The activation of PPARg by ligands, including conjugated linoleic acid (CLA) isomers, plays an important role in the immune response. Among CLA isomers, trans-10, cis-12 (t10c12)-CLA is known to participate in the modulation of pro-inflammatory cytokine secretion. The aim of the present study was to assess the effect of t10c12-CLA on PPARg activation, NF-kB activation and TNF-a expression in lipopolysaccharide (LPS)-naive and LPS-stimulated porcine peripheral blood mononuclear cells (PBMC). In addition, the effect of PPARg inhibition on NF-kB activation and TNF-a expression in porcine PBMC was examined. t10c12-CLA was found to increase TNF-a expression and NF-kB activity in LPS-naive porcine PBMC. In contrast, t10c12-CLA decreased TNF-a expression and NF-kB activity in LPS-stimulated porcine PBMC. t10c12-CLA up-regulated PPARg activity and mRNA expression in both LPS-naive and LPS-stimulated porcine PBMC. GW9662, a PPARg antagonist, completely negated the modulating effects of t10c12-CLA on TNF-a expression and NF-kB activity in both LPS-naive and LPS-stimulated porcine PBMC. These results suggest that t10c12-CLA can modulate TNF-a production and NF-kB activation by a PPARg-dependent pathway in porcine PBMC.

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