Institute of Life Sciences, Fuzhou University, Fuzhou, Fujian, 350116, China.
Department of Mathematics, Fuzhou University, Fuzhou, Fujian, 350116, China.
Nat Commun. 2018 Apr 9;9(1):1345. doi: 10.1038/s41467-018-03801-z.
Branching morphogenesis is a general mechanism that increases the surface area of an organ. In chicken feathers, the flat epithelial sheath at the base of the follicle is transformed into periodic branches. How exactly the keratinocytes are organized into this pattern remains unclear. Here we show that in the feather follicle, the pre-branch basal keratinocytes have extensive filopodia, which contract and smooth out after branching. Manipulating the filopodia via small GTPases RhoA/Cdc42 also regulates branch formation. These basal filopodia help interpret the proximal-distal FGF gradient in the follicle. Furthermore, the topological arrangement of cell adhesion via E-Cadherin re-distribution controls the branching process. Periodic activation of Notch signaling drives the differential cell adhesion and contraction of basal filopodia, which occurs only below an FGF signaling threshold. Our results suggest a coordinated adjustment of cell shape and adhesion orchestrates feather branching, which is regulated by Notch and FGF signaling.
分支形态发生是一种增加器官表面积的通用机制。在鸡的羽毛中,毛囊基部的扁平上皮鞘会转变成周期性的分支。角蛋白细胞究竟是如何组织成这种模式的,目前还不清楚。在这里,我们发现,在羽毛毛囊中,分支前的基底角蛋白细胞有广泛的丝状伪足,在分支后收缩并变平。通过小 GTP 酶 RhoA/Cdc42 操纵丝状伪足也调节了分支的形成。这些基底丝状伪足有助于解释毛囊中的近端-远端 FGF 梯度。此外,通过 E-钙粘蛋白重新分布的细胞黏附的拓扑排列控制分支过程。周期性激活 Notch 信号驱动基底丝状伪足的差异细胞黏附和收缩,这种收缩仅发生在 FGF 信号阈值以下。我们的结果表明,细胞形状和黏附的协调调整支配着羽毛的分支,这是由 Notch 和 FGF 信号调节的。