İnsan Serum Bütirilkolinesterazının Karaciğer Hepg2 Hücrelerinde Lipid Metabolizması ile Etkileşiminin İncelenmesi.

Abstract

Butyrylcholinesterase (BChE) synthesized in liver is mostly associated with the detoxification of xenobiotics. Recently we have shown that in sedentary young males, application of exercise and/or conjugated linoleic acid (CLA) changes both free fatty acids(FFA) and BChE levels. In this study to analyze the involvement of BChE in lipid metabolism, we have applied linoleic acid (LA) and α-linolenic acid (ALA) to HepG2 cells to observe the effects of these lipids on BChE expression. Our experimental group consisted of normal HepG2 cells, in which we analyzed the expression of BChE and the effects of these treatments on cell cycle. HepG2 cells did not display any BChE expression as analyzed by Reverse transcriptase PCR (RT-PCR). Hence wild type human BChE plasmid was amplified and transfected to HepG2 cells. Application of high concentrations of linoleic (500 μM) (LA) and linolenic acid (50 μM) (ALA) to HepG2 cells without BChE transfection caused toxicity as analyzed by flow cytometry. LA was observed to be more toxic than ALA, leading to unattached cells. The IC50 value of LA was found as 149.3 μM and the appropriate LA and ALA concentrations were determined as 5 μM by WST-1 assay. Transfection of BChE plasmid to HepG2 cells yielded increased BChE expression as observed by RT-PCR and activity assays. Application of 5 μM ALA after BChE transfection to HepG2 cells resulted in increased expression of BChE as opposed to both untransfected and transfected cells. The toxicity observed during LA treatment was diminished and cell proliferation increased, although the cells retained a ghost cell like property. Application of ALA on the other led to an overall increase in both cell numbers and BChE expression and activity. Our results indicate that BChE transfections help HepG2 cells to internalize more lipids and lead the cells to a more proliferative state. Hence, the interaction of butyrylcholinesterase with lipid metabolism is much closer than realized before.