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Regulation of matrix metalloproteinase‐1, ‐3, and ‐9 in Mycobacterium tuberculosis‐dependent respiratory networks by the rapamycin‐sensitive PI3K/p70 S6K cascade
Author(s) -
Singh Shivani,
Saraiva Luisa,
Elkington Paul T. G.,
Friedland Jon S.
Publication year - 2014
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/fj.13-235507
Subject(s) - p70 s6 kinase 1 , pi3k/akt/mtor pathway , protein kinase b , matrix metalloproteinase , p110α , chemistry , phosphorylation , biology , signal transduction , cancer research , microbiology and biotechnology , biochemistry
This study was designed to investigate the role of the phosphatidyl inositol 3‐kinase (PI3K)/AKT/p70 S6K signaling path on regulation of primary normal human bronchial epithelial cell‐derived matrix metalloproteinase (MMP)‐1, ‐3, and ‐9 expression in tuberculosis (TB). These MMPs are key in pathological extracellular matrix degradation in TB. Normal human bronchial epithelials were stimulated with conditioned medium from monocytes infected with virulent TB (CoMTb) and components of the PI3K/AKT signaling pathway blocked using specific chemical inhibitors and siRNA. MMP gene expression was measured by RT‐PCR and secretion by ELISA, luminex, or zymography. Phospho‐p70 S6Kwas detected by Western blot analysis and activity blocked by rapamycin. Chemical blockade of the proximal catalytic PI3Kp110 subunit augmented MMP‐1 and MMP‐9 in a dose‐dependent manner (all P <0.001) but suppressed MMP‐3 ( P <0.01). Targeted siRNA studies identified the p110α isoform as key causing 5‐fold increase in TB network‐dependent MMP‐1 secretion to 4900 ± 1100 pg/ml. Specific inhibition of the AKT node suppressed all 3 MMPs. Phospho‐p70 S6K was identified in the cellular model, and rapamycin, a p70 S6K inhibitor, inhibited MMP‐1 ( P <0.001) and MMP‐3 ( P <0.01) but not MMP‐9. Controls were epithelial cells that were unstimulated or exposed to conditioned medium from monocytes not exposed to TB. In summary, blockade of the proximal PI3K catalytic subunit increases MMP‐1 and MMP‐9, whereas rapamycin decreased both MMP‐1 and MMP‐3. The regulation of the PI3K path in TB is complex, MMP specific, and a potential immunotherapeutic target in diseases characterized by tissue destruction.—Singh, S., Saraiva, L., Elkington, P. T. G., Friedland, J. S. Regulation of matrix metalloproteinase‐1, ‐3, and ‐9 in Mycobacterium tuberculosis dependent respiratory networks by the rapamycin‐sensitive PI 3‐kinase/p70 S6K cascade. FASEB J . 28, 85–93 (2014). www.fasebj.org