A Role for Intermediate Radial Glia in the Tangential Expansion of the Mammalian Cerebral Cortex
A Role for Intermediate Radial Glia in the Tangential Expansion of the Mammalian Cerebral Cortex
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DOI：
10.1093/cercor/bhq238
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发表时间：
2011-07-01
期刊：
影响因子：
3.7
通讯作者：
Borrell, Victor
中科院分区：
文献类型：
--
作者：
Reillo, Isabel;de Juan Romero, Camino;Borrell, Victor
大型哺乳动物的大脑皮层在发育过程中经历了巨大的表面积扩张和折叠。很可能存在特定的机制来协调皮质在表面积而不是厚度上的生长，但它们尚未被确定。通过分析多个物种，我们已经确定了一种专门的祖细胞类型，这种祖细胞是具有折叠大脑皮层的哺乳动物所独有的，我们将其命名为中间放射状胶质细胞（IRGC）。IRGC表达Pax6但不表达Tbr 2，具有接触软膜表面但不接触心室表面的放射状纤维，并且在脑室下内区和脑室下外区（OSVZ）中均发现IRGC。我们发现，IRGC大量产生的OSVZ，从而增加了径向纤维的数量。这种扩张的放射状纤维支架的扇出促进了放射状迁移神经元的切向分散，从而允许皮质片的表面区域中的生长。因此，特定皮质区域的切向扩张之前，在底层OSVZ的高增殖，而IRGC的实验减少损害了神经元的切向分散，并导致在一个较小的皮质表面。因此，IRGC的产生在哺乳动物大脑皮层的切向扩张中起着关键作用。
The cerebral cortex of large mammals undergoes massive surface area expansion and folding during development. Specific mechanisms to orchestrate the growth of the cortex in surface area rather than in thickness are likely to exist, but they have not been identified. Analyzing multiple species, we have identified a specialized type of progenitor cell that is exclusive to mammals with a folded cerebral cortex, which we named intermediate radial glia cell (IRGC). IRGCs express Pax6 but not Tbr2, have a radial fiber contacting the pial surface but not the ventricular surface, and are found in both the inner subventricular zone and outer subventricular zone (OSVZ). We find that IRGCs are massively generated in the OSVZ, thus augmenting the numbers of radial fibers. Fanning out of this expanding radial fiber scaffold promotes the tangential dispersion of radially migrating neurons, allowing for the growth in surface area of the cortical sheet. Accordingly, the tangential expansion of particular cortical regions was preceded by high proliferation in the underlying OSVZ, whereas the experimental reduction of IRGCs impaired the tangential dispersion of neurons and resulted in a smaller cortical surface. Thus, the generation of IRGCs plays a key role in the tangential expansion of the mammalian cerebral cortex.