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Saturated fatty acids activate TLR‐mediated proinflammatory signaling pathways
Author(s) -
Hwang Daniel,
Huang Shurong,
Rutkowsky Jennifer M.,
Snodgrass Ryan G.,
Ono-Moore Kikumi D.,
Schneider Dina A.,
Newman John W.,
Adams Sean H.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.364.8
Subject(s) - tlr2 , tlr4 , proinflammatory cytokine , chemistry , toll like receptor , docosahexaenoic acid , fatty acid , biochemistry , nf κb , signal transduction , receptor , polyunsaturated fatty acid , innate immune system , inflammation , biology , immunology
Toll‐like receptor 4 (TLR4) and TLR2 were shown to be activated by saturated fatty acids (SFAs) but inhibited by docosahexaenoic acid (DHA). However, one report (ATVB 11:1944, 2009) suggested that SFA‐induced TLR activation in cell culture systems is due to contaminants in BSA used for conjugating fatty acids. This report casted doubt about proinflammatory effects of SFAs. Our studies herein demonstrate that sodium palmitate (C16:0) or laurate (C12:0) without BSA conjugation induced phosphorylation of IκBα, JNK, ERK, and NFκB p65 and TLR target gene expression in THP1 monocytes or RAW264.7 macrophages, respectively when cultured in low FBS (0.25%) medium. C12:0 induced NFκB activation through TLR2 dimerized with TLR1 or TLR6, and through TLR4. Since BSA was not used in these experiments, contaminants in BSA have no relevance. Unlike suspension cells (THP‐1), BSA conjugation is required for C16:0 to induce TLR target gene expression in adherent cells (RAW264.7). BSA‐conjugated C16:0 transactivated TLR2 dimerized with TLR1 or TLR6, and through TLR4 as seen with C12:0. These results and additional studies with LPS sequester polymixin B and MyD88−/− macrophages indicated that SFA‐induced activation of TLR2 or TLR4 is a fatty acid‐specific effect, but not due to contaminants in BSA or fatty acid preparations. (USDA‐ARS‐WHNRC Program Funds and NIHDK 064007)