A functional variant ofCD40modulates clearance of hepatitis B virus in hepatocytes via regulation of the ANXA2/CD40/BST2 axis

Abstract

More than 250 million people in the world are chronically infected with hepatitis B virus (HBV), which causes serious complications. Host genetic susceptibility is essential for CHB, and our previous genome-wide association study identified a single-nucleotide polymorphism (SNP), rs1883832, in the 5′ untranslated region of CD40 predisposing to chronic HBV infection, but the underlying mechanism remains undefined. This study aimed to investigate whether rs1883832 was the real functional SNP (fSNP) of CD40 and how it modulated HBV clearance in hepatocytes. We determined the fSNP of CD40 and its regulatory protein(s) using luciferase reporter assays, electrophoretic mobility shift assay (EMSA), flanking restriction enhanced pulldown (FREP) and chromatin immunoprecipitation (ChIP). The potential anti-HBV activity of CD40 and its downstream molecule BST2 was assessed in HBV-transfected and HBV-infected hepatoma cells and HBV-infected primary human hepatocytes (PHHs). Moreover, the mechanism of CD40 was investigated by mRNA sequencing, quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence and western blot. We revealed rs1883832 as the true fSNP of CD40 and identified ANXA2 as a negative regulatory protein that preferentially bound to the risk allele T of rs1883832 and hence reduced CD40 expression. Furthermore, CD40 suppressed HBV replication and transcription in hepatocytes via activating the JAK–STAT pathway. BST2 was identified to be the key IFN-stimulated gene regulated by CD40 after activating JAK–STAT pathway. Inhibition of JAK/STAT/BST2 axis attenuated CD40-induced antiviral effect. In conclusion, a functional variant of CD40 modulates HBV clearance via regulation of the ANXA2/CD40/BST2 axis, which may shed new light on HBV personalized therapy.

Higher BST2 Expression Promotes the Anti‐HBV Effect of IFN‐α and BST2 Genetic Variant Predicts PegIFNα Treatment Response of HBeAg‐Positive Chronic Hepatitis B Patients

“…One possibility is that BST2 exerts anti‐HBV activity partly due to its blocking of intracellular virus budding. Moreover, we previously demonstrated that BST2 was regulated by the JAK–STAT pathway 22 . Other studies indicated that boosting the expression of methylated STAT1 and S‐adenosyl methionine might elevate IFNα's antiviral impact 34 .…”

“…We have previously identified that BST2 exerts an inhibitory effect on HBV. 22 It has been reported that BST2 is recognized as an IFN-stimulated gene (ISG), 23 indicating it may inhibit HBV replication due to being highly inducible by IFN in human hepatoma cells. Thus, we investigated whether IFN stimulation might alter BST2 expression.…”

“…Moreover, we previously demonstrated that BST2 was regulated by the JAK-STAT pathway. 22 Other studies indicated that boosting the expression of methylated STAT1 and S-adenosyl methionine might elevate IFNα's antiviral impact. 34 Hence, we hypothesized that BST2 strengthened HBV inhibition of IFN-α, possibly through the increased expression of methylated STAT1 and S-adenosyl methionine.…”

“…[18][19][20][21] Our previous study has identified that BST2 could block hepatitis B virus (HBV) replication and transcription. 22 However, the effect of BST2 on IFN-driven inhibition of HBV remains unknown. Furthermore, it is also unclear whether there are any genetic variants of BST2 associated with therapy response among patients with CHB who received PegIFNα.…”

“…Later, BST2 was also discovered to restrict the release of other enveloped viruses, including influenza virus, 14–16 herpesviruses, 17 and hepatitis C virus (HCV) 18–21 . Our previous study has identified that BST2 could block hepatitis B virus (HBV) replication and transcription 22 . However, the effect of BST2 on IFN‐driven inhibition of HBV remains unknown.…”