Comparable Initial Engagement of Intracellular Signaling Pathways by Parathyroid Hormone Receptor Ligands Teriparatide, Abaloparatide, and Long-Acting PTH.
Comparable Initial Engagement of Intracellular Signaling Pathways by Parathyroid Hormone Receptor Ligands Teriparatide, Abaloparatide, and Long-Acting PTH.
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作者：
Sato T;Verma S;Khatri A;Dean T;Goransson O;Gardella TJ;Wein MN
甲状旁腺激素的多种类似物均与 PTH/PTHrP 受体 PTH1R 结合，用于治疗骨质疏松症和甲状旁腺功能减退症患者。尽管阿巴洛帕肽、特立帕肽 (hPTH 1-34 [TPTD]) 和长效 PTH (LA-PTH) 等配体在骨骼和矿物质代谢终点方面显示出不同的生物学效应，但这些临床重要差异的机制基础仍不完全清楚。先前的工作揭示了不同 PTH1R 肽配体之间的差异信号传导动力学和受体构象接合。然而，这种急性膜近端差异是否会转化为下游信号输出的差异仍有待确定。在这里，我们直接比较了 hPTH (1-34)、abaloparatide 和 LA-PTH 在多个基于细胞的 PTH1R 信号转导测定中的短期效应。在使用的时间点和配体浓度下，这三种配体在受体内化、β-抑制蛋白募集、细胞内钙刺激和 cAMP 生成水平上没有观察到显着差异。然而，在洗脱研究中，abaloparatide 显示出显着更快的 PTH1R 回收。在 PTH1R 刺激的 cAMP 生成下游，蛋白激酶 A 通过影响盐诱导激酶 (SIK) 及其底物来调节基因表达。与这些配体对 cAMP 生成没有差异一致，我们观察到 hPTH (1-34)、abaloparatide 和 LA-PTH 对 SIK2 磷酸化、SIK 底物去磷酸化和下游基因表达变化显示出相当的影响。总而言之，这些结果表明这些 PTH1R 肽激动剂以相当的程度参与下游细胞内信号传导途径。在临床前和临床模型中观察到的体内差异可能与药代动力学因素有关。我们目前的体外系统也可能不足以完美匹配体内骨真正靶细胞中 PTH1R 信号传导的复杂性。 © 2020 美国骨与矿物质研究学会 © 2020 作者。 JBMR Plus 由 Wiley periodicals LLC 出版。代表美国骨与矿物质研究学会。
Multiple analogs of parathyroid hormone, all of which bind to the PTH/PTHrP receptor PTH1R, are used for patients with osteoporosis and hypoparathyroidism. Although ligands such as abaloparatide, teriparatide (hPTH 1‐34 [TPTD]), and long‐acting PTH (LA‐PTH) show distinct biologic effects with respect to skeletal and mineral metabolism endpoints, the mechanistic basis for these clinically‐important differences remains incompletely understood. Previous work has revealed that differential signaling kinetics and receptor conformation engagement between different PTH1R peptide ligands. However, whether such acute membrane proximal differences translate into differences in downstream signaling output remains to be determined. Here, we directly compared short‐term effects of hPTH (1‐34), abaloparatide, and LA‐PTH in multiple cell‐based PTH1R signaling assays. At the time points and ligand concentrations utilized, no significant differences were observed between these three ligands at the level of receptor internalization, β‐arrestin recruitment, intracellular calcium stimulation, and cAMP generation. However, abaloparatide showed significantly quicker PTH1R recycling in washout studies. Downstream of PTH1R‐stimulated cAMP generation, protein kinase A regulates gene expression via effects on salt inducible kinases (SIKs) and their substrates. Consistent with no differences between these ligands on cAMP generation, we observed that hPTH (1‐34), abaloparatide, and LA‐PTH showed comparable effects on SIK2 phosphorylation, SIK substrate dephosphorylation, and downstream gene expression changes. Taken together, these results indicate that these PTH1R peptide agonists engage downstream intracellular signaling pathways to a comparable degree. It is possible that differences observed in vivo in preclinical and clinical models may be related to pharmacokinetic factors. It is also possible that our current in vitro systems are insufficient to perfectly match the complexities of PTH1R signaling in bona fide target cells in bone in vivo. © 2020 American Society for Bone and Mineral Research © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.