TY - JOUR
T1 - Validation of a new live cell strain system
T2 - Characterization of plasma membrane stress failure
AU - Stroetz, Randolph W.
AU - Vlahakis, Nicholas E.
AU - Walters, Bruce J.
AU - Schroeder, Mark A.
AU - Hubmayr, Rolf D.
PY - 2001/6
Y1 - 2001/6
N2 - Motivated by our interest in lung deformation injury, we report on the validation of a new live cell strain system. We showed that the system maintains a cell culture environment equivalent to that provided by conventional incubators and that its strain output was uniform and reproducible. With this system, we defined cell deformation dose (i.e., membrane strain amplitude)-cell injury response relationships in alveolar epithelial cultures and studied the effects of temperature on them. Deformation injury occurred in the form of reversible, nonlethal plasma membrane stress failure events and was quantified as the fraction of cells with uptake and retention of fluorescein-labeled dextran (FITC-Dx). The undeformed control population showed virtually no FITC-Dx uptake at any temperature, which was also true for cells strained by 3%. However, when the membrane strain was increased to 18%, ∼5% of cells experienced deformation injury at a temperature of 37°C. Moreover, at that strain, a reduction in temperature to 4°C resulted in a threefold increase in the number of cells with plasma membrane breaks (from 4.8 to 15.9%; P < 0.05). Cooling of cells to 4°C also lowered the strain threshold at which deformation injury was first seen. That is, at a 9% substratum strain, cooling to 4°C resulted in a 10-fold increase in the number of cells with FITC-Dx staining (0.7 vs. 7.5%, P < 0.05). At that temperature, A549 cells offered a 50% higher resistance to shape change (magnetic twisting cytometry measurements) than at 37°C. We conclude that the strain-injury threshold of A549 cells is reduced at low temperatures, and we consider temperature effects on plasma-membrane fluidity, cytoskeletal stiffness, and lipid trafficking as responsible mechanisms.
AB - Motivated by our interest in lung deformation injury, we report on the validation of a new live cell strain system. We showed that the system maintains a cell culture environment equivalent to that provided by conventional incubators and that its strain output was uniform and reproducible. With this system, we defined cell deformation dose (i.e., membrane strain amplitude)-cell injury response relationships in alveolar epithelial cultures and studied the effects of temperature on them. Deformation injury occurred in the form of reversible, nonlethal plasma membrane stress failure events and was quantified as the fraction of cells with uptake and retention of fluorescein-labeled dextran (FITC-Dx). The undeformed control population showed virtually no FITC-Dx uptake at any temperature, which was also true for cells strained by 3%. However, when the membrane strain was increased to 18%, ∼5% of cells experienced deformation injury at a temperature of 37°C. Moreover, at that strain, a reduction in temperature to 4°C resulted in a threefold increase in the number of cells with plasma membrane breaks (from 4.8 to 15.9%; P < 0.05). Cooling of cells to 4°C also lowered the strain threshold at which deformation injury was first seen. That is, at a 9% substratum strain, cooling to 4°C resulted in a 10-fold increase in the number of cells with FITC-Dx staining (0.7 vs. 7.5%, P < 0.05). At that temperature, A549 cells offered a 50% higher resistance to shape change (magnetic twisting cytometry measurements) than at 37°C. We conclude that the strain-injury threshold of A549 cells is reduced at low temperatures, and we consider temperature effects on plasma-membrane fluidity, cytoskeletal stiffness, and lipid trafficking as responsible mechanisms.
KW - Alveolar epithelial cells
KW - Biomechanics
KW - Cell physiology
KW - Ventilator-induced lung injury
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U2 - 10.1152/jappl.2001.90.6.2361
DO - 10.1152/jappl.2001.90.6.2361
M3 - Article
C2 - 11356803
AN - SCOPUS:0035008495
SN - 8750-7587
VL - 90
SP - 2361
EP - 2370
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 6
ER -