Cell prestress. I. Stiffness and prestress are closely associated in adherent contractile cells.
The tensegrity hypothesis holds that the cytoskeleton is a structure whose shape is stabilized predominantly by the tensile stresses borne by filamentous structures. Accordingly, cell stiffness must increase in proportion with the level of the tensile stress, which is called the prestress. Here we have tested that prediction in adherent human airway smooth muscle (HASM) cells. Traction microscopy was used to measure the distribution of contractile stresses arising at the interface between each cell and its substrate; this distribution is called the traction field. Because the traction field must be balanced by tensile stresses within the cell body, the prestress could be computed. Cell stiffness (G) was measured by oscillatory magnetic twisting cytometry. As the contractile state of the cell was modulated with graded concentrations of relaxing or contracting agonists (isoproterenol or histamine, respectively), the mean prestress ((t)) ranged from 350 to 1,900 Pa. Over that range, cell stiffness increased linearly with the prestress: G (Pa) = 0.18(t) + 92. While this association does not necessarily preclude other interpretations, it is the hallmark of systems that secure shape stability mainly through the prestress. Regardless of mechanism, these data establish a strong association between stiffness of HASM cells and the level of tensile stress within the cytoskeleton.
Wang
Ning
N
Physiology Program, Department of Environmental Health, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA. nwang@hsph.harvard.edu
Tolić-Nørrelykke
Iva Marija
IM
Chen
Jianxin
J
Mijailovich
Srboljub M
SM
Butler
James P
JP
Fredberg
Jeffrey J
JJ
Stamenović
Dimitrije
D
D000180:Acrylic Resins / Q000737:chemistry; D000199:Actins / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000502:physiology*; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D013314:Stress, Mechanical; D013718:Tensile Strength
D000180:Acrylic Resins; D000199:Actins; C016680:polyacrylamide gels; D006632:Histamine; D007545:Isoproterenol