Department of Integrative Structural and Computational Biology , The Scripps Research Institute , La Jolla , California 92037 , United States.
J Med Chem. 2019 Feb 28;62(4):2008-2023. doi: 10.1021/acs.jmedchem.8b01573. Epub 2019 Feb 7.
Pioglitazone (Pio) is a Food and Drug Administration-approved drug for type-2 diabetes that binds and activates the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ), yet it remains unclear how in vivo Pio metabolites affect PPARγ structure and function. Here, we present a structure-function comparison of Pio and its most abundant in vivo metabolite, 1-hydroxypioglitazone (PioOH). PioOH displayed a lower binding affinity and reduced potency in co-regulator recruitment assays. X-ray crystallography and molecular docking analysis of PioOH-bound PPARγ ligand-binding domain revealed an altered hydrogen bonding network, including the formation of water-mediated bonds, which could underlie its altered biochemical phenotype. NMR spectroscopy and hydrogen/deuterium exchange mass spectrometry analysis coupled to activity assays revealed that PioOH better stabilizes the PPARγ activation function-2 (AF-2) co-activator binding surface and better enhances co-activator binding, affording slightly better transcriptional efficacy. These results indicating that Pio hydroxylation affects its potency and efficacy as a PPARγ agonist contributes to our understanding of PPARγ-drug metabolite interactions.
吡格列酮（Pio）是一种经美国食品和药物管理局批准的用于 2 型糖尿病的药物，它能与核受体过氧化物酶体增殖物激活受体γ（PPARγ）结合并激活该受体，但尚不清楚体内吡格列酮代谢物如何影响 PPARγ 的结构和功能。在这里，我们对吡格列酮及其最丰富的体内代谢物 1-羟基吡格列酮（PioOH）进行了结构-功能比较。PioOH 在共调节剂募集测定中显示出较低的结合亲和力和降低的效力。PioOH 结合的 PPARγ 配体结合域的 X 射线晶体学和分子对接分析显示出改变的氢键网络，包括形成水介导的键，这可能是其改变的生化表型的基础。NMR 光谱和氢/氘交换质谱分析结合活性测定表明，PioOH 更好地稳定了 PPARγ 激活功能-2（AF-2）共激活剂结合表面，并更好地增强了共激活剂结合，从而提供了稍好的转录功效。这些结果表明，吡格列酮羟化作用影响其作为 PPARγ 激动剂的效力和功效，有助于我们理解 PPARγ-药物代谢物相互作用。
