Phospholipase D Activation by Sphingosine 1-Phosphate Regulates Interleukin-8 Secretion in Human Bronchial Epithelial Cells

• Published in: The Journal of biological chemistry 2002-08, Vol.277 (33), p.30227-30235
• Main Authors: Cummings, Rhett J., Parinandi, Narasimham L., Zaiman, Ari, Wang, Lixin, Usatyuk, Peter V., Garcia, Joe G.N., Natarajan, Viswanathan
• Format: Article
• Language: English
• Subjects: Bronchi - cytology; Bronchi - drug effects; Bronchi - metabolism; Enzyme Activation; Epithelial Cells - drug effects; Epithelial Cells - metabolism; Humans; Interleukin-8 - metabolism; Lysophospholipids; Pertussis Toxin; Phospholipase D - metabolism; Protein Kinase C - metabolism; Signal Transduction - drug effects; Sphingosine - analogs & derivatives; Sphingosine - pharmacology; Virulence Factors, Bordetella - pharmacology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M111078200

Sphingosine 1-phosphate (S1P), a potent bioactive sphingolipid, has been implicated in many critical cellular events, including a regulatory role in the pathogenesis of airway inflammation. We investigated the participation of S1P as an inflammatory mediator by assessing interleukin-8 (IL-8) secretion and phospholipase D (PLD) activation in human bronchial epithelial cells (Beas-2B). S1P1, S1P3, S1P4, S1P5, and weak S1P2 receptors were detected in Beas-2B and primary human bronchial epithelial cells. S1P stimulated a rapid activation of PLD, which was nearly abolished by pertussis toxin (PTX) treatment, consistent with S1P receptor/Gi protein coupling. S1P also markedly induced Beas-2B secretion of IL-8, a powerful neutrophil chemoattractant and activator, in a PTX-sensitive manner. This S1P-mediated response was dependent on transcription as indicated by a strong induction of IL-8 promoter-mediated luciferase activity in transfected Beas-2B cells and a complete inhibition by actinomycin D. Beas-2B exposure to 1-butanol, which converts the PLD-generated phosphatidic acid (PA) to phosphatidylbutanol by a transphosphatidylation reaction, significantly attenuated the S1P-induced IL-8 secretion, indicating the involvement of PLD-derived PA in the signaling pathway. Inhibition of 12-O-tetradecanoyl-phorbol-13-acetate-stimulated IL-8 production by 1-butanol further strengthened this observation. Blocking protein kinase C and Rho kinase also attenuated S1P-induced IL-8 secretion. Our data suggest that PLD-derived PA, protein kinase C, and Rho are important signaling components in S1P-mediated IL-8 secretion by human bronchial epithelial cells.