INSERM, UMR-S839, Institut du Fer à Moulin, Paris, France; Sorbonne Université, Institut du Fer à Moulin, UMR-S839, Paris, France; Physico-Chimie Curie, UMR-168, Université PSL, Sorbonne Paris Cité, CNRS, Paris, France.
INSERM, UMR-S839, Institut du Fer à Moulin, Paris, France; Sorbonne Université, Institut du Fer à Moulin, UMR-S839, Paris, France.
Biomaterials. 2019 Sep;214:119194. doi: 10.1016/j.biomaterials.2019.05.005. Epub 2019 May 14.
In mammalian embryos, cortical interneurons travel long distances among complex three-dimensional tissues before integrating into cortical circuits. Several molecular guiding cues involved in this migration process have been identified, but the influence of physical parameters remains poorly understood. In the present study, we have investigated in vitro the influence of the topography of the microenvironment on the migration of primary cortical interneurons released from mouse embryonic explants. We found that arrays of PDMS micro-pillars of 10 μm size and spacing, either round or square, influenced both the morphology and the migratory behavior of interneurons. Strikingly, most interneurons exhibited a single and long leading process oriented along the diagonals of the square pillared array, whereas leading processes of interneurons migrating in-between round pillars were shorter, often branched and oriented in all available directions. Accordingly, dynamic studies revealed that growth cone divisions were twice more frequent in round than in square pillars. Both soma and leading process tips presented forward directed movements within square pillars, contrasting with the erratic trajectories and more dynamic movements observed among round pillars. In support of these observations, long interneurons migrating in square pillars displayed tight bundles of stable microtubules aligned in the direction of migration. Overall, our results show that micron-sized topography provides global spatial constraints promoting the establishment of different morphological and migratory states. Remarkably, these different states belong to the natural range of migratory behaviors of cortical interneurons, highlighting the potential importance of topographical cues in the guidance of these embryonic neurons, and more generally in brain development.
在哺乳动物胚胎中，皮质中间神经元在整合到皮质回路之前，需要在复杂的三维组织中进行长距离迁移。已经确定了几种参与这种迁移过程的分子导向线索，但对物理参数的影响仍知之甚少。在本研究中，我们研究了体外微环境的拓扑结构对从小鼠胚胎外植体中释放的原代皮质中间神经元迁移的影响。我们发现，10 µm 大小和间距的 PDMS 微柱阵列，无论是圆形还是方形，都会影响中间神经元的形态和迁移行为。引人注目的是，大多数中间神经元表现出单一的、长的主导突起，沿方形柱状阵列的对角线定向，而在圆形柱状物之间迁移的中间神经元的主导突起较短，通常分支并沿所有可用方向定向。相应地，动态研究表明，圆形支柱中生长锥分裂的频率是方形支柱中的两倍。胞体和主导突起尖端都在方形支柱内向前运动，与在圆形支柱中观察到的不稳定轨迹和更动态的运动形成对比。支持这些观察结果，在方形支柱中迁移的长中间神经元显示出紧密的稳定微管束，排列在迁移方向上。总的来说，我们的结果表明，微米级的拓扑结构提供了全局的空间限制，促进了不同形态和迁移状态的建立。值得注意的是，这些不同的状态属于皮质中间神经元自然迁移行为的范围，突出了地形线索在这些胚胎神经元导向中的潜在重要性，更普遍地说，在大脑发育中也是如此。
