Specific phospholipid oxidation products inhibit ligand activation of toll-like receptors 4 and 2.

Published

Journal Article

OBJECTIVE: We have previously shown that phospholipid oxidation products of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (ox-PAPC) inhibit lipopolysaccharide (LPS)-induced E-selectin expression and neutrophil binding in human aortic endothelial cells (HAECs). The current studies identify specific phospholipids that inhibit chemokine induction by Toll-like receptor-4 (TLR4) and -2 (TLR2) ligands inECs and macrophages. METHODS AND RESULTS: Measurements of interleukin (IL)-8 and monocyte chemotactic protein-1 levels secreted from ox-PAPC- and LPS-cotreated ECs indicate that ox-PAPC inhibits activation of TLR4 by LPS. The effects of IL-1beta and tumor necrosis factor-alpha, which utilize the same intracellular signaling molecules, were not inhibited. Cell fractionation and immunofluorescence analyses demonstrate that LPS induces membrane translocation of the LPS receptor complex to a lipid raft/caveolar fraction in ECs. Ox-PAPC inhibits this translocation and alters caveolin-1 distribution. Supporting an important role for caveolae in LPS action, overexpression of caveolin-1 enhanced LPS-induced IL-8 synthesis. Ox-PAPC also inhibits the effect of TLR2 and TLR4 ligands in human macrophages. CONCLUSIONS: These studies report a novel mechanism that involves alterations to lipid raft/caveolar processing, by which specific phospholipid oxidation products inhibit activation by TLR4 and TLR2 ligands. These studies have broader implications for the role of ox-PAPC as a regulator of specific lipid raft/caveolar function.

Full Text

Cited Authors

  • Walton, KA; Cole, AL; Yeh, M; Subbanagounder, G; Krutzik, SR; Modlin, RL; Lucas, RM; Nakai, J; Smart, EJ; Vora, DK; Berliner, JA

Published Date

  • July 2003

Published In

Volume / Issue

  • 23 / 7

Start / End Page

  • 1197 - 1203

PubMed ID

  • 12775576

Pubmed Central ID

  • 12775576

Electronic International Standard Serial Number (EISSN)

  • 1524-4636

International Standard Serial Number (ISSN)

  • 1079-5642

Digital Object Identifier (DOI)

  • 10.1161/01.atv.0000079340.80744.b8

Language

  • eng