CXCL8, CXCL9, CXCL10, and CXCL11 as biomarkers of liver injury caused by chronic hepatitis B

Structural properties of immune complexes formed by viral antigens and specific antibodies shape the inflammatory response of macrophages

Data on the course of viral infections revealed severe inflammation as a consequence of antiviral immune response. Despite extensive research, there are insufficient data on the role of innate immune cells in promoting inflammation mediated by immune complexes (IC) of viral antigens and their specific antibodies. Recently, we demonstrated that antigens of human polyomaviruses (PyVs) induce an inflammatory response in macrophages. Here, we investigated macrophage activation by IC. We used primary murine macrophages as a cell model, virus-like particles (VLPs) of PyV capsid protein as antigens, and a collection of murine monoclonal antibodies (mAbs) of IgG1, IgG2a, IgG2b subclasses. The inflammatory response was investigated by analysing inflammatory chemokines and activation of NLRP3 inflammasome. We observed a diverse pattern of chemokine secretion in macrophages treated with different IC compared to VLPs alone. To link IC properties with cell activation status, we characterised the IC by advanced optical and acoustic techniques. Ellipsometry provided precise real-time kinetics of mAb-antigen interactions, while quartz crystal microbalance measurements showed changes in conformation and viscoelastic properties during IC formation. These results revealed differences in mAb-antigen interaction and mAb binding parameters of the investigated IC. We found that IC-mediated cell activation depends more on IC characteristics, including mAb affinity, than on mAb affinity for the activating Fc receptor. IC formed by the highest affinity mAb showed a significant enhancement of inflammasome activation. This may explain the hyperinflammation related to viral infection and vaccination. Our findings demonstrate that IC promote the viral antigen-induced inflammatory response depending on antibody properties.

Establishment and characterization of cytochrome P450 1A1 CRISPR/Cas9 Knockout Bovine Foetal Hepatocyte Cell Line (BFH12)

The cytochrome P450 1A (CYP1A) subfamily of xenobiotic metabolizing enzymes (XMEs) consists of two different isoforms, namely CYP1A1 and CYP1A2, which are highly conserved among species. These two isoenzymes are involved in the biotransformation of many endogenous compounds as well as in the bioactivation of several xenobiotics into carcinogenic derivatives, thereby increasing the risk of tumour development. Cattle (Bos taurus) are one of the most important food-producing animal species, being a significant source of nutrition worldwide. Despite daily exposure to xenobiotics, data on the contribution of CYP1A to bovine hepatic metabolism are still scarce. The CRISPR/Cas9-mediated knockout (KO) is a useful method for generating in vivo and in vitro models for studying xenobiotic biotransformations. In this study, we applied the ribonucleoprotein (RNP)-complex approach to successfully obtain the KO of CYP1A1 in a bovine foetal hepatocyte cell line (BFH12). After clonal expansion and selection, CYP1A1 excision was confirmed at the DNA, mRNA and protein level. Therefore, RNA-seq analysis revealed significant transcriptomic changes associated with cell cycle regulation, proliferation, and detoxification processes as well as on iron, lipid and mitochondrial homeostasis. Altogether, this study successfully generates a new bovine CYP1A1 KO in vitro model, representing a valuable resource for xenobiotic metabolism studies in this important farm animal species.

Associations of Wnt5a expression with liver injury in chronic hepatitis B virus infection

BACKGROUND

Aberrant Wnt5a expression contributes to immunity, inflammation and tissue damage. However, it remains unknown whether Wnt5a is associated with liver injury in chronic hepatitis B virus (HBV) infection. We aimed to explore the potential role of Wnt5a expression in liver injury caused by chronic HBV infection.

METHODS

Wnt5a mRNA levels in peripheral blood mononuclear cells (PBMCs) were analyzed in 31 acute-on-chronic hepatitis B liver failure (ACHBLF) patients, 82 chronic hepatitis B (CHB) patients, and 20 healthy controls using quantitative real-time polymerase chain reaction. Intrahepatic Wnt5a protein expression from 32 chronic HBV infection patients and 6 normal controls was evaluated by immunohistochemical staining.

RESULTS

Wnt5a mRNA expression was increased in CHB patients and ACHBLF patients compared to healthy controls and correlated positively with liver injury markers. Additionally, there was a significant correlation between Wnt5a mRNA expression and HBV DNA load in all patients and CHB patients but not in ACHBLF patients. Furthermore, intrahepatic Wnt5a protein expression was elevated in chronic HBV infection patients compared to that in normal controls. Moreover, chronic HBV infection patients with higher hepatic inflammatory grades had increased intrahepatic Wnt5a protein expression compared with lower hepatic inflammatory grades. In addition, the cut-off value of 12.59 for Wnt5a mRNA level was a strong indicator in predicting ACHBLF in CHB patients.

CONCLUSIONS

We found that Wnt5a expression was associated with liver injury in chronic HBV infection patients. Wnt5a might be involved in exacerbation of chronic HBV infection.

AhR may be involved in Th17 cell differentiation in chronic hepatitis B

Th17 cells which are crucial for host immunity have been demonstrated to increase HBV infection. However, the mechanism of the Th17 cell increase is unknown. Hence, the mechanism of Th17 cell enhancement is important to provide a theoretical foundation for chronic hepatitis B immunotherapy. This study included 15 instances in the healthy control (HC) and 15 cohorts in the chronic hepatitis B (CHB). Their CD4+ T cells were isolated from their peripheral blood and then subjected to RNA transcriptome sequencing. Then, to identify target genes linked to Th17-cell differentiation, DEGs associated with CHB were convergent with the Th17-cell-associated genes from the KEGG database. Hub genes of DEG and target genes linked to Th17 cells were analysed for correlation. The AhR-related genes were located using the GeneMANIA database. To analyse the function of the genes, GO and KEGG pathways were employed. Protein-protein interaction network analysis employed the Metascape, STRING and Cytoscape databases. Finally, Western blotting and RT-qPCR were used to validate AhR. A total of 348 differential genes were identified in CHB patients. CytoHubba was used for screening five hub genes associated with CHB: CXCL10, RACGAP1, TPX2, FN1 and GZMA. This study aimed to determine the mechanism of elevated Th17 cells in CHB. As a result, further investigation using the convergence of DGEs and Th17 cell-related genes identified three target genes: AhR, HLA-DQA1 and HLA-DQB1, all of which were elevated in CHB. The three genes were primarily involved in immune response-related processes, according to the GO enrichment analysis. Correlation analysis of CXCL10, RACGAP1, TPX2, FN1 and GZMA genes with AhR, HLA-DQA1 and HLA-DQB1 revealed that AhR was positively associated with CXCL10 and GZMA genes, which best respond to the severity of CHB disease. Combined with the role of AhR in Th17 cell differentiation, the genes AhR was chosen for confirmation by RT-qPCR and WB in this study. The results showed that the CHB group had higher expression levels of AhR at both RT-qPCR and WB levels. Furthermore, this study's findings revealed that AhR may contribute to the development of CHB by affecting the differentiation of Th17 cells.

SUV39H1 is a novel biomarker targeting oxidative phosphorylation in hepatitis B virus-associated hepatocellular carcinoma

BACKGROUND

As a histone methyltransferase, suppressor of variegation 3-9 homolog 1 (SUV39H1) plays an important role in the occurrence and development of cancer. To explore the mechanism and biological function of SUV39H1 in hepatitis B virus-associated hepatocellular carcinoma (HBV-HCC) can gain an insight into the pathogenesis of HBV-HCC.

METHODS

The effect of HBV infection on SUV39H1 in hepatoma cells was detected. CCK-8, colony growth assay and wound healing assay were used to assess the proliferation and migration of HBV-positive hepatoma cells. RNA sequencing (RNA-seq) was applied to find differential genes and enriched pathways. The serum SUV39H1 level in HBV-HCC patients was detected and its correlation with clinical indicators was analyzed.

RESULTS

SUV39H1 was increased by HBV infection and promoted the proliferation and migration of hepatoma cells. SUV39H1 could upregulate the expression of mitochondrial oxidative phosphorylation (OXPHOS) pathway-related genes. OXPHOS pathway inhibitors could reduce the capacity of proliferation and migration of hepatoma cells after overexpressing SUV39H1. Serum SUV39H1 levels were higher in chronic hepatitis B (CHB) patients than in healthy controls and higher in HBV-HCC patients than in CHB patients. In the diagnosis of HCC, the predictive value of SUV39H1 combined with alpha-fetoprotein (AFP) was better than that of AFP alone.

CONCLUSION

SUV39H1 is regulated by HBV infection and promotes the proliferation and migration of hepatoma cells by targeting OXPHOS pathway. It indicates that SUV39H1 may be a new biomarker of the diagnosis of HCC.

Identification of interferon-stimulated genes with modulated expression during hepatitis E virus infection in pig liver tissues and human HepaRG cells

Introduction

Hepatitis E virus (HEV) is a common cause of enterically transmitted acute hepatitis worldwide. The virus is transmitted by the fecal-oral route via the consumption of contaminated water supplies and is also a zoonotic foodborne pathogen. Swine are the main reservoir of zoonotic HEV. In humans, HEV infection is usually asymptomatic or causes acute hepatitis that is self-limited. However, fulminant hepatic failure and chronic cases of HEV infection can occur in some patients. In contrast, HEV infection in pigs remains asymptomatic, although the virus replicates efficiently, suggesting that swine are able to control the virus pathogenesis. Upon viral infection, IFN is secreted and activates cellular pathways leading to the expression of many IFN-stimulated genes (ISGs). ISGs can restrict the replication of specific viruses and establish an antiviral state within infected and neighboring cells.

Methods

In this study, we used PCR arrays to determine the expression level of up to 168 ISGs and other IFN-related genes in the liver tissues of pigs infected with zoonotic HEV-3c and HEV-3f and in human bipotent liver HepaRG cells persistently infected with HEV-3f.

Results and discussion

The expression of 12 and 25 ISGs was found to be up-regulated in infected swine livers and HepaRG cells, respectively. The expression of CXCL10, IFIT2, MX2, OASL and OAS2 was up-regulated in both species. Increased expression of IFI16 mRNA was also found in swine liver tissues. This study contributes to the identification of potential ISGs that could play a role in the control or persistence of HEV infection.

The role of CXCL family members in different diseases

Chemokines are a large family mediating a lot of biological behaviors including chemotaxis, tumor growth, angiogenesis and so on. As one member of this family, CXC subfamily possesses the same ability. CXC chemokines can recruit and migrate different categories of immune cells, regulate tumor's pathological behaviors like proliferation, invasion and metastasis, activate angiogenesis, etc. Due to these characteristics, CXCL subfamily is extensively and closely associated with tumors and inflammatory diseases. As studies are becoming more and more intensive, CXCLs' concrete roles are better described, and CXCLs' therapeutic applications including biomarkers and targets are also deeply explained. In this review, the role of CXCL family members in various diseases is summarized.

Serum CXCL5 Detects Early Hepatocellular Carcinoma and Indicates Tumor Progression

Chemokines or chemotactic cytokines play a pivotal role in the immune pathogenesis of liver cirrhosis and hepatocellular carcinoma (HCC). Nevertheless, comprehensive cytokine profiling data across different etiologies of liver diseases are lacking. Chemokines might serve as diagnostic and prognostic biomarkers. In our study, we analyzed serum concentrations of 12 inflammation-related chemokines in a cohort of patients (n = 222) with cirrhosis of different etiologies and/or HCC. We compared 97 patients with cirrhosis and treatment-naïve HCC to the chemokine profile of 125 patients with cirrhosis but confirmed absence of HCC. Nine out of twelve chemokines were significantly elevated in sera of cirrhotic patients with HCC compared to HCC-free cirrhosis controls (CCL2, CCL11, CCL17, CCL20, CXCL1, CXCL5, CXCL9, CXCL10, CXCL11). Among those, CXCL5, CXCL9, CXCL10, and CXCL11 were significantly elevated in patients with early HCC according to the Barcelona Clinic Liver Cancer (BCLC) stages 0/A compared to cirrhotic controls without HCC. In patients with HCC, CXCL5 serum levels were associated with tumor progression, and levels of CCL20 and CXCL8 with macrovascular invasion. Importantly, our study identified CXCL5, CXCL9, and CXCL10 as universal HCC markers, independent from underlying etiology of cirrhosis. In conclusion, regardless of the underlying liver disease, patients with cirrhosis share an HCC-specific chemokine profile. CXCL5 may serve as a diagnostic biomarker in cirrhotic patients for early HCC detection as well as for tumor progression.