Dissecting the Factors Involved in the Locomotion Mode of Neuronal Migration in the Developing Cerebral Cortex
Dissecting the Factors Involved in the Locomotion Mode of Neuronal Migration in the Developing Cerebral Cortex
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DOI：
10.1074/jbc.m109.033761
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发表时间：
2010-02-19
影响因子：
4.8
通讯作者：
Kawauchi, Takeshi
中科院分区：
文献类型：
--
作者：
Nishimura, Yoshiaki V.;Sekine, Katsutoshi;Kawauchi, Takeshi
神经元迁移对于正常的皮质层形成和大脑功能至关重要，因为迁移缺陷会导致精神发育迟滞和癫痫等神经系统疾病。神经元迁移分为几个连续的步骤：早期阶段（多极模式）、运动模式和终末易位模式。运动模式涵盖了大部分迁移路线，因此是皮质层形成的主要贡献者。然而，由于迁移早期缺陷的二次效应，分析调节这种模式的分子机制很困难。在这项研究中，我们建立了体外化学抑制剂筛选，使我们能够直接分析迁移的运动模式。 Roscovitine 和 PP2 分别是 Cdk5 和 Src 家族激酶的抑制剂，可抑制迁移的运动模式。与此一致的是，一小部分 Cdk5 或 Src 家族激酶 (Fyn) 敲低细胞表现出运动形态，但延迟了迁移，尽管大多数细胞在迁移的早期阶段停滞不前。我们还表明，广泛用作蛋白激酶 C δ (PKC δ) 特异性抑制剂的 Rottlerin 可以抑制运动模式。然而，出乎意料的是，显性失活形式以及对 PKC δ 的 RNA 干扰几乎不影响运动，但它们可能会干扰末端易位。此外，我们发现 JNK 是 Rottlerin 的潜在下游靶点。综上所述，我们的新型化学抑制剂筛选提供了 Cdk5 和 Src 家族激酶调节神经元迁移运动模式的证据。它还揭示了 Fyn 和 PKC delta 分别在迁移早期和最终阶段的作用。
Neuronal migration is essential for proper cortical layer formation and brain function, because migration defects result in neurological disorders such as mental retardation and epilepsy. Neuronal migration is divided into several contiguous steps: early phase (multipolar mode), locomotion mode, and terminal translocation mode. The locomotion mode covers most of the migration route and thereby is the main contributor to cortical layer formation. However, analysis of the molecular mechanisms regulating this mode is difficult due to the secondary effects of defects at the early phase of migration. In this study, we established an ex vivo chemical inhibitor screening, allowing us to directly analyze the locomotion mode of migration. Roscovitine and PP2, inhibitors for Cdk5 and Src family kinases, respectively, suppressed the locomotion mode of migration. In line with this, a small percentage of Cdk5- or Src family kinase (Fyn)-knockdown cells exhibited locomoting morphology but retarded migration, although the majority of cells were stalled at the early phase of migration. We also showed that rottlerin, widely used as a specific inhibitor for protein kinase C delta (PKC delta), suppressed the locomotion mode. Unexpectedly, however, the dominant-negative form as well as RNA interference for PKC delta hardly affected the locomotion, whereas they may disturb terminal translocation. In addition, we found JNK to be a potential downstream target of rottlerin. Taken together, our novel chemical inhibitor screening provides evidence that Cdk5 and Src family kinases regulate the locomotion mode of neuronal migration. It also uncovered roles for Fyn and PKC delta in the early and final phases of migration, respectively.