Physics Commons^™

Extracellular Vimentin Is Sufficient To Promote Cell Attachment, Spreading, And Motility By A Mechanism Involving N-Acetyl Glucosamine-Containing Structures, Robert Bucki, Daniel V. Iwamoto, Xuechen Shi, Katherine E. Kerr, Fitzroy J. Byfield, Lukasz Suprewicz, Karol Sklodowski, Julian Sutaria, Pawel Misiak, Agnieszka Z. Wilczewska, Sekar Ramachandran, Aaron Wolfe, Minh H. Thanh, Eli Whalen, Alison E. Patteson, Paul A. Janmey

Physics - All Scholarship

Vimentin intermediate !laments form part of the cytoskeleton

of mesenchymal cells, but under pathological conditions often

associatedwith in"ammation, vimentin !laments depolymerize as

the result of phosphorylation or citrullination, and vimentin

oligomers are secreted or released into the extracellular environment.

In the extracellular space, vimentin can bind surfaces of cells

and the extracellular matrix, and the interaction between extracellular

vimentin and cells can trigger changes in cellular functions,

such as activation of !broblasts to a !brotic phenotype. The

mechanism by which extracellular vimentin binds external cell

membranes and whether vimentin alone can act as an adhesive

anchor for cells is largely …

Vimentin Intermediate Filaments Mediate Cell Morphology On Viscoelastic Substrates, Maxx Swoger, Sarthak Gupta, Elisabeth E. Charrier, Michael Bates, Heidi Hehnly, Alison E. Patteson

Physics - All Scholarship

The ability of cells to take and change shape is a fundamental feature underlying development, wound repair, and tissue maintenance. Central to this process is physical and signaling interactions between the three cytoskeletal polymeric networks: F-actin, microtubules, and intermediate filaments (IFs). Vimentin is an IF protein that is essential to the mechanical resilience of cells and regulates cross-talk among the cytoskeleton, but its role in how cells sense and respond to the surrounding extracellular matrix is largely unclear. To investigate vimentin’s role in substrate sensing, we designed polyacrylamide hydrogels that mimic the elastic and viscoelastic nature of in vivo tissues. …

The Role Of Vimentin–Nuclear Interactions In Persistent Cell Motility Through Confined Spaces, Sarthak Gupta, Alison E. Patteson, J. M. Schwarz

Physics - All Scholarship

The ability of cells to move through small spaces depends on the mechanical properties of the cellular cytoskeleton and on nuclear deformability. In mammalian cells, the cytoskeleton is composed of three interacting, semi-flexible polymer networks: actin, microtubules, and intermediate filaments (IF). Recent experiments of mouse embryonic fibroblasts with and without vimentin have shown that the IF vimentin plays a role in confined cell motility. Here, we develop a minimal model of a cell moving through a microchannel that incorporates explicit effects of actin and vimentin and implicit effects of microtubules. Specifically, the model consists of a cell with an actomyosin …

Cell-Induced Confinement Effects In Soft Tissue Mechanics, Dawei Song, Jordan L. Shivers, Fred C. Mackintosh, Alison E. Patteson, Paul A. Janmey

Physics - All Scholarship

The mechanical properties of tissues play a critical role in their normal and pathophysiological functions such as tissue development, aging, injury, and disease. Understanding tissue mechanics is important not only for designing realistic biomimetic materials for tissue engineering and drug testing but also for developing novel diagnostic techniques and medical interventions. Tissues are heterogeneous materials consisting of cells confined within extracellular matrices (ECMs), both of which derive their structural integrity, at least in part, from networks of biopolymers. However, the rheology of purified reconstituted biopolymer networks fails to explain many key aspects of tissue mechanics. Notably, purified networks typically soften …

The Vimentin Cytoskeleton: When Polymer Physics Meets Cell Biology, Alison E. Patteson, Robert J. Carroll, Daniel V. Iwamoto, Paul A. Janmey

Physics - All Scholarship

The proper functions of tissues depend on the ability of cells to withstand stress and maintain shape. Central to this process is the cytoskeleton, comprised of three polymeric networks: F-actin, microtubules, and intermediate filaments (IFs). IF proteins are among the most abundant cytoskeletal proteins in cells; yet they remain some of the least understood. Their structure and function deviate from those of their cytoskeletal partners, F-actin and microtubules. IF networks show a unique combination of extensibility, flexibility and toughness that confers mechanical resilience to the cell. Vimentin is an IF protein expressed in mesenchymal cells. This review highlights exciting new …

Vimentin Protects Cells Against Nuclear Rupture And Dna Damage During Migration, Alison E. Patteson, Amir Vahabikashi, Katarzyna Pogoda, Stephen A. Adam, Kalpana Mandal, Mark Kittisopikul, Suganya Sivagurunathan, Anne Goldman, Robert D. Goldman, Paul A. Janmey

Physics - All Scholarship

Mammalian cells frequently migrate through tight spaces during normal embryogenesis, wound healing, diapedesis, or in pathological situations such as metastasis. Nuclear size and shape are important factors in regulating the mechanical properties of cells during their migration through such tight spaces. At the onset of migratory behavior, cells often initiate the expression of vimentin, an intermediate filament protein that polymerizes into networks extending from a juxtanuclear cage to the cell periphery. However, the role of vimentin intermediate filaments (VIFs) in regulating nuclear shape and mechanics remains unknown. Here, we use wild-type and vimentin-null mouse embryonic fibroblasts to show that VIFs …

Paraboloidal Crystals, Mark Bowick, Luca Giomi

Physics - All Scholarship

The interplay between order and geometry in soft condensed matter systems is an active field with many striking results and even more open problems. Ordered structures on curved surfaces appear in multi-electron helium bubbles, viral and bacteriophage protein capsids, colloidal self-assembly at interfaces and in physical membranes. Spatial curvature can lead to novel ground state configurations featuring arrays of topological defects that would be excited states in planar systems. We illustrate this with a sequence of images showing the Voronoi lattice (in gold) and the corresponding Delaunay triangulations (in green) for ten low energy configurations of a system of classical …

Sheared Active Fluids: Thickening, Thinning And Vanishing Viscosity, Luca Giomi, Tanniemola B. Liverpool, M. Cristina Marchetti

Physics - All Scholarship

We analyze the behavior of a suspension of active polar particles under shear. In the absence of external forces, orientationally ordered active particles are known to exhibit a transition to a state of non-uniform polarization and spontaneous flow. Such a transition results from the interplay between elastic stresses, due to the liquid crystallinity of the suspension, and internal active stresses. In the presence of an external shear we find an extremely rich variety of phenomena, including an effective reduction (increase) in the apparent viscosity depending on the nature of the active stresses and the flow-alignment property of the particles, as …