involved in the overexpression of the AT1 receptor gene hi SHR brain. EMSA showed that Sp1 and AP2 are increased in nuclear extracts of hypothalamus from SHR. Spl decoy phosphorothioate oligodeoxynucleotides injected into the lateral ventricle produced a decreased in blood pressure in SHR. The findings suggest that Sp1 and AP2 levels are increased in the hypothalamus of SHR. These change in Sp1 an AP2 might be involved in developmen of hypertension in SHR.

血管紧张素1型（AT 1）受体基因在自发性高血压大鼠（SHR）脑中过度表达，这种受体的过度表达是SHR高血压的重要原因。我们检测了SHR AT 1受体启动子区是否存在导致AT 1受体基因过表达的突变。序列分析发现，与Wistar京都大鼠（WKY）相比，SHR AT 1受体基因启动子区有一个独特的单碱基突变。电泳迁移率变动分析（EMSA）显示，WKY和SHR寡核苷酸的DNA蛋白复合物主要有3种相似。此外，携带SHR序列的寡核苷酸产生额外条带。而启动子/荧光素酶报告基因检测表明，SHR AT 1受体启动子（-2050 ~+57）的启动子活性低于WKY。接下来，我们研究了负责AT 1受体基因表达的转录因子水平的变化是否参与了SHR脑中AT 1受体基因的过表达。EMSA结果显示，SHR下丘脑核提取物中SP 1和AP 2含量增加。侧脑室注射Spl诱饵硫代磷酸寡脱氧核苷酸可降低SHR血压。研究结果表明，自发性高血压大鼠下丘脑中Sp1和AP 2水平升高。Sp1和AP 2的这些变化可能参与了SHR高血压的发生发展。

项目成果

Takao Kubo et al.: "Renin antisense injected intraventricularly decreases blood pressure in spontaneously hypertensive rats"Brain Research Bulletin. 56. 23-28 (2001)

Takao Kubo 等人：“脑室内注射反义肾素可降低自发性高血压大鼠的血压”《脑研究通报》。

Toshie Kambe, Hitoshi Hiruki, Takao Kubo: "Existence of a mutation of Angiotensin AT1 receptor gene promoter region involved in inhibition of AT1 receptor gene transcription in spontaneously hypertensive rats."Hypertension Research. 26 (3). 245-250 (2003)

Toshie Kambe、Hitoshi Hiruki、Takao Kubo：“血管紧张素 AT1 受体基因启动子区域存在突变，参与抑制自发性高血压大鼠 AT1 受体基因转录。”高血压研究。

Takao Kubo et al.: "Activation of hypothalamic angiotensin...."Brain Research. 953・3. 232-245 (2002)

Takao Kubo 等：“下丘脑血管紧张素的激活......”脑研究 953・3（2002）。

Takao Kubo et al.: "Renin antisense injected intraventricularly …"Brain Res. Bull.. 56・1. 23-28 (2001)

Takao Kubo 等：“脑室内注射肾素反义酶……”Brain Res. 56・1 (2001)。

Takao Kubo et al.: "Activation of hypothalamic angiotensin receptors produces pressor responses via cholinergic inputs to the rostral ventrolateral medulla in normotensive and hypertensive rats"Brain Research. 953. 232-245 (2002)

Takao Kubo 等人：“在正常血压和高血压大鼠中，下丘脑血管紧张素受体的激活通过胆碱能输入到头端腹外侧延髓产生升压反应”大脑研究。