Serum microRNA-122 kinetics in patients with chronic hepatitis C virus infection during antiviral therapy

Molecular Targets and Signaling Pathways of microRNA-122 in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading global causes of cancer mortality. MicroRNAs (miRNAs) are small interfering RNAs that alleviate the levels of protein expression by suppressing translation, inducing mRNA cleavage, and promoting mRNA degradation. miR-122 is the most abundant miRNA in the liver and is responsible for several liver-specific functions, including metabolism, cellular growth and differentiation, and hepatitis virus replication. Recent studies have shown that aberrant regulation of miR-122 is a key factor contributing to the development of HCC. In this review, the signaling pathways and the molecular targets of miR-122 involved in the progression of HCC have been summarized, and the importance of miR-122 in therapy has been discussed.

Serum Expression Level of MicroRNA-122 and Its Significance in Patients with Hepatitis B Virus Infection

OBJECTIVES

To analyze the expression of miR-122 and evaluate its significance in patients with HBV infection in different phases.

METHODS

Eleven chronic hepatitis B (CHB), 26 hepatitis B virus (HBV)-induced cirrhosis, 16 HBV-associated hepatocellular carcinoma (HCC) patients and 10 healthy control cases were enrolled. The serum levels of miR-122 were detected by RT-PCR and compared between healthy individuals and CHB at different stages.

RESULTS

Compared with healthy control cases, serum miR-122 levels were markedly increased in HBV infection cases (AUC = 0.795, P=0.002). In the CHB group, miR-122 levels were positively associated with albumin levels (P < 0.05) but had no significant associations with alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (P > 0.05). In the cirrhosis group, miR-122 expression was remarkably lower in the Child C group in comparison with the Child A group (P=0.025). At the same time, miR-122 amounts had a negative correlation with HVPG (P < 0.05). In the HCC group, miR-122 amounts were negatively associated with alkaline phosphatase (AKP) and alpha-fetoprotein (AFP) (P < 0.05). Serum miR-122 amounts in 3 patients who died were lower than the survival group (5.520 ± 0.522 vs. 5.860 ± 1.183, P > 0.05).

CONCLUSION

Serum miR-122 can be leveraged to screen patients with HBV infection. In HBV sufferers, the serum miR-122 expression level is related to liver disease progression, hence making it an underlying molecular biomarker for predicting the development of CHB.

Mammalian antiviral systems directed by small RNA

There are strong incentives for human populations to develop antiviral systems. Similarly, genomes that encode antiviral systems have had strong selective advantages. Protein-guided immune systems, which have been well studied in mammals, are necessary for survival in our virus-laden environments. Small RNA–directed antiviral immune systems suppress invasion of cells by non-self genetic material via complementary base pairing with target sequences. These RNA silencing-dependent systems operate in diverse organisms. In mammals, there is strong evidence that microRNAs (miRNAs) regulate endogenous genes important for antiviral immunity, and emerging evidence that virus-derived nucleic acids can be directly targeted by small interfering RNAs (siRNAs), PIWI-interacting RNAs (piRNAs), and transfer RNAs (tRNAs) for protection in some contexts. In this review, we summarize current knowledge of the antiviral functions of each of these small RNA types and consider their conceptual and mechanistic overlap with innate and adaptive protein-guided immunity, including mammalian antiviral cytokines, as well as the prokaryotic RNA-guided immune system, CRISPR. In light of recent successes in delivery of RNA for antiviral purposes, most notably for vaccination, we discuss the potential for development of small noncoding RNA–directed antiviral therapeutics and prophylactics.

Viruses are all around us and are likely inside some of the reader’s cells at this moment. Organisms are accommodated to this reality and encode various immune systems to limit virus replication. In mammals, the best studied immune systems are directed by proteins that specifically recognize viruses. These include diverse antibodies and T cell receptors, which recognize viral proteins, and pattern recognition receptors, some of which can recognize viral nucleic acids. In other organisms, including bacteria, immune systems directed by small RNAs are also well known; spacer-derived guide RNAs in CRISPR/Cas immune systems are one prominent example. The small RNAs directing these systems derive their specificity via complementary base pairing with their targets, which include both host and viral nucleic acids. Rather than having “traded in” these systems for more advanced protein-directed systems, increasing evidence supports the perspective that small RNA–directed immune systems remain active in mammalian antiviral immunity in some contexts. Here, we review what is known so far about the emerging roles of mammalian siRNAs, miRNAs, piRNAs, and tRNAs in directing immunity to viruses.

Evaluation of miR-122 Serum Level and IFN-λ3 Genotypes in Patients with Chronic HCV and HCV-Infected Liver Transplant Candidate

BACKGROUND

Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are the most common markers of liver damage, but serum level interpretation can be complicated. In hepatocytes, microRNA-122 (miR-122) is the most abundant miRs and its high expression in the serum is a characteristic of liver disease.

OBJECTIVE

We aimed to compare the circulatory level of miR-122 in patients with Chronic Hepatitis C (CHC), Hepatitis C Virus (HCV) infected Liver Transplant Candidates (LTC) and healthy controls to determine if miR-122 can be considered as an indicator of chronic and advanced stage of liver disease.

METHODS

MiR-122 serum level was measured in 170 Interferon-naïve (IFN-naïve) CHC patients, 62 LTC patients, and 132 healthy individuals via TaqMan real-time PCR. Serum levels of miR-122 were normalized to the serum level of Let-7a and miR-221. Also, the ALT and AST levels were measured.

RESULTS

ALT and AST activities and the expression of circulatory miR-122 were similar in the CHC and LTC groups, but it had significantly increased compared to healthy individuals (P<0.001 and P<0.001, respectively). Up-regulation of miR-122 in the sample of patients with normal ALT and AST activities was also observed, indicating that miR-122 is a good marker with high sensitivity and specificity for diagnosing liver damage.

CONCLUSION

miR-122 seemed to be more specific for liver diseases in comparison with the routine ALT and AST liver enzymes. Since the lower levels of circulating miR-122 were observed in the LTC group compared to the CHC group, advanced liver damages might reduce the release of miR-122 from the hepatocytes, as a sign of liver function deficiency.

Serum levels of miR-223 but not miR-21 are decreased in patients with neuroendocrine tumors

Background and aims

MicroRNAs (miRNAs) are profoundly involved into the pathophysiology of manifold cancers. Recent data suggested a pivotal role of miRNAs as biomarkers in different biological processes including carcinogenesis. However, their role in neuroendocrine tumors (NETs) is only poorly understood.

Methods

We determined circulating levels of miR-21 and miR-223 in 45 samples from patients with NET treated between 2010 and 2019 at our department and compared them to healthy controls. Results were correlated with clinical records.

Results

In the total cohort of Patients with NET, miR-223 presented significantly lower levels compared to healthy control samples. In contrast, levels of miR-21 indicated no significant changes between the two groups. Interestingly, despite being significantly downregulated in all NET patients, concentrations of miR-223 were independent of clinical or histopathological factors such as proliferation activity according to Ki-67 index, tumor grading, TNM stage, somatostatin receptor expression, presence of functional/ non-functional disease or tumor relapse. Moreover, in contrast to data from recent publications analyzing other tumor entities, levels of miR-223 serum levels did not reflect prognosis of patients with NET.

Conclusion

Lower concentrations of circulating miR-223 rather reflect the presence of NET itself than certain tumor characteristics. The value of miR-223 as a biomarker in NET might be limited to diagnostic, but not prognostic purposes.

Genomics and Liver Transplantation: Genomic Biomarkers for the Diagnosis of Acute Cellular Rejection

Acute cellular rejection (ACR) is a common complication in liver transplantation recipients (LTRs), especially within the first 12 months, and it is associated with increased morbidity and mortality. Although abnormalities in standard liver biochemistries may raise the clinical suspicion for ACR, it lacks specificity, and invasive liver biopsies, which are associated with numerous risks, are required for definitive diagnoses. Biomarker discovery for minimally invasive tools for diagnosis and prognostication of ACR after liver transplantation (LT) has become a rapidly evolving field of research with a recent shift in focus to omics-based biomarker discovery. Although none are yet ready to replace the standard of care, there are several promising minimally invasive, blood-derived biomarkers that are under intensive research for the diagnosis of ACR in LTRs. These omics-based biomarkers, encompassing DNA, RNA, proteins, and metabolites, hold tremendous potential. Some are likely to become integrated into ACR diagnostic algorithms to assist clinical decision making with a high degree of accuracy that is cost-effective and reduces or even obviates the need for an invasive liver biopsy.

Changes in miR-122 and Cholesterol Expression in Chronic Hepatitis C Patients after PegIFN-Alpha/Ribavirin Treatment

The hepatitis C virus (HCV) is known as a main etiological cause of chronic hepatitis. HCV infection disturbs cholesterol metabolism of the host, which is frequently observed in patients suffering from chronic hepatitis C (CHC). The course of viral infections remains under strict control of microRNA (miRNA). In the case of HCV, miR-122 exerts a positive effect on HCV replication in vitro. The purpose of this study was to investigate the impact of peginterferon alpha (pegIFN-α) and ribavirin treatments on the expression of miR-122 and the cholesterol level in the peripheral blood mononuclear cells (PBMCs) of CHC patients. We report here that the level of miR-122 expression in the PBMCs decreased after the antiviral treatment in comparison to the pretreated state. Simultaneously, the level of cholesterol in the PBMCs of CHC patients was higher six months following the treatment than it was pretreatment. Consequently, it seems that the decrease of miR-122 expression in the PBMCs of CHC patients is one of the antiviral effects connected with the pegIFN-alpha/ribavirin treatments.

MicroRNA Biomarkers for Infectious Diseases: From Basic Research to Biosensing

In the pursuit of improved diagnostic tests for infectious diseases, several classes of molecules have been scrutinized as prospective biomarkers. Small (18–22 nucleotide), non-coding RNA transcripts called microRNAs (miRNAs) have emerged as promising candidates with extensive diagnostic potential, due to their role in numerous diseases, previously established methods for quantitation and their stability within biofluids. Despite efforts to identify, characterize and apply miRNA signatures as diagnostic markers in a range of non-infectious diseases, their application in infectious disease has advanced relatively slowly. Here, we outline the benefits that miRNA biomarkers offer to the diagnosis, management, and treatment of infectious diseases. Investigation of these novel biomarkers could advance the use of personalized medicine in infectious disease treatment, which raises important considerations for validating their use as diagnostic or prognostic markers. Finally, we discuss new and emerging miRNA detection platforms, with a focus on rapid, point-of-care testing, to evaluate the benefits and obstacles of miRNA biomarkers for infectious disease.

Hepatocellular Carcinoma Mechanisms Associated with Chronic HCV Infection and the Impact of Direct-Acting Antiviral Treatment

Hepatitis C virus (HCV) infection is the major risk factor for liver cirrhosis and hepatocellular carcinoma (HCC). The mechanisms of HCC initiation, growth, and metastasis appear to be highly complex due to the decade-long interactions between the virus, immune system, and overlapping bystander effects of host metabolic liver disease. The lack of a readily accessible animal model system for HCV is a significant obstacle to understand the mechanisms of viral carcinogenesis. Traditionally, the primary prevention strategy of HCC has been to eliminate infection by antiviral therapy. The success of virus elimination by antiviral treatment is determined by the SVR when the HCV is no longer detectable in serum. Interferon-alpha (IFN-α) and its analogs, pegylated IFN-α (PEG-IFN-α) alone with ribavirin (RBV), have been the primary antiviral treatment of HCV for many years with a low cure rate. The cloning and sequencing of HCV have allowed the development of cell culture models, which accelerated antiviral drug discovery. It resulted in the selection of highly effective direct-acting antiviral (DAA)-based combination therapy that now offers incredible success in curing HCV infection in more than 95% of all patients, including those with cirrhosis. However, several emerging recent publications claim that patients who have liver cirrhosis at the time of DAAs treatment face the risk of HCC occurrence and recurrence after viral cure. This remains a substantial challenge while addressing the long-term benefit of antiviral medicine. The host-related mechanisms that drive the risk of HCC in the absence of the virus are unknown. This review describes the multifaceted mechanisms that create a tumorigenic environment during chronic HCV infection. In addition to the potential oncogenic programming that drives HCC after viral clearance by DAAs, the current status of a biomarker development for early prediction of cirrhosis regression and HCC detection post viral treatment is discussed. Since DAAs treatment does not provide full protection against reinfection or viral transmission to other individuals, the recent studies for a vaccine development are also reviewed.

Detection of miR-122 by fluorescence real-time PCR in blood from patients with chronic hepatitis B and C infections

BACKGROUND

This study aims to determine whether relative miR-122 levels in peripheral blood are correlated with chronic hepatitis B (CHB) and chronic hepatitis C (CHC) virus infection and viral replication to determine whether miR-122 can be a new marker for liver injury.

METHODS

MicroRNA (miRNA) was extracted from the peripheral blood of 20 CHB patients, 20 CHC patients, and 20 healthy controls. The levels of miR-122 were determined using fluorescence real-time reverse transcription PCR. Then, the associations of miR-122 with CHB and CHC were analyzed, and its correlation with other markers of liver function and viral replication were determined.

RESULTS

The expression level of miR-122 in patients with CHB was significantly higher when compared to subjects in the control group (P = 0.007) or CHC patients (P = 0.005). Furthermore, the miR-122 level in patients with CHC was somewhat higher when compared to healthy controls (66% higher), but the difference was not statistically significant (P = 0.229). MiR-122 levels were significantly correlated with ALT (correlation coefficient [R] = 0.7, P < 0.001), AST (R = 0.71, P < 0.001), and HBV NA (R = 0.9, P < 0.001). The regression analysis indicated that the AUC of miR-122 levels in the diagnosis of CHB was 0.87, with a sensitivity of 0.8 and a specificity of 0.8.

CONCLUSION

MiR-122 can be used to distinguish healthy persons and patients with CHB infection with high sensitivity and specificity. These present findings presented that the complex and context-specific associations of miR-122 with liver diseases, suggesting that this may be a promising marker for liver injury.

Diagnostic value of circulating miRNA-122 for hepatitis B virus and/or hepatitis C virus-associated chronic viral hepatitis

Background: The liver-specific microRNA-122 (miR-122) has been demonstrated as a powerful and promising biomarker of hepatic diseases. However, the researches on the accuracy of miR122 detection in chronic viral hepatitis have been inconsistent, leading us to conduct this meta-analysis to systematically summarize the diagnostic value of circulating miR-122 in patients with hepatitis B virus (HBV) and/or hepatitis C virus (HCV)-associated chronic viral hepatitis.Methods: A comprehensive literature search (updated to January 30, 2019) in PubMed, Cochrane library, EMBASE, CNKI, Wanfang, and CQVIP databases was performed to identify eligible studies. The sensitivity (SEN), specificity (SPE), positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were pooled to explore the diagnostic performance of circulating miR-122. Subgroup and threshold effect analysis were further carried out to explore the heterogeneity.Results: Overall, 15 studies were finally included in this meta-analysis according to the exclusion and inclusion criteria. The pooled estimates indicated a moderately high diagnostic accuracy for circulating miR-122, with a sensitivity of 0.92 [95% confidence interval (CI), 0.86-0.95], a specificity of 0.84 (95% CI, 0.78-0.89), a PLR of 5.7 (95% CI, 4.7-8.1), a NLR of 0.1 (95% CI, 0.06-0.18), a DOR of 57 (95% CI 25-129), and an AUC of 0.93 (95% CI, 0.91-0.95). The subgroup analysis demonstrated that diagnostic accuracy was better for HCV-associated chronic viral hepatitis patients and non-Chinese compared with other subgroups. In addition, we found that serum might be a more promising matrix for detecting the expression of miR-122 than plasma.Conclusions: Our results demonstrated that circulating miR-122 have a relatively high diagnostic value for chronic viral hepatitis detection, especially in the patients with HCV-associated chronic viral hepatitis. However, further large cohort studies are still required to confirm our findings.

Circulating liver-specific microRNAs as noninvasive diagnostic biomarkers of hepatic diseases in human

CONTEXT

Hepatitis is an endemic disease worldwide leading to chronic and debilitating cancers. The viral agents and hepatotoxic substances lead to damage of hepatocytes and release of damage associated molecules in circulation. The lack of timely and rapid diagnosis of hepatitis results in chronic disease.

OBJECTIVE

The present review aimed to describe regulation, release and functions of microRNAs (miR) during human liver pathology and insights into their promising use as noninvasive biomarkers of hepatitis.

METHODS

Comprehensive data were collected from PubMed, ScienceDirect and the Web of Science databases utilizing the keywords "biomarkers", "microRNAs" and "hepatic diseases".

RESULTS

The miRs are readily released in the body fluids and blood during HBV/HCV associated hepatitis as well as metabolic, alcoholic, drug induced and autoimmune hepatitis. The liver-specific microRNAs including miR-122, miR-130, miR-183, miR-196, miR-209 and miR-96 are potential indicators of liver injury (mainly via apoptosis, necrosis and necroptosis) or hepatitis with their varied expression during acute/fulminant, chronic, liver fibrosis/cirrhosis and hepato-cellular carcinoma.

CONCLUSIONS

The liver-specific miRs can be used as rapid and noninvasive biomarkers of hepatitis to discern different stages of hepatitis. Blocking or stimulating pathways associated with miR regulation in liver could unveil novel therapeutic strategies in the management of liver diseases. Clinical significance Liver specific microRNAs interact with cellular proteins and signaling molecules to regulate the expression of various genes controlling biological processes. The circulatory level of liver specific microRNAs is indicator of severity of HBV and HCV infections as well as prognostic and therapeutic candidates. The expression of liver specific microRNAs is strongly associated with infectious, drug-induced, hepatotoxic, nonalcoholic steatohepatitis and nonalcoholic fatty liver diseases.

Emerging therapeutic biomarkers of autoimmune hepatitis and their impact on current and future management

Autoimmune hepatitis lacks a quantifiable biomarker that is close to its pathogenic mechanisms and that accurately reflects inflammatory activity, correlates with treatment response, and ensures inactive disease before treatment withdrawal. Areas covered: Micro-ribonucleic acids, programmed death-1 protein and its ligands, macrophage migration inhibitory factor, soluble CD163, B cell activating factor, and metabolite patterns in blood were considered the leading candidates as therapeutic biomarkers after search of PubMed from August 1981 to August 2017 using the search words 'biomarkers of autoimmune hepatitis'. Expert commentary: Each of the candidate biomarkers is close to the putative pathogenic mechanisms of autoimmune hepatitis, and each has attributes that support its potential role as a surrogate marker of inflammatory activity that can be monitored during treatment. Future studies must demonstrate the superiority of each biomarker to conventional indices of inflammatory activity and validate their correlation with treatment response and outcome. A reliable therapeutic biomarker would facilitate the individualization of current management algorithms, ensure that pathogenic mechanisms were disrupted or eliminated prior to treatment withdrawal, and reduce the frequency of relapse or unnecessary protracted therapy. The biomarker might also prove to be a target of next-generation therapies.

New serological markers for liver damage

The liver is the most important detoxification organ in the human body, and the damage to the liver will seriously affect the health of the body. Alanine transaminase (ALT) and aspartate transaminase (AST) are the most widely used clinical biochemical markers for liver injury. However, elevated serum ALT and AST levels can also occur in other diseases, which reduces their diagnostic value in liver injury. In order to diagnose liver damage more accurately, we need to find serum markers for liver injury.

Immune responses in DAA treated chronic hepatitis C patients with and without prior RG-101 dosing

Background & aims

With the introduction of DAA’s, the majority of treated chronic hepatitis C patients (CHC) achieve a viral cure. The exact mechanisms by which the virus is cleared after successful therapy, is still unknown. The aim was to assess the role of the immune system and miRNA levels in acquiring a sustained virological response after DAA treatment in CHC patients with and without prior RG-101 (antimiR-122) dosing.

Methods

In this multicenter, investigator-initiated study, 29 patients with hepatitis C virus (HCV) genotype 1 (n = 11), 3 (n = 17), or 4 (n = 1) infection were treated with sofosbuvir and daclatasvir ± ribavirin. 18 patients were previously treated with RG-101. IP-10 levels were measured by ELISA. Ex vivo HCV-specific T cell responses were quantified in IFN-γ-ELISpot assays. Plasma levels of miR-122 were measured by qPCR.

Results

All patients had an SVR12. IP-10 levels rapidly declined during treatment, but were still elevated 24 weeks after treatment as compared to healthy controls (median 53.82 and 39.4 pg/mL, p = 0.02). Functional IFN-γ HCV-specific T cell responses did not change by week 12 of follow-up (77.5 versus 125 SFU/106 PBMC, p = 0.46). At follow-up week 12, there was no difference in plasma miR-122 levels between healthy controls and patients with and without prior RG-101 dosing.

Conclusions

Our data shows that successful treatment of CHC patients with and without prior RG-101 dosing results in reduction of broad immune activation, and normalisation of miR-122 levels (EudraCT: 2014-002808-25).

Treatment-Induced Viral Cure of Hepatitis C Virus-Infected Patients Involves a Dynamic Interplay among three Important Molecular Players in Lipid Homeostasis: Circulating microRNA (miR)-24, miR-223, and Proprotein Convertase Subtilisin/Kexin Type 9

In patients with chronic hepatitis C virus (HCV) infection, viral hijacking of the host-cell biosynthetic pathways is associated with altered lipid metabolism, which contributes to disease progression and may influence antiviral response. We investigated the molecular interplay among four key regulators of lipid homeostasis [microRNA (miR)-122, miR-24, miR-223, and proprotein convertase subtilisin/kexin type 9 (PCSK9)] in HCV-infected patients (n=72) who achieved a treatment-based viral cure after interferon-based therapy with first-generation direct-acting antivirals. Real-time PCR was used to quantify microRNA plasma levels, and ELISA assays were used to determine plasma concentrations of PCSK9. We report that levels of miR-24 and miR-223 significantly increased in patients achieving sustained virologic response (SVR), whereas the levels of miR-122, a liver-specific cofactor for HCV infection, decreased in these patients. PCSK9 concentrations were significantly increased in SVRs, suggesting that PCSK9 may help impede viral infection. The modulatory effect of PCSK9 on HCV infection was also demonstrated in the context of HCV-infected Huh-7.5.1 cells employing recombinant human PCSK9 mutants. Together, these results provide insights into a novel coordinated interplay among three important molecular players in lipid homeostasis - circulating miR-24, miR-223 and PCSK9 - whose regulation is affected by HCV infection and treatment-based viral cure.

MicroRNAs in injury and repair

Organ damage and resulting pathologies often involve multiple deregulated pathways. MicroRNAs (miRNAs) are short, non-coding RNAs that regulate a multitude of genes at the post-transcriptional level. Since their discovery over two decades ago, miRNAs have been established as key players in the molecular mechanisms of mammalian biology including the maintenance of normal homeostasis and the regulation of disease pathogenesis. In recent years, there has been substantial progress in innovative techniques to measure miRNAs along with advances in targeted delivery of agents modulating their expression. This has expanded the scope of miRNAs from being important mediators of cell signaling to becoming viable quantitative biomarkers and therapeutic targets. Currently, miRNA therapeutics are in clinical trials for multiple disease areas and vast numbers of patents have been filed for miRNAs involved in various pathological states. In this review, we summarize miRNAs involved in organ injury and repair, specifically with regard to organs that are the most susceptible to injury: the liver, heart and kidney. In addition, we review the current state of knowledge on miRNA biology, miRNA biomarkers and nucleotide-based therapeutics designed to target miRNAs to prevent organ injury and promote repair.

Immune regulation in chronic hepatitis C virus infection

The immunological result of infection with Hepatitis C virus (HCV) depends on the delicate balance between a vigorous immune response that may clear the infection, but with a risk of unspecific inflammation and, or a less inflammatory response that leads to chronic infection. In general, exhaustion and impairment of cytotoxic function of HCV-specific T cells and NK cells are found in patients with chronic HCV infection. In contrast, an increase in immune regulatory functions is found primarily in form of increased IL-10 production possibly due to increased level and function of anti-inflammatory Tregs. Thus, the major immune players during chronic HCV infection are characterized by a decrease of cytotoxic function and increase of inhibitory functions. This may be an approach to diminish intrahepatic and systemic inflammation. Finally, there has been increasing awareness of regulatory functions of epigenetic changes in chronic HCV infection. A vast amount of studies have revealed the complexity of immune regulation in chronic HCV infection, but the interplay between immune regulation in virus and host remains incompletely understood. This review provides an overview of regulatory functions of HCV-specific T cells, NK cells, Tregs, IL-10, and TGF-β, as well as epigenetic changes in the setting of chronic HCV infection.

The Role of Hepatitis C Virus Core Antigen Testing in the Era of Direct Acting Antiviral Therapies: What We Can Learn from the Protease Inhibitors

Direct-acting antiviral (DAA) therapies have revolutionised the treatment of hepatitis C virus (HCV). The financial cost of DAAs however is significant, and first generation protease inhibitors (PIs) also require frequent monitoring of viral RNA levels to guide treatment. In this context, we examined the relevance of HCV antigen testing to evaluate the potential role in monitoring virological response to HCV antiviral treatment with the PI-based triple therapies, telaprevir (TVR) and boceprevir (BOC). Chronic HCV-infected individuals (n = 152) enrolled in the Irish Hepatitis C Outcomes Research Network (ICORN) study were prospectively analysed for baseline markers and the early viral kinetics associated with SVR. The sustained virological response (SVR) rates in the cohort receiving TVR and BOC were 87.3% and 73.8%, respectively. Baseline factors associated with successful outcome in TVR therapy were age (P = 0.0098), IFNL3 genotype (P = 0.0330) and viral load (P = 0.0456). RNA level at week 4 (P = 0.0068) and viral antigen negativity at week 2 (P = 0.0359) were predictive of SVR for TVR-based therapy. In BOC therapy, prior interferon treatment (P = 0.0209) and IFNL3 genotype (P = 0.0410) were baseline predictors of SVR. Evidence of viraemia based either on viral RNA or antigen at week 4 predicted SVR in these patients. Our data showed that rapid decline of HCV antigen to negative level at week 2 in TVR treatment and <0.96 log fmol/l in BOC treatment after commencement of PI triple therapy were associated with SVR. HCV antigen measurement should be considered as a potential alternative for monitoring treatment response during DAA-based regimens.

The beagle dog MicroRNA tissue atlas: identifying translatable biomarkers of organ toxicity

Background

MicroRNAs (miRNA) are varied in length, under 25 nucleotides, single-stranded noncoding RNA that regulate post-transcriptional gene expression via translational repression or mRNA degradation. Elevated levels of miRNAs can be detected in systemic circulation after tissue injury, suggesting that miRNAs are released following cellular damage. Because of their remarkable stability, ease of detection in biofluids, and tissue specific expression patterns, miRNAs have the potential to be specific biomarkers of organ injury. The identification of miRNA biomarkers requires a systematic approach: 1) determine the miRNA tissue expression profiles within a mammalian species via next generation sequencing; 2) identify enriched and/or specific miRNA expression within organs of toxicologic interest, and 3) in vivo validation with tissue-specific toxicants. While miRNA tissue expression has been reported in rodents and humans, little data exists on miRNA tissue expression in the dog, a relevant toxicology species. The generation and evaluation of the first dog miRNA tissue atlas is described here.

Results

Analysis of 16 tissues from five male beagle dogs identified 106 tissue enriched miRNAs, 60 of which were highly enriched in a single organ, and thus may serve as biomarkers of organ injury. A proof of concept study in dogs dosed with hepatotoxicants evaluated a qPCR panel of 15 tissue enriched miRNAs specific to liver, heart, skeletal muscle, pancreas, testes, and brain. Dogs with elevated serum levels of miR-122 and miR-885 had a correlative increase of alanine aminotransferase, and microscopic analysis confirmed liver damage. Other non-liver enriched miRNAs included in the screening panel were unaffected. Eli Lilly authors created a complimentary Sprague Dawely rat miRNA tissue atlas and demonstrated increased pancreas enriched miRNA levels in circulation, following caerulein administration in rat and dog.

Conclusion

The dog miRNA tissue atlas provides a resource for biomarker discovery and can be further mined with refinement of dog genome annotation. The 60 highly enriched tissue miRNAs identified within the dog miRNA tissue atlas could serve as diagnostic biomarkers and will require further validation by in vivo correlation to histopathology. Once validated, these tissue enriched miRNAs could be combined into a powerful qPCR screening panel to identify organ toxicity during early drug development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2958-x) contains supplementary material, which is available to authorized users.

Circulating Organ-Specific MicroRNAs Serve as Biomarkers in Organ-Specific Diseases: Implications for Organ Allo- and Xeno-Transplantation

Different cell types possess different miRNA expression profiles, and cell/tissue/organ-specific miRNAs (or profiles) indicate different diseases. Circulating miRNA is either actively secreted by living cells or passively released during cell death. Circulating cell/tissue/organ-specific miRNA may serve as a non-invasive biomarker for allo- or xeno-transplantation to monitor organ survival and immune rejection. In this review, we summarize the proof of concept that circulating organ-specific miRNAs serve as non-invasive biomarkers for a wide spectrum of clinical organ-specific manifestations such as liver-related disease, heart-related disease, kidney-related disease, and lung-related disease. Furthermore, we summarize how circulating organ-specific miRNAs may have advantages over conventional methods for monitoring immune rejection in organ transplantation. Finally, we discuss the implications and challenges of applying miRNA to monitor organ survival and immune rejection in allo- or xeno-transplantation.

Micro RNAs mir-106a, mir-122 and mir-197 are increased in severe acute viral hepatitis with coagulopathy

BACKGROUND & AIMS

The severity of acute viral hepatitis, which may be caused by several distinct viruses, varies among individual patients. In rare cases, severe hepatic injury with sudden loss of liver function may occur, which is clinically indicated by the occurrence of coagulopathy or encephalopathy. As the molecular mechanisms of this liver injury are largely unknown, we investigated extracellular micro RNA (miRNA) profiles in 54 patients acutely infected with one of four different hepatotropic viruses, in order to identify those miRNAs which indicate severe viral hepatitis associated with coagulopathy.

METHODS

First, the profile of miRNAs was extensively analysed using a microarray-based approach in highly characterized 24 patients, matched in terms of sex, age and level of liver enzymes, as well as in three healthy controls. The cohort included samples from 18 patients with moderate and six individuals with severe hepatitis, indicated by abnormal prothrombin time and higher alanine aminotransferase and bilirubin levels. miRNAs found to be upregulated in severe hepatitis were then quantified by real-time PCR in the expanded cohort of 54 patients.

RESULTS

Comprehensive microarray-based miRNA profiling identified upregulation of mir-106a, mir-122 and mir-197 in patients with severe acute viral hepatitis with coagulopathy, as compared to patients who did not develop coagulopathy. mir-106a, mir-122 and mir-197 were then proven to be significantly upregulated in patients with severe acute viral hepatitis by quantitative real-time PCR (P < 0.01, Mann-Whitney U-test).

CONCLUSIONS

mir-106a, mir-122 and mir-197 could be potential markers for severe acute viral hepatitis associated with coagulopathy.

MicroRNA let-7g cooperates with interferon/ribavirin to repress hepatitis C virus replication

MicroRNAs (miRNA) have been implicated in HCV infection. The present study analyzed the effects of let-7g on HCV infection in vitro, in clinical tissue and serum samples. Here, we show that the expression of let-7g in serum and liver tissue is significantly higher in patients with sustained virologic response (SVR). We show that interferon (IFN)/ribavirin (RBV) induces let-7g expression through p38/AP-1 signaling. Overexpression of let-7g reduced HCV gene or core protein level and inhibited the HCV viral load. The let-7g and IFN/RBV have additively inhibitory effect on HCV replication. These data implicate let-7g as a new therapeutic drug to additively cooperate with IFN/RBV to repress HCV replication. Key messages: let-7g expression is increased in serum and liver tissue of patients with SVR. Interferon/ribavirin induces let-7g expression through p38/AP-1 signaling. Overexpression of let-7g can repress HCV replication. Let-7g additively cooperates with interferon/ribavirin to repress HCV replication. Lin28B silencing can reverse let-7g expression and repress HCV replication.

Serum miR-122 may serve as a biomarker for response to direct acting antivirals: effect of paritaprevir/R with dasabuvir or ombitasvir on miR-122 in HCV-infected subjects

Circulating microRNAs (miRNA) have been intensely investigated as biomarkers in disease and therapy. Several studies have identified miR-122 as an important regulator of HCV replication. The effect of new therapies that directly target the HCV replication life cycle on circulating microRNA levels has not been elucidated. We performed expression profiling of circulating miRNA in serum in subjects treated with HCV direct-acting antiviral agents (DAAs). Serum miRNA levels were evaluated from two studies in HCV GT1-infected treatment-naïve subjects and prior nonresponders to pegylated interferon (pegIFN) and ribavirin (RBV) who received paritaprevir/ritonavir + dasabuvir + RBV for 12 weeks, and in treatment-naïve genotype (GT)1-3-infected subjects who received paritaprevir/ritonavir + ombitasvir ± RBV for 12 weeks. Over 100 different miRNA species were detected in serum. Of these, levels of miR-122 showed the most consistent change in response to treatment across all HCV genotypes. In all subjects, miR-122 showed an average four-fold reduction between baseline and week 2, and remained below baseline through post-treatment week 12 in subjects who achieved sustained virological response. In contrast, in subjects who did not achieve SVR, miR-122 levels began to return to baseline levels after the second week of treatment. The change in miR-122 levels was similar across genotypes, and was comparable with or without RBV. This is the first report comparing expression levels of circulating miRNA in HCV GT1-3 subjects treated with IFN-free combinations of DAAs. The results suggest that serum levels of miR-122 are reduced following treatment in subjects who achieve SVR, and correlate with HCV RNA levels across genotypes.

MicroRNAs: Role in Hepatitis C Virus pathogenesis

Hepatitis C virus (HCV) is a global health burden with an estimated 170-200 million peoples chronically infected worldwide. HCV infection remains as an independent risk factor for chronic hepatitis, liver cirrhosis, hepatocellular carcinoma, and a major reason for liver transplantation. Discovery of direct acting antiviral (DAA) drugs have shown promising results with more than 90% success rate in clearing the HCV RNA in patients, although long-term consequences remain to be evaluated. microRNAs (miRNAs) are important players in establishment of HCV infection and target crucial host cellular factors needed for productive HCV replication and augmented cell growth. Altered expression of miRNAs is involved in the pathogenesis associated with HCV infection by controlling signaling pathways such as immune response, proliferation and apoptosis. miRNA is emerging as a means of communication between various cell types inside the liver. There is likely possibility of developing circulating miRNAs as biomarkers of disease progression and can also serve as diagnostic tool with potential of early therapeutic intervention in HCV associated end stage liver disease. This review focuses on recent studies highlighting the contribution of miRNAs in HCV life cycle and their coordinated regulation in HCV mediated liver disease progression.

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.

Complex interactions between microRNAs and hepatitis B/C viruses

MicroRNAs (miRNAs) are a class of small noncoding RNAs that post-transcriptionally regulate the expression of many target genes via mRNA degradation or translation inhibition. Many studies have shown that miRNAs are involved in the modulation of gene expression and replication of hepatitis B virus (HBV) and hepatitis C virus (HCV) and play a pivotal role in host-virus interactions. Increasing evidence also demonstrates that viral infection leads to alteration of the miRNA expression profile in hepatic tissues or circulation. The deregulated miRNAs participate in hepatocellular carcinoma (HCC) initiation and progression by functioning as oncogenes or tumor suppressor genes by targeting various genes involved in cancer-related signaling pathways. The distinct expression pattern of miRNAs may be a useful marker for the diagnosis and prognosis of virus-related diseases considering the limitation of currently used biomarkers. Moreover, the role of deregulated miRNA in host-virus interactions and HCC development suggested that miRNAs may serve as therapeutic targets or as tools. In this review, we summarize the recent findings about the deregulation and the role of miRNAs during HBV/HCV infection and HCC development, and we discuss the possible mechanism of action of miRNAs in the pathogenesis of virus-related diseases. Furthermore, we discuss the potential of using miRNAs as markers for diagnosis and prognosis as well as therapeutic targets and drugs.

Predictive prognostic role of miR-181a with discrepancy in the liver and serum of genotype 4 hepatitis C virus patients

microRNA (miRNA) expression in organs does not always represent their quantity in serum. A disparity in the expression of miR-181a has been reported in the tissues and serum of hepatocellular carcinoma (HCC) patients. Since hepatitis C virus (HCV) is a major cause of HCC and miR-181a has never been studied in HCV, the present study aimed to investigate the miR-181a expression profile in genotype 4 (GT4)-HCV patients to evaluate whether this pattern is also apparent in HCV. RNA was extracted from liver tissues, peripheral mononuclear cells (PBMCs) and serum samples from GT4-HCV-infected patients and healthy donors to evaluate the relative miR-181a expression using quantitative reverse transcription-polymerase chain reaction. miR-181a was significantly higher in the serum of naïve patients compared to controls, and an inverse correlation with the viral load and liver enzymes was apparent. By contrast, no difference in miR-181a expression was observed in the liver tissues and PBMCs of patients compared to controls. This expression observed in HCV is conflicting to that previously reported in HCC. The study also demonstrates a significant upregulation of miR-181a post-interferon/ribavirin treatment in the serum of sustained virological responders (SVRs) compared to non-responders and treatment-naïve SVRs. In conclusion, miR-181a may be considered to be a possible prognostic marker in GT4-HCV infection.

Roadmap of miR-122-related clinical application from bench to bedside

INTRODUCTION

microRNA (miRNA) regulates target gene expression to influence many physiological and pathophysiological processes. The liver-specific miRNA, miR-122, contributes to liver function and plays a very important role in hepatic diseases including the viral hepatitis C (HCV). For this reason, developing an miR-122-related clinical application could be very useful in managing or treating many hepatic disorders.

AREAS COVERED

This review introduces the basic concepts of miRNA and miR-122. It also discusses the possibility of miR-122 as a biomarker and summarizes the results of anti-miR-122 treatment from basic research to a Phase IIa clinical trial. Furthermore, the authors discuss the potential opportunities and challenges found in clinical trials with miravirsen.

EXPERT OPINION

miR-122 may be a useful biomarker as both a diagnostic and prognostic tool. Furthermore, miravirsen is a novel treatment with great potential for hepatic disease treatment, especially in HCV. However, there is certainly the need for future investigations to better determine whether miR-122 is really specific for liver. It is also important to elucidate whether miR-122 is actually specific for HCV genome and further investigate the therapeutic potential of miravirsen. Only once these studies have been completed can anti-miR-122 treatment potentially enter the clinical practice.

The role of microRNAs in hepatitis C virus RNA replication

Replication of hepatitis C virus (HCV) RNA is influenced by a variety of microRNAs, with the main player being the liver-specific microRNA-122 (miR-122). Binding of miR-122 to two binding sites near the 5' end of the 5' untranslated region (UTR) of the HCV genomic RNA results in at least two different effects. On the one hand, binding of miR-122 and the resulting recruitment of protein complexes containing Argonaute (Ago) proteins appears to mask the viral RNA's 5' end and stabilizes the viral RNA against nucleolytic degradation. On the other hand, this interaction of miR-122 with the 5'-UTR also stimulates HCV RNA translation directed by the internal ribosome entry site (IRES) located downstream of the miR-122 binding sites. However, it is suspected that additional, yet undefined roles of miR-122 in HCV replication may also contribute to HCV propagation. Accordingly, miR-122 is considered to contribute to the liver tropism of the virus. Besides miR-122, let-7b, miR-196, miR-199a* and miR-448 have also been reported to interact directly with the HCV RNA. However, the latter microRNAs inhibit HCV replication, and it has been speculated that miR-199a* contributes indirectly to HCV tissue tropism, since it is mostly expressed in cells other than hepatocytes. Other microRNAs influence HCV replication indirectly. Some of those are advantageous for HCV propagation, while others suppress HCV replication. Consequently, HCV up-regulates or down-regulates, respectively, the expression of most of these miRNAs.

Differential stability of cell-free circulating microRNAs: implications for their utilization as biomarkers

Background

MicroRNAs circulating in the blood, stabilized by complexation with proteins and/or additionally by encapsulation in lipid vesicles, are currently being evaluated as biomarkers. The consequences of their differential association with lipids/vesicles for their stability and use as biomarkers are largely unexplored and are subject of the present study.

Methods

The levels of a set of selected microRNAs were determined by quantitative reverse-transcription PCR after extraction from sera or vesicle- and non-vesicle fractions prepared from sera. The stability of these microRNAs after incubation with RNase A or RNase inhibitor, an inhibitor of RNase A family enzymes was studied.

Results

The levels of microRNA-1 and microRNA-122, but not those of microRNA-16, microRNA-21 and microRNA-142-3p, declined significantly during a 5-h incubation of the sera. RNase inhibitor prevented the loss of microRNAs in serum as well as the degradation of microRNA-122, a microRNA not expressed in blood cells, in whole blood. Stabilization of microRNA-122 was also achieved by hemolysis. Prolonged incubation of the sera led to enrichment of vesicle-associated relative to non-vesicle-associated microRNAs. Vesicle-associated microRNAs were more resistant to RNase A treatment than the respective microRNAs not associated with vesicles.

Conclusions

Serum microRNAs showed differential stability upon prolonged incubation. RNase inhibitor might be useful to robustly preserve the pattern of cell-free circulating microRNAs. In the case of microRNAs not expressed in blood cells this can also be achieved by hemolysis. Vesicle-associated microRNAs appeared to be more stable than those not associated with vesicles, which might be useful to disclose additional biomarker properties of miRNAs.