School of Life Science and Technology, Shanghai Tech University, Shanghai, People's Republic of China.
State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell, Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, People's Republic of China.
Stem Cells. 2022 Sep 26;40(9):857-869. doi: 10.1093/stmcls/sxac046.
G-protein-coupled receptors (GPCRs) reportedly relay specific signals, such as dopamine and serotonin, to regulate neurogenic processes although the underlying signaling pathways are not fully elucidated. Based on our previous work, which demonstrated dopamine receptor D1 (DRD1) effectively induces the proliferation of human neural stem cells, here we continued to show the knockout of β-arrestin 2 by CRISPR/Cas9 technology significantly weakened the DRD1-induced proliferation and neurosphere growth. Furthermore, inhibition of the downstream p38 MAPK by its specific inhibitors or small hairpin RNA mimicked the weakening effect of β-arrestin 2 knockout. In addition, blocking of Epac2, a PKA independent signal pathway, by its specific inhibitors or small hairpin RNA also significantly reduced DRD1-induced effects. Simultaneous inhibition of β-arrestin 2/p38 MAPK and Epac2 pathways nearly abolished the DRD1-stimulated neurogenesis, indicating the cooperative contribution of both pathways. Consistently, the expansion and folding of human cerebral organoids as stimulated by DRD1 were also mediated cooperatively by both β-arrestin 2/p38 MAPK and Epac2 pathways. Taken together, our results reveal that GPCRs apply at least 2 different signal pathways to regulate neurogenic processes in a delicate and balanced manners.
G 蛋白偶联受体（GPCRs）据报道能传递特定的信号，如多巴胺和血清素，以调节神经发生过程，尽管其潜在的信号通路尚未完全阐明。基于我们之前的工作，该工作表明多巴胺受体 D1（DRD1）能有效诱导人神经干细胞的增殖，在这里我们继续展示通过 CRISPR/Cas9 技术敲除β-arrestin 2 显著削弱了 DRD1 诱导的增殖和神经球生长。此外，通过其特异性抑制剂或短发夹 RNA 抑制下游 p38 MAPK 模拟了β-arrestin 2 敲除的削弱作用。此外，通过其特异性抑制剂或短发夹 RNA 阻断 Epac2（一种不依赖 PKA 的信号通路）也显著降低了 DRD1 诱导的作用。同时抑制β-arrestin 2/p38 MAPK 和 Epac2 通路几乎完全消除了 DRD1 刺激的神经发生，表明这两条通路的协同作用。一致地，DRD1 刺激的人大脑类器官的扩增和折叠也被β-arrestin 2/p38 MAPK 和 Epac2 通路协同介导。总之，我们的结果揭示了 GPCRs 至少应用 2 种不同的信号通路以精细和平衡的方式调节神经发生过程。
