KALLISTATIN IN HYPERTENSION

这一竞争性更新申请将继续探索卡利司他汀在高血压中的作用。卡利司他汀最初是在我们的实验室发现的，是一种新的血浆丝氨酸蛋白酶抑制剂——组织钾化钾素结合蛋白。在目前的资助期内，出现了许多重要的发现，支持卡利司他汀在血压和血管生物学调节中起作用的假设。我们发现，卡利司他汀是一种有效的血管扩张剂，可直接引起短暂性血压降低、孤立主动脉环血管松弛和灌注大鼠肾脏血管舒张。过表达卡利司他汀的转基因小鼠具有低血压作用，卡利司他汀的体细胞基因传递可引起自发性高血压大鼠血压的显著且持久的降低。kalllistatin可能调节血管细胞生长，其在球囊损伤大鼠动脉中的表达水平显著升高，外源性kalllistatin刺激原代培养血管平滑肌细胞的增殖。具体目的是：1)通过定点突变和结构域替换分析卡利司他汀对血管细胞增殖和血管舒张的结构和功能关系；2)鉴定、表征和克隆血管中新的卡司他汀结合蛋白；3)通过反义传递卡利司他汀基因和核酶抑制策略，分析卡利司他汀在球囊损伤大鼠动脉血管细胞增殖和迁移中的作用；4)在自发性高血压大鼠中研究卡利司他汀基因在血压调节中的作用；5)分析卡利司他汀基因的启动子区域，以及在选定的高血压人群、受影响的兄弟姐妹和家系中人类卡利司他汀基因与高血压的遗传连锁和关联。本研究将显著提高我们对卡利司他汀在血压调节和血管功能中的作用的认识，并可能为改进高血压和心血管疾病的检测和治疗提供新的工具和技术。

This competing renewal application will continue to explore the role of kallistatin in hypertension. Kallistatin was first discovered in our laboratory as tissue kallikrein-binding protein, a new plasma serine proteinase inhibitor. During the current funding period, many important findings have emerged in support of the hypothesis that kallistatin has a role in the regulation of blood pressure and vascular biology. We found that kallistatin is a potent vasodilator that directly causes a transient reduction of blood pressure, vasorelaxation in isolated aortic rings, and vasodilation of the renal vasculature in perfused rat kidney. Transgenic mice overexpressing kallistatin are hypotensive and somatic gene delivery of kallistatin caused a significant and prolonged reduction of blood pressure in spontaneously hypertensive rats. Kallistatin may regulate vascular cell growth, as its expression levels increase markedly in balloon-injured rat artery and exogenous kallistatin stimulates the proliferation of primary cultured vascular smooth muscle cells. The specific aims are: 1) to analyze structural and functional relationships of kallistatin on vascular cell proliferation and vasorelaxation by site-directed mutagenesis and domain substitutions; 2) To identify, characterize and clone new kallistatin-binding protein in blood vessels; 3) To analyze the role of kallistatin in vascular cell proliferation and migration with a balloon-injured rat artery model by antisense kallistatin gene delivery and by ribozyme inhibition strategy; 4) To study the role of kallistatin in blood pressure regulation by delivery of the kallistatin gene in spontaneously hypertensive rats, and 5) To analyze the promoter region of the kallistatin gene and genetic linkage and association between the human kallistatin gene and hypertension in selected hypertensive populations, affected siblings and family pedigrees. The proposed work could significantly advance our understanding of the role of kallistatin in blood pressure regulation and vascular function and may provide new tools and technologies for improved detection and treatment of hypertension and cardiovascular diseases.