Proteomics for the discovery of nuclear bile acid receptor FXR targets.
Bottom Line: To examine if the differences found in the proteomics assay reflected differences at the mRNA level, a microarray assay was generated on hepatic samples from wild type and FXR(-/-) mice treated with a FXR ligand and compared to vehicle treatment.At least six proteins were shown to be regulated only at a post-transcriptional level.This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease.
Affiliation: Department of Translational Pharmacology, Consorzio Mario Negri Sud, Santa Maria Imbaro (CH), 66030, Italy. email@example.comShow MeSH
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Mentions: In a 2D-DIGE assay, comparing hepatic protein samples from INT-747 with vehicle treated mice, 19 spots were more than two-fold different in protein levels (Fig. 1A, Tables S1 and S2). For seven spots the amount of protein was higher in the INT-747 samples compared to vehicle, while in the rest it was reduced by the FXR ligand treatment. The proteins in the spots were identified by MALDI-TOF MS (Table 1). In spot 8302 two different proteins were found, argininosuccinate synthase and 3-ketoacylCoA thiolase. It is therefore unclear which protein, or if possibly both were down regulated in response to the FXR activation. In this study we also compared hepatic samples from FXR−/− mice, treated with the semi-synthetic bile acid INT-747 or vehicle, and no differences in protein amounts could be detected for any of the proteins in Table 1 (data not shown). This comparison was made as an objective control for non-FXR mediated effects that could relate to the weak agonistic effect of INT-747 on the membrane TGR5 receptor .
Affiliation: Department of Translational Pharmacology, Consorzio Mario Negri Sud, Santa Maria Imbaro (CH), 66030, Italy. firstname.lastname@example.org