Pharmacological evidence for transactivation within melatonin MT2 and serotonin 5-HT2C receptor heteromers in mouse brain.
Pharmacological evidence for transactivation within melatonin MT2 and serotonin 5-HT2C receptor heteromers in mouse brain.
复制标题
小鼠大脑中褪黑素 MT2 和血清素 5-HT2C 受体异聚体反式激活的药理学证据。
DOI：
10.1096/fj.202000305r
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Gerbier R
中科院分区：
文献类型：
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作者：
Gerbier R
G蛋白偶联受体与异二聚体复合物的结合已经在体外报道了50多种受体对，但在体内的功能验证仍然是一个挑战。我们最近的体外研究确定了Gi偶联褪黑激素mt2受体和Gq偶联5 -羟色胺5 - HT2C受体组成的异聚体的功能指纹图谱，其中褪黑激素通过5 - HT2C激活磷脂酶C （PLC）。在这里，我们在老鼠大脑中发现了这个功能性指纹。gq蛋白激活通过[35S] gtp - γ - s掺入，然后gq免疫沉淀，PLC激活通过测定先前接受褪黑激素治疗的动物脑裂解物中的肌醇磷酸水平来检测。褪黑素浓度依赖性激活下丘脑和小脑中的gq蛋白和PLC，但在皮层中没有。这些效应被5‐ht2c受体特异性逆激动剂SB‐243213抑制，并且在mt2和5‐ht2c敲除小鼠中不存在，这完全再现了先前的体外数据，并表明MT2/5‐HT2Cheteromers参与其中。抗抑郁药阿戈美拉汀单独使用时与褪黑激素效果相似，但由于其5 - ht2拮抗成分，阻断了褪黑激素促进的gq激活。总之，我们为小鼠大脑中MT2/5‐ht2异构体复合物的存在提供了强有力的功能证据。这些异构体可能参与了阿戈美拉汀的体内作用。
Association of G protein‐coupled receptors into heterodimeric complexes has been reported for over 50 receptor pairs in vitro but functional in vivo validation remains a challenge. Our recent in vitro studies defined the functional fingerprint of heteromers composed of Gi‐coupled melatonin MT2receptors and Gq‐coupled serotonin 5‐HT2Creceptors, in which melatonin transactivates phospholipase C (PLC) through 5‐HT2C. Here, we identified this functional fingerprint in the mouse brain. Gqprotein activation was probed by [35S]GTPγS incorporation followed by Gqimmunoprecipitation, and PLC activation by determining the inositol phosphate levels in brain lysates of animals previously treated with melatonin. Melatonin concentration‐dependently activated Gqproteins and PLC in the hypothalamus and cerebellum but not in cortex. These effects were inhibited by the 5‐HT2Creceptor‐specific inverse agonist SB‐243213, and were absent in MT2and 5‐HT2Cknockout mice, fully recapitulating previous in vitro data and indicating the involvement of MT2/5‐HT2Cheteromers. The antidepressant agomelatine had a similar effect than melatonin when applied alone but blocked the melatonin‐promoted Gqactivation due to its 5‐HT2Cantagonistic component. Collectively, we provide strong functional evidence for the existence of MT2/5‐HT2Cheteromeric complexes in mouse brain. These heteromers might participate in the in vivo effects of agomelatine.