Cytoskeletal mechanics in adherent human airway smooth muscle cells: probe specificity and scaling of protein-protein dynamics

• Published in: American Journal of Physiology: Cell Physiology 2004-09, Vol.287 (3), p.C643-C654
• Main Authors: Puig-de-Morales, Marina, Millet, Emil, Fabry, Ben, Navajas, Daniel, Wang, Ning, Butler, James P, Fredberg, Jeffrey J
• Format: Article
• Language: English
• Subjects: Acetylation; Cell Adhesion - physiology; Cells, Cultured; Cytoskeleton - physiology; Elasticity; Humans; Integrin beta Chains - metabolism; Ligands; Lipoproteins, LDL - metabolism; Microscopy, Electron, Scanning; Microspheres; Models, Biological; Myocytes, Smooth Muscle - physiology; Myocytes, Smooth Muscle - ultrastructure; Oligopeptides - metabolism; Protein Binding - physiology; Stress, Mechanical; Trachea - physiology; Urokinase-Type Plasminogen Activator - metabolism; Viscosity; Vitronectin - metabolism
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00070.2004

1 Physiology Program, Harvard School of Public Health, Boston, Massachusetts 02115; 2 Physics Department, Erlangen University, 91054 Erlangen, Germany; and 3 Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona 08036, Spain Submitted 5 February 2004 ; accepted in final form 5 May 2004 We probed elastic and loss moduli in the adherent human airway smooth muscle cell through a variety of receptor systems, each serving as a different molecular window on cytoskeletal dynamics. Coated magnetic microbeads were attached to the cell surface via coating-receptor binding. A panel of bead coatings was investigated: a peptide containing the sequence RGD, vitronectin, urokinase, activating antibody against 1 -integrin, nonactivating antibody against 1 -integrin, blocking antibody against 1 -integrin, antibody against 1 -integrin, and acetylated low-density lipoprotein. An oscillatory mechanical torque was applied to the bead, and resulting lateral displacements were measured at baseline, after actin disruption by cytochalasin D, or after contractile activation by histamine. As expected, mechanical moduli depended strongly on bead type and bead coating, differing at the extremes by as much as two orders of magnitude. In every case, however, elastic and loss moduli increased with frequency f as a weak power law, f x –1 . Moreover, with few exceptions, data could be scaled such that elastic and frictional responses depended solely on the power law exponent x . Taken together, these data suggest that power law behavior represents a generic feature of underlying protein-protein dynamics. actin; cytoskeleton; magnetic twisting cytometry; scale free; viscoelasticity Address for reprint requests and other correspondence: M. Puig-de-Morales, Physiology Program, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115 (E-mail: mpuigdem{at}hsph.harvard.edu ).