Leukemia inhibitory factor induces the 85-kDa cytosolic phospholipase A(2) gene expression in cultured human bronchial epithelial cells

Leukemia inhibitory factor (LIF) has become increasingly recognized as an important regulator of inflammation. This study is designed to determine whether LIF has an effect on arachidonate metabolism in human airway epithelial cells. LIF (100 ng/ml) induced a significantly increased release of prelabeled [H-3] arachidonic acid (AA) from the human bronchial epithelial cell line (BEAS 2B cell) as well as from the primary cultures of human bronchial epithelial cells. Exposure of the LIF stimulated BEAS 2B cells to calcium ionophore A23187 (10(-5) M, 15 min) caused a further increase of [3H]AA release. To identify the role of cytosolic phospholipase A(2) (cPLA(2)) in this upregulation of AA release, further experiments were performed to determine the expression of cPLA(2) in the BEAS 2B cells. Immunoblot analysis indicated that LIF increased cPLA(2) protein expression. Ribonuclease protection assay showed that LIF induced an increase of cPLA(2) mRNA levels following 3 h to 24 h treatment. Nuclear run-on experiments suggested that LIF upregulated cPLA, gene expression through post-translational regulation. These results demonstrate that LIF induces cPLA(2) gene expression and modulates arachidonate metabolism in airway epithelial cells.