miR-301a Regulates Inflammatory Response to Japanese Encephalitis Virus Infection via Suppression of NKRF Activity

WWP2 binds to NKRF, enhances the NF-κB signaling, and promotes malignant phenotypes of acute myeloid leukemia cells

Acute myeloid leukemia (AML) is one of the hematological malignancies with a high recurrence rate. WW domain-containing E3 ubiquitin protein ligase 2 (WWP2) is identified as a pivotal regulator of tumor progression. This study aimed to assess the possible role of WWP2 in AML. Analysis of the GEPIA database indicated an elevated WWP2 expression in AML. We established stable WWP2-overexpressed or WWP2-silenced cells using lentivirus loaded with cDNA encoding WWP2 mRNA or shRNA targeting WWP2. Notably, WWP2 overexpression facilitated cell proliferation and cell cycle progression, which was manifested as the increase of colony formation number, S-phase percentage and cell cycle related protein levels. As observed, WWP2 knockdown presented opposite effects, leading to inhibition of tumorigenicity. Strikingly, WWP2 knockdown induced apoptosis, accompanied by upregulation of pro-apoptosis proteins cleaved caspase-9, Bax and cleaved caspase-3 and downregulation of anti-apoptosis protein Bcl-2. Functionally, we further confirmed that WWP2 overexpression enhanced the NF-κB signaling and upregulated the levels of downstream genes, which may contribute to aggravating the development of AML. More importantly, by co-immunoprecipitation assay, we verified that WWP2 bound to NF-κB-repressing factor (NKRF) and promoted NKRF ubiquitylation. Dramatically, NKRF overexpression abolished the role of WWP2 in facilitating the process of AML. Overall, our observations confirm that WWP2 exerts a critical role in the tumorigenicity of AML, and NKRF is regarded as an essential factor in the WWP2-mediated AML progression. WWP2 may be proposed as a promising target of AML.

A Review of miRNA Regulation in Japanese Encephalitis (JEV) Virus Infection

Japanese encephalitis (JE) is a mosquito-borne disease that causes neuronal damage and inflammation of microglia, and in severe cases, it can be fatal. JE infection can resist cellular immune responses and survive in host cells. Japanese encephalitis virus (JEV) infects macrophages and peripheral blood lymphocytes. In addition to regulating biological signaling pathways, microRNAs in cells also influence virus-host interactions. Under certain circumstances, viruses can change microRNA production. These changes affect the replication and spread of the virus. Host miRNAs can contain viral pathogenicity by downregulating the antiviral immune response pathways. Simultaneous profiling of miRNA and messenger RNA (mRNA) could help us detect pathogenic factors, and dual RNA detection is possible. This work highlights important miRNAs involved in human JE infection. In this study, we have shown the important miRNAs that play significant roles in JEV infection. We found that during JEV infection, miRNA-155, miRNA-29b, miRNA-15b, miRNA-146a, miRNA-125b-5p, miRNA-30la, miRNA-19b-3p, and miRNA-124, cause upregulation of human genes whereas miRNA-432, miRNA-370, miRNA- 33a-5p, and miRNA-466d-3p are responsible for downregulation of human genes respectively. Further, these miRNAs are also responsible for the inflammatory effects. Although several other miRNAs critical to the JEV life cycle are yet unknown, there is currently no evidence for the role of miRNAs in persistence.

Regulation of microglia-mediated inflammation by host lncRNA Gm20559 upon flaviviral infection

BACKGROUND

Japanese Encephalitis Virus (JEV) and West Nile Viruses (WNV) are neurotropic flaviviruses which cause neuronal death and exaggerated glial activation in the central nervous system. Role of host long non coding RNAs in shaping microglial inflammation upon flavivirus infections has been unexplored. This study attempted to decipher the role of lncRNA Gm20559 in regulating microglial inflammatory response in context of flaviviruses.

METHODS

Antisense oligonucleotide LNA Gapmers designed against lncRNA Gm20559 and non-specific site (negative control) were used for Gm20559 knockdown in JEV and WNV-infected N9 microglial cells. Upon establishing successful Gm20559 knockdown, expression of various proinflammatory cytokines, chemokines, interferon-stimulated genes (ISGs) and RIG-I were checked by qRT-PCR and cytometric bead array. Western Blotting was done to analyse the phosphorylation level of various inflammatory markers and viral non-structural protein expression. Plaque Assays were employed to quantify viral titres in microglial supernatant upon knocking down Gm20559. Effect of microglial supernatant on HT22 neuronal cells was assessed by checking expression of apoptotic protein and viral non-structural protein by Western Blotting.

RESULTS

Upregulation in Gm20559 expression was observed in BALB/c pup brains, primary microglia as well as N9 microglia cell line upon both JEV and WNV infection. Knockdown of Gm20559 in JEV and WNV-infected N9 cell led to the reduction of major proinflammatory cytokines - IL-1β, IL-6, IP-10 and IFN-β. Inhibition of Gm20559 upon JEV infection in N9 microglia also led to downregulation of RIG-I and OAS-2, which was not the case in WNV-infected N9 microglia. Phosphorylation level of P38 MAPK was reduced in case of JEV-infected N9 microglia and not WNV-infected N9 microglia. Whereas phosphorylation of NF-κB pathway was unchanged upon Gm20559 knockdown in both JEV and WNV-infected N9 microglia. However, treating HT22 cells with JEV and WNV-infected microglial supernatant with and without Gm20559 could not trigger cell death or influence viral replication.

CONCLUSION

Knockdown studies on lncRNA Gm20559 suggests its pivotal role in maintaining the inflammatory milieu of microglia in flaviviral infection by modulating the expression of various pro-inflammatory cytokines. However, Gm20559-induced increased microglial proinflammatory response upon flavivirus infection fails to trigger neuronal death.

High-throughput sequencing-based Detection of Japanese encephalitis virus and its effect on micro ribonucleic acid

it was to explore the mechanism of Japanese encephalitis virus (JEV) and micro ribonucleic acid (miRNA) under high-throughput sequencing. 20 experimental mice, with good growth status and no disease infection, were selected. The cells used in the experiment included mouse microglial cell line (BV2), mouse neuroblastoma cell line (NA), and mouse brain endothelial cell line (bEnd.3). JEV titration was performed with JEV-infected cells, ribonucleic acid (RNA) in the cells was extracted, and finally the miRNA high-throughput sequencing data was analyzed. Agarose gel electrophoresis showed that the 28S and 18S electrophoresis bands were bright. Among the miRNAs detected in mouse brain tissues, 2986 were down-regulated and 1251 were up-regulated. Among miRNAs detected in NA cells, 4238 the decreasing expression and 2356 were expressed increasingly. In reducing miRNA expression, 1 multiplicity of infection (MOI) of P3 strain infection was more significant than 0.1 MOI. 10 miRNAs with significantly decreasing expression were miR-466d-3p, miR-381-3p, miR-540-3p, miR-466a-3p, miR-467a-3p, miR-574-5p, miR-199a-5p, miR-467a-5p, miR-674-5p, and miR-376b-3p. These were all obviously down-regulated in JEV-infected BV2, NA, and bEnd.3 neurons. High-throughput sequencing of JEV-infected mouse brain tissues and mouse neuronal cells found that JEV infection led to down-regulation of overall miRNA expression in host cells.

Controlling viral inflammatory lesions by rebalancing immune response patterns

In this review, we discuss a variety of immune modulating approaches that could be used to counteract tissue-damaging viral immunoinflammatory lesions which typify many chronic viral infections. We make the point that in several viral infections the lesions can be largely the result of one or more aspects of the host response mediating the cell and tissue damage rather than the virus itself being directly responsible. However, within the reactive inflammatory lesions along with the pro-inflammatory participants there are also other aspects of the host response that may be acting to constrain the activity of the damaging components and are contributing to resolution. This scenario should provide the prospect of rebalancing the contributions of different host responses and hence diminish or even fully control the virus-induced lesions. We identify several aspects of the host reactions that influence the pattern of immune responsiveness and describe approaches that have been used successfully, mainly in model systems, to modulate the activity of damaging participants and which has led to lesion control. We emphasize examples where such therapies are, or could be, translated for practical use in the clinic to control inflammatory lesions caused by viral infections.

H3K27me3 of Rnf19a promotes neuroinflammatory response during Japanese encephalitis virus infection

Histone methylation is an important epigenetic modification that affects various biological processes, including the inflammatory response. In this study, we found that infection with Japanese encephalitis virus (JEV) leads to an increase in H3K27me3 in BV2 microglial cell line, primary mouse microglia and mouse brain. Inhibition of H3K27me3 modification through EZH2 knockdown and treatment with EZH2 inhibitor significantly reduces the production of pro-inflammatory cytokines during JEV infection, which suggests that H3K27me3 modification plays a crucial role in the neuroinflammatory response caused by JEV infection. The chromatin immunoprecipitation-sequencing (ChIP-sequencing) assay revealed an increase in H3K27me3 modification of E3 ubiquitin ligases Rnf19a following JEV infection, which leads to downregulation of Rnf19a expression. Furthermore, the results showed that Rnf19a negatively regulates the neuroinflammatory response induced by JEV. This is achieved through the degradation of RIG-I by mediating its ubiquitination. In conclusion, our findings reveal a novel mechanism by which JEV triggers extensive neuroinflammation from an epigenetic perspective.

PBMC MicroRNAs: Promising Biomarkers for the Differential Diagnosis of COVID-19 Patients with Abnormal Coagulation Indices

MicroRNAs, or miRNAs, may involve in coagulation and inflammation pathways caused by severe Coronavirus disease (COVID-19). Accordingly, this attempt was made to explore the behavior of peripheral blood mononuclear cells (PBMCs) miRNAs as effective biomarkers to diagnose COVID-19 patients with normal and abnormal coagulation indices. We selected the targeted miRNAs (miR-19a-3p, miR-223-3p, miR-143-5p, miR-494-3p and miR-301a-5p) according to previous reports, whose PBMC levels were then determined by real-time PCR. Receiver operating characteristic (ROC) curve was obtained to clarify the diagnostic potency of studied miRNAs. The differentially expressed miRNA profiles and corresponding biological activities were predicted in accordance with bioinformatics data. Targeted miRNAs' expression profiles displayed a significant difference between COVID-19 subjects with normal and abnormal coagulation indices. Moreover, the average miR-223-3p level expressed in COVID-19 cases with normal coagulation indices was significantly lower than that in healthy controls. Based on data from ROC analysis, miR-223-3p and miR-494-3p are promising biomarkers to distinguish the COVID-19 cases with normal or abnormal coagulation indices. Bioinformatics data highlighted the prominent role of selected miRNAs in the inflammation and TGF-beta signaling pathway. The differences existed in the expression profiles of selected miRNAs between the groups introduced miR-494-3p and miR-223-3p as potent biomarkers to prognosis the incidence of COVID-19.

Placental microRNA methylome signatures may serve as biomarkers and therapeutic targets for prenatally opioid-exposed infants with neonatal opioid withdrawal syndrome

Introduction: The neonate exposed to opioids in utero faces a constellation of withdrawal symptoms postpartum commonly called neonatal opioid withdrawal syndrome (NOWS). The incidence of NOWS has increased in recent years due to the opioid epidemic. MicroRNAs (miRNAs) are small non-coding RNA molecules that play a crucial role in gene regulation. Epigenetic variations in microRNAs (miRNAs) and their impact on addiction-related processes is a rapidly evolving area of research. Methods: The Illumina Infinium Methylation EPIC BeadChip was used to analyze DNA methylation levels of miRNA-encoding genes in 96 human placental tissues to identify miRNA gene methylation profiles as-sociated with NOWS: 32 from mothers whose prenatally opioid-exposed infants required pharmacologic management for NOWS, 32 from mothers whose prenatally opioid-exposed infants did not require treat-ment for NOWS, and 32 unexposed controls. Results: The study identified 46 significantly differentially methylated (FDR p-value ≤ 0.05) CpGs associated with 47 unique miRNAs, with a receiver operating characteristic (ROC) area under the curve (AUC) ≥0.75 including 28 hypomethylated and 18 hypermethylated CpGs as potentially associated with NOWS. These dysregulated microRNA methylation patterns may be a contributing factor to NOWS pathogenesis. Conclusion: This is the first study to analyze miRNA methylation profiles in NOWS infants and illustrates the unique role miRNAs might have in diagnosing and treating the disease. Furthermore, these data may provide a step toward feasible precision medicine for NOWS babies as well.

A nuclear NKRF interacting long noncoding RNA controls EBV eradication and suppresses tumor progression in natural killer/T-cell lymphoma

Long intergenic noncoding RNAs (lincRNAs) are differentially expressed in EBV-infected cells and play an essential role in tumor progression. Molecular pathogenesis of lincRNAs in EBV-driven natural killer T cell lymphoma (NKTCL) remains unclear. Here we investigated the ncRNA profile using high-throughput RNA sequencing data of 439 lymphoma samples and screened out LINC00486, whose downregulation was further validated by quantitative real-time polymerase chain reaction in EBV-encoded RNA (EBER)-positive lymphoma, particularly NKTCL. Both in vitro and in vivo studies revealed the tumor suppressive function of LINC00486 through inhibiting tumor cell growth and inducing G0/G1 cell cycle arrest. As mechanism of action, LINC00486 specifically interacted with NKRF to abrogate its binding with phosphorylated p65, activated NF-κB/TNF-α signaling and subsequently enhanced EBV eradication. Solute carrier family 1 member 1 (SLC1A1), upregulated and mediated the glutamine-addiction and tumor progression in NKTCL, was negatively correlated with the expression of NKRF. NKRF specifically bound to the promoter and transcriptionally downregulated the expression of SLC1A1, as evidenced by Chromatin Immunoprecipitation (ChIP) and luciferase assay. Collectively, LINC00486 functioned as a tumor suppressor and counteracted EBV infection in NKTCL. Our study improved the knowledge of EBV-driven oncogenesis in NKTCL and provided the clinical rationale of EBV eradication in anti-cancer treatment.

Short-Chain Fatty Acids in the Microbiota-Gut-Brain Axis: Role in Neurodegenerative Disorders and Viral Infections

The gut-brain axis (GBA) is the umbrella term to include all bidirectional communication between the brain and gastrointestinal (GI) tract in the mammalian body. Evidence from over two centuries describes a significant role of GI microbiome in health and disease states of the host organism. Short-chain fatty acids (SCFAs), mainly acetate, butyrate, and propionate that are the physiological forms of acetic acid, butyric acid, and propionic acid respectively, are GI bacteria derived metabolites. SCFAs have been reported to influence cellular function in multiple neurodegenerative diseases (NDDs). In addition, the inflammation modulating properties of SCFAs make them suitable therapeutic candidates in neuroinflammatory conditions. This review provides a historical background of the GBA and current knowledge of the GI microbiome and role of individual SCFAs in central nervous system (CNS) disorders. Recently, a few reports have also identified the effects of GI metabolites in the case of viral infections. Among these viruses, the flaviviridae family is associated with neuroinflammation and deterioration of CNS functions. In this context, we additionally introduce SCFA based mechanisms in different viral pathogenesis to understand the former's potential as agents against flaviviral disease.

Involvement of host microRNAs in flavivirus-induced neuropathology: An update

Flaviviruses are a spectrum of vector-borne RNA viruses that cause potentially severe diseases in humans including encephalitis, acute-flaccid paralysis, cognitive disorders and foetal abnormalities. Japanese encephalitis virus (JEV), Zika virus (ZIKV), West Nile virus (WNV) and Dengue virus (DENV) are globally emerging pathogens that lead to epidemics and outbreaks with continued transmission to newer geographical areas over time. In the past decade, studies have focussed on understanding the pathogenic mechanisms of these viruses in a bid to alleviate their disease burden. MicroRNAs (miRNAs) are short single-stranded RNAs that have emerged as master-regulators of cellular gene expression. The dynamics of miRNAs within a cell have the capacity to modulate hundreds of genes and, consequently, their physiological manifestation. Increasing evidence suggests their role in host response to disease and infection including cell survival, intracellular viral replication and immune activation. In this review, we aim to comprehensively update published evidence on the role of miRNAs in host cells infected with the common neurotropic flaviviruses, with an increased focus on neuropathogenic mechanisms. In addition, we briefly cover therapeutic advancements made in the context of miRNA-based antiviral strategies.

miR-451a Regulates Neuronal Apoptosis by Modulating 14-3-3ζ-JNK Axis upon Flaviviral Infection

Japanese Encephalitis Virus (JEV)/West Nile Virus (WNV)-induced encephalitis, although observed in selective cases, is associated with fatal consequences ranging from decline in cognitive abilities among recovered patients to coma/death. Loss of neuronal cells following viral infection-induced neuronal death imposes significant challenge to the central nervous system (CNS) homeostasis eventually resulting in loss of CNS tissue integrity and poor disease outcome in patients. In our present study, we aim to evaluate the role played by miRNA in modulating neuronal death upon neurotropic flaviviral infections. Infection of neuronal cell line resulted in upregulation of miR-451a abundance. Upon its upregulation, miR-451a has been demonstrated to target 3′-UTR of 14-3-3ζ transcript culminating into downregulation of 14-3-3ζ at the protein level. In response to 14-3-3ζ protein depletion in the cytosol upon flavivirus infection, increased phosphorylation of JNK protein has been shown to take place thus paving way for the cell to undergo apoptosis. Reversal of virus-induced miR-451a-upregulation helped abrogate neuronal apoptosis which is accompanied by a restoration of 14-3-3ζ protein and phosphorylated-JNK abundance to its normal level. Our findings hence provide a possible therapeutic target for preventing JEV/WNV-induced neuronal apoptosis thus improving disease outcome in flaviviral infection-associated encephalitis.

IMPORTANCE Neuronal infection by JEV/WNV culminates into neuronal cell death thus contributing to signs and symptoms exhibited by patients that suffer from and that have recovered from JEV/WNV-induced encephalitis. In the present study we have evaluated the role of miRNA in promoting flavivirus-induced neuronal apoptosis. miR-451a has been demonstrated to promote neuronal cell death by targeting 14-3-3ζ protein function. The function of miR-451a in modulating neuronal physiology toward self-destruction has been shown to be independent of its effect upon the virus infection life cycle. The 14-3-3ζ transcript upon being targeted by miR-451a promotes JNK phosphorylation hence culminating into neuronal death by activation of apoptotic machinery. Inhibition of miR-451a upon neuronal infection by JEV/WNV helped reduce apoptotic machinery activation hence providing us with possible future therapeutic strategy in ameliorating flavivirus-induced neurological manifestations and overall disease burden in terms of morbidity.

Methylenedioxy Piperamide-Derived Compound D5 Regulates Inflammatory Cytokine Secretion in a Culture of Human Glial Cells

Neuroinflammation is the cornerstone of most neuronal disorders, particularly neurodegenerative diseases. During the inflammatory process, various pro-inflammatory cytokines, chemokines, and enzymes—such as interleukin 1-β (IL1-β), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), inducible nitric oxide synthases (iNOS), inhibitory kappa kinase (IKK), and inducible nitric oxide (NO)—are over-expressed in response to every stimulus. Methods: In the present study, we focused on the anti-neuroinflammatory efficacy of (2E,4E)-N,5-bis(benzo[d][1,3]dioxol-5-yl)penta-2,4-dienamide, encoded D5. We investigated the efficacy of D5 on the upstream and downstream products of inflammatory pathways in CHME3 and SVG cell lines corresponding to human microglia and astrocytes, respectively, using various in silico, in vitro, and in situ techniques. Results: The results showed that D5 significantly reduced the level of pro-inflammatory cytokines by up-regulating PPAR-γ expression and suppressing IKK-β, iNOS, NO production, and NF-κB activation in inflamed astrocytes (SVG) and microglia (CHME3) after 24 h of incubation. The data demonstrated remarkably higher efficacy of D5 compared to ASA (Aspirin) in reducing NF-κB-dependent neuroinflammation. Conclusions: We observed that the functional-group alteration had an extreme influence on the levels of druggability and the immunomodulatory properties of two analogs of piperamide, D5, and D4 ((2E,4E)-5-(benzo[d][1,3]dioxol-5-yl)-N-(4-(hydroxymethyl)phenyl)penta-2,4-dienamide)). The present study suggested D5 as a potential anti-neuroinflammatory agent for further in vitro, in vivo, and clinical investigations.

Regulatory Role of Host MicroRNAs in Flaviviruses Infection

MicroRNAs (miRNAs) are small non-coding RNA that affect mRNA abundance or translation efficiency by binding to the 3′UTR of the mRNA of the target gene, thereby participating in multiple biological processes, including viral infection. Flavivirus genus consists of small, positive-stranded, single-stranded RNA viruses transmitted by arthropods, especially mosquitoes and ticks. The genus contains several globally significant human/animal pathogens, such as Dengue virus, Japanese encephalitis virus, West Nile virus, Zika virus, Yellow fever virus, Tick-borne encephalitis virus, and Tembusu virus. After flavivirus invades, the expression of host miRNA changes, exerting the immune escape mechanism to create an environment conducive to its survival, and the altered miRNA in turn affects the life cycle of the virus. Accumulated evidence suggests that host miRNAs influence flavivirus replication and host–virus interactions through direct binding of viral genomes or through virus-mediated host transcriptome changes. Furthermore, miRNA can also interweave with other non-coding RNAs, such as long non-coding RNA and circular RNA, to form an interaction network to regulate viral replication. A variety of non-coding RNAs produced by the virus itself exert similar function by interacting with cellular RNA and viral RNA. Understanding the interaction sites between non-coding RNA, especially miRNA, and virus/host genes will help us to find targets for antiviral drugs and viral therapy.

Cerebrospinal Fluid Extracellular Vesicles with Distinct Properties in Autoimmune Encephalitis and Herpes Simplex Encephalitis

Encephalitis mediated by autoantibodies against neuronal antigens and herpes simplex encephalitis (HSE) are seemingly separate causes of encephalopathy in adults. Autoimmune encephalitis (AE) is autoimmune in origin, and herpes simplex encephalitis is infectious. The purpose of this study was to examine the role of cerebrospinal fluid (CSF) exosomes from patients with antibody-positive AE and HSE. Towards this, exosomes were isolated from CSF from 13 patients with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis, 11 patients with anti-gamma-aminobutyric acid-B (GABAB) receptor encephalitis, 9 patients with anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis, and 8 patients with anti-contactin-associated protein-like 2 (CASPR2) encephalitis, and 12 control individuals negative of antibodies against neuronal autoantigens. There were ten miRNAs highly expressed in patients with anti-NMDAR encephalitis compared to those in control subjects. Eight miRNAs were found to be lower expressed in anti-NMDAR encephalitis CSF-derived exosomes. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enriched by AE differential expressed exosomic miRNAs demonstrated that AE-related exosomic miRNAs may participate as a feedback regulation in cancer development. In addition, the exosome concentration in CSF of 9 HSE patients was significantly higher compared to those from 9 HSV( −) patients. This observation was consistent with the results that exosome concentration was found to be higher in the animal model which was inoculated intranasally with HSV-1 compared to controls. Furthermore, western blot demonstrated that the subunits of NMDAR, GABA_BR, and AMPAR were detected highly expressed in exosomes derived from sera of HSV-1-treated animal model compared to controls. More importantly, exosomes isolated from CSF of HSE patients contained higher expression levels of two miRNAs encoded by HSV, miR-H2-3p, and miR-H4-3p compared to those from HSV( −) patients. In summary, HSV may trigger brain autoimmunity in HSE by presentation of surface autoantigens via exosomes.

Involvement of host microRNAs in flavivirus-induced neuropathology: An update

Flaviviruses are a spectrum of vector-borne RNA viruses that cause potentially severe diseases in humans including encephalitis, acute-flaccid paralysis, cognitive disorders and foetal abnormalities. Japanese encephalitis virus (JEV), Zika virus (ZIKV), West Nile virus (WNV) and Dengue virus (DENV) are globally emerging pathogens that lead to epidemics and outbreaks with continued transmission to newer geographical areas over time. In the past decade, studies have focussed on understanding the pathogenic mechanisms of these viruses in a bid to alleviate their disease burden. MicroRNAs (miRNAs) are short single-stranded RNAs that have emerged as master-regulators of cellular gene expression. The dynamics of miRNAs within a cell have the capacity to modulate hundreds of genes and, consequently, their physiological manifestation. Increasing evidence suggests their role in host response to disease and infection including cell survival, intracellular viral replication and immune activation. In this review, we aim to comprehensively update published evidence on the role of miRNAs in host cells infected with the common neurotropic flaviviruses, with an increased focus on neuropathogenic mechanisms. In addition, we briefly cover therapeutic advancements made in the context of miRNA-based antiviral strategies.

Involvement of RIG-I Pathway in Neurotropic Virus-Induced Acute Flaccid Paralysis and Subsequent Spinal Motor Neuron Death

Poliomyelitis-like illness is a common clinical manifestation of neurotropic viral infections. Functional loss and death of motor neurons often lead to reduced muscle tone and paralysis, causing persistent motor sequelae among disease survivors. Despite several reports demonstrating the molecular basis of encephalopathy, the pathogenesis behind virus-induced flaccid paralysis remained largely unknown. The present study for the first time aims to elucidate the mechanism responsible for limb paralysis by studying clinical isolates of Japanese encephalitis virus (JEV) and Chandipura virus (CHPV) responsible for causing acute flaccid paralysis (AFP) in vast regions of Southeast Asia and the Indian subcontinent. An experimental model for studying virus-induced AFP was generated by intraperitoneal injection of 10-day-old BALB/c mice. Progressive decline in motor performance of infected animals was observed, with paralysis being correlated with death of motor neurons (MNs). Furthermore, we demonstrated that upon infection, MNs undergo an extrinsic apoptotic pathway in a RIG-I-dependent fashion via transcription factors pIRF-3 and pIRF-7. Both gene-silencing experiments using specific RIG-I-short interfering RNA and in vivo morpholino abrogated cellular apoptosis, validating the important role of pattern recognition receptor (PRR) RIG-I in MN death. Hence, from our experimental observations, we hypothesize that host innate response plays a significant role in deterioration of motor functioning upon neurotropic virus infections. IMPORTANCE Neurotropic viral infections are an increasingly common cause of immediate or delayed neuropsychiatric sequelae, cognitive impairment, and movement disorders or, in severe cases, death. Given the highest reported disability-adjusted life years and mortality rate worldwide, a better understanding of molecular mechanisms for underlying clinical manifestations like AFP will help in development of more effective tools for therapeutic solutions.

The inhibitory role of benzo-dioxole-piperamide on the phosphorylation process as an NF-Kappa B silencer

NF-κB contributes to the biosynthesis of various chemokines, cytokines, and enzymes. It plays many crucial roles in the upstream neuroinflammatory pathways. Briefly, the inhibitory IkB subunit is cleaved and phosphorylated by the IKK-α/β enzyme. It leads to the activation and translocation of the NF-κB (p50/p65) complex into the nucleus. Subsequently, the activated NF-κB interacts with the genomic DNA and contributes to expressing various proinflammatory cytokines. In the present study, we developed a novel NF-κB inhibitor encoded (D5) and investigated the efficacy of our druggable compound through several in silico, in vitro, and in situ analysis. The results demonstrated that D5 not only inhibited the mRNA expression of the IKK-α/β enzyme (around 86-96% suppression rate for both cell lines at 12 and 24 h time frames) but also by interacting to the active site of the mentioned kinase (dock score -6.14 and binding energy -23.60 kcal/mol) reduced the level of phosphorylated IkB-α in the cytosol around 96-99% and p65 subunit in the nucleus around 73-90% (among all groups in 12 and 24 h time points). Additionally, the results indicated that D5 suppressed the NF-κB target mRNA levels of TNF-α and IL-6 in a total average of around 92%. Overall, The results demonstrated that D5 in a considerably lower concentration than Dis (0.71 µM vs. 52.73 µM) showed significantly higher inhibitory efficacy on NF-κB translocation approx. 200-300%. The results suggested D5 as a potent NF-κB silencer, but further investigations are required to validate our outcomes.

Pathogenicity and virulence of Japanese encephalitis virus: Neuroinflammation and neuronal cell damage

Thousands of human deaths occur annually due to Japanese encephalitis (JE), caused by Japanese encephalitis virus. During the virus infection of the central nervous system, reactive gliosis, uncontrolled inflammatory response, and neuronal cell death are considered as the characteristic features of JE. To date, no specific treatment has been approved to overcome JE, indicating a need for the development of novel therapies. In this article, we focused on basic biological mechanisms in glial (microglia and astrocytes) and neuronal cells that contribute to the onset of neuroinflammation and neuronal cell damage during Japanese encephalitis virus infection. We also provided comprehensive knowledge about anti-JE therapies tested in clinical or pre-clinical settings, and discussed recent therapeutic strategies that could be employed for JE treatment. The improved understanding of JE pathogenesis might lay a foundation for the development of novel therapies to halt JE.Abbreviations AKT: a serine/threonine-specific protein kinase; AP1: activator protein 1; ASC: apoptosis-associated speck-like protein containing a CARD; ASK1: apoptosis signal-regulated kinase 1; ATF3/4/6: activating transcription factor 3/4/6; ATG5/7: autophagy-related 5/7; BBB: blood-brain barrier; Bcl-3/6: B-cell lymphoma 3/6 protein; CCL: C-C motif chemokine ligand; CCR2: C-C motif chemokine receptor 2; CHOP: C/EBP homologous protein; circRNA: circular RNA; CNS: central nervous system; CXCL: C-X-C motif chemokine ligand; dsRNA: double-stranded RNA; EDEM1: endoplasmic reticulum degradation enhancer mannosidase alpha-like 1; eIF2-ɑ: eukaryotic initiation factor 2 alpha; ER: endoplasmic reticulum; ERK: extracellular signal-regulated kinase; GRP78: 78-kDa glucose-regulated protein; ICAM: intercellular adhesion molecule; IFN: interferon; IL: interleukin; iNOS: inducible nitric oxide synthase; IRAK1/2: interleukin-1 receptor-associated kinase 1/2; IRE-1: inositol-requiring enzyme 1; IRF: interferon regulatory factor; ISG15: interferon-stimulated gene 15; JE: Japanese encephalitis; JEV: Japanese encephalitis virus; JNK: c-Jun N-terminal kinase; LAMP2: lysosome-associated membrane protein type 2; LC3-I/II: microtubule-associated protein 1 light chain 3-I/II; lncRNA: long non-coding RNA; MAPK: mitogen-activated protein kinase; miR/miRNA: microRNA; MK2: mitogen-activated protein kinase-activated protein kinase 2; MKK4: mitogen-activated protein kinase kinase 4; MLKL: mixed-linage kinase domain-like protein; MMP: matrix metalloproteinase; MyD88: myeloid differentiation factor 88; Nedd4: neural precursor cell-expressed developmentally downregulated 4; NF-κB: nuclear factor kappa B; NKRF: nuclear factor kappa B repressing factor; NLRP3: NLR family pyrin domain containing 3; NMDAR: N-methyl-D-aspartate receptor; NO: nitric oxide; NS2B/3/4: JEV non-structural protein 2B/3/4; P: phosphorylation. p38: mitogen-activated protein kinase p38; PKA: protein kinase A; PAK4: p21-activated kinase 4; PDFGR: platelet-derived growth factor receptor; PERK: protein kinase R-like endoplasmic reticulum kinase; PI3K: phosphoinositide 3-kinase; PTEN: phosphatase and tensin homolog; Rab7: Ras-related GTPase 7; Raf: proto-oncogene tyrosine-protein kinase Raf; Ras: a GTPase; RIDD: regulated IRE-1-dependent decay; RIG-I: retinoic acid-inducible gene I; RIPK1/3: receptor-interacting protein kinase 1/3; RNF11/125: RING finger protein 11/125; ROS: reactive oxygen species; SHIP1: SH2-containing inositol 5' phosphatase 1; SOCS5: suppressor of cytokine signaling 5; Src: proto-oncogene tyrosine-protein kinase Src; ssRNA = single-stranded RNA; STAT: signal transducer and activator of transcription; TLR: toll-like receptor; TNFAIP3: tumor necrosis factor alpha-induced protein 3; TNFAR: tumor necrosis factor alpha receptor; TNF-α: tumor necrosis factor-alpha; TRAF6: tumor necrosis factor receptor-associated factor 6; TRIF: TIR-domain-containing adapter-inducing interferon-β; TRIM25: tripartite motif-containing 25; VCAM: vascular cell adhesion molecule; ZO-1: zonula occludens-1.

Polarization of Type 1 Macrophages Is Associated with the Severity of Viral Encephalitis Caused by Japanese Encephalitis Virus and Dengue Virus

Infection with flaviviruses causes mild to severe diseases, including viral hemorrhagic fever, vascular shock syndrome, and viral encephalitis. Several animal models explore the pathogenesis of viral encephalitis, as shown by neuron destruction due to neurotoxicity after viral infection. While neuronal cells are injuries caused by inflammatory cytokine production following microglial/macrophage activation, the blockade of inflammatory cytokines can reduce neurotoxicity to improve the survival rate. This study investigated the involvement of macrophage phenotypes in facilitating CNS inflammation and neurotoxicity during flavivirus infection, including the Japanese encephalitis virus, dengue virus (DENV), and Zika virus. Mice infected with different flaviviruses presented encephalitis-like symptoms, including limbic seizure and paralysis. Histology indicated that brain lesions were identified in the hippocampus and surrounded by mononuclear cells. In those regions, both the infiltrated macrophages and resident microglia were significantly increased. RNA-seq analysis showed the gene profile shifting toward type 1 macrophage (M1) polarization, while M1 markers validated this phenomenon. Pharmacologically blocking C-C chemokine receptor 2 and tumor necrosis factor-α partly retarded DENV-induced M1 polarization. In summary, flavivirus infection, such as JEV and DENV, promoted type 1 macrophage polarization in the brain associated with encephalitic severity.

The role of the X chromosome in infectious diseases

Many infectious diseases in humans present with a sex bias. This bias arises from a combination of environmental factors, hormones and genetics. In this study, we review the contribution of the X chromosome to the genetic factor associated with infectious diseases. First, we give an overview of the X-linked genes that have been described in the context of infectious diseases and group them in four main pathways that seem to be dysregulated in infectious diseases: nuclear factor kappa-B, interleukin 2 and interferon γ cascade, toll-like receptors and programmed death ligand 1. Then, we review the infectious disease associations in existing genome-wide association studies (GWAS) from the GWAS Catalog and the Pan-UK Biobank, describing the main associations and their possible implications for the disease. Finally, we highlight the importance of including the X chromosome in GWAS analysis and the importance of sex-specific analysis.

Retinoic Acid-Inducible Gene I-Like Receptors Activate Snail To Limit RNA Viral Infections

Retinoic acid-inducible gene I-like receptors (RLRs) are important cytosolic pattern recognition receptors (PRRs) that sense viral RNA before mounting a response leading to the activation of type I IFNs. Several viral infections induce epithelial-mesenchymal transition (EMT), even as its significance remains unclear. Here, we show that EMT or an EMT-like process is a general response to viral infections. Our studies identify a previously unknown mechanism of regulation of an important EMT-transcription factor (EMT-TF) Snail during RNA viral infections and describe its possible implication. RNA viral infections, poly(I·C) transfection, and ectopic expression of RLR components induced Snail levels, indicating that RLR pathway could regulate its expression. Detailed examination using mitochondrial antiviral signaling protein knockout (MAVS-KO) cells established that MAVS is essential in this regulation. We identified two interferon-stimulated response elements (ISREs) in the SNAI1 promoter region and demonstrated that they are important in its transcriptional activation by phosphorylated IRF3. Increasing the levels of Snail activated RLR pathway and dramatically limited replication of the RNA viruses dengue virus, Japanese encephalitis virus (JEV), and vesicular stomatitis virus, pointing to their antiviral functions. Knockdown of Snail resulted in a considerable increase in the JEV titer, validating its antiviral functions. Finally, transforming growth factor β-mediated IFNB activation was dependent on Snail levels, confirming its important role in type I IFN activation. Thus, EMT-TF Snail is transcriptionally coregulated with type I IFN by RLRs and, in turn, promotes the RLR pathway, further strengthening the antiviral state in the cell. Our work identified an interesting mechanism of regulation of Snail that demonstrates potential coregulation of multiple innate antiviral pathways triggered by RLRs. Identification of antiviral functions of Snail also provides an opportunity to expand the sphere of RLR signaling. IMPORTANCE RLRs sense viral genomic RNA or the double-stranded RNA intermediates and trigger the activation of type I IFNs. Snail transcription factor, commonly associated with epithelial-mesenchymal transition (EMT), has been reported to facilitate EMT in several viral infections. Many of these reports are based on oncoviruses, leading to the speculation that EMT induced during infection is an important factor in the oncogenesis triggered by these infections. However, our studies reveal that EMT or EMT-like processes during viral infections have important functions in antiviral response. We have characterized a new mechanism of transcriptional regulation of Snail by IRF3 through interferon-stimulated response elements in their promoters, and this finding could have importance in nonviral contexts as well. We also identify that EMT-TF Snail promotes antiviral status of the infected cells through the RLR pathway. This study characterizes a new regulatory mechanism of activation of Snail and establishes its unidentified function in antiviral response.

Selenium-deficient diet induces necroptosis in the pig brain by activating TNFR1 via mir-29a-3p

Selenium (Se) deficiency is one of the crucial factors related to nervous system disease and necroptosis. MicroRNAs (miRNAs) play vital roles in regulating necroptosis. However, the mechanism of Se deficiency-induced necroptosis in the pig brain tissue and the role that miRNAs play in this process are unclear. Therefore, in this study, in vitro and pig models of Se deficiency were replicated, and electron microscopy, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot assays were performed. The results showed that brain cells typically undergo necrotic changes, and that Se deficiency suppresses mir-29a-3p, which increases the levels of TNFRSF1A (TNFR1). Subsequently, a distinct increase in the necroptosis markers (RIPK1, RIPK3, and MLKL) and an evident decrease in caspase 8 was observed. And the expression of 10 selenoproteins was decreased. Moreover, the in vitro experiments showed that the expression of mir-29a-3p decreased as the Se content in the medium decreased and the application of an mir-29a-3p inhibitor increased the number of necrotic cells and the accumulation of ROS, and these effects were inhibited by necrostatin-1 (Nec-1) and N-acetyl-cysteine (NAC), respectively. Taken together, we proved that Se deficiency induced necroptosis both in vitro and in vivo through the targeted regulation of TNFR1 by mir-29a-3p in the pig brain.

Pathobiology of Japanese encephalitis virus infection

Japanese encephalitis virus (JEV) is a flavivirus, spread by the bite of carrier Culex mosquitoes. The subsequent disease caused is Japanese encephalitis (JE), which is the leading global cause of virus-induced encephalitis. The disease is predominant in the entire Asia-Pacific region with the potential of global spread. JEV is highly neuroinvasive with symptoms ranging from mild fever to severe encephalitis and death. One-third of JE infections are fatal, and half of the survivors develop permanent neurological sequelae. Disease prognosis is determined by a series of complex and intertwined signaling events dictated both by the virus and the host. All flaviviruses, including JEV replicate in close association with ER derived membranes by channelizing the protein and lipid components of the ER. This leads to activation of acute stress responses in the infected cell-oxidative stress, ER stress, and autophagy. The host innate immune and inflammatory responses also enter the fray, the components of which are inextricably linked to the cellular stress responses. These are especially crucial in the periphery for dendritic cell maturation and establishment of adaptive immunity. The pathogenesis of JEV is a combination of direct virus induced neuronal cell death and an uncontrolled neuroinflammatory response. Here we provide a comprehensive review of the JEV life cycle and how the cellular stress responses dictate the pathobiology and resulting immune response. We also deliberate on how modulation of these stress pathways could be a potential strategy to develop therapeutic interventions, and define the persisting challenges.

miR-21a-5p Promotes Inflammation following Traumatic Spinal Cord Injury through Upregulation of Neurotoxic Reactive Astrocyte (A1) Polarization by Inhibiting the CNTF/STAT3/Nkrf Pathway

Reactive astrocytes are implicated in traumatic spinal cord injury (TSCI). Interestingly, naïve astrocytes can easily transform into neurotoxic reactive astrocytes (A1s) with inflammatory stimulation. Previous studies demonstrated that microRNA(miR)-21a-5p was up-regulated in spinal cord tissue after TSCI; however, it is not clear whether this affected reactive astrocyte polarization. Here, we aim to detect the effects of miR-21a-5p on the induction of A1 formation and the underlying mechanisms. Our study found that the expression of miR-21a-5p was significantly increased while that of Cntfr α was decreased, since naïve astrocytes transformed into A1s 3 days post-TSCI; the binding site between miR-21a-5p and Cntfr α was further confirmed in astrocytes. After treatment with CNTF, the levels of A1 markers decreased while that of A2 increased. The expression of A1 markers significantly decreased with the downregulation of miR-21a-5p, while Cntfr α siRNA treatment caused the opposite both in vitro and in vivo. To summarize, miR-21a-5p/Cntfr α promotes A1 induction and might enhance the inflammatory process of TSCI; furthermore, we identified, for the first time, the effect and potential mechanism by which CNTF inhibits naïve astrocytes transformation into A1s. Collectively, our findings demonstrate that targeting miR-21a-5p represents a prospective therapy for promoting the recovery of TSCI.

Bta-miR-101 suppresses BEFV replication via targeting NKRF

MicroRNAs (miRNAs), as a kind of small noncoding RNAs, have been proved to play a regulatory role in virus infection. However, the role and mechanism of cellular miRNAs in bovine transient fever virus (BEFV) infection are largely unknown. In the present study, we found that bta-miR-101 was significantly up-regulated in the Madin-Darby Bovine Kidney (MDBK) cells upon BEFV infection. Notably, bta-miR-101 mimic dramatically inhibited BEFV replication, while bta-miR-101 inhibitor facilitated BEFV replication, suggesting that bta-miR-101 acted as an anti-viral host factor restraining BEFV replication. Subsequently, NF-κB repressing factor (NKRF) was identified as a target gene of bta-miR-101 by dual luciferase reporter assay, and bta-miR-101 mimic significantly down-regulated expression of NKRF, while bta-miR-101 inhibitor up-regulated its expression, respectively. Furthermore, NKRF could induce apoptosis, and favored the replication of BEFV. Finally, bta-miR-101 inhibited BEFV-induced apoptosis via targeting NKRF to suppress virus replication. In general, our study provides a novel mechanism for bta-miR-101 to exert its antiviral function, which provides a theoretical basis for the development of antiviral strategy.

MicroRNA-301a-3p increases oxidative stress, inflammation and apoptosis in ox-LDL-induced HUVECs by targeting KLF7

Arteriosclerotic cardiovascular disease is an inflammatory disease of ischemia or endothelial dysfunction caused by atherosclerosis, thereby causing high mortality. The viability and apoptosis of human umbilical vein endothelial cells (HUVECs) following oxidized low-density lipoprotein (ox-LDL) induction or transfection was detected by Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis. MicroRNA (miR)-301a-3p and Krueppel-like factor 7 (KLF7) mRNA expression was determined by reverse transcription-quantitative PCR (RT-qPCR). The levels of monocyte chemoattractant protein-1 (MCP-1) and IL-6, activities of reactive oxygen species and superoxide dismutase and lactate dehydrogenase leakage were analyzed by respective commercial assay kits. The protein expression of IL-6, MCP-1, Bcl2, Bax, poly (ADP-ribose) polymerase (PARP), cleaved PARP, pro-caspase3 and cleaved caspase-3 was detected by western blotting. miR-301a-3p expression is highly expressed in ox-LDL-induced HUVECs. miR-301a-3p is also a target of KLF7. Inhibition of miR-301a-3p suppressed oxidative stress, inflammation and apoptosis in ox-LDL-induced HUVECs, which was reversed by KLF7 inhibition. In conclusion, miR-301a-3p promotes oxidative stress, inflammation and apoptosis in ox-LDL-induced HUVECs via decreasing KLF7 expression.

Altered microRNAs in cerebrospinal fluid exosomes in paraneoplastic and autoimmune encephalitis: A possible feedback in cancer development

AIMS

The purpose of this study was to examine the role of cerebrospinal fluid (CSF) exosomes from patients with paraneoplastic and autoimmune encephalitis (AE).

MAIN METHODS

Towards this, microRNA profiling in the exosomes which were isolated from cerebrospinal fluid of 12 patients with anti-N-methyl-d-aspartate (NMDA) receptor encephalitis, 12 patients with anti-gamma-aminobutyric acid-B (GABAB) receptor encephalitis, 12 patients with anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis, and 12 patients with anti-contactin-associated protein-like 2 (CASPR2) encephalitis, and 12 control individuals negative of antibodies against neuronal auto-antigens. Selected findings were validated with quantitative RT-PCR. DIANA-mirPath was chosen for bioinformatic analysis.

KEY FINDINGS

There were ten miRNAs higher expressed in AE patients with anti-NMDAR encephalitis compared to those in healthy controls. Further, eight miRNAs were found to be lower expressed in anti-NMDAR encephalitis CSF derived exosomes. In addition, Endometrial cancer, p53 signaling pathway, Non-small cell lung cancer, Small cell lung cancer, Transcriptional misregulation in cancer, Basal cell carcinoma, Acute myeloid leukemia, Renal cell carcinoma, Colorectal cancer, Choline metabolism in cancer, Melanoma, Pancreatic cancer, Prostate cancer, Ras signaling pathway, Glioma, Pathways in cancer, and Proteoglycans in cancer (all p < 0.01) were significantly enriched in differentially expressed miRNAs.

SIGNIFICANCES

Exosomes expressing specific miRNAs in antibody positive AE may participate as a feedback regulation in cancer development.

DHA attenuated Japanese Encephalitis virus infection-induced neuroinflammation and neuronal cell death in cultured rat Neuron/glia

Japanese Encephalitis Virus (JEV) is a neurotropic virus and its Central Nervous System (CNS) infection causes fatal encephalitis with high mortality and morbidity. Microglial activation and consequences of bystander damage appear to be the dominant mechanisms for Japanese Encephalitis and complications. Docosahexaenoic acid (DHA), an essential fatty acid and a major component of brain cell membranes, possesses additional biological activities, including anti-apoptosis, anti-inflammation, and neuroprotection. Through this study, we have provided experimental evidence showing the anti-inflammatory, neuroprotective, and anti-viral effects of DHA against JEV infection in rat Neuron/glia cultures. By Neuron/glia and Neuron cultures, DHA protected against neuronal cell death upon JEV infection and reduced JEV amplification. In Neuron/glia and Microglia cultures, the effects of DHA were accompanied by the downregulation of pro-inflammatory M1 microglia, upregulation of anti-inflammatory M2 microglia, and reduction of neurotoxic cytokine expression, which could be attributed to its interference in the Toll-Like Receptor (TLR), Mitogen-Activated Protein Kinase (MAPK), and Interferon/Janus Kinase/Signal Transducers and Activators of Transcription (Stat), along with the NF-κB, AP-1, and c-AMP Response Element Binding Protein (CREB) controlled transcriptional programs. Parallel anti-inflammatory effects against JEV infection were duplicated by G Protein-Coupled Receptor (GPR120) and GPR40 agonists and a reversal of DHA-mediated anti-inflammation was seen in the presence of GPR120 antagonist, while the GPR40 was less effectiveness. Since increasing evidence indicates its neuroprotection against neurodegenerative diseases, DHA is a proposed anti-inflammatory and neuroprotective candidate for the treatment of neuroinflammation-accompanied viral pathogenesis such as Japanese Encephalitis.

Neuroinflammation in Ischemic Stroke: Focus on MicroRNA-mediated Polarization of Microglia

Ischemic stroke is one of the most common causes of death and disability worldwide. Neuroinflammation is a major pathological event involved in the process of ischemic injury and repair. In particular, microglia play a dual role in neuroinflammation. During the acute phase of stroke onset, M2 microglia are the dominant phenotype and exert protective effects on neuronal cells, whereas permanent M1 microglia contribute to prolonged inflammation and are detrimental to brain tissue. Emerging evidence indicates that microRNAs (miRNAs) may have regulatory effects on microglia-associated inflammation. Thus, we briefly reviewed the dynamic response of microglia after a stroke and assessed how specific miRNAs affect the behavior of reactive microglia. We concluded that miRNAs may be useful novel therapeutic targets to improve stroke outcomes and modulate neuroinflammation.

Long noncoding RNA MARL regulates antiviral responses through suppression miR-122-dependent MAVS downregulation in lower vertebrates

Increasing evidence suggests important roles for long noncoding RNAs (lncRNAs) as new gene modulators involved in various biological processes. However, the function roles of lncRNAs in lower vertebrates are still unknown. Here, we firstly identify a lncRNA, named MAVS antiviral-related lncRNA (MARL), as a key regulator for antiviral immunity in teleost fish. The results indicate that fish MAVS play essential roles in host antiviral responses and inhibition of Siniperca chuatsi rhabdovirus (SCRV) replication. miR-122 reduces MAVS expression and suppress MAVS-mediated antiviral responses, which may help viruses evade host antiviral responses. Further, MARL functions as a competing endogenous RNA (ceRNA) for miR-122 to control protein abundance of MAVS, thereby inhibiting SCRV replication and promoting antiviral responses. Our data not only shed new light on understanding the function role of lncRNA in biological processes in lower vertebrates, but confirmed the hypothesis that ceRNA regulatory networks exist widely in vertebrates.

Increasing evidence indicates that lncRNAs participate in the regulation of various biological processes, especially innate and adaptive immunity. However, the relationship between lncRNAs and host antiviral responses remains largely unknown, particularly in lower vertebrates. Our results provided the first direct evidence that a lncRNA, termed MAVS antiviral-related lncRNA (MARL), acts as a key regulator for antiviral immunity in lower vertebrates. lncRNAs have been identified to function as competing endogenous RNAs (ceRNAs) and cross-talk with mRNAs by competing shared for miRNAs. Such ceRNAs regulate the distribution of miRNA molecules on their targets and thereby apply an additional level of post-transcriptional regulation. In our study, MARL functions as a ceRNA for miR-122 to control protein abundance of fish MAVS, thereby inhibiting virus replication and promoting antiviral responses. This is the first study to demonstrate ceRNA regulatory networks existing in lower vertebrates, which can provide new insights into understanding the effects of lncRNAs on host-virus interactions.

Recent advances in understanding Japanese encephalitis

Japanese encephalitis (JE) is a clinical manifestation of the brain inflammation caused by JE virus (JEV). This virus imparts permanent neurological damage, thus imposing a heavy burden on public health and society. Neuro-inflammation is the hallmark of JEV infection. The prolonged pro-inflammatory response is due primarily to microglial activation, which eventually leads to severe encephalitis. A continual effort is going on in the scientific community toward an understanding of cellular and molecular factors that are involved in JEV neuro-invasion and inflammatory processes. This review not only gives a comprehensive update on the recent advances on understanding virus structure and mechanisms of pathogenesis but also briefly discusses crucial unresolved issues. We also highlight challenging areas of research that might open new avenues for controlling virus-induced neuro-inflammation.