Highly Selective Drug-Derived Fluorescent Probes for the Cannabinoid Receptor Type 1 (CB₁R)

The cannabinoid receptor type 1 (CB1R) is pivotal within the endocannabinoid system regulating various signaling cascades with effects in appetite regulation, pain perception, memory formation, and thermoregulation. Still, understanding of CB1R’s cellular signaling, distribution, and expression dynamics is very fragmentary. Real-time visualization of CB1R is crucial for addressing these questions. Selective drug-like CB1R ligands with a defined pharmacological profile were investigated for the construction of CB1R fluorescent probes using a reverse design-approach. A modular design concept with a diethyl glycine-based building block as the centerpiece allowed for the straightforward synthesis of novel probe candidates. Validated by computational docking studies, radioligand binding, and cAMP assay, this systematic approach allowed for the identification of novel pyrrole-based CB1R fluorescent probes. Application in fluorescence-based target-engagement studies and live cell imaging exemplify the great versatility of the tailored CB1R probes for investigating CB1R localization, trafficking, pharmacology, and its pathological implications.1型大麻素受体（cannabinoid receptor type 1, CB1R）是内源性大麻素系统的核心调控分子，可介导多种信号级联反应，参与食欲调控、痛觉感知、记忆形成及体温调节等生理过程。然而，目前学界对CB1R的细胞信号转导、组织分布及表达动态的认知仍较为零散。对CB1R进行实时可视化成像，是破解上述认知局限的关键途径。本研究采用反向设计策略，以具备明确药理学特性的类药物选择性CB1R配体为基础开发CB1R荧光探针。该策略以二乙基甘氨酸类结构单元为核心组件搭建模块化设计框架，可便捷合成新型探针候选分子。经计算机分子对接实验、放射性配体结合实验及环腺苷酸（cAMP）检测实验验证后，这套系统性方法成功筛选得到新型吡咯类CB1R荧光探针。将该定制化CB1R探针应用于基于荧光的靶点结合实验与活细胞成像，结果证实其可有效用于CB1R定位、受体转运、药理学特性及其病理关联的相关研究，充分展现出这类探针极佳的应用多功能性。