Network pharmacology-based exploration identified the antiviral efficacy of Quercetin isolated from mulberry leaves against enterovirus 71 via the NF-κB signaling pathway.

Introduction: Mulberry leaf (ML) is known for its antibacterial and anti-inflammatory properties, historically documented in "Shen Nong's Materia Medica". This study aimed to investigate the effects of ML on enterovirus 71 (EV71) using network pharmacology, molecular docking, and in vitro experiments. Methods: We successfully pinpointed shared targets between mulberry leaves (ML) and the EV71 virus by leveraging online databases. Our investigation delved into the interaction among these identified targets, leading to the identification of pivotal components within ML that possess potent anti-EV71 properties. The ability of these components to bind to the targets was verified by molecular docking. Moreover, bioinformatics predictions were used to identify the signaling pathways involved. Finally, the mechanism behind its anti-EV71 action was confirmed through in vitro experiments. Results: Our investigation uncovered 25 active components in ML that targeted 231 specific genes. Of these genes, 29 correlated with the targets of EV71. Quercetin, a major ingredient in ML, was associated with 25 of these genes. According to the molecular docking results, Quercetin has a high binding affinity to the targets of ML and EV71. According to the KEGG pathway analysis, the antiviral effect of Quercetin against EV71 was found to be closely related to the NF-κB signaling pathway. The results of immunofluorescence and Western blotting showed that Quercetin significantly reduced the expression levels of VP1, TNF-α, and IL-1ß in EV71-infected human rhabdomyosarcoma cells. The phosphorylation level of NF-κB p65 was reduced, and the activation of NF-κB signaling pathway was suppressed by Quercetin. Furthermore, our results showed that Quercetin downregulated the expression of JNK, ERK, and p38 and their phosphorylation levels due to EV71 infection. Conclusion: With these findings in mind, we can conclude that inhibiting the NF-κB signaling pathway is a critical mechanism through which Quercetin exerts its anti-EV71 effectiveness.

Long non-coding RNA ENST00000469812 promotes Enterovirus type 71 replication via targeting the miR-4443/NUPR1 axis in rhabdomyosarcoma cells.

Hand, foot, and mouth disease (HFMD) caused by Enterovirus type 71 (EV71) is a serious threat to children's health. However, the pathogenic mechanism of EV71 is still unclear. Long non-coding RNAs (lncRNAs), some of which bind to miRNA as competitive endogenous RNAs (ceRNA) and weaken the silencing effect on the mRNA of downstream target genes, play a key role in regulating the viral infection process. In this study, through experimental verification, we found miR-4443 to be downregulated in cells infected with EV71. Next, by predicting lncRNAs that potentially regulate miR-4443, we found that EV71 infection induced upregulation of lncRNA ENST00000469812 and then further downregulated miR-4443 expression by direct interaction. We also demonstrated that nuclear protein 1 (NUPR1) is one of the target genes of miR-4443 and is involved in the ENST00000469812/miR-4443/NUPR1 regulatory axis. Finally, the ENST00000469812/miR-4443/NUPR1 regulatory axis exhibited a positive effect on EV71 replication. Here, we lay a foundation for exploring the pathogenic mechanism of EV71 and identify potential targets for HFMD treatment.

Integrative analysis of lncRNA-miRNA-mRNA-associated competing endogenous RNA regulatory network involved in EV71 infection.

The competing endogenous RNA (ceRNA) axis has been shown to play a critical role in the pathogenesis of various viral infections. Generally, the ceRNA network involves long non-coding RNAs (lncRNAs) that act as sponges for miRNA to regulate mRNA expression. However, no information is available regarding the involvement of ceRNA networks in Enterovirus type 71 (EV71) infections. In the present study, data obtained from Gene Expression Omnibus (GEO) database was analyzed using various bioinformatics tools. EV71 infection in rhabdomyosarcoma (RD) cells was associated with differential expression of six lncRNAs, 28 miRNAs, and 349 mRNAs. Gene function enrichment analysis suggested induction of cytoplasmic vesicle process upon EV71 infection. The ceRNA networks were constructed, in which 20 hub genes were predicted by protein-protein interaction. To confirm the MALAT1/miR-194-5p/DUSP1 ceRNA regulatory axis in EV71 infection, real-time quantitative polymerase chain reaction (qRT-PCR) and luciferase reporter assay were performed. The results of the study also revealed the involvement of the MALAT1/miR-194-5p axis in apoptosis induced by EV71 infection, while no association with autophagy was observed. Thus, the present study provided novel insights into the pathogenic mechanism of EV71 infection.

Study of integrated protective immunity induced in rhesus macaques by the intradermal administration of a bivalent EV71-CA16 inactivated vaccine.

Enterovirus type 71 (EV71) and coxsackievirus A 16 (CA16) are recognized as the major pathogens responsible for human hand-foot-mouth disease. To develop a bivalent EV71-CA16 vaccine, rhesus macaques immunized with two doses of this vaccine via the intradermal route were challenged with EV71 or CA16, and their clinical symptoms, viral shedding, neutralizing antibodies, IFN-γ-specific ELISpots, and tissue viral load were examined longitudinally. Specific immunity against EV71 and CA16 was observed in the macaques, which exhibited controlled proliferation of the EV71 and CA16 viruses and upregulated expression of immune-related genes compared with the controls. Furthermore, broad protection against EV71 and CA16 challenge without immunopathological effects was observed in all the immunized macaques. These studies suggest that the bivalent EV71-CA16 inactivated vaccine was effective against wild-type EV71 or CA16 viral challenge in rhesus macaques.

Analysis of viral load and complications in children patients with severe hand-foot-mouth disease caused by enterovirus type 71 / 国际检验医学杂志

Objective To analyze the viral load and complications in children patients with severe hand-foot-mouth disease(HFMD) caused by enterovirus type 71(EV71) .Methods The clinical data in 320 children patients with severe HFMD caused by EV71 treated in this hospital from January 2013 to December 2016 were retrospectively analyzed .The viral load in children patients with severe EV 71 caused HFMD was detected by adopting the fluorescence quantitative polymerase chain reaction (Q-PCR) ,and its correlation with the compli-cations was analyzed .Results The viral load in the children patients with critical type HFMD was significant-ly higher than that in the children patient with severe type HFMD ,the difference was statistically significant (P<0 .05) .Compared with severe HFMD ,the incidence rate of nervous system damage ,respiratory failure , circulatory failure and myocardial damage in critical type HFMD were significantly increased ,the difference was statistically significant (P<0 .05) .Compared with the EV71 viral load in the children patients with asep-tic meningitis ,the EV71 viral load in the children patients with brainstem encephalitis and acute flaccid paraly-sis were increased significantly ,moreover the EV71 viral load in the children patients with acute flaccid paraly-sis was significantly higher than that in the children patients with brainstem encephalitis ,the difference was statistically significant (P<0 .05) .Conclusion The viral load in children patients with severe HFMD caused by EV71 is correlated with severity of disease condition and complications ,and the viral load detection is con-ducive to disease condition monitoring and guidance of clinical treatment .

A Novel Enterovirus 71 (EV71) Virulence Determinant: The 69th Residue of 3C Protease Modulates Pathogenicity.

Human enterovirus type 71 (EV71), the major causative agent of hand-foot-and-mouth disease, has been known to cause fatal neurological complications. Unfortunately, the reason for neurological complications that have been seen in fatal cases of the disease and the relationship between EV71 virulence and viral genetic sequences remains largely undefined. The 3C protease (3Cpro) of EV71 plays an irreplaceable role in segmenting the precursor polyprotein during viral replication, and intervening with host life activity during viral infection. In this study, for the first time, the 69th residue of 3C protease has been identified as a novel virulence determinant of EV71. The recombinant virus with single point variation, in the 69th of 3Cpro, exhibited obvious decline in replication, and virulence. We further determined the crystal structure of 3C N69D at 1.39 Ǻ resolution and found that conformation of 3C N69D demonstrated significant changes compared with a normal 3C protein, in the substrate-binding site and catalytic active site. Strikingly, one of the switch loops, essential in fixing substrates, adopts an open conformation in the 3C N69D-rupintrivir complex. Consistent with this apparent structural disruption, the catalytic activity of 3C N69D decreased sharply for host derived and viral derived substrates, detected for both in vitro and in vivo. Interestingly, in addition to EV71, Asp69 was also found in 3C proteases of other virus strains, such as CAV16, and was conserved in nearly all C type human rhinovirus. Overall, we identified a natural virulence determinant of 3C protease and revealed the mechanism of attenuated virulence is mediated by N69D substitution. Our data provides new insight into the enzymatic mechanism of a subdued 3C protease and suggests a theoretical basis for virulence determinantion of picornaviridae.

Epidemiological characteristics of enterovirus type 71 diseases / 中华流行病学杂志

Objective The objective of this study was to investigate the epidemiological characteristics of disease caused by enterovirus type 71.Methods A total of 10 158 children aged between 6 and 35 months,were recruited from 7 sites where EV71 inactivated vaccine phase 3 clinical trial was carded out.All the subjects were followed up to one year to investigate the epidemiological characteristics of the disease caused by EV71.Results The accumulate incidence density of disease caused by EV71 was 15.17/1 000 person-year.Of all the cases,hand,foot and mouth disease (HFMD),herpangina,respiratory system diseases,digestive system diseases and other diseases accounted for 82.00％,2.67％,13.33％,1.33％ and 0.67％,respectively.The difference of the incidence density between boys and girls showed no statistical significance.Majority of the patients were between 12 and 23 months of age,which accounted for 58.67％ of the total patients.The differences of incidence density between different months of age were statistically significant (x2=7.789,P=0.020).The peak incidence density of disease caused by EV71 occurred from April to June.Nine cases showed severe symptoms or signs that accounted for 6.00％ of all the cases.All severe cases were identified as HFMD,of which 7 were boys and 2 were girls.The number of severe cases in different months of age appeared to be 1,7,and 1,all occurred between April and June.The median courses of HFMD cases and non-HFMD cases were 9 and 6 days,with difference statistically significant (Z=-4.000,P＜0.001).Median of excretion cycle for HFMD and non-HFMD cases were 9 and 11 days respectively.But with no statistically significant difference between the two.Conclusion Majority of the disease that caused by EV71 appeared as HFMD.Most of them were younger children and with seasonal variation.

How to understand the efficacy measurements for enterovirus type 71 vaccine?

The choice of endpoint was most important for an efficacy vaccine trial. The objective of this paper is to gear toward answering questions about the rationality and scientificity of the primary endpoints choosing, case capturing and diagnosis strategy in our recently reported EV71 vaccine efficacy phase 3 trial. In order to obtain both high sensitivity and specificity in the case detecting, EV71-associated disease had been chosen as primary endpoint, a broad spectrum of clinical symptoms was surveyed, both the real-time RT-PCR and virus isolation were combined for the laboratory diagnosis, and serial specimens since disease onset were collected for assays. Though, the EV71 vaccine efficacy was well measured in the phase 3 trial, several potential factors could also have influences on the cases confirming. More evidence of EV71 vaccine efficacy will be demanded in post-marketing studies in the future.

Inhibition of EV71 replication in vitro by polysaccharides from Selaginella tamaritcina / 国际药学研究杂志

Objective To evaluate the inhibitory effect of polysaccharides from Selaginella tamariscina on Enterovirus 71 (EV71) replication in vitro. Methods For detecting the cytotoxicity, series of doses of polysaccharides from Selaginella tamariscina were added in RD cells, cell survival rates were evaluated by observing the cytopathic effect (CPE) and using cell counting Kit-8 (CCK8) assay, then the half toxic concentration(CC50) of the drugs were calculated. For studying the antiviral activity, the cellular model was established by infecting RD cells with EV71. Several groups were set in the experiments: normal control group, virus-infected group, positive drug treated EV71 -infected group(ribavirin 3. 2 mg/L) and series of doses of polysaccharides treated EV71 -infected groups. The CPE inhibitions were determined by using CCK8 assay and the half inhibitory concentrations of drugs(IC50) were calculated. The inhibitiory effect of polysaccharides on EV71 RNA were determined by using real-time RT-PCR methods for detecting the virus RNA levels in cell cultures. Results The CC50 of 30% and 50% alcohol precipitated polysaccharides from Selaginella tamariscina on RD cells were 396 and 142 mg/L, respectively; the IC50 calculated according to the CPE inhibitory rates were respectively 40. 8 and 26. 2 mg/L. Additionally, these two polysaccharides significantly reduced viral RNA copies in EV71-infected RD cells. Conclusion Selaginella tamariscina together with its 30% and 50% alcohol precipitated polysaccharides can be developed as potential new anti - E V 71 drugs.

Establishment and application of method to screen anti-EV71 positive plasma / 中华微生物学和免疫学杂志

Objective To evaluate the titers of EV71 neutralizing antibody in donators' plasma,and to establish a high throughput screening method to screening anti-EV71 positive plasma for the production of EV7l-specific IVIG in practice.Methods The EV71 neutralizing antibody titers in plasma samples and in commercial IVIGs (intravenous immunoglobulins) were evaluated by micro-cytopathic effect neutralization test (MCPENT),and a selecting criteria was determined for screening anti-EV71 positive plasma.Then,a high throughput neutralizing method for screening plasma was established and a comparison with MCPENT was conducted.EV71-specific IVIG was prepared from screened anti-EV71 source plasma,and its neutralizing activity was evaluated in cell model and mouse model.Results The results of MCPENT showed that the titers of EVT1 neutralizing antibody were 1 ∶ 50 or above in 20％ of the source plasma,and reached 1 ∶ 180 after being pooled,approaching to the titer of commercial IVIG.In 480 samples,the coincidence rate between the established high throughput neutralizing method and MCPENT was 88.1％.The quality of prepared EV71-specific IVIG was complied with the national standard,and its neutralizing potency was 16 times of that of IVIG,suggesting EV71-specific IVIG had a significantly improved protecting effect on experimental neonatal mice.Conclusion The screening method and the screening criteria for EV71 specific plasma were successfully established.The established high throughput neutralizing method that was operated easily could be used for plasma screening in the development of EV71-specific IVIG.The prepared EV71-specific IVIG,whose neutralizing potency was significantly improved,showed a markedly protective effect on experimental neonatal mice,suggesting it might be very important for the prevention and treatment of handfoot-and-mouth disease.

Etiological detection of severe hand-food-mouth disease and related genetic characteristics of enterovirus type 71 infection in Beijing,2010 / 中华流行病学杂志

Objective To study the etiological detection on samples from severe hand-footmouth disease (HFMD) cases and the genetic characteristics of enterovirus type 71 (EV71) isolates lrom severe patients in Beijing,2010.Methods Real-time RT-PCR was used to detect EV71 and Coxsackievirus A16 (CoxA16) and RD cells were used to separate virus strains from samples.Homogeneity of EV71 isolated strains were also analyzed. Results Four hundred and fourty-two severe cases were detected and 253 were positive,taking up 57.24％ of the total (253/442).The overall positive detection rate on EV71 was 54.55％ (138/253),with CoxA16 as 5.93％(15/253),and with other enterovirus group was 39.53％(100/253).The nucleotide homogencity of VP1 within these 12 strains was 97.2％ 100.0％,and with Beijing strains in 2007-2010,Shandong strains in 2007 and Anhui Fuyang strains in 2008 and the Guangdong strains in 2008 as 94.0％-99.9％.Conclusion Severe HFMD cases were most oftenly caused by EV71 but less caused by CoxA16 or other cnterovirus.The HFMD in 2010 in Beijing was mainly caused by EV71 subgenotype C4a with 4 transmission chains.Twclve isolated EV71 strains had high homogeneity with strains isolated from severe cases in Anhui Fuyang in 2007.

The gene characterization of VP1 and 2A of Enterovirus type 71 / 中华微生物学和免疫学杂志

Objective To detect VP1 and 2A genes of Enterovirus type 71 (EV71) isolated from clinical specimens of patients with light or heavy symptoms and analyze the homogeneity and phylogenetic tree. Methods Fifty clinical specimens of children with hand-foot-and-mouth disease ( HFMD) were dealed with, which were tested by RT-PCR assay with specific primer pairs for EV71. EV71 isolates from patients with light or heavy clinical symptoms were tested by RT-PCR assay with two specific primer pairs for VP1 and 2A genes of EV71 respectively. All of the PCR products were sequenced and compared with that of previously isolated EV71 isolates available from GenBank by homogeneity and phylogenetic tree analyses. Results The RT-PCR results indicated that 30 isolates were EV71, 13 of 30 isolates were from clinical specimens of patients with light symptoms of hand-foot and mouth, the other were from clinical specimens of patients with heavy symptoms of complications. VP1 genes and 2A genes of 10 EV71 isolated strains including 5 light strains and 5 heavy strains were sequenced and compared with that of previously isolated 5 EV71 Chinese isolates available from GenBank (fuyangEU703814.1, xi_anHM003207. 1, shandongEU753418.1, shenzhenFJ607337.1, henanGU366191. 1) by homogeneity and phylogenetic tree analyses. The homogeneity of VP1 and 2A genes of the 10 EV71 isolated strains and 5 previously isolated strains were between 94.7% -99.4% and 93.6% -99.3% respectively, with the representative isolates of A and B genotypes was between 81.0%-84. 6% and 78. 4%-82. 2% respectively. The data suggested that all of the 10 Chinese isolates belong to EV71 genotype C. There were only 87.8% -90.2% homology among these 10 strains and the representative strains of C1, C2, C3 sub-genotypes of EV71 but 96. 8% -99.6% homology among these 10 strains and the representative strains of C4 sub-genotypes of EV71, this suggested that these 10 Chinese isolates composed the C4 sub-genotype, of the C genotype, that formed a single branch in the phylogenetic tree. Conclusion EV71 of sub-genotype C4 distributed in Mainland China, and VP1 genes have close genetic relationship between isolated strains. There is no obvious difference in 2A genes between clinical specimens of patients with light or heavy symptoms by homogeneity and phylogenetic tree analyses.

Analysis on the epidemiological and genetic characteristics of enterovirus type 71 and Coxsackie A16 virus infection in Jiangsu, China, 2008 / 中华流行病学杂志

Objective To determine the epidemiological features of hand-foot-and-mouth disease (HFMD) outbreaks and the genetic characteristics of enterovirus type 71 (EV71) isolates from patients in Lianyungang, Jiangsu province in May, 2008. Methods Epidemiological, microbiological, cellular and molecular methods were performed to investigate pathogens and to describe the homogeneity of isolated strains. Results 21 cases were reported in this HFMD outbreak with the attack rate as 20.0%. 3 EV71 virus strains were isolated from 10 stool samples. The nucleotide and amino acid homogeneity of these 3 Jiangsu strain with Anhui Fuyang strains were 97.9%-100.0% and 99.7%-100.0%, respectively. These 4 Jiangsu strains were within genotype C sub-geno group C4 in phylogenetic tree. Data from the follow-up study showed that shedding of EV71 and Coxsackie A 16 virus (CA 16) in the latent period appeared in the outbreak of HFMD. Human beings could be infected by both EV71 virus and CA16 at the same time and could also carry the two viruses. We also discovered that EV71 virus could be expelled out of the human body through stool in the fast week and last for 10 weeks. Conclusion The recently identified EV71 isolates from this HFMD outbreak belonged to sub-geno group CA. Facts as: the release of viruses in the latent period, co-infection or coexisting of two viruses at the same time and super long period of expulsion of toxin exist in EV71 and CA16 did exist.

Isolation and identification of viruses from patient with hand,foot and mouth disease in Chongqing area in 2009 / 重庆医科大学学报

Objective:Toinvestigate the etiological agents of the outbreak ofhand-foot-mouth disease(HFMD)in ChongQing area from April to September in 2009.Methods:100 specimens(including cerebral spinal fluid,vesicle fluid,stool,throat swabs,anal swab) were collected from 47 patients with HFMD during the epidemic season.The specimens were inoculated into RD cells for isolation of enteroviruses(EV),The supernatant of cytopathic effect(CPE)were detected by RT-PCR with universal primers of enterovirus, genus-specific primers of EV71 and genus-specific primers of Coxsackie A16,and the amplified products were sequenced to determine the outbreak of the pathogen enteroviruses(EV),The sequencing results will be compared with international representatives BrCr strain to identify the enteroviruses(EV)by Bioedit biological software.Results:In the 100 cell cultures of clinical specimens of children HFMD, apparent Cytopathic were observed in 7.The results of RT-PCR showed that seven specimens were positive with intestinal universal primers,and three were positive results with EV71-specific primers,which were from two cases of out-patient children and one with clinical diagnosis of suspected case,while the negative results were obtained with CA16-specific primers for all the samples.The recovery of the PCR products were cloned and the sequencing identification confirmed as EV71 virus,while sequencing analysis of homology-related in the results.Conclusion:EV71 were the major etiological agents of the HFMD outbreak in Chongqing from February to April in 2009.