Rønnekleiv Oline K, Fang Yuan, Zhang Chunguang, Nestor Casey C, Mao Peizhong, Kelly Martin J
Department of Physiology and Pharmacology (O.K.R., Y.F., C.Z., C.CN., P.M., M.J.K.), Oregon Health and Science University, Portland, Oregon 97239; and Division of Neuroscience (O.K.R., P.M., M.J.K.), Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon 97006.
Mol Endocrinol. 2014 Aug;28(8):1362-80. doi: 10.1210/me.2014-1103. Epub 2014 Jun 16.
The hypothalamic arcuate nucleus controls many critical homeostatic functions including energy homeostasis, reproduction, and motivated behavior. Although G protein-coupled receptors (GPCRs) are involved in the regulation of these functions, relatively few of the GPCRs have been identified specifically within the arcuate nucleus. Here, using TaqMan low-density arrays we quantified the mRNA expression of nonolfactory GPCRs in mouse arcuate nucleus. An unprecedented number of GPCRs (total of 292) were found to be expressed, of which 183 were known and 109 were orphan GPCRs. The known GPCR genes expressed were classified into several functional clusters including hormone/neurotransmitter, growth factor, angiogenesis and vasoactivity, inflammation and immune system, and lipid messenger receptors. The plethora of orphan genes expressed in the arcuate nucleus were classified into 5 structure-related classes including class A (rhodopsin-like), class B (adhesion), class C (other GPCRs), nonsignaling 7-transmembrane chemokine-binding proteins, and other 7-transmembrane proteins. Therefore, for the first time, we provide a quantitative estimate of the numerous GPCRs expressed in the hypothalamic arcuate nucleus. Finally, as proof of principle, we documented the expression and function of one of these receptor genes, the glucagon-like peptide 1 receptor (Glp1r), which was highly expressed in the arcuate nucleus. Single-cell RT-PCR revealed that Glp1r mRNA was localized in proopiomelanocortin neurons, and using whole-cell recording we found that the glucagon-like peptide 1-selective agonist exendin-4 robustly excited proopiomelanocortin neurons. Thus, the quantitative GPCR data emphasize the complexity of the hypothalamic arcuate nucleus and furthermore provide a valuable resource for future neuroendocrine/endocrine-related experiments.
下丘脑弓状核控制着许多关键的稳态功能，包括能量稳态、生殖和动机行为。尽管G蛋白偶联受体（GPCRs）参与这些功能的调节，但在弓状核内特异性鉴定出的GPCRs相对较少。在此，我们使用TaqMan低密度芯片对小鼠弓状核中非嗅觉GPCRs的mRNA表达进行了定量分析。我们发现有数量空前的GPCRs（总共292个）表达，其中183个是已知的，109个是孤儿GPCRs。所表达的已知GPCR基因被分为几个功能簇，包括激素/神经递质、生长因子、血管生成和血管活性、炎症和免疫系统以及脂质信使受体。在弓状核中表达的大量孤儿基因被分为5个与结构相关的类别，包括A类（视紫红质样）、B类（粘附）、C类（其他GPCRs）、无信号7跨膜趋化因子结合蛋白和其他7跨膜蛋白。因此，我们首次对下丘脑弓状核中表达的众多GPCRs进行了定量评估。最后，作为原理验证，我们记录了其中一个受体基因胰高血糖素样肽1受体（Glp1r）的表达和功能，该基因在弓状核中高度表达。单细胞RT-PCR显示Glp1r mRNA定位于阿黑皮素原神经元中，并且通过全细胞记录我们发现胰高血糖素样肽1选择性激动剂艾塞那肽-4强烈兴奋阿黑皮素原神经元。因此，定量的GPCR数据强调了下丘脑弓状核的复杂性，并且还为未来的神经内分泌/内分泌相关实验提供了宝贵的资源。
