Moore Emma, Zhao Ruonan, McKinney Mary C, Yi Kexi, Wood Christopher, Trainor Paul
Stowers Institute for Medical Research, Kansas City, MO, USA.
Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA.
bioRxiv. 2024 Mar 12:2024.03.09.584232. doi: 10.1101/2024.03.09.584232.
Neural crest cells (NCC) comprise a heterogeneous population of cells with variable potency, that contribute to nearly every tissue and organ system throughout the body. Considered unique to vertebrates, NCC are transiently generated within the dorsolateral region of the neural plate or neural tube, during neurulation. Their delamination and migration are crucial events in embryo development as the differentiation of NCC is heavily influenced by their final resting locations. Previous work in avian and aquatic species has shown that NCC delaminate via an epithelial-mesenchymal transition (EMT), which transforms these stem and progenitor cells from static polarized epithelial cells into migratory mesenchymal cells with fluid front and back polarity. However, the cellular and molecular drivers facilitating NCC delamination in mammals are poorly understood. We performed live timelapse imaging of NCC delamination in mouse embryos and discovered a group of cells that exit the neuroepithelium as isolated round cells, which then halt for a short period prior to acquiring the mesenchymal migratory morphology classically associated with most delaminating NCC. High magnification imaging and protein localization analyses of the cytoskeleton, together with measurements of pressure and tension of delaminating NCC and neighboring neuroepithelial cells, revealed these round NCC are extruded from the neuroepithelium prior to completion of EMT. Furthermore, we demonstrate that cranial NCC are extruded through activation of the mechanosensitive ion channel, PIEZO1, a key regulator of the live cell extrusion pathway, revealing a new role for PIEZO1 in neural crest cell development. Our results elucidating the cellular and molecular dynamics orchestrating NCC delamination support a model in which high pressure and tension in the neuroepithelium results in activation of the live cell extrusion pathway and delamination of a subpopulation of NCC in parallel with EMT. This model has broad implications for our understanding of cell delamination in development and disease.
神经嵴细胞（NCC）是一群具有不同分化潜能的异质性细胞，它们对全身几乎每个组织和器官系统都有贡献。NCC被认为是脊椎动物所特有的，在神经胚形成过程中，它们在神经板或神经管的背外侧区域短暂生成。它们的脱层和迁移是胚胎发育中的关键事件，因为NCC的分化在很大程度上受到其最终静止位置的影响。先前在鸟类和水生动物中的研究表明，NCC通过上皮-间质转化（EMT）进行脱层，这种转化将这些干细胞和祖细胞从静态极化的上皮细胞转变为具有流体前后极性的迁移性间充质细胞。然而，促进哺乳动物NCC脱层的细胞和分子驱动因素却知之甚少。我们对小鼠胚胎中的NCC脱层进行了实时延时成像，发现了一组以孤立的圆形细胞形式离开神经上皮的细胞，这些细胞在获得与大多数脱层NCC经典相关的间充质迁移形态之前会短暂停顿。对细胞骨架的高倍成像和蛋白质定位分析，以及对脱层NCC和邻近神经上皮细胞的压力和张力测量，揭示这些圆形NCC在EMT完成之前就从神经上皮中挤出。此外，我们证明颅神经嵴细胞通过机械敏感离子通道PIEZO1的激活而被挤出，PIEZO1是活细胞挤出途径的关键调节因子，揭示了PIEZO1在神经嵴细胞发育中的新作用。我们阐明NCC脱层的细胞和分子动力学的结果支持了一个模型，即神经上皮中的高压和张力导致活细胞挤出途径的激活以及与EMT并行的一部分NCC的脱层。该模型对我们理解发育和疾病中的细胞脱层具有广泛的意义。
