Mitogen-Activated Protein Kinase Modulation of Nuclear Factor-κB–Induced Granulocyte Macrophage–Colony-Stimulating Factor Release from Human Alveolar Macrophages

Abstract

Granulocyte macrophage–colony-stimulating factor (GM-CSF), released from alveolar macrophages (AM), is an important regulator of eosinophil, T cell, and macrophage function and survival. We determined the mechanisms of GM-CSF regulation in AM from normal volunteers activated by lipopolysaccharide (LPS) by examining the role of nuclear factor-κB (NF-κB), and of p38 mitogen-activated protein (MAP) kinase and MAP kinase kinase (MKK-1). PD 098059 (10 μM), an inhibitor of upstream activator of MKK-1, inhibited GM-CSF expression, but the expression of GM-CSF was not inhibited by SB 203580 (10 μM), an inhibitor of p38-MAP kinase. Phosphorylation of extracellular signal–regulated kinase-1 (ERK-1), ERK-2, and p38 MAP kinase by LPS were demonstrated on Western blot analysis. LPS increased NF-κB:DNA binding as examined by electrophoretic mobility shift assay, but this was not suppressed by PD 098059 or by SB 203580. LPS induced an increase in NF-κB activation as examined by p50 translocation assay without suppressio...