Institute on Aging and Brain Disorders, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China.
Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
FASEB J. 2020 Aug;34(8):10920-10930. doi: 10.1096/fj.201903093R. Epub 2020 Jul 1.
Cannabinoids exert therapeutic effects on several diseases such as chronic pain and startle disease by targeting glycine receptors (GlyRs). Our previous studies have shown that cannabinoids target a serine residue at position 296 in the third transmembrane helix of the α1/α3 GlyR. This site is located on the outside of the ion channel protein at the lipid interface where the cholesterol concentrates. However, whether membrane cholesterol regulates cannabinoid-GlyR interaction remains unknown. Here, we show that GlyRs are closely associated with cholesterol/caveolin-rich domains at subcellular levels. Membrane cholesterol reduction significantly inhibits cannabinoid potentiation of glycine-activated currents in cultured spinal neurons and in HEK 293T cells expressing α1/α3 GlyRs. Such inhibition is fully rescued by cholesterol replenishment in a concentration-dependent manner. Molecular docking calculations further reveal that cholesterol regulates cannabinoid enhancement of GlyR function through both direct and indirect mechanisms. Taken together, these findings suggest that cholesterol is critical for the cannabinoid-GlyR interaction in the cell membrane.
大麻素通过靶向甘氨酸受体 (GlyRs) 对多种疾病发挥治疗作用，如慢性疼痛和惊吓症。我们之前的研究表明，大麻素靶向 α1/α3 GlyR 第三跨膜螺旋中位置 296 的丝氨酸残基。该位点位于离子通道蛋白的脂质界面外侧，胆固醇集中于此。然而，膜胆固醇是否调节大麻素-GlyR 相互作用尚不清楚。在这里，我们表明 GlyRs 在亚细胞水平上与富含胆固醇/窖蛋白的区域密切相关。膜胆固醇减少显著抑制大麻素增强培养的脊髓神经元和表达 α1/α3 GlyRs 的 HEK 293T 细胞中甘氨酸激活电流。这种抑制作用可以通过胆固醇补充以浓度依赖的方式完全挽救。分子对接计算进一步表明，胆固醇通过直接和间接机制调节大麻素对 GlyR 功能的增强。总之，这些发现表明胆固醇对于细胞膜中大麻素-GlyR 相互作用至关重要。
