Circulating miRNA profile in HCV infected serum: novel insight into pathogenesis. Sci Rep. 2013;3:1555. [PMID: 23549102 PMCID: PMC3615409 DOI: 10.1038/srep01555]

Expression of microRNAs in the detection and therapeutic roles of viral infections: Mechanisms and applications

In recent years, microRNAs (miRNAs) are potential diagnostic and therapeutic agents for viral infections. Here, we aimed to investigate the expression of microRNAs in the identification and treatment of viral infections. MiRNAs are non-coding molecules that control gene expression and participate in numerous biological processes, including host immunity and pathogen duplication. MiRNAs have played a role in the pathogenesis of various viral infections, such as HIV and HCV. Their presence in the tissues and serum of infected patients has been demonstrated to help predict disease progression, identify disease subtypes, and evaluate treatment responses. Research has shown that miRNAs can detect viral infections by identifying specific miRNAs in serum. For example, miRNA expression profiling was recently used to distinguish between hepatitis C and hepatitis B viral infections precisely. Furthermore, miRNAs can be used to detect the presence of multiple viral infections simultaneously by assessing the expression levels of these miRNAs. Also, miRNAs can differentiate between different genetic variants of the same virus, which is useful for identifying emerging viral strains or drug-resistant ones. MiRNAs have been identified as being a factor in treating viral infections. For example, miRNA mimics have decreased gene expression and halted viral replication in HIV, HCV, and EBV. Moreover, microRNA antagonists have been utilized to inhibit pro-inflammatory cytokines, thereby modulating the immune response and the severity of infections.

Identification and characterization of host miRNAs that target the mouse mammary tumour virus (MMTV) genome

The intricate interplay between viruses and hosts involves microRNAs (miRNAs) to regulate gene expression by targeting cellular/viral messenger RNAs (mRNAs). Mouse mammary tumour virus (MMTV), the aetiological agent of breast cancer and leukaemia/lymphomas in mice, provides an ideal model to explore how viral and host miRNAs interact to modulate virus replication and tumorigenesis. We previously reported dysregulation of host miRNAs in MMTV-infected mammary glands and MMTV-induced tumours, suggesting a direct interaction between MMTV and miRNAs. To explore this further, we systematically examined all potential interactions between host miRNAs and the MMTV genome using advanced prediction tools. Leveraging miRNA sequencing data from MMTV-expressing cells, we identified dysregulated miRNAs capable of targeting MMTV. Docking analysis validated the interaction of three dysregulated miRNAs with the MMTV genome, followed by confirmation with RNA immunoprecipitation assays. We further identified host targets of these miRNAs using mRNA sequencing data from MMTV-expressing cells. These findings should enhance our understanding of how MMTV replicates and interacts with the host to induce cancer in mice, a model important for cancer research. Given MMTV's potential zoonosis and association with human breast cancer/lymphomas, if confirmed, our work could further lead to novel miRNA-based antivirals/therapeutics to prevent possible MMTV transmission and associated cancers in humans.

High Serum miR-361-3p Predicts Early Postdischarge Infections after Autologous Stem Cell Transplantation

BACKGROUND

Autologous hematopoietic stem cell transplantation (AHSCT) is currently the backbone of the treatment of multiple myeloma (MM) and relapsed and refractory lymphomas. Notably, infections contribute to over 25% of fatalities among AHSCT recipients within the initial 100 days following the procedure. In this study, we aimed to evaluate three selected miRNAs: hsa-miR-155-5p, hsa-miR-320c, and hsa-miR-361-3p, in identifying AHSCT recipients at high risk of infectious events up to 100 days post-transplantation after discharge.

MATERIALS AND METHODS

The study group consisted of 58 patients (43 with MM, 15 with lymphoma) treated with AHSCT. Blood samples were collected from all patients at the same time point: on day +14 after transplantation.

RESULTS

Fifteen patients (25.9%) experienced infectious complications after post-transplant discharge within the initial +100 days post-transplantation. The median time to infection onset was 44 days (interquartile range, 25-78). Four patients required hospitalization due to severe infection. High expression of hsa-miR-361-3p (fold change [FC], 1.79; P=0.0139) in the patients experiencing infectious complications and overexpression of hsa-miR-320c (FC, 2.14; P<0.0001) in patients requiring hospitalization were observed. In the multivariate model, both lymphoma diagnosis (odds ratio [OR], 6.88; 95% confidence interval [CI], 1.55-30.56; P=0.0112) and high expression of hsa-miR-361-3p (OR, 3.00; 95% CI, 1.40-6.41; P=0.0047) were independent factors associated with post-discharge infectious complications occurrence. Our model in 10-fold cross-validation preserved its diagnostic potential with an area under the receiver operating characteristic curve of 0.78 (95% CI, 0.64-0.92).

CONCLUSION

Elevated serum hsa-miR-361-3p emerges as a promising biomarker for identifying patients at risk of infection during the early post-discharge period, potentially offering optimization of the prophylactic use of antimicrobial agents tailored to the specific risk profile of each AHSCT recipient.

Circulating microRNAs as potential biomarkers of physical activity in geriatric patients with HCV

BACKGROUND

Circulating microRNAs have been implicated in a diverse array of biological and pathological phenomena. Their potential utility as noninvasive biomarkers for screening and diagnosing various diseases has been proposed.

OBJECTIVE

This study aimed to explore the potential role of the miRNAs miR-122 and miR-486 as molecular biomarkers in the pathogenesis of hepatitis C virus (HCV) infection. Thus, miR-122 and miR-486 were detected in the serum of HCV patients and healthy controls. Moreover, the potential correlations of miR-122 and miR-486 with viral complications, such as physical activity, pain, muscle fatigue, and HCV infection, were identified.

METHODS

A total of 150 subjects aged 30 to 66 years were included in this study. The patients were classified as patients with chronic hepatitis C virus (CHC) (n = 110) or healthy controls (n = 40). Real-time polymerase chain reaction (PCR) analyses were performed to determine miR-122 and miR-486 expression. Physical activity (PA), pain score, HCV genotyping, viral overload, aspartate transaminase (AST), alanine transaminase (ALT), lactic acid dehydrogenase (LDH), creatine kinase (CK), and antioxidant status were also estimated by using prevalidated questionnaires, PCR, and spectrophotometric analyses.

RESULTS

Compared with those in normal controls, significant increases in the serum levels of miR-122 and miR-486 were reported in patients with CHC. In physically active CHC patients, there was a significant correlation between the expression of miRNAs and increased alanine transaminase (ALT), aspartate transaminase (AST), fibrosis scores, and inflammation activity, but no association was reported for hepatitis C virus (HCV) RNA or viral load. Additionally, significant decreases in LDH, CK, GSSG, and pain scores and increases in TAC, GSH, and the GSH/GSSG ratio were reported. Moreover, the expression of miR-122 and miR-486 was positively correlated with changes in body mass index (BMI) and liver fibrosis stage, as well as negatively correlated with sex, PA, TAC, GSH, GSSG, and the GSH/GSSG ratio.

CONCLUSION

MiR-122 and miR-486 expression levels were strongly correlated with physical activity, pain perception, and muscle fatigue biomarkers in HCV-infected patients. These miRNA levels were associated with elevated AST, ALT, fibrosis scores, LDH, CK, and antioxidant status, thus suggesting their potential as biomarkers for disease severity and oxidative stress. However, no correlation was observed with viral load or HCV-RNA expression, thus implying that these miRNAs may impact disease progression and symptoms through host factors, rather than directly affecting viral replication. In summary, the results demonstrated that molecular studies of miR-22 and miR-468 and their associations with PA, pain, adiposity, sex differences, and muscle fatigue, as well as routine biomarkers, could be useful as prognostic nanoninvasive biomarkers, thus providing novel therapeutic targets for CHC infection.

Regulatory role of miRNAs in the human immune and inflammatory response during the infection of SARS-CoV-2 and other respiratory viruses: A comprehensive review

miRNAs are single-stranded ncRNAs that act as regulators of different human body processes. Several miRNAs have been noted to control the human immune and inflammatory response during severe acute respiratory infection syndrome (SARS-CoV-2) infection. Similarly, many miRNAs were upregulated and downregulated during different respiratory virus infections. Here, an attempt has been made to capture the regulatory role of miRNAs in the human immune and inflammatory response during the infection of SARS-CoV-2 and other respiratory viruses. Firstly, the role of miRNAs has been depicted in the human immune and inflammatory response during the infection of SARS-CoV-2. In this direction, several significant points have been discussed about SARS-CoV-2 infection, such as the role of miRNAs in human innate immune response; miRNAs and its regulation of granulocytes; the role of miRNAs in macrophage activation and polarisation; miRNAs and neutrophil extracellular trap formation; miRNA-related inflammatory response; and miRNAs association in adaptive immunity. Secondly, the miRNAs landscape has been depicted during human respiratory virus infections such as human coronavirus, respiratory syncytial virus, influenza virus, rhinovirus, and human metapneumovirus. The article will provide more understanding of the miRNA-controlled mechanism of the immune and inflammatory response during COVID-19, which will help more therapeutics discoveries to fight against the future pandemic.

Recent Advances in Drug Discovery Toxicology

Major advances in scientific discovery and insights that stem from the development and use of new techniques and models can bring remarkable progress to conventional toxicology. Although animal testing is still considered as the "gold standard" in traditional toxicity testing, there is a necessity for shift from animal testing to alternative methods regarding the drug safety testing owing to the emerging state-of-art techniques and the proposal of 3Rs (replace, reduce, and refine) towards animal welfare. This review describes some recent research methods in drug discovery toxicology, including in vitro cell and organ-on-a-chip, imaging systems, model organisms (C. elegans, Danio rerio, and Drosophila melanogaster), and toxicogenomics in modern toxicology testing.

Specific Plasma MicroRNA Signatures Underlying the Clinical Outcomes of Hepatitis E Virus Infection

The pathogenic mechanisms determining the diverse clinical outcomes of HEV infection (e.g., self-limiting versus chronic or symptomatic versus asymptomatic) are not yet understood. Because specific microRNA signatures during viral infection inform the cellular processes involved in virus replication and pathogenesis, we investigated plasma microRNA profiles in 44 subjects, including patients with symptomatic acute (AHE, n = 7) and chronic (CHE, n = 6) hepatitis E, blood donors with asymptomatic infection (HEV BDs, n = 9), and anti-HEV IgG+ IgM- (exposed BDs, n = 10) and anti-HEV IgG- IgM- (naive BDs, n = 12) healthy blood donors. By measuring the abundance of 179 microRNAs in AHE patients and naive BDs by reverse transcription-quantitative PCR (RT-qPCR), we identified 51 potential HEV-regulated microRNAs (P value adjusted for multiple testing by the Benjamini-Hochberg correction [PBH] < 0.05). Further analysis showed that HEV genotype 3 infection is associated with miR-122, miR-194, miR-885, and miR-30a upregulation and miR-221, miR-223, and miR-27a downregulation. AHE patients showed significantly higher levels of miR-122 and miR-194 and lower levels of miR-221, miR-27a, and miR-335 than HEV BDs. This specific microRNA signature in AHE could promote virus replication and reduce antiviral immune responses, contributing to the development of clinical symptoms. We found that miR-194, miR-335, and miR-221 can discriminate between asymptomatic HEV infections and those developing acute symptoms, whereas miR-335 correctly classifies AHE and CHE patients. Our data suggest that diverse outcomes of HEV infection result from different HEV-induced microRNA dysregulations. The specific microRNA signatures described offer novel information that may serve to develop biomarkers of HEV infection outcomes and improve our understanding of HEV pathogenesis, which may facilitate the identification of antiviral targets. IMPORTANCE There is increasing evidence that viruses dysregulate the expression and/or secretion of microRNAs to promote viral replication, immune evasion, and pathogenesis. In this study, we evaluated the change in microRNA abundance in patients with acute or chronic HEV infection and asymptomatic HEV-infected blood donors. Our results suggest that different HEV-induced microRNA dysregulations may contribute to the diverse clinical manifestations of HEV infection. The specific microRNA signatures identified in this study hold potential as predictive markers of HEV infection outcomes, which would improve the clinical management of hepatitis E patients, particularly of those developing severe symptoms or chronic infections. Furthermore, this study provides new insights into HEV pathogenesis that may serve to identify antiviral targets, which would have a major impact because no effective treatments are yet available.

SQSTM1/p62 promotes miR-198 loading into extracellular vesicles and its autophagy-related secretion

MicroRNA dysregulation is a hallmark of hepatocellular carcinoma (HCC), leading to tumor growth and metastasis. Previous screening on patient specimens identified miR-198 as the most downregulated miRNA in HCC. Here, we show that miR-198 compensation leads to self-release into extracellular vesicles (EVs). Importantly, the vesicular secretion is mediated by autophagy-related pathway, initiated by sequestration of p62/miR-198 complexes in autophagosome-associated vesicle fractions. miR-198 is selectively recognized and loaded by p62 into autophagosomal fractions, whereas mutated miR-198 forms neither induce autophagy and nor interact with p62. Gain and loss of function experiments, using a CRIPR/Cas knockout (KO) and transgenic site-specific p62 mutants, identified p62 as an essential repressor of cellular miR-198 abundancy. Notably, EVs, harboring miR-198/p62 protein complexes, can be uptaken by cells in the close vicinity, leading to change of gene expression in recipient cells. In conclusion, miR-198 enhances autophagy; conversely autophagic protein p62 reduces the miR-198 levels by sorting into extracellular space.

Roles of microRNAs in Hepatitis C Virus Replication and Pathogenesis

Hepatitis C virus (HCV) infection is associated with the development of chronic liver diseases, e.g., fibrosis, cirrhosis, even hepatocellular carcinoma, and/or extra-hepatic diseases such as diabetes. As an obligatory intracellular pathogen, HCV absolutely relies on host cells to propagate and is able to modulate host cellular factors in favor of its replication. Indeed, lots of cellular factors, including microRNAs (miRNAs), have been identified to be dysregulated during HCV infection. MiRNAs are small noncoding RNAs that regulate protein synthesis of their targeting mRNAs at the post-transcriptional level, usually by suppressing their target gene expression. The miRNAs dysregulated during HCV infection could directly or indirectly modulate HCV replication and/or induce liver diseases. Regulatory mechanisms of various miRNAs in HCV replication and pathogenesis have been characterized. Some dysregulated miRNAs have been considered as the biomarkers for the detection of HCV infection and/or HCV-related diseases. In this review, we intend to briefly summarize the identified miRNAs functioning at HCV replication and pathogenesis, focusing on the recent developments.

Differentially expressed plasmatic microRNAs in Brazilian patients with Coronavirus disease 2019 (COVID-19): preliminary results

BACKGROUND

Coronavirus disease 2019 (COVID-19) is caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is known that host microRNAs (miRNAs) can be modulated to favor viral infection or to protect the host. Herein, we report preliminary results of a study aiming at identifying differentially expressed plasmatic miRNAs in Brazilian patients with COVID-19.

METHODS AND RESULTS

miRNAs were extracted from the plasma of eight patients with COVID-19 (four patients with mild COVID-19 and four patients with severe/critical COVID-19) and four healthy controls. Patients and controls were matched for sex and age. miRNA expression levels were detected using high-throughput sequencing. Differential miRNA expression and enrichment analyses were further evaluated. A total of 18 miRNAs were differentially expressed between patients with COVID-19 and controls. miR-4433b-5p, miR-6780b-3p, miR-6883-3p, miR-320b, miR-7111-3p, miR-4755-3p, miR-320c, and miR-6511a-3p were the most important miRNAs significantly involved in the PI3K/AKT, Wnt/β-catenin, and STAT3 signaling pathways. Moreover, 42 miRNAs were differentially expressed between severe/critical and mild patients with COVID-19. miR-451a, miR-101-3p, miR-185-5p, miR-30d-5p, miR-25-3p, miR-342-3p, miR-30e-5p, miR-150-5p, miR-15b-5p, and miR-29c-3p were the most important miRNAs significantly involved in the Wnt/β-catenin, NF-κβ, and STAT3 signaling pathways.

CONCLUSIONS

If validated by quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) in a larger number of participants, the miRNAs identified in this study might be used as possible biomarkers for the diagnosis and severity of COVID-19.

Implication of miR-122, miR-483, and miR-335 Expression Levels as Potential Signatures in HCV-Related Hepatocellular Carcinoma (HCC) in Egyptian Patients

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related deaths worldwide with chronic hepatitis C virus (HCV) infection as a major risk factor of HCC. Circulating microRNAs are deregulated in HCC and are candidate biomarkers. The aim of this study was to explore the expression profile of miRNA-122, miR-483, and miR-335 in the serum of HCV-related hepatocellular carcinoma (HCC). 90 HCV-related hepatocellular carcinoma (HCC) patients, 90 non-malignant HCV patients, and 60 healthy controls were included. Serum microRNAs were measured by a qRT-PCR custom array. The expression levels of miR-122 and miR-483 were upregulated in HCC patients, while the miR-335 expression level was downregulated versus controls and HCV groups. Receiver-operating characteristic (ROC) curve analysis was created to examine miRNAs. miR-483 presented the best diagnostic potential because it showed the highest diagnostic accuracy for distinguishing HCV-related HCC patients from controls (AUC = 0.98) with 100% sensitivity. Moreover, there was obvious prognostic power in distinguishing HCV from HCC (AUC = 0.95) with 88% sensitivity. In conclusion, studied microRNAs (miR-122, miR-483, and miR-335) could serve as potential non-invasive early diagnostic biomarkers for HCC, and we identified a panel of three serum microRNAs with high accuracy in HCC diagnosis. Additional studies are required to confirm this panel and test its prognostic significance.

Emerging role and function of miR-198 in human health and diseases

Ever since their discovery, microRNAs (miRNAs/miRs) have astonished us by the plethora of processes they regulate, and thus adding another dimension to the gene regulation. They have been implicated in several diseases affecting cardiovascular, neurodegenerative, hepatic, autoimmune and inflammatory functions. A primate specific exonic miRNA, miR-198 has been vastly studied during the past decade, and shown to have a critical role in wound healing. The aberrant expression of miR-198 was first reported in schizophrenia, linking it to neural development. Later, its dysregulation and tumor suppressive role was reported in hepatocellular carcinoma. However, this was just a beginning, and after which there was an explosion of reports linking miR-198 deregulation to cancers and other ailments. The first target to be identified for miR-198 was Cyclin T1 in monocytes affecting HIV1 replication. Depending on the type of cancer, miR-198 has been shown to function either as a tumor suppressor or an oncomir. Interestingly, miR-198 is not only known to regulate multiple targets and pathways, but also is itself regulated by several circular RNAs and long-non-coding RNAs, highlighting a complex regulatory network. This review highlights the currently understood mechanism and regulation of miR-198 in different diseases, and its possible diagnostic and therapeutic potential.

MicroRNA Expression Profiling in Diabetic Kidney Disease

The microRNAs (miRNAs) that can regulate diabetic kidney disease (DKD) have not been fully characterized. The aim of this study was to identify the miRNAs that affect DKD and could be used as specific biomarkers or therapeutic agents. First, kidney tissues from two DKD mouse models and control mice were screened for differences in miRNA expression by microarray analysis followed by quantitative real-time reverse transcription-PCR. Six miRNAs were differentially expressed from controls in both DKD mouse models. Among them, miRNA-125b-5p and miRNA-181b-5p were exclusively downregulated in the DKD mouse model. Next, we administered miRNA-181b-5p-mimic to DKD mice, which reduced the albuminuria and abnormal mesangial expansion. Pathway analysis and database research revealed that overexpression of miRNA-181b-5p significantly altered the expression of seven mRNAs in six known signaling pathways in the kidneys of DKD mice. Furthermore, the serum level of miRNA-125b-5p was significantly higher in patients with DKD (1.89±0.40-fold, P<0.05) compared with patients with other kidney diseases (0.94±0.13-fold) and healthy subjects (1.00±0.19-fold). Serum levels of miRNA-181b-5p were lower in patients with DKD (0.30±0.06-fold, P<0.05) compared with patients with other kidney diseases (1.06±0.20-fold) and healthy subjects (1.00±0.16-fold). These results suggest that miRNA-125b-5p and miRNA-181b-5p may represent novel diagnostic biomarkers and that miRNA-181b-5p may represent a therapeutic target for DKD.

Downregulation of hepatitis C virus replication by miR-196a using lentiviral vectors

Hepatitis C virus (HCV) is a positive-sense, single-stranded RNA virus that causes chronic hepatitis and hepatocellular carcinoma. Cellular microRNAs (miRNAs) directly modulate the viral infectivity and indirectly through targeting virus-related host factors. They play an essential role in the progression of different stages of HCV infection. The roles of miR-196 family in HCV infection and hepatocellular carcinoma progression remain poorly understood. Using ViTa databases, miR-196a as a high-score miRNA targeting the NS₅ A region of HCV genome was selected. Using dual luciferase assay and an established cell-cultured HCV (HCVcc) system, the effect of miR-196a on HCV genome was assessed. In silico analysis demonstrated the significant role of miR-196a in the downregulation of HCV replication. Using dual luciferase assay, the liver-specific miR-196a and NS₅ A gene binding was confirmed. To assess the experimental role of miR-196a, an HCVcc system was established in the Huh 7.5 cell lines. The HCV-RNA 1b derived from an infected patient was transfected into Huh 7.5 cells containing miR-196a lentiviral vectors (Huh 7.5/miR-196a), mocks (Huh 7.5/mock vector), and naïve Huh 7.5 cells. The rate of reduction of the HCV genome replication was assessed using relative real-time PCR assay. These results represent miR-196a overexpression and its roles in regulating HCV genome replication. However, miR-196a may inhibit HCV replication and accelerate the early stages of apoptosis. Overexpression of miR-196a in Huh 7.5 replicon cell is a potential new strategy to prevent hepatitis C infection. The results of this study suggest that miR-196a directly downregulates HCV replication and may serve as a new antiviral therapy.

Expression profiling of miRNA-196a biomarker in naïve hepatitis C virus-infected and Sofosbuvir plus Daclatasvir-treated patients

Micro-RNA (miRNA) is a short stretch of nucleotides that can regulate many genes associated with the various stages of the hepatitis C virus (HCV) life cycle and disease progression. This study evaluates the expression profiling of miRNA-196a in naïve HCV-infected, and Sofosbuvir plus Daclatasvir-treated patients. MiRNA-196a can inhibit HCV replication by silencing the HCV NS5A protein or downregulating the human BACH-I mRNA. The expression level of miRNA-196a was determined by quantitative reverse transcription PCR (RT-qPCR) using the whole RNA extracted from the recruited participant's serum. Results showed a 0.83-fold decrease in the miRNA-196a level in naïve HCV-infected than controls. On the contrary, an increase in the expression level by 0.06-fold was observed in Sofosbuvir plus Daclatasvir-treated patients. A negative but significant correlation was recorded between the HCV-RNA load and miRNA-196a expression level in the naïve-infected patients. Serum miRNA-196a ROC curve analysis revealed an area under the curve of 0.8278 (95% CI 0.7033-0.9524, p < 0.0001) with 82.05% sensitivity and 76.19% specificity in discriminating the healthy controls from the HCV-infected samples. In conclusion, our study explored the comparative expression levels of miRNA-196a in HCV-infected and Sofosbuvir plus Daclatasvir patients. Further studies are needed to examine the possible role of miR-196a as a therapeutic agent for treating HCV-infected patients.

Inhibition of mitochondrial complex II in neuronal cells triggers unique pathways culminating in autophagy with implications for neurodegeneration

Mitochondrial dysfunction and neurodegeneration underlie movement disorders such as Parkinson’s disease, Huntington’s disease and Manganism among others. As a corollary, inhibition of mitochondrial complex I (CI) and complex II (CII) by toxins 1-methyl-4-phenylpyridinium (MPP⁺) and 3-nitropropionic acid (3-NPA) respectively, induced degenerative changes noted in such neurodegenerative diseases. We aimed to unravel the down-stream pathways associated with CII inhibition and compared with CI inhibition and the Manganese (Mn) neurotoxicity. Genome-wide transcriptomics of N27 neuronal cells exposed to 3-NPA, compared with MPP⁺ and Mn revealed varied transcriptomic profile. Along with mitochondrial and synaptic pathways, Autophagy was the predominant pathway differentially regulated in the 3-NPA model with implications for neuronal survival. This pathway was unique to 3-NPA, as substantiated by in silico modelling of the three toxins. Morphological and biochemical validation of autophagy markers in the cell model of 3-NPA revealed incomplete autophagy mediated by mechanistic Target of Rapamycin Complex 2 (mTORC2) pathway. Interestingly, Brain Derived Neurotrophic Factor (BDNF), which was elevated in the 3-NPA model could confer neuroprotection against 3-NPA. We propose that, different downstream events are activated upon neurotoxin-dependent CII inhibition compared to other neurotoxins, with implications for movement disorders and regulation of autophagy could potentially offer neuroprotection.

Differential genes expression analysis of invasive aspergillosis: a bioinformatics study based on mRNA/microRNA

Invasive aspergillosis is a severe opportunistic infection with high mortality in immunocompromised patients. Recently, the roles of microRNAs have been taken into consideration in the immune system and inflammatory responses. Using bioinformatics approaches, we aimed to study the microRNAs related to invasive aspergillosis to understand the molecular pathways involved in the disease pathogenesis. Data were extracted from the gene expression omnibus (GEO) database. We proposed 3 differentially expressed genes; S100B, TDRD9 and TMTC1 related to pathogenesis of invasive aspergillosis. Using miRWalk 2.0 predictive tool, microRNAs that targeted the selected genes were identified. The roles of microRNAs were investigated by microRNA target prediction and molecular pathways analysis. The significance of combined expression changes in selected genes was analyzed by ROC curves study. Thirty-three microRNAs were identified as the common regulator of S100B, TDRD9 and TMTC1 genes. Several of them were previously reported in the pathogenesis of fungal infections including miR-132. Predicted microRNAs were involved in innate immune response as well as toll-like receptor signaling. Most of the microRNAs were also linked to platelet activation. The ROC chart in the combination mode of S100B/TMTC1, showed the sensitivity of 95.65 percent and the specificity of 69.23 percent. New approaches are needed for rapid and accurate detection of invasive aspergillosis. Given the pivotal signaling pathways involved, predicted microRNAs can be considered as the potential candidates of the disease diagnosis. Further investigation of the microRNAs expression changes and related pathways would lead to identifying the effective biomarkers for IA detection.

Circulating microRNAs associated with liver fibrosis in chronic hepatitis C patients

A major challenge in hepatitis C research is the detection of early potential for progressive liver disease. MicroRNAs (miRNAs) are small RNAs that regulate gene expression and can be biomarkers of pathological processes. In this study, we compared circulating miRNAs identified in hepatitis C virus (HCV)-infected patients presenting two extremes of liver disease: mild/moderate fibrosis and cirrhosis. The patients in the cirrhosis group subsequently developed hepatocellular carcinoma (HCC). We identified 163 mature miRNAs in the mild/moderate fibrosis group and 171 in the cirrhosis group, with 144 in common to both groups. Differential expression analysis revealed 5 upregulated miRNAs and 2 downregulated miRNAs in the cirrhosis group relative to the mild/moderate fibrosis group. Functional analyses of regulatory networks (target gene and miRNA) identified gene categories involved in cell cycle biological processes and metabolic pathways related to cell cycle, cancer, and apoptosis. These results suggest that the differentially expressed circulating miRNAs observed in this work (miR-215-5p, miR-483-5p, miR-193b-3p, miR-34a-5p, miR-885-5p, miR-26b-5p and miR -197-3p) may be candidates for biomarkers in the prognosis of liver disease.

High-Throughput RNA Sequencing Analysis of Plasma Samples Reveals Circulating microRNA Signatures with Biomarker Potential in Dengue Disease Progression

The circulating microRNA (miRNA) profile has been widely used for identifying potential biomarkers against viral infections. However, data on circulating microRNA expression patterns in dengue patients are scanty. Considering the impact of severity caused by dengue infection, circulating miRNA profiles in plasma of dengue patients may prove to be valuable for developing early prognostic markers for the disease severity. Here, we described an in-depth analytical study of small RNA sequencing data obtained from the plasma of 39 dengue patients. Integrating bioinformatics and in vitro studies, we identified differentially expressed miRNAs (DEMs) (log2 fold change ≥1.5, P < 0.05) associated with dengue disease progression. In comparing miRNA expression pattern with the follow-up samples, nine miRNAs were found to exhibit an altered expression that could distinguish between severe dengue and the convalescent patients. To understand the abundance and specificity of the DEMs in the context of dengue infection and disease progression, eight top-hit DEMs were further validated in the dengue virus-infected cell lines as well as in the patient's plasma and peripheral blood mononuclear cells (PBMCs) using the quantitative reverse transcription-PCR (qRT-PCR) method. Importantly, receiver operating curve analysis further confirmed that the plasma expression pattern of hsa-miR-122-5p could differentiate between different stages of dengue infection (area under the concentration-time curve [AUC] = 0.792), and dengue-negative patients with other febrile illnesses (AUC = 0.984). The in silico analysis of DEM target genes suggested an enrichment of the pathways associated with metabolism and inflammation. Our study gives a global view of miRNA expression in the plasma from dengue patients and provides a precious resource of candidate miRNAs involved in dengue infection and disease progression.IMPORTANCE Dengue virus (DENV) infection usually causes dengue fever (DF) with flu-like illness affecting infants, young children, and adults. The DF occasionally evolves into a potentially lethal complication called dengue severe (DS) leading to a rapid fall in platelet count along with plasma leakage, fluid accumulation, respiratory distress, and severe bleeding. The diverse clinical spectrum of dengue disease, as well as its significant similarity to other febrile viral illnesses, makes early identification more challenging in this high-risk group. microRNAs (miRNAs) are small (∼19 to 21 nucleotides [nt] in length), noncoding RNAs, extremely stable and easily detectable in the plasma; thus, they have potential as biomarkers for diagnosing and monitoring human diseases. This study provides a comprehensive analysis of miRNAs circulating in plasma of dengue virus-infected patients and identifies the miRNA signatures that have biomarker potential for dengue infection and disease progression.

MicroRNA Involvement in Signaling Pathways During Viral Infection

The study of miRNAs started in 1993, when Lee et al. observed their involvement in the downregulation of a crucial protein known as LIN-14 in the nematode Caenorhabditis elegans. Since then, great progress has been made regarding research on microRNAs, which are now known to be involved in the regulation of various physiological and pathological processes in both animals and humans. One such example is represented by their interaction with various signaling pathways during viral infections. It has been observed that these pathogens can induce the up-/downregulation of various host miRNAs in order to elude the host's immune system. In contrast, some miRNAs studied could have an antiviral effect, enabling the defense mechanisms to fight the infection or, at the very least, they could induce the pathogen to enter a latent state. At the same time, some viruses encode their own miRNAs, which could further modulate the host's signaling pathways, thus favoring the survival and replication of the virus. The goal of this extensive literature review was to present how miRNAs are involved in the regulation of various signaling pathways in some of the most important and well-studied human viral infections. Further on, knowing which miRNAs are involved in various viral infections and what role they play could aid in the development of antiviral therapeutic agents for certain diseases that do not have a definitive cure in the present. The clinical applications of miRNAs are extremely important, as miRNAs targeted inhibition may have substantial therapeutic impact. Inhibition of miRNAs can be achieved through many different methods, but chemically modified antisense oligonucleotides have shown the most prominent effects. Though scientists are far from completely understanding all the molecular mechanisms behind the complex cross-talks between miRNA pathways and viral infections, the general knowledge is increasing on the different roles played by miRNAs during viral infections.

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.

Exosomal MicroRNAs Associate With Neuropsychological Performance in Individuals With HIV Infection on Antiretroviral Therapy

BACKGROUND

Neurocognitive dysfunction remains prevalent among people living with HIV (PLWH), even after viral suppression on combination antiretroviral therapy (cART). We investigated associations between neuropsychological performance (NP) and patterns of circulating exosomal microRNA (exo-miRNA) expression in PLWH on cART.

SETTING

A cross-sectional examination of plasma exo-miRNA among PLWH on cART with systemic viral suppression and volunteers without HIV infection.

METHODS

Thirty-one PLWH who started cART during early infection (n = 19) or chronic infection (n = 12) participated in phlebotomy and an 11-test neuropsychological battery after >1 year on treatment. NP higher- or lower-performing participants were categorized based on normalized neuropsychological scores. Total RNA was extracted from purified exosomes of 31 PLWH and 5 volunteers without HIV and subject to small RNA sequencing. Differential expression of exo-miRNAs was examined and biological functions were predicted.

RESULTS

Eleven exo-miRNAs were up-regulated in NP lower-performing (n = 18) relative to higher-performing PLWH (n = 13). A high proportion of the differentiating exo-miRNA target the axon guidance KEGG pathway and neurotrophin tyrosine receptor kinase signaling Gene Ontology pathway. Differential expression analysis of exo-miRNAs between NP lower- (n = 7) and higher-performing (n = 12) PLWH within the early infection group alone confirmed largely consistent findings.

CONCLUSIONS

Plasma exo-miRNA content differed between NP higher- and lower-performing PLWH. Several differentially expressed exo-miRNAs were predicted to be involved in inflammation and neurodegeneration pathways. Exo-miRNA in plasma may indicate cross-talk between the circulation and central nervous system and thus may be clinically relevant for neurocognitive dysfunction in PLWH.

lncRNA HULC facilitates efficient loading of HCV-core protein onto lipid droplets and subsequent virus-particle release

The cellular lipid pool plays a central role in hepatitis C virus (HCV) life cycle, from establishing infection to virus propagation. Here, we show that a liver abundant long noncoding RNA, highly upregulated in liver carcinoma (HULC), is upregulated during HCV infection and manipulates the lipid pool to favour virus life cycle. Interestingly, HULC was found to be crucial for the increase in number of lipid droplets in infected cells. This effect was attributed to the role of HULC in lipid biogenesis. Further, we demonstrated that HULC knockdown decreases the association of HCV-core protein with lipid droplets. This exhibited a direct consequence on the release of HCV particles. The role of HULC in HCV-particle release was further substantiated by additional knockdown and mutation experiments. Additionally, we found that increased level of HULC in HCV-infected cells was a result of Retinoid X Receptor Alpha (RXRA)-mediated transcription, which seemed to be aided by HCV-core protein. Taken together, the results identify a distinct role of long noncoding RNA HULC in lipid dynamics during HCV infection, which provides new insights into the complex process of HCV propagation and pathogenesis.

Identification of potential diagnostic biomarkers for pneumonia caused by adenovirus infection in children by screening serum exosomal microRNAs

Human adenovirus (HAdV) infection causes serious pneumonia in children, leading to significant morbidity and mortality rates. However, diagnostic biomarkers for HAdV‑associated pneumonia are unavailable. Serum microRNAs (miRNAs/miRs) have been recently reported as diagnostic biomarkers for several diseases. The present study performed microRNA sequencing to identify potential biomarkers among serum exosomal miRNAs, with the aim of identifying candidate biomarkers for the diagnosis of pneumonia in adenovirus‑infected children. To validate the biomarker candidates, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was performed to determine the relative expression levels of miRNAs. As there is no endogenous reference RNA for serum miRNAs, pairwise analysis of RT‑qPCR was used in the present study to narrow down the number of biomarker candidates among all the serum exosomal miRNAs to a set of four miRNAs. As a result, the identified miRNAs (namely, miR‑450a‑5p‑miR‑103a‑3p and miR‑103b‑5p‑miR‑98‑5p) from 59 samples were considered as potential diagnostic biomarkers in adenovirus‑infected children. The results indicated that this four miRNA set could distinguish adenovirus‑infected patients from healthy controls. In conclusion, the four exosomal miRNAs identified in the present study could be considered as candidate diagnostic biomarkers for pneumonia in adenovirus‑infected children.

microRNAs: Key players in virus-associated hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is known as one of the major health problems worldwide. Pathological analysis indicated that a variety of risk factors including genetical (i.e., alteration of tumor suppressors and oncogenes) and environmental factors (i.e., viruses) are involved in beginning and development of HCC. The understanding of these risk factors could guide scientists and clinicians to design effective therapeutic options in HCC treatment. Various viruses such as hepatitis B virus (HBV) and hepatitis C virus (HCV) via targeting several cellular and molecular pathways involved in HCC pathogenesis. Among various cellular and molecular targets, microRNAs (miRNAs) have appeared as key players in HCC progression. miRNAs are short noncoding RNAs which could play important roles as oncogenes or tumor suppressors in several malignancies such as HCC. Deregulation of many miRNAs (i.e., miR-222, miR-25, miR-92a, miR-1, let-7f, and miR-21) could be associated with different stages of HCC. Besides miRNAs, exosomes are other particles which are involved in HCC pathogenesis via targeting different cargos, such as DNAs, RNAs, miRNAs, and proteins. In this review, we summarize the current knowledge of the role of miRNAs and exosomes as important players in HCC pathogenesis. Moreover, we highlighted HCV- and HBV-related miRNAs which led to HCC progression.

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.

Interference with lactate metabolism by mmu-miR-320-3p via negatively regulating GLUT3 signaling in mouse Sertoli cells

Disruption of the nursery function in Sertoli cells (SCs) by reducing lactate production, a preferred energy substrate for developed germ cells (spermatocytes and spermatids), is tightly associated with spermatogenic failure such as SC-only syndrome (SCOS). However, whether this complicated pathogenesis is regulated by certain miRNAs at the post-transcriptional level remain fascinating but largely unknown. Here we show for the first time that mmu-miR-320-3p was exclusively expressed in murine SCs and this expression was significantly induced in busulphan-treated murine testis. The most efficient stimulatory germ cell types for the induction of apoptosis-elicited mmu-miR-320-3p expression were meiotic spermatocytes and haploid spermatids. Functionally, forced expression of the exogenous mmu-miR-320-3p in SCs compromises male fertility by causing oligozoospermia and defection of sperm mobility. Mechanistically, mmu-miR-320-3p negatively regulates lactate production of SCs by directly inhibiting glucose transporter 3 (GLUT3) expression. Thus, dysregulation of mmu-miR-320-3p/GLUT3 cascade and consequently of lactate deficiency may be a key molecular event contributing the germ cell loss by SC dysfunction. Future endeavor in the continuous investigation of this important circulating miRNA may shed novel insights into epigenetic regulation of SCs nursery function and the etiology of azoospermia, and offers novel therapeutic and prognostic targets for SCOS.

Viral MicroRNAs, Host MicroRNAs Regulating Viruses, and Bacterial MicroRNA-Like RNAs

As masters of genome-wide regulation, miRNAs represent a key component in the complex architecture of cellular processes. Over the last decade, it has become increasingly apparent that miRNAs have many important roles in the development of disease and cancer. Recently, however, their role in viral and bacterial gene regulation as well as host gene regulation during disease progression has become a field of interest. Due to their small size, miRNAs are the ideal mechanism for bacteria and viruses that have limited room in their genomes, as a single miRNA can target up to ~30 genes. Currently, only a limited number of miRNA and miRNA-like RNAs have been found in bacteria and viruses, a number that is sure to increase rapidly in the future. The interactions of these small noncoding RNAs in such primitive species have wide-reaching effects, from increasing viral and bacterial proliferation, better responses to stress, increased virulence, to manipulation of host immune responses to provide a more ideal environment for these pathogens to thrive. Here, we explore those roles to obtain a better grasp of just how complicated disease truly is.

Down-regulation of miRNA-320c promotes tumor growth and metastasis and predicts poor prognosis in human glioma

Emerging studies show that dysregulated miRNAs are implicated in tumorigenesis and progression of various cancers. MiRNA-320c, an important member of miRNA-320 family, was characterized as a new candidate miRNA that suppressed the development of colorectal cancer and bladder cancer. However, the function of miRNA-320c in human glioma remained unclear. Here, we found that miRNA-320c was significantly down-regulated in glioma tissues in contrast with normal brain tissues, being tightly related to clinical stage of glioma by qRT-PCR. Moreover, Kaplan-Meier analysis demonstrated that patients with low miRNA-320c expression had a shorter survival. Multivariate Cox regression analysis indicated that miRNA-320c could serve as an independent poor prognostic factor for patients with glioma. Functionally, overexpression of miRNA-320c could dramatically inhibit glioma cell proliferation, migration and invasion, as well as promote apoptosis. Further analysis indicated that overexpression of miRNA-320c dramatically led to the G0/G1 phase arrest and correspondingly decreased the percentage of S phase cells by suppressing the expression of G1/S transition key regulators, such as Cyclin D1 and CDK6. Additionally, up-regulation of miRNA-320c could significantly impair migration and invasion of glioma cells via reducing the expression of MMP2, MMP9, N-cadherin and Integrin β1. Collectively, our data revealed that miRNA-320c played a crucial role in the carcinoma processes of glioma and might serve as a new prognosis biomarker and therapeutic target of glioma.

Regulation of insulin resistance and type II diabetes by hepatitis C virus infection: A driver function of circulating miRNAs

Hepatitis C virus (HCV) infection is a serious worldwide healthcare issue. Its association with various liver diseases including hepatocellular carcinoma (HCC) is well studied. However, the study on the relationship between HCV infection and the development of insulin resistance and diabetes is very limited. Current research has already elucidated some underlying mechanisms, especially on the regulation of metabolism and insulin signalling by viral proteins. More studies have emerged recently on the correlation between HCV infection‐derived miRNAs and diabetes and insulin resistance. However, no studies have been carried out to directly address if these miRNAs, especially circulating miRNAs, have causal effects on the development of insulin resistance and diabetes. Here, we proposed a new perspective that circulating miRNAs can perform regulatory functions to modulate gene expression in peripheral tissues leading to insulin resistance and diabetes, rather than just a passive factor associated with these pathological processes. The detailed rationales were elaborated through comprehensive literature review and bioinformatic analyses. miR‐122 was identified to be one of the most potential circulating miRNAs to cause insulin resistance. This result along with the idea about the driver function of circulating miRNAs will promote further investigations that eventually lead to the development of novel strategies to treat HCV infection‐associated extrahepatic comorbidities.

Serum microRNA profiles in patients with chronic hepatitis B, chronic hepatitis C, primary biliary cirrhosis, autoimmune hepatitis, nonalcoholic steatohepatitis, or drug-induced liver injury

PURPOSE

Some blood biomarkers or histological examination by liver biopsy are used for the diagnosis of liver diseases in clinics. However, conventional blood biomarkers show poor specificity and sensitivity, and liver biopsy is highly invasiveness. Therefore, to overcome such disadvantages, specific/sensitive and noninvasive options are desirable. In recent years, circulating microRNAs (miRNAs) have been acknowledged for their potential as disease markers. Actually, several miRNAs have been reported to be biomarker candidates of liver diseases. However, these earlier studies were performed for one disease. Therefore, the specificity as biomarkers was not guaranteed, because they didn't study for the other types of liver injury. In this study, we examined if circulating miRNA could distinguish different types of liver diseases.

METHODS

Serum miRNA profiles in 28 patients with chronic hepatitis B, chronic hepatitis C, primary biliary cirrhosis, autoimmune hepatitis, nonalcoholic steatohepatitis or drug-induced liver injury as well as 4 control subjects were determined by TaqMan MicroRNA Array analysis. Principal component analysis (PCA) of selected miRNAs was performed.

RESULTS

We identified 37 miRNAs whose levels were significantly different between any of the groups. Although individual miRNAs could not distinguish different types of liver diseases, probably because of similar liver pathology, their profiling by PCA could classify different liver disease groups.

CONCLUSIONS

The profiling of the selected miRNAs can be useful to distinguish different types of liver diseases.

Circulating MicroRNAs As Potential Biomarkers for Veterinary Infectious Diseases

MicroRNAs (miRNAs) are a kind of small non-coding RNA molecules that could regulate multiple biological pathways at posttranscriptional level. Over 2,000 miRNAs have so far been discovered in humans, and many of them are found to be linked to various kinds of diseases. Thus, miRNAs are being considered as clinical diagnostic and therapeutic targets. With the discovery of high stability of circulating miRNAs in various kinds of mammalian body fluids, the potential of circulating miRNAs as diagnostic/prognostic biomarkers of infectious diseases aroused great interest among researchers. As far as human diseases are concerned, some biomarkers based on circulating miRNAs have been progressed to clinical application. In veterinary fields, however, this concept is only beginning to come into view. In this review, we summarize an update of preclinical studies on using circulating miRNAs as diagnostic biomarkers to combat infectious diseases that affect domestic animals.

Changes in microRNA expression in response to Schistosoma japonicum infection

Schistosomiasis japonicum is one of the most serious zoonotic diseases in the world. There is increasing evidence to show that host miRNAs are modulated following Schistosoma japonicum infection, and some of these miRNAs may play important regulatory roles in response to schistosome infection. Several host miRNAs have been identified and shown to be potential diagnostic biomarkers or novel therapeutic targets for schistosomiasis. These studies have paved the way to a better understanding of the mechanisms of schistosome-host interaction and may facilitate the development of novel approaches to the control of the disease.

miR-134: A Human Cancer Suppressor?

MicroRNAs (miRNAs) are small noncoding RNAs approximately 20-25 nt in length, which play crucial roles through directly binding to corresponding 3' UTR of targeted mRNAs. It has been reported that miRNAs are involved in numerous of diseases, including cancers. Recently, miR-134 has been identified to dysregulate in handles of human cancers, such as lung cancer, glioma, breast cancer, colorectal cancer, and so on. Increasing evidence indicates that miR-134 is essential for human carcinoma and participates in tumor cell proliferation, apoptosis, invasion and metastasis, drug resistance, as well as cancer diagnosis, treatment, and prognosis. Nevertheless, its roles in human cancer are still ambiguous, and its mechanisms are sophisticated as well, referring to a variety of targets and signal pathways, such as STAT5B, KRAS, MAPK/ERK signal pathway, Notch pathway, etc. Herein, we review the crucial roles of miR-134 in scores of human cancers via analyzing latest investigations, which might provide evidence for cancer diagnose, treatment, prognosis, or further investigations.

Circulating microRNAs as Potential Biomarkers of Infectious Disease

microRNAs (miRNAs) are a class of small non-coding endogenous RNA molecules that regulate a wide range of biological processes by post-transcriptionally regulating gene expression. Thousands of these molecules have been discovered to date, and multiple miRNAs have been shown to coordinately fine-tune cellular processes key to organismal development, homeostasis, neurobiology, immunobiology, and control of infection. The fundamental regulatory role of miRNAs in a variety of biological processes suggests that differential expression of these transcripts may be exploited as a novel source of molecular biomarkers for many different disease pathologies or abnormalities. This has been emphasized by the recent discovery of remarkably stable miRNAs in mammalian biofluids, which may originate from intracellular processes elsewhere in the body. The potential of circulating miRNAs as biomarkers of disease has mainly been demonstrated for various types of cancer. More recently, however, attention has focused on the use of circulating miRNAs as diagnostic/prognostic biomarkers of infectious disease; for example, human tuberculosis caused by infection with Mycobacterium tuberculosis, sepsis caused by multiple infectious agents, and viral hepatitis. Here, we review these developments and discuss prospects and challenges for translating circulating miRNA into novel diagnostics for infectious disease.

Diagnostic and Prognostic Value of MicroRNA in Viral Diseases

Virology is probably the most rapidly developing field within clinical laboratory medicine. Adequate diagnostic methods exist for the diagnostics of most acute viral infections. However, emergence of pathogenic viruses or virus strains and new disease associations of known viruses require the establishment of new diagnostic methods, sometimes very rapidly. In the field of chronic or persistent viral diseases, particularly those involving potential of malignant or fatal development, there is a constant need for improved differential diagnostics, monitoring, prognosis and risk assessment. Increasing understanding of disease pathogenesis also enables better patient management and personalized medicine, where companion diagnostics can offer precise and specific tools for individual care. Very often the new tools are offered by molecular diagnostic techniques, and this includes the detection of microRNAs (miRNAs). miRNAs are small regulatory RNA molecules, which regulate the expression of their target genes. They are encoded both by viruses and their host, and both can target either viral or cellular gene expression. In this review the diagnostic possibilities offered by miRNA will be discussed. The focus will be on selected viral and human miRNAs in viral diseases, and examples of miRNAs of putative diagnostic potential will be presented.

MicroRNAs Modulate Pathogenesis Resulting from Chlamydial Infection in Mice

Not all women infected with chlamydiae develop upper genital tract disease, but the reason(s) for this remains undefined. Host genetics and hormonal changes associated with the menstrual cycle are possible explanations for variable infection outcomes. It is also possible that disease severity depends on the virulence of the chlamydial inoculum. It is likely that the inoculum contains multiple genetic variants, differing in virulence. If the virulent variants dominate, then the individual is more likely to develop severe disease. Based on our previous studies, we hypothesized that the relative degree of virulence of a chlamydial population dictates the microRNA (miRNA) expression profile of the host, which, in turn, through regulation of the host inflammatory response, determines disease severity. Thus, we infected C57BL/6 mice with two populations of Chlamydia muridarum, each comprised of multiple genetic variants and differing in virulence: an attenuated strain (Nigg_A) and a virulent strain (Nigg_V). Nigg_A and Nigg_V elicited upper tract pathology in 54% and 91% of mice, respectively. miRNA expression analysis in Nigg_V-infected mice showed significant downregulation of miRNAs involved in dampening fibrosis (miR-200b, miR-200b-5p, and 200b-3p miR-200a-3p) and in transcriptional regulation of cytokine responses (miR-148a-3p, miR-152-3p, miR-132, and miR-212) and upregulation of profibrotic miRNAs (miR-142, and miR-147). Downregulated miRNAs were associated with increased expression of interleukin 8 (IL-8), CXCL2, IL-1β, tumor necrosis factor alpha (TNF-α), and IL-6. Infection with Nigg_V but not Nigg_A led to decreased expression of Dicer and Ago 2, suggesting that Nigg_V interaction with host cells inhibits expression of the miRNA biogenesis machinery, leading to increased cytokine expression and pathology.

Mammalian microRNA: an important modulator of host-pathogen interactions in human viral infections

MicroRNAs (miRNAs), which are small non-coding RNAs expressed by almost all metazoans, have key roles in the regulation of cell differentiation, organism development and gene expression. Thousands of miRNAs regulating approximately 60 % of the total human genome have been identified. They regulate genetic expression either by direct cleavage or by translational repression of the target mRNAs recognized through partial complementary base pairing. The active and functional unit of miRNA is its complex with Argonaute proteins known as the microRNA-induced silencing complex (miRISC). De-regulated miRNA expression in the human cell may contribute to a diverse group of disorders including cancer, cardiovascular dysfunctions, liver damage, immunological dysfunction, metabolic syndromes and pathogenic infections. Current day studies have revealed that miRNAs are indeed a pivotal component of host-pathogen interactions and host immune responses toward microorganisms. miRNA is emerging as a tool for genetic study, therapeutic development and diagnosis for human pathogenic infections caused by viruses, bacteria, parasites and fungi. Many pathogens can exploit the host miRNA system for their own benefit such as surviving inside the host cell, replication, pathogenesis and bypassing some host immune barriers, while some express pathogen-encoded miRNA inside the host contributing to their replication, survival and/or latency. In this review, we discuss the role and significance of miRNA in relation to some pathogenic viruses.

Systematic Identification and Bioinformatic Analysis of MicroRNAs in Response to Infections of Coxsackievirus A16 and Enterovirus 71

Hand, foot, and mouth disease (HFMD), mainly caused by coxsackievirus A16 (CVA16) and enterovirus 71 (EV71) infections, remains a serious public health issue with thousands of newly diagnostic cases each year since 2008 in China. The mechanisms underlying viral infection, however, are elusive to date. In the present study, we systematically investigated the host cellular microRNA (miRNA) expression patterns in response to CVA16 and EV71 infections. Through microarray examination, 27 miRNAs (15 upregulated and 12 downregulated) were found to be coassociated with the replication process of two viruses, while the expression levels of 15 and 5 miRNAs were significantly changed in CVA16- and EV71-infected cells, respectively. A great number of target genes of 27 common differentially expressed miRNAs were predicted by combined use of two computational target prediction algorithms, TargetScan and MiRanda. Comprehensive bioinformatic analysis of target genes in GO categories and KEGG pathways indicated the involvement of diverse biological functions and signaling pathways during viral infection. These results provide an overview of the roles of miRNAs in virus-host interaction, which will contribute to further understanding of HFMD pathological mechanisms.

Circulating let-7 levels in plasma and extracellular vesicles correlate with hepatic fibrosis progression in chronic hepatitis C

The goal of this study was to determine whether an association exists between circulating microRNA (miRNA) levels and disease progression in chronic hepatitis C (CHC), whether plasma or extracellular vesicles (EVs) were optimal for miRNA measurement and their correlation with hepatic miRNA expression, and the mechanistic plausibility of this association. We studied 130 CHC patients prospectively followed over several decades. A comprehensive miRNA profile in plasma using microarray with 2578 probe sets showed 323 miRNAs differentially expressed between healthy individuals and CHC patients, but only six that distinguished patients with mild versus severe chronic hepatitis. Eventually, let-7a/7c/7d-5p and miR-122-5p were identified as candidate predictors of disease progression. Cross-sectional analyses at the time of initial liver biopsy showed that reduced levels of let-7a/7c/7d-5p (let-7s) in plasma were correlated with advanced histological hepatic fibrosis stage and other fibrotic markers, whereas miR-122-5p levels in plasma were positively correlated with inflammatory activity, but not fibrosis. Measuring let-7s levels in EVs was not superior to intact plasma for discriminating significant hepatic fibrosis. Longitudinal analyses in 60 patients with paired liver biopsies showed that let-7s levels in plasma markedly declined over time in parallel with fibrosis progression. However, circulating let-7s levels did not parallel those in the liver.

CONCLUSION

Of all miRNAs screened, the let-7 family showed the best correlation with hepatic fibrosis in CHC. A single determination of let-7s levels in plasma did not have superior predictive value for significant hepatic fibrosis compared with that of fibrosis-4 index, but the rate of let-7s decline in paired longitudinal samples correlated well with fibrosis progression. Pathway analysis suggested that low levels of let-7 may influence hepatic fibrogenesis through activation of transforming growth factor β signaling in hepatic stellate cells. (Hepatology 2016;64:732-745).

Nucleolin-aptamer therapy in retinoblastoma: molecular changes and mass spectrometry-based imaging

Retinoblastoma (RB) is an intraocular childhood tumor which, if left untreated, leads to blindness and mortality. Nucleolin (NCL) protein which is differentially expressed on the tumor cell surface, binds ligands and regulates carcinogenesis and angiogenesis. We found that NCL is over expressed in RB tumor tissues and cell lines compared to normal retina. We studied the effect of nucleolin-aptamer (NCL-APT) to reduce proliferation in RB tumor cells. Aptamer treatment on the RB cell lines (Y79 and WERI-Rb1) led to significant inhibition of cell proliferation. Locked nucleic acid (LNA) modified NCL-APT administered subcutaneously (s.c.) near tumor or intraperitoneally (i.p.) in Y79 xenografted nude mice resulted in 26 and 65% of tumor growth inhibition, respectively. Downregulation of inhibitor of apoptosis proteins, tumor miRNA-18a, altered serum cytokines, and serum miRNA-18a levels were observed upon NCL-APT treatment. Desorption electrospray ionization mass spectrometry (DESI MS)-based imaging of cell lines and tumor tissues revealed changes in phosphatidylcholines levels upon treatment. Thus, our study provides proof of concept illustrating NCL-APT-based targeted therapeutic strategy and use of DESI MS-based lipid imaging in monitoring therapeutic responses in RB.

MicroRNA expression profiling of Leishmania donovani-infected host cells uncovers the regulatory role of MIR30A-3p in host autophagy

Leishmania is an obligate intracellular parasite that replicates inside phagolysosomes or parasitophorous vacuoles (PV) of the monocyte/macrophage lineage. It reprograms macrophages and produces a metabolic state conducive to successful infection and multiplication. MicroRNAs (miRNAs), a class of small 22 to 24 nucleotide noncoding regulatory RNAs alter the gene expression and consequently proteome output by targeting mRNAs, may play a regulatory role in modulating host cell functions. In the present study, we demonstrate the novel regulatory role of host microRNA, MIR30A-3p in modulation of host cell macroautophagy/autophagy after infection with L. donovani. Our in vitro studies showed that MIR30A-3p expression was significantly enhanced after L. donovani infection in a time-dependent manner. Transient transfection with a MIR30A-3p inhibitor followed by L. donovani infection promoted the autophagic response and decreased the intracellular parasite burden in both THP-1 cells and human monocyte-derived macrophages (HsMDM). BECN1/Beclin 1, the mammalian ortholog of yeast Vps30/Atg6, is a key autophagy-promoting protein that plays a key role in the regulation of cell death and survival. We report BECN1-dependent modulation of host cell autophagy in response to L. donovani infection. Pretreatment of L. donovani-infected macrophages with the MIR30A-3p mimic decreased and with antagomir increased the expression of BECN1 protein. We demonstrate that BECN1 is a potential target of MIR30A-3p and this miRNA negatively regulates BECN1 expression. Our present study reveals for the first time a novel role of MIR30A-3p in regulating autophagy-mediated L. donovani elimination by targeting BECN1. The present study has significant impact for the treatment of visceral leishmaniasis.

The Role of MicroRNAs in Response to Interferon Treatment of Chronic Hepatitis C patients

Introduction

Treatment of HCV using a combination of pegylated interferon (PEG-IFN) and ribavirin fails in about 40% of the patients with HCV genotype 4 infections, and it is physically and economically demanding. Thus, it is highly important to identify factors that can help to predict the likelihood that a patient will respond to this treatment.

Methods

In this study, five miRNAs, i.e., miRNA-122, miRNA-199, miRNA-192, miRNA-30, and miRNA-128, were selected according to previous studies that demonstrated their noticeable functions in viral replication, indicating that they potentially could be used by host cells to control viral infections. The five miRNAs were measured using real-time, reverse transcription-polymerase chain reactions. The data were analyzed using the t-test and chi-squared test.

Results

We found that the expression level of miRNA-122 was significantly increased in the responders’ group (p < 0.01) over that in the non-responders’ groups before and after treatment; both increased significantly (p < 0.01) compared with the normal control group.

Conclusion

miR-122 might be a useful predictor for virological responses to treatment with PEG-interferon plus ribavirin therapy in patients with HCV.