Laboratoire Physico-chimie Curie, Paris, France.
Biophys J. 2011 Jun 8;100(11):2566-75. doi: 10.1016/j.bpj.2011.04.047.
Collective cell migration is often characterized by the spontaneous onset of multicellular protrusions (known as fingers) led by a single leader cell. Working with epithelial Madin-Darby canine kidney monolayers we show that cells within the fingers, as compared with the epithelium, are well oriented and polarized along the main finger direction, which suggests that these cells actively migrate. The cell orientation and polarity decrease continuously from the tip toward the epithelium over a penetration distance of typically two finger lengths. Furthermore, laser photoablation experiments at various locations along these fingers demonstrate that the cells in the fingers are submitted to a tensile stress whose value is larger close to the tip. From a dynamical point of view, cells entering a finger gradually polarize on timescales that depend upon their particular initial position. Selective laser nanosurgery of the leader lamellipodium shows not only that these structures need a leader to progress, but that this leader itself is the consequence of a prior self-organization of the cells forming the finger. These results highlight the complex interplay between the collective orientation within the fingers and the mechanical action of the leader.
细胞集体迁移的特征通常是由单个先导细胞自发引发的多细胞突起（称为指状突起）。我们在研究上皮细胞 Madin-Darby 犬肾单层细胞时发现，与上皮细胞相比，指状突起内的细胞沿主要指状突起方向定向和极化良好，这表明这些细胞在主动迁移。细胞定向和极性从尖端到上皮细胞逐渐连续下降，穿透距离通常为两个指状突起的长度。此外，在这些指状突起的不同位置进行激光光烧蚀实验表明，指状突起内的细胞受到张力的作用，在靠近尖端的位置，其值较大。从动力学的角度来看，进入指状突起的细胞逐渐在依赖于其特定初始位置的时间尺度上极化。对先导片状伪足的选择性激光纳米手术不仅表明这些结构需要一个先导才能前进，而且这个先导本身是形成指状突起的细胞先前自组织的结果。这些结果强调了指状突起内的集体定向和先导的机械作用之间的复杂相互作用。
