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RhoA inhibition activates MMP‐2 via a PI3K dependent mechanism.
Author(s) -
Ispanovic Eric,
Haas Tara L
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a193-a
Subject(s) - rhoa , stress fiber , matrix metalloproteinase , chemistry , microbiology and biotechnology , pi3k/akt/mtor pathway , actin , rho kinase inhibitor , biophysics , cell , cytoskeleton , signal transduction , biochemistry , rho associated protein kinase , biology
Basement membrane and interstitial matrix proteolysis are critical early steps in the angiogenic process, and require matrix metalloproteinase (MMP) activation. Skeletal muscle endothelial cells cultured as a monolayer on type I collagen exhibit high levels of stress fibre polymerization and low levels of MMP activity, indicative of a quiescent state. Depolymerization of stress fibres by RhoA inhibition with 10 μM H1152, an inhibitor of Rho kinase, increased cortical actin and MMP‐2 activation. We investigated the effect of RhoA inhibition on the localization of membrane type‐1 (MT1)‐MMP, the activator of MMP‐2, and found that H1152 treatment increased cell surface MT1‐MMP and caused MT1‐MMP localization to areas of strong cortical actin staining. Cortical actin polymerization is hypothesized to involve PI3K and we found that phospho‐AKT levels increased as early as 30 min post H1152 exposure and remained elevated for more than 2 hrs. Pretreatment with 10 μM LY294009, an inhibitor of PI3K, abolished the increase in active MMP‐2 observed with H1152 treatment alone. These results indicate that inhibition of RhoA, through a PI3K dependent mechanism, increases cell surface MT1‐MMP and localizes it to areas of cortical actin polymerization, which facilitates activation of MMP‐2. Funded by NSERC.