Japanese encephalitis virus inhibits superinfection of Zika virus in cells by the NS2B protein.

Superinfection exclusion (SIE) is a phenomenon in which a preexisting infection prevents a secondary infection. SIE has been described for several flaviviruses, such as West Nile virus vs Nhumirim virus and Dengue virus vs yellow fever virus. Zika virus (ZIKV) is an emerging flavivirus posing threats to human health. The SIE between ZIKV and Japanese encephalitis virus (JEV) is investigated in this study. Our results demonstrate for the first time that JEV inhibits ZIKV infection in both mammalian and mosquito cells, whether co-infects or subsequently infects after ZIKV. The exclusion effect happens at the stage of ZIKV RNA replication. Further studies show that the expression of JEV NS2B protein is sufficient to inhibit the replication of ZIKV, and the outer membrane region of NS2B (46-103 aa) is responsible for this SIE. JEV infection and NS2B expression also inhibit the infection of the vesicular stomatitis virus. In summary, our study characterized a SIE caused by JEV NS2B. This may have potential applications in the prevention and treatment of ZIKV or other RNA viruses.IMPORTANCEThe reemerged Zika virus (ZIKV) has caused severe symptoms in humans and poses a continuous threat to public health. New vaccines or antiviral agents need to be developed to cope with possible future pandemics. In this study, we found that infection of Japanese encephalitis virus (JEV) or expression of NS2B protein well inhibited the replication of ZIKV. It is worth noting that both the P3 strain and vaccine strain SA14-14-2 of JEV exhibited significant inhibitory effects on ZIKV. Additionally, the JEV NS2B protein also had an inhibitory effect on vesicular stomatitis virus infection, suggesting that it may be a broad-spectrum antiviral factor. These findings provide a new way of thinking about the prevention and treatment of ZIKV.

Crystal structure of the ATPase domain of porcine circovirus type 2 Rep protein.

PCV2 belongs to the genus Circovirus in the family Circoviridae, whose genome is replicated by rolling circle replication (RCR). PCV2 Rep is a multifunctional enzyme that performs essential functions at multiple stages of viral replication. Rep is responsible for nicking and ligating single-stranded DNA and unwinding double-stranded DNA (dsDNA). However, the structure and function of the Rep are still poorly understood, which significantly impedes viral replication research. This study successfully resolved the structure of the PCV2 Rep ATPase domain (PRAD) using X-ray crystallography. Homologous structure search revealed that Rep belonged to the superfamily 3 (SF3) helicase, and multiple conserved residues were identified during sequence alignment with SF3 family members. Simultaneously, a hexameric PRAD model was generated for analysing characteristic structures and sites. Mutation of the conserved site and measurement of its activity showed that the hallmark motifs of the SF3 family influenced helicase activity by affecting ATPase activity and ß-hairpin just caused the loss of helicase activity. The structural and functional analyses of the PRAD provide valuable insights for future research on PCV2 replication and antiviral strategies.

Oral administration of PEDV-dissolved Alg-CS gel induces high and sustained mucosal immunity in mice.

Porcine epidemic diarrhea (PED) is a serious disease in piglets that leads to high mortality. An effective measure that provides higher IgA levels in the intestine and milk is required to decrease losses. Porcine epidemic diarrhea virus (PEDV) was dissolved in calcium alginate (Alg) and combined with chitosan (CS) via electrostatic interactions between cationic chitosan and anionic alginate to create a porous gel (Alg-CS+PEDV). The gel was used to immunize mice orally or in combination with subcutaneous injections of inactivated PEDV vaccine. At 12 and 24 days after immunization, levels of IgA and IgG in Alg-CS+PEDV were higher than with normal PEDV oral administration. At 24 days after immunization, the concentration of IFN-γ in Alg-CS+PEDV was higher than with normal PEDV oral administration. Furthermore, oral administration combining subcutaneous immunization induced higher levels of IgG and IgA than oral administration alone. Our study provides a new method for the preparation and administration of oral vaccines to achieve enhanced mucosal immunity against PEDV.

A review on the recycling of spent lithium iron phosphate batteries.

Lithium iron phosphate (LFP) batteries have gained widespread recognition for their exceptional thermal stability, remarkable cycling performance, non-toxic attributes, and cost-effectiveness. However, the increased adoption of LFP batteries has led to a surge in spent LFP battery disposal. Improper handling of waste LFP batteries could result in adverse consequences, including environmental degradation and the mismanagement of valuable secondary resources. This paper presents a comprehensive examination of waste LFP battery treatment methods, encompassing a holistic analysis of their recycling impact across five dimensions: resources, energy, environment, economy, and society. The recycling of waste LFP batteries is not only crucial for reducing the environmental pollution caused by hazardous components but also enables the valuable components to be efficiently recycled, promoting resource utilization. This, in turn, benefits the sustainable development of the energy industry, contributes to economic gains, stimulates social development, and enhances employment rates. Therefore, the recycling of discarded LFP batteries is both essential and inevitable. In addition, the roles and responsibilities of various stakeholders, including governments, corporations, and communities, in the realm of waste LFP battery recycling are also scrutinized, underscoring their pivotal engagement and collaboration. Notably, this paper concentrates on surveying the current research status and technological advancements within the waste LFP battery lifecycle, and juxtaposes their respective merits and drawbacks, thus furnishing a comprehensive evaluation and foresight for future progress.

Crystal structure of the dimerized of porcine circovirus type II replication-related protein Rep'.

Porcine circovirus type 2 (PCV2) can cause porcine circovirus-associated disease (PCVAD), which causes significant economic losses to the global pig industry annually. There are no effective antiviral drugs used to control and treat PCV2, and prevention is mainly obtained through vaccination. PCV2 genome replicates through the rolling circle replication (RCR) mechanism involving Rep and Rep', so analyzing the holistic structure of Rep and Rep' will help us better understand the replication process of PCV2. However, there are no reports on the integral structure of Rep' and Rep, which seriously hinders the research of the viral replication. By using the x-ray diffraction method, the structure of the Rep' dimer was resolved by us in this study. Structural analysis revealed that Rep' is a dimer formed by the interaction of the C-terminal domain. The two Rep' form a positively charged groove, which may play an essential role in the viral binding of dsDNA. Together, this study help to understand the replication process of the virus and may also provide new insights into the development of antiviral drugs.

The Japanese Encephalitis Virus NS1' Protein Inhibits Type I IFN Production by Targeting MAVS.

Japanese encephalitis virus (JEV) is a mosquito-borne Flavivirus that causes severe neurologic disease in humans. NS1' is a NS1-related protein only reported in the Japanese encephalitis serogroup members of Flavivirus It is produced through programmed -1 ribosomal frameshift in NS2A. Our previous study demonstrated that JEV NS1' could antagonize type I IFN (IFN-I) production, but the mechanism is still unclear. In the current study, we found that JEV NS1' inhibits the expression of MAVS, and knockdown of MAVS hampers inhibition of IFN-ß induction by NS1', suggesting that JEV NS1' inhibits IFN-I production by targeting MAVS. This finding is further supported by the result of the in vivo assay that showed the similar mortality caused by NS1'-deficient virus and its wild type virus in MAVS-deficient mice. Based on our previous sequencing results of noncoding RNA in JEV-infected cells, microRNA-22 (miR-22) was identified to be a key regulator for MAVS expression during JEV infection. Furthermore, we demonstrated that JEV NS1' could induce the expression of miR-22 by increasing the binding of transcriptional factors, CREB and c-Rel, to the promoter elements of miR-22. Taken together, our results reveal a novel mechanism by which JEV NS1' antagonizes host MAVS by regulating miR-22, thereby inhibiting the IFN-I production and facilitating viral replication.

Structural Characterization of the Helicase nsp10 Encoded by Porcine Reproductive and Respiratory Syndrome Virus.

Currently, an effective therapeutic treatment for porcine reproductive and respiratory syndrome virus (PRRSV) remains elusive. PRRSV helicase nsp10 is an important component of the replication transcription complex that plays a crucial role in viral replication, making nsp10 an important target for drug development. Here, we report the first crystal structure of full-length nsp10 from the arterivirus PRRSV, which has multiple domains: an N-terminal zinc-binding domain (ZBD), a 1B domain, and helicase core domains 1A and 2A. Importantly, our structural analyses indicate that the conformation of the 1B domain from arterivirus nsp10 undergoes a dynamic transition. The polynucleotide substrate channel formed by domains 1A and 1B adopts an open state, which may create enough space to accommodate and bind double-stranded RNA (dsRNA) during unwinding. Moreover, we report a unique C-terminal domain structure that participates in stabilizing the overall helicase structure. Our biochemical experiments also showed that deletion of the 1B domain and C-terminal domain significantly reduced the helicase activity of nsp10, indicating that the four domains must cooperate to contribute to helicase function. In addition, our results indicate that nidoviruses contain a conserved helicase core domain and key amino acid sites affecting helicase function, which share a common mechanism of helicase translocation and unwinding activity. These findings will help to further our understanding of the mechanism of helicase function and provide new targets for the development of antiviral drugs.IMPORTANCE Porcine reproductive and respiratory syndrome virus (PRRSV) is a major respiratory disease agent in pigs that causes enormous economic losses to the global swine industry. PRRSV helicase nsp10 is a multifunctional protein with translocation and unwinding activities and plays a vital role in viral RNA synthesis. Here, we report the first structure of full-length nsp10 from the arterivirus PRRSV at 3.0-Å resolution. Our results show that the 1B domain of PRRSV nsp10 adopts a novel open state and has a unique C-terminal domain structure, which plays a crucial role in nsp10 helicase activity. Furthermore, mutagenesis and structural analysis revealed conservation of the helicase catalytic domain across the order Nidovirales (families Arteriviridae and Coronaviridae). Importantly, our results will provide a structural basis for further understanding the function of helicases in the order Nidovirales.

Crystal Structure of the Dimerized N Terminus of Porcine Circovirus Type 2 Replicase Protein Reveals a Novel Antiviral Interface.

Two replicase (Rep) proteins, Rep and Rep', are encoded by porcine circovirus (PCV) ORF1; Rep is a full ORF1 transcript, and Rep' is a truncated transcript generated by splicing. These two proteins are crucial for the rolling-circle replication (RCR) of PCV. The N-terminal sequences of Rep and Rep' are identical and interact to form homo- or heterodimers. The three types of dimers perform different functions during replication. A structural examination of the interfacing termini has not been performed. In this study, a crystal structure of dimerized Rep protein N termini was resolved at 2.7 Å. The dimerized protein was maintained by nine intermolecular hydrogen bonds and 15 pairs of hydrophobic interactions. The amino acid residue Ile37 participates in 11 of the hydrophobic interactions, mostly with its side chain. To find the predominant sites for protein dimerization and virus replication, a series of mutant proteins and virus replicons were generated by alanine substitution. Of all the single amino acid substitutions, the mutation at Ile37 showed the greatest effect on protein dimerization and virus replication. A double mutation at Leu35 and Ile37 almost eliminated protein dimerization and had the greatest negative effect on virus replication. These studies demonstrate that Leu35 and Ile37 are the most important residues for protein dimerization and are crucial for virus replication. Our results also show that PCV replication can be decreased by disrupting the dimerization of Rep or Rep' at the N terminus, suggesting that the structural interface responsible for dimerization offers a promising antiviral target.IMPORTANCE Porcine circovirus type 2 (PCV2) is one of the most economically damaging pathogens affecting the swine industry. Although vaccines have been available for more than 10 years, the virus still remains prevalent. More effective strategies for disease prevention are clearly required. The Rep and Rep' proteins of the virus have identical N-terminal regions that interact with each other, allowing the formation of homo- or heterodimers. The heterodimer has crucial functions during different stages of viral replication. Here, we resolved the crystal structure of the Rep (Rep') dimerization domain. The individual residues involved in the intermolecular interaction were visualized in the protein structure, and several interactions were verified by mutant analysis. Our studies show that disrupting the interaction decreases viral replication, thus revealing a new target for the design of antiviral agents.

Development and application of a monoclonal-antibody-based blocking ELISA for detection of Japanese encephalitis virus NS1 antibodies in swine.

Japanese encephalitis virus (JEV) is a zoonotic pathogen transmitted by Culex mosquitoes and is the leading cause of viral encephalitis in humans. JEV infection of swine, which are the main amplifying hosts for JEV, can cause reproductive failure in sows; in boars it can cause testitis and infertility. The prevalence of JEV in swine is a continuous threat to human health. A practical diagnostic method for monitoring JEV infection in swine herds is essential for control of the disease in both swine and humans. Here, we have identified a high-affinity anti-JEV NS1 monoclonal antibody (mAb) by indirect ELISA and utilized it for the development of a blocking ELISA (bELISA). The optimal NS1 protein coating concentration (2 µg/mL) and mAb working concentration (1 µg/mL) were determined by checkerboard titration. One hundred ten JEV-antibody-negative serum samples were used to establish 34.03% inhibition as the cutoff value for a negative result. By the bELISA, seroconversion in 80% of newly JEV-vaccinated pigs was detected by 7 days post-immunization, while by the commercial envelope-protein-based iELISA, seroconversion was detected in 20% of the newly vaccinated pigs. We found 98.7% agreement between the bELISA and the commercial iELISA when we tested 157 field samples using both methods. From an epidemiological survey of swine serum collected between 2014 and 2016, we found that the average JEV seropositive rate in unvaccinated commodity pigs was 8.1%, and in vaccinated boars and sows, it was 67.6%.

Activation of neuronal N-methyl-D-aspartate receptor plays a pivotal role in Japanese encephalitis virus-induced neuronal cell damage.

BACKGROUND: Overstimulation of glutamate receptors, especially neuronal N-methyl-D-aspartate receptor (NMDAR), mediates excitatory neurotoxicity in multiple neurodegenerative diseases. However, the role of NMDAR in the regulation of Japanese encephalitis virus (JEV)-mediated neuropathogenesis remains undisclosed. The primary objective of this study was to understand the function of NMDAR to JEV-induced neuronal cell damage and inflammation in the central nervous system. METHODS: The effect of JEV-induced NMDAR activation on the progression of Japanese encephalitis was evaluated using the primary mouse neuron/glia cultures and a mouse model of JEV infection. A high-affinity NMDAR antagonist MK-801 was employed to block the activity of NMDAR both in vitro and in vivo. The subsequent impact of NMDAR blockade was assessed by examining the neuronal cell death, glutamate and inflammatory cytokine production, and JEV-induced mice mortality. RESULTS: JEV infection enhanced the activity of NMDAR which eventually led to increased neuronal cell damage. The data obtained from our in vitro and in vivo assays demonstrated that NMDAR blockade significantly abrogated the neuronal cell death and inflammatory response triggered by JEV infection. Moreover, administration of NMDAR antagonist protected the mice from JEV-induced lethality. CONCLUSION: NMDAR plays an imperative role in regulating the JEV-induced neuronal cell damage and neuroinflammation. Thus, NMDAR targeting may constitute a captivating approach to rein in Japanese encephalitis.

Japanese Encephalitis Virus NS5 Inhibits Type I Interferon (IFN) Production by Blocking the Nuclear Translocation of IFN Regulatory Factor 3 and NF-κB.

The type I interferon (IFN) response is part of the first-line defense against viral infection. To initiate replication, viruses have developed powerful evasion strategies to counteract host IFN responses. In the present study, we found that the Japanese encephalitis virus (JEV) NS5 protein could inhibit double-stranded RNA (dsRNA)-induced IFN-ß expression in a dose-dependent manner. Our data further demonstrated that JEV NS5 suppressed the activation of the IFN transcriptional factors IFN regulatory factor 3 (IRF3) and NF-κB. However, there was no defect in the phosphorylation of IRF3 and degradation of IκB, an upstream inhibitor of NF-κB, upon NS5 expression, indicating a direct inhibition of the nuclear localization of IRF3 and NF-κB by NS5. Mechanistically, NS5 was shown to interact with the nuclear transport proteins KPNA2, KPNA3, and KPNA4, which competitively blocked the interaction of KPNA3 and KPNA4 with their cargo molecules, IRF3 and p65, a subunit of NF-κB, and thus inhibited the nuclear translocation of IRF3 and NF-κB. Furthermore, overexpression of KPNA3 and KPNA4 restored the activity of IRF3 and NF-κB and increased the production of IFN-ß in NS5-expressing or JEV-infected cells. Additionally, an upregulated replication level of JEV was shown upon KPNA3 or KPNA4 overexpression. These results suggest that JEV NS5 inhibits the induction of type I IFN by targeting KPNA3 and KPNA4.IMPORTANCE JEV is the major cause of viral encephalitis in South and Southeast Asia, with high mortality. However, the molecular mechanisms contributing to the severe pathogenesis are poorly understood. The ability of JEV to counteract the host innate immune response is potentially one of the mechanisms responsible for JEV virulence. Here we demonstrate the ability of JEV NS5 to interfere with the dsRNA-induced nuclear translocation of IRF3 and NF-κB by competitively inhibiting the interaction of IRF3 and NF-κB with nuclear transport proteins. Via this mechanism, JEV NS5 suppresses the induction of type I IFN and the antiviral response in host cells. These findings reveal a novel strategy for JEV to escape the host innate immune response and provide new insights into the pathogenesis of JEV.

Drug Repurposing for Japanese Encephalitis Virus Infection by Systems Biology Methods.

Japanese encephalitis is a zoonotic disease caused by the Japanese encephalitis virus (JEV). It is mainly epidemic in Asia with an estimated 69,000 cases occurring per year. However, no approved agents are available for the treatment of JEV infection, and existing vaccines cannot control various types of JEV strains. Drug repurposing is a new concept for finding new indication of existing drugs, and, recently, the concept has been used to discover new antiviral agents. Identifying host proteins involved in the progress of JEV infection and using these proteins as targets are the center of drug repurposing for JEV infection. In this study, based on the gene expression data of JEV infection and the phenome-wide association study (PheWAS) data, we identified 286 genes that participate in the progress of JEV infection using systems biology methods. The enrichment analysis of these genes suggested that the genes identified by our methods were predominantly related to viral infection pathways and immune response-related pathways. We found that bortezomib, which can target these genes, may have an effect on the treatment of JEV infection. Subsequently, we evaluated the antiviral activity of bortezomib using a JEV-infected mouse model. The results showed that bortezomib can lower JEV-induced lethality in mice, alleviate suffering in JEV-infected mice and reduce the damage in brains caused by JEV infection. This work provides an agent with new indication to treat JEV infection.

MicroRNA-33a-5p Modulates Japanese Encephalitis Virus Replication by Targeting Eukaryotic Translation Elongation Factor 1A1.

UNLABELLED: Japanese encephalitis virus (JEV) is a typical mosquito-borne flavivirus responsible for acute encephalitis and meningitis in humans. However, the molecular mechanism for JEV pathogenesis is still unclear. MicroRNAs (miRNAs) are small noncoding RNAs that act as gene regulators. They are directly or indirectly involved in many cellular functions owing to their ability to target mRNAs for degradation or translational repression. However, how cellular miRNAs are regulated and their functions during JEV infection are largely unknown. In the present study, we found that JEV infection downregulated the expression of endogenous cellular miR-33a-5p. Notably, artificially transfecting with miR-33a-5p mimics led to a significant decrease in viral replication, suggesting that miR-33a-5p acts as a negative regulator of JEV replication. A dual-luciferase reporter assay identified eukaryotic translation elongation factor 1A1 (EEF1A1) as one of the miR-33a-5p target genes. Our study further demonstrated that EEF1A1 can interact with the JEV proteins NS3 and NS5 in replicase complex. Through this interaction, EEF1A1 can stabilize the components of viral replicase complex and thus facilitates viral replication during JEV infection. Taken together, these results suggest that miR-33a-5p is downregulated during JEV infection, which contributes to viral replication by increasing the intracellular level of EEF1A1, an interaction partner of JEV NS3 and NS5. This study provides a better understanding of the molecular mechanisms of JEV pathogenesis. IMPORTANCE: MiRNAs are critical regulators of gene expression that utilize sequence complementarity to bind to and modulate the stability or translation efficiency of target mRNAs. Accumulating data suggest that miRNAs regulate a wide variety of molecular mechanisms in the host cells during viral infections. JEV, a neurotropic flavivirus, is one of the major causes of acute encephalitis in humans worldwide. The roles of cellular miRNAs during JEV infections are widely unexplored. The present study explores a novel role of miR-33a-5p as a negative regulator of JEV replication. We found EEF1A1 as a direct target of miR-33a-5p. We also demonstrated that EEF1A1 interacts with and stabilize the components of JEV replicase complex, which positively regulates JEV replication. These findings suggest a new insight into the molecular mechanism of JEV pathogenesis and provide a possible therapeutic entry point for viral encephalitis.

MicroRNA-15b Modulates Japanese Encephalitis Virus-Mediated Inflammation via Targeting RNF125.

Japanese encephalitis virus (JEV) can target CNS and cause neuroinflammation that is characterized by profound neuronal damage and concomitant microgliosis/astrogliosis. Although microRNAs (miRNAs) have emerged as a major regulatory network with profound effects on inflammatory response, it is less clear how they regulate JEV-induced inflammation. In this study, we found that miR-15b is involved in modulating the JEV-induced inflammatory response. The data demonstrate that miR-15b is upregulated during JEV infection of glial cells and mouse brains. In vitro overexpression of miR-15b enhances the JEV-induced inflammatory response, whereas inhibition of miR-15b decreases it. Mechanistically, ring finger protein 125 (RNF125), a negative regulator of RIG-I signaling, is identified as a direct target of miR-15b in the context of JEV infection. Furthermore, inhibition of RNF125 by miR-15b results in an elevation in RIG-I levels, which, in turn, leads to a higher production of proinflammatory cytokines and type I IFN. In vivo knockdown of virus-induced miR-15b by antagomir-15b restores the expression of RNF125, reduces the production of inflammatory cytokines, attenuates glial activation and neuronal damage, decreases viral burden in the brain, and improves survival in the mouse model. Taken together, our results indicate that miR-15b modulates the inflammatory response during JEV infection by negative regulation of RNF125 expression. Therefore, miR-15b targeting may constitute an interesting and promising approach to control viral-induced neuroinflammation.

High-Throughput Screening of Escherichia coli O157:H7 Pathogenic Genes via Pathway Enrichment and Operon Analysis.

BACKGROUND: About thirty thousand people globally die every day from infectious diarrhea, mostly caused by pathogenic Escherichia coli (E. coli) O157:H7. METHODS: In order to search for clinical diagnostic biomarkers and novel drug targets for infectious diarrhea, we used a bibliometric method to collect pathogenic genes of E. coli O157:H7 and performed a functional analysis of the important pathogenic genes by pathway enrichment and operon analysis. RESULTS: We found 364 pathogenic genes which may be involved in infection with E. coli O157:H7 including 50 new specific pathogenic genes. It is possible that these newly found pathogenic genes will be of great importance in the treatment of E. coli O157:H7 infected diseases and the discovery of novel diagnostic biomarkers. CONCLUSIONS: Our findings also lay a theoretical foundation for the control, diagnosis, and prognosis of pathogenic E. coli related diseases.

A Computationally Designed Serological Assay for Porcine Epidemic Diarrhea Virus.

The periodic emergence of new infectious agents and the genetic and antigenic evolution of existing agents necessitate the improvement of technology for the rapid development of diagnostic assays. The porcine epidemic diarrhea virus (PEDV) emerged in the United States in 2013, causing severe economic damage to the pork industry. The primary goal of this study was to develop methods to reduce the lead time for serological assay development. An approach involving the computational prediction of diagnostic targets, followed by a rapid synthesis of antigens, was adopted to achieve this objective. To avoid cross-reactivity with other closely related swine coronaviruses, the N protein sequences of PEDV were analyzed to identify sequences unique to PEDV. The potential antigenicity of the identified sequence was predicted computationally using the Jameson-Wolf method. A sequence with a high antigenic index was rapidly synthesized using an in vitro transcription and translation system to yield the diagnostic antigen. The computationally designed enzyme-linked immunosorbent assay (ELISA) was validated using 169 field sera, whose statuses were determined by a PEDV-specific immunofluorescence assay. Comparison of the computationally designed ELISA to a conventionally developed ELISA, using bacterially expressed N protein, and to the immunofluorescence assay showed a high degree of agreement among the three tests (mean kappa statistic, 0.842). The sensitivity and specificity, compared to the conventionally developed assay, were 90.62 and 95.18, respectively. Therefore, the described approach is useful in reducing the development time for serological assays in the face of an infectious disease outbreak.

The impact of ambient air pollution on suicide mortality: a case-crossover study in Guangzhou, China.

BACKGROUND: Preventing suicide is a global imperative. Although the effects of social and individual risk factors of suicide have been widely investigated, evidence of environmental effects of exposure to air pollution is scarce. We investigated the effects of ambient air pollution on suicide mortality in Guangzhou, China during 2003-2012. METHODS: A conditional logistic regression analysis with a time-stratified case-crossover design was performed to assess the effects of daily exposure to three standard air pollutants, including particulate matter less than 10 µm in aerodynamic diameter (PM10), sulphur dioxide (SO2) and nitrogen dioxide (NO2), on suicide mortality, after adjusting for the confounding effects of daily mean temperature, relative humidity, atmospheric pressure and sunshine duration. Further analyses were stratified by season, gender, age group, educational attainment and suicide type. RESULTS: Between 2003 and 2012, there were a total of 1 550 registered suicide deaths in Guangzhou. A significant increase in suicide risk were associated with interquartile-range increases in the concentration of air pollutant, with an odds ratio of 1.13 (95 % confidence interval (CI): 1.01, 1.27) and 1.15 (95 % CI: 1.03, 1.28) for PM10 and NO2 at lag 02, and 1.12 (95 % CI: 1.02, 1.23) for SO2 at lag 01, respectively. The suicide risks related to air pollution for males and people with high education level were higher than for females and those with low education level, respectively. Significant air pollution effects were found on violent suicide mortality and in cool season but not on non-violent suicide mortality or in warm season. CONCLUSIONS: Suicide risk was positively associated with ambient air pollution levels. This finding would provide important information for the health impact assessment of air pollution and for the development of effective strategies and interventions for the prevention of suicide.

Mutational analysis of the functional sites in porcine reproductive and respiratory syndrome virus non-structural protein 10.

Porcine reproductive and respiratory syndrome virus (PRRSV) is prevalent throughout the world and has caused major economic losses to the pig industry. Arterivirus non-structural protein 10 (nsp10) is a superfamily 1 helicase participating in multiple processes of virus replication. PRRSV nsp10, however, has not yet been well characterized. In this study, a series of nsp10 mutants were constructed and analysed for functional sites of different enzymic activities. We found that nsp10 could bind both ssDNA and dsDNA, and this binding activity could be inactivated by mutations at Cys25 and His32. These two mutations also abolished unwinding activity without affecting ATPase activity. In addition, substitution of Ala227 by Ser eliminated helicase activity, whilst substitution by Val enhanced unwinding activity. Taken together, our results showed that Cys25 and His32 in PRRSV nsp10 were critical for nucleic acid binding and unwinding, and that Ala227 played an important role in helicase activity.

Etanercept reduces neuroinflammation and lethality in mouse model of Japanese encephalitis.

BACKGROUND: Japanese encephalitis virus (JEV) is a neurotropic flavivirus that causes Japanese encephalitis (JE), which leads to high fatality rates in human. Tumor necrosis factor alpha (TNF-α) is a key factor that mediates immunopathology in the central nervous system (CNS) during JE. Etanercept is a safe anti-TNF-α drug that has been commonly used in the treatment of various human autoimmune diseases. METHODS: The effect of etanercept on JE was investigated with a JEV-infected mouse model. Four groups of mice were assigned to receive injections of phosphate-buffered saline, etanercept, JEV, or JEV plus etanercept. Inflammatory responses in mouse brains and mortality of mice were evaluated within 23 days post infection. RESULTS: The in vitro assay with mouse neuron/glia cultures showed that etanercept treatment reduced the inflammatory response induced by JEV infection. In vivo experiments further demonstrated that administration of etanercept protected mice from JEV-induced lethality. Neuronal damage, glial activation, and secretion of proinflammatory cytokines were found to be markedly decreased in JEV-infected mice that received etanercept treatment. Additionally, etanercept treatment restored the integrity of the blood-brain barrier and reduced viral load in mouse brains. CONCLUSIONS: Etanercept effectively reduces the inflammation and provides protection against acute encephalitis in a JEV-infected mouse model.

Comparison of complete genome sequences of dog rabies viruses isolated from China and Mexico reveals key amino acid changes that may be associated with virus replication and virulence.

Rabies is a global problem, but its impact and prevalence vary across different regions. In some areas, such as parts of Africa and Asia, the virus is prevalent in the domestic dog population, leading to epidemic waves and large numbers of human fatalities. In other regions, such as the Americas, the virus predominates in wildlife and bat populations, with sporadic spillover into domestic animals. In this work, we attempted to investigate whether these distinct environments led to selective pressures that result in measurable changes within the genome at the amino acid level. To this end, we collected and sequenced the full genome of two isolates from divergent environments. The first isolate (DRV-AH08) was from China, where the virus is present in the dog population and the country is experiencing a serious epidemic. The second isolate (DRV-Mexico) was taken from Mexico, where the virus is present in both wildlife and domestic dog populations, but at low levels as a consequence of an effective vaccination program. We then combined and compared these with other full genome sequences to identify distinct amino acid changes that might be associated with environment. Phylogenetic analysis identified strain DRV-AH08 as belonging to the China-I lineage, which has emerged to become the dominant lineage in the current epidemic. The Mexico strain was placed in the D11 Mexico lineage, associated with the West USA-Mexico border clade. Amino acid sequence analysis identified only 17 amino acid differences in the N, G and L proteins. These differences may be associated with virus replication and virulence-for example, the short incubation period observed in the current epidemic in China.