Effects Of Fatty Acids And Peroxisome Proliferator-Activated Receptors(PPARs) On Plasminogen Activator Inhibitor-1(PAI-1) Expression In Human Endothelial Cells And Mechanism Exploring

Atherosclerosis is a multicellular process including changing of function and morphology in the cells in vascular wall, and is associates with many metabolic and nutritional factors in vivo Elevated levels of plasma plasminogen activator inhibitor type-i (PM-i) activity is a risk factor for atherosclerotic thrombosis, and is associated with the levels of plasma triglyceride and its metabolic production in vivo Peroxisome prohferator activated receptors (PPARs) are a family of three transcriptional factors, PPAR a , P I 6 and ?,which can be activated by some metabolic and nutritional factors including fatty acids and drugs mediating the balance of metabolism, then link them with changes in cellular function Endothehal cells (ECs) are a major source of plasma PM-i activity and play an important role in maintaimng the balance of fibnnolysis in vessel wall In the present study we demonstrated the expression of all three types of PPARs in cultured human umbilical vein endothelial cells (HUVECs) by reverse transcription polymerase chain reaction (RT-PCR) And using the same method we determined the effects of unsaturated fatty acids and prostaglandin J2 (PGJ2) which were PPARs activators and saturated fatty acid which could not activates PPARs on the expression of PPARs in ECs by incubating HUVECs with them at a range of concentrations that could activate PPAIRs Tthe results showed that unsaturated fatty acids and PGJ2 as well as saturated fatty acids had no effects on the expression of PPARs in ECs and the direct modulation of PPARs activators to PPARs expression was not found in ECs of the present study Then we demonstrated the effects of unsaturated fatty acids, PGJ2 and saturated fatty acid on the expression of PM-i in ECs, through measuring PM-i expressed by HUVECs after incubation with physiological as well as activating concentrations of unsaturated fatty acids, PGJ2 and saturated fatty acid in levels of mRNA and protein by RT-PCR and enzyme linked immunosorbent assay (ELISA) The unsaturated fatty acids and i5d-PGJ2 induced the expression of PM-i in a dose dependent manner in 4 ECs, but saturated fatty acids had no inducing effect In order to explore the mechamsm of the induction of unsaturated fatty acids?on PM-I expression in ECs, to test the hypotheses that PM-i gene is a target gene of PPARs in human ECs and the unsaturated fatty acids act through activating PPARs expressed in ECs to enhance transcription of PM-i gene, and then induce to the secretion of PM-i, we constructed a PM-i promoter controlling reporter gene vector, transfected ECs line-ECV3O4 with this vector and tested the reporter抯 expression to demonstrate the transcnptional level of PM-i gene in ECs The transfected ECV3O4 were stimulated by an effective, inducing concentration of unsaturated fatty acids and saturated fatty acid. The results showed that unsaturated acids could increase the transcription of PM-i gene in ECs Then we cotransfected ECV3O4 with various amounts of expression plasmids for PPAR a and PPAR i, and found the activation of PM-i transcription by PPAR a in ECs, but not by PPAR v Finally we also treated ECV3O4 cotransfected with certain effective amount of expression plasmids for PPAR a or the same amount of expression plasmids for PPAR 憕 with fatty acids in concentration mentioned above, the results showed that PPAR a cooperated with unsaturated fatty acids in enhancing the transcription of PAl-i gene, but PPAR y di...