Department of Chemistry, New York University, New York, New York 10003, United States.
Liver Disease Lab, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain.
J Am Chem Soc. 2023 Oct 11;145(40):21841-21850. doi: 10.1021/jacs.3c05704. Epub 2023 Oct 2.
Magnesium(II) plays catalytic, structural, regulatory, and signaling roles in living organisms. Abnormal levels of this metal have been associated with numerous pathologies, including cardiovascular disease, diabetes, metabolic syndrome, immunodeficiency, cancer, and, most recently, liver pathologies affecting humans. The role of Mg in the pathophysiology of liver disease, however, has been occluded by concomitant changes in concentration of interfering divalent cations, such as Ca, which complicates the interpretation of experiments conducted with existing molecular Mg indicators. Herein, we introduce a new quinoline-based fluorescent sensor, MagZet1, that displays a shift in its excitation and emission wavelengths, affording ratiometric detection of cellular Mg by both fluorescence microscopy and flow cytometry. The new sensor binds the target metal with a submillimolar dissociation constant─well suited for detection of changes in free Mg in cells─and displays a 10-fold selectivity against Ca. Furthermore, the fluorescence ratio is insensitive to changes in pH in the physiological range, providing an overall superior performance over existing indicators. We provide insights into the metal selectivity profile of the new sensor based on computational modeling, and we apply it to shed light on a decrease in cytosolic free Mg and altered expression of metal transporters in cellular models of drug-induced liver injury caused by acetaminophen overdose.
镁（II）在生物体中发挥催化、结构、调节和信号作用。这种金属的异常水平与许多病理学有关，包括心血管疾病、糖尿病、代谢综合征、免疫缺陷、癌症，以及最近与人类肝脏疾病有关的病理学。然而，由于共存的干扰二价阳离子（如 Ca）浓度的变化，镁在肝病病理生理学中的作用被掩盖了，这使得用现有的分子镁指示剂进行的实验的解释变得复杂。在这里，我们引入了一种新的基于喹啉的荧光传感器 MagZet1，它显示出其激发和发射波长的移动，通过荧光显微镜和流式细胞术实现了对细胞内镁的比率检测。新传感器与目标金属的解离常数为亚毫摩尔，非常适合检测细胞内游离镁的变化，并且对 Ca 的选择性高 10 倍。此外，荧光比对生理范围内的 pH 变化不敏感，提供了优于现有指示剂的整体性能。我们基于计算建模提供了对新传感器的金属选择性概况的深入了解，并将其应用于阐明在对乙酰氨基酚过量引起的药物诱导肝损伤的细胞模型中，细胞质游离镁减少和金属转运蛋白表达改变的情况。
