Journal of Cellular Biochemistry

Osteoblast Adhesion Dynamics: A Possible Role for ROS and LMW-PTP

Authors

  • Gustavo V. O. Fernandes,

    1. Antonio Pedro University Hospital, Fluminense Federal University, Niterói, RJ, Brazil
    Search for more papers by this author
  • Alexandre D. M. Cavagis,

    1. Universidade Federal de São Carlos, Campus Sorocaba, Sorocaba, SP, Brazil
    Search for more papers by this author
  • Carmen V. Ferreira,

    1. Departamento de Bioquímica, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
    Search for more papers by this author
  • Beni Olej,

    1. Antonio Pedro University Hospital, Fluminense Federal University, Niterói, RJ, Brazil
    Search for more papers by this author
  • Maurício de Souza Leão,

    1. Antonio Pedro University Hospital, Fluminense Federal University, Niterói, RJ, Brazil
    Search for more papers by this author
  • Cláudia L. Yano,

    1. Departamento de Bioquímica, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
    Search for more papers by this author
  • Maikel Peppelenbosch,

    1. Department of Cell Biology, University of Groningen, Groningen, The Netherlands
    Search for more papers by this author
  • José Mauro Granjeiro,

    1. Antonio Pedro University Hospital, Fluminense Federal University, Niterói, RJ, Brazil
    2. Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO), Diretoria de Programas (DIPRO)/Bioengenharia, Xerém, RJ, Brazil
    Search for more papers by this author
  • Willian F. Zambuzzi

    Corresponding author
    1. Laboratório de Bioensaios e Dinâmica Celular, Dept. Chemistry and Biochemistry, Biosciences Institute, UNESP, Botucatu, Sao Paulo, Brazil
    • Correspondence to: Willian F. Zambuzzi, PhD, Assistant Professor, Head of Bioensaios e Dinâmica Celular Lab, Dept. of Chemistry and Biochemistry Biosciences Institute/IBB-UNESP, P.O.Box: 510, ZipCode: 18618-970, Rubião Jr—Botucatu—São Paulo—Brazil.

      E-mail: wzambuzzi@ibb.unesp.br

    Search for more papers by this author

  • Conflict of Interest: The authors declare that there is no conflict of interest.

ABSTRACT

Reactive oxygen species (ROS) modulate a variety of intracellular events, but their role in osteoblast adhesion and spreading remains unclear. ROS is a very-known physiological modulators of Protein Tyrosine Phosphatases activities, mainly to low molecular weight protein tyrosine phosphatase (LMW-PTP) activity. As this biological mechanism is not clear in osteoblast adhesion, we decided to investigate ROS levels and phosphorylations of FAK and Src, identifying these proteins as potential substrates to LMW-PTP activity. Our results showed that during osteoblast adhesion/spreading (30 min and 2 h of seeding) the intracellular ROS content (hydrogen peroxide) is finely regulated by an effective anti-oxidant system [catalase and Superoxide Dismutase (SOD) activities were evaluated]. During the first 30 min of adhesion, there was an increase in ROS production and a concomitant increase in focal adhesion kinase (FAK) activity after its phosphorylation at Tyrosine 397 (Y397). Moreover, after 2 h there was a decrease in ROS content and FAK phosphorylation. There was no significant change in LMW-PTP expression at 30 min or 2 h. In order to validate our hypothesis that LMW-PTP is able to control FAK activity by modulating its phosphorylation status, we decided to overexpress and silence LMW-PTP in this context. Our results showed that FAK phosphorylation at Y397 was increased and decreased in osteoblasts with silenced or overexpressed LMW-PTP, respectively. Together, these data show that ROS modulate FAK phosphorylation by an indirect way, suggesting that a LMW-PTP/FAK supra-molecular complex is involved in transient responses during osteoblast adhesion and spreading. J. Cell. Biochem. 115: 1063–1069, 2014. © 2013 Wiley Periodicals, Inc.

Ancillary