Cell-induced collagen alignment in a 3D in vitro culture during extracellular matrix production
Researchers have unveiled new insights into the organization of the bone extracellular matrix by studying a 3D cell culture system. Their work, employing live fluorescence imaging and volume electron microscopy, sheds light on how osteogenic cells deposit and orient the collagen matrix, which is subsequently mineralized. The study reveals that during development, osteoblasts actively organize the collagen matrix, forming tunnel-like structures surrounded by aligned collagen. This suggests that as osteoblasts migrate through the culture, they play a crucial role in organizing the collagen. Notably, this process of collagen alignment occurs independently of osteoclast activity. The findings highlight the importance of cell-matrix interactions in the early stages of osteogenic differentiation and enhance our understanding of matrix organization in bone development.
According to Judith Schaart "Dragonfly was very useful to visualize and analyze the 3-dimensional cell-matrix environment in collagen-producing cell cultures by automated segmentation of the cells and collagen in our FIB/SEM stacks."
Video presentation
Publication
Schaart, J. M., Kea-te Lindert, M., Roverts, R., Nijhuis, W. H., Sommerdijk, N., & Akiva, A. (2024). Cell-induced collagen alignment in a 3D in vitro culture during extracellular matrix production. Journal of Structural Biology, 216, 107332. https://doi.org/10.1016/j.jsb.2024.108096
Research Center
Department of Medical BioSciences, Radboud University Medical Center, Geert Grooteplein Zuid 28, 6525GA Nijmegen, The Netherlands
Electron Microscopy Center, Radboudumc Technology Center Microscopy, Radboud University Medical Center, Geert Grooteplein Noord 29, 6525EZ Nijmegen, The Netherlands
Department of Orthopaedic Surgery, University Medical Centre Utrecht, Wilhelmina Children’s Hospital, 3508GA Utrecht, The Netherlands
Keywords: Osteogenic differentiation, Collagen alignment, 3D cell culture, 3D FIB/SEM, Volume electron microscopy
A) FIB/SEM images showed collagen aligning around a cell-free space from a cell protrusion. B) 3D reconstruction revealed this space as a tunnel, with collagen density decreasing further from the tunnel's center.
A) FIB/SEM imaging revealed cell-free voids encircled by dense, aligned collagen, with a gradient observed further from the cell. B) 3D reconstruction shows segmented collagen (magenta) around a cell-shaped void.
3D reconstruction of segmented cells from 3D AT-SEM in the fibrin-rich core of the culture reveals multiple protrusions and intercellular connections.
Representative slide of color-based volume thickness analysis of segmented collagen, showing a cell protrusion linked to a tunnel within denser, aligned collagen.