![]() We further establish that the development of these streams requires intact cell-cell junctions and that stream sizes are particularly sensitive to groove depth. Here we show that unconfined endothelial cell monolayers on microgroove substrates that mimic the anisotropic organization of the extracellular matrix exhibit a specific type of collective movement that takes the form of a periodic pattern of antiparallel cell streams. Although physical confinement of cell assemblies has been shown to elicit specific patterns of collective movement in various cell types, endothelial migration in vivo often occurs without confinement. ![]() White bar = 4 m red bar = 10 nN Young's modulus = 12 kPa.Ĭollective migration of vascular endothelial cells is central for embryonic development, angiogenesis, and wound closure. h, Same cell as in d 2 min after BDM treatment. Notice the close correlation between force and total intensity, as both decrease with time. g, Time dependence of the relaxation of force and total intensity as a normalized average over all focal adhesions. f, Time dependence of the relaxation of force (red squares) and total GFP–vinculin intensity (black dots) of a single focal adhesion. Its slope defines a stress of 5.5 2 nN m-2 at the focal adhesions. The black line is the correlation line of the linear part of the plot. Each different symbol represents a different focal adhesion. e, Correlation between the area and force of the focal adhesions of the cell shown in d, at all time points. e–h, After the addition of 15 mM 2,3-butanedione monoxime (BDM). Inset: fluorescence image of the pattern of dots below the left-hand side of the cell green arrows denote displacements. The red arrows show the forces transmitted at the focal adhesions. d, Fluorescence image of a human foreskin fibroblast expressing GFP–vinculin, which localizes to the focal adhesions. Absence of error bars indicates an error below the size of the symbol. Each point represents a single focal adhesion from d. The angles (in radians) were measured relatively to the x axis of the pictures. c, Correlation between the direction of the force and the elongation of the focal adhesion. b, Correlation between force and total fluorescence intensity of single focal adhesions. a, Correlation between force and area of single focal adhesions. White scale bars represent 4 m red scale bars represent 30 nN.Ĭorrelation between force and focal adhesion structure.a–d, Before the addition of BDM. c, Phase-contrast image of the same cell immediately before fixation. Red arrows correspond to forces extracted from the displacements of the patterned elastomer (Young's modulus = 21 kPa) the pattern consists of small tips formed by electron-beam lithography (see j, 3). b, Fluorescence image of a human foreskin fibroblast stained with antibodies against paxillin, which also localizes at focal adhesions. Inset, phase-contrast image of the upper part of the cell (white rectangle), showing displacements of the dots (green arrows) the pattern consists of small square pits (see j, 1). Note the alignment of force with the direction of elongation of large focal adhesions. Red arrows correspond to forces extracted from the displacements of the patterned elastomer (Young's modulus = 18 kPa). Visualization of forces and focal adhesions.a, Fluorescence image of a human foreskin fibroblast expressing GFP–vinculin, which localizes to focal adhesions. The results put clear constraints on the possible molecular mechanisms for the mechanosensory response of focal adhesions to applied force. The dynamics of the force-dependent modulation of focal adhesions were characterized by blocking actomyosin contractility and were found to be on a time scale of seconds. Local forces are correlated with the orientation, total fluorescence intensity and area of the focal adhesions, indicating a constant stress of 5.5 +/- 2 nNmicrom(-2). This method combines micropatterning of elastomer substrates and fluorescence imaging of focal adhesions in live cells expressing GFP-tagged vinculin. A novel approach was developed for real-time, high-resolution measurements of forces applied by cells at single adhesion sites. In order to explore the molecular mechanism underlying this regulation, we have investigated the relationship between local force applied by the cell to the substrate and the assembly of focal adhesions. Mechanical forces play a major role in the regulation of cell adhesion and cytoskeletal organization.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |