The Role Of PLA₂/LPC Pathway In The Mechanism Of Hepatocytic Lipoapoptosis

ObjectiveTo investigate the role of PLA2/LPC pathway in FFAs-induced hepatocyte lipoapoptosis and its further molecular mechanismMethodsChang cells were incubated with different concentration of Palmitic acid (PA) together with or without PLA2 inhibitors for 18hs. Cell viability was assessed using the MTT assay. Cell apoptosis was determined by Hoechst33258 staining using fluorescence microscopy and AnnexinV-PI staining by flow cytometry. Intracellular lipids were measured by Nile red using digital fluorescent microscopy. PLA2 expression was determined by Western blot and Q-PCR. Intracellular LPC content was measured by an enzymatic assay.ResultThe exposure of Chang cells to PA induced decreased cell viability and classical apoptosis in dose-dependent manner; and Chang cells treated with PA showed significant activation of PLA2, high levels of intracellular LPC content. Pretreatment Chang cells with BEL, a specific inhibitor for iPLA2, AACOCF3, a specific inhibitor for cPLA2 or sPLA2-â…¡A Inhibitor I, an inhibitor for sPLA2 protected Chang cells' viability and significantly decreased PA-mediated lipoapoptosis(P<0.05).And pretreatment Chang cells with BEL or sPLA2-â…¡A Inhibitor I decrease intracellular LPC content, while AACOCF3 had no apparent effect on intracellular LPC content in PA-induced Chang cells, suggesting that the role of iPLA2 and sPLA2 is more important than cPLA2 in PA-induced LPC increase.ConclusionThese results showed that role of Phosphatidolipase A2/lysophosphatidylcholine (PLA2/LPC) pathway appears to be an important event in the mechanism of PA-induced hepatocyte lipoapoptosis.