Dual-Acting Small Molecules: Subtype-Selective Cannabinoid Receptor 2 Agonist/Butyrylcholinesterase Inhibitor Hybrids Show Neuroprotection in an Alzheimer’s Disease Mouse Model

We present the synthesis and characterization of merged human butyrylcholinesterase (hBChE) inhibitor/cannabinoid receptor 2 (hCB2R) ligands for the treatment of neurodegeneration. In total, 15 benzimidazole carbamates were synthesized and tested for their inhibition of human cholinesterases, also with regard to their pseudoirreversible binding mode and affinity toward both cannabinoid receptors in radioligand binding studies. After evaluation in a calcium mobilization assay as well as a β-arrestin 2 (βarr2) recruitment assay, two compounds with balanced activities on both targets were tested for their immunomodulatory effect on microglia activation and regarding their pharmacokinetic properties and blood–brain barrier penetration. Compound 15d, containing a dimethyl carbamate motif, was further evaluated in vivo, showing prevention of Aβ25–35-induced learning impairments in a pharmacological mouse model of Alzheimer’s disease for both short- and long-term memory responses. Additional combination studies proved a synergic effect of BChE inhibition and CB2R activation in vivo.

本研究报道了用于治疗神经退行性疾病的融合型人类丁酰胆碱酯酶（human butyrylcholinesterase, hBChE）抑制剂/人类大麻素受体2（human cannabinoid receptor 2, hCB2R）配体的合成与表征。共计合成并测试了15种苯并咪唑氨基甲酸酯类化合物对人类胆碱酯酶的抑制活性，同时考察了其拟不可逆结合模式，以及在放射性配体结合实验中对两种大麻素受体的亲和力。经钙动员检测及β抑制蛋白2（β-arrestin 2, βarr2）募集实验评估后，选取两种对双靶点活性均衡的化合物，分别测试其对小胶质细胞活化的免疫调节作用、药代动力学特性与血脑屏障穿透能力。含有二甲基氨基甲酸酯结构基序的化合物15d被进一步开展体内评价，在淀粉样β肽25-35（Aβ25–35）诱导的阿尔茨海默病药理小鼠模型中，可改善短期及长期记忆损伤。额外开展的联合研究证实，体内BChE抑制与CB2R激活存在协同效应。