title: A biomechanical model for fluidization of cells under dynamic strain.
abstract: Recent experiments have investigated the response of smooth muscle cells to transient stretch-compress (SC) and compress-stretch (CS) maneuvers. The results indicate that the transient SC maneuver causes a sudden fluidization of the cell while the CS maneuver does not. To understand this asymmetric behavior, we have built a biomechanical model to probe the response of stress fibers to the two maneuvers. The model couples the cross-bridge cycle of myosin motors with a viscoelastic Kelvin-Voigt element that represents the stress fiber. Simulation results point to the sensitivity of the myosin detachment rate to tension as the cause for the asymmetric response of the stress fiber to the CS and SC maneuvers. For the SC maneuver, the initial stretch increases the tension in the stress fiber and suppresses myosin detachment. The subsequent compression then causes a large proportion of the myosin population to disengage rapidly from actin filaments. This leads to the disassembly of the stress fibers and the observed fluidization. In contrast, the CS maneuver only produces a mild loss of myosin motors and no fluidization.
authors.affiliation: Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Tenghu
authors.initials: T
authors.lastname: Wu
authors.affiliation: Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia, Canada; Department of Mathematics, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: james.feng@ubc.ca.
authors.forename: James J
authors.initials: JJ
authors.lastname: Feng
mesh_terms: D000199:Actins / Q000378:metabolism; D003198:Computer Simulation; D055119:Elastic Modulus; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000502:physiology*; D009218:Myosins / Q000378:metabolism; D013314:Stress, Mechanical; D014783:Viscosity
chemical_list: D000199:Actins; D009218:Myosins