Induction of cytosolic phospholipase A2 by lipopolysaccharide in canine tracheal smooth muscle cells: Involvement of MAPKs and NF-κB pathways

Shue Fen Luo*, Wei Ning Lin, Chuen Mao Yang, Chiang Wen Lee, Chang Hui Liao, Yann Lii Leu, Li Der Hsiao

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

36 Scopus citations

Abstract

Cytosolic phospholipase A2 (cPLA2) plays a pivotal role in mediating agonist-induced arachidonic acid (AA) release for prostaglandins (PG) synthesis induced by bacterial lipopolysaccharide (LPS) and cytokines. However, the intracellular signaling pathways mediating LPS-induced cPLA2 expression and PGE2 synthesis in canine tracheal smooth muscle cells (TSMCs) remains unknown. LPS-induced expression of cPLA2 and release of PGE2 was attenuated by inhibitors of tyrosine kinase (genistein), phosphatidylcholine-phospholipase C (D609), phosphatidylinositol-phospholipase C (U73122), PKC (GF109203X and staurosporine), removal of Ca2+ by BAPTA/AM plus EDTA, MEK1/2 (PD98059), p38 (SB202190), JNK (SP600125), and phosphatidylinositol 3-kinase (PI3-K; LY294002 and wortmannin). The involvement of MPAKs in LPS-induced responses was further confirmed by transfection of TSMCs with dominant negative mutants of ERK2 and p38. LPS-induced cPLA2 expression and PGE2 synthesis was inhibited by a selective NF-κB inhibitor (helenalin) and transfection with dominant negative mutants of NF-κB inducing kinase (NIK), IκB kinase (IKK)-α, and IKK-β, consistent with that LPS-stimulated both IκB-α degradation and NF-κB translocation into nucleus in these cells. LPS-stimulated cPLA2 phosphorylation was inhibited by PD98059, GF109203X, and staurosporine, indicating the regulation by p42/p44 MAPK and PKC. Moreover, LPS-induced up-regulation of cPLA2 and COX-2 linked to PGE2 synthesis was inhibited by AACOCF3 (a selective cPLA2 inhibitor), implying the involvement of cPLA2 in these responses. These findings suggest that phosphorylation and expression of cPLA2 correlates with the release of PGE2 from LPS-challenged TSMCs, at least in part, mediated through MAPKs and NF-κB signaling pathways. LPS-mediated responses were modulated by PLC, Ca2+, PKC, tyrosine kinase, and PI3-K in TSMCs.

Original languageEnglish
Pages (from-to)1201-1211
Number of pages11
JournalCellular Signalling
Volume18
Issue number8
DOIs
StatePublished - 08 2006

Keywords

  • Ca
  • Cyclooxygenase
  • Cytosolic phospholipase A
  • MAPKs
  • Phospholipase C
  • Prostagladins
  • Protein kinase C

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