The Mechanism Of Trans Fatty Acids Induced Inflammation Of Human Umbilical Vein Endothelial Cells

In China, there was a population of 260 million suffered obesity and high blood pressure and there were 300 million people die from cardiovascular disease for one year, especially atherosclerosis.It has been shown that the relationship between TFAs and cardiovascular disease in recent years.TFA are widely used in the food industry derived from partial hydrogenation of vegetables oil.In prospective studies,the intake of trans fatty acids (TFA) that contain at least one carbon-carbon trans double bond leads to atherosclerosis, insulin resistance,obesity,hypertension and type 2 diabetes.This relation can be explained by several mechanisms.One of this is that TFAs promote vascular disease mainly by promoting vascular endothelial cell (EC) inflammation and Endothelial dysfunction.Consumption of TFA above the population range of consumption increase LDL cholesterol and decrease HDL cholestero.TFA consumption is known to influence the plasma biomarkers of inflammation and endothelial dysfunction like increase the soluble intercellular adhesion molecule-1 (SICAM-1), soluble vascular cell adhesion molecule-1 (SVCAM-1) and E-selectin expression.TFA induced endothelial cell apoptosis through Caspase pathway and promote endothelial inflammatory cytokine release, but, whether there exists a specific receptor for TFA to activate the pro-inflammation at the cell membranes is unknow.There is now evidence for the cellular compartmentalization of signaling pathways in the last decade.Lipid rafts which are specialized membrane microdomains, enriched with cholesterol and sphingolipids have been reported be an important sites for the modulation of signaling cascades initiated.Lipid rafts are thought to paly an organizing centers for cell signal transduction, such as inflammation, pro-apoptotic and anti-apoptotic.It has been reported that polyunsaturated fatty acids such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) might change the structure of lipid rafts. DHA could also regulate interleukin-2-signal pathway by changing the lipids component of lipid rafts. So we supposed that the impact of trans fatty acids on the cells may related to the structure and function of lipid rafts.In our study,we use the lipid raft disrupting agent to damage the lipid rafts. Compare the effect of TFAs on cell inflammation before and after when lipid rafts were disrupted by agents to confirm the lipid rafts as the key role in TFAs inducing inflammation.First,we use the real-time PCR to test the expression level of inflammation-related biomarkers such as ICAM-1,VCAM-1 and IL-6 when the HUVEC treated by 9c18:l and 9t18:1.After that,we test the inflammation-related cell signal in HUVEC by western blot,compare the activation of NF-kb and ERK1/2 by 9c 18:1 and 9t18:1 stimulating or not to provide the relation of TFAs and inflamation.At last,we try to find the role of lipid rafts in EC inflammation,compare the effect of 9c18:1 and 9t18:1 on HUVEC inflammation before and after when lipid rafts were disrupted by agents. We use the western blot to test the expression level of inflammatory receptor TLR4 to find the relation of lipid rafts and the receptor protein in EC inflammation.The main research results obtained are as follows:1.TFAs could increase the expression level of inflammatory cytokines. Both 9c 18:1 and 9t18:1 could increase the mRNA expression level of inflammatory cytokines such as ICAM-1, VCAM-1 and IL-6.Only 9t18:1 increase the expression level conspicuous.2.TFAs could activate the cell signal pathyway regulating the EC inflammation.The 9t18:1 could promote the p65 of NF-kb enter into the cell nucleus and increase the phosphorylation level of ERK1/2.This can explain TFAs increase the expression level of inflammatory cytokines by activating the cell signal pathyway regulating the EC inflammation.3.Lipid rafts involved in TFAs induced EC inflammation.Lipid raft disrupting agent (MβCD) at a concentration of lOmM treated on HUVECs for 50 min,the expression of marker proteins (caveolin-1) on lipid rafts decreased significantly. After removal of lipid rafts, inflammation factor expression was significantly reduced,the cell signal pathyway activating was blocked,which indicating that disruption of lipid rafts could inhibit EC inflammation.4.Lipid rafts influence the expression level of inflammatory receptor.The 9t18:1 could increase the expression level of inflammatory receptor TLR4.After removal of lipid rafts, the inflammatory receptor TLR4 expression level was significantly reduced,which indicating that lipid rafts can influence the relation of TFAs and inflammatiory receptor,change the EC inflammation.