Studies Of Molecular Mechanism Of Gemfibrozil On Regulation Of Cellular Lipid Metabolism

Cholesterol is blanket of neutral fat(triglycerides and cholesterol) and lipids(phospholipids, lipids, sterols, steroids) in plasma. And it is essential substances of basal metabolism in living cells. Due to improper diet or lack of exercise, more and more obese patients are appearance, which caused hyperlipidemia increasingly widespread attention.Commonly used lipid-lowering drugs include Bile acid sequestrant resin, statins, Nicotinic Acids and benzene oxygen acid derivatives. Among them, gemfibrozil is a relatively new lipid regulating agent which belongs to phenoxy aromatic acids. Its mechanism is mainly inhibition of very low density lipoprotein(VLDL) in the liver synthesis, increasing lipoprotein lipase activity, promoting catabolism of VLDL, thereby reducing the formation of TG and LDL. Because we only know gemfibrozil mechanism between the organizations, but its lipid regulation mechanisms within the cell remains to be seen. In order to clarify the mechanism of gemfibrozil to reduce drug side effects, we were discussed gemfibrozil intracellular mechanism of action of lipids by saccharomyces cerevisiae as a model.In order to explore the mechanism of gemfibrozil in cells, first we found that the number of lipid droplets and content of TAG in gemfibrozil-treated wild-type yeast cells by4741 were significant changes, confirmed that gemfibrozil still has a regulatory role for TAG in the cell. Then we choose gene deficient strains which regulating intracellular lipid metabolism, pah1△, tgl3△, tgl4△, tgl3△tgl4△, lro1△, are1△, are2△, dga1△, dgk1△, and observed the change of number of lipid droplets and content of TAG after treatment with gemfibrozil. Since then the content of TAG and number of lipid droplets in cells did not show significant changes when DGK1 knockout, so we initially identified gemfibrozil regulate the metabolism of TAG by gene dgk1 in yeast cells.And then we found that diacylglycerol kinase activity can be suppressed by measuring content of yeast PA after treatment with gemfibrozil. Study for TUP1 and CYC8 gene expression change in cells after treatment with gemfibrozil shows that Gemfibrozil can upregulate gene expression of CYC8 and TUP1, so that the two transcription factors which play a transcriptional inhibition enhanced inhibition of DGK1 gene promoter,thereby inhibited DGK1 gene expression, and thus increase the level of intracellular TAG. In addition, we further explore the sites of action of gemfibrozil on TUP1p-CYC8 p and DGK1 promoter binding. Then we screen gene on tolerated gemfibrozil under pah1△background essential yeast gene overexpression library. Most of them are closely related protein transcription and translation. Therefore we got a foundation for deep understanding of TUP1 and CYC8 at gemfibrozil mechanism in the cell.Although we have been informed mechanism of gemfibrozil action to DGK1 gene, but how gemfibrozil is upregulation of transcription factor TUP1, CYC8 expression, its mechanism remains unclear and pending further inquiry. And we only research gemfibrozil intracellular mechanism of action of lipids. The reason of gemfibrozil reducing the level of the TAG in organizations but improving the content of the TAG in yeast cells also need our further exploration.