microRNA-122 abundance in hepatocellular carcinoma and non-tumor liver tissue from Japanese patients with persistent HCV versus HBV infection

From discovery to treatment: tracing the path of hepatitis E virus

The hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide. HEV is classified into eight genotypes, labeled HEV-1 through HEV-8. Genotypes 1 and 2 exclusively infect humans, while genotypes 3, 4, and 7 can infect both humans and animals. In contrast, genotypes 5, 6, and 8 are restricted to infecting animals. While most individuals with a strong immune system experience a self-limiting infection, those who are immunosuppressed may develop chronic hepatitis. Pregnant women are particularly vulnerable to severe illness and mortality due to HEV infection. In addition to liver-related complications, HEV can also cause extrahepatic manifestations, including neurological disorders. The immune response is vital in determining the outcome of HEV infection. Deficiencies in T cells, NK cells, and antibody responses are linked to poor prognosis. Interestingly, HEV itself contains microRNAs that regulate its replication and modify the host's antiviral response. Diagnosis of HEV infection involves the detection of HEV RNA and anti-HEV IgM/IgG antibodies. Supportive care is the mainstay of treatment for acute infection, while chronic HEV infection may be cleared with the use of ribavirin and pegylated interferon. Prevention remains the best approach against HEV, focusing on sanitation infrastructure improvements and vaccination, with one vaccine already licensed in China. This comprehensive review provides insights into the spread, genotypes, prevalence, and clinical effects of HEV. Furthermore, it emphasizes the need for further research and attention to HEV, particularly in cases of acute hepatitis, especially among solid-organ transplant recipients.

An In-Depth Approach to the Associations between MicroRNAs and Viral Load in Patients with Chronic Hepatitis B-A Systematic Review and Meta-Analysis

Scientists study the molecular activities of the hepatitis B virus (HBV). However, in vivo experiments are scarce. Some microRNAs are HBV-related, but their exact mechanisms are unknown. Our study provides an up-to-date view of the associations between microRNAs and HBV-DNA levels in chronically infected individuals. We conducted this large-scale research on five databases according to PRISMA guidance. Joanna Briggs Institute tools and Newcastle Ottawa Quality Assessment scores helped with quality evaluations. R 4.2.2 performed statistical computations for the meta-analysis. DIANA-microT 2023 and g:Profiler enriched the predictions of liver genes associated with miR-122 and miR-192-5p. From the 1313 records, we eliminated those irrelevant to our theme, non-article methodologies, non-English entries, and duplicates. We assessed associations between microRNAs and HBV-DNA levels. Overall, the pooled correlations favoured the general idea of the connection between non-coding molecules and viremia levels. MiR-122 and miR-192-5p were the most researched microRNAs, significantly associated with HBV-DNA levels. The connections between miR-122, miR-192-5p, let-7, miR-215, miR-320, and viral loads need further in vivo assessment. To conclude, this study evaluates systematically, for the first time, the correlations between non-coding molecules and viremia levels in patients. Our meta-analysis emphasizes potentially important pathways toward new inhibitors of the viral replication cycle.

MicroRNA-29a and MicroRNA-124 as novel biomarkers for hepatocellular carcinoma

BACKGROUND

Numerous microRNAs (miRNAs) have been observed to be abnormally expressed in cancer. Therefore, miRNA signatures could be potential noninvasive diagnostic and prognostic biomarkers for hepatocellular carcinoma (HCC).

AIMS

To correlate miRNA-29a and miRNA-124 expression levels with the clinical features and survival rates of HCC patients.

METHODS

Serum miRNA expression in 150 samples (50 patients with HCC, 50 patients with liver cirrhosis, and 50 healthy controls) were quantified using real-time qRT-PCR.

RESULTS

The expression levels of serum miRNA-29a were higher and the levels of miRNA-124 were lower in patients with HCC than in patients with liver cirrhosis and controls. ROC curve analysis showed promising accuracy for both miRNAs in distinguishing patients with HCC from those with liver cirrhosis. Levels of miRNA-29a were related to tumor number, size, stage, and outcome, whereas levels of miRNA-124 were related to vascular invasion. The overall survival rate of patients with low miRNA-29a expression was significantly higher than that of patients with high expression. Additionally, the multivariate analysis identified miRNA-29a as an independent prognostic variable.

CONCLUSIONS

The investigated miRNAs showed acceptable accuracy in the diagnosis of HCC; therefore, both could be utilized as diagnostic biomarkers. Additionally, miRNA-29a could be used as a prognostic biomarker.

Circulating MicroRNA-21 and MicroRNA-122 as Prognostic Biomarkers in Hepatocellular Carcinoma Patients Treated with Transarterial Chemoembolization

BACKGROUND

MicroRNAs (miRNAs) have been proposed as biomarkers in hepatocellular carcinoma (HCC). We aim at evaluating miR-21 and miR-122 in HCC patients treated with drug-eluting beads transarterial chemoembolization (DEB-TACE) as prognostic biomarkers and investigating their correlation with hypoxia inducible factor-1α (HIF-1α) serum levels.

METHODS

In this retrospective study, 12 healthy subjects, 28 cirrhotics, and 54 HCC patients (tested before and four weeks after DEB-TACE) were included. Whole blood miR-21 and miR-122 levels were measured by quantitative real time (qRT)-PCR, while serum HIF-1α was assessed by an enzyme-linked immunosorbent assay (ELISA) test.

RESULTS

The highest level of miR-21 was found in cirrhotics, while HCC patients had the highest level of miR-122 (which was even higher in "viral" HCC, p = 0.006). miR-21 ratio (after/before DEB-TACE) and miR-122 below their respective cut-offs identified patients with longer progression-free survival (p = 0.0002 and p = 0.02, respectively). The combined assessment of alpha-fetoprotein and miR-21 ratio, both independent prognostic predictors, identified early progressors among patients with complete or partial radiological response. miR-21 levels positively correlated with HIF-1α before (p = 0.045) and after DEB-TACE (p = 0.035).

CONCLUSIONS

miR-21 ratio and miR-122 are useful prognostic markers after DEB-TACE. miR-21 correlates with HIF-1α and probably has a role in modulating angiogenesis in HCC.

MicroRNA-122 promotes apoptosis of keratinocytes in oral lichen planus through suppressing VDR expression

MicroRNA‐122 (miR‐122) is known to be up‐regulated by inflammation to exert a variety of biological functions in hepatocellular carcinoma (HCC)‐derived human cell lines. Vitamin D receptor (VDR) is reported to regulate excessive oral keratinocytes apoptosis which compromises oral epithelial barrier in oral lichen planus (OLP). Although many studies have suggested that miR‐122 is capable of regulating cell apoptosis, its effects on the development of OLP and VDR expression are still unclear. Herein, we demonstrate that miR‐122 expression is increased in the epithelial layer of OLP. Mechanically, transcription factor nuclear factor‐κB (NF‐κB) selectively binds with κB element in the promoter of miR‐122 to accelerate gene transcription. The up‐regulation of miR‐122 induces cell apoptosis in human oral keratinocytes (HOKs) by targeting VDR mRNA. In VDR knockout oral keratinocytes, miR‐122 fails to improve caspase 3 activity and cleaved caspase 3 and poly(ADP‐ribose) polymerase (PARP) levels. Moreover, VDR overexpression is able to reverse lipopolysaccharide (LPS)‐ or activated CD4+ T cell–induced miR‐122 up‐regulation and ameliorate miR‐122‐stimulated caspase 3 activity. Collectively, our results suggest that miR‐122 promotes oral keratinocytes apoptosis in OLP through decreasing VDR expression.

The Significance of HCV Viral Load in the Incidence of HCC: a Correlation Between Mir-122 and CCL2

BACKGROUND

Hepatocellular carcinoma (HCC) is the fifth most common cancer, the third leading cause of cancer deaths worldwide with over 500,000 people affected. It is a major cause of death in patients with chronic hepatitis C virus (HCV) infection. Overwhelming lines of epidemiological evidence have indicated that persistent infection with HCV is a major risk for the development of HCC. Although a proportion of patients with a chronic hepatitis C virus infection progress to HCC, the peak incidence of HCC associated with HCV infection has not yet occurred.

AIM

This review aimed to assess the impact of hepatitis C viral load on the development of HCC as a correlation between mir-122 and, the key factor in fibrogenesis, CCL2.

CONCLUSION

According to the detailed explanation of the role of mir-122 and CCL2 in HCV and HCC and the evidence of the inverse correlation between them, it may be concluded that HCV may affect mir-122 expression level of the hepatocytes with different patterns depending on the viral genotype. Collectively, HCV viral load alone is not sufficient to predict the HCC development and progression. Besides the quantitative evaluation of the HCV, mir-122 and CCL2 determinations should also be taken into consideration.

Dysregulated microRNAs in Hepatitis B Virus-Related Hepatocellular Carcinoma: Potential as Biomarkers and Therapeutic Targets

MicroRNAs (miRNAs) are non-coding small RNAs that can function as gene regulators and are involved in tumorigenesis. We review the commonly dysregulated miRNAs in liver tumor tissues and plasma/serum of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) patients. The frequently reported up-regulated miRNAs in liver tumor tissues include miR-18a, miR-21, miR-221, miR-222, and miR-224, whereas down-regulated miRNAs include miR-26a, miR-101, miR-122, miR-125b, miR-145, miR-199a, miR-199b, miR-200a, and miR-223. For a subset of these miRNAs (up-regulated miR-222 and miR-224, down-regulated miR-26a and miR-125b), the pattern of dysregulated circulating miRNAs in plasma/serum is mirrored in tumor tissue based on multiple independent studies. Dysregulated miRNAs target oncogenes or tumor suppressor genes involved in hepatocarcinogenesis. Normalization of dysregulated miRNAs by up- or down-regulation has been shown to inhibit HCC cell proliferation or sensitize liver cancer cells to chemotherapeutic treatment. miRNAs hold as yet unrealized potential as biomarkers for early detection of HCC and as precision therapeutic targets, but further studies in diverse populations and across all stages of HCC are needed.

Role of MicroRNA in the Diagnosis and Management of Hepatocellular Carcinoma

INTRODUCTION

Hepatocellular Carcinoma (HCC) is one of the most common malignant tumors in the world and comes third in cancer-induced mortality. The need for improved and more specific diagnostic methods that can detect early-stage disease is immense, as it is amenable to curative modalities, while advanced HCC is associated with low survival rates. microRNA (miRNA) expression is deregulated in HCC and this can be implemented both diagnostically and therapeutically.

OBJECTIVE

To provide a concise review on the role of miRNA in diagnosis, prognosis, and treatment of HCC.

METHODS

We conducted a comprehensive review of the PubMed bibliographic database.

RESULTS

Multiple miRNAs are involved in the pathogenesis of HCC. Measurement of the levels of these miRNAs either in tumor tissue or in the blood constitutes a promising diagnostic, as well as prognostic tool. OncomiRs are miRNAs that promote tumorigenesis, thus inhibiting them by administering antagomiRs is a promising treatment option. Moreover, replacement of the depleted miRNAs is another potential therapeutic approach for HCC. Modification of miRNA levels may also regulate sensitivity to chemotherapeutic agents.

CONCLUSION

miRNA play a pivotal role in HCC pathogenesis and once the underlying mechanisms are elucidated, they will become part of everyday clinical practice against HCC.

Epigenetics of hepatocellular carcinoma

In recent years, large scale genomics and genome-wide studies using comprehensive genomic tools have reshaped our understanding of cancer evolution and heterogeneity. Hepatocellular carcinoma, being one of the most deadly cancers in the world has been well established as a disease of the genome that harbours a multitude of genetic and epigenetic aberrations during the process of liver carcinogenesis. As such, in depth understanding of the cancer epigenetics in cancer specimens and biopsy can be useful in clinical settings for molecular subclassification, prognosis, and prediction of therapeutic responses. In this review, we present a concise discussion on recent progress in the field of liver cancer epigenetics and some of the current works that contribute to the progress of liver cancer therapeutics.

MicroRNA-Related Polymorphisms in Infectious Diseases-Tiny Changes With a Huge Impact on Viral Infections and Potential Clinical Applications

MicroRNAs (miRNAs) are single-stranded sequences of non-coding RNA with approximately 22 nucleotides that act posttranscriptionally on gene expression. miRNAs are important gene regulators in physiological contexts, but they also impact the pathogenesis of various diseases. The role of miRNAs in viral infections has been explored by different authors in both population-based as well as in functional studies. However, the effect of miRNA polymorphisms on the susceptibility to viral infections and on the clinical course of these diseases is still an emerging topic. Thus, this review will compile and organize the findings described in studies that evaluated the effects of genetic variations on miRNA genes and on their binding sites, in the context of human viral diseases. In addition to discussing the basic aspects of miRNAs biology, we will cover the studies that investigated miRNA polymorphisms in infections caused by hepatitis B virus, hepatitis C virus, human immunodeficiency virus, Epstein–Barr virus, and human papillomavirus. Finally, emerging topics concerning the importance of miRNA genetic variants will be presented, focusing on the context of viral infectious diseases.

Interest of variations in microRNA-152 and -122 in a series of hepatocellular carcinomas related to hepatitis C virus infection

AIM

Hepatocellular carcinoma (HCC) is a common outcome of chronic hepatitis C virus (HCV) infection and constitutes the main burden of this disease. The molecular mechanisms underlying the development of HCC are multiple and might involve certain microRNA (miR). As discordant results have been reported concerning the detection of expression of miR-152 and miR-122 in HCC, our aim was to measure the levels of both miRs in serum and liver samples.

METHODS

We analyzed miR-152 and miR-122 expression by reverse transcription-quantitative polymerase chain reaction in a serum cohort from 14 HCV-infected patients who developed HCC, 20 HCV+ patients without HCC, and 19 control patients. We also studied miR-152 and miR-122 in an independent tissue cohort from 11 normal livers, and from paired HCC and non-tumor adjacent livers of 11 HCV-infected patients and 12 non-infected patients.

RESULTS

In serum samples, higher levels of miR-122 were found in non-HCC HCV+ compared to HCC HCV+ and control groups, whereas miR-152 was detectable in a lower range in HCC HCV+ compared to non-HCC HCV+ and control groups. We found higher signals for miR-122 and miR-152 in non-tumor liver and HCC tissues compared to control tissues. Hepatocellular carcinoma etiology had no detectable influence on miR-122 expression, whereas miR-152 was increased in HCV+ tissue samples.

CONCLUSIONS

Detection of low values of circulating miR-152 is a potentially interesting marker of hepatocarcinogenesis in HCV+ patients, in contrast to miR-122, which varies according to hepatocyte damage.

Hepatitis C Virus-Associated Cancers

Most hepatitis C virus (HCV) infection results in persistent infection. Significant portion of chronic HCV-infected patients develop hepatocellular carcinoma (HCC). Chronic hepatitis C is also associated with extrahepatic manifestations, including cryoglobulinemia, lymphoma, insulin resistance, type 2 diabetes, and neurological disorders. The molecular mechanisms of how HCV infection causes liver cancer are largely unknown. HCV replication or viral proteins may perturb cellular hemostasis and induce the generation of reactive oxygen species (ROS); viral components or viral replication products act as agonist to trigger innate immune response and cause chronic inflammation. Within the liver, non-hepatocytes such as hepatic stellate cell (HSC) are activated upon HCV infection to provide the major source of extracellular proteins and play important roles in fibrogenesis. With the great achievements of HCV treatment, especially the direct-acting antivirals (DAAs) against HCV, HCV eradication is possible. However, until now there are only very limited data on the effect of DAA-based anti-HCV treatment on HCC patients.

Viral hepatitis and liver cancer

Hepatitis B and C viruses are a global health problem causing acute and chronic infections that can lead to liver cirrhosis and hepatocellular carcinoma (HCC). These infections are the leading cause for HCC worldwide and are associated with significant mortality, accounting for more than 1.3 million deaths per year. Owing to its high incidence and resistance to treatment, liver cancer is the second leading cause of cancer-related death worldwide, with HCC representing approximately 90% of all primary liver cancer cases. The majority of viral-associated HCC cases develop in subjects with liver cirrhosis; however, hepatitis B virus infection can promote HCC development without prior end-stage liver disease. Thus, understanding the role of hepatitis B and C viral infections in HCC development is essential for the future design of treatments and therapies for this cancer. In this review, we summarize the current knowledge on hepatitis B and C virus hepatocarcinogenesis and highlight direct and indirect risk factors.

This article is part of the themed issue ‘Human oncogenic viruses’.

The life of U6 small nuclear RNA, from cradle to grave

Removal of introns from precursor messenger RNA (pre-mRNA) and some noncoding transcripts is an essential step in eukaryotic gene expression. In the nucleus, this process of RNA splicing is carried out by the spliceosome, a multi-megaDalton macromolecular machine whose core components are conserved from yeast to humans. In addition to many proteins, the spliceosome contains five uridine-rich small nuclear RNAs (snRNAs) that undergo an elaborate series of conformational changes to correctly recognize the splice sites and catalyze intron removal. Decades of biochemical and genetic data, along with recent cryo-EM structures, unequivocally demonstrate that U6 snRNA forms much of the catalytic core of the spliceosome and is highly dynamic, interacting with three snRNAs, the pre-mRNA substrate, and >25 protein partners throughout the splicing cycle. This review summarizes the current state of knowledge on how U6 snRNA is synthesized, modified, incorporated into snRNPs and spliceosomes, recycled, and degraded.

MicroRNA 122, Regulated by GRLH2, Protects Livers of Mice and Patients From Ethanol-Induced Liver Disease

BACKGROUND & AIMS

Chronic, excessive alcohol consumption leads to alcoholic liver disease (ALD) characterized by steatosis, inflammation, and eventually cirrhosis. The hepatocyte specific microRNA 122 (MIR122) regulates hepatocyte differentiation and metabolism. We investigated whether an alcohol-induced decrease in level of MIR122 contributes to development of ALD.

METHODS

We obtained liver samples from 12 patients with ALD and cirrhosis and 9 healthy individuals (controls) and analyzed them by histology and immunohistochemistry. C57Bl/6 mice were placed on a Lieber-DeCarli liquid diet, in which they were fed ethanol for 8 weeks, as a model of ALD, or a control diet. These mice were also given injections of CCl4, to increase liver fibrosis, for 8 weeks. On day 28, mice with ethanol-induced liver disease and advanced fibrosis, and controls, were given injections of recombinant adeno-associated virus 8 vector that expressed the primary miR-122 transcript (pri-MIR122, to overexpress MIR122 in hepatocytes) or vector (control). Two weeks before ethanol feeding, some mice were given injections of a vector that expressed an anti-MIR122, to knock down its expression. Serum and liver tissues were collected; hepatocytes and liver mononuclear cells were analyzed by histology, immunoblots, and confocal microscopy. We performed in silico analyses to identify targets of MIR122 and chromatin immunoprecipitation quantitative polymerase chain reaction analyses in Huh-7 cells.

RESULTS

Levels of MIR122 were decreased in liver samples from patients with ALD and mice on the Lieber-DeCarli diet, compared with controls. Transgenic expression of MIR122 in hepatocytes of mice with ethanol-induced liver disease and advanced fibrosis significantly reduced serum levels of alanine aminotransferase (ALT) and liver steatosis and fibrosis, compared with mice given injections of the control vector. Ethanol feeding reduced expression of pri-MIR122 by increasing expression of the spliced form of the transcription factor grainyhead like transcription factor 2 (GRHL2) in liver tissues from mice. Levels of GRHL2 also were increased in liver tissues from patients with ALD, compared with controls; increases correlated with decreases in levels of MIR122 in human liver. Mice given injections of the anti-MIR122 before ethanol feeding had increased steatosis, inflammation, and serum levels of alanine aminotransferase compared with mice given a control vector. Levels of hypoxia-inducible factor 1 alpha (HIF1α) mRNA, a target of MIR122, were increased in liver tissues from patients and mice with ALD, compared with controls. Mice with hepatocyte-specific disruption of Hif1α developed less-severe liver injury following administration of ethanol, injection of anti-MIR122, or both.

CONCLUSIONS

Levels of MIR122 decrease in livers from patients with ALD and mice with ethanol-induced liver disease, compared with controls. Transcription of MIR122 is inhibited by GRHL2, which is increased in livers of mice and patients with ALD. Expression of an anti-MIR122 worsened the severity of liver damage following ethanol feeding in mice. MIR122 appears to protect the liver from ethanol-induced damage by reducing levels of HIF1α. These processes might be manipulated to reduce the severity of ALD in patients.

Differential hepatitis C virus RNA target site selection and host factor activities of naturally occurring miR-122 3΄ variants

In addition to suppressing cellular gene expression, certain miRNAs potently facilitate replication of specific positive-strand RNA viruses. miR-122, a pro-viral hepatitis C virus (HCV) host factor, binds and recruits Ago2 to tandem sites (S1 and S2) near the 5΄ end of the HCV genome, stabilizing it and promoting its synthesis. HCV target site selection follows canonical miRNA rules, but how non-templated 3΄ miR-122 modifications impact this unconventional miRNA action is unknown. High-throughput sequencing revealed that a 22 nt miRNA with 3΄G (‘22–3΄G’) comprised <63% of total miR-122 in human liver, whereas other variants (23–3΄A, 23–3΄U, 21–3΄U) represented 11–17%. All loaded equivalently into Ago2, and when tested individually functioned comparably in suppressing gene expression. In contrast, 23–3΄A and 23–3΄U were more active than 22–3΄G in stabilizing HCV RNA and promoting its replication, whereas 21–3΄U was almost completely inactive. This lack of 21–3΄U HCV host factor activity correlated with reduced recruitment of Ago2 to the HCV S1 site. Additional experiments demonstrated strong preference for guanosine at nt 22 of miR-122. Our findings reveal the importance of non-templated 3΄ miR-122 modifications to its HCV host factor activity, and identify unexpected differences in miRNA requirements for host gene suppression versus RNA virus replication.

Hepatitis B virus X protein-induced upregulation of CAT-1 stimulates proliferation and inhibits apoptosis in hepatocellular carcinoma cells

The HBx protein of hepatitis B virus (HBV) is widely recognized to be a critical oncoprotein contributing to the development of HBV-related hepatocellular carcinoma (HCC). In addition, cationic amino acid transporter 1 (CAT-1) gene is a target of miR-122. In this study, we found that CAT-1 protein levels were higher in HBV-related HCC carcinomatous tissues than in para-cancerous tumor tissues, and that CAT-1 promoted HCC cell growth, proliferation, and metastasis. Moreover, HBx-induced decreases in Gld2 and miR-122 levels that contributed to the upregulation of CAT-1 in HCC. These results indicate that a Gld2/miR-122/CAT-1 pathway regulated by HBx likely participates in HBV-related hepatocellular carcinogenesis.

Unraveling the Mysterious Interactions Between Hepatitis C Virus RNA and Liver-Specific MicroRNA-122

Many viruses encode or subvert cellular microRNAs (miRNAs) to aid in their gene expression, amplification strategies, or pathogenic signatures. miRNAs typically downregulate gene expression by binding to the 3' untranslated region of their mRNA targets. As a result, target mRNAs are translationally repressed and subsequently deadenylated and degraded. Curiously, hepatitis C virus (HCV), a member of the Flaviviridae family, recruits two molecules of liver-specific microRNA-122 (miR-122) to the 5' end of its genome. In contrast to the canonical activity of miRNAs, the interactions of miR-122 with the viral genome promote viral RNA accumulation in cultured cells and in animal models of HCV infection. Sequestration of miR-122 results in loss of viral RNA both in cell culture and in the livers of chronic HCV-infected patients. This review discusses the mechanisms by which miR-122 is thought to enhance viral RNA abundance and the consequences of miR-122-HCV interactions. We also describe preliminary findings from phase II clinical trials in patients treated with miR-122 antisense oligonucleotides.

Achieving sustained virologic response after interferon-free hepatitis C virus treatment correlates with hepatic interferon gene expression changes independent of cirrhosis

Chronic hepatitis C virus (HCV) infection can now be treated with oral directly acting antiviral agents, either with or without ribavirin (RBV). Virologic relapse after treatment can occur, and in some studies was more common in cirrhotic subjects. We previously observed changes in hepatic immunity during interferon (IFN)-free therapy that correlated with favourable outcome in subjects with early liver disease. Here, we compared changes in endogenous IFN pathways during IFN-free, RBV-free therapy between cirrhotic and noncirrhotic subjects. mRNA and microRNA (miRNA) expression analyses were performed on paired pre- and post-treatment liver biopsies from genotype-1 HCV subjects treated with sofosbuvir/ledipasvir (SOF/LDV) for 12 weeks (n = 4, 3 cirrhotics) or SOF/LDV combined with GS-9669 or GS-9451 for 6 weeks (n = 6, 0 cirrhotics). Nine of ten subjects achieved a sustained virologic response (SVR), while one noncirrhotic subject relapsed. Hepatic IFN-stimulated gene expression decreased with treatment in the liver of all subjects, with no observable impact of cirrhosis. Hepatic gene expression of type III IFNs (IFNL1, IFNL3, IFNL4-ΔG) similarly decreased with treatment, while IFNA2 expression, undetectable in all subjects pretreatment, was detected post-treatment in three subjects who achieved a SVR. Only the subject who relapsed had detectable IFNL4-ΔG expression in post-treatment liver. Other IFNs had no change in gene expression (IFNG, IFNB1, IFNA5) or could not be detected. Although expression of multiple hepatic miRNAs changed with treatment, many miRNAs previously implicated in HCV replication and IFN signalling had unchanged expression. In conclusion, favourable treatment outcome during IFN-free HCV therapy is associated with changes in the host IFN response regardless of cirrhosis.

MicroRNAs as possible biomarkers for diagnosis and prognosis of hepatitis B- and C-related-hepatocellular-carcinoma

Aim of the present review is to summarize the current knowledge about the potential relationship between miRNAs and hepatitis B virus (HBV)-hepatitis C virus (HCV) related liver diseases. A systematic computer-based search of published articles, according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis Statement, was performed to identify relevant studies on usefulness of serum/plasma/urine miRNAs, as noninvasive biomarkers for early detection of HBV and HCV-induced hepatocellular carcinoma (HCC) development, as well as for its prognostic evaluation. The used Medical Subject Headings terms and keywords were: "HBV", "HCV", "hepatocellular carcinoma", "microRNAs", "miRNAs", "diagnosis", "prognosis", "therapy", "treatment". Some serum/plasma miRNAs, including miR-21, miR-122, mi-125a/b, miR-199a/b, miR-221, miR-222, miR-223, miR-224 might serve as biomarkers for early diagnosis/prognosis of HCC, but, to date, not definitive results or well-defined panels of miRNAs have been obtained. More well-designed studies, focusing on populations of different geographical areas and involving larger series of patients, should be carried out to improve our knowledge on the potential role of miRNAs for HCC early detection and prognosis.

The Liver MicroRNA Expression Profiles Associated With Chronic Hepatitis C Virus (HCV) Genotype-4 Infection: A Preliminary Study

BACKGROUND

MicroRNAs (miRNAs) have been repeatedly shown to play important roles in liver pathologies, including hepatitis, liver cirrhosis, and liver cancer. Egypt has the highest hepatitis C virus (HCV) infection rate worldwide, predominantly involving genotype-4.

OBJECTIVES

In this study, we attempted to characterize the miRNA profile of the poorly studied genotype 4 of HCV in chronically infected Egyptian patients to obtain a better understanding of the disease and its complications and help in the design of better management protocols.

PATIENTS AND METHODS

We analyzed the expression levels of a selected panel of 94 miRNAs in fresh liver biopsies collected from 50 Egyptian patients diagnosed with chronic HCV infection using quantitative real-time polymerase chain reaction (PCR) assay. Non-parametric tests were used to analyze the expression level of each miRNA and association with the clinicopathological features of enrolled patients in this study.

RESULTS

Our results revealed differential expression levels of the analyzed miRNAs compared to the normal controls. Twenty-seven miRNAs (including miR-105, miR-147, miR-149-3p, and miR-196b) showed up-regulation, while 17 miRNAs (including miR-21, miR-122, miR-199a-3p, and miR-223) showed down-regulation. An inverse correlation was observed between levels of miR-95, miR-130a, and miR-142-5p with the blood albumin level. Increased expression levels of seven miRNAs (miR-29c, miR-30c, miR-126, miR-145, miR-199a, miR-199a-3p, and miR-222) were observed with severe chronic hepatic inflammation. Several deregulated miRNAs found in this study have been previously linked to chronic liver inflammation and the risk of hepatocellular carcinoma (HCC) development.

CONCLUSIONS

The identified expression profiles of some examined miRNAs might offer important points to consider for the treatment of naive patients and the management of chronically infected HCV patients in Egypt and around the world.

Diminished viral replication and compartmentalization of hepatitis C virus in hepatocellular carcinoma tissue

Analysis of hepatitis C virus (HCV) replication and quasispecies distribution within the tumor of patients with HCV-associated hepatocellular carcinoma (HCC) can provide insight into the role of HCV in hepatocarcinogenesis and, conversely, the effect of HCC on the HCV lifecycle. In a comprehensive study of serum and multiple liver specimens from patients with HCC who underwent liver transplantation, we found a sharp and significant decrease in HCV RNA in the tumor compared with surrounding nontumorous tissues, but found no differences in multiple areas of control non-HCC cirrhotic livers. Diminished HCV replication was not associated with changes in miR-122 expression. HCV genetic diversity was significantly higher in livers containing HCC compared with control non-HCC cirrhotic livers. Tracking of individual variants demonstrated changes in the viral population between tumorous and nontumorous areas, the extent of which correlated with the decline in HCV RNA, suggesting HCV compartmentalization within the tumor. In contrast, compartmentalization was not observed between nontumorous areas and serum, or in controls between different areas of the cirrhotic liver or between liver and serum. Our findings indicate that HCV replication within the tumor is restricted and compartmentalized, suggesting segregation of specific viral variants in malignant hepatocytes.

Transcriptomic Analysis of Chronic Hepatitis B and C and Liver Cancer Reveals MicroRNA-Mediated Control of Cholesterol Synthesis Programs

Chronic hepatitis B (CHB), chronic hepatitis C (CHC), and associated hepatocellular carcinoma (HCC) are characterized by cholesterol imbalance and dyslipidemia; however, the key regulatory drivers of these phenotypes are incompletely understood. Using gene expression microarrays and high-throughput sequencing of small RNAs, we performed integrative analysis of microRNA (miRNA) and gene expression in nonmalignant and matched cancer tissue samples from human subjects with CHB or CHC and HCC. We also carried out follow-up functional studies of specific miRNAs in a cell-based system. These studies led to four major findings. First, pathways affecting cholesterol homeostasis were among the most significantly overrepresented among genes dysregulated in chronic viral hepatitis and especially in tumor tissue. Second, for each disease state, specific miRNA signatures that included miRNAs not previously associated with chronic viral hepatitis, such as miR-1307 in CHC, were identified. Notably, a few miRNAs, including miR-27 and miR-224, were components of the miRNA signatures of all four disease states: CHB, CHC, CHB-associated HCC, and CHC-associated HCC. Third, using a statistical simulation method (miRHub) applied to the gene expression data, we identified candidate master miRNA regulators of pathways controlling cholesterol homeostasis in chronic viral hepatitis and HCC, including miR-21, miR-27, and miR-33. Last, we validated in human hepatoma cells that both miR-21 and miR-27 significantly repress cholesterol synthesis and that miR-27 does so in part through regulation of the gene that codes for the rate-limiting enzyme 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase (HMGCR).

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are phylogenetically unrelated hepatotropic viruses that persistently infect hundreds of millions of people world-wide, often leading to chronic liver disease and hepatocellular carcinoma (HCC). Chronic hepatitis B (CHB), chronic hepatitis C (CHC), and associated HCC often lead to cholesterol imbalance and dyslipidemia. However, the regulatory mechanisms underlying the dysregulation of lipid pathways in these disease states are incompletely understood. MicroRNAs (miRNAs) have emerged as critical modulators of lipid homeostasis. Here we use a blend of genomic, molecular, and biochemical strategies to identify key miRNAs that drive the lipid phenotypes of chronic viral hepatitis and HCC. These findings provide a panoramic view of the miRNA landscape in chronic viral hepatitis, which could contribute to the development of novel and more-effective miRNA-based therapeutic strategies.

How do persistent infections with hepatitis C virus cause liver cancer?

Persistent infection with hepatitis C virus (HCV) is associated with an increased risk of hepatocellular carcinoma (HCC). Cancer typically develops in a setting of chronic hepatic inflammation and advanced fibrosis or cirrhosis, and such tissue represents a pre-neoplastic 'cancer field'. However, not all persistent infections progress to HCC and a combination of viral and host immune factors likely contributes to carcinogenesis. HCV may disrupt cellular pathways involved in detecting and responding to DNA damage, potentially adding to the risk of cancer. Efforts to unravel how HCV promotes HCC are hindered by lack of a robust small animal model, but a better understanding of molecular mechanisms could identify novel biomarkers for early detection and allow for development of improved therapies.

Hepatitis B virus and microRNAs: Complex interactions affecting hepatitis B virus replication and hepatitis B virus-associated diseases

Chronic infection with the hepatitis B virus (HBV) is the leading risk factor for the development of hepatocellular carcinoma (HCC). With nearly 750000 deaths yearly, hepatocellular carcinoma is the second highest cause of cancer-related death in the world. Unfortunately, the molecular mechanisms that contribute to the development of HBV-associated HCC remain incompletely understood. Recently, microRNAs (miRNAs), a family of small non-coding RNAs that play a role primarily in post-transcriptional gene regulation, have been recognized as important regulators of cellular homeostasis, and altered regulation of miRNA expression has been suggested to play a significant role in virus-associated diseases and the development of many cancers. With this in mind, many groups have begun to investigate the relationship between miRNAs and HBV replication and HBV-associated disease. Multiple findings suggest that some miRNAs, such as miR-122, and miR-125 and miR-199 family members, are playing a role in HBV replication and HBV-associated disease, including the development of HBV-associated HCC. In this review, we discuss the current state of our understanding of the relationship between HBV and miRNAs, including how HBV affects cellular miRNAs, how these miRNAs impact HBV replication, and the relationship between HBV-mediated miRNA regulation and HCC development. We also address the impact of challenges in studying HBV, such as the lack of an effective model system for infectivity and a reliance on transformed cell lines, on our understanding of the relationship between HBV and miRNAs, and propose potential applications of miRNA-related techniques that could enhance our understanding of the role miRNAs play in HBV replication and HBV-associated disease, ultimately leading to new therapeutic options and improved patient outcomes.

MiR-122 in hepatitis B virus and hepatitis C virus dual infection

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are the most common causes of chronic liver diseases and hepatocelluar carcinomas. Over the past few years, the liver-enriched microRNA-122 (miR-122) has been shown to differentially regulate viral replication of HBV and HCV. It is notable that the level of miR-122 is positively and negatively regulated by HCV and HBV, respectively. Consistent with the well-documented phenomenon that miR-122 promotes HCV accumulation, inhibition of miR-122 has been shown as an effective therapy for the treatment of HCV infection in both chimpanzees and humans. On the other hand, miR-122 is also known to block HBV replication, and HBV has recently been shown to inhibit miR-122 expression; such a reciprocal inhibition between miR-122 and HBV suggests an intriguing possibility that miR-122 replacement may represent a potential therapy for treatment of HBV infection. As HBV and HCV have shared transmission routes, dual infection is not an uncommon scenario, which is associated with more advanced liver disease than either HBV or HCV mono-infection. Thus, there is a clear need to further understand the interaction between HBV and HCV and to delineate the role of miR-122 in HBV/HCV dual infection in order to devise effective therapy. This review summarizes the current understanding of HBV/HCV dual infection, focusing on the pathobiological role and therapeutic potential of miR-122.

miR-122--a key factor and therapeutic target in liver disease

Being the largest internal organ of the human body with the unique ability of self-regeneration, the liver is involved in a wide variety of vital functions that require highly orchestrated and controlled biochemical processes. Increasing evidence suggests that microRNAs (miRNAs) are essential for the regulation of liver development, regeneration and metabolic functions. Hence, alterations in intrahepatic miRNA networks have been associated with liver disease including hepatitis, steatosis, cirrhosis and hepatocellular carcinoma (HCC). miR-122 is the most frequent miRNA in the adult liver, and a central player in liver biology and disease. Furthermore, miR-122 has been shown to be an essential host factor for hepatitis C virus (HCV) infection and an antiviral target, complementary to the standard of care using direct-acting antivirals or interferon-based treatment. This review summarizes our current understanding of the key role of miR-122 in liver physiology and disease, highlighting its role in HCC and viral hepatitis. We also discuss the perspectives of miRNA-based therapeutic approaches for viral hepatitis and liver disease.

Small tRNA-derived RNAs are increased and more abundant than microRNAs in chronic hepatitis B and C

Persistent infections with hepatitis B virus (HBV) or hepatitis C virus (HCV) account for the majority of cases of hepatic cirrhosis and hepatocellular carcinoma (HCC) worldwide. Small, non-coding RNAs play important roles in virus-host interactions. We used high throughput sequencing to conduct an unbiased profiling of small (14-40 nts) RNAs in liver from Japanese subjects with advanced hepatitis B or C and hepatocellular carcinoma (HCC). Small RNAs derived from tRNAs, specifically 30–35 nucleotide-long 5′ tRNA-halves (5′ tRHs), were abundant in non-malignant liver and significantly increased in humans and chimpanzees with chronic viral hepatitis. 5′ tRH abundance exceeded microRNA abundance in most infected non-cancerous tissues. In contrast, in matched cancer tissue, 5′ tRH abundance was reduced, and relative abundance of individual 5′ tRHs was altered. In hepatitis B-associated HCC, 5′ tRH abundance correlated with expression of the tRNA-cleaving ribonuclease, angiogenin. These results demonstrate that tRHs are the most abundant small RNAs in chronically infected liver and that their abundance is altered in liver cancer.

MicroRNAs in liver cancer: a model for investigating pathogenesis and novel therapeutic approaches

MicroRNAs (miRNAs) constitute a large class of short RNAs (e.g., 20-24 nucleotides in length), whose main function is to posttranscriptionally regulate the expression of protein-coding genes. Their importance in tumorigenesis has been demonstrated over the past decade, and correspondingly, they have emerged as potential therapeutic molecules and targets. Liver cancer is one of the most common neoplastic diseases worldwide, and it currently has a poor prognosis owing to largely ineffective therapeutic options. Liver cancer is also an excellent model for testing miRNA-based therapy approaches as it can be easily targeted with the systemic delivery of oligonucleotides. In recent years, the role of miRNAs in hepatocellular carcinoma (HCC) has been established with molecular studies and the development of animal models. These studies have also provided the basis for evaluating the therapeutic potential of miRNAs, or anti-miRNAs. In general, the safety of miRNAs has been proven and antitumor activity has been observed. Moreover, because of the absence or presence of mild side effects, the prophylactic use of miRNA-based approaches may be foreseen.

Association between four common microRNA polymorphisms and the risk of hepatocellular carcinoma and HBV infection

microRNAs (miR/miRNAs) have been demonstrated to function as tumor suppressors and oncogenes, and miRNA polymorphisms may have a role in cancer development. The present study aimed to investigate the association between the miR-146aG>C, miR-149C>T, miR-196a2C>T and miR-499A>G polymorphisms and the risk of hepatocellular carcinoma (HCC) and hepatitis B virus (HBV) infection. A total of 271 patients with HCC and 532 healthy control participants were enrolled in the present study. miR-146aG>C, miR-149C>T, miR-196a2C>T and miR-499A>G polymorphisms were genotyped using the polymerase chain reaction-restriction fragment length polymorphism method. A significant difference was identified in the genotype frequency of miR-196a2C>T in the patients in the case group compared with the control group (χ²=6.88; P=0.032). Compared with the CC genotype, the miR-196a2 TT genotype was associated with a significantly reduced risk of HCC [odds ratio (OR), 0.62; 95% confidence interval (CI), 0.38–0.99], and a significantly reduced risk was also found in the dominant (OR, 0.69; 95% CI, 0.49–0.98) and recessive (OR, 0.70; 95% CI, 0.46–1.02) models. Moreover, individuals with HBV who were carrying the miR-196a2 CT and TT genotypes had a significantly reduced risk of HCC (OR, 0.62; 95% CI, 0.41–0.95; and OR, 0.39; 95% CI, 0.20–0.73, respectively). In conclusion, the present study found that the miR-196a2C>T polymorphism has a protective effect in patients with HCC, particularly in those with HBV infection.

Regulation of microRNAs and their role in liver development, regeneration and disease

Since their discovery more than a decade ago microRNAs have been demonstrated to have profound effects on almost every aspect of biology. Numerous studies in recent years have shown that microRNAs have important roles in development and in the etiology and progression of disease. This review is focused on microRNAs and the roles they play in liver development, regeneration and liver disease; particularly chronic liver diseases such as alcoholic liver disease, non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, viral hepatitis and primary liver cancer. The key microRNAs identified in liver development and chronic liver disease will be discussed together with, where possible, the target messenger RNAs that these microRNAs regulate to profoundly alter these processes. This article is part of a Directed Issue entitled: The Non-coding RNA Revolution.

Suramin inhibits hepatic tissue damage in hepatocellular carcinoma through deactivation of heparanase enzyme

Hepatocellular carcinoma (HCC) is resistant to conventional chemotherapy, and is rarely amenable to radiotherapy. Heparanase, enzyme attacks heparan sulfate proteoglycans (HSPGs), is preferentially expressed in human tumors and its overexpression in low-metastatic tumor confers a highly invasive phenotype in experimental animals. Meanwhile, high doses of suramin dramatically increase tissue glycosaminoglycans due, in part, to inhibition of heparanase enzymes. Therefore, the following study was conducted to evaluate the chemopreventive and hepatoprotective effects of suramin in in-vivo model of HCC. Therefore, HCC was induced in SD rats by thioacetamide (200mg/kg) in presence/absence of suramin (20mg/kg). Liver impairment was assessed by measuring serum α-fetoprotein and investigating liver sections stained with Hematoxylin/Eosin. Hepatic HSPGs and heparanse were measured by ELISA. Glucosamine and glucuronic acid were measured by chemical methods. Gene expression of fibroblast growth factor (FGF)-2 and caspase-3 was measured. Apoptotic pathway was evaluated by measuring the activity of caspase-3/8/9. Suramin increased the animal survival and decreased serum α-fetoprotein. In addition, suramin ameliorated fibrosis and massive hepatic tissue breakdown. Suramin restored hepatic HSPGs and reduced the activity of hepatic heparanase leading to decreased hepatic levels of glucosamine and glucuronic acid. Moreover, suramin reduced the gene expression of FGF-2 and caspase-3. Finally, suramin blocked the elevated activity of caspase-3/8/9. In conclusion, surmain showed antitumor activity as well as hepatoprotective effects. Besides its antioxidant activity, other mechanisms are involved including restoration of HSPGs and inhibition of heparanase and FGF-2. Suramin inhibits intrinsic and extrinsic apoptotic pathway. Targeting HSPGs expression is potential therapeutic target for HCC.

Long-term day-and-night rotating shift work poses a barrier to the normalization of alanine transaminase

To evaluate the impact of day-and-night rotating shift work (RSW) on liver health, we performed a retrospective analysis of the association between long-term RSW exposure and the normalization of plasma alanine transaminase (ALT) levels over a five-year period. The data from physical examinations, blood tests, abdominal sonographic examinations, personal histories, and occupational records were collected from a cohort of workers in a semiconductor manufacturing company. The sample population was divided into three subgroups for analysis, according to self-reported shift work status over the five-year interval: persistent daytime workers, workers exposed intermittently to RSW (i-RSW), and workers exposed persistently to RSW (p-RSW). Records were analyzed for 1196 male workers with an initial mean age of 32.5 years (SD 6.0 years), of whom 821 (68.7%) were identified as rotating shift workers, including 374 i-RSW (31.3%) and 447 p-RSW workers (37.4%). At the beginning of the follow-up, 275 were found to have elevated ALT (e-ALT): 25.1% daytime workers, 23.0% i-RSW workers, and 21.3% p-RSW workers (p = 0.098). Of those with e-ALT at the beginning, 101 workers showed normalized serum ALT levels at the end of five-year follow-up: 40 (10.7%) of 375 daytime workers, 32 (8.6%) of 374 i-RSW workers, and 29 (6.5%) of 447 p-RSW workers (p = 0.016). Compared with the workers having persistent e-ALT at the end of follow-up, the workers normalized serum ALT levels had significantly lesser exposures to RSW during follow-up. By performing multivariate logistic regression analyses, and comparing with the persistent daytime co-workers, after controlling for confounding variables (age, occupational factors, educational levels, lifestyle factors, metabolic syndrome, hepatovirus infection, and fatty liver), analysis indicated that the workers exposed to p-RSW were 46% less likely (OR, 0.54; 95% CI, 0.30-0.95; p = 0.03) to attain normal ALT levels within a five-year interval. These observations demonstrate that persistent day-and-night RSW pose a vigorous obstacle to the normalization of e-ALT among workers with preexisting abnormal liver function. We suggest that workers and managers approach with caution the consideration of assigning or accepting long-term day-and-night RSW when an employee health screening shows evidence of abnormal liver function.