Adhesion-free cell migration by topography-based force transduction

AbstractEukaryotic cells migrate by coupling the intracellular force of the actin cytoskeleton to the environment. While force-coupling is usually mediated by transmembrane adhesion receptors, especially these of the integrin family, amoeboid cells like leukocytes can migrate extremely fast despite very low adhesive forces1. We show that leukocytes cannot only migrate under low adhesion but indeed can transduce forces in the complete absence of transmembrane force coupling. When confined within three-dimensional environments, they use the topographic features of the substrate to propel themselves. Here, the retrograde flow of the actin cytoskeleton follows the texture of the substrate, creating shear forces sufficient to drive deformations towards the back of the cell. Notably, adhesion dependent and adhesion independent migration are not exclusive but rather variants of the same principle of coupling retrograde actin flow to the environment and thus can potentially operate simultaneously. As adhesion free migration is independent of the chemical composition of the environment it renders cells completely autonomous in their locomotive behavior.

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Faculty Opinions recommendation of Direct comparisons of the morphology, migration, cell adhesions, and actin cytoskeleton of fibroblasts in four different three-dimensional extracellular matrices.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.7737956.8067055 ◽

2011 ◽

Author(s):

Alan Rick Horwitz

Keyword(s):

Actin Cytoskeleton ◽

Three Dimensional ◽

Extracellular Matrices ◽

Cell Adhesions

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Composite hollow truss with multiple vierendeel panels

Rem Revista Escola de Minas ◽

10.1590/s0370-44672013000400005 ◽

2013 ◽

Vol 66 (4) ◽

pp. 431-438

Author(s):

Augusto Ottoni Bueno da Silva ◽

Newton de Oliveira Pinto Júnior ◽

João Alberto Venegas Requena

Keyword(s):

Bearing Capacity ◽

Failure Modes ◽

Three Dimensional ◽

Analytical Calculation ◽

Two Dimensional ◽

Shear Forces ◽

Vertical Displacements ◽

New System ◽

The Ideal

The aim of this study was to evaluate through analytical calculation, two-dimensional elastic modeling, and three-dimensional plastic modeling, the bearing capacity and failure modes of composite hollow trusses bi-supported with a 15 meter span, varying the number of central Vierendeel panels. The study found the proportion span/3 - span/3 - span/3, as the ideal relationship for the truss - Vierendeel - truss lengths, because by increasing the proportion of the length occupied by the central Vierendeel panels, the new system loses stiffness and no longer supports the load stipulated in the project. Furthermore, they can start presenting excessive vertical displacements and insufficient resistance to external shear forces acting on the panels.

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Energetics of Barotropic and Baroclinic Tides in the Monterey Bay Area

Journal of Physical Oceanography ◽

10.1175/jpo-d-11-039.1 ◽

2012 ◽

Vol 42 (2) ◽

pp. 272-290 ◽

Cited By ~ 84

Author(s):

Dujuan Kang ◽

Oliver Fringer

Keyword(s):

Energy Flux ◽

Three Dimensional ◽

Internal Tide ◽

Submarine Canyon ◽

Tidal Energy ◽

Energy Partitioning ◽

Navier Stokes ◽

Monterey Bay ◽

Topographic Features ◽

Bay Area

Abstract A detailed energy analysis of the barotropic and baroclinic M2 tides in the Monterey Bay area is performed. The authors first derive a theoretical framework for analyzing internal tide energetics based on the complete form of the barotropic and baroclinic energy equations, which include the full nonlinear and nonhydrostatic energy flux contributions as well as an improved evaluation of the available potential energy. This approach is implemented in the Stanford Unstructured Nonhydrostatic Terrain-Following Adaptive Navier–Stokes Simulator (SUNTANS). Results from three-dimensional, high-resolution SUNTANS simulations are analyzed to estimate the tidal energy partitioning among generation, radiation, and dissipation. A 200 km × 230 km domain including all typical topographic features in this region is used to represent the Monterey Bay area. Of the 152-MW energy lost from the barotropic tide, approximately 133 MW (88%) is converted into baroclinic energy through internal tide generation, and 42% (56 MW) of this baroclinic energy radiates away into the open ocean. The tidal energy partitioning depends greatly on the topographic features. The Davidson Seamount is most efficient at baroclinic energy generation and radiation, whereas the Monterey Submarine Canyon acts as an energy sink. Energy flux contributions from nonlinear and nonhydrostatic effects are also examined. In the Monterey Bay area, the nonlinear and nonhydrostatic contributions are quite small. Moreover, the authors investigate the character of internal tide generation and find that in the Monterey Bay area the generated baroclinic tides are mainly linear and in the form of internal tidal beams. Comparison of the modeled tidal conversion to previous theoretical estimates shows that they are consistent with one another.

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The Effect of Lifting vs. Lowering on Spinal Loading

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/154193129604001304 ◽

1996 ◽

Vol 40 (13) ◽

pp. 599-603 ◽

Cited By ~ 1

Author(s):

Kermit G. Davis

Keyword(s):

Muscle Activity ◽

Dimensional Space ◽

Three Dimensional ◽

Muscle Forces ◽

Shear Forces ◽

Spinal Loading ◽

Spinal Loads ◽

Trunk Strength ◽

Anterior Posterior ◽

Three Dimensional Space

In industry, workers perform tasks requiring both lifting and lowering. During concentric lifting, the muscles are shortening as the force is being generated. Conversely, the muscle lengthens while generating force during eccentric lowering. While research on various lifting tasks is extensive, there has been limited research performed to evaluate the lowering tasks. Most of the research that does exist on lowering has investigated muscle activity and trunk strength. None of these studies have investigated spinal loading. The current study estimated the effects of lifting and lowering on spinal loads and predicted moments imposed on the spine. Ten subjects performed both eccentric and concentric lifts under sagittally symmetric conditions. The tasks were performed under isokinetic trunk velocities of 5, 10, 20, 40, and 80 deg/s while holding a box with weights of 9.1, 18.2, and 27.3 kg. Spinal loads and predicted moments in three dimensional space were estimated by an EMG-assisted model which has been adjusted to incorporate the artifacts of eccentric lifting. Eccentric strength was found to be 56 percent greater than during concentric lifting. The lowering tasks produced significantly higher compression forces but lower anterior-posterior shear forces than the concentric lifting tasks. The differences in the spinal loads between the two lifting tasks were attributed to the internal muscle forces and unequal moments resulting from differences in the lifting path of the box. Thus, the differences between the lifting tasks resulted from different lifting styles associated with eccentric and concentric movements

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Biomechanics of shear-sensitive adhesion in climbing animals: peeling, pre-tension and sliding-induced changes in interface strength

10.1101/031773 ◽

2015 ◽

Author(s):

David Labonte ◽

Walter Federle

Keyword(s):

Linear Increase ◽

Shear Forces ◽

Rapid Control ◽

Stick Insects ◽

Direction Dependence ◽

Peel Force ◽

Rapid Switching ◽

Induced Changes ◽

Interfacial Mobility ◽

Adhesive Forces

Rapid control of adhesive forces is one of the key benchmarks where footpads of climbing animals outperform conventional adhesives, promising novel bio-inspired attachment systems. All climbing animals use shear forces to switch rapidly between firm attachment and easy detachment, but the detailed mechanisms underlying `shear-sensitive adhesion' have remained unclear. Here, we show that attachment forces of stick insects follow classic peeling theory when shear forces are small, but strongly exceed predictions as soon as their pads start to slide due to high shear forces. Pad sliding dramatically increases the critical peel force via a combination of two distinct mechanisms. First, partial sliding will pre-stretch the pads, so that they are effectively stiffer upon detachment and peel increasingly like inextensible tape. We demonstrate how this effect can be directly related to peeling theories which account for frictional dissipation. Second, pad sliding reduces the thickness of the secretion layer in the contact zone, thereby decreasing the interfacial mobility, and increasing the stress levels required for peeling. The approximately linear increase of adhesion with friction results in a sharp increase of adhesion at peel angles less than ca. 30°, allowing rapid switching between attachment and detachment during locomotion. Our results may apply to diverse climbing animals independent of pad morphology and adhesive mechanism, and highlight that control of adhesion is not solely achieved by direction-dependence and morphological anisotropy, suggesting promising new routes for the development of bio-inspired adhesives.

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Regulated Actin Cytoskeleton Assembly at Filopodium Tips Controls Their Extension and Retraction

The Journal of Cell Biology ◽

10.1083/jcb.146.5.1097 ◽

1999 ◽

Vol 146 (5) ◽

pp. 1097-1106 ◽

Cited By ~ 257

Author(s):

Aneil Mallavarapu ◽

Tim Mitchison

Keyword(s):

Actin Cytoskeleton ◽

Growth Cone ◽

Actin Filaments ◽

Neuroblastoma Cell ◽

Initial Step ◽

Growth Cones ◽

Neuroblastoma Cell Line ◽

Dominant Factor ◽

Retrograde Flow ◽

Assembly Rate

The extension and retraction of filopodia in response to extracellular cues is thought to be an important initial step that determines the direction of growth cone advance. We sought to understand how the dynamic behavior of the actin cytoskeleton is regulated to produce extension or retraction. By observing the movement of fiduciary marks on actin filaments in growth cones of a neuroblastoma cell line, we found that filopodium extension and retraction are governed by a balance between the rate of actin cytoskeleton assembly at the tip and retrograde flow. Both assembly and flow rate can vary with time in a single filopodium and between filopodia in a single growth cone. Regulation of assembly rate is the dominant factor in controlling filopodia behavior in our system.

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Three Dimensional Traction Forces Exerted by Migrating Amoeboid Cells

Biophysical Journal ◽

10.1016/j.bpj.2011.11.3822 ◽

2012 ◽

Vol 102 (3) ◽

pp. 704a

Author(s):

Begona Alvarez-Gonzalez ◽

Juan C. del Alamo ◽

Ruedi Meili ◽

Baldomero Alonso-Latorre ◽

Richard Firtel ◽

...

Keyword(s):

Three Dimensional ◽

Traction Forces ◽

Amoeboid Cells

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Three-dimensional organization of actin cytoskeleton and podosomal contact structures in neoplastic cells in vitro

EBO — Experimental Biology Online Annual 1996/97 ◽

10.1007/978-3-662-00932-1_16 ◽

1998 ◽

pp. 219-243

Author(s):

Pavel Vesely ◽

Luboslava Pavlikova ◽

Jiri Plachy ◽

Katerina Trejbalova ◽

Jiri Hejnar ◽

...

Keyword(s):

Actin Cytoskeleton ◽

Three Dimensional ◽

Contact Structures ◽

Neoplastic Cells

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Morphological prediction of glaucoma by quantitative analyses of ocular shape and volume using 3-dimensional T2-weighted MR images

Scientific Reports ◽

10.1038/s41598-019-51611-0 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Yasuko Tatewaki ◽

Tatsushi Mutoh ◽

Kazuko Omodaka ◽

Benjamin Thyreau ◽

Izumi Matsudaira ◽

...

Keyword(s):

Axial Length ◽

Spin Echo ◽

Three Dimensional ◽

Spherical Shape ◽

Anisotropy Ratio ◽

Mr Images ◽

3.0 Tesla ◽

3 Dimensional ◽

Topographic Features ◽

Quantitative Analyses

Abstract Elongated axial length of the eye increases the morbidity of glaucoma. Myopia also associates with elongated axial length, and such ellipsoid shape of the eyeball strongly contributes its pathogenesis. Morphological features of the eyeballs, which could be important factors for developing glaucoma, have not been well described. The aim of this study was to investigate the three-dimensional (3D) topographic features of glaucomatous eyeballs with/without myopia to evaluate the potential of those features for predicting glaucoma. Using a 3.0-tesla MRI, volume-isotropic turbo-spin-echo acquisition T2-weighted images were obtained from 55 patients with glaucoma and 22 controls to delineate the eyeballs. Eyeball volumes, axial lengths and transverse lengths were semi-automatically calculated and compared between four groups: normal, myopia, glaucoma, and glaucoma with myopia. Both glaucoma and myopia increased the eyeball volume compared to the normal eyes. An increased anisotropy ratio (axial/transversus length) was observed in myopic eyes compared to normal, whereas in the glaucomatous eyes, with or without myopia, no increase in anisotropy ratio was observed. Increasing volume of eyes can be caused by myopia and glaucoma. Myopic eyes were ellipsoid in shape, but there was less anisotropy and a near-spherical shape in glaucomatous eyes, even in glaucomatous myopic eyes.

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