GHB Dependent Changes in PEA-15 Gene Expression in Different Human Cell Lines

Abstract

Background. Gamma-hydroxybutyric acid (GHB) is found to be present endogenously in mammalian brains. It has been abused increasingly in recent years, particularly in date rape sexual assaults. Metabolism of GHB happens very rapidly; it disappears within 12 hours, making its detection in criminal cases very complicated. Aim. This study intended to determine whether PEA-15 gene expression in human cell lines can be used as a marker for expanding the window of GHB detection beyond 12 hours. Methods. The effects of GHB on cell viability was determined by use of the MTT assay. Quantitative real-time PCR and western blots were used to assess the effect of GHB exposure on PEA-15 mRNA and protein levels respectively in human brain and blood cells. Results. The viability of human brain cells was decreased as GHB concentrations increased. PEA-15 mRNA levels increased in 1321N1 and SH-SY5Y cells by 4.2- and 3.7-fold respectively, after a 100 µM GHB treatment (p<0.01 both), but with no change at 1µM GHB. However, PEA-15 mRNA levels were increased significantly in THP-1 cells by 40.8-fold after a 10 µM GHB treatment (p<0.01), but with no change at 900 µM GHB. PEA-15 protein expression levels were increased in THP-1 cells by 1.9- and 1.6-fold (p<0.001) after 10µM and 900µM GHB treatments respectively, and increased in SH-SY5Y cells by 1.6-fold (p<0.05) after a 100 µM GHB treatment. However, there were no changes in PEA-15 protein levels in SH-SY5Y cells after 24 hours of GHB exposure. Conclusion. The results of this study on human cell lines support the previous study in mice, which suggests PEA-15 levels as a possible surrogate marker for GHB administration beyond 12 hours. Additional studies are required. Keywords. GHB, PEA-15, SH-SY5Y cells, SH-SY5Y cells, and THP-1 cells.