Gene Regulation Analysis Of Effect Of Pomegranate Peel On Non-alcohol Fatty Liver Disease

Non-alcoholic fatty liver disease(NAFLD)is defined as a clinical syndrome that is characterized by excessive accumulation of fat in the liver cells,except for liver damage caused by alcohol and other factors.With the "two hit" hypothesis,insulin resistance(IR)is the first hit,while oxidative stress and lipid peroxidation are recognized as key factors as the second hit in the pathogensis of NAFLD.By now there have been many studies on the pathogenesis of NAFLD,but the specific pathogenesis of NAFLD is not clear yet.Therefore,an in-depth study on the pathogenesis of NAFLD is required for the development of more advanced methods of diagnosis and treatment.In recent years,pomegranate peel has been found to have effects of antioxidation and bacteriostasis,inhibiting the synthesis of fatty acid synthetase,regulating the balance of cholesterol in liver cells and reducing blood lipid.Therefore,we predict that pomegranate peel could be useful in the control of NAFLD.Exploring the molecular mechanism how pomegranate peel affecting NAFLD may futher clarify its function and provide a molecular basis for its further research and application.First of all,we collected the gene chip data set from the GEO database of NCBI,with the gene expression regulation of pomegranate peel on nonalcoholic fatty liver disease(NAFLD,GSE66316).We screened differentially expressed genes in rats fed on high fat diet with or without pomegranate peel by Qlucore Omics Explorer 3.0(QOE 3.0)software.Then DAVID,was used to classify the molecular functions of these differentially expressed genes.Finally,the Search Tool for the Retrieval of Interacting Genes/Proteins(STRING)analysis software was used to analyze the protein network of these differentially expressed genes.Through the analysis,we concluded that the regulation of NAFLD gene expression by pomegranate peel mainly focuses on a set of genes.We further mine the data from the published reports and reasoned that some of these genes may be the key for the pomegranate peer regulating the process of NAFLD.In more detail,QOE 3.0 analysis screened 172 differentially expressed genes.Among them,118 genes were upregulated after pomegranate peer application,including AAGAB,CAD,EXOC1,RPL10,TFB2M,RPS7,NHP2 and TRUB1;and 54 genes were down regulated,including ISG15,OASL,NR3C1,AZGP1,BIRC5 and RGMA.DAVID analysis showed that the functions of these differentially expressed genes were enriched in RNA biosynthesis and processing,ribosome complex,transport and localization,protein translation,single carbon metabolism,methylation,binding and activity of GTPase,calcium ion binding,polysaccharide binding,regulation of enzyme activity of nucleoside triphosphatase,transcription coactiveator,transcription factor binding,ribonucleoprotein complex,mitochondria and biological functions of lipoprotein.In this paper,172 differentially expressed genes obtained from QOE 3.0 were further analyzed by using STRING,combined with the results of the DAVID analysis.Subsequently,.13 differentially expressed genes were screened to be related with treatment of NAFLD by pomegranate peel,including CAD,C1QBP,RPL10,RPS7,NHP2,CARM1,LPL,TFB2M,TRUB1,PCK2,NR3C1,ISG15,OASL.Among them,NR3C1,ISG15 and OASL are down regulated in pomegranate peel group,while others were up regulated.Further data mining from published reports and databases and analysis with these genes showed that the treatment of pomegranate peel for NAFLD mainly promote hydrolysis of triglycerides,reduce accumulation of triglycerides in liver,strengthen oxidative stresss resistance of liver cells and maintain the stability of the mitochondrial function.All these activities are necessary for maintaining the biochemical metabolism of liver cells.Meanwhile,the analysis also indicated that pomegranate peel may reduce concentration of free fatty acid in blood,and relieve the insulin resistance.These analyses preliminarily showed the mechanism how pomegranate peel achieved the effect on remedying NAFLD,which will be helpful for further and potential clinical application of pomegranate peel.