Effect of pistachio oil on gene expression of IFN-induced protein with tetratricopeptide repeats 2: a biomarker of inflammatory response.

When incorporated into the diet, pistachios have a beneficial effect on lipid and lipoprotein profiles. However, little is known about potential anti-inflammatory properties. This study was conducted to determine whether pistachio oil and an organic extract from pistachio oil extract (PE) regulated expression of inflammation-related genes. A mouse macrophage cell line (RAW 264.7 cells) was treated with pistachio oil and gene expression microarray analyses were performed. Pistachio oil significantly affected genes involved in immune response, defense response to bacteria, and gene silencing, of which INF-induced protein with tetratricopeptide repeats 2 (Ifit-2) was the most dramatically reduced. PE reduced the LPS-induced Ifit-2 by 78% and the bioactive molecules contained in PE, linoleic acid, and beta-sitosterol recapitulated this inhibition. Promoter analysis identified two adjacent IFN-stimulated response elements, which lie between -110 and -85bp of the 5'-flanking region of the Ifit-2 promoter, as being responsive to LPS activation and inhibition by PE. Our results indicate that pistachio oil and bioactive molecules present therein decrease Ifit-2 expressions, and due to the sensitivity of this effect, this gene is a potential biomarker for monitoring diet-induced changes in inflammation.