miRNAs regulate immune response and signaling during hepatitis C virus infection

The Role of Epigenetic Mechanisms in the Pathogenesis of Hepatitis C Infection

Hepatitis C virus (HCV) is a hepatotropic virus that can be transmitted through unsafe medical procedures, such as injections, transfusions, and dental treatment. The infection may be self-limiting or manifest as a chronic form that induces liver fibrosis, cirrhosis, or progression into hepatocellular carcinoma (HCC). Epigenetic mechanisms are major regulators of gene expression. These mechanisms involve DNA methylation, histone modifications, and the activity of non-coding RNAs, which can enhance or suppress gene expression. Abnormal activity or the dysregulated expression of epigenetic molecules plays an important role in the pathogenesis of various pathological disorders, including inflammatory diseases and malignancies. In this review, we summarise the current evidence on epigenetic mechanisms involved in HCV infection and progression to HCC.

Novel Therapeutic Horizons: SNCA Targeting in Parkinson's Disease

Alpha-synuclein (αSyn) aggregates are the primary component of Lewy bodies, which are pathological hallmarks of Parkinson's disease (PD). The toxicity of αSyn seems to increase with its elevated expression during injury, suggesting that therapeutic approaches focused on reducing αSyn burden in neurons could be beneficial. Additionally, studies have shown higher levels of SNCA mRNA in the midbrain tissues and substantia nigra dopaminergic neurons of sporadic PD post-mortem brains compared to controls. Therefore, the regulation of SNCA expression and inhibition of αSyn synthesis could play an important role in the pathogenesis of injury, resulting in an effective treatment approach for PD. In this context, we summarized the most recent and innovative strategies proposed that exploit the targeting of SNCA to regulate translation and efficiently knock down cytoplasmatic levels of αSyn. Significant progress has been made in developing antisense technologies for treating PD in recent years, with a focus on antisense oligonucleotides and short-interfering RNAs, which achieve high specificity towards the desired target. To provide a more exhaustive picture of this research field, we also reported less common but highly innovative strategies, including small molecules, designed to specifically bind 5'-untranslated regions and, targeting secondary nucleic acid structures present in the SNCA gene, whose formation can be modulated, acting as a transcription and translation control. To fully describe the efficiency of the reported strategies, the effect of αSyn reduction on cellular viability and dopamine homeostasis was also considered.

MicroRNAs in infectious diseases: potential diagnostic biomarkers and therapeutic targets

MicroRNAs (miRNAs) are conserved, short, non-coding RNAs that play a crucial role in the post-transcriptional regulation of gene expression. They have been implicated in the pathogenesis of cancer and neurological, cardiovascular, and autoimmune diseases. Several recent studies have suggested that miRNAs are key players in regulating the differentiation, maturation, and activation of immune cells, thereby influencing the host immune response to infection. The resultant upregulation or downregulation of miRNAs from infection influences the protein expression of genes responsible for the immune response and can determine the risk of disease progression. Recently, miRNAs have been explored as diagnostic biomarkers and therapeutic targets in various infectious diseases. This review summarizes our current understanding of the role of miRNAs during viral, fungal, bacterial, and parasitic infections from a clinical perspective, including critical functional mechanisms and implications for their potential use as biomarkers and therapeutic targets.

Role of MicroRNAs in the Development of Chronic Liver Disease in Hepatitis Virus-Infected Egyptian Population

Background:  The identification of miRNAs that play a role in the regulation of the viral life cycle and its related liver illness opens the door to the development of diagnostic biomarkers that can categorize patients at higher risk for developing end-stage liver disease. This study was designed to investigate the role of miRNAs in the development of viral hepatitis-induced chronic liver disease (CLD) in the Egyptian population, as well as their potential as possible diagnostic biomarkers for chronic hepatitis virus infection. Methodology: The study involved 100 CLD patients; 55 cases of hepatitis C virus (HCV) and 45 cases of non-viral hepatitis, in addition to 40 healthy controls. The expression of five miRNAs (miR‐30, miR‐122, miR‐296, miR‐351, and miR‐431) was assessed using real-time PCR. Results: Serum levels of miR‐30, miR‐122, miR‐296, miR‐351, and miR‐431 were significantly higher in all patients than the control group (p<0.01). Also, they were significantly greater in viral hepatitis cases compared to the non-viral hepatitis group (p<0.01). The sensitivities and specificities of miR-122a, miR‐30, miR‐296, miR‐351, and miR‐431 were (85.71%, 83.33%), (82.35%, 83.33%), (85.71%, 69.44%), (88.64%, 75.76%), and (87.80%, 65.79%), respectively. Conclusions: miR‐30, miR‐122, miR‐296, miR‐351, and miR‐431 play key roles in the development of CLD as a consequence of viral infection. So, they have the potential to be targeted for the early detection of chronic hepatitis virus infection and allow for exploring a new frontier in the discovery of innovative therapeutics to combat chronic viral infection and its serious life-threatening complications including liver cancer.

Drugs of Abuse and Their Impact on Viral Pathogenesis

Commonly misused substances such as alcohol, cocaine, heroin, methamphetamine, and opioids suppress immune responses and may impact viral pathogenesis. In recent years, illicit use of opioids has fueled outbreaks of several viral pathogens, including the human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). This review focuses on the myriad of mechanisms by which drugs of abuse impact viral replication and disease progression. Virus–drug interactions can accelerate viral disease progression and lead to increased risk of virus transmission.

miRNA-Based Signature Associated With Tumor Mutational Burden in Colon Adenocarcinoma

Colon adenocarcinoma (COAD) is one of the most common malignant tumors. Tumor mutation burden (TMB) has become an independent biomarker for predicting the response to immune checkpoint inhibitors (ICIs). miRNAs play an important role in cancer-related immune regulation. However, the relationship between miRNA expression and TMB in COAD remains unclear. Therefore, the transcriptome profiling data, clinical data, mutation annotation data, and miRNA expression profiles for cases of COAD were downloaded from the TCGA database. Subsequently, 323 COAD cases were randomly divided into training and test sets. The differential expression of miRNAs in the high and low TMB groups in the training set was obtained as a signature using the least absolute shrinkage and selection operator (LASSO) logistic regression and verified in the test set. Based on the LASSO method, principal component analysis (PCA), and ROC, we found that the signature was credible because it can discriminate between high and low TMB levels. In addition, the correlation between the 18-miRNA-based signature and immune checkpoints was performed, followed by qRT-PCR, to measure the relative expression of 18 miRNAs in COAD patients. The miRNA-based model had a strong positive correlation with TMB and a weak positive correlation with CTLA4 and CD274 (PD-L1). However, no correlation was observed between the model and SNCA (PD-1). Finally, enrichment analysis of the 18 miRNAs was performed to explore their biological functions. The results demonstrated that 18 miRNAs were involved in the process of immunity and cancer pathways. In conclusion, the 18-miRNA-based signature can effectively predict and discriminate between the different TMB levels of COAD and provide a guide for its treatment with ICIs.

miRNAs as Potential Biomarkers for Viral Hepatitis B and C

Around 257 million people are living with hepatitis B virus (HBV) chronic infection and 71 million with hepatitis C virus (HCV) chronic infection. Both HBV and HCV infections can lead to liver complications such as cirrhosis and hepatocellular carcinoma (HCC). To take care of these chronically infected patients, one strategy is to diagnose the early stage of fibrosis in order to treat them as soon as possible to decrease the risk of HCC development. microRNAs (or miRNAs) are small non-coding RNAs which regulate many cellular processes in metazoans. Their expressions were frequently modulated by up- or down-regulation during fibrosis progression. In the serum of patients with HBV chronic infection (CHB), miR-122 and miR-185 expressions are increased, while miR-29, -143, -21 and miR-223 expressions are decreased during fibrosis progression. In the serum of patients with HCV chronic infection (CHC), miR-143 and miR-223 expressions are increased, while miR-122 expression is decreased during fibrosis progression. This review aims to summarize current knowledge of principal miRNAs modulation involved in fibrosis progression during chronic hepatitis B/C infections. Furthermore, we also discuss the potential use of miRNAs as non-invasive biomarkers to diagnose fibrosis with the intention of prioritizing patients with advanced fibrosis for treatment and surveillance.

Synthetic Opioid Use and Common Injection-associated Viruses: Expanding the Translational Research Agenda

The US is in the midst of a major epidemic of opioid addiction and related comorbidities. People with opioid use disorder (OUD) are at significant risk for transmission of several blood-borne pathogens including the human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). Commonly abused opioids and their receptors promote viral replication and virus-mediated pathology. However, most studies demonstrating an adverse effect of drugs of abuse have been conducted in vitro, the specific effects of synthetic opioids on viral replication have been poorly characterized, and the evaluation of opioid-virus interactions in clinically relevant populations is rare. Rigorous characterization of the interactions among synthetic opioids, host cells, and common injection-associated viral infections will require an interdisciplinary research approach and translational studies conducted on humans. Such research promises to improve clinical management paradigms for difficult-to-treat populations, facilitate rational public health policies given severely strained resources, and reveal additional pathways for novel target-specific therapeutic interventions. This mini-review examines the published literature on the effects of opioids on HIV, HBV, and HCV pathogenesis and proposes a series of scientific questions and considerations to establish a translational research agenda focused on opioid-virus interactions.

Circular RNA 4099 aggravates hydrogen peroxide-induced injury by down-regulating microRNA-706 in L02 cells

AIMS

Hepatitis is a kind of liver dysfunction and usually refers to a variety of pathogenic factors. Circular RNA (circRNA) participates in diverse diseases. This study aimed to explore the roles and regulatory mechanisms of the circRNA-4099 in L02 cell line.

MAIN METHODS

Cells were induced with H₂O₂ dilutions and transfected with circRNA-4099 overproduction vectoer and the specific siRNA (si-circRNA-4099), as well as microRNA-706 (miR-706) mimic or the corresponding controls. Cell viability was detected with the CCK-8. The apoptotic rate was determined by the annexin v-FITC/PI with flow cytometer. The expression of circRNA-4099 or miR-706 was quantified depending on qRT-PCR. The reactive oxygen species (ROS) level was examined through ROS assay. The relative proteins were individually determined via western blot. The relationship between the circRNA-4099 and miR-706 was detected through bioinformatics analysis and luciferase reporter assay.

KEY FINDINGS

H₂O₂ induced inhibition of viability and promotion of apoptosis, ROS production and cell fibrosis as well as keap1/Nrf2 and p38MAPK cascades on L02 cell line. circRNA-4099 was stimulated by H₂O₂. Plentiful circRNA-4099 augmented H₂O₂-resulted damage by inhibiting miR-706. miR-706 mimic partly abolished the influence of circRNA-4099 on L02 cells. Meanwhile, circRNA-4099 silence exerted opposite effect on these elements above.

SIGNIFICANCE

circRNA-4099 aggravated H₂O₂-induced injury by inhibiting miR-706 through triggering keap1/Nrf2 and p38MAPK in the L02 cells.

Relation between microRNA-21, transforming growth factor β and response to treatment among chronic hepatitis C patients

BACKGROUND

Persistence of hepatitis C virus (HCV) infection and response to antiviral therapy has been shown to be associated with inappropriate levels of cytokines and microRNAs (miRNAs). miRNA levels have been reported to fluctuate during treatment. Thus they could be useful predictors for responses to treatment among HCV infected patients, thereby reducing ineffective treatments.

AIM

The current study aimed to investigate the relation between miRNA-21 expression profiles, transforming growth factor β (TGF-β) serum levels and response to treatment with the new direct antiviral drugs (sofosbuvir + daclatasvir ± ribavirin), among HCV infected Egyptian patients.

SUBJECTS AND METHODS

This prospective study was conducted on 50 HCV infected patients (before and after treatment) and 20 healthy volunteers. miRNA expression profiles were determined by real-time polymerase chain reaction and TGF-β1 serum levels were measured by using enzyme-linked immunosorbent assay.

RESULTS

There was a significant increase in serum albumin, platelets count and a significant decrease in liver enzymes, serum bilirubin, and prothrombin time after treatment. Significant reduction of viral load among HCV patients after receiving the treatment was reported. Concomitantly, there was an increase in the relative quantity of miRNA-21 (P = .001*) and serum levels of TGF-β1 ( P = .337) among HCV patients after receiving treatment.

CONCLUSION

Nearly all responders to direct antiviral drugs showed increased levels of both miRNA-21 and TGF-β1. This may indicate an interplay between TGF-β1 and miRNA-21 during remission or progression of viral infection. Thus miRNA-21 could be used as promising serum biomarker, for assessment of antiviral treatment efficacy and improvement of fibrosis among chronically infected HCV patients.

Depletion of MicroRNA-373 Represses the Replication of Hepatitis C Virus via Activation of Type 1 Interferon Response by Targeting IRF5

PURPOSE

Hepatitis C virus (HCV) poses a risk of chronic liver disease and threatens a significant number of people worldwide. MicroRNAs (miRNAs) are linked to the regulation of hepatocarcinogenesis. Although miR-373 is required for HCV infection, the underlying mechanisms of miR-373 involvement in HCV replication remain elusive.

MATERIALS AND METHODS

Quantitative reverse transcription PCR assays were performed to detect the abundances of miR-373 and HCV RNA either in Huh 7.5 cells or liver biopsy specimens with HCV infection. Luciferase assay was employed to probe the interactions between miR-373 and interferon regulatory factor 5 (IRF5). Western blot was conducted to investigate the effect of miR-373 and IRF5 on HCV replication and activation of type 1 interferon (IFN) response in JFH1-infected Huh 7.5 cells.

RESULTS

HCV infection appeared to be caused by increased miR-373 expression. Addition of miR-373 promoted HCV RNA expression, while miR-373 depletion led to an inhibitive effect on HCV replication. Concordantly, IRF5, as a direct target, was limited by miR-373 in JFH1-infected Huh 7.5 cells. In addition, introduction of IRF5 protected HCV replication in the presence of abundant miR-373. Furthermore, the miR-373-mediated inhibitory effect on type 1 IFN response was ablated following IRF5 accumulation.

CONCLUSION

miR-373 abrogation reduced HCV replication via activation of type 1 IFN responses by targeting IRF5 in JFH1-infected Huh 7.5 cells, suggesting a promising therapeutic for treating HCV infection.

Interaction of miR-125b-5p with Human antigen R mRNA: Mechanism of controlling HCV replication

Cellular miRNAs influence Hepatitis C virus (HCV) infection in multiple ways. In this study, we demonstrate that miR-125b-5p is upregulated in HCV infected patient serum samples as well as in HCV infected liver carcinoma cells and is involved in translational regulation of one of its predicted targets, Human antigen R (HuR). We used miRNA mimics and antagomiRs to confirm that HuR is a bonafide miR-125b target. Previously, we have shown that HuR is a positive regulator of HCV replication, whereas we noticed that miR-125b is a negative regulator of HCV infection. As a connecting link between these two observations, we showed that knockdown of miR-125b-5p increased HuR protein levels and rescued HCV replication when the availability of HuR in the cytoplasm was compromised using siRNAs against HuR or an inhibitor of HuR export to the cytoplasm. Overall, the study sheds light on the ability of host cell to use a miRNA as a tool to control virus propagation.