Optimized GIP analogs promote body weight lowering in mice through GIPR agonism not antagonism
Optimized GIP analogs promote body weight lowering in mice through GIPR agonism not antagonism
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DOI：
10.1016/j.molmet.2018.12.001
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发表时间：
2019-02-01
影响因子：
8.1
通讯作者：
Perez-Tilve, Diego
中科院分区：
文献类型：
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作者：
Mroz, Piotr A.;Finan, Brian;Perez-Tilve, Diego
目的：结构改进的GIP类似物的开发，以准确地确定是否GIP受体（GIPR）激动或拮抗作用降低肥胖mice.Methods体重：一系列肽为基础的GIP类似物，包括结构不同的激动剂和长效拮抗剂，产生和特点是在体外使用功能测定过表达的人类和小鼠衍生受体的细胞系统。这些类似物在DIO小鼠中在急性给药后对血糖控制的影响和在慢性给药后对体重和食物摄入的影响进行体内表征。采用配对饲养试验和间接量热法研究其减肥机理。用先天性Gipr-/-和Glp 1 r-/- DIO小鼠研究激动剂的选择性，并将药理学归因于GIPR.Results介导的效应：来自人GIP序列的非酰化Aib 2取代类似物在体外对人GIPR显示完全效力，在体外对小鼠GIPR显示轻微降低的效力，而在GLP-1 R没有交叉反应性。这些GIPR激动剂降低了野生型和Glp 1 r-/-小鼠的急性血糖，而这种作用在Gipr-/-小鼠中不存在，这证实了对GIPR的选择性。DIO小鼠的长期治疗导致在使用不同类似物的许多研究中适度但一致的剂量依赖性体重降低。体重降低的机制是由于食物摄入量的减少，而不是能量消耗，如配对喂养研究和间接热量测定评估所示。在DIO Glp-1 r-/-小鼠中保留了体重降低作用，而在DIO Gipr-/-小鼠中不存在。GIPR激动剂的体重降低功效用表现出更高小鼠GIPR效力的类似物、用增加的施用频率和用延长的作用持续时间的脂肪酰化肽增强。此外，脂肪酰化、N末端截短的GIP类似物显示对人和小鼠GIPR具有高体外拮抗效力，而对小鼠GLP-1 R或小鼠胰高血糖素受体（GcgR）没有交叉反应活性。这种酰化拮抗剂充分抑制GIP的急性作用，以改善DIO小鼠的葡萄糖耐量。用高剂量的这种酰化GIPR拮抗剂对DIO小鼠进行慢性治疗不会导致体重变化。此外，该酰化GIPR拮抗剂与利拉鲁肽（一种酰化GLP-1 R激动剂）联合给药DIO小鼠，相对于利拉鲁肽给药小鼠，未导致体重降低增加。然而，在GLP-1 R和GIPR的长效选择性单独激动剂的共同治疗后，DIO小鼠的体重降低明显增强，与先前的数据一致。我们的结论是，基于肽的GIPR激动剂，而不是基于肽的GIPR拮抗剂，适当优化受体选择性，跨物种活性和作用持续时间，始终降低DIO小鼠的体重，尽管相对于GLP-1 R激动剂具有中等功效。这些临床前啮齿动物药理学结果与最近的临床结果一致，提供了明确的证据，证明全身性GIPR激动作用而非拮抗作用有利于体重减轻。(C)2018作者由爱思唯尔有限公司出版。
Objective: Structurally-improved GIP analogs were developed to determine precisely whether GIP receptor (GIPR) agonism or antagonism lowers body weight in obese mice.Methods: A series of peptide-based GIP analogs, including structurally diverse agonists and a long-acting antagonist, were generated and characterized in vitro using functional assays in cell systems overexpressing human and mouse derived receptors. These analogs were characterized in vivo in DIO mice following acute dosing for effects on glycemic control, and following chronic dosing for effects on body weight and food intake. Pair-feeding studies and indirect calorimetry were used to survey the mechanism for body weight lowering. Congenital Gipr-/- and Glp1r-/- DIO mice were used to investigate the selectivity of the agonists and to ascribe the pharmacology to effects mediated by the GIPR.Results: Non-acylated, Aib2 substituted analogs derived from human GIP sequence showed full in vitro potency at human GIPR and subtly reduced in vitro potency at mouse GIPR without cross-reactivity at GLP-1R. These GIPR agonists lowered acute blood glucose in wild-type and Glp1r-/- mice, and this effect was absent in Gipr-/- mice, which confirmed selectivity towards GIPR. Chronic treatment of DIO mice resulted in modest yet consistent, dose-dependent decreased body weight across many studies with diverse analogs. The mechanism for body weight lowering is due to reductions in food intake, not energy expenditure, as suggested by pair-feeding studies and indirect calorimetry assessment. The weight lowering effect was preserved in DIO Glp-1r-/- mice and absent in DIO Gipr-/- mice. The body weight lowering efficacy of GIPR agonists was enhanced with analogs that exhibit higher mouse GIPR potency, with increased frequency of administration, and with fatty-acylated peptides of extended duration of action. Additionally, a fatty-acylated, N-terminally truncated GIP analog was shown to have high in vitro antagonism potency for human and mouse GIPR without cross-reactive activity at mouse GLP-1R or mouse glucagon receptor (GcgR). This acylated antagonist sufficiently inhibited the acute effects of GIP to improve glucose tolerance in DIO mice. Chronic treatment of DIO mice with high doses of this acylated GIPR antagonist did not result in body weight change. Further, co-treatment of this acylated GIPR antagonist with liraglutide, an acylated GLP-1R agonist, to DIO mice did not result in increased body weight lowering relative to liraglutide-treated mice. Enhanced body weight lowering in DIO mice was evident however following co-treatment of long-acting selective individual agonists for GLP-1R and GIPR, consistent with previous data.Conclusions: We conclude that peptide-based GIPR agonists, not peptide-based GIPR antagonists, that are suitably optimized for receptor selectivity, cross-species activity, and duration of action consistently lower body weight in DIO mice, although with moderate efficacy relative to GLP-1R agonists. These preclinical rodent pharmacology results, in accordance with recent clinical results, provide definitive proof that systemic GIPR agonism, not antagonism, is beneficial for body weight loss. (C) 2018 The Authors. Published by Elsevier GmbH.