Peptide and nonpeptide antagonist interaction with constitutively active human AT1 receptors
Peptide and nonpeptide antagonist interaction with constitutively active human AT1 receptors
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DOI：
10.1016/s0006-2952(03)00072-8
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发表时间：
2003-04-15
影响因子：
5.8
通讯作者：
Vauquelin, G
中科院分区：
文献类型：
--
作者：
Le, MT;Vanderheyden, PML;Vauquelin, G
野生型人AT受体（WT-AT(1)）和Asn（111）被甘氨酸（N111G）、丙氨酸（N111A）和丝氨酸（N111S）取代，或Asp（281）被丙氨酸（D281A）取代，或N111G和D281A替代组合的突变受体在ho - k1细胞中短暂表达。虽然联苯四唑化合物坎地沙坦解离缓慢，表现为WT-AT的不可克服的拮抗剂(1)，但它解离迅速，仅在表达N111G的细胞中产生血管紧张素Ang II和- iv对肌醇磷酸（IP）积累的剂量反应曲线向右移动。[H-3]坎地沙坦竞争结合对WT-AT(1)和突变受体产生的相关联苯四唑效序相同，即坎地沙坦> EXP3174 > irbesartan >氯沙坦。WT-AT(1)和D281A的亲和度相等，所有asnii I突变体的亲和度低40- 400倍。突变不影响肽拮抗剂[Sar(1)Ile(8)]Ang II （SARILE）的亲和力。WT-AT细胞(1)的基础IP积累不受任何联苯四唑拮抗剂的影响，并且SARILE使其增加到最大Ang II刺激的19%。表达Asn（111）突变受体的细胞的基础IP积累更高。对于N111G，在长期（18小时）暴露后，所有联苯四唑都部分抑制了这种积累。在这些细胞中，SARILE产生与Ang II相同的最大刺激。Asn（111）突变的AT受体被认为模拟野生型受体的预激活状态，比较这种突变受体的配体的功效和亲和力有助于区分部分（SARILE）和逆（联苯四唑）激动剂和真正的拮抗剂。(C) 2003爱思唯尔科学有限公司版权所有。
Wild type human AT, receptors (WT-AT(1)) and mutant receptors, in which Asn(111) was replaced by glycine (N111G), alanine (N111A) and serine (N111S), or in which Asp(281) was replaced by alanine (D281A) or in which N111G and D281A replacements were combined, were transiently expressed in CHO-K1 cells. While the biphenyltetrazole compound candesartan dissociated slowly and behaved as an insurmountable antagonist for WT-AT(1), it dissociated swiftly and only produced a rightward shift of the angiotensin Ang II- and -IV dose-response curves for inositol phosphate (IP) accumulation in cells expressing N111G. [H-3]candesartan competition binding yielded the same potency order of the related biphenyltetrazoles for WT-AT(1) and mutated receptors, i.e. candesartan > EXP3174 > irbesartan > losartan. Affinities were equal for WT-AT(1) and D281A and 40- to 400-fold lower for all AsnI I I mutants. Mutations did not affect the affinity of the peptide antagonist [Sar(1)Ile(8)]Ang II (SARILE). Basal IP accumulation in cells with WT-AT(1) was not affected by any biphenyltetrazole antagonists and was increased by SARILE to 19% of the maximal Ang II stimulation. Basal IP accumulation was higher for cells expressing the Asn(111)-mutated receptors. For N111G, this accumulation was partially inhibited by all the biphenyltetrazoles upon long-term (18 hr) exposure. In these cells SARILE produced the same maximal stimulation as Ang II. Asn(111)-mutated AT, receptors are thought to mimic the pre-activated state of the wild type receptor and comparing the efficacy and affinity of ligands for such mutated receptors facilitate the distinction of partial (SARILE) and inverse (biphenyltetrazoles) agonists from true antagonists. (C) 2003 Elsevier Science Inc. All rights reserved.