Interferon-stimulated gene 15 in hepatitis B-related liver diseases

Chasing Virus Replication and Infection: PAMP-PRR Interaction Drives Type I Interferon Production, Which in Turn Activates ISG Expression and ISGylation

The innate immune response, particularly the interferon-mediated pathway, serves as the first line of defense against viral infections. During virus infection, viral pathogen-associated molecular patterns (PAMPs) are recognized by host pattern recognition receptors (PRRs), triggering downstream signaling pathways. This leads to the activation of transcription factors like IRF3, IRF7, and NF-κB, which translocate to the nucleus and induce the production of type I interferons (IFN-α and IFN-β). Once secreted, type I interferons bind to their receptors (IFNARs) on the surfaces of infected and neighboring cells, activating the JAK-STAT pathway. This results in the formation of the ISGF3 complex (composed of STAT1, STAT2, and IRF9), which translocates to the nucleus and drives the expression of interferon-stimulated genes (ISGs). Some ISGs exert antiviral effects by directly or indirectly blocking infection and replication. Among these ISGs, ISG15 plays a crucial role in the ISGylation process, a ubiquitin-like modification that tags viral and host proteins, regulating immune responses and inhibiting viral replication. However, viruses have evolved counteractive strategies to evade ISG15-mediated immunity and ISGylation. This review first outlines the PAMP-PRR-induced pathways leading to the production of cytokines and ISGs, followed by a summary of ISGylation's role in antiviral defense and viral evasion mechanisms targeting ISG15 and ISGYlation.

Exploring the role of the IL-12/IFN-γ immune axis in subacute sclerosing panencephalitis

BACKGROUND

Subacute sclerosing panencephalitis (SSPE) is a rare but fatal neurological syndrome resulting from persistent measles virus infection in the central nervous system. Despite the availability of a measles vaccine, SSPE continues to pose a significant health burden, and immunogenetic risk factors remain unclear. We aimed to study the role of the interleukin 12 (IL-12)/interferon-gamma (IFN-γ) axis, known for it's significance in antiviral defense, in the development of SSPE.

METHODS

This cross-sectional case-control study recruited consecutive age and sex-matched SSPE cases (n = 51) and controls (n = 51). Gene expressions were quantified for IL-12B, IFNG, IL-12RB1, STAT4, IFNGR1, IFNGR2, STAT1, IRF8, and ISG15 genes using quantitative realtime PCR. Additionally, plasma levels of IL-12p40, IL-12p70, and IFN-γ were measured using the multiplex suspension array platform. Furthermore, single nucleotide polymorphisms (SNPs) in IL-12B, IL-12RB1, IFNG, IFNGR1, IFNGR2, and ISG15 genes were examined using TaqMan SNP genotyping assays. Statistical analyses compared gene expressions, cytokine levels, and alleles and genotypes frequencies between SSPE patients and controls.

RESULTS

Significant alterations in the expression of key IL-12 pathway-related genes were observed in SSPE patients compared to controls, including lower STAT4 (p = 0.0445) and higher IFNGR1 (p = 0.0005) and IRF8 (p = 0.0229). Elevated plasma levels of IL-12p70 (p = 0.0015) and IFN-γ (p = 0.0381) were also observed in SSPE patients. Additionally, associations with SSPE were found for the rs3212227 SNP in IL-12B (p = 0.048), the rs1059293 SNP in IFNGR2 (p = 0.052), and the rs1921 SNP in ISG15 (p = 0.054) genes. Notably, gene-gene interactions among these genes exhibited associations with SSPE.

CONCLUSION

This study provides novel insights into the dysregulation of the IL-12/IFN-γ immune axis in SSPE and underscores the complex interplay between host genetics and viral infection in disease pathogenesis.

Interferon-stimulated gene 15 polymorphisms are associated with spontaneous preterm birth in Taiwanese women

PROBLEM

Immune and inflammatory responses are known to be major causes of preterm birth (PTB). The maternal genetic background plays an important role in the development of PTB. Interferon-stimulated gene 15 (ISG15) is an interferon-induced protein which can modulate immune cell activation and function. We aim to study if polymorphisms in the ISG15 gene are associated with spontaneous PTB (sPTB) risk in Taiwanese women.

METHOD OF STUDY

ISG15 rs4615788 C/G, rs1921 G/A, and rs8997 A/G polymorphisms were genotyped in a hospital-based study of 112 women with sPTB and 1120 term controls. The plasma concentrations of ISG15 were determined by enzyme-linked immunosorbent assay.

RESULTS

We found the ISG15 rs1921 G-rs8997 A haplotype was associated with decreased risk for PTB (χ2  = 6.26, p = .01, pc  = .04). The A/G genotype of ISG15 rs8997 polymorphism might have the potential to confer reduced risk of PTB women (χ2  = 4.09, p = .04, pc  = .08). Spontaneous PTB women displayed higher plasma ISG15 levels compared to term controls (p < .001). The plasma ISG15 levels among pregnant women with rs8997 A/G genotype were found significantly lower compared to G/G genotype (p = .03).

CONCLUSIONS

Women with the ISG15 rs1921 G-rs8997 A haplotype may associate with spontaneous PTB. These findings provide new insights into the etiology of preterm birth.

Transcriptome wide functional analysis of HBx expressing human hepatocytes stimulated with endothelial cell cross-talk

Identification of genes dysregulated during the hepatitis B virus (HBV)-host cell interaction adds to the understanding of underlying molecular mechanisms and aids in discovering effective therapies to improve prognosis in hepatitis B virus (HBV)-infected individuals. Through bioinformatics analyses of transcriptomics data, this study aimed to identify potential genes involved in the cross-talk of human hepatocytes expressing the HBV viral protein HBx with endothelial cells. Transient transfection of HBV viral gene X (HBx) was performed in THLE2 cells using pcDNA3 constructs. Through mRNA Sequencing (RNA Seq) analysis, differentially expressed genes (DEGs) were identified. THLE2 cells transfected with HBx (THLE2x) were further treated with conditioned medium from cultured human umbilical vein derived endothelial cells (HUVEC-CM). Gene Ontology (GO) enrichment analysis revealed that interferon and cytokine signaling pathways were primarily enriched for the downregulated DEGs in THLE2x cells treated with HUVEC-CM. One significant module was selected following protein-protein interaction (PPI) network generation, and thirteen hub genes were identified from the module. The prognostic values of the hub genes were evaluated using Kaplan-Meier (KM) plotter, and three genes (IRF7, IFIT1, and IFITM1) correlated with poor disease specific survival (DSS) in HCC patients with chronic hepatitis. A comparison of the DEGs identified in HUVEC-stimulated THLE2x cells with four publicly available HBV-related HCC microarray datasets revealed that PLAC8 was consistently downregulated in all four HCC datasets as well as in HUVEC-CM treated THLE2x cells. KM plots revealed that PLAC8 correlated with worse relapse free survival and progression free survival in HCC patients with hepatitis B virus infection. This study provided molecular insights which may help develop a deeper understanding of HBV-host stromal cell interaction and open avenues for future research.

Efficacy and safety of vesatolimod in chronic hepatitis B: A systematic review and meta-analysis

BACKGROUND

Vesatolimod is a toll-like receptor (TLR) agonist that is thought to suppress chronic hepatitis B (HBV) infection. This systematic review aimed to assess the safety and efficacy of vesatolimod in treating chronic hepatitis B.

METHODS

We included randomized clinical trials (RCTs) that assessed vesatolimod in patients with hepatitis B infection without hepatocellular carcinoma or liver transplantation and with reported levels of hepatitis B surface antigen (HBsAg) or liver transaminases post-intervention. We searched MEDLINE, SCOPUS, Springer, Google Scholar, ClinicalTrials.gov, and Cochrane Central Register of Clinical Trials for all related articles during May 2022. Two independent authors screened articles for inclusion, and discrepancies were resolved by consensus and a third reviewer. Two independent reviewers assessed studies included in this systematic review using the Critical Appraisal Skills Programme checklist for RCTs.

RESULTS AND CONCLUSION

Only 4 were considered eligible from 391 articles identified through our search. All eligible studies did not report any clinically significant outcomes following the use of vesatolimod, as evidenced by the persistence of HBsAg. However, vesatolimod was associated with induction of interferon-stimulated genes (ISGs) and only mild side effects, warranting further studies to evaluate its potential for future use as a safe, tolerable anti-HBV medication. No significant differences were noted amongst trials included in either of Vesatolimod doses (Vesatolimod 1 mg, RR = 0.99, 95% CI 0.76-1.30, P = .95, I2 = 0%; Vesatolimod 2 mg, RR = 1.06, 95% CI 0.82-1.37, P = .66, I2 = 0%; Vesatolimod 4 mg, RR = 1.06, 95% CI 0.82-1.37, P = .66, I2 = 0%;), further suggesting its comparable safety in comparison to oral antiviral agents.

HERC5 E3 ligase mediates ISGylation of hepatitis B virus X protein to promote viral replication

Ubiquitin and ubiquitin-like protein modification play important roles in modulating the functions of viral proteins in many viruses. Here we demonstrate that hepatitis B virus (HBV) X protein (HBx) is modified by ISG15, which is a type I IFN-inducible, ubiquitin-like protein; this modification is called ISGylation. Immunoblot analyses revealed that HBx proteins derived from four different HBV genotypes accepted ISGylation in cultured cells. Site-directed mutagenesis revealed that three lysine residues (K91, K95 and K140) on the HBx protein, which are well conserved among all the HBV genotypes, are involved in acceptance of ISGylation. Using expression plasmids encoding three known E3 ligases involved in the ISGylation to different substrates, we found that HERC5 functions as an E3 ligase for HBx-ISGylation. Treatment with type I and type III IFNs resulted in the limited suppression of HBV replication in Hep38.7-Tet cells. When cells were treated with IFN-α, silencing of ISG15 resulted in a marked reduction of HBV replication in Hep38.7-Tet cells, suggesting a role of ISG15 in the resistance to IFN-α. In contrast, the silencing of USP18 (an ISG15 de-conjugating enzyme) increased the HBV replication in Hep38.7-Tet cells. Taken together, these results suggest that the HERC5-mediated ISGylation of HBx protein confers pro-viral functions on HBV replication and participates in the resistance to IFN-α-mediated antiviral activity.

Genetic variants of programmed cell death 1 are associated with HBV infection and liver disease progression

The inhibitory effects of programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) modulates T-cell depletion. T-cell depletion is one of the key mechanisms of hepatitis B virus (HBV) persistence, in particular liver disease progression and the development of hepatocellular carcinoma (HCC). This case–control study aimed to understand the significance of PD-1 polymorphisms (PD-1.5 and PD-1.9) association with HBV infection risk and HBV-induced liver disease progression. Genotyping of PD-1.5 and PD-1.9 variants was performed by direct Sanger sequencing in 682 HBV-infected patients including chronic hepatitis (CHB, n = 193), liver cirrhosis (LC, n = 183), hepatocellular carcinoma (HCC, n = 306) and 283 healthy controls (HC). To analyze the association of PD-1 variants with liver disease progression, a binary logistic regression, adjusted for age and gender, was performed using different genetic models. The PD-1.9 T allele and PD-1.9 TT genotype are significantly associated with increased risk of LC, HCC, and LC + HCC. The frequencies of PD-1.5 TT genotype and PD-1.5 T allele are significantly higher in HCC compared to LC patients. The haplotype CT (PD-1.5 C and PD-1.9 T) was significantly associated with increased risk of LC, HCC, and LC + HCC. In addition, the TC (PD-1.5 T and PD-1.9 C) haplotype was associated with the risk of HCC compared to non-HCC. The PD-1.5 CC, PD-1.9 TT, genotype, and the CC (PD-1.5 C and PD-1.9) haplotype are associated with unfavorable laboratory parameters in chronic hepatitis B patients. PD-1.5 and PD1.9 are useful prognostic predictors for HBV infection risk and liver disease progression.

Natural killer cell receptor variants and chronic hepatitis B virus infection in the Vietnamese population

OBJECTIVES

Genes of host immunity play an important role in disease pathogenesis and are determinants of clinical courses of infections, including hepatitis B virus (HBV). Killer-cell immunoglobulin-like receptor (KIR), expressed on the surface of natural killer cells (NK), regulate NK cell cytotoxicity by interacting with human leukocyte antigen (HLA) class I molecules and are candidates for influencing the course of HBV. This study evaluated whether variations in KIR gene content and HLA-C ligands are associated with HBV and with the development of liver cirrhosis and hepatocellular carcinoma.

METHODS

A Vietnamese study cohort (HBV n = 511; controls n = 140) was genotyped using multiplex sequence-specific polymerase chain reaction (PCR-SSP) followed by melting curve analysis.

RESULTS

The presence of the functional allelic group of KIR2DS4 was associated with an increased risk of chronic HBV (OR = 1.86, p^corr = 0.02), while KIR2DL2+HLA-C1 (OR = 0.62, p^corr = 0.04) and KIR2DL3+HLA-C1 (OR = 0.48, p^corr = 0.04) were associated with a decreased risk. The pair KIR2DL3+HLA-C1 was associated with liver cirrhosis (OR = 0.40, p^corr = 0.01). The presence of five or more activating KIR variants was associated with hepatocellular carcinoma (OR = 0.53, p^corr = 0.04).

CONCLUSIONS

KIR gene content variation and combinations KIR-HLA influence the outcome of HBV infection.

Upregulation of Enzymes involved in ISGylation and Ubiquitination in patients with hepatocellular carcinoma

Background: ISGylation is the conjugation of ISG15 with target proteins. ISGylation occurs through an enzymatic cascade, which is similar to that of ubiquitination. Through ISGylation, ISG15 can bind to proteins involved in cell proliferation and differentiation, thus promoting genesis and progression of malignancies. The present study aims to investigate expression of genes involved in ISGylation and ubiquitination in patients with hepatocellular carcinoma and to correlate gene expression with clinical laboratory parameters of these patients. Methods: mRNA expression of genes encoding enzymes involved in the ISGylation process (EFP, HERC5, UBA1, UBC and USP18) was evaluated by quantitative real-time PCR in 38 pairs of tumour and adjacent non-tumour tissues from patients with hepatocellular carcinoma and correlated with distinct clinical laboratory parameters. Results: Relative mRNA expression of EFP, HERC5, UBA1 and USP18 was significantly higher in tumour tissues compared to adjacent non-tumour tissues (P=0.006; 0.012; 0.02 and 0.039, respectively). The correlation pattern of mRNA expression between genes in the tumours differed from the pattern in adjacent non-tumour tissues. Relative expression of EFP, HERC5 and UBA1 in adjacent non-tumour tissues was positively associated with direct bilirubin levels (Spearman's rho=0.31, 0.33 and 0.45; P=0.06, 0.05 and 0.01, respectively) and relative expression of USP18 in adjacent non-tumour tissues correlated negatively with ALT levels (Spearman's rho= -0.33, P=0.03). Conclusions: EFP, HERC5, UBA1, and USP18 genes are upregulated in tumour tissues of patients with HCC and, thus, may be associated with the pathogenesis of hepatocellular carcinoma.

Hepatitis C virus protein interaction network for HCV clearance and association of DAA to HCC occurrence via data mining approach: A systematic review and critical analysis

HCV has been associated with a pro-inflammatory state, which predisposes to hepatocellular carcinoma (HCC). However, the different molecular mechanisms underlying the effect of HCV infection on HCC progression remain unclear. Although HCV infection illustrates the potential role of host genetics in the outcome of infectious diseases, there is no clear overview of some single nucleotide polymorphisms (SNPs) influencing spontaneous or treatment-induced HCV eradication. We studied the possible role of HCV infection in the processes of HCC initiation and performed a systematic analysis using data mining approaches to identify host polymorphisms associated with treatment response and HCC development using topological analysis of protein-proteins interactions (PPI) networks. On the basis of our analysis performed, we identified key hub proteins related to HCV-treatment response infection and to HCC development. Host genetic polymorphisms, such as inosine triphosphatase (ITPA), interferon, lambda 3 (IFNL3), Q5 interferon, lambda 4 (IFNL4), toll-like receptors (TLRs) and interferon-stimulated gene 15 (ISG-15), were identified as key genes for treatment prediction and HCC evolution. By comparing unique genes for HCV-treatment response and genes particular to HCV-HCC development, we found a common PPI network that may participate in more extensive signalling processes during anti-HCV treatment, which can play important roles in modulating the immune response to the occurrence of HCC. Data mining is an effective tool for identifying potential regulatory pathways involved in treatment response and HCC development. Our study may contribute to a better understanding of HCV immunopathogenesis and highlights the complex role of host genetics in HCV clearance.

Comparison of ISG15, IL28B and USP18 mRNA levels in peripheral blood mononuclear cells of chronic hepatitis B virus infected patients and healthy individuals

AIM

The purpose of this study was to evaluate the expression level of Interferon-stimulated Gene 15 (ISG15), Interleukin28B (IL28B) or IFN-lambda-3 and Ubiquitin specific peptidase 18 (USP18) genes in Peripheral Blood Mononuclear Cells (PBMCs) of patients with chronic active and inactive hepatitis B in comparison with healthy individuals.

BACKGROUND

Despite the presence of the vaccine for hepatitis B virus (HBV), it remains a public health challenge. The effort to uncover the immune genes attributed to infection outcome is going through.

METHODS

This Cross-sectional study was conducted on hepatitis B infected patients that were admitted to the Clinic of Liver diseases, Shiraz, January-November 2016. Patients were divided into two groups including active and inactive chronic regarding relevant World Gastroenterology Organization Global Guideline. They were mono-infected with HBV, and HCV or HIV co-infection was excluded from the study. Gene expression analysis was performed on fresh PBMCs samples with the help of Real-time PCR method.

RESULTS

Interleukin 28B gene expression showed no statistically significant difference between the three studied groups (P>0.05). The expression level of ISG15 was significantly higher in the healthy control group compared to active (P= 0.0068) and inactive chronic subjects (P<0.0001). Similarly, USP18 expression level in the control group was also significantly higher compared to the active (P= 0.0228) and inactive chronic patients (P=0. 0226).

CONCLUSION

The results of this study showed that the expression level of ISG15 and USP18 but not IL28B were higher in healthy individuals than in those infected with HBV. This difference expression may highlight the role of ISG15 and USP18 in the immune-related mechanism of HBV infection.

Serum NOX2 as a new biomarker candidate for HBV-related disorders

Growing evidence supports the notion that serum NAPDH oxidase 2 (NOX2) is an important regulator that contributes to the initiation and progression of various types of diseases. However, so far, it remains elusive about the relationship between levels of serum NOX2 and HBV-related diseases. The overall purpose of the study is to get a better insight into whether or not serum NOX2 is involved in HBV-related disorders. Serum levels of NOX2, from 105 patients with chronic hepatitis B, 58 patients with HBV-related cirrhosis, 48 patients with HBV-related hepatocellular carcinoma and 104 healthy individuals, were measured with sandwich ELISA kits that we developed. In this study, we found that NOX2 values were significantly higher in patients compared to healthy control (P < 0.01) and that the levels of serum NOX2 were significantly correlated with the serum levels of superoxide dismutase (SOD), interleukin-6 (IL-6), interferon-stimulated gene 15 (ISG15), alkaline phosphatase (ALP) and gamma glutamyl transpeptidase (GGT) in chronic hepatitis B, cirrhosis and hepatocellular carcinoma patients. Interestingly, we found that a significant positive correlation between NOX2 and HBV viral load only in patients with chronic hepatitis B and cirrhosis. Therefore, Serum NOX2 levels maybe an important indicator of the pathogenesis of progression of HBV-related disorders.

Interferon-stimulated gene 20 kDa protein serum levels and clinical outcome of hepatitis B virus-related liver diseases

Interferon-stimulated gene 20 kDa protein (ISG20) with 3' to 5' exonuclease activity mainly targeting single-stranded RNA plays an important role in immune responses against various infectious pathogens, including hepatitis viruses. ISG20 levels were measured by ELISA assays in sera of 339 hepatitis B-virus (HBV) infected patients and 71 healthy individuals and were correlated with clinical and laboratory parameters. ISG20 mRNA was quantified by qRT-PCR in 30 pairs of hepatocellular carcinoma (HCC) tumour and adjacent non-tumour liver tissues. ISG20 levels were significantly elevated in HBV patients compared to healthy controls (P<0.0001). In the patient group, varying ISG20 levels were associated with different forms of HBV-related liver diseases. ISG20 levels were higher in patients with HCC compared to those without HCC (P<0.0001), and increased according to the stages of HCC (P<0.0001). ISG20 mRNA expression was up-regulated in tumour tissues compared to the expression in adjacent non-tumour tissues (P=0.017). Importantly, ISG20 levels were strongly correlated with the levels of AST, ALT, total and direct bilirubin among HCC patients (Pearson's r = 0.43, 0.35, 0.34, 0.3; P<0.0001, respectively). Although differences between liver cirrhosis (LC) and non-LC patients were not observed, ISG20 levels were elevated according to the progression of cirrhosis in patients with LC plus HCC (P=0.005). In conclusions, ISG20 levels are induced by HBV infection and significantly associated with progression and clinical outcome of HBV-related liver diseases, especially in patients with HCC. ISG20 might be a potential indicator for liver injury and the clinical outcome in HBV-related HCC.

Genetic variants of interferon regulatory factor 5 associated with chronic hepatitis B infection

AIM

To investigate possible effects of IRF5 polymorphisms in the 3' UTR region of the IFR5 locus on susceptibility to hepatitis B virus (HBV) infection and progression of liver diseases among clinically classified Vietnamese patients.

METHODS

Four IFR5 SNPs (rs13242262A/T, rs77416878C/T, rs10488630A/G, and rs2280714T/C) were genotyped in clinically classified HBV patients [chronic hepatitis B (CHB). n = 99; liver cirrhosis (LC), n = 131; hepatocellular carcinoma (HCC), n = 149] and in 242 healthy controls by direct sequencing and TaqMan real-time PCR assays.

RESULTS

Comparing patients and controls, no significant association was observed for the four IFR5 variants. However, the alleles rs13242262T and rs10488630G contributed to an increased risk of liver cirrhosis (LC vs CHB: OR = 1.5, 95%CI: 1.1-2.3, adjusted P = 0.04; LC vs CHB: OR = 1.7, 95%CI: 1.1-2.6, adjusted P = 0.019). Haplotype IRF5*TCGT constructed from 4 SNPs was observed frequently in LC compared to CHB patients (OR = 2.1, 95%CI: 1.2-3.3, adjusted P = 0.008). Haplotype IRF5*TCAT occurred rather among CHB patients than in the other HBV patient groups (LC vs CHB: OR = 0.4, 95%CI: 0.2-0.8, adjusted P = 0.03; HCC vs CHB: OR = 0.3, 95%CI: 0.15-0.7, adjusted P = 0.003). The IRF5*TCAT haplotype was also associated with increased levels of ALT, AST and bilirubin.

CONCLUSION

Our study shows that IFR5 variants may contribute as a host factor in determining the pathogenesis in chronic HBV infections.