Hepatitis B virus upregulates host expression of α-1,2-mannosidasesviathe PPARα pathway

Abstract

AIMTo assess the effects of hepatitis B virus (HBV) on the expression of host α-1,2-mannosidases and determine the underlying mechanisms.METHODSWe measured the expression levels of MAN1A1, MAN1A2, MAN1B1, and MAN1C1 in cell lines HepG2.2.15, HepN10, HepAD38 and HepG2 by Western blot. Viral antigens (HBsAg and HBeAg) in the culture medium were measured using the chemiluminescence method. HBV DNA quantification assays were performed using a commercial real-time PCR kit. Protein levels of human liver tissue α-1,2-mannosidases were also evaluated by Western blot. Plasmids containing seven individual viral genes of HBV (PTT22-HBx, PTT22-HBs, PTT22-preS2, PTT22-preS1, PTT22-HBc, PTT22-HBe, and PTT22-HBp) or control plasmids (PTT22-vector) were transfected into HepG2 cells. MK886 (PPARα) and GW9662 (PPARγ) inhibitors were used to explore the effects of HBV on α-1,2-mannosidase expression after the PPARα and PPARγ pathways were blocked.RESULTSWe showed that the expression of α-1,2-mannosidases was higher in stably transfected HBV cells than in controls. The expression levels of α-1,2-mannosidase were higher in AD38 cells than those in ND10 cells, which were in turn greater than those in G2.2.15 cells, and positively correlated with the expression of HBsAg in all the cell lines. Levels of α-1,2-mannosidase in non-tumorous liver tissues of HBV-related HCC patients were also higher than in the tissues from non-HBV-related HCC patients. Moreover, transfecting HepG2 cells with a component of the HBV viral envelope also increased the expression of α-1,2-mannosidases. However, this envelope protein component could not induce MAN1C1 expression in the presence of a PPARα inhibitor, MK886. We also found that MK886 did not affect the expression of MAN1C1 in AD38 cells without tetracycline in the culture medium. This phenomenon was not observed in the case of GW9662.CONCLUSIONOur results indicate that HBV increases the expression of α-mannosidases both in vitro and in vivo via activation of the PPARα pathway by its envelope protein.

Hypoxia exacerbates nonalcoholic fatty liver disease via the HIF-2α/PPARα pathway

“…To mimic a hypoxic environment, cells were cultured in a hypoxia chamber with 1% O 2 for different durations (0, 12, 18, 24 h), as a previous study described (24). Fenofibrate (10 mol/L, Sigma-Aldrich) and MK886 (10 mol/L, Sigma-Aldrich), a selective PPAR␣ agonist and inhibitor, respectively, were utilized to activate or inhibit PPAR␣ according to the manufacturer's protocols (14,17).…”

Identification of cuproptosis-related molecular subtypes as a biomarker for differentiating active from latent tuberculosis in children

“…A previous study showed that α-mannosidase I ( MAN1C1 ) participates in cellular immunity during some chronic infections, such as HBV. The upregulation of a-mannosidase I expression manipulates the pathogens to escape immune recognition by DC-SIGN, inhibiting an efficient immune response and clearance of the etiologies [ 27 ]. SIRT4 resides within the mitochondria and belongs to the sirtuin (SIRT) family, with ADP-ribosyltransferase, lipoamidase, substrate-specific deacetylase, and deacetylase functions [ 28 ].…”

Preparation and functional evaluation of monoclonal antibodies targeting Hepatitis B Virus Polymerase

“…The following plasmids were used: Ptt22-HBV1.3, pAAV-HBV1.2, Ptt22-HBV pol and the control plasmid (Ptt22-mcherry). The preparation of these plasmids has been detailed in a previous study [ 15 ]. pTSMP-HBV1.3 plasmids with four different genotypes were a kind gift from yongwu, all of which expressed full length HBV [ 16 ].…”