Mx1, OAS1 and OAS2 polymorphisms are associated with the severity of liver disease in HIV/HCV-coinfected patients: A cross-sectional study

Differential transcriptome response following infection of porcine ileal enteroids with species A and C rotaviruses

BACKGROUND

Rotavirus C (RVC) is the major causative agent of acute gastroenteritis in suckling piglets, while most RVAs mostly affect weaned animals. Besides, while most RVA strains can be propagated in MA-104 and other continuous cell lines, attempts to isolate and culture RVC strains remain largely unsuccessful. The host factors associated with these unique RVC characteristics remain unknown.

METHODS

In this study, we have comparatively evaluated transcriptome responses of porcine ileal enteroids infected with RVC G1P[1] and two RVA strains (G9P[13] and G5P[7]) with a focus on innate immunity and virus-host receptor interactions.

RESULTS

The analysis of differentially expressed genes regulating antiviral immune response indicated that in contrast to RVA, RVC infection resulted in robust upregulation of expression of the genes encoding pattern recognition receptors including RIG1-like receptors and melanoma differentiation-associated gene-5. RVC infection was associated with a prominent upregulation of the most of glycosyltransferase-encoding genes except for the sialyltransferase-encoding genes which were downregulated similar to the effects observed for G9P[13].

CONCLUSIONS

Our results provide novel data highlighting the unique aspects of the RVC-associated host cellular signalling and suggest that increased upregulation of the key antiviral factors maybe one of the mechanisms responsible for RVC age-specific characteristics and its inability to replicate in most cell cultures.

RNA-Seq and Immune Repertoire Analysis of Normal and Hepatocellular Carcinoma Relapse After Liver Transplantation

Background

Hepatocellular carcinoma (HCC) relapse is the main reason for the poor prognosis of HCC after Liver transplantation (LT). This study aimed to explore the molecular mechanisms and immune repertoire profiles of HCC relapse.

Material and Methods

RNA-seq of blood samples from patients with normal (n=12) and HCC relapse (n=6) after LT was performed to identify differentially expressed genes (DEGs) and key signalling pathways. The DEGs and immune genes were further analyzed by bioinformatics. TRUST4 was used to analyze the differences in the immune repertoire between the two groups. Another 11 blood samples from patients with HCC who had received LT were collected for RT-qPCR verification of key genes.

Results

A total of 131 upregulated and 157 downregulated genes were identified using RNA-seq, and GO enrichment analysis revealed that the top 15 pathways were immune-related. The PPI network identified 10 key genes. Immune infiltration analysis revealed a significant difference in the five immune cell types between the two groups. A total of 83 intersecting genes were obtained by intersecting DEGs and immune genes. 6 key genes, including MX1, ISG15, OAS1, PRF1, SPP1, and THBS1 were obtained according to the intersection of DEGs, PPI network top 10 genes and immune intersecting genes. Immune repertoire analysis showed that the usage frequency of variable (V) and joining (J) genes in the normal group was higher than that in the relapse group. RT-qPCR validation showed that the expression levels of key genes were consistent with the RNA-seq results.

Conclusion

Our study identified key pathways and genes that could help determine whether transplant recipients are more prone to HCC relapse. Immune repertoire analysis revealed a difference in the usage frequency of VJ genes between the normal and relapse groups, providing a research direction for immunotherapy in patients with HCC relapse after liver transplantation.

Genetic Ethnic Differences in Human 2'-5'-Oligoadenylate Synthetase and Disease Associations: A Systematic Review

Recently, several studies have highlighted a skewed prevalence of infectious diseases within the African continent. Furthermore, a growing number of studies have demonstrated unique genetic variants found within the African genome are one of the contributing factors to the disease severity of infectious diseases within Africa. Understanding the host genetic mechanisms that offer protection against infectious diseases provides an opportunity to develop unique therapeutic interventions. Over the past two decades, several studies have linked the 2'-5'-oligoadenylate synthetase (OAS) family with a range of infectious diseases. More recently, the OAS-1 gene has also been associated with disease severity caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which led to a global pandemic. The OAS family serves as an antiviral factor through the interaction with Ribonuclease-Latent (RNase-L). This review explores the genetic variants observed within the OAS genes and the associations with various viral infections and how previously reported ethnic-specific polymorphisms drive clinical significance. This review provides an overview of OAS genetic association studies with a particular focus on viral diseases affecting individuals of African descent.

Polymorphisms of the MxA and MxB genes are associated with biochemical indices and viral subtypes in Yunnan HCV patients

Introduction

Hepatitis C virus (HCV) infection was the primary reason causing critical hepatic Q7 diseases. Although direct-acting antiviral agents (DAA) were widely used in clinics, anti-drug mutation, the outcome of patients with different viral subtypes, and recurrence suggested that HCV pathogenic mechanism should be studied further. HCV infection, replication, and outcome were influenced by the IFNL4 and itsdownstream genes (MxA and MxB). However, whether genetic polymorphisms of these genes played necessary roles required verification in the Yunnan population.

Methods and Results

After analyzing the genotypes and allele frequencies of seven single nucleotide polymorphisms (SNP), we found the association between the genotype and allele frequencies of rs11322783 in the IFNL4 gene and HCV infection in Yunnan population. Furthermore, the genetic polymorphisms of the MxA and MxB genescould influence liver function of HCV patients. The indirect bilirubin (IBIL) and albumin (ALB) levels showed significant differences among HCV patients, who carried various genotypes. The IBIL levels were associated with genotypes of rs17000900 (P= 0.025) and rs2071430 (P= 0.037) in the MxA gene, and ALB levels were associated with genotypes of rs2838029 (P= 0.010) in the MxB gene. Similarly, the genotypes of SNPs also showed significant difference in patients infected with subtype 3a (P=0.035) and 2a (P=0.034). However, no association was identified between expression level and SNPs of the MxA and MxB genes. Furthermore, HCV subtype 3b was found to be the predominantly epidemic strain in Yunnan Province.

Conclusion

In conclusion, the association between biochemical indices/HCV subtypes and SNPs in the MxA and MxB genes was identified in Yunnan HCV population.

Molecular Mechanisms of ZIKV-Induced Teratogenesis: A Systematic Review of Studies in Animal Models

Zika virus (ZIKV) is a teratogen that causes congenital anomalies, being linked to microcephaly in children exposed during pregnancy. Animal studies have been conducted to investigate the molecular mechanisms related to ZIKV teratogenesis. Although animal models can mimic the effects of ZIKV in human embryo development, few in vivo studies have addressed molecular changes following ZIKV infection in embryos. Moreover, few literature reviews have been conducted with these studies. The aim of this systematic review is to evaluate the molecular mechanisms of ZIKV teratogenesis determined from studies in animal models. PubMed/MEDLINE, EMBASE, Web of Science, and Scopus as well as grey literature were searched for studies that evaluated molecular alterations related to ZIKV teratogenesis which occurred during embryonic development. Nine studies were included: six with mice, one with mice and guinea pigs, one with pigs and one with chickens. In general, studies presented an unclear or high risk of bias for methodological criteria. Most of studies reported embryos exposed to ZIKV presenting microcephaly, reduced cortex thickness, and growth restriction. Different techniques were used to evaluated molecular changes in the animals following ZIKV infection: RNA sequencing, RT-qPCR, and in situ hybridization. It was found that common pathways are changed in most studies, being pathways related to immune response upregulated and those involved to neurodevelopment downregulated.

Identification and validation of key biomarkers for the early diagnosis of diabetic kidney disease

Background: Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. This study explored the core genes and pathways associated with DKD to identify potential diagnostic and therapeutic targets.

Methods: We downloaded microarray datasets GSE96804 and GSE104948 from the Gene Expression Omnibus (GEO) database. The dataset includes a total of 53 DKD samples and 41 normal samples. Differentially expressed genes (DEGs) were identified using the R package “limma”. The Metascape database was subjected to Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses to identify the pathway and functional annotations of DEGs. A WGCAN network was constructed, the hub genes in the turquoise module were screened, and the core genes were selected using LASSO regression to construct a diagnostic model that was then validated in an independent dataset. The core genes were verified by in vitro and in vivo experiments.

Results: A total of 430 DEGs were identified in the GSE96804 dataset, including 285 upregulated and 145 downregulated DEGs. WGCNA screened out 128 modeled candidate gene sets. A total of eight genes characteristic of DKD were identified by LASSO regression to build a prediction model. The results showed accuracies of 99.15% in the training set (GSE96804) and 94.44% and 100%, respectively, in the test (GSE104948-GPL22945 and GSE104948-GPL24120). Three core genes (OAS1, SECTM1, and SNW1) with high connectivity were selected among the modeled genes. In vitro and in vivo experiments confirmed the upregulation of these genes.

Conclusion: Bioinformatics analysis combined with experimental validation identified three novel DKD-specific genes. These findings may advance our understanding of the molecular basis of DKD and provide potential therapeutic targets for its clinical management.

Galectin-9 and Interferon-Gamma Are Released by Natural Killer Cells upon Activation with Interferon-Alpha and Orchestrate the Suppression of Hepatitis C Virus Infection

Natural killer (NK) cells mount an immune response against hepatitis C virus (HCV) infection and can be activated by several cytokines, including interleukin-2 (IL-2), IL-15, and interferon-alpha (IFN-α). By exploiting the Huh7.5 hepatoma cell line infected with the HCV JFH1 genome, we provide novel insights into the antiviral effector functions of human primary NK cells after cytokine stimulation. NK cells activated with IFN-α (IFNα-NKs) had enhanced contact-dependent and -independent responses as compared with NK cells activated with IL-2/IL-15 (IL2/IL15-NKs) and could inhibit HCV replication both in vitro and in vivo. Importantly, IFN-α, but not IL-2/IL-15, protected NK cells from the functional inhibition exerted by HCV. By performing flow cytometry, multiplex cytokine profiling, and mass-spectrometry-based proteomics, we discovered that IFNα-NKs secreted high levels of galectin-9 and interferon-gamma (IFN-γ), and by conducting neutralization assays, we confirmed the major role of these molecules in HCV suppression. We speculated that galectin-9 might act extracellularly to inhibit HCV binding to host cells and downstream infection. In silico approaches predicted the binding of HCV envelope protein E2 to galectin-9 carbohydrate-recognition domains, and co-immunoprecipitation assays confirmed physical interaction. IFN-γ, on the other hand, triggered the intracellular expressions of two antiviral gate-keepers in target cells, namely, myxovirus-1 (MX1) and interferon-induced protein with tetratricopeptide repeats 1 (IFIT1). Collectively, our data add more complexity to the antiviral innate response mediated by NK cells and highlight galectin-9 as a key molecule that might be exploited to neutralize productive viral infection.

Japanese Encephalitis Virus infection increases USP42 to stabilize TRIM21 and OAS1 for neuroinflammatory and anti-viral response in human microglia

Japanese Encephalitis Virus (JEV), a member virus of Flaviviridae family causes Japanese encephalitis (JE). JE is a mosquito-borne disease, spread mainly by Culex spp. During JE, dysregulated inflammatory responses play a central role in neuronal death and damage leading to Neuroinflammation. In this study, we show that JEV infection in human microglial cells (CHME3) reduces the cellular miR-590-3p levels. miR-590-3p could directly target the expression levels of USP42 (Ubiquitin Specific Peptidase 42) resulting in increased cellular levels of USP42 upon JEV infection. Our results suggest that USP42 stabilizes cellular TRIM21 via deubiquitinating them. We also established through various in vitro and in vivo experiments that increased USP42 can maintain a higher cellular level of both TRIM21 as well as OAS1. This study also suggests that TRIM21, independently of its RING domain, can increase USP42 level in a positive feedback loop and induces the cellular OAS1 levels in human microglial cells.

Integrated analysis of differentially expressed genes, differentially methylated genes, and natural compounds in hepatitis C virus-induced cirrhosis

Objective

To identify key genes in hepatitis C virus (HCV)-induced cirrhosis and to predict effective drugs for its treatment.

Methods

Three datasets were used to screen for differentially expressed genes (DEGs) and differentially methylated genes (DMGs) in HCV-induced cirrhosis. DEGs were subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses using the clusterProfiler R package. Their respective protein–protein interaction (PPI) networks were constructed using Cytoscape. Cross analysis of DEGs and DMGs was performed to identify the genetic landscape of HCV-induced cirrhosis, and five genes were validated by receiver operating characteristic curve analysis. Molecular autodocking between ISG15 and natural products was performed using AutoDock Tool 1.5.6.

Results

A total of 357 DEGs and 8,830 DMGs were identified. DEG functional analysis identified several pathways involved in the pathogenesis of HCV-induced cirrhosis. Cross analysis of DEGs and DMGs identified 212 genes, and PPI network analysis identified 25 hub genes. Finally, five genes including ISG15 were identified and confirmed in dataset GSE36411. Artesunate and betulinic acid were shown to have a strong binding affinity to ISG15.

Conclusion

Our study provides novel insights into the mechanisms of HCV-induced cirrhosis which could lead to the identification of new therapeutics.

Potential Molecular Mechanisms and Remdesivir Treatment for Acute Respiratory Syndrome Corona Virus 2 Infection/COVID 19 Through RNA Sequencing and Bioinformatics Analysis

Introduction:

Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) infections (COVID 19) is a progressive viral infection that has been investigated extensively. However, genetic features and molecular pathogenesis underlying remdesivir treatment for SARS-CoV-2 infection remain unclear. Here, we used bioinformatics to investigate the candidate genes associated in the molecular pathogenesis of remdesivir-treated SARS-CoV-2-infected patients.

Methods:

Expression profiling by high-throughput sequencing dataset (GSE149273) was downloaded from the Gene Expression Omnibus, and the differentially expressed genes (DEGs) in remdesivir-treated SARS-CoV-2 infection samples and nontreated SARS-CoV-2 infection samples with an adjusted P value of <.05 and a |log fold change| > 1.3 were first identified by limma in R software package. Next, pathway and gene ontology (GO) enrichment analysis of these DEGs was performed. Then, the hub genes were identified by the NetworkAnalyzer plugin and the other bioinformatics approaches including protein-protein interaction network analysis, module analysis, target gene—miRNA regulatory network, and target gene—TF regulatory network. Finally, a receiver-operating characteristic analysis was performed for diagnostic values associated with hub genes.

Results:

A total of 909 DEGs were identified, including 453 upregulated genes and 457 downregulated genes. As for the pathway and GO enrichment analysis, the upregulated genes were mainly linked with influenza A and defense response, whereas downregulated genes were mainly linked with drug metabolism—cytochrome P450 and reproductive process. In addition, 10 hub genes (VCAM1, IKBKE, STAT1, IL7R, ISG15, E2F1, ZBTB16, TFAP4, ATP6V1B1, and APBB1) were identified. Receiver-operating characteristic analysis showed that hub genes (CIITA, HSPA6, MYD88, SOCS3, TNFRSF10A, ADH1A, CACNA2D2, DUSP9, FMO5, and PDE1A) had good diagnostic values.

Conclusion:

This study provided insights into the molecular mechanism of remdesivir-treated SARS-CoV-2 infection that might be useful in further investigations.

Bioinformatics Analysis of Allele Frequencies and Expression Patterns of ACE2, TMPRSS2 and FURIN in Different Populations and Susceptibility to SARS-CoV-2

The virus responsible for the COVID-19 global health crisis, SARS-CoV-2, has been shown to utilize the ACE2 protein as an entry point to its target cells. The virus has been shown to rely on the actions of TMPRSS2 (a serine protease), as well as FURIN (a peptidase), for the critical priming of its spike protein. It has been postulated that variations in the sequence and expression of SARS-CoV-2's receptor (ACE2) and the two priming proteases (TMPRSS2 and FURIN) may be critical in contributing to SARS-CoV-2 infectivity. This study aims to examine the different expression levels of FURIN in various tissues and age ranges in light of ACE2 and TMPRSS2 expression levels using the LungMAP database. Furthermore, we retrieved expression quantitative trait loci (eQTLs) of the three genes and their annotation. We analyzed the frequency of the retrieved variants in data from various populations and compared it to the Egyptian population. We highlight FURIN's potential interplay with the immune response to SARS-CoV-2 and showcase a myriad of variants of the three genes that are differentially expressed across populations. Our findings provide insights into potential genetic factors that impact SARS-CoV-2 infectivity in different populations and shed light on the varying expression patterns of FURIN.

Plasmacytoid dendritic cells respond to Epstein-Barr virus infection with a distinct type I interferon subtype profile

Infectious mononucleosis, caused by infection with the human gamma-herpesvirus Epstein-Barr virus (EBV), manifests with one of the strongest CD8⁺ T-cell responses described in humans. The resulting T-cell memory response controls EBV infection asymptomatically in the vast majority of persistently infected individuals. Whether and how dendritic cells (DCs) contribute to the priming of this near-perfect immune control remains unclear. Here we show that of all the human DC subsets, plasmacytoid DCs (pDCs) play a central role in the detection of EBV infection in vitro and in mice with reconstituted human immune system components. pDCs respond to EBV by producing the interferon (IFN) subtypes α1, α2, α5, α7, α14, and α17. However, the virus curtails this type I IFN production with its latent EBV gene products EBNA3A and EBNA3C. The induced type I IFNs inhibit EBV entry and the proliferation of latently EBV-transformed B cells but do not influence lytic reactivation of the virus in vitro. In vivo, exogenous IFN-α14 and IFN-α17, as well as pDC expansion, delay EBV infection and the resulting CD8⁺ T-cell expansion, but pDC depletion does not significantly influence EBV infection. Thus, consistent with the observation that primary immunodeficiencies compromising type I IFN responses affect only alpha- and beta-herpesvirus infections, we found that EBV elicits pDC responses that transiently suppress viral replication and attenuate CD8⁺ T-cell expansion but are not required to control primary infection.

Mapping Viral Susceptibility Loci in Mice

Genetic alleles that contribute to enhanced susceptibility or resistance to viral infections and virally induced diseases have often been first identified in mice before humans due to the significant advantages of the murine system for genetic studies. Herein we review multiple discoveries that have revealed significant insights into virus-host interactions, all made using genetic mapping tools in mice. Factors that have been identified include innate and adaptive immunity genes that contribute to host defense against pathogenic viruses such as herpes viruses, flaviviruses, retroviruses, and coronaviruses. Understanding the genetic mechanisms that affect infectious disease outcomes will aid the development of personalized treatment and preventive strategies for pathogenic infections.

Genetic variants that influence SARS-CoV-2 receptor TMPRSS2 expression among population cohorts from multiple continents

The World Health Organization recently announced that pandemic status has been achieved for coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Exponential increases in patient numbers have been reported around the world, along with proportional increases in the number of COVID-19-related deaths. The SARS-CoV-2 infection rate in a population is expected to be influenced by social practices, availability of vaccines or prophylactics, and the prevalence of susceptibility genes in the population. Previous work revealed that cellular uptake of SARS-CoV-2 requires Angiotensin Converting Enzyme 2 (ACE-2) and a cellular protease. The spike (S) protein on SARS-CoV-2 binds ACE-2, which functions as an entry receptor. Following receptor binding, transmembrane protease serine 2 (encoded by TMPRSS2) primes the S protein to allow cellular uptake. Therefore, individual expression of TMPRSS2 may be a crucial determinant of SARS-CoV-2 infection susceptibility. Here, we utilized multiple large genome databases, including the GTEx portal, SNP nexus, and Ensembl genome project, to identify gene expression profiles for TMPRSS2 and its important expression quantitative trait loci. Our results show that four variants (rs464397, rs469390, rs2070788 and rs383510) affect expression of TMPRSS2 in lung tissue. The allele frequency of each variant was then assessed in regional populations, including African, American, European, and three Asian cohorts (China, Japan and Taiwan). Interestingly, our data shows that TMPRSS2-upregulating variants are at higher frequencies in European and American populations than in the Asian populations, which implies that these populations might be relatively susceptible to SARS-CoV-2 infection.

A comprehensive genome-wide profiling comparison between HBV and HCV infected hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, especially in East Asia. Even with the progress in therapy, 5-year survival rates remain unsatisfied. Chronic infection with the hepatitis B virus (HBV) or hepatitis C virus (HCV) has been epidemiologically associated with HCC and is the major etiology in the East Asian population. The detailed mechanism, especially the changes of DNA methylation and gene expression between the two types of virus-related HCC, and their contributions to the HCC development, metastasis, and recurrence remain largely unknown.

METHODS

In this integrated analysis, we characterized genome-scale profiles of HBV and HCV infected HCC by comparing their gene expression pattern, methylation profiles, and copy number variations from the publicly accessible data of The Cancer Genome Atlas Program (TCGA).

RESULTS

The HLA-A, STAT1, and OAS2 genes were highly enriched and up-regulated discovered in the HCV-infected HCC. Hypomethylation but not copy number variations might be the major factor for the up-regulation of these immune-related genes in HCV-infected HCC.

CONCLUSIONS

The results indicated the different epigenetic changes of HBV/HCV related hepatocarcinogenesis. The top up-regulated genes in HCV group were significantly clustered in the immune-related and defense response pathways. These findings will help us to understand the pathogenesis of HBV/HCV associated hepatocellular carcinoma.

Human immunodeficiency virus and hepatotropic viruses co-morbidities as the inducers of liver injury progression

Hepatotropic viruses induced hepatitis progresses much faster and causes more liver- related health problems in people co-infected with human immunodeficiency virus (HIV). Although treatment with antiretroviral therapy has extended the life expectancy of people with HIV, liver disease induced by hepatitis B virus (HBV) and hepatitis C virus (HCV) causes significant numbers of non-acquired immune deficiency syndrome (AIDS)-related deaths in co-infected patients. In recent years, new insights into the mechanisms of accelerated fibrosis and liver disease progression in HIV/HCV and HIV/HBV co-infections have been reported. In this paper, we review recent studies examining the natural history and pathogenesis of liver disease in HIV-HCV/HBV co-infection in the era of direct acting antivirals (DAA) and antiretroviral therapy (ART). We also review the novel therapeutics for management of HIV/HCV and HIV/HBV co-infected individuals.

Integrative Bioinformatics Analysis Provides Insight into the Molecular Mechanisms of Chronic Kidney Disease

BACKGROUND/AIMS

Chronic kidney disease (CKD) is a worldwide public health problem. Regardless of the underlying primary disease, CKD tends to progress to end-stage kidney disease, resulting in unsatisfactory and costly treatment. Its common pathogenesis, however, remains unclear. The aim of this study was to provide an unbiased catalog of common gene-expression changes of CKD and reveal the underlying molecular mechanism using an integrative bioinformatics approach.

METHODS

We systematically collected over 250 Affymetrix microarray datasets from the glomerular and tubulointerstitial compartments of healthy renal tissues and those with various types of established CKD (diabetic kidney disease, hypertensive nephropathy, and glomerular nephropathy). Then, using stringent bioinformatics analysis, shared differentially expressed genes (DEGs) of CKD were obtained. These shared DEGs were further analyzed by the gene ontology (GO) and pathway enrichment analysis. Finally, the protein-protein interaction networks(PINs) were constructed to further refine our results.

RESULTS

Our analysis identified 176 and 50 shared DEGs in diseased glomeruli and tubules, respectively, including many transcripts that have not been previously reported to be involved in kidney disease. Enrichment analysis also showed that the glomerular and tubulointerstitial compartments underwent a wide range of unique pathological changes during chronic injury. As revealed by the GO enrichment analysis, shared DEGs in glomeruli were significantly enriched in exosomes. By constructing PINs, we identified several hub genes (e.g. OAS1, JUN, and FOS) and clusters that might play key roles in regulating the development of CKD.

CONCLUSION

Our study not only further reveals the unifying molecular mechanism of CKD pathogenesis but also provides a valuable resource of potential biomarkers and therapeutic targets.

Consequence of HIV and HCV co-infection on host immune response, persistence and current treatment options

Hepatitis C virus (HCV) is a common opportunistic pathogen especially among Human immunodeficiency virus (HIV) infected patients. Due to incongruous studies, the pathological effect of HCV on HIV induced disease are still not fully understood. While some studies have showed no effect of HCV on HIV infection, others reported a defined role of HCV in aggravating the rates of AIDS-related illnesses and mortality. The explanation of such variances may be due to the host immune response, viral genotypes, sub-type and quasi-species distribution. The factors that complicate the management of HIV/HCV patients are: (1) reduced HCV antibody production, (2) drug interactions, (3) liver disease and (4) different epidemiologic characteristics. However, it is abundantly clear that the morbidity and mortality caused by HCV have increased since the introduction of highly active antiretroviral therapy (HAART) against HIV. In this review, the consequence of HIV/HCV co-infection on host immune response, viral replication, disease progression, mortality and morbidity, viral load, persistence and current treatment options have been discussed. Based on the clinical studies, it is necessary to evaluate the effect of HCV therapy on HIV progression and to provide a fully active HCV treatment for patients receiving HIV treatment. In conclusion, it is recommended to provide fully active HAART therapy in combination with a known HCV therapy.

Low-Grade Dysplastic Nodules Revealed as the Tipping Point during Multistep Hepatocarcinogenesis by Dynamic Network Biomarkers

Hepatocellular carcinoma (HCC) is a complex disease with a multi-step carcinogenic process from preneoplastic lesions, including cirrhosis, low-grade dysplastic nodules (LGDNs), and high-grade dysplastic nodules (HGDNs) to HCC. There is only an elemental understanding of its molecular pathogenesis, for which a key problem is to identify when and how the critical transition happens during the HCC initiation period at a molecular level. In this work, for the first time, we revealed that LGDNs is the tipping point (i.e., pre-HCC state rather than HCC state) of hepatocarcinogenesis based on a series of gene expression profiles by a new mathematical model termed dynamic network biomarkers (DNB)—a group of dominant genes or molecules for the transition. Different from the conventional biomarkers based on the differential expressions of the observed genes (or molecules) for diagnosing a disease state, the DNB model exploits collective fluctuations and correlations of the observed genes, thereby predicting the imminent disease state or diagnosing the critical state. Our results show that DNB composed of 59 genes signals the tipping point of HCC (i.e., LGDNs). On the other hand, there are a large number of differentially expressed genes between cirrhosis and HGDNs, which highlighted the stark differences or drastic changes before and after the tipping point or LGDNs, implying the 59 DNB members serving as the early-warning signals of the upcoming drastic deterioration for HCC. We further identified the biological pathways responsible for this transition, such as the type I interferon signaling pathway, Janus kinase–signal transducers and activators of transcription (JAK–STAT) signaling pathway, transforming growth factor (TGF)-β signaling pathway, retinoic acid-inducible gene I (RIG-I)-like receptor signaling pathway, cell adhesion molecules, and cell cycle. In particular, pathways related to immune system reactions and cell adhesion were downregulated, and pathways related to cell growth and death were upregulated. Furthermore, DNB was validated as an effective predictor of prognosis for HCV-induced HCC patients by survival analysis on independent data, suggesting a potential clinical application of DNB. This work provides biological insights into the dynamic regulations of the critical transitions during multistep hepatocarcinogenesis.

ISG15 Modulates Type I Interferon Signaling and the Antiviral Response during Hepatitis E Virus Replication

Hepatitis E virus (HEV), a single-stranded positive-sense RNA virus, generally causes self-limiting acute viral hepatitis, although chronic HEV infection has recently become a significant clinical problem in immunocompromised individuals, especially in solid-organ transplant recipients. Innate immunity, via the type I interferon (IFN) response, plays an important role during the initial stages of a viral infection. IFN-stimulated gene 15 (ISG15), an IFN-induced ubiquitin-like protein, is known to have an immunomodulatory role and can have a direct antiviral effect on a wide spectrum of virus families. In the present study, we investigated the antiviral effect as well as the potential immunomodulatory role of ISG15 during HEV replication. The results revealed that HEV induced high levels of ISG15 production both in vitro (Huh7-S10-3 liver cells) and in vivo (liver tissues from HEV-infected pigs); however, ISG15 is not required for virus replication. We also demonstrated that ISG15 silencing potentiates enhanced type I IFN-mediated signaling, resulting in an increase in the type I IFN-mediated antiviral effect during HEV replication. This observed enhanced type I IFN signaling correlated with an increase in IFN-stimulated gene expression levels during HEV replication. Furthermore, we showed that PKR and OAS1 played important roles in the ISG15-mediated type I IFN sensitivity of HEV. Taken together, the results from this study suggest that ISG15 plays an important immunomodulatory role and regulates HEV sensitivity to exogenous type I IFN.IMPORTANCE Hepatitis E virus (HEV) infection typically causes self-limiting acute viral hepatitis. However, chronic HEV infection has recently become a significant clinical problem in immunocompromised patients. Pegylated interferon (IFN) has been used to treat chronic HEV infection in solid-organ transplant patients with some success. However, the mechanism behind the type I IFN-mediated antiviral effect against HEV remains unclear. This report demonstrates that ISG15 induced by HEV replication in Huh7-S10-3 human liver cells plays an immunomodulatory role by negatively regulating type I IFN signaling and, thus, HEV sensitivity to type I IFN. Our results also show that PKR and OAS1 play important roles in the ISG15-mediated type I IFN sensitivity of HEV.