Mg2+ modulates integrin–extracellular matrix interaction in vascular smooth muscle cells studied by atomic force microscopy

Authors

  • Andreea Trache,

    Corresponding author
    1. Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA
    2. Department of Biomedical Engineering, Texas A&M University, College Station, TX 77840, USA
    • 336 Reynolds Medical Bldg., MS 1114, Texas A&M Health Science Center, College Station, TX 77843-1114, USA.
    Search for more papers by this author
  • Jerome P. Trzeciakowski,

    1. Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA
    Search for more papers by this author
  • Gerald A. Meininger

    1. Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology, University of Missouri, 134 Research Park Dr., Columbia, MO 65211, USA
    Search for more papers by this author

Abstract

Atomic force microscopy (AFM) was used to investigate the interaction between α5β1 integrin and fibronectin (FN) in the presence of divalent cations. AFM probes were labeled with FN and used to measure binding strength between α5β1 integrin and FN by quantifying the force required to break single FN–integrin bonds on a physiological range of loading rates (100–10 000 pN/s). The force necessary to rupture single α5β1–FN bond increased twofold over the regime of loading rates investigated. Changes in Mg2+ and Ca2+ concentration affected the thermodynamical parameters of the interaction and modulated the binding energy. These data indicate that the external ionic environment in which vascular smooth muscle cells reside, influences the mechanical parameters that define the interaction between the extracellular matrix and integrins. Thus, in a dynamic mechanical environment such as the vascular wall, thermodynamic binding properties between FN and α5β1 integrin vary in relation to locally applied loads and divalent cations concentrations. These changes can be recorded as direct measurements on live smooth muscle cells by using AFM. Copyright © 2009 John Wiley & Sons, Ltd.

Ancillary