scholarly journals Loss of vimentin intermediate filaments decreases peri-nuclear stiffness and enhances cell motility through confined spaces

2018 ◽  
Author(s):  
Alison E. Patteson ◽  
Katarzyna Pogoda ◽  
Fitzroy J. Byfield ◽  
Elisabeth E. Charrier ◽  
Peter A. Galie ◽  
...  
Keyword(s):  
Cell Motility ◽  
Cancer Metastasis ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Large Strains ◽  
Mechanical Resistance ◽  
Intermediate Filament Protein ◽  
Migratory Cells ◽  
Filament Protein ◽  
Extracellular Matrix Receptors

The migration of cells through tight constricting spaces or along fibrous tracks in tissues is important for biological processes, such as embryogenesis, wound healing, and cancer metastasis, and depends on the mechanical properties of the cytoskeleton. Migratory cells often express and upregulate the intermediate filament protein vimentin. The viscoelasticity of vimentin networks in shear deformation has been documented, but its role in motility is largely unexplored. Here, we studied the effects of vimentin on cell motility and stiffness using mouse embryo fibroblasts derived from wild-type and vimentin-null mice. We find that loss of vimentin increases motility through small pores and along thin capillaries. Atomic force microscopy measurements reveal that the presence of vimentin enhances the perinuclear stiffness of the cell, to an extent that depends on surface ligand presentation and therefore signaling from extracellular matrix receptors. Together, our results indicate that vimentin hinders three-dimensional motility by providing mechanical resistance against large strains and may thereby protect the structural integrity of cells.

Supplementation of a mutant keratin by stable expression of desmin in cultured human EBS keratinocytes

2000 ◽  
Vol 113 (23) ◽  
pp. 4231-4239 ◽  
Author(s):  
T.M. Magin ◽  
H.W. Kaiser ◽  
S. Leitgeb ◽  
C. Grund ◽  
I.M. Leigh ◽  
...  
Keyword(s):  
Intermediate Filament ◽  
Structural Integrity ◽  
Basal Layer ◽  
Intermediate Filament Protein ◽  
Epidermolysis Bullosa Simplex ◽  
Autosomal Dominant Disorder ◽  
Keratin Filaments ◽  
Skin Fragility ◽  
Keratinocyte Cell ◽  
Filament Protein

Mutations in keratin genes give rise to a number of inherited skin fragility disorders, demonstrating that the intermediate filament cytoskeleton has an essential function in maintaining the structural integrity of epidermis and its appendages. Epidermolysis bullosa simplex (EBS) is an autosomal dominant disorder caused by mutations in keratins K5 or K14, which are expressed in the basal layer of stratified epithelia. Using a keratinocyte cell line established from an EBS patient, we investigated whether the muscle-specific intermediate filament protein desmin would be able to functionally complement a mutant keratin 14 in cultured keratinocytes. We show that in stably transfected EBS cells, desmin forms an extended keratin-independent cytoskeleton. Immunogold-EM analysis demonstrated that in the presence of numerous keratin filaments attached to desmosomes, desmin could nevertheless interact with desmosomes in the same cell, indicating the dynamic nature of the filament-desmosome association. When desmin-transfected cells were subjected to heat shock, the mutant keratin filaments showed a transient collapse while desmin filaments were maintained. Thus the defective keratin filaments and the wild-type desmin filaments appear to coexist in cells without interference. Expression of a type III intermediate filament protein like desmin may offer a strategy for the treatment of patients suffering from epidermal keratin mutations.

scholarly journals Recovery of Tractions Exerted by Single Cells in Three-Dimensional Nonlinear Matrices

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Dawei Song ◽  
Li Dong ◽  
Mukund Gupta ◽  
Linqing Li ◽  
Ottmar Klaas ◽  
...  
Keyword(s):  
Cancer Metastasis ◽  
Single Cells ◽  
Three Dimensional ◽  
Traction Force ◽  
Simulated Data ◽  
Nonlinear Effects ◽  
Stem Cell Differentiation ◽  
Large Strains ◽  
The Matrix ◽  
Minimization Procedure

Abstract Cell-generated tractions play an important role in various physiological and pathological processes such as stem-cell differentiation, cell migration, wound healing, and cancer metastasis. Traction force microscopy (TFM) is a technique for quantifying cellular tractions during cell–matrix interactions. Most applications of this technique have heretofore assumed that the matrix surrounding the cells is linear elastic and undergoes infinitesimal strains, but recent experiments have shown that the traction-induced strains can be large (e.g., more than 50%). In this paper, we propose a novel three-dimensional (3D) TFM approach that consistently accounts for both the geometric nonlinearity introduced by large strains in the matrix, and the material nonlinearity due to strain-stiffening of the matrix. In particular, we pose the TFM problem as a nonlinear inverse hyperelasticity problem in the stressed configuration of the matrix, with the objective of determining the cellular tractions that are consistent with the measured displacement field in the matrix. We formulate the inverse problem as a constrained minimization problem and develop an efficient adjoint-based minimization procedure to solve it. We first validate our approach using simulated data, and quantify its sensitivity to noise. We then employ the new approach to recover tractions exerted by NIH 3T3 cells fully encapsulated in hydrogel matrices of varying stiffness. We find that neglecting nonlinear effects can induce significant errors in traction reconstructions. We also find that cellular tractions roughly increase with gel stiffness, while the strain energy appears to saturate.

Immunocytochemical localization of desmin and vimentin in chick embryonic myocardial cells

1990 ◽  
Vol 48 (3) ◽  
pp. 448-449
Author(s):  
Yukiko Sugi
Keyword(s):  
Sodium Methoxide ◽  
Intermediate Filament Protein ◽  
Chick Embryos ◽  
Immunocytochemical Localization ◽  
Myocardial Cells ◽  
Immunofluorescence Study ◽  
Immunofluorescent Localization ◽  
Rabbit Igg ◽  
Semithin Sections ◽  
Filament Protein

In cultured skeletal muscle cells of chick, one intermediate filament protein, vimentin, is primarily formed and then synthesis of desmin follows. Coexistence of vimentin and desmin has been immunocytochemically confirmed in chick embryonic skeletal musclecells. Immunofluorescent localization of vimentin and desmin has been described in developing myocardial cells of hamster. However, initial localization of desmin and vimentin in early embryonic heart has not been reported in detail. By quick-freeze deep-etch method a loose network of intermediate filaments was revealed to exist surrounding myofibrils. In this report, immunocytochemical localization of desmin and vimentin is visualized in early stages of chick embryonic my ocardium.Chick embryos, Hamburger-Hamilton (H-H) stage 8 to hatch, and 1 day old postnatal chicks were used in this study. For immunofluorescence study, each embryo was fixed with 4% paraformaldehyde and embedded in Epon 812. De-epoxinized with sodium methoxide, semithin sections were stained with primary antibodies (rabbit anti-desmin antibody and anti-vimentin antibody)and secondary antibody (RITC conjugated goat-anti rabbit IgG).

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