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

Gustavo V. O. Fernandes, Alexandre D. M. Cavagis, Carmen V. Ferreira, Beni Olej, Mauricio de Souza Leao, Claudia L. Yano, Maikel Peppelenbosch, Jose Mauro Granjeiro, Willian F. Zambuzzi*

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    29 Citations (Scopus)

    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 (30min and 2h 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 30min 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 (Y-397). Moreover, after 2h there was a decrease in ROS content and FAK phosphorylation. There was no significant change in LMW-PTP expression at 30min or 2h. 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 Y-397 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. (c) 2013 Wiley Periodicals, Inc.

    Original languageEnglish
    Pages (from-to)1063-1069
    Number of pages7
    JournalJournal of Cellular Biochemistry
    Volume115
    Issue number6
    DOIs
    Publication statusPublished - Jun-2014

    Keywords

    • ADHESION
    • FAK
    • LMW-PTP
    • OSTEOBLAST
    • REDOX
    • ROS
    • PROTEIN-TYROSINE-PHOSPHATASE
    • CELL-ADHESION
    • DIFFERENTIATION
    • OXIDATION
    • SURFACE
    • BONE

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