Lansky Zipora, Mutsafi Yael, Houben Lothar, Ilani Tal, Armony Gad, Wolf Sharon G, Fass Deborah
Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel.
J Struct Biol X. 2019 Jan-Mar;1:100002. doi: 10.1016/j.yjsbx.2018.100002.
Cells and extracellular matrix (ECM) are mutually interdependent: cells guide self-assembly of ECM precursors, and the resulting ECM architecture supports and instructs cells. Though bidirectional signaling between ECM and cells is fundamental to cell biology, it is challenging to gain high-resolution structural information on cellular responses to the matrix microenvironment. Here we used cryo-scanning transmission electron tomography (CSTET) to reveal the nanometer- to micron-scale organization of major fibroblast ECM components in a native-like context, while simultaneously visualizing internal cell ultrastructure including organelles and cytoskeleton. In addition to extending current models for collagen VI fibril organization, three-dimensional views of thick cell regions and surrounding matrix showed how ECM networks impact the structures and dynamics of intracellular organelles and how cells remodel ECM. Collagen VI and fibronectin were seen to distribute in fundamentally different ways in the cell microenvironment and perform distinct roles in supporting and interacting with cells. This work demonstrates that CSTET provides a new perspective for the study of ECM in cell biology, highlighting labeled extracellular elements against a backdrop of unlabeled but morphologically identifiable cellular features with nanometer resolution detail.
细胞与细胞外基质（ECM）相互依存：细胞引导ECM前体的自组装，而形成的ECM结构则支持并指导细胞。尽管ECM与细胞之间的双向信号传导是细胞生物学的基础，但要获得关于细胞对基质微环境反应的高分辨率结构信息却具有挑战性。在这里，我们使用冷冻扫描透射电子断层扫描（CSTET）来揭示天然环境中主要成纤维细胞ECM成分的纳米到微米尺度的组织，同时可视化包括细胞器和细胞骨架在内的细胞内部超微结构。除了扩展当前关于VI型胶原纤维组织的模型外，厚细胞区域和周围基质的三维视图还展示了ECM网络如何影响细胞内细胞器的结构和动态，以及细胞如何重塑ECM。研究发现，VI型胶原和纤连蛋白在细胞微环境中的分布方式截然不同，在支持细胞和与细胞相互作用方面发挥着不同的作用。这项工作表明，CSTET为细胞生物学中ECM的研究提供了一个新的视角，以纳米分辨率的细节突出了在未标记但形态可识别的细胞特征背景下的标记细胞外成分。
