Key Lab of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
Key Lab of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
J Ethnopharmacol. 2021 Apr 24;270:113872. doi: 10.1016/j.jep.2021.113872. Epub 2021 Jan 21.
Mu opioid receptor (MOR) is mainly a drug target for analgesia. Opioid-like agonists such as morphine have been clinically used for analgesia but have potential adverse effects. MOR antagonists have been demonstrated to alleviate these side effects. Plants (Carthamus tinctorius L, Cynanchum otophyllum C. K. Schneid., Coffea arabica L., Prinsepia utilis Royle and Lepidium meyenii Walp.) and Ganoderma fungi (Ganoderma hainanense J. D. Zhao, Ganoderma capense (Lloyd) Teng, Ganoderma cochlear (Blume et Nees) Bres., Ganoderma resinaceum Boud and Ganoderma applanatum (Pers.) Pat.) are traditional medicines with beneficial effects on immunoregulation, analgesia and the nervous system, but whether MORs are engaged in their effects remains unknown.
This work aimed to identify MOR ligands among compounds isolated from the above-mentioned 10 species, and to investigate selectivity against four opioid receptor subtypes. By analyzing the structure-activity relationship and off-target effects, we could provide a new direction for the future development of MOR drugs.
Four opioid receptor subtype models, including MOR, delta (DOR), kappa (KOR) and nop (NOR), were established with a label-free phenotypic dynamic mass redistribution assay to systematically profile the pharmacological properties of known ligands. Then, 82 natural compounds derived from the 10 species were screened against MOR to identify new ligands. The selectivity of the new ligands was characterized against the four subtypes, and off-target effects were also investigated on eight G protein-coupled receptors (GPCRs).
The pharmacological properties of known ligands on transfected HEK293T-MOR, HEK293-DOR, HEK293-KOR and HEK293-NOR cell lines were characterized. Seven compounds purified from Ganoderma cochlear (Blume et Nees) Bres. and Carthamus tinctorius L were MOR antagonists with micromolar potency. Among them, compound 35 showed the strongest antagonistic activity on MOR with an IC value of 10.0 ± 3.0 μM. To a certain extent, these seven new antagonists, exhibited antagonistic activity on the other opioid receptor subtypes, and they had almost no effect on other GPCRs, including CB1, CB2, M2 and beta2AR. Additionally, a compound from Lepidium meyenii Walp. displayed MOR agonistic activity.
The established screening models opened new avenues for the discovery and evaluation of opioid receptor ligand selectivity. Together, the novel MOR antagonists and agonists will enrich the inventory of MOR ligands and benefit related therapies.
μ 阿片受体（MOR）主要是一种用于镇痛的药物靶点。阿片样激动剂，如吗啡，已在临床上用于镇痛，但具有潜在的副作用。MOR 拮抗剂已被证明可以缓解这些副作用。植物（红花、徐长卿、咖啡、松口蘑和秘鲁玛咖）和灵芝真菌（海南灵芝、密纹灵芝、鹿角灵芝、赤芝和密纹赤芝）是具有免疫调节、镇痛和神经系统有益作用的传统药物，但它们是否涉及 MOR 仍不清楚。
本研究旨在从上述 10 种化合物中鉴定出 MOR 配体，并研究其对四种阿片受体亚型的选择性。通过分析结构-活性关系和非靶点效应，为未来 MOR 药物的发展提供新的方向。
采用无标记表型动态质量重分布测定法建立了四个阿片受体亚型模型，包括 MOR、δ（DOR）、κ（KOR）和 nop（NOR），以系统地分析已知配体的药理学特性。然后，从 10 种物种中筛选了 82 种天然化合物来鉴定新的配体。对新配体的选择性进行了表征，对 8 种 G 蛋白偶联受体（GPCR）也进行了非靶点效应研究。
对转染的 HEK293T-MOR、HEK293-DOR、HEK293-KOR 和 HEK293-NOR 细胞系中已知配体的药理学特性进行了表征。从灵芝（Blume et Nees）和红花中分离得到的 7 种化合物是 MOR 拮抗剂，具有微摩尔效力。其中，化合物 35 对 MOR 的拮抗活性最强，IC 值为 10.0±3.0μM。在一定程度上，这 7 种新的拮抗剂对其他阿片受体亚型也表现出拮抗活性，对其他 GPCR，包括 CB1、CB2、M2 和β2AR，几乎没有影响。此外，一种来自秘鲁玛咖的化合物显示出 MOR 激动剂活性。
所建立的筛选模型为发现和评估阿片受体配体选择性开辟了新途径。新型 MOR 拮抗剂和激动剂的发现将丰富 MOR 配体的库存，并有益于相关治疗。
