TY - JOUR
T1 - Fibronectin fibril alignment is established upon initiation of extracellular matrix assembly
AU - Garrison, Carly M.
AU - Schwarzbauer, Jean E.
N1 - Funding Information:
We are grateful to Wen Yih Aw and Danelle Devenport for providing the stretch chamber and to Daniel Cohen for providing PDMS stamps and sharing his micropatterning expertise. We kindly thank Berhard Wehrle-Haller and Daniel Bouvard for providing the preosteoblasts expressing RFP-tensin. We also thank Gary Laevsky, director of the Molecular Biology Confocal Microscopy Core Facility, a Nikon Center of Excellence, for his technical assistance and members of the Schwar-zbauer lab for insightful discussions. This research was funded by NIAMS R01 AR073236 (to J.E.S.), a New Jersey Commission on Cancer Research (NJCCR) DFHS18PPC041 predoctoral fellowship (to C.M.G.), and a NIH T32 GM007388 predoctoral training grant to the Department of Molecular Biology at Princeton University.
Publisher Copyright:
© 2021 Garrison and Schwarzbauer.
PY - 2021/4/15
Y1 - 2021/4/15
N2 - The physical structure of the extracellular matrix (ECM) is tissue-specific and fundamental to normal tissue function. Proper alignment of ECM fibers is essential for the functioning of a variety of tissues. While matrix assembly in general has been intensively investigated, little is known about the mechanisms required for formation of aligned ECM fibrils. We investigated the initiation of fibronectin (FN) matrix assembly using fibroblasts that assemble parallel ECM fibrils and found that matrix assembly sites, where FN fibrillogenesis is initiated, were oriented in parallel at the cell poles. We show that these polarized matrix assembly sites progress into fibrillar adhesions and ultimately into aligned FN fibrils. Cells that assemble an unaligned meshwork matrix form matrix assembly sites around the cell periphery, but the distribution of matrix assembly sites in these cells could be modulated through micropatterning or mechanical stretch. While an elongated cell shape corresponds with a polarized matrix assembly site distribution, these two features are not absolutely linked, since we discovered that transforming growth factor beta (TGF-β1) enhances matrix assembly site polarity and assembly of aligned fibrils independent of cell elongation. We conclude that the ultimate orientation of FN fibrils is determined by the alignment and distribution of matrix assembly sites that form during the initial stages of cell-FN interactions.
AB - The physical structure of the extracellular matrix (ECM) is tissue-specific and fundamental to normal tissue function. Proper alignment of ECM fibers is essential for the functioning of a variety of tissues. While matrix assembly in general has been intensively investigated, little is known about the mechanisms required for formation of aligned ECM fibrils. We investigated the initiation of fibronectin (FN) matrix assembly using fibroblasts that assemble parallel ECM fibrils and found that matrix assembly sites, where FN fibrillogenesis is initiated, were oriented in parallel at the cell poles. We show that these polarized matrix assembly sites progress into fibrillar adhesions and ultimately into aligned FN fibrils. Cells that assemble an unaligned meshwork matrix form matrix assembly sites around the cell periphery, but the distribution of matrix assembly sites in these cells could be modulated through micropatterning or mechanical stretch. While an elongated cell shape corresponds with a polarized matrix assembly site distribution, these two features are not absolutely linked, since we discovered that transforming growth factor beta (TGF-β1) enhances matrix assembly site polarity and assembly of aligned fibrils independent of cell elongation. We conclude that the ultimate orientation of FN fibrils is determined by the alignment and distribution of matrix assembly sites that form during the initial stages of cell-FN interactions.
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U2 - 10.1091/mbc.E20-08-0533
DO - 10.1091/mbc.E20-08-0533
M3 - Article
C2 - 33625865
AN - SCOPUS:85104276614
SN - 1059-1524
VL - 32
SP - 739
EP - 752
JO - Molecular biology of the cell
JF - Molecular biology of the cell
IS - 8
ER -