I.R.C.C.S. San Raffaele Pisana, Rome, Italy.
Glia. 2010 May;58(7):813-22. doi: 10.1002/glia.20965.
Neural stem cells (NSCs) isolated from the subventricular zone (SVZ) of postnatal mice, and cultured as neurospheres, expressed functional mGlu3 receptors. Following mitogen withdrawal and plating onto poly-ornitine-coated dishes, cells dissociated from the neurospheres differentiated into GFAP(+) astrocytes (about 85%), and a small percentage of beta-III tubulin(+)-neurons and O1(+)-oligodendrocytes. Activation of mGlu3 receptors with LY379268 (100 nM, applied every other day), during the differentiation period, impaired astrocyte differentiation, favoring the maintenance in culture of proliferating progenitors co-expressing GFAP with the immature markers, Sox1 and nestin. Co-treatment with the preferential mGlu2/3 receptor antagonist, LY341495 (100 nM), reversed this effect. We examined whether mGlu3 receptors could modulate the canonical signaling pathway activated by bone morphogenic proteins (BMPs), which are known to promote astrocyte differentiation of SVZ/NSCs. An acute challenge of cells isolated from the neurospheres with BMP4 (100 ng/mL) led to phosphorylation and nuclear translocation of the transcription factors, Smads. This effect was largely attenuated by the mGlu2/3 receptor agonist, LY379268. The interaction of mGlu3 and BMP4 receptors was mediated by the activation of the mitogen-activated protein kinase (MAPK) pathway. Accordingly, LY379268 failed to affect BMP receptor signaling when combined with the MAPK kinase inhibitor, UO-126 (30 muM). These data raise the intriguing possibility that glutamate regulates differentiation of SVZ/NSCs by activating mGlu3 receptors.
从新生小鼠侧脑室下区（SVZ）分离并培养为神经球的神经干细胞表达功能性 mGlu3 受体。在有丝分裂素撤出并接种到多聚鸟氨酸涂层培养皿上后，神经球解离的细胞分化为 GFAP（+）星形胶质细胞（约 85%），以及一小部分 beta-III 微管蛋白（+）神经元和 O1（+）少突胶质细胞。在分化期间，用 LY379268（100 nM，每隔一天应用一次）激活 mGlu3 受体可损害星形胶质细胞分化，有利于增殖祖细胞在培养中维持共表达 GFAP 与不成熟标志物 Sox1 和巢蛋白。与优先的 mGlu2/3 受体拮抗剂 LY341495（100 nM）共同处理可逆转这种作用。我们检查了 mGlu3 受体是否可以调节已知促进 SVZ/NSC 星形胶质细胞分化的骨形态发生蛋白（BMPs）激活的经典信号通路。用 BMP4（100 ng/mL）急性刺激神经球分离的细胞导致转录因子 Smads 的磷酸化和核易位。这种作用在很大程度上被 mGlu2/3 受体激动剂 LY379268 减弱。mGlu3 和 BMP4 受体的相互作用是通过丝裂原激活蛋白激酶（MAPK）途径的激活介导的。因此，当与 MAPK 激酶抑制剂 UO-126（30 μM）联合使用时，LY379268 未能影响 BMP 受体信号。这些数据提出了一个有趣的可能性，即谷氨酸通过激活 mGlu3 受体来调节 SVZ/NSC 的分化。
