Single cell landscape of functionally cured chronic hepatitis B patients reveals activation of innate and altered CD4-CTL-driven adaptive immunity

BACKGROUND & AIMS

Hepatitis B surface antigen (HBsAg) loss or functional cure (FC), is considered the desirable therapeutic outcome for chronic hepatitis B (CHB) patients. However, the immune-pathological biomarkers and underlying mechanisms remain unclear. In this study we comprehensively interrogate disease-associated cell states (DACS) identified within intra-hepatic tissue and matched PBMCs from either CHB or FC patients, at the resolution of single cells, to provide novel insights into putative mechanisms underlying FC.

METHODS

We combined single cell transcriptomics (scRNA-seq) with multiparametric flow cytometry-based immune phenotyping, and multiplexed immunofluorescence to elucidate the immunopathological cell states associated with CHB vs FC.

RESULTS

We find that the intra-hepatic environment of CHB and FC patients displays specific cell identities and molecular signatures that are distinct from those found in matched PBMCs. FC is associated with emergence of an altered adaptive immune response marked by CD4 cytotoxic T lymphocytes (CD4-CTLs), and an activated innate response represented by liver-resident natural killer (LR-NK) cells, specific Kupffer cell (KC) subtypes and marginated neutrophils. Surprisingly, we find that FC patients are also characterized by the presence of MHC class II-expressing hepatocytes and low but persistent levels of cccDNA and pgRNA, which may play an important role in achieving functional cure in HBV patients.

CONCLUSIONS

Our study provides conceptually novel insights into the immuno-pathological control of HBV cure, and opens exciting new avenues for clinical management, biomarker discovery and therapeutic interventions. We believe that the discoveries from this study, as it relates to the activation of an innate and altered immune response that may facilitate sustained, low-grade inflammation, may have broader implications in the resolution of chronic viral hepatitis.

Mitochondrial DNA is a target of HBV integration

Hepatitis B virus (HBV) may integrate into the genome of infected cells and contribute to hepatocarcinogenesis. However, the role of HBV integration in hepatocellular carcinoma (HCC) development remains unclear. In this study, we apply a high-throughput HBV integration sequencing approach that allows sensitive identification of HBV integration sites and enumeration of integration clones. We identify 3339 HBV integration sites in paired tumour and non-tumour tissue samples from 7 patients with HCC. We detect 2107 clonally expanded integrations (1817 in tumour and 290 in non-tumour tissues), and a significant enrichment of clonal HBV integrations in mitochondrial DNA (mtDNA) preferentially occurring in the oxidative phosphorylation genes (OXPHOS) and D-loop region. We also find that HBV RNA sequences are imported into the mitochondria of hepatoma cells with the involvement of polynucleotide phosphorylase (PNPASE), and that HBV RNA might have a role in the process of HBV integration into mtDNA. Our results suggest a potential mechanism by which HBV integration may contribute to HCC development.

Free episomal and integrated HBV DNA in HBsAg-negative patients with intrahepatic cholangiocarcinoma

There is evidence that chronic hepatitis B virus (HBV) infection is associated with an increased risk of intrahepatic cholangiocarcinoma (ICC) development, and it has been hypothesized an etiological role of HBV in the development of this tumor. Very little is known about occult HBV infection (OBI) in ICC. Aims of the study were to investigate the OBI prevalence and to characterize the HBV molecular status at intrahepatic level in OBI-positive cases with ICC.

Frozen liver tumor specimens from 47 HBV surface-antigen-negative patients with ICC and 41 paired non-tumor liver tissues were tested for OBI by 4 different HBV-specific nested PCR. Covalently closed circular HBV DNA (HBV cccDNA) and viral integrations were investigated in OBI-positive cases.

HBV DNA was detected in tumor and/or non-tumor specimens from 29/47 (61.7%) ICC patients. HBV cccDNA was found in tissues from 5/17 (34.5%) cases examined. HBV integration was detected in 4/10 (40%) tumor tissues tested and involved HBx and HBV-core gene sequences in 3 and 1 cases, respectively. Viral integration occurred: (a) 9,367 nucleotides upstream of the cat-eye-syndrome critical region protein-5-isoform coding sequence; (b) within the cystinosin isoform-1-precursor gene; (c) within the thromboxane-A-synthase-1 gene; (d) within the ATPase phospholipid transporting 9B gene.

Occult HBV infection is highly prevalent in patients with ICC. Both free viral genomes and integrated HBV DNA can be present in these cases. These results suggest an involvement of HBV in the carcinogenic process leading to ICC development even in cases with occult infection.

Evaluation of ibuprofen toxicity for zebrafish (Danio rerio) targeting on selected biomarkers of oxidative stress

OBJECTIVES

The aim of the study was to investigate the effects of subchronic exposure of zebrafish to ibuprofen, using selected oxidative stress parameters as a target.

DESIGN

Toxicity tests were performed on Danio rerio according to OECD No. 203 and No. 215. In the growth test, fish were exposed to subletal concentrations of ibuprofen (0.0001, 0.05, 1, 8, and 25 mg.L-1) for 28 days. For the assessment of free radical defense in fish, the catalytic activities of glutathione reductase (GR), glutathione S-transferase (GST), glutathione peroxidase (GPx), and catalase (CAT), as well as the concentration of malondialdehyde (MDA) were measured.

RESULTS

Ibuprofen did not affect the activity of glutathione reductase and catalase. A significant (p<0.01) increase in the activity of glutathione peroxidase was found, which was proved dose-dependent (10.58 nmol NADPH per min per mg protein in the control and 20.53, 26.36, 26.89, and 45.87 nmol NADPH per min per mg protein in the ibuprofen concentrations of 0.5, 1, 8, and 25 mg.L-1. An increased (p<0.05) activity of glutathione S-transferase in the highest concentration was found compared to control. Malondialdehyde levels were found significantly (p<0.01) decreased from control in the concentrations of 0.0001 and 8 mg.L-1, but no dose-dependence was found.

CONCLUSION

The results suggest that ibuprofen causes the increase in the activity of some antioxidative and biotransformation enzymes in zebrafish (GPx and GST). We also found a significant decrease in lipid peroxidation in the concentrations of 0.0001 and 8 mg.L-1 compared to control.