Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
Fang Zongxi Center, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Laoshan Laboratory, Qingdao 266237, China; MoE Key Laboratory of Evolution & Marine Biodiversity, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
Curr Biol. 2023 Dec 18;33(24):5390-5403.e3. doi: 10.1016/j.cub.2023.11.001. Epub 2023 Nov 22.
Cell and tissue reshaping is crucial for coordinating three-dimensional pattern formation, in which the size and shape of the cells must be accurately regulated via signal transport and communication among tissues. However, the identity of signaling and transportation mechanisms in this process remains elusive. In our study, we identified an extracellular matrix (ECM) structure with a vertebra-like shape surrounding the central notochord tissue in the larval tail of the urochordate Ciona. Additionally, we verified that the ECM structure was formed de novo, mainly from collagens secreted by notochord cells. Fluorescence recovery after photobleaching and simulation results revealed that this structure was formed via diffusional collagen flow from a notochord that was restricted and molded in the spaces among tail tissues. We revealed that the collagen structure was essential for notochord cell arrangement and elongation. Furthermore, we observed that the central notochord connects with the epidermis through this ECM structure. The disruption of this structure by collagen knockdown and loss-of-collagen function caused the failure of notochord elongation. More importantly, the epidermis could not elongate proportionally with notochord, indicating that the collagen-rich structure serves as a scaffold to coordinate the concurrent elongation of the tail tissues. These findings provide insights into how the central tissue forms and molds its surrounding ECM structure, by not only regulating its own morphogenesis but also functioning as a scaffold for signal transmission to orchestrate the coordinated morphologic reshaping of the surrounding tissues.
细胞和组织的重塑对于协调三维形态发生至关重要，在此过程中，细胞的大小和形状必须通过组织间的信号传输和通讯进行精确调节。然而，这个过程中的信号转导和运输机制的身份仍然难以捉摸。在我们的研究中，我们在尾索动物海鞘的幼虫尾巴中发现了一种具有脊椎状形状的细胞外基质（ECM）结构，该结构围绕着中央脊索组织。此外，我们验证了该 ECM 结构是从头形成的，主要由脊索细胞分泌的胶原蛋白组成。光漂白后荧光恢复和模拟结果表明，这种结构是通过扩散性胶原蛋白从被限制和模制在尾部组织间隙中的脊索中流出而形成的。我们揭示了该胶原蛋白结构对于脊索细胞排列和伸长是必需的。此外，我们观察到中央脊索通过这个 ECM 结构与表皮相连。通过胶原蛋白敲低和胶原蛋白功能丧失破坏这种结构会导致脊索伸长失败。更重要的是，表皮不能与脊索成比例地伸长，这表明富含胶原蛋白的结构充当支架，以协调尾部组织的同时伸长。这些发现提供了关于中央组织如何形成和塑造其周围 ECM 结构的见解，不仅通过调节自身形态发生，而且还作为信号传输的支架，协调周围组织的协调形态重塑。
