C1 INHIBITOR GENE AND HEREDITARY ANGIONEUROTIC EDEMA

描述（改编自研究者摘要）：C1抑制剂（C1 INH）是一种 丝氨酸蛋白酶抑制剂（丝氨酸蛋白酶抑制剂），调节经典的 补体途径和接触（激肽产生）系统的失活 C1 r、C1 s、血浆激肽释放酶和因子XII。C1 INH杂合性 C1 INH蛋白的缺乏或表达功能障碍导致 遗传性血管性水肿（HAE）。在第一个目标中，HAE的动物模型将是 利用基因靶向技术开发的。我们假设C1 INH-/-小鼠 将不能存活，C1 NH +/-小鼠将发生血管性水肿。测试 假设血管性水肿是通过接触系统激活介导的，缺乏 小鼠将用具有改变的靶标的重组C1 INH突变体重建 蛋白酶特异性，并将与缓激肽受体2（Bk 2 R）交配 和C2缺陷小鼠。为了验证抑制 缓激肽将干扰症状，HAE小鼠将用 Bk 2 R拮抗剂。雄激素在血管性水肿中的作用机制也将 被分析。为了验证接触系统在 感染性休克的发病机制，C1 INH +/-小鼠对内毒素的易感性 冲击将被确定。具有选择性抑制作用的C1 INH蛋白的输注 活动将确定补充和联络系统的作用。的 第二个目标是结构-功能分析。测试 假设稳定的复合物的形成需要大量的插入， 反应中心环（RCL）转化为β折叠A，RCL突变体和 将检查改变片材A的稳定性。为了验证这个假设， RCL内外的位点决定靶蛋白酶特异性，P2 α 1-抗胰蛋白酶：C1 INH的突变体、远端环突变体和非RCL突变体 将测试嵌合体。为了验证氨基末端截短的 C1 INH更有效地抑制表面相关的蛋白酶，其抑制蛋白酶的能力， 抑制免疫复合物介导的补体激活， 分子量激肽原（HK）结合的激肽释放酶和表面结合因子XIIa 将被审查。将C1 INH与其他结构进行比较， 丝氨酸蛋白酶抑制剂，重组截短的C1 INH将被结晶。除了 C1 INH的生物学作用的定义及其功能的表征， 这些研究也可能导致HAE和其他疾病的治疗改善， 补体或接触系统的激活起作用。

DESCRIPTION (Adapted from investigator's abstract): C1 inhibitor (C1INH) is a serine proteinase inhibitor (serpin) that regulates activation of the classical complement pathway and the contact (kinin-generating) systems by inactivation of C1r, C1s, plasma kallikrein and factor XII. Heterozygosity for C1INH deficiency or for expression of a dysfunctional C1INH protein results in hereditary angioedema (HAE). In the first Aim, an animal model for HAE will be developed using gene targeting technology. We hypothesize that C1INH-/-mice will not survive and that C1NH +/- mice will develop angioedema. To test the hypothesis that angioedema is mediated via contact system activation, deficient mice will be reconstituted with recombinant C1INH mutants with altered target proteinase specificities, and will be mated with bradykinin receptor 2 (Bk2R) and with C2 deficient mice. To test the hypothesis that inhibition of bradykinin will interfere with symptoms, the HAE mice will the treated with Bk2R antagonists. The mechanism of action of androgens in angioedema also will be analyzed. To test the hypothesis that the contact system plays a role in the pathogenesis of septic shock, the susceptibility of C1INH +/- mice to endotoxin shock will be determined. Infusions of C1INH proteins with selective inhibitory activities will define the roles of the complement and contact systems. The second Aim is directed toward structure-function analyses. To test the hypothesis that stable complex formation requires extensive insertion of the reactive center loop (RCL) into beta sheet A, RCL mutants and mutants that alter the stability of sheet A will be examined. To test the hypothesis that sites within and outside the RCL determine target protease specificity, P2 mutants, distal loop mutants, and non-RCL mutants in alpha1-antitrypsin:C1INH chimeras will be tested. To test the hypothesis that amino terminal-truncated C1INH more efficiently inhibits surface associated proteases, its ability to inhibit immune complex-mediated complement activation, and inactivate high molecular weight kininogen (HK)-bound kallikrein and surface-bound factor XIIa will be examined. To compare and contrast the structure of C1INH with other serpins, recombinant truncated C1INH will be crystallized. In addition to definition of the biologic roles of C1INH and characterization of its function, these studies also may lead to improved therapy of HAE and of other diseases in which activation of the complement or contact systems plays a role.