Effect Of PCA On The Expression Of HNF1? And The Mechanism Of Anti-HBV Research In Vitro

Chronic hepatitis B virus is a multiple infectious diseases in China.Currently,3TC is one of the major nucleoside analogues used for clinical treatment of HBV.It can highly suppress HBV DNA with rapid onset and low toxicity.However,it is extremely easy to relapse after drug withdrawal and long-term use will easily lead to drug resistance.3TC+ PCA is a kind of combination drug screened by our research group,which has synergistic inhibitory effect composition on HBV DNA and HBV antigens in HepG2.2.15 cell.Our previous study showed that 3TC+PCA can enhance the inhibitory effect of 3TC on duck hepatitis B virus(DHBV)DNA and improve liver function and the rebound phenomenon of the virus after drug withdrawal.In addition,it can down-regulate the absorption rate of 3TC and the elimination and the absorption rate of PCA in rats and increase the absorption amount of 3TC.What's more,3TC+PCA can strengthen the inhibiting ability of 3TC on DHBV's adsorption and infection on hepatocytes,the activities of HBV promoters,as well as the distribution of HBV X protein in cellular nucleus.Meanwhile,PCA is able to inhibit the expression of HNF4a and the activities of HBV core,X and preS1 promoter,which is an important mechanism produced by the combination of the two drugs to resist HBV.However,the anti-HBV mechanism of PCA has not been well elucidated at present.HNF 1? and HNF4a can not only regulate the expression of specific genes of hepatocytes and make hepatocytes play a role of transcription factors,but also combine with the HBV promoters/enhancers so as to play an important regulatory role in the transcription and replication of HBV gene.This paper studied the effects of PCA on the expression of the HNF 1? and the anti-HBV mechanism of PCA.The tests show that:(1)After Huh7 cells and HepG2.2.15 cells respectively had been incubating with PCA(0.1-10?g/mL)for 24h or 48h,PCA(10?g/mL)significantly inhibited the expression of mRNA and protein of HNF 1?.(2)It was known that the activated ERK pathway could down-regulate the expression of HNF4? and HNF1? and suppress the replication of HBV at the transcriptional level.Treated with PCA(10?g/mL)for 48 hours could obviously induce the phosphorylation of ERK in HepG2,2.15 cells,but had no effect on Huh7 cells,which indicated that PCA could specifically activate the ERK pathway in HepG2.2.15 cell.(3)U0126,the specific inhibitors of the ERK pathway,could block PCA's activation of ERK pathway and eliminate the suppression of PCA on HNF4a and HNFla.In conclusion,we suggest the anti-HBV mechanism of PCA in HepG2.2.15 cells is that:By activating ERK pathway,PCA decrease the interaction between HNF4?,HNF1?,the HBV core and(or)preS1 promoter and enhancers by down-regulating the expression of HNF4a and HNFla that are closely related to the replication of HBV,and then suppress the activity of HBV promoters;finally,suppress the replication of HBV.