Cholesterol efflux assays. Cholesterol efflux assays were performed using electrospray ionization tandem mass spectrometry (ESI-MS/MS) as described previously [24].
Statistical analysis. Statistical analysis was examined with the independent Student’s t-test, significance of difference was set at p Inauhzin [11]. Since LXR is a major activator of SREBP-1c [15], we asked whether t9,t11-CLA induces SREBP-1c LXR dependent. Therefore we analyzed the activity of the LXR inducible promoter region of SREBP-1c with gene reporter assays ( Fig. 1A). THP-1 cells were transfected with plasmids coding the promoter region from ?422 to ?186 of SREBP-1c. This region harbors two LXR binding sites at ?349/?334 bp and ?298/?283 bp. Treatment with t9,t11-CLA resulted in a significant activation of the reporter gene, whereas CLA treatment of cells transfected with constructs containing mutations in the first, second, or both LXR binding sites, did not affect promoter activity. These results demonstrate that t9,t11-CLA induces the promoter of SREBP-1c by a LXR dependent mechanism.