Involvement of phospholipases D1 and D2 in sphingosine 1-phosphate-induced ERK (extracellular-signal-regulated kinase) activation and interleukin-8 secretion in human bronchial epithelial cells

Abstract

Sphingosine 1-phosphate (S1P), a metabolite of sphingomyelin degradation, stimulates interleukin-8 (IL-8) secretion in human bronchial epithelial (Beas-2B) cells. The molecular mechanisms regulating S1P-mediated IL-8 secretion are yet to be completely defined. Here we provide evidence that activation of phospholipases D1 and D2 (PLD1 and PLD2) by S1P regulates the phosphorylation of extracellular-signal-regulated kinase (ERK) and IL-8 secretion in Beas-2B cells. S1P, in a time- and dose-dependent manner, enhanced the threonine/tyrosine phosphorylation of ERK. The inhibition of S1P-induced ERK phosphorylation by pertussis toxin and PD 98059 indicated coupling of S1P receptors to G(i) and the ERK signalling cascade respectively. Treatment of Beas-2B cells with butan-1-ol, but not butan-3-ol, abrogated the S1P-induced phosphorylation of Raf-1 and ERK, suggesting that PLD is involved in this activation. The roles of PLD1 and PLD2 in ERK activation and IL-8 secretion activated by S1P were investigated by infecting cells with adenoviral constructs of wild-type and catalytically inactive mutants of PLD1 and PLD2. Infection of Beas-2B cells with the wild-type constructs resulted in the activation of PLD1 and PLD2 by S1P and PMA. Also, the enhanced production of [(32)P]phosphatidic acid and [(32)P]phosphatidylbutanol in the presence of butan-1-ol and the increased phosphorylation of ERK by S1P were blocked by the catalytically inactive mutants hPLD1-K898R and mPLD2-K758R. Transient transfection of Beas-2B cells with human PLD1 and mouse PLD2 cDNAs potentiated S1P-mediated IL-8 secretion compared with vector controls. In addition, PD 98059 attenuated IL-8 secretion induced by S1P in a dose-dependent fashion. These results demonstrate that both PLD1 and PLD2 participate in S1P stimulation of ERK phosphorylation and IL-8 secretion in bronchial epithelial cells.

Interleukin-17A activation on bronchial epithelium and basophils: a novel inflammatory mechanism

“…BEAS-2B cells maintain the characteristics of primary bronchial epithelial cells including expression of ICAM-1, eotaxin and CXCL8 [19][20][21], while KU812 cells constitute the phenotypes of basophils, such as histamine release and FcgammaRII expression [22]. We also used primary bronchial epithelial cells and peripheral blood basophils to confirm our findings of BEAS-2B and KU812 cells.…”

Expression Profiles of the Mouse Lung Identify a Molecular Signature of Time-to-Birth

“…Npr3 (natriuretic peptide receptor-3) has previously been shown to be rapidly down-regulated after birth and is proposed to maintain the fetal lung in a fluid-filled state (32). Pld1 is a phosphatidylcholine-specific phospholipase expressed in the lung (33,34) that may be involved in surfactant metabolism.…”

“…In dataset L1, the time points can be represented as the vector (E14, E17, E19, P7, P14, P28), which is correlated with (0, 3,5,12,19,33). The time-to-birth profile is Abs((0, 3, 5, 12, 19, 33) -5.5) 5 (5.5, 2.5, 0.5, 6.5, 13.5, 27.5).…”

Involvement of Phospholipase D2 in Lysophosphatidate-induced Transactivation of Platelet-derived Growth Factor Receptor-β in Human Bronchial Epithelial Cells

“…HBEpCs-Previous studies have demonstrated stimulation of mitogenic signaling pathways for S1P, LPA, and growth factors in human airway smooth muscle and epithelial cells (1,21,34,35). To examine ERK activation further, HBEpCs were challenged with 1 M LPA or 20 ng/ml PDGF-BB, and phosphorylation of ERK was analyzed by Western blotting with phospho-specific antibodies against threonine/ tyrosine residues.…”