Preliminary microRNA analysis in lung tissue to identify potential therapeutic targets against H5N1 infection

miR-29a is a negative regulator of influenza virus infection through targeting of the frizzled 5 receptor

Influenza A virus (IAV) infections result in a large number of deaths and substantial economic losses each year. MicroRNAs repress gene expression and are involved in virus-host interactions. miR-29a is known to have anti-tumor and anti-fibrotic effects. However, the role of miR-29a in IAV infection is unclear. In the present study, we investigated the effect of miR-29a on IAV infection and the mechanisms by which it functions. IAV infection was found to cause decreased miR-29a expression in lung epithelial A549 cells and mouse lungs. Overexpression of miR-29a reduced IAV mRNA and protein levels and progeny virus production in HEK293 and A549 cells. Inhibition of IAV infection by miR-29a was observed with different strains of IAV, including A/PR/8/34, A/WSN/1933, and clinical isolates A/OK/3052/09 and A/OK/309/06 H3N2. Knockout of miR-29a using CRISPR/Cas9 resulted in an increase in viral mRNA and protein levels, confirming that miR-29a suppresses IAV infection. A 3' untranslated region (3'-UTR) reporter assay showed that miR-29a had binding sites in the 3'-UTR of the Wnt-Ca²⁺ signaling receptor frizzled 5 gene, and overexpression of miR-29a reduced the level of the endogenous frizzled 5 protein. Wnt5a treatment of HEK293 and A549 cells enhanced IAV infection. Our results suggest that miR-29a inhibits IAV infection, probably via the frizzled 5 receptor.

Integrated Analysis of microRNA-mRNA Expression in Mouse Lungs Infected With H7N9 Influenza Virus: A Direct Comparison of Host-Adapting PB2 Mutants

MicroRNAs (miRNAs) are important regulators involved in the antiviral response to influenza virus infection, however, an analytical comparison of miRNA and mRNA expression changes induced by several H7N9 host-adapting PB2 mutants remains undone. Here, miRNA microarray and transcriptome sequencing of BALB/c mouse lungs infected with A/Anhui/1/2013 (H7N9) [hereafter referred to as H7N9/AH1-PB2-627K(WT)] and mutant variants with PB2 amino acid substitutions (avian-like H7N9/AH1-PB2-627E and mammalian-adapted H7N9/AH1-PB2-627E/701N) were directly compared. The results showed that influenza virus infection induced dysregulation of numerous host cell processes. In a miRNA-mRNA network associated with immunity, changes in the expression of 38 miRNAs and 58 mRNAs were detected following influenza virus infection. Notably, the miRNAs of mmu-miR-188-5p, mmu-miR-511-5p, mmu-miR-483-5p, and mmu-miR-690 were specifically associated with the replication of the avian-like virus H7N9/AH1-PB2-627E. Likewise, the miRNAs of mmu-miR-691, mmu-miR-329-3p, and mmu-miR-144-3p were specifically associated with the mammalian-adapted virus H7N9/AH1-PB2-627E/701N. Finally, the miRNAs of mmu-miR-98-5p, mmu-miR-103-3p, mmu-miR-199a-5p, and mmu-miR-378a-3p were specifically associated with H7N9/AH1-PB2-627K(WT) virus replication. This is the first report of comparative integration analysis of miRNA-mRNA expression of these three H7N9 influenza viruses with different host-adapting PB2 mutations. Our results highlight potential miRNAs of importance in influenza virus pathogenesis.

Comparative analysis of MicroRNA expression in dog lungs infected with the H3N2 and H5N1 canine influenza viruses

MicroRNAs, a class of noncoding RNAs 18 to 23 nucleotides (nt) in length, play critical roles in a wide variety of biological processes. The objective of this study was to examine differences in microRNA expression profiles derived from the lungs of beagle dogs infected with the avian-origin H3N2 canine influenza virus (CIV) or the highly pathogenic avian influenza (HPAI) H5N1 virus (canine-origin isolation strain). After dogs were infected with H3N2 or H5N1, microRNA expression in the lungs was assessed using a deep-sequencing approach. To identify the roles of microRNAs in viral pathogenicity and the host immune response, microRNA target genes were predicted, and their functions were analyzed using bioinformatics software. A total of 229 microRNAs were upregulated in the H5N1 infection group compared with those in the H3N2 infection group, and 166 microRNAs were downregulated. MicroRNA target genes in the H5N1 group were more significantly involved in metabolic pathways, such as glycerolipid metabolism and glycerophospholipid metabolism, than those in the H3N2 group. The inhibition of metabolic pathways may lead to appetite loss, weight loss and weakened immunity. Moreover, miR-485, miR-144, miR-133b, miR-4859-5p, miR-6902-3p, miR-7638, miR-1307-3p and miR-1346 were significantly altered microRNAs that potentially led to the inhibition of innate immune pathways and the heightened pathogenicity of H5N1 compared with that of H3N2 in dogs. This study deepens our understanding of the complex relationships among microRNAs, the influenza virus-mediated immune response and immune injury in dogs.

cfa-miR-143 Promotes Apoptosis via the p53 Pathway in Canine Influenza Virus H3N2-Infected Cells

MicroRNAs regulate multiple aspects of the host response to viral infection. This study verified that the expression of cfa-miR-143 was upregulated in vivo and in vitro by canine influenza virus (CIV) H3N2 infection. To understand the role of cfa-miR-143 in CIV-infected cells, the target gene of cfa-miR-143 was identified and assessed for correlations with proteins involved in the apoptosis pathway. A dual luciferase reporter assay showed that cfa-miR-143 targets insulin-like growth factor binding protein 5 (Igfbp5). Furthermore, a miRNA agomir and antagomir of cfa-miR-143 caused the downregulation and upregulation of Igfbp5, respectively, in CIV-infected madin-darby canine kidney (MDCK) cells. This study demonstrated that cfa-miR-143 stimulated p53 and caspase3 activation and induced apoptosis via the p53 pathway in CIV H3N2-infected cells. In conclusion, CIV H3N2 induced the upregulation of cfa-miR-143, which contributes to apoptosis via indirectly activating the p53-caspase3 pathway.

The highly pathogenic H5N1 influenza A virus down-regulated several cellular MicroRNAs which target viral genome

Higher and prolonged viral replication is critical for the increased pathogenesis of the highly pathogenic avian influenza (HPAI) subtype of H5N1 influenza A virus (IAV) over the lowly pathogenic H1N1 IAV strain. Recent studies highlighted the considerable roles of cellular miRNAs in host defence against viral infection. In this report, using a 3'UTR reporter system, we identified several putative miRNA target sites buried in the H5N1 virus genome. We found two miRNAs, miR-584-5p and miR-1249, that matched with the PB2 binding sequence. Moreover, we showed that these miRNAs dramatically down-regulated PB2 expression, and inhibited replication of H5N1 and H1N1 IAVs in A549 cells. Intriguingly, these miRNAs expression was differently regulated in A549 cells infected with the H5N1 and H1N1 viruses. Furthermore, transfection of miR-1249 inhibitor enhanced the PB2 expression and promoted the replication of H5N1 and H1N1 IAVs. These results suggest that H5N1 virus may have evolved a mechanism to escape host-mediated inhibition of viral replication through down-regulation of cellular miRNAs, which target its viral genome.

MicroRNAs in the Host Response to Viral Infections of Veterinary Importance

The discovery of small regulatory non-coding RNAs has been an exciting advance in the field of genomics. MicroRNAs (miRNAs) are endogenous RNA molecules, approximately 22 nucleotides in length, that regulate gene expression, mostly at the posttranscriptional level. MiRNA profiling technologies have made it possible to identify and quantify novel miRNAs and to study their regulation and potential roles in disease pathogenesis. Although miRNAs have been extensively investigated in viral infections of humans, their implications in viral diseases affecting animals of veterinary importance are much less understood. The number of annotated miRNAs in different animal species is growing continuously, and novel roles in regulating host–pathogen interactions are being discovered, for instance, miRNA-mediated augmentation of viral transcription and replication. In this review, we present an overview of synthesis and function of miRNAs and an update on the current state of research on host-encoded miRNAs in the genesis of viral infectious diseases in their natural animal host as well as in selected in vivo and in vitro laboratory models.

Small Non-coding RNAs Associated with Viral Infectious Diseases of Veterinary Importance: Potential Clinical Applications

MicroRNAs (miRNAs) represent a class of small non-coding RNA (sncRNA) molecules that can regulate mRNAs by inducing their degradation or by blocking translation. Considering that miRNAs are ubiquitous, stable, and conserved across animal species, it seems feasible to exploit them for clinical applications. Unlike in human viral diseases, where some miRNA-based molecules have progressed to clinical application, in veterinary medicine, this concept is just starting to come into view. Clinically, miRNAs could represent powerful diagnostic tools to pinpoint animal viral diseases and/or prognostic tools to follow up disease progression or remission. Additionally, the possible consequences of miRNA dysregulation make them potential therapeutic targets and open the possibilities to use them as tools to generate viral disease-resistant livestock. This review presents an update of preclinical studies on using sncRNAs to combat viral diseases that affect pet and farm animals. Moreover, we discuss the possibilities and challenges of bringing these bench-based discoveries to the veterinary clinic.

The Effect of Oseltamivir on the Disease Progression of Lethal Influenza A Virus Infection: Plasma Cytokine and miRNA Responses in a Mouse Model

Lethal influenza A virus infection leads to acute lung injury and possibly lethal complications. There has been a continuous effort to identify the possible predictors of disease severity. Unlike earlier studies, where biomarkers were analyzed on certain time points or days after infection, in this study biomarkers were evaluated over the entire course of infection. Circulating proinflammatory cytokines and/or miRNAs that track with the onset and progression of lethal A/Puerto Rico/8/34 (PR8) influenza A virus infection and their response to oseltamivir treatment were investigated up to 10 days after infection. Changes in plasma cytokines (IL-1β, IL-10, IL-12p70, IL-6, KC, TNF-α, and IFN-γ) and several candidate miRNAs were profiled. Among the cytokines analyzed, IL-6 and KC/GRO cytokines appeared to correlate with peak viral titer. Over the selected 48 miRNAs profiled, certain miRNAs were up- or downregulated in a manner that was dependent on the oseltamivir treatment and disease severity. Our findings suggest that IL-6 and KC/GRO cytokines can be a potential disease severity biomarker and/or marker for the progression/remission of infection. Further studies to explore other cytokines, miRNAs, and lung injury proteins in serum with different subtypes of influenza A viruses with varying disease severity may provide new insight into other unique biomarkers.

Human microRNAs profiling in response to influenza A viruses (subtypes pH1N1, H3N2, and H5N1)

MicroRNAs (miRNAs) play an important role in regulation of gene silencing and are involved in many cellular processes including inhibition of infected viral replication. This study investigated cellular miRNA expression profiles operating in response to influenza virus in early stage of infection which might be useful for understanding and control of viral infection. A549 cells were infected with different subtypes of influenza virus (pH1N1, H3N2 and H5N1). After 24 h post-infection, miRNAs were extracted and then used for DNA library construction. All DNA libraries with different indexes were pooled together with equal concentration, followed by high-throughput sequencing based on MiSeq platform. The miRNAs were identified and counted from sequencing data by using MiSeq reporter software. The miRNAs expressions were classified into up and downregulated miRNAs compared to those found in non-infected cells. Mostly, each subtype of influenza A virus triggered the upregulated responses in miRNA expression profiles. Hsa-miR-101, hsa-miR-193b, hsa-miR-23b, and hsa-miR-30e* were upregulated when infected with all three subtypes of influenza A virus. Target prediction results showed that virus infection can trigger genes in cellular process, metabolic process, developmental process and biological regulation. This study provided some insights into the cellular miRNA profiling in response to various subtypes of influenza A viruses in circulation and which have caused outbreaks in human population. The regulated miRNAs might be involved in virus-host interaction or host defense mechanism, which should be investigated for effective antiviral therapeutic interventions.

Identification of microRNAs in Throat Swab as the Biomarkers for Diagnosis of Influenza

BACKGROUND

Influenza is a serious worldwide disease that captures global attention in the past few years after outbreaks. The recent discoveries of microRNA (miRNA) and its unique expression profile in influenza patients have offered a new method for early influenza diagnosis. The aim of this study was to examine the utility of miRNAs for the diagnosis of influenza.

METHODS

Thirteen selected miRNAs were investigated with the hosts' throat swabs (25 H1N1, 20 H3N2, 20 influenza B and 21 healthy controls) by real-time quantitative polymerase chain reaction (RT-qPCR) using U6 snRNA as endogenous control for normalization, and receiver operating characteristic (ROC) curve/Area under curve (AUC) for analysis.

RESULTS

miR-29a-3p, miR-30c-5p, miR-34c-3p and miR-181a-5p are useful biomarkers for influenza A detection; and miR-30c-5p, miR-34b-5p, miR-205-5p and miR-449b-5p for influenza B detection. Also, use of both miR-30c-5p and miR-34c-3p (AUC=0.879); and miR-30c-5p and miR-449b-5p (AUC=0.901) are better than using one miRNA to confirm influenza A and influenza B infection, respectively.

CONCLUSIONS

Given its simplicity, non-invasiveness and specificity, we found that the throat swab-derived miRNAs miR-29a-3p, miR-30c-5p, miR-34b-5p, miR-34c-3p, miR-181a-5p, miR-205-5p and miR-449b-5p are a useful tool for influenza diagnosis on influenza A and B.

MicroRNA expression profiles and networks in mouse lung infected with H1N1 influenza virus

Influenza A viruses can cause localized outbreaks and worldwide pandemics, owing to their high transmissibility and wide host range. As such, they are among the major diseases that cause human death. However, the molecular changes induced by influenza A virus infection in lung tissue are not entirely clear. Changes in microRNA (miRNA) expression occur in many pathological and physiological processes, and influenza A virus infection has been shown to alter miRNA expression in cultured cells and animal models. In this study, we mined key miRNAs closely related to influenza A virus infection and explored cellular regulatory mechanisms against influenza A virus infection, by building networks among miRNAs and genes, gene ontologies (GOs), and pathways. In this study, miRNAs and mRNAs induced by H1N1 influenza virus infection were measured by gene chips, and we found that 82 miRNAs and 3371 mRNAs were differentially expressed. The 82 miRNAs were further analyzed with the series test of cluster (STC) analysis. Three of the 16 cluster profiles identified by STC, which include 46 miRNAs in the three profiles, changed significantly. Using potential target genes of the 46 miRNAs, we looked for intersections of these genes with 3371 differentially expressed mRNAs; 719 intersection genes were identified. Based on the GO or KEGG databases, we attained GOs or pathways for all of the above intersection genes. Fisher's and χ (2) test were used to calculate p value and false discovery rate (FDR), and according to the standard of p < 0.001, 241 GOs and 76 pathways were filtered. Based on these data, miRNA-gene, miRNA-GO, and miRNA-pathway networks were built. We then extracted three classes of GOs (related to inflammatory and immune response, cell cycle, proliferation and apoptosis, and signal transduction) to build three subgraphs, and pathways strictly related with H1N1 influenza virus infection were filtered to extract a subgraph of the miRNA-pathway network. Last, according to the pathway analysis and miRNA-pathway network analysis, 17 miRNAs were found to be associated with the "influenza A" pathway. This study provides the most complete miRNAome profiles, and the most detailed miRNA regulatory networks to date, and is the first to report the most important 17 miRNAs closely related with the pathway of influenza A. These results are a prelude to advancements in mouse H1N1 influenza virus infection biology and the use of mice as a model for human H1N1 influenza virus infection studies.

Differential microRNA expression following infection with a mouse-adapted, highly virulent avian H5N2 virus

Background

MicroRNAs (miRNAs) are known to regulate various biological processes, including expression of cellular gene and virus-induced inflammation. Recently, studies have indicated that some miRNAs could regulate influenza virus replication. Due to differential sensitivities of influenza A virus strains to different species (avian and mammalian), variations in host responses may be observed. Therefore, we investigated and compared the differences in global host miRNA expression in mouse lungs infected with wild type low pathogenicity A/Aquatic bird/Korea/w81/2005 (H5N2) (w81) or mouse-adapted virulent A/Aquatic bird /Korea/ma81/2007 (H5N2) (ma81) virus.

Results

Although the mice infected with ma81 exhibited much greater mortality than w81-infected mice, the parental w81 virus induced a higher number of differentially expressed miRNAs compared to the ma81 virus. Between these 2 viruses, a total of 27 and 20 miRNAs were commonly expressed at 1 dpi and 3 dpi, respectively. It is noteworthy that only 9 miRNAs (miR-100-5p, miR-130a-5p, miR-146b-3p, miR-147-3p, miR-151-5p, miR-155-3p, miR-223-3p, miR-301a-3p, and miR-495-3p) were significantly upregulated in both lungs infected with either wild type w81 or the mouse-adapted ma81 strain at both time points. Notably, expression levels of miR-147-3p, miR-151-5p, miR-155-3p, and miR-223-3p were higher in the lungs of mice infected with the ma81 virus than those infected with the w81 virus. To identify potential roles of these miRNAs in regulating influenza virus replication, each group of mice was intranasally treated with each inhibitor of specifically targeting 4 miRNAs, and then challenged with 5 mouse lethal dose 50% (MLD₅₀) of the virulent ma81 virus on the following day. Although the specific miRNA inhibitors could not completely attenuate mortality or reduce viral replication, the miR-151-5p- and miR-223-3p-inhibitors reduced mortality of inoculated mice to 70% and substantially delayed death.

Conclusions

Our results suggest that the mammalian adaptation of avian influenza A virus results in a different miRNA expression pattern in lungs of virus-infected mice compared with its parental strain, and use of specific miRNA inhibitors to target genes associated with the immune response or cell death may affect virulence and virus replication.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-014-0252-0) contains supplementary material, which is available to authorized users.

MicroRNA expression in mice infected with seasonal H1N1, swine H1N1 or highly pathogenic H5N1

Influenza virus infections in humans remain a healthcare concern, and the need for vaccines, therapeutics and prophylactics remains a high priority. Understanding the molecular events associated with influenza-virus-induced pathology may lead to the identification of clinical disease biomarkers and novel antiviral targets. MicroRNAs (miRNAs) are well-conserved endogenous non-coding RNAs known to regulate post-transcriptional gene expression as well as play a major role in many biological processes and pathways. Animal studies have demonstrated that miRNAs are involved in viral disease and controlling inflammation. In this study, we examined the differences in the miRNA expression profiles associated with the lung in mice infected with influenza viruses that varied in virulence and pathogenicity. A statistical model was employed that utilized changes in miRNA expression to identify the virus that was used to infect the mice. This study identified a unique fingerprint of viral pathogenicity associated with seasonal H1N1, swine H1N1 and highly pathogenic H5N1 in the mouse model, and may lead to the identification of novel therapeutic and prophylactic targets.

MicroRNA expression profile of mouse lung infected with 2009 pandemic H1N1 influenza virus

MicroRNAs have been implicated in the regulation of gene expression of various biological processes in a post-transcriptional manner under physiological and pathological conditions including host responses to viral infections. The 2009 pandemic H1N1 influenza virus is an emerging reassortant strain of swine, human and bird influenza virus that can cause mild to severe illness and even death. To further understand the molecular pathogenesis of the 2009 pandemic H1N1 influenza virus, we profiled cellular microRNAs of lungs from BALB/c mice infected with wild-type 2009 pandemic influenza virus A/Beijing/501/2009 (H1N1) (hereafter referred to as BJ501) and mouse-adapted influenza virus A/Puerto Rico/8/1934 (H1N1) (hereafter referred to as PR8) for comparison. Microarray analysis showed both the influenza virus BJ501 and PR8 infection induced strain- and temporal-specific microRNA expression patterns and that their infection caused a group of common and distinct differentially expressed microRNAs. Characteristically, more differentially expressed microRNAs were aroused on day 5 post infection than on day 2 and more up-regulated differentially expressed microRNAs were provoked than the down-regulated for both strains of influenza virus. Finally, 47 differentially expressed microRNAs were obtained for the infection of both strains of H1N1 influenza virus with 29 for influenza virus BJ501 and 43 for PR8. Among them, 15 microRNAs had no reported function, while 32 including miR-155 and miR-233 are known to play important roles in cancer, immunity and antiviral activity. Pathway enrichment analyses of the predicted targets revealed that the transforming growth factor-β (TGF-β) signaling pathway was the key cellular pathway associated with the differentially expressed miRNAs during influenza virus PR8 or BJ501 infection. To our knowledge, this is the first report of microRNA expression profiles of the 2009 pandemic H1N1 influenza virus in a mouse model, and our findings might offer novel therapy targets for influenza virus infection.

Microarray analysis of microRNA expression in peripheral blood mononuclear cells of critically ill patients with influenza A (H1N1)

BACKGROUND

With concerns about the disastrous health and economic consequences caused by the influenza pandemic, comprehensively understanding the global host response to influenza virus infection is urgent. The role of microRNA (miRNA) has recently been highlighted in pathogen-host interactions. However, the precise role of miRNAs in the pathogenesis of influenza virus infection in humans, especially in critically ill patients is still unclear.

METHODS

We identified cellular miRNAs involved in the host response to influenza virus infection by performing comprehensive miRNA profiling in peripheral blood mononuclear cells (PBMCs) from critically ill patients with swine-origin influenza pandemic H1N1 (2009) virus infection via miRNA microarray and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) assays. Receiver operator characteristic (ROC) curve analysis was conducted and area under the ROC curve (AUC) was calculated to evaluate the diagnostic accuracy of severe H1N1 influenza virus infection. Furthermore, an integrative network of miRNA-mediated host-influenza virus protein interactions was constructed by integrating the predicted and validated miRNA-gene interaction data with influenza virus and host-protein-protein interaction information using Cytoscape software. Moreover, several hub genes in the network were selected and validated by qRT-PCR.

RESULTS

Forty-one significantly differentially expressed miRNAs were found by miRNA microarray; nine were selected and validated by qRT-PCR. QRT-PCR assay and ROC curve analyses revealed that miR-31, miR-29a and miR-148a all had significant potential diagnostic value for critically ill patients infected with H1N1 influenza virus, which yielded AUC of 0.9510, 0.8951 and 0.8811, respectively. We subsequently constructed an integrative network of miRNA-mediated host-influenza virus protein interactions, wherein we found that miRNAs are involved in regulating important pathways, such as mitogen-activated protein kinase signaling pathway, epidermal growth factor receptor signaling pathway, and Toll-like receptor signaling pathway, during influenza virus infection. Some of differentially expressed miRNAs via in silico analysis targeted mRNAs of several key genes in these pathways. The mRNA expression level of tumor protein T53 and transforming growth factor beta receptor 1 were found significantly reduced in critically ill patients, whereas the expression of Janus kinase 2, caspase 3 apoptosis-related cysteine peptidase, interleukin 10, and myxovirus resistance 1 were extremely increased in critically ill patients.

CONCLUSIONS

Our data suggest that the dysregulation of miRNAs in the PBMCs of H1N1 critically ill patients can regulate a number of key genes in the major signaling pathways associated with influenza virus infection. These differentially expressed miRNAs could be potential therapeutic targets or biomarkers for severe influenza virus infection.