An Inhibitory Antibody against Dipeptidyl Peptidase IV Improves Glucose Tolerance in Vivo
An Inhibitory Antibody against Dipeptidyl Peptidase IV Improves Glucose Tolerance in Vivo
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DOI：
10.1074/jbc.m112.396317
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发表时间：
2013-01-11
影响因子：
4.8
通讯作者：
Wang, Zhulun
中科院分区：
文献类型：
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作者：
Tang, Jie;Majeti, Jiangwen;Wang, Zhulun
二肽基肽酶IV(DPP-IV)降解胰升糖素样肽1(GLP-1)。小分子DPP-IV抑制剂已被用于治疗2型糖尿病，以改善糖耐量。然而，每一种上市的小分子药物在疗效和副作用方面都有自己的局限性。为了寻找抑制DPP-IV活性的替代策略，我们制备了一组紧密结合的抑制性小鼠抗大鼠DPP-IV的单抗。在体外试验中，这些单抗部分抑制了纯化酶和大鼠血浆中GLP-1的切割活性。为了了解部分抑制作用，我们解决了其中一个单抗Fabs(Ab1)与大鼠DPP-IV络合物的共晶结构。虽然AB1不结合在活性部位，但它部分阻止了侧面开口，这阻止了GLP-1等大底物进入活性部位，但不能阻止小分子如西格列普汀。当在体内测试AB1时，在大鼠的口服葡萄糖耐量测试中，它降低了血糖，增加了血浆GLP-1浓度。我们共同证明了在糖尿病大鼠模型中使用单抗抑制DPP-IV活性和改善糖耐量的可行性。
Dipeptidyl peptidase IV (DPP-IV) degrades the incretin hormone glucagon-like peptide 1 (GLP-1). Small molecule DPP-IV inhibitors have been used as treatments for type 2 diabetes to improve glucose tolerance. However, each of the marketed small molecule drugs has its own limitation in terms of efficacy and side effects. To search for an alternative strategy of inhibiting DPP-IV activity, we generated a panel of tight binding inhibitory mouse monoclonal antibodies (mAbs) against rat DPP-IV. When tested in vitro, these mAbs partially inhibited the GLP-1 cleavage activity of purified enzyme and rat plasma. To understand the partial inhibition, we solved the co-crystal structure of one of the mAb Fabs (Ab1) in complex with rat DPP-IV. Although Ab1 does not bind at the active site, it partially blocks the side opening, which prevents the large substrates such as GLP-1 from accessing the active site, but not small molecules such as sitagliptin. When Ab1 was tested in vivo, it reduced plasma glucose and increased plasma GLP-1 concentration during an oral glucose tolerance test in rats. Together, we demonstrated the feasibility of using mAbs to inhibit DPP-IV activity and to improve glucose tolerance in a diabetic rat model.