Cuevas Estela, Ausó Eva, Telefont Martin, Morreale de Escobar Gabriella, Sotelo Constantino, Berbel Pere
Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 Sant Joan d'Alacant, Alicante, Spain.
Eur J Neurosci. 2005 Aug;22(3):541-51. doi: 10.1111/j.1460-9568.2005.04243.x.
Correct positioning of cortical neurons during development depends on the radial migration of the projection neurons and on the coordinated tangential and radial migrations of the subcortically generated interneurons. As previously shown, a transient and moderate maternal deficiency in thyroxin during early corticogenesis alters the radial migration of projection neurons. To determine if a similar effect might also affect tangential migration of medial ganglionic eminence (MGE)-derived neurons at the origin of cortical interneurons, explants of MGE from green fluorescent protein (GFP)-transgenic embryos were implanted into flat cortical mounts from wild-type embryos. The distances covered and the preferential migration (medially) of GFP-MGE neurons from embryos of hypothyroxinemic dams are not affected in their tangential migration into wild-type control cortices. In contrast, when GFP-MGE neurons from embryos of control or hypothyroxinemic dams migrate within cortices from embryos of hypothyroxinemic dams, the GFP-MGE-derived neurons lose their preferential direction of migration, although they still migrate for long distances throughout the cortex. Our results show that maternal hypothyroxinemia alters the tangential migration of GFP-MGE-derived neurons in the neocortex of the progeny and suggest that this alteration is not derived from the migratory neurons themselves but through undefined short- and long-range cues responsible for the guidance of their migration.
发育过程中皮质神经元的正确定位取决于投射神经元的径向迁移以及皮质下产生的中间神经元的切向和径向协同迁移。如先前所示，在早期皮质发生过程中，母体甲状腺素短暂且适度缺乏会改变投射神经元的径向迁移。为了确定类似的影响是否也会影响皮质中间神经元起源的内侧神经节隆起（MGE）衍生神经元的切向迁移，将来自绿色荧光蛋白（GFP）转基因胚胎的MGE外植体植入野生型胚胎的扁平皮质标本中。来自甲状腺功能减退母鼠胚胎的GFP-MGE神经元在向野生型对照皮质的切向迁移中，其迁移距离和优先迁移方向（向内侧）不受影响。相反，当来自对照或甲状腺功能减退母鼠胚胎的GFP-MGE神经元在来自甲状腺功能减退母鼠胚胎的皮质内迁移时，GFP-MGE衍生的神经元失去了它们优先的迁移方向，尽管它们仍然在整个皮质中进行长距离迁移。我们的结果表明，母体甲状腺功能减退会改变后代新皮质中GFP-MGE衍生神经元的切向迁移，并表明这种改变不是源自迁移神经元本身，而是通过负责引导其迁移的未定义的短程和长程线索。
