METHODS: Mice expressing Cre-recombinase under the Glp1r promoter were crossed with either a ROSA26 eYFP or tdRFP reporter strain to identify GLP-1R expressing cells. Patch-clamp recordings were performed on tdRFP-positive neurons in acute coronal brain slices from adult mice and selective targeting of GLP-1R cells in vivo was achieved using viral gene delivery.
RESULTS: Large numbers of eYFP or tdRFP immunoreactive cells were found in the circumventricular organs, amygdala, hypothalamic nuclei and the ventrolateral medulla. Smaller numbers were observed in the nucleus of the solitary tract and the thalamic paraventricular nucleus. However, tdRFP positive neurons were also found in areas without preproglucagon-neuronal projections like hippocampus and cortex. GLP-1R cells were not immunoreactive for GFAP or parvalbumin although some were catecholaminergic. GLP-1R expression was confirmed in whole-cell recordings from BNST, hippocampus and PVN, where 100 nM GLP-1 elicited a reversible inward current or depolarisation. Additionally, a unilateral stereotaxic injection of a cre-dependent AAV into the PVN demonstrated that tdRFP-positive cells express cre-recombinase facilitating virally-mediated eYFP expression.
CONCLUSIONS: This study is a comprehensive description and phenotypic analysis of GLP-1R expression in the mouse CNS. We demonstrate the power of combining the GLP-1R-CRE mouse with a virus to generate a selective molecular handle enabling future in vivo investigation as to their physiological importance.
方法:将在Glp1r启动子下表达Cre重组酶的小鼠与ROSA26eYFP或tdRFP报告株杂交,以鉴定表达GLP-1R的细胞。对成年小鼠急性冠状脑切片中的tdRFP阳性神经元进行膜片钳记录,并使用病毒基因递送实现体内GLP-1R细胞的选择性靶向。
结果:在室外器官中发现了大量的eYFP或tdRFP免疫反应细胞,杏仁核,下丘脑核和腹外侧延髓。在孤束核和丘脑室旁核中观察到较小的数量。然而,在没有前胰高血糖素原-神经元突起的区域如海马和皮质中也发现了tdRFP阳性神经元。GLP-1R细胞对GFAP或小白蛋白没有免疫反应性,尽管有些是儿茶酚胺能的。GLP-1R表达在来自BNST的全细胞记录中得到证实,海马和PVN,其中100nMGLP-1引发可逆的内向电流或去极化。此外,向PVN中单侧立体定向注射cre依赖性AAV证明tdRFP阳性细胞表达cre重组酶促进病毒介导的eYFP表达。
结论:本研究是对小鼠CNS中GLP-1R表达的全面描述和表型分析。我们证明了将GLP-1R-CRE小鼠与病毒结合以产生选择性分子柄的能力,从而能够对其生理重要性进行未来的体内研究。