一个新的高血压病相关基因的克隆和表达

Cloning and expression of a novel gene related to hypertension

目的寻找和克隆新的高血压病相关基因，探讨高血压病的发病机制。方法应用差异显示筛选的方法，对正常（ＷＫＹ）大鼠和自发性高血压病大鼠（ＳＨＲ）血管平滑肌细胞进行ＲＮＡｍａｐｐｉｎｇ分析，选择下调的ｃＤＮＡ进行克隆。结果获得一个新的ｃＤＮＡ，其长度为４１６０ｂｐ，可编码５５１个氨基酸，蛋白质分子量为６２６４４。Ｎｏｒｔｈｅｒｎｂｌｏｔ分析证明，这一基因不仅存在于血管平滑肌细胞中，而且也广泛分布在大鼠心、肾、脑、肺和肝组织中。这一基因在ＳＨＲ大鼠的心、肾、脑、肝中低表达，在ＷＫＹ大鼠高表达；血管紧张素ＩＩ、内皮素－１、ＩＬ－１等致血管平滑肌细胞增殖和高血压的因素可以抑制这一基因的表达，其作用可为相应的拮抗剂所阻断；心钠素、降钙素基因相关肽、肾上腺髓质降压素等抑制血管平滑肌细胞（ＶＳＭＣ）增殖和降低高血压的因素可以上调这一基因的表达。结论获得了一种新的与血管平滑肌细胞增殖或高血压相关的基因，它可能拮抗ＶＳＭＣ增殖，在高血压的发生中起重要作用。

bjective To search and clone novel genes related to hypertension. Methods Using differential display, a RNA mapping method, we identified differentially expressed RNAs from cultured VSMCs of WKY and SHR. Downexpressed cDNAs of WKY were cloned. Results A novel cDNA (rHRG1) obtained contained 4 160 bp nucleotides and an open reading frame which encoded 551 amino acid residues. Its molecular weight was 62 644. Northern blot analysis showed that the mRNA was expressed not only in VSMCs but in various rat tissues (heart, liver, brain, lung and kidney). Besides, the expression of rHRG1 mRNA in various tissues (heart, liver, brain and kidney) of WKY rat was higher than that in those tissues of SHR. Semiquantitative RTPCR analysis showed that the expression of rHRG1 mRNA was downregulated by treating cells with angiotensinⅡ, endothelinⅠ or interleukinⅠ, VSMCs proliferation and hypertensionstimulating factor, but was upregulated when treating cells with ANF, CGRP or adrenomedullin which could inhibit the proliferation of VSMCs and attenuate hypertension. These effects could be blocked or attenuated by corresponding antagonists or antibodies. Conclusion The isolated novel rat cDNA (rHRG1) is related to VSMCs proliferation or hypertension. It may antagonize the proliferation of VSMCs and may be involved in the formation of hypertension.