Stretch-dependent changes in molecular conformation in fibronectin nanofibers

Szymanski, John M.; Sevcik, Emily N.; Zhang, Kairui; Feinberg, Adam W.

doi:10.1039/c7bm00370f

Cited by 16 publications

(19 citation statements)

References 39 publications

(82 reference statements)

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“…The Fn cryptic binding sites can be exposed by tension, heat denaturation, or cleavage of specific domains (e.g., FnIII) [58,59]. Fn is therefore mechanosensitive and the application of force can induce conformational changes in the Fn molecule [60]. For instance, the Fn type III repeat contains hydrogen bonds which are thought to be susceptible to unfolding by pressure or mechanical tension.…”

Section: Discussionmentioning

confidence: 99%

Coupling of Fibrin Reorganization and Fibronectin Patterning by Corneal Fibroblasts in Response to PDGF BB and TGFβ1

Miron-Mendoza¹,

Vazquez²,

García-Rámila³

et al. 2020

Bioengineering

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We previously reported that corneal fibroblasts within 3D fibrin matrices secrete, bind, and organize fibronectin into tracks that facilitate cell spreading and migration. Other cells use these fibronectin tracks as conduits, which leads to the development of an interconnected cell/fibronectin network. In this study, we investigate how cell-induced reorganization of fibrin correlates with fibronectin track formation in response to two growth factors present during wound healing: PDGF BB, which stimulates cell spreading and migration; and TGFβ1, which stimulates cellular contraction and myofibroblast transformation. Both PDGF BB and TGFβ1 stimulated global fibrin matrix contraction (p < 0.005); however, the cell and matrix patterning were different. We found that, during PDGF BB-induced cell spreading, fibronectin was organized simultaneously with the generation of tractional forces at the leading edge of pseudopodia. Over time this led to the formation of an interconnected network consisting of cells, fibronectin and compacted fibrin tracks. Following culture in TGFβ1, cells were less motile, produced significant local fibrin reorganization, and formed fewer cellular connections as compared to PDGF BB (p < 0.005). Although bands of compacted fibrin tracks developed in between neighboring cells, fibronectin labeling was not generally present along these tracks, and the correlation between fibrin and fibronectin labeling was significantly less than that observed in PDGF BB (p < 0.001). Taken together, our results show that cell-induced extracellular matrix (ECM) reorganization can occur independently from fibronectin patterning. Nonetheless, both events seem to be coordinated, as corneal fibroblasts in PDGF BB secrete and organize fibronectin as they preferentially spread along compacted fibrin tracks between cells, producing an interconnected network in which cells, fibronectin and compacted fibrin tracks are highly correlated. This mechanism of patterning could contribute to the formation of organized cellular networks that have been observed following corneal injury and refractive surgery.

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Section: Discussionmentioning

confidence: 99%

Coupling of Fibrin Reorganization and Fibronectin Patterning by Corneal Fibroblasts in Response to PDGF BB and TGFβ1

Miron-Mendoza¹,

Vazquez²,

García-Rámila³

et al. 2020

Bioengineering

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“…To do this we engineered FN nanofibers that were ~67 μm wide and 1 cm long. The FN nanofibers were first tagged with FN-based fiducial marks through a modification of a previously published Patterning-on-Topography method (Supplementary Figure 1 ) 30 , 31 . These fiducial marks consisted of a second layer of FN patterned at defined intervals longitudinally along the FN nanofibers, and could be clearly observed in phase-contrast, fluorescent and atomic force microscopies.…”

Section: Resultsmentioning

confidence: 99%

“…To strain FN nanofibers we used our previously published technique 31 . We first microcontact printed 1 cm long and 67 μm wide lines of FN that have been tagged with fiducial marks (Supplementary Figure 1 ).…”

Section: Methodsmentioning

confidence: 99%

Measuring the Poisson’s Ratio of Fibronectin Using Engineered Nanofibers

Szymanski

Zhang

Feinberg

2017

Sci Rep

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The extracellular matrix (ECM) is a fibrillar protein-based network, the physical and chemical properties of which can influence a multitude of cellular processes. Despite having an important role in cell and tissue signaling, a complete chemo-mechanical characterization of ECM proteins such as fibronectin (FN) is lacking. In this study, we engineered monodisperse FN nanofibers using a surface-initiated assembly technique in order to provide new insight into the elastic behavior of this material over large deformations. FN nanofibers were patterned on surfaces in a pre-stressed state and when released from the surface underwent rapid contraction. We found that the FN nanofibers underwent 3.3-fold and 9-fold changes in length and width, respectively, and that the nanofiber volume was conserved. Volume was also conserved following uniaxial extension of the FN nanofibers of ~2-fold relative to the patterned state. This data suggests that the FN networks we engineered formed an incompressible material with a Poisson’s ratio of ~0.5. While the Poisson’s ratio of cells and other biological materials are widely estimated as 0.5, our experimental results demonstrate that for FN networks this is a reasonable approximation.

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“…Does the structure of the fibronectin molecule matter? Single fibronectin strands are 2 nm wide, with domains that uncoil under stress to reveal cryptic binding domains [30][31][32]. There is significant evidence that the nanoscale structure of fibronectin in particular plays a key role in regulating diverse cell behaviors [33][34][35] and the same effect is likely to be observed in many other ECM components.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, we used whole-mount confocal microscopy to characterize the structure and composition of ECM components in the developing heart with a focus on fibronectin. The chick embryo served as a model system because, at early time points, it is similar to the human embryo and provides easy access to the heart throughout development (stages Hamburger-Hamilton (HH) [27][28][29][30][31][32][33][34][35] [13]. This range was selected because it is the earliest stage at which highly-aligned layers of myocardium have formed in the ventricular wall, and the vasculature including capillaries begin to develop.…”

Section: Introductionmentioning

confidence: 99%

Extracellular Matrix Structure and Composition in the Early Four-Chambered Embryonic Heart

Jallerat

Feinberg

2020

Cells

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During embryonic development, the heart undergoes complex morphogenesis from a liner tube into the four chambers consisting of ventricles, atria and valves. At the same time, the cardiomyocytes compact into a dense, aligned, and highly vascularized myocardium. The extracellular matrix (ECM) is known to play an important role in this process but understanding of the expression and organization remains incomplete. Here, we performed 3D confocal imaging of ECM in the left ventricle and whole heart of embryonic chick from stages Hamburger-Hamilton 28–35 (days 5–9) as an accessible model of heart formation. First, we observed the formation of a fibronectin-rich, capillary-like networks in the myocardium between day 5 and day 9 of development. Then, we focused on day 5 prior to vascularization to determine the relative expression of fibronectin, laminin, and collagen type IV. Cardiomyocytes were found to uniaxially align prior to vascularization and, while the epicardium contained all ECM components, laminin was reduced, and collagen type IV was largely absent. Quantification of fibronectin revealed highly aligned fibers with a mean diameter of ~500 nm and interfiber spacing of ~3 µm. These structural parameters (volume, spacing, fiber diameter, length, and orientation) provide a quantitative framework to describe the organization of the embryonic ECM.

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Stretch-dependent changes in molecular conformation in fibronectin nanofibers

Cited by 16 publications

References 39 publications

Coupling of Fibrin Reorganization and Fibronectin Patterning by Corneal Fibroblasts in Response to PDGF BB and TGFβ1

Coupling of Fibrin Reorganization and Fibronectin Patterning by Corneal Fibroblasts in Response to PDGF BB and TGFβ1

Measuring the Poisson’s Ratio of Fibronectin Using Engineered Nanofibers

Extracellular Matrix Structure and Composition in the Early Four-Chambered Embryonic Heart

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