The histamine H₃ receptor (H₃R) represents a highly attractive drug target for the treatment of various central nervous system disorders, but the discovery of novel H₃R targeting compounds relies on the assessment of highly amplified intracellular signaling events that do not only reflect H₃R modulation and carry the risk of high false-positive and -negative screening rates. To address these limitations, we designed an intramolecular H₃R biosensor based on the principle of bioluminescence resonance energy transfer (BRET) that reports the receptor’s real-time conformational dynamics and provides an advanced tool to screen for both H₃R agonists and inverse agonists in a live cell screening-compatible assay format. This conformational G-protein-coupled receptor (GPCR) sensor allowed us to characterize the pharmacological properties of known and new H₃ receptor ligands with unprecedented accuracy. Interestingly, we found that one newly developed H₃ receptor ligand possesses even stronger inverse agonistic activity than reference H₃R inverse agonists including the current gold standard pitolisant. Taken together, we describe here the design and validation of the first screening-compatible H₃R conformational biosensor that will aid in the discovery of novel H₃R ligands and can be employed to gain deeper insights into the (in-)activation mechanism of this highly attractive drug target.

中文翻译：

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构象组胺H3受体生物传感器的开发，用于激动剂和逆激动剂的同步筛选。

组胺H ₃受体（H ₃ R）代表了用于治疗各种中枢神经系统疾病的极具吸引力的药物靶标，但是新型靶向H ₃ R的化合物的发现依赖于高度扩增的细胞内信号转导事件的评估，这不仅反映H ₃ R调制，并具有高假阳性和阴性筛查率的风险。为了解决这些局限性，我们基于生物发光共振能量转移（BRET）原理设计了分子内H ₃ R生物传感器，该传感器报告受体的实时构象动力学，并提供了一种用于筛选H ₃的先进工具活细胞筛选兼容测定形式的R激动剂和反向激动剂。这种构象的G蛋白偶联受体（GPCR）传感器使我们能够以前所未有的准确性表征已知和新的H ₃受体配体的药理特性。有趣的是，我们发现一种新开发的H ₃受体配体具有比参考H ₃ R反向激动剂（包括当前的金标准pitolisant）更强的反向激动活性。两者合计，我们在这里描述了第一个筛选兼容的H ₃ R构象生物传感器的设计和验证，这将有助于发现新型H ₃R配体可以用于深入了解这种高度吸引人的药物靶标的（激活）机制。