Spatial patterns of cellular growth generate mechanical stresses that help to push, fold, expand, and deform tissues into their specific forms. Genetic factors are thought specify other behaviors drive morphogenesis. Here, we show tissue form itself can feed back regulate proliferation. Using micro-fabrication control the organization sheets cells, demonstrated emergence stable proliferative foci. Regions concentrated corresponded regions high tractional stress generated within sheet, as...

Protrusions are deformations that form at the surface of living cells during biological activities such as cell migration. Using combined optical tweezers and fluorescent microscopy, we quantified mechanical properties protrusions in adherent human embryonic kidney response to application an external force surface. The were analyzed by obtaining associated force-length plots protrusion formation, relaxation constant length. Protrusion mechanics interpretable a standard linear solid (Kelvin)...

Endothelial cells possess a mechanical network connecting adhesions on the basal surface, cytoskeleton, and nucleus. Transmission of force at via this pathway can deform nucleus, ultimately resulting in an alteration gene expression other cellular changes (mechanotransduction). Previously, we measured cell adhesion area apparent nuclear stretch during endothelial rounding. Here, reconstruct stress map nucleus from observed strains using finite-element modeling. To simulate disruption...

We investigated the mechanotransduction pathway in endothelial cells between their nucleus and adhesions to extracellular matrix. First, we measured nuclear deformations response alterations of cell shape as detach from a flat surface. found that deformation appeared be direct immediate adhesion area. The was then treated neo-Hookean compressible material, estimated stress associated with cytoskeleton acting on during rounding. With obtained field, magnitude forces deforming nucleus....

Tissue engineering is a promising therapeutic strategy to regenerate skeletal muscle. However, ex vivo cultivation methods typically result in low differentiation efficiency of stem cells as well grafts that resemble the native tissues morphologically, but lack contractile function. The application biomimetic tensile strain provides potent stimulus for enhancing myogenic and functional muscle grafts. We reviewed integrin-dependent mechanisms potentially link mechanotransduction pathways...

Abstract Ribbon is a nuclear Broad Tramtrack Bric‐a‐brac (BTB) ‐domain protein required for morphogenesis of the salivary gland and trachea. We recently showed that ribbon mutants exhibit decreased Crumbs Rab11‐coincident apical vesicles increased Moesin activity microvillar structure during tube elongation. To learn how these molecular morphological changes affect dynamics tubulogenesis, we optimized an advanced two‐photon microscope to enable high‐resolution live imaging Live revealed...

The low-pass voltage response of outer hair cells predicted by conventional equivalent circuit analysis would preclude the active force production at high frequencies. We have found that band pass characteristics can be improved introducing piezoelectric properties cell wall. In contrast to analysis, receptor potential does not tend zero and any frequency is greater than a limiting value. addition, phase shift between transduction current tends zero. cause an additional, strain-dependent,...

The mechanical properties of the lateral wall guinea pig cochlear outer hair cell were studied using micropipette aspiration technique. A fire-polished with an inner diameter approximately 4 microm was brought into contact and negative pressure applied. resulting deformation recorded on videotape subjected to morphometric analysis. relation between length aspirated portion is characterized by stiffness parameter, K(s) = 1.07 +/- 0.24 (SD) dyn/cm (n 14). Values do not correlate original...

The outer hair cell makes both passive and active contributions to basilar membrane mechanics. mechanics is strongly coupled the elastic properties of lateral wall. wall experiences in-plane deformations bending under physiological experimental conditions. To characterize wall, model an orthotropic cylindrical shell used. constants are estimated by solving a set three equations based on analyses independent experiments. first equation derived from new interpretation micropipet experiment;...

The electrical properties of the cellular membrane are important for ion transport across cells and electrophysiology. Plasma membranes also resist bending stretching, mechanical influence cell shape forces in tethers pulled from cells. There exists a coupling between membrane. Previous work has shown that applied voltages can induce movements lipid bilayer. We present theory computes deformations as voltage is changed. discover electromechanical bilayers depends on voltage-dependent...

The process of stem cell myogenesis (transformation into skeletal muscle cells) includes several stages characterized by the expression certain combinations myogenic factors. first part this is accompanied division, while second mainly associated with direct differentiation. mechanical cues are known to enhance myogenesis, and paper focuses on differentiation under condition externally applied strain. interpreted as interplay among transcription factors, targeted proteins strain-generated...

Adipose-derived stem cells (ASCs) are clinically important in regenerative medicine as they relatively easy to obtain, characterized by low morbidity, and can differentiate into myogenic progenitor cells. Although studies have elucidated the principal markers, PAX7, Desmin, MyoD, MHC, underlying mechanisms not completely understood. This motivates application of computational methods facilitate greater understanding such processes. In following, we present a multi-stage kinetic model...

We analyze the nonlinear behavior of longitudinal and circumferential components active force generated by outer hair cell wall in response to changes its transmembrane potential. treat material as electroelastic, linear orthotropic terms strains To describe versus potential, we use two (Boltzmann simple exponential) types approximation. estimate free parameters these approximations combining previously reported passive stiffnesses with measured microchamber experiment. sensitivity estimated...

Outer hair cells are critical to the amplification and frequency selectivity of mammalian ear acting via a fine mechanism called cochlear amplifier, which is especially effective in high-frequency region cochlea. How this works under physiological conditions how these overcome viscous (mechanical) electrical (membrane) filtering has yet be fully understood. electromotile, they strategically located cochlea generate an active force amplifying basilar membrane vibration. To investigate cell's...

Tethers are thin membrane tubes that can be formed when relatively small and localized forces applied to cellular membranes lipid bilayers. Tether pulling experiments have been used better understand the fine properties. These include interaction between plasma underlying cytoskeleton, which is an important factor affecting mechanics. We use a computational method aimed at interpretation design of tether in cells with strong membrane-cytoskeleton attachment. In our model, we take into...

Mathematical (computational) modeling approaches can be effective tools in providing insight into cell-fate decisions. In this article, several major to the of embryonic, hematopoietic, adipose-derived, cancer, and neural stem cell differentiation are discussed. First, population dynamics approach is considered. The models described as bifurcating dynamical systems that result bistability or periodic oscillations then Also, spatiotemporal differentiation, including continuum discrete (agent-...