Effect And Mechanism Of Tenofovir Disoproxil Fumarate On Improving Chronic Liver Diseases And Reducing Blood Lipids

Objective: For untreated chronic hepatitis B(CHB)patients,higher baseline serum hepatitis B virus(HBV)DNA levels were associated with greater risk of developing chronic liver diseases(CLDs).Tenofovir disoproxil fumarate(TDF)and entecavir(ETV)are both current first-line oral antiviral drugs,both of which can reduce the risk of developing CLDs in CHB patients by inhibiting HBV replication.Although TDF and ETV have comparable antiviral efficacy,their effects on the progression of CLDs are different.Studies have shown that TDF has an additional immuneinducing effect,a higher rate of early normalization of alanine aminotransferase(ALT),and a better lipid profile than ETV.And immunity,inflammation and metabolism play important roles in the occurrence and development of CLDs.Therefore,we hypothesized that TDF may exert additional pharmacological effects by affecting immune,inflammatory and metabolic processes in the liver in addition to antiviral effects.Studies have shown that TDF can directly improve liver fibrosis and reduce blood lipids,but such studies are still relatively limited and there are few studies involving its mechanism.Therefore,this study aimed to use the liver transcriptomic data of TDF-treated normal mice to explore the effect and mechanism of TDF directly improving CLDs and reducing blood lipids.Methods: Wild-type C57BL/6J mice were randomly divided into Control group and TDF group.Mice in TDF group were intragastrically administered TDF solution(45.5 mg/kg)every day,while mice in Control group were intragastrically administered an equal volume of sodium carboxymethylcellulose solution.Lasts 4 months.At the end of the experiment,general parameters of mice were detected and transcriptome sequencing(RNA-Seq)was performed on mouse liver tissue.Based on this sequencing data,the study was divided into two parts:1.To explore the possible targets and mechanisms of TDF in directly improving CLDs:(1)Screening of significantly differentially expressed genes(DEGs);(2)Functional enrichment analysis of DEGs;(3)By constructing the protein-protein interaction(PPI)network of DEGs,important functional modules and key gene networks,key genes were selected;(4)Dis Ge NET was used to query and screen possible target genes for TDF in improving CLDs;(5)Predicting the upstream transcription factors(TFs)and micro RNAs(mi RNAs)of target genes,and constructing mi RNAs-TFs co-regulatory network map of target genes.2.Exploring the hypolipidemic effect and mechanism of TDF:(1)GSEA was used to perform functional enrichment analysis of all genes,and by paying attention to the impact of TDF on the biological processes and pathways related to triglyceride(TG)and cholesterol(TC)metabolism,potential target genes were screened;(2)In vitro cell experiments were performed to observe the effect of TDF on the levels of TG and TC in the cell culture supernatant;(3)The m RNA levels of potential target genes were detected by real time PCR.Results: 1.Exploring the possible targets and mechanisms of TDF in directly improving CLDs:(1)Compared with the Control group,TDF induced a total of 854 genes that were significantly differentially expressed,and these DEGs were mainly enriched in immune,inflammatory and metabolic processes;(2)50 key genes were screened out from 854 DEGs,which also mainly play roles in immune,inflammatory and metabolic processes;(3)19 genes were screened out of 50 key genes which may be the target genes for TDF to improve CLDs;(4)mmu-mi R-155-5p and Nfkb1 may be key upstream regulators of these target genes.2.To explore the hypolipidemic effect and mechanism of TDF:(1)The enrichment analysis results showed that TDF significantly inhibited the intermediate process of TG synthesis-fatty acid biosynthesis,but had no significant effect on the TC metabolic process;(2)The enrichment analysis results showed that TDF may inhibit fatty acid biosynthesis by inhibiting the expression of fatty acid synthesis genes(Fasn,Acaca)and desaturation genes(Fads2,Fads1,Scd1),thereby reducing TG;(3)In vitro cell experiments showed that TDF significantly reduced TG in cell culture supernatant,but had no significant effect on TC;(4)In vitro cell experiments showed that TDF significantly inhibited the expression of fatty acid synthesis genes(Acaca)and desaturation genes(Fads2,Fads1,Scd1).Conclusions: In the liver,TDF may have other pharmacological effects besides antiviral effects.First,TDF may affect the expression of genes involved in liver immune,inflammatory and metabolic processes through the mmu-mi R-155-5p-NF-κB signaling pathway,thereby directly improving CLDs.Second,TDF can lower blood TG by directly inhibiting TG synthesis.