Dominik R. Haudenschild^∗,†, Jianfen Chen^∗,†, Nikolai Steklov^†, Martin K. Lotz^*, Darryl D. D’Lima^∗,‡

Molecular & Cellular Biomechanics, Vol.6, No.3, pp. 135-144, 2009, DOI:10.3970/mcb.2009.006.135

Abstract The actin cytoskeleton is a dynamic network required for intracellular transport, signal transduction, movement, attachment to the extracellular matrix, cellular stiffness and cell shape. Cell shape and the actin cytoskeletal configuration are linked to chondrocyte phenotype with regard to gene expression and matrix synthesis. Historically, the chondrocyte actin cytoskeleton has been studied after formaldehyde fixation - precluding real-time measurements of actin dynamics, or in monolayer cultured cells. Here we characterize the actin cytoskeleton of living low-passage human chondrocytes grown in three-dimensional culture using a stably expressed actin-GFP construct. GFP-actin expression does not substantially alter the production of endogenous actin at… More >

Colin K. Choi^*, Brian P. Helmke^∗,†

Molecular & Cellular Biomechanics, Vol.5, No.4, pp. 247-258, 2008, DOI:10.3970/mcb.2008.005.247

Abstract Hemodynamic shear stress guides a variety of endothelial phenotype characteristics, including cell morphology, cytoskeletal structure, and gene expression profile. The sensing and processing of extracellular fluid forces may be mediated by mechanotransmission through the actin cytoskeleton network to intracellular locations of signal initiation. In this study, we identify rapid actin-mediated morphological changes in living subconfluent and confluent bovine aortic endothelial cells (ECs) in response to onset of unidirectional steady fluid shear stress (15 dyn/cm²). After flow onset, subconfluent cells exhibited dynamic edge activity in lamellipodia and small ruffles in the downstream and side directions for the first 12 min; activity… More >

Anat Ratnovsky^∗,†, Matthew Mellema^*, Steven S. An^∗,‡, Jeffrey J. Fredberg^*, Stephanie A. Shore^*

Molecular & Cellular Biomechanics, Vol.4, No.3, pp. 143-158, 2007, DOI:10.3970/mcb.2007.004.143

Abstract Obesity is a risk factor for asthma. The purpose of this study was to determine whether metformin, an agent used in the treatment of an obesity-related condition (type II diabetes), might have therapeutic potential for modifying the effects of obesity on airway smooth muscle (ASM) function. Metformin acts via activation of AMP-activated protein kinase (AMPK), a cellular sensor of energy status. In cultured murine ASM cells, metformin (0.2--2 mM) caused a dose-dependent inhibition of cell proliferation induced by PDGF (10^-8 M) and serotonin (10^-4 M). Another AMPK activator, 5-aminoimidazole-4-carboxamide-1-ß-D-riboruranoside (AICAR), also inhibited PDGF-induced proliferation. Furthermore, cells treated with metformin or… More >

Judith Su^∗, Xingyu Jiang^†, Roy Welsch^‡, George M. Whitesides^§, Peter T. C. So^¶

Molecular & Cellular Biomechanics, Vol.4, No.2, pp. 87-104, 2007, DOI:10.3970/mcb.2007.004.087

Abstract Interactions between the cell and the extracellular matrix regulate a variety of cellular properties and functions, including cellular rheology. In the present study of cellular adhesion, area was controlled by confining NIH 3T3 fibroblast cells to circular micropatterned islands of defined size. The shear moduli of cells adhering to islands of well defined geometry, as measured by magnetic microrheometry, was found to have a significantly lower variance than those of cells allowed to spread on unpatterned surfaces. We observe that the area of cellular adhesion influences shear modulus. Rheological measurements further indicate that cellular shear modulus is a biphasic function… More >

Konstantinos A. Lazopoulos¹, Dimitrije Stamenović²

Molecular & Cellular Biomechanics, Vol.3, No.1, pp. 43-48, 2006, DOI:10.3970/mcb.2006.003.043

Abstract It is well documented that in response to substrate stretching adhering cells alter their orientation. Generally, the cells reorient away from the direction of the maximum substrate strain, depending upon the magnitude of the substrate strain and the state of cell contractility. Theoretical models from the literature can describe only some aspects of this phenomenon. In the present study, we developed a more comprehensive mathematical model of cell reorientation than the current models. Using the framework of theory of non-linear elasticity, we found that the problem of cell reorientation was a stability problem, with the global (Maxwell's) criterion for stability.… More >

E. P. Yalcintas¹, J. Hu¹, Y. Liu^1,2, A. Voloshin^1,2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.2, pp. 151-180, 2014, DOI:10.3970/cmes.2014.098.151

Abstract Mechanical behavior of cells plays a crucial role in response to external stimuli and environment. It is very important to elucidate the mechanisms of cellular activities like spreading and alignment as it would shed light on further biological concepts. In this study, a multi-scale computational approach is adopted by modeling the cytoskeleton of cell as a tensegrity structure. The model is based on the complementary force balance between the tension and compression elements, resembling the internal structure of cell cytoskeleton composed of microtubules and actin filaments. The effect of surface topology on strain energy of a spread cell is investigated… More >