Cheloha Ross W, Chen Bingming, Kumar Niyanta N, Watanabe Tomoyuki, Thorne Robert G, Li Lingjun, Gardella Thomas J, Gellman Samuel H
Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
School of Pharmacy, University of Wisconsin-Madison , 777 Highland Avenue, Madison, Wisconsin 53705, United States.
J Med Chem. 2017 Nov 9;60(21):8816-8833. doi: 10.1021/acs.jmedchem.7b00876. Epub 2017 Oct 24.
The parathyroid hormone receptor 1 (PTHR1) is a member of the B-family of GPCRs; these receptors are activated by long polypeptide hormones and constitute targets of drug development efforts. Parathyroid hormone (PTH, 84 residues) and PTH-related protein (PTHrP, 141 residues) are natural agonists of PTHR1, and an N-terminal fragment of PTH, PTH(1-34), is used clinically to treat osteoporosis. Conventional peptides in the 20-40-mer length range are rapidly degraded by proteases, which may limit their biomedical utility. We have used the PTHR1-ligand system to explore the impact of broadly distributed replacement of α-amino acid residues with β-amino acid residues on susceptibility to proteolysis and agonist activity. This effort led us to identify new PTHR1 agonists that contain α → β replacements throughout their sequences, manifest potent agonist activity in cellular assays, and display remarkable resistance to proteolysis, in cases remaining active after extended exposure to simulated gastric fluid. The strategy we have employed suggests a path toward identifying protease-resistant agonists of other B-family GPCRs.
甲状旁腺激素受体1（PTHR1）是G蛋白偶联受体B家族的成员；这些受体由长多肽激素激活，是药物研发的靶点。甲状旁腺激素（PTH，84个氨基酸残基）和甲状旁腺激素相关蛋白（PTHrP，141个氨基酸残基）是PTHR1的天然激动剂，PTH的N端片段PTH(1-34)在临床上用于治疗骨质疏松症。长度在20 - 40个氨基酸残基范围内的传统肽会被蛋白酶迅速降解，这可能会限制它们的生物医学应用。我们利用PTHR1 - 配体系统，探索广泛分布的α - 氨基酸残基被β - 氨基酸残基取代对蛋白水解敏感性和激动剂活性的影响。这项工作使我们鉴定出了新的PTHR1激动剂，它们在整个序列中都含有α→β取代，在细胞试验中表现出强大的激动剂活性，并且对蛋白水解具有显著抗性，在某些情况下，长时间暴露于模拟胃液后仍保持活性。我们采用的策略为鉴定其他B家族G蛋白偶联受体的蛋白酶抗性激动剂指明了一条道路。
