A Computational Approach for Predicting Role of Human MicroRNAs in MERS-CoV Genome

High expression of miR-7974 predicts poor prognosis and is associated with autophagy in estrogen receptor-positive breast cancer

Estrogen receptor-positive (ER+) breast cancers (BC) cause death despite well-established treatments. MicroRNAs (miRNAs) have potential as biomarkers specific to cancer subtypes and tissues, therefore miRNA-based biomarkers could help improve patient survival. In this study, we investigated a relatively unknown miRNA, miR-7974. We utilized small RNA data from 204 breast tissue samples to study miR-7974 association with clinicopathological features and outcomes for BC patients. Additionally, in vitro and in ovo methods were used to identify miR-7974 role at molecular and cellular level in MCF-7 cells. Findings were validated using MDA-MB-453 cells. MiR-7974 was upregulated in many clinicopathological features of BC (P<0.05). Furthermore, the highest expression of miR-7974 was associated with poor relapse-free survival in ER+ BC patients [hazard ratio (HR)=8.70; 95% confidence interval (CI)=3.28-23.06; P=1.37x10-05] and poor BC-specific survival in patients receiving only surgical treatment (HR=8.36; 95% CI=1.01-69.06; P=0.049). Our studies revealed that miR-7974 targets autophagy gene, MAP1LC3B, identified as direct miR-7974 target (P<0.05) in MCF-7 cells. In vitro analyses indicated overexpressing miR-7974 had anti-proliferative effect in MCF7 and MDA-MB-453 cells. Overall, our results demonstrate potential prognostic role of miR-7974 in ER+ BC.

hsa-miR-548d-3p: a potential microRNA to target nucleocapsid and/or capsid genes in multiple members of the Flaviviridae family

Introduction

Flaviviridae comprise a group of enveloped, positive-stranded RNA viruses that are mainly transmitted through either mosquitoes or tick bites and/or contaminated blood, blood products, or other body secretions. These viruses cause diseases ranging from mild to severe and are considered important human pathogens. MicroRNAs (miRNAs) are non-coding molecules involved in growth, development, cell proliferation, protein synthesis, apoptosis, and pathogenesis. These small molecules are even being used as gene suppressors in antiviral therapeutics, inhibiting viral replication. In the current study, we used bioinformatic tools to predict a possible miRNA sequence that could be complementary to the nucleocapsid (NP) and/or capsid (CP) gene of the Flaviviridae family and provide an inhibitory solution.

Methods

Bioinformatics is a field of science that includes tremendous computational analysis, logarithms, and sequence alignments. To predict the right alignments between miRNA and viral mRNA genomes, we used computational databases such as miRBase, NCBI, and Basic Alignment Search Tool-nucleotides (BLAST-n).

Results

Of the 2,600 mature miRNAs, hsa-miR-548d-3p revealed complementary sequences with the flavivirus capsid gene and bovine viral diarrhea virus (BVDV) capsid gene and was selected as a possible candidate to inhibit flaviviruses.

Conclusion

Although more detailed in vitro and in vivo studies are required to test the possible inhibitory effects of hsa-miR-548d-3p against flaviviruses, this computational study may be the first step to study further, developing a novel therapeutic for lethal viruses within the Flaviviridae family using suggested candidate miRNAs.

Computational Prediction of RNA-RNA Interactions between Small RNA Tracks from Betacoronavirus Nonstructural Protein 3 and Neurotrophin Genes during Infection of an Epithelial Lung Cancer Cell Line: Potential Role of Novel Small Regulatory RNA

Whether RNA-RNA interactions of cytoplasmic RNA viruses, such as Betacoronavirus, might end in the biogenesis of putative virus-derived small RNAs as miRNA-like molecules has been controversial. Even more, whether RNA-RNA interactions of wild animal viruses may act as virus-derived small RNAs is unknown. Here, we address these issues in four ways. First, we use conserved RNA structures undergoing negative selection in the genomes of SARS-CoV, MERS-CoV, and SARS-CoV-2 circulating in different bat species, intermediate animals, and human hosts. Second, a systematic literature review was conducted to identify Betacoronavirus-targeting hsa-miRNAs involved in lung cell infection. Third, we employed sophisticated long-range RNA-RNA interactions to refine the seed sequence homology of hsa-miRNAs with conserved RNA structures. Fourth, we used high-throughput RNA sequencing of a Betacoronavirus-infected epithelial lung cancer cell line (Calu-3) to validate the results. We proposed nine potential virus-derived small RNAs: two vsRNAs in SARS-CoV (Bats: SB-vsRNA-ORF1a-3p; SB-vsRNA-S-5p), one vsRNA in MERS-CoV (Bats: MB-vsRNA-ORF1b-3p), and six vsRNAs in SARS-CoV-2 (Bats: S2B-vsRNA-ORF1a-5p; intermediate animals: S2I-vsRNA-ORF1a-5p; and humans: S2H-vsRNA-ORF1a-5p, S2H-vsRNA-ORF1a-3p, S2H-vsRNA-ORF1b-3p, S2H-vsRNA-ORF3a-3p), mainly encoded by nonstructural protein 3. Notably, Betacoronavirus-derived small RNAs targeted 74 differentially expressed genes in infected human cells, of which 55 upregulate the molecular mechanisms underlying acute respiratory distress syndrome (ARDS), and the 19 downregulated genes might be implicated in neurotrophin signaling impairment. These results reveal a novel small RNA-based regulatory mechanism involved in neuropathogenesis that must be further studied to validate its therapeutic use.

Delivery of siRNAs against MERS-CoV in Vero and HEK-293 cells: A comparative evaluation of transfection reagents

Background

A new coronavirus was identified in Jeddah, Saudi Arabia in 2012 and designated as Middle East Respiratory Syndrome Coronavirus (MERS-CoV). To date, this virus has been reported in 27 countries. The virus transmission to humans has already been reported from camels. Currently, there is no vaccine or antiviral therapy available against this virus.

Methods

The siRNAs were in silico predicted, designed, and chemically synthesized by using the MERS-CoV-orf1ab region as a target. The antiviral activity was experimentally evaluated by delivering the siRNAs with Lipofectamine™ 2000 and JetPRIME^R as transfection reagents in both Vero cell and HEK-293-T cell lines at two different concentrations (10.0 nM and 5.0 nM). The Ct value of quantitative Real-Time PCR (qRT-PCR) was used to calculate and determine the reduction of viral RNA level in both cell supernatant and cell lysate isolated from both cell lines.

Results

The sequence alignment resulted in the selection of highly conserved regions. The orf1ab region was used to predict and design the siRNAs and a total of twenty-one siRNAs were finally selected from four hundred and twenty-six siRNAs generated by online software. Inhibition of viral replication and significant reduction of viral RNA was observed against selected siRNAs in both cell lines at both concentrations. Based on the Ct value, the siRNAs # 11, 12, 18, and 20 were observed to be the best performing in both cell lines at both concentrations.

Conclusion

Based on the results and data analysis, it is concluded that the use of two different transfection reagents was significantly effective. But the Lipofectamine™ 2000 was found to be a better transfection reagent than the JetPRIME^R for the delivery of siRNAs in both cell lines.

Computational Design and Experimental Evaluation of MERS-CoV siRNAs in Selected Cell Lines

Middle East respiratory syndrome coronavirus (MERS-CoV) is caused by a well-known coronavirus first identified in a hospitalized patient in the Kingdom of Saudi Arabia. MERS-CoV is a serious pathogen affecting both human and camel health globally, with camels being known carriers of viruses that spread to humans. In this work, MERS-CoV genomic sequences were retrieved and analyzed by multiple sequence alignment to design and predict siRNAs with online software. The siRNAs were designed from the orf1ab region of the virus genome because of its high sequence conservation and vital role in virus replication. The designed siRNAs were used for experimental evaluation in selected cell lines: Vero cells, HEK-293-T, and Huh-7. Virus inhibition was assessed according to the cycle threshold value during a quantitative real-time polymerase chain reaction. Out of 462 potential siRNAs, we filtered out 21 based on specific selection criteria without off-target effect. The selected siRNAs did not show any cellular toxicity in the tested cell lines at various concentrations. Based on our results, it was obvious that the combined use of siRNAs exhibited a reduction in MERS-CoV replication in the Vero, HEK-293-T, and Huh-7 cell lines, with the highest efficacy displayed in the Vero cells.

Changes of Small Non-coding RNAs by Severe Acute Respiratory Syndrome Coronavirus 2 Infection

The ongoing pandemic of coronavirus disease 2019 (COVID-19), which results from the rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a significant global public health threat, with molecular mechanisms underlying its pathogenesis largely unknown. In the context of viral infections, small non-coding RNAs (sncRNAs) are known to play important roles in regulating the host responses, viral replication, and host-virus interaction. Compared with other subfamilies of sncRNAs, including microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), tRNA-derived RNA fragments (tRFs) are relatively new and emerge as a significant regulator of host-virus interactions. Using T4 PNK-RNA-seq, a modified next-generation sequencing (NGS), we found that sncRNA profiles in human nasopharyngeal swabs (NPS) samples are significantly impacted by SARS-CoV-2. Among impacted sncRNAs, tRFs are the most significantly affected and most of them are derived from the 5'-end of tRNAs (tRF5). Such a change was also observed in SARS-CoV-2-infected airway epithelial cells. In addition to host-derived ncRNAs, we also identified several small virus-derived ncRNAs (svRNAs), among which a svRNA derived from CoV2 genomic site 346 to 382 (sv-CoV2-346) has the highest expression. The induction of both tRFs and sv-CoV2-346 has not been reported previously, as the lack of the 3'-OH ends of these sncRNAs prevents them to be detected by routine NGS. In summary, our studies demonstrated the involvement of tRFs in COVID-19 and revealed new CoV2 svRNAs.

Conserved MicroRNAs in Human Nasopharynx Tissue Samples from Swabs Are Differentially Expressed in Response to SARS-CoV-2

The use of high-throughput small RNA sequencing is well established as a technique to unveil the miRNAs in various tissues. The miRNA profiles are different between infected and non-infected tissues. We compare the SARS-CoV-2 positive and SARS-CoV-2 negative RNA samples extracted from human nasopharynx tissue samples to show different miRNA profiles. We explored differentially expressed miRNAs in response to SARS-CoV-2 in the RNA extracted from nasopharynx tissues of 10 SARS-CoV-2-positive and 10 SARS-CoV-2-negative patients. miRNAs were identified by small RNA sequencing, and the expression levels of selected miRNAs were validated by real-time RT-PCR. We identified 943 conserved miRNAs, likely generated through posttranscriptional modifications. The identified miRNAs were expressed in both RNA groups, NegS and PosS: miR-148a, miR-21, miR-34c, miR-34b, and miR-342. The most differentially expressed miRNA was miR-21, which is likely closely linked to the presence of SARS-CoV-2 in nasopharynx tissues. Our results contribute to further understanding the role of miRNAs in SARS-CoV-2 pathogenesis, which may be crucial for understanding disease symptom development in humans.

Plasma miRNA profile at COVID-19 onset predicts severity status and mortality

BACKGROUND

MicroRNAs (miRNAs) have a crucial role in regulating immune response against infectious diseases, showing changes early in disease onset and before the detection of the pathogen. Thus, we aimed to analyze the plasma miRNA profile at COVID-19 onset to identify miRNAs as early prognostic biomarkers of severity and survival.

METHODS AND RESULTS

Plasma miRNome of 96 COVID-19 patients that developed asymptomatic/mild, moderate and severe disease was sequenced together with a group of healthy controls. Plasma immune-related biomarkers were also assessed. COVID-19 patients showed 200 significant differentially expressed (SDE) miRNAs concerning healthy controls, with upregulated putative targets of SARS-CoV-2, and inflammatory miRNAs. Among COVID-19 patients, 75 SDE miRNAs were observed in asymptomatic/mild compared to symptomatic patients, which were involved in platelet aggregation and cytokine pathways, among others. Moreover, 137 SDE miRNAs were identified between severe and moderate patients, where miRNAs targeting the SARS CoV-2 genome were the most strongly disrupted. Finally, we constructed a mortality predictive risk score (miRNA-MRS) with ten miRNAs. Patients with higher values had a higher risk of 90-days mortality (hazard ratio=4.60; p-value<0.001). Besides, the discriminant power of miRNA-MRS was significantly higher than the observed for age and gender (AUROC=0.970 vs. 0.881; p=0.042).

CONCLUSIONS

SARS-CoV-2 infection deeply disturbs the plasma miRNome from an early stage of COVID-19, making miRNAs highly valuable as early predictors of severity and mortality.

The role of microRNAs in COVID-19 with a focus on miR-200c

Objective:

Epigenetics is a quickly spreading scientific field, and the study of epigenetic regulation in various diseases such as infectious diseases is emerging. The microribonucleic acids (miRNAs) as one of the types of epigenetic processes bind to their target messenger RNAs (mRNAs) and regulate their stability and/or translation. This study aims to evaluate non-coding RNAs (ncRNAs) with a focus on miR-200c in COVID-19. In this review, we first define the epigenetics and miRNAs, and then the role of miRNAs in diseases focusing on lung diseases is explained. Finally, in this study, we will investigate the role and position of miRNAs with a focus on miR-200c in viral and severe acute respiratory syndrome–related coronavirus (SARS-CoV2) infections.

Methods:

Systematic search of MEDLINE, PubMed, Web of Science, Embase, and Cochrane Library was conducted for all relative papers from 2000 to 2021 with the limitations of the English language. Finally, we selected 128 articles which fit the best to our objective of study, among which 5 articles focused on the impact of miR-200c.

Results:

Due to the therapeutic results of various drugs in different races and populations, epigenetic processes, especially miRNAs, are important. The overall results showed that different types of miRNAs can be effective on the process of various lung diseases through different target pathways and genes. It is likely that amplified levels of miR-200c may lead to decreased angiotensin-converting enzyme-2 (ACE2) expression, which in turn may increase the potential of infection, inflammation, and the complications of coronavirus disease.

Conclusion:

miR-200c and its correlation with ACE2 can be used as early prognostic and diagnostic markers.

The potential use of microRNAs as a therapeutic strategy for SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, there is no effective therapeutic approach for treating SARS-CoV-2 infections. MicroRNAs (miRNAs) have been recognized to target the viral genome directly or indirectly, thereby inhibiting viral replication. Several studies have demonstrated that host miRNAs target different sites in SARS-CoV-2 RNA and constrain the production of essential viral proteins. Furthermore, miRNAs have lower toxicity, are more immunogenic, and are more diverse than protein-based and even plasmid-DNA-based therapeutic agents. In this review, we emphasize the role of miRNAs in viral infection and their potential use as therapeutic agents against COVID-19 disease. The potential of novel miRNA delivery strategies, especially EDV™ nanocells, for targeting lung tissue for treatment of SARS-CoV-2 infection is also discussed.

In Vitro Inhibitory Analysis of Rationally Designed siRNAs against MERS-CoV Replication in Huh7 Cells

MERS-CoV was identified for the first time in Jeddah, Saudi Arabia in 2012 in a hospitalized patient. This virus subsequently spread to 27 countries with a total of 939 deaths and 2586 confirmed cases and now has become a serious concern globally. Camels are well known for the transmission of the virus to the human population. In this report, we have discussed the prediction, designing, and evaluation of potential siRNA targeting the ORF1ab gene for the inhibition of MERS-CoV replication. The online software, siDirect 2.0 was used to predict and design the siRNAs, their secondary structure and their target accessibility. ORF1ab gene folding was performed by RNAxs and RNAfold software. A total of twenty-one siRNAs were selected from 462 siRNAs according to their scoring and specificity. siRNAs were evaluated in vitro for their cytotoxicity and antiviral efficacy in Huh7 cell line. No significant cytotoxicity was observed for all siRNAs in Huh7 cells. The in vitro study showed the inhibition of viral replication by three siRNAs. The data generated in this study provide preliminary and encouraging information to evaluate the siRNAs separately as well as in combination against MERS-CoV replication in other cell lines. The prediction of siRNAs using online software resulted in the filtration and selection of potential siRNAs with high accuracy and strength. This computational approach resulted in three effective siRNAs that can be taken further to in vivo animal studies and can be used to develop safe and effective antiviral therapies for other prevalent disease-causing viruses.

Computational prediction of potential siRNA and human miRNA sequences to silence orf1ab associated genes for future therapeutics against SARS-CoV-2

The coronavirus disease 2019 (COVID-19) is an ongoing pandemic caused by an RNA virus termed as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). SARS-CoV-2 possesses an almost 30kbp long genome. The genome contains open-reading frame 1ab (ORF1ab) gene, the largest one of SARS-CoV-2, encoding polyprotein PP1ab and PP1a responsible for viral transcription and replication. Several vaccines have already been approved by the respective authorities over the world to develop herd immunity among the population. In consonance with this effort, RNA interference (RNAi) technology holds the possibility to strengthen the fight against this virus. Here, we have implemented a computational approach to predict potential short interfering RNAs including small interfering RNAs (siRNAs) and microRNAs (miRNAs), which are presumed to be intrinsically active against SARS-CoV-2. In doing so, we have screened miRNA library and siRNA library targeting the ORF1ab gene. We predicted the potential miRNA and siRNA candidate molecules utilizing an array of bioinformatic tools. By extending the analysis, out of 24 potential pre-miRNA hairpins and 131 siRNAs, 12 human miRNA and 10 siRNA molecules were sorted as potential therapeutic agents against SARS-CoV-2 based on their GC content, melting temperature (Tm), heat capacity (Cp), hybridization and minimal free energy (MFE) of hybridization. This computational study is focused on lessening the extensive time and labor needed in conventional trial and error based wet lab methods and it has the potential to act as a decent base for future researchers to develop a successful RNAi therapeutic.

The Potential Therapeutic Effect of RNA Interference and Natural Products on COVID-19: A Review of the Coronaviruses Infection

The SARS-CoV-2 virus was reported for the first time in Wuhan, Hubei Province, China, and causes respiratory infection. This pandemic pneumonia killed about 1,437,835 people out of 61,308,161cases up to November 27, 2020. The disease's main clinical complications include fever, recurrent coughing, shortness of breath, acute respiratory syndrome, and failure of vital organs that could lead to death. It has been shown that natural compounds with antioxidant, anticancer, and antiviral activities and RNA interference agents could play an essential role in preventing or treating coronavirus infection by inhibiting the expression of crucial virus genes. This study aims to introduce a summary of coronavirus's genetic and morphological structure and determine the role of miRNAs, siRNAs, chemical drugs, and natural compounds in stimulating the immune system or inhibiting the virus's structural and non-structural genes that are essential for replication and infection of SARS-CoV-2.

In silico prediction and experimental validation of siRNAs targeting ORF1ab of MERS-CoV in Vero cell line

The Middle East Respiratory Syndrome Coronavirus is well known to cause respiratory syndrome and this virus was identified and isolated for the first time from Jeddah, Saudi Arabia in 2012 from infected patient. In this report, we have conducted the in-silico prediction, designing and evaluation of siRNAs targeting Middle East Respiratory Syndrome Coronavirus orf1ab gene to inhibit the virus replication. By using bioinformatics software, total twenty-one functional, off-target reduced siRNA were selected from four hundred and sixty-two siRNAs based on their greater potency and specificity. We have evaluated only seven siRNAs to analyze their performance and efficacy as antivirals by reverse transfection approach in Vero cells. There was no cytotoxicity of siRNAs at various concentrations was observed in Vero cells. Based on the real-time PCR results, better inhibition of viral replication was observed in the siRNA-1 and 4 as compared to other siRNAs. The results generated from this work provided suitable information about the efficacy of siRNAs which encouraged us to further evaluate the remaining siRNAs to determine their inhibitory effect on the virus replication. We concluded that the insilico prediction and designing resulted in the screening of potential siRNAs with better efficiency, and strength. This can be used to develop oligonucleotide-based antiviral therapeutics against MERS-CoV in the near future.

Coronary artery disease: differential expression of ceRNAs and interaction analyses

Background

Previous studies have demonstrated associations between cardiovascular disease and the expression of various messenger RNAs (mRNAs), microRNAs (miRNAs), and long non-coding RNAs (lncRNAs). This study aimed to investigate the differential expression of mRNAs, lncRNAs, and miRNAs between tissues from patients with coronary artery disease (CAD) and healthy controls, and to determine the interactions between these molecules in CAD.

Methods

We investigated the differential expression of competitive endogenous RNAs (ceRNAs) between patients with CAD and healthy controls by collecting data from Gene Expression Omnibus (GEO) microarrays. We also investigated the biological function of these differentially expressed ceRNAs by performing Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. We then created a protein-protein interaction (PPI) network to identify the hub genes. Biosystems and literature searches were also carried out to identify relevant signaling pathways and the potential function of the differentially expressed ceRNAs.

Results

We identified 456 expression profiles for miRNAs, 16,325 mRNA expression profiles, and 2,869 lncRNA expression profiles. With regards to connectivity, GO and KEGG analyses (count ≥9) identified the top 11 PPI network nodes in rank order. We also identified the top 15 significant nodes for the ceRNAs identified according to degree centrality (DC) (P<0.05). Collectively, our analyses confirmed that the differential expression of certain ceRNAs, and their respective signaling pathways were associated with CAD.

Conclusions

Data arising from 11 GO and KEGG pathways, the top 15 PPI network nodes with the best connectivity rank, and the top 15 ceRNA network nodes, as determined by DC rank in CAD population, indicated that the differential expression of these ceRNAs plays a key role in the CAD. Our findings highlight new molecular mechanisms for CAD and provide new options for the development of therapeutic targets.

The emerging role of microRNAs in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection

The novel coronavirus disease 2019 (COVID-19) pandemic has imposed significant public health problems for the human populations worldwide after the 1918 influenza A virus (IVA) (H1N1) pandemic. Although numerous efforts have been made to unravel the mechanisms underlying the coronavirus, a notable gap remains in our perception of the COVID-19 pathogenesis. The innate and adaptive immune systems have a pivotal role in the fate of viral infections, such as COVID-19 pandemic. MicroRNAs (miRNAs) are known as short noncoding RNA molecules and appear as indispensable governors of almost any cellular means. Several lines of evidence demonstrate that miRNAs participate in essential mechanisms of cell biology, regulation of the immune system, and the onset and progression of numerous types of disorders. The immune responses to viral respiratory infections (VRIs), including influenza virus (IV), respiratory syncytial virus (RSV), and rhinovirus (RV), are correlated with the ectopic expression of miRNAs. Alterations of the miRNA expression in epithelial cells may contribute to the pathogenesis of chronic and acute airway infections. Hence, analyzing the role of these types of nucleotides in antiviral immune responses and the characterization of miRNA target genes might contribute to understanding the mechanisms of the interplay between the host and viruses, and in the future, potentially result in discovering therapeutic strategies for the prevention and treatment of acute COVID-19 infection. In this article, we present a general review of current studies concerning the function of miRNAs in different VRIs, particularly in coronavirus infection, and address all available therapeutic prospects to mitigate the burden of viral infections.

MicroRNAs and SARS-CoV-2 life cycle, pathogenesis, and mutations: biomarkers or therapeutic agents?

To date, proposed therapies and antiviral drugs have been failed to cure coronavirus disease 2019 (COVID-19) patients. However, at least two drug companies have applied for emergency use authorization with the United States Food and Drug Administration for their coronavirus vaccine candidates and several other vaccines are in various stages of development to determine safety and efficacy. Recently, some studies have shown the role of different human and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) microRNAs (miRNAs) in the pathophysiology of COVID-19. miRNAs are non-coding single-stranded RNAs, which are involved in several physiological and pathological conditions, such as cell proliferation, differentiation, and metabolism. They act as negative regulators of protein synthesis through binding to the 3' untranslated region (3' UTR) of the complementary target mRNA, leading to mRNA degradation or inhibition. The databases of Google Scholar, Scopus, PubMed, and Web of Science were searched for literature regarding the importance of miRNAs in the SARS-CoV-2 life cycle, pathogenesis, and genomic mutations. Furthermore, promising miRNAs as a biomarker or antiviral agent in COVID-19 therapy are reviewed.

COVID-19: fighting the invisible enemy with microRNAs

INTRODUCTION

The novel coronavirus (CoV) disease 2019 (COVID-19) is a viral infection that causes severe acute respiratory syndrome (SARS). It is believed that early reports of COVID-19 cases were noticed in December 2019 and soon after it became a global public health emergency. It is advised that COVID-19 transmits through human to human contact and in most cases, it remains asymptomatic. Several approaches are being utilized to control the outbreak of this fatal viral disease. microRNAs (miRNAs) are known signature therapeutic tool for the viral diseases; they are small non-coding RNAs that target the mRNAs to inhibit their post-transcriptional expression, therefore, impeding their functions, can serve as watchdogs or micromanagers in the cells.

AREAS COVERED

This review work delineated COVID-19 and its association with SARS and Middle East respiratory syndrome (MERS), the possible role of miRNAs in the pathogenesis of COVID-19, and therapeutic potential of miRNAs and their effective delivery to treat COVID-19.

EXPERT OPINION

This review highlighted the importance of various miRNAs and their potential role in fighting with this pandemic as therapeutic molecules utilizing nanotechnology.

Diabetes and COVID-19 risk: an miRNA perspective

Coronavirus disease 2019 (COVID-19) and diabetes outcomes (CORONADO) trial revealed that 10.6% of patients with diabetes mellitus hospitalized for COVID-19 (COVID-19) die within 7 days. Several studies from New York, Italy, and China confirm that patients with diabetes are at a much higher risk for mortality due to COVID-19. Besides respiratory illness, COVID-19 increases cardiac injury and diabetic ketoacidosis. In the absence of specific guidelines for the prevention and treatment of COVID-19 for patients with diabetes, they remain at higher risk and are more susceptible to COVID-19. Furthermore, there is a scarcity of basic knowledge on how diabetes affects pathogenesis of severe acute respiratory coronavirus (SARS-CoV-2) infection. In patients with diabetes, impaired glucose use alters metabolic and consequently biological processes instigating pathological remodeling, which has detrimental effects on cardiovascular systems. A majority of biological processes are regulated by noncoding microRNAs (miRNAs), which have emerged as a promising therapeutic candidate for several diseases. In consideration of the higher risk of mortality in patients with diabetes and COVID-19, novel diagnostic test and treatment strategy are urgently warranted in post-COVID-19 era. Here, we describe potential roles of miRNA as a biomarker and therapeutic candidate, especially for heart failure, in patients with diabetes and COVID-19.

Unravelling host-pathogen interactions: ceRNA network in SARS-CoV-2 infection (COVID-19)

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Bioinformatics analysis of mouse mRNA expression dataset for presumptive SARS-CoV-2 targets.

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Induction of ISGs-Isg15, Oasl1, Usp18 and Ddx58 with no marked changes in the expression of IFNs.

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No induction of ACE2 and TMPRSS2, raising implications for host factor limitations.

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Identification of ceRNA network including miR-124-3p, Ddx58, lncRNA (Gm26917) and circRNAs (Ppp1r10, C330019G07RiK).

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Virus regulates the expression of lnc and circRNAs, acting as sponges for miR-124-3p targeting Ddx58.

COVID-19 is a lurking calamitous disease caused by an unusual virus, SARS-CoV-2, causing massive deaths worldwide. Nonetheless, explicit therapeutic drugs or clinically approved vaccines are not available for COVID-19. Thus, a comprehensive research is crucially needed to decode the pathogenic tools, plausible drug targets, committed to the development of efficient therapy. Host-pathogen interactions via host cellular components is an emerging field of research in this respect. miRNAs have been established as vital players in host-virus interactions. Moreover, viruses have the capability to manoeuvre the host miRNA networks according to their own obligations. Besides protein coding mRNAs, noncoding RNAs might also be targeted in infected cells and viruses can exploit the host miRNA network via ceRNA effect. We have predicted a ceRNA network involving one miRNA (miR-124-3p), one mRNA (Ddx58), one lncRNA (Gm26917) and two circRNAs (Ppp1r10, C330019G07RiK) in SARS-CoV infected cells. We have identified 4 DEGs-Isg15, Ddx58, Oasl1, Usp18 by analyzing a mRNA GEO dataset. There is no notable induction of IFNs and IFN-induced ACE2, significant receptor responsible for S-protein binding mediated viral entry. Pathway enrichment and GO analysis conceded the enrichment of pathways associated with interferon signalling and antiviral-mechanism by IFN-stimulated genes. Further, we have identified 3 noncoding RNAs, playing as potential ceRNAs to the genes associated with immune mechanisms. This integrative analysis has identified noncoding RNAs and their plausible targets, which could effectively enhance the understanding of molecular mechanisms associated with viral infection. However, validation of these targets is further corroborated to determine their therapeutic efficacy.

The Role of MicroRNA in the Airway Surface Liquid Homeostasis

Mucociliary clearance, mediated by a coordinated function of cilia bathing in the airway surface liquid (ASL) on the surface of airway epithelium, protects the host from inhaled pathogens and is an essential component of the innate immunity. ASL is composed of the superficial mucus layer and the deeper periciliary liquid. Ion channels, transporters, and pumps coordinate the transcellular and paracellular movement of ions and water to maintain the ASL volume and mucus hydration. microRNA (miRNA) is a class of non-coding, short single-stranded RNA regulating gene expression by post-transcriptional mechanisms. miRNAs have been increasingly recognized as essential regulators of ion channels and transporters responsible for ASL homeostasis. miRNAs also influence the airway host defense. We summarize the most up-to-date information on the role of miRNAs in ASL homeostasis and host-pathogen interactions in the airway and discuss concepts for miRNA-directed therapy.

The impact of MicroRNAs (miRNAs) on the genotype of coronaviruses

Summar y. The beginning of 2020 has seen the emergence of COVID-19, an outbreak caused by a novel coronavirus, SARS-CoV-2, an important pathogen for humans. SARS-CoV-2 is an RNA virus containing 29891 nucleotides encoding 9889 amino acids. The genome is arranged as 5p-replicase (orf1/ab)-structural proteins [Spike (S) -Envelope (E) - Membrane (M) -Nucleocapsid (N)] -3. Viruses are obligate intracellular infectious agents that use the host cellular machinery to ensure their own fitness and survival. MicroRNAs (miRNA9) systems are potent post-transcriptional gene expression regulators that are important modulators of viral infections, and could play an important role in the treatment of viral infections. This review focuses to the genomic structure of coronaviruses, the functions of genomic proteins, the effects of micro RNA (miRNA) on virus replication and its pathogenesis.

A Circulating miRNA Signature for Stratification of Breast Lesions among Women with Abnormal Screening Mammograms

Although mammography is the gold standard for breast cancer screening, the high rates of false-positive mammograms remain a concern. Thus, there is an unmet clinical need for a non-invasive and reliable test to differentiate between malignant and benign breast lesions in order to avoid subjecting patients with abnormal mammograms to unnecessary follow-up diagnostic procedures. Serum samples from 116 malignant breast lesions and 64 benign breast lesions were comprehensively profiled for 2,083 microRNAs (miRNAs) using next-generation sequencing. Of the 180 samples profiled, three outliers were removed based on the principal component analysis (PCA), and the remaining samples were divided into training (n = 125) and test (n = 52) sets at a 70:30 ratio for further analysis. In the training set, significantly differentially expressed miRNAs (adjusted p < 0.01) were identified after correcting for multiple testing using a false discovery rate. Subsequently, a predictive classification model using an eight-miRNA signature and a Bayesian logistic regression algorithm was developed. Based on the receiver operating characteristic (ROC) curve analysis in the test set, the model could achieve an area under the curve (AUC) of 0.9542. Together, this study demonstrates the potential use of circulating miRNAs as an adjunct test to stratify breast lesions in patients with abnormal screening mammograms.

Emerging role of microRNA 628-5p as a novel biomarker for cancer and other diseases

MicroRNAs are a family of small, single-stranded RNAs that have key roles in regulating multiple signaling pathways within a cell. Studies have implicated aberrant expression of microRNAs in the development and progression of several pathologies including cancer. MicroRNAs are relatively stable and readily available in body fluids and tissues, making them desirable biomarkers for prognostic and diagnostic purposes in an array of diseases. MicroRNA 628 (5p/3p variants) is located in the 15q21.3 cancer-related region, and evidence suggests its association with various pathologies. The -5p mature variant, microRNA 628-5p, has been reported to be differentially expressed in various cancers, and its expression has been mostly associated with tumor suppression but there are few reports identifying its role in cancer progression. Several studies have also suggested its utility in diagnosis and prognosis of various cancers. Dysregulation of microRNA 628-5p has also been implicated in embryonal implantation defects, autism, immune modulation, myogenesis, cardiovascular disease, viral infection, and skeletal muscle repair. Here, we have provided a comprehensive review on available literature explaining the role of microRNA 628-5p as a potential cancer biomarker as well as briefly describe its function in other diseases and normal physiological conditions.

A Plasma Biomarker Panel of Four MicroRNAs for the Diagnosis of Prostate Cancer

Prostate cancer is diagnosed in over 1 million men every year globally, yet current diagnostic modalities are inadequate for identification of significant cancer and more reliable early diagnostic biomarkers are necessary for improved clinical management of prostate cancer patients. MicroRNAs (miRNAs) modulate important cellular processes/pathways contributing to cancer and are stably present in body fluids. In this study we profiled 372 cancer-associated miRNAs in plasma collected before (~60% patients) and after/during commencement of treatment (~40% patients), from age-matched prostate cancer patients and healthy controls, and observed elevated levels of 4 miRNAs - miR-4289, miR-326, miR-152-3p and miR-98-5p, which were validated in an independent cohort. The miRNA panel was able to differentiate between prostate cancer patients and controls (AUC = 0.88). Analysis of published miRNA transcriptomic data from clinical samples demonstrated low expression of miR-152-3p in tumour compared to adjacent non-malignant tissues. Overexpression of miR-152-3p increased proliferation and migration of prostate cancer cells, suggesting a role for this miRNA in prostate cancer pathogenesis, a concept that was supported by pathway analysis of predicted miR-152-3p target genes. In summary, a four miRNA panel, including miR-152-3p which likely targets genes with key roles in prostate cancer pathogenesis, has the potential to improve early prostate cancer diagnosis.

Middle East Respiratory Syndrome and Severe Acute Respiratory Syndrome: Current Therapeutic Options and Potential Targets for Novel Therapies

No specific antivirals are currently available for two emerging infectious diseases, Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS). A literature search was performed covering pathogenesis, clinical features and therapeutics, clinically developed drugs for repurposing and novel drug targets. This review presents current knowledge on the epidemiology, pathogenesis and clinical features of the SARS and MERS coronaviruses. The rationale for and outcomes with treatments used for SARS and MERS is discussed. The main focus of the review is on drug development and the potential that drugs approved for other indications provide for repurposing. The drugs we discuss belong to a wide range of different drug classes, such as cancer therapeutics, antipsychotics, and antimalarials. In addition to their activity against MERS and SARS coronaviruses, many of these approved drugs have broad-spectrum potential and have already been in clinical use for treating other viral infections. A wealth of knowledge is available for these drugs. However, the information in this review is not meant to guide clinical decisions, and any therapeutic described here should only be used in context of a clinical trial. Potential targets for novel antivirals and antibodies are discussed as well as lessons learned from treatment development for other RNA viruses. The article concludes with a discussion of the gaps in our knowledge and areas for future research on emerging coronaviruses.

miR-21a-5p Contributes to Porcine Hemagglutinating Encephalomyelitis Virus Proliferation via Targeting CASK-Interactive Protein1 In vivo and vitro

Porcine hemagglutinating encephalomyelitis virus (PHEV) is a highly neurovirulent coronavirus that can cause nervous symptoms in piglets with muscle tremors, hind limb paralysis, and nystagmus. Whether some factors affect virus replication and proliferation had not been fully understood in the course of nerve damage caused by PHEV infection. In recent years, some reports suggested that miRNA might play a key regulatory role in viral infection. In this study, we found the miR-21a-5p is notably up-regulated in the brains of mice and N2a cells infected with PHEV, and it down-regulated the expression of CASK-interactive protein1 (Caskin1) by directly targeting the 3′-UTR of Caskin1 using a Dual-Luciferase reporter assay. The over-expression of miR-21a-5p or Caskin1 knockdown in the host significantly contributes to PHEV proliferation. Conversely, the silencing of miR-21a-5p by miR-21a-5p inhibitors suppressed the virus proliferation. Taken together, our results indicate that Caskin1 is the direct target gene of miR-21a-5p, and it is advantageous to virus proliferation by down-regulating Caskin1. These findings may help in the development of strategies for therapeutic applications.

The role of microRNAs in respiratory viral infection: friend or foe?

MicroRNAs (miRNAs) have emerged as a class of regulatory RNAs in host-pathogen interactions. Aberrant miRNA expression seems to play a central role in the pathology of several respiratory viruses, promoting development and progression of infection. miRNAs may thus serve as therapeutic and prognostic factors for respiratory viral infectious disease caused by a variety of agents. We present a comprehensive review of recent findings related to the role of miRNAs in different respiratory viral infections and discuss possible therapeutic opportunities aiming to attenuate the burden of viral infections. Our review supports the emerging concept that cellular and viral-encoded miRNAs might be broadly implicated in human respiratory viral infections, with either positive or negative effects on virus life cycle. Copyright © 2016 John Wiley & Sons, Ltd.

MERS-CoV spike protein: Targets for vaccines and therapeutics

The disease outbreak caused by Middle East respiratory syndrome coronavirus (MERS-CoV) is still ongoing in the Middle East. Over 1700 people have been infected since it was first reported in September 2012. Despite great efforts, licensed vaccines or therapeutics against MERS-CoV remain unavailable. The MERS-CoV spike (S) protein is an important viral antigen known to mediate host-receptor binding and virus entry, as well as induce robust humoral and cell-mediated responses in humans during infection. In this review, we highlight the importance of the S protein in the MERS-CoV life cycle, summarize recent advances in the development of vaccines and therapeutics based on the S protein, and discuss strategies that can be explored to develop new medical countermeasures against MERS-CoV.

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A licensed vaccine or therapeutic against MERS-CoV remains unavailable to date.

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The S protein plays a pivotal role for virus entry and thus is an ideal target for vaccine and antiviral development.

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DNA vaccines expressing the S protein merit further development for potential human application.

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nAbs and peptides targeting the S protein needs to be evaluated in NHPs before clinical trials.

Middle East respiratory syndrome coronavirus "MERS-CoV": current knowledge gaps

The Middle East respiratory syndrome coronavirus (MERS-CoV) that causes a severe lower respiratory tract infection in humans is now considered a pandemic threat to the Gulf region. Since its discovery in 2012, MERS-CoV has reached 23 countries affecting about 1100 people, including a dozen children, and claiming over 400 lives. Compared to SARS (severe acute respiratory syndrome), MERS-CoV appears to kill more people (40% versus 10%), more quickly, and is especially more severe in those with pre-existing medical conditions. Most MERS-CoV cases (>85%) reported thus far have a history of residence in, or travel to the Middle East. The current epidemiology is characterised by slow and sustained transmission with occasional sparks. The dromedary camel is the intermediate host of MERS-CoV, but the transmission cycle is not fully understood. In this current review, we have briefly summarised the latest information on the epidemiology, clinical features, diagnosis, treatment and prevention of MERS-CoV especially highlighting the knowledge gaps in its transmission dynamics, diagnosis and preventive strategy.