p38 MAP kinase regulates IL-1 beta responses in cultured airway smooth muscle cells

J D Laporte1, P E Moore, T Lahiri

  • 1Physiology Program, Harvard School of Public Health, Boston, Massachusetts 02115, USA.

Insights

Interleukin-1 beta triggers airway smooth muscle hyporesponsiveness by increasing COX-2 via p38 MAP kinase. Inhibiting p38 MAP kinase blocks this effect, suggesting a key role in airway inflammation.

Area of Science:

  • Cellular and Molecular Biology
  • Immunology
  • Respiratory Medicine

Background:

  • Interleukin (IL)-1 beta is known to induce cyclooxygenase (COX)-2 expression in human airway smooth muscle (HASM) cells, leading to beta-adrenergic hyporesponsiveness.
  • The precise signaling pathways mediating these effects require further elucidation.

Purpose of the Study:

  • To investigate the role of p38 mitogen-activated protein (MAP) kinase in IL-1 beta-induced COX-2 expression and beta-adrenergic hyporesponsiveness in HASM cells.

Main Methods:

  • HASM cells were treated with IL-1 beta and/or p38 MAP kinase inhibitor (SB-203580).
  • COX-2 expression, prostaglandin E(2) (PGE(2)) release, and nuclear factor binding (AP-1, NF-kappa B) were measured.
  • Beta-adrenergic hyporesponsiveness was assessed by measuring HASM stiffness using magnetic twisting cytometry.

Main Results:

  • IL-1 beta significantly increased p38 MAP kinase phosphorylation and COX-2 expression.
  • The p38 inhibitor SB-203580 markedly reduced IL-1 beta-induced COX-2 expression and PGE(2) release.
  • SB-203580 abolished the IL-1 beta-mediated hyporesponsiveness of HASM cells to isoproterenol.
  • p38 MAP kinase activation was not dependent on AP-1 or NF-kappa B, and NF-kappa B was not required for IL-1 beta-induced COX-2 expression.

Conclusions:

  • p38 MAP kinase is a critical component of the signaling pathway through which IL-1 beta induces COX-2 expression, PGE(2) release, and beta-adrenergic hyporesponsiveness in HASM cells.
  • Targeting the p38 MAP kinase pathway may offer a therapeutic strategy for inflammatory airway diseases characterized by beta-adrenergic hyporesponsiveness.

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