Phenotypic Changes, Signaling Pathway, and Functional Correlates of GPR17-expressing Neural Precursor Cells during Oligodendrocyte Differentiation
Phenotypic Changes, Signaling Pathway, and Functional Correlates of GPR17-expressing Neural Precursor Cells during Oligodendrocyte Differentiation
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DOI：
10.1074/jbc.m110.162867
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发表时间：
2011-03-25
影响因子：
4.8
通讯作者：
Abbracchio, Maria P.
中科院分区：
文献类型：
--
作者：
Fumagalli, Marta;Daniele, Simona;Abbracchio, Maria P.
发育和成熟的中枢神经系统含有表达蛋白聚糖NG2的神经前体细胞。其中一些细胞不断分化为形成髓磷脂的少突胶质细胞；对NG2（+）前体命运的了解将受益于对新的关键功能参与者的描述。在这方面，G蛋白偶联膜受体GPR17最近作为少突胶质细胞发生的新计时器出现。在这里，我们使用纯化的少突胶质前体细胞（OPCs）来全面定义表达GPR17的细胞在OPC分化过程中的免疫表型，揭示其天然信号通路，并评估GPR17被其推测的内源性配体，尿嘧啶核苷酸和半胱氨酸白三烯（cysLTs）激活的功能后果。GPR17的存在仅限于极早期分化阶段，与成熟髓磷脂完全分离。具体来说，GPR17修饰了两个缓慢增殖的NG2(+) OPCs亚群：(i)形态学上未成熟的细胞，表达其他早期蛋白，如Olig2和PDGF受体- α； （ii）分化的前少突胶质细胞，表达更成熟的因子，如O4和O1。因此，GPR17是这些过渡阶段的新标记物。在OPCs中，尿嘧啶核苷酸或cylts激活GPR17可有效抑制细胞内cAMP的形成。这种作用被GPR17拮抗剂和sirna受体沉默所抵消。最后，尿嘧啶核苷酸通过拮抗剂或sirna促进和抑制GPR17，破坏了正常的OPC分化程序。这些数据暗示了NG2(+) OPCs的体内行为，并指出尿嘧啶核苷酸和cylts是生理条件下和髓鞘修复过程中这些细胞的主要外源性局部调节因子。
The developing and mature central nervous system contains neural precursor cells expressing the proteoglycan NG2. Some of these cells continuously differentiate to myelin-forming oligodendrocytes; knowledge of the destiny of NG2(+) precursors would benefit from the characterization of new key functional players. In this respect, the G protein-coupled membrane receptor GPR17 has recently emerged as a new timer of oligodendrogliogenesis. Here, we used purified oligodendrocyte precursor cells (OPCs) to fully define the immunophenotype of the GPR17-expressing cells during OPC differentiation, unveil its native signaling pathway, and assess the functional consequences of GPR17 activation by its putative endogenous ligands, uracil nucleotides and cysteinyl leukotrienes (cysLTs). GPR17 presence was restricted to very early differentiation stages and completely segregated from that of mature myelin. Specifically, GPR17 decorated two subsets of slowly proliferating NG2(+) OPCs: (i) morphologically immature cells expressing other early proteins like Olig2 and PDGF receptor-alpha, and (ii) ramified preoligodendrocytes already expressing more mature factors, like O4 and O1. Thus, GPR17 is a new marker of these transition stages. In OPCs, GPR17 activation by either uracil nucleotides or cysLTs resulted in potent inhibition of intracellular cAMP formation. This effect was counteracted by GPR17 antagonists and receptor silencing with siRNAs. Finally, uracil nucleotides promoted and GPR17 inhibition, by either antagonists or siRNAs, impaired the normal program of OPC differentiation. These data have implications for the in vivo behavior of NG2(+) OPCs and point to uracil nucleotides and cysLTs as main extrinsic local regulators of these cells under physiological conditions and during myelin repair.