Effects Of Epigallocatechin Gallate On M Rna Expression Of Dipeptide Peptidase-4 And Key Enzymes For Lipid Metabolism In Hepatocytes

Objective: This article mainly investigated whether Epigallocatechin gallate(EGCG)in green tea improves triglyceride accumulation in hepatocytes by regulating the expression of dipeptidyl-peptidase 4(DPP4)and m RNA,a key enzyme for lipid metabolism.Methods:(1)Screening cell models that knock out the DPP4 gene in the Gene Expression Omnibus(GEO),enriching the function of differentially expressed genes through the DAVID website,and then comparing the gene content with the Kyoto Encyclopedia of Genes and Genomes(KEGG)database.To examine which pathways and related functions may be encoded in the genome,significant changes occur after DPP4 is knocked out.(2)The Hep G2 cell line of human liver cancer was cultured,and the NAFLD cell model was induced by oleic acid,and then the intervention was performed with EGCG,three groups was divided: control group(NC),FFA group(FFA),both FFA and EGCG group(FFA+EGCG).After 72 h of intervention,the triglyceride content in the cells was determined by triglyceride kit,real-time fluorescence polymerase chain reaction(Real-Time PCR)was used to measure the m RNA expression level in each target gene of each group,the protein translation level of the target gene of each group was measured by the western blot test,and each group of experiments was repeated at least three times in different batches of cells on different days,and the results were included in the parallel statistical analysis of Graph Pad Prism9 graphing.Results:(1)By enriching differentially expressed genes and comparing gene content with the KEGG database,a total of 77 significantly altered biological pathways were screened.Three of these pathways are associated with lipid metabolism,and two of them are in the top ten for significant changes.(2)By detecting the triglyceride content of each group,the results showed that the triglyceride content in the FFA group was significantly higher than that in the NC group(P<0.01),and the triglyceride content in the FFA group after EGCG treatment was significantly lower than that in the FFA group(P<0.05).(3)By detecting the expression level of DPP4 m RNA in cells in each group,the statistics showed that compared with the NC group,the expression level of DPP4 m RNA in the FFA group increased significantly,and the m RNA expression level of DPP4 in the EGCG group decreased significantly,and the difference was statistically significant(P<0.05).(4)By detecting the expression of m RNA,a key enzyme for lipid metabolism in each group of Hep G2 cells,it was found that: the key enzyme involved in fatty acid transport,fatty acid translocase CD36(CD36),fatty acid transporter 2(fatty acid transporter),member 2,SLC27A2/ FATP2)m RNA was not significantly different(ns)in the FFA group compared with the NC group,and there was no significant difference(ns)in the EGCG+FFA group compared with the FFA group.The m RNA of acetyl-Co A carboxylα ase α(ACACA,ACC),a key enzyme involved in lipid synthesis,had no significant difference(ns)in the FFA group compared with the NC group,and there was no significant difference in the expression of EGCG+FFA group compared with the FFA group(ns).The m RNA involved in lipid β oxid α ation peroxisome proliferatorsactivated receptors-α(PPARα)was not significantly different in the FFA group compared with the NC group(ns),and the expression of EGCG+FFA was significantly increased compared with the FFA group(P<0.05).Carnitine palmitoyltransferase I-a was significantly lower in the FFA group than in the NC group(P<0.05),and the expression level in the FFA+EGCG group was significantly higher than that in the FFA group(P<0.05).Conclusion: EGCG can inhibit the expression of m RNA of DPP4 in NAFLD cells,increase the expression of m RNA of CPT1 a and PPARα,key enzymes of lipid oxidation,and improve triglyceride accumulation in hepatocytes.