scholarly journals Antiviral Efficacy of Flavonoids against Enterovirus 71 Infection in Vitro and in Newborn Mice

Viruses ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 625 ◽  
Author(s):  
Wenwen Dai ◽  
Jinpeng Bi ◽  
Fang Li ◽  
Shuai Wang ◽  
Xinyu Huang ◽  
...  

Enterovirus 71 (EV71) infection is known to cause hand, foot, and mouth disease (HFMD), which is associated with neurological complications; however, there is currently no effective treatment for this infection. Flavonoids are a large group of naturally occurring compounds with multiple bioactivities, and the inhibitory effects of several flavonoids against EV71 have been studied in cell cultures; however, to date, there are no reported data on their effects in animal models. In this study, we confirmed the in vitro activities of eight flavonoids against EV71 infection, based on the inhibition of cytopathic effects. Moreover, these flavonoids were found to reduce viral genomic RNA replication and protein synthesis. We further demonstrated the protective efficacy of these flavonoids in newborn mice challenged with a lethal dose of EV71. Apigenin, luteolin, kaempferol, formononetin, and penduletin conferred survival protection of 88.89%, 91.67%, 88.89%, 75%, and 66.67%, respectively, from the lethal EV71 challenge. In addition, isorhamnetin provided the highest mice survival protection of 100% at a dose of 10 mg/kg. This study, to the best of our knowledge, is the first to evaluate the in vivo anti-EV7l activities of multiple flavonoids, and we accordingly identified flavonoids as potential leading compounds for anti-EV71 drug development.

2021 ◽  
Vol 22 (16) ◽  
pp. 8757
Author(s):  
Salima Lalani ◽  
Malihe Masomian ◽  
Chit Laa Poh

Enterovirus A71 (EV-A71) is a major neurovirulent agent capable of causing severe hand, foot and mouth disease (HFMD) associated with neurological complications and death. Currently, no FDA-approved antiviral is available for the treatment of EV-A71 infections. The flavonoid silymarin was shown to exert virucidal effects, but the binding site on the capsid was unknown. In this study, the ligand interacting site of silymarin was determined in silico and validated in vitro. Moreover, the potential of EV-A71 to develop resistance against silymarin was further evaluated. Molecular docking of silymarin with the capsid of EV-A71 indicated that silymarin binds to viral protein 1 (VP1) of EV-A71, specifically at the GH loop of VP1. The in vitro binding of silymarin with VP1 of EV-A71 was validated using recombinant VP1 through ELISA competitive binding assay. Continuous passaging of EV-A71 in the presence of silymarin resulted in the emergence of a mutant carrying a substitution of isoleucine by threonine (I97T) at position 97 of the BC loop of EV-A71. The mutation was speculated to overcome the inhibitory effects of silymarin. This study provides functional insights into the underlying mechanism of EV-A71 inhibition by silymarin, but warrants further in vivo evaluation before being developed as a potential therapeutic agent.


2005 ◽  
Vol 86 (5) ◽  
pp. 1391-1401 ◽  
Author(s):  
Minetaro Arita ◽  
Hiroyuki Shimizu ◽  
Noriyo Nagata ◽  
Yasushi Ami ◽  
Yuriko Suzaki ◽  
...  

Enterovirus 71 (EV71) is one of the major causative agents of hand, foot and mouth disease and is sometimes associated with serious neurological disorders. In this study, an attempt was made to identify molecular determinants of EV71 attenuation of neurovirulence in a monkey infection model. An infectious cDNA clone of the virulent strain of EV71 prototype BrCr was constructed; temperature-sensitive (ts) mutations of an attenuated strain of EV71 or of poliovirus (PV) Sabin vaccine strains were then introduced into the infectious clone. In vitro and in vivo phenotypes of the parental and mutant viruses were analysed in cultured cells and in cynomolgus monkeys, respectively. Mutations in 3D polymerase (3Dpol) and in the 3′ non-translated region (NTR), corresponding to ts determinants of Sabin 1, conferred distinct temperature sensitivity to EV71. An EV71 mutant [EV71(S1-3′)] carrying mutations in the 5′ NTR, 3Dpol and in the 3′ NTR showed attenuated neurovirulence, resulting in limited spread of virus in the central nervous system of monkeys. These results indicate that EV71 and PV1 share common genetic determinants of neurovirulence in monkeys, despite the distinct properties in their original pathogenesis.


2016 ◽  
Vol 91 (5) ◽  
Author(s):  
Elizabeth A. Caine ◽  
Jorge E. Osorio

ABSTRACT Hand, foot, and mouth disease (HFMD) is a reemerging illness caused by a variety of enteroviruses. The main causative agents are enterovirus 71 (EV71), coxsackievirus A16 (CVA16), and, most recently, coxsackievirus A6 (CVA6). Enterovirus infections can vary from asymptomatic infections to those with a mild fever and blisters on infected individuals' hands, feet, and throats to infections with severe neurological complications. Viral persistence for weeks postinfection (wpi) has also been documented by the demonstration of virus in children's stools. However, little is known about disease progression, viral spread, and tissue tropism of these viruses. These types of studies are limited because many recently developed mouse models mimic the severe neurological complications that occur in a small percentage of enterovirus infections. In the present study, we documented real-time EV71 infection in two different mouse strains by the use of in vivo imaging. Infection of BALB/c mice with a bioluminescent mouse-adapted EV71 construct (mEV71-NLuc) resulted in a lack of clinical signs of disease but in relatively high viral replication, as visualized by luminescence, for 2 wpi. In contrast, mEV71-NLuc infection of AG129 mice (alpha/beta and gamma interferon receptor deficient) showed rapid spread and long-term persistence of the virus in the brain. Interestingly, AG129 mice that survived infection maintained luminescence in the brain for up to 8 wpi. The results we present here will allow future studies on EV71 antiviral drug susceptibility, vaccine efficacy, transmissibility, and pathogenesis. IMPORTANCE We report here that a stable full-length enterovirus 71 (EV71) reporter construct was used to visualize real-time viral spread in AG129 and BALB/c mice. To our knowledge, this is the first report of in vivo imaging of infection with any member of the Picornaviridae family. The nanoluciferase (NLuc) gene, one of the smallest luciferase genes currently available, was shown to be stable in the EV71 genome for eight passages on rhabdomyosarcoma cells. Real-time visualization of EV71 infection in mice identified areas of tropism that would have been missed by traditional methods, including full characterization of EV71 replication in BALB/c mice. Additionally, the bioluminescent construct allowed for increased speed and sensitivity of cell culture assays and will allow future studies involving various degrees of enterovirus infection in mice, not just severe infections. Our data suggest that interferon plays an important role in controlling EV71 infection in the central nervous system of mice.


2019 ◽  
Vol 5 (3) ◽  
pp. eaau4255 ◽  
Author(s):  
Charles Good ◽  
Alexandra I. Wells ◽  
Carolyn B. Coyne

Recent worldwide outbreaks of enterovirus 71 (EV71) have caused major epidemics of hand, foot, and mouth disease with severe neurological complications, including acute flaccid paralysis. EV71 is transmitted by the enteral route, but little is known about the mechanisms it uses to cross the human gastrointestinal tract. Using primary human intestinal epithelial monolayers, we show that EV71 infects the epithelium from the apical surface, where it preferentially infects goblet cells. We found that EV71 infection did not alter epithelial barrier function but did reduce the expression of goblet cell–derived mucins, suggesting that it alters goblet cell function. We also show that the intestinal epithelium responds to EV71 infection through the selective induction of type III interferons (IFNs), which restrict EV71 replication. Collectively, these findings define the early events associated with EV71 infections of the human intestinal epithelium and show that host IFN signaling controls replication in an IFN-specific manner.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Xinran Zou ◽  
Jing Wu ◽  
Jiaqi Gu ◽  
Li Shen ◽  
Lingxiang Mao

Abstract Background Enterovirus 71 (EV-A71) is a highly infectious pathogen associated with hand, foot and mouth disease, herpangina, and various neurological complications, so it is important for the early detection and treatment of EV-A71. An aptamer is a nucleotide sequence that screened in vitro by the technology named systematic evolution of ligands by exponential enrichment technology (SELEX). Similar to antibodies, aptamers can bind to the targets with high specificity and affinity. Besides, emerging aptamers have many advantages comparing with antibodies, such as ease of synthesis and modification, having a wide variety of target materials, low manufacturing cost and easy flexibility in amending. Therefore, aptamers are promising in virus detection and anti-virus therapy. Methods Aptamers were selected by SELEX. Specificity, affinity and second structure were used to characterize the selected aptamers. Chemiluminescence was adopted to build an aptamer-based detection method for EV-A71. Cytopathogenic effects trial, the level of intracellular EV-A71 RNA and protein expression were used to evaluate the antiviral effect of the selected aptamers. Results Three DNA aptamers with high specificity and affinity for EV-A71structual protein VP1 were screened out. A rapid chemiluminutesescence aptamer biosensor for EV-A71 detection was designed out. The selected aptamers could inhibit the RNA replication and protein expression of EV-A71 in RD cells and ameliorate the cytopathogenic effects. Conclusions The aptamers against EV-A71 have the potentiality to be applied as attractive candidates used for EV-A71 detection and treatment in the future.


2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Wenying Gao ◽  
Min Hou ◽  
Xin Liu ◽  
Zhaolong Li ◽  
Yongjun Yang ◽  
...  

Enterovirus 71 (EV71) is the causative pathogen of hand, foot, and mouth disease (HFMD). However, no effective antiviral therapy is currently available. Some viruses could escape the host’s innate immunity by upregulating suppressor of cytokine signaling (SOCS) proteins. Until now, whether EV71 evades the host immune system by regulating the expression of SOCS proteins remains unknown. In this study, we found that EV71 infection promoted SOCS expression at both mRNA and protein levels in vitro and in vivo. Consistently, the infectivity of EV71 was decreased significantly in the SOCS3 or SOCS1 knockdown cells, suggesting that SOCS1 and especially SOCS3 are crucial for EV71 infection. Further investigation showed that SOCS3 promoted virus infection by inhibiting interferon-induced STAT3 phosphorylation. SOCS1 and SOCS3 mRNA expressions were independent on virus-induced type I interferon expression but were blocked by the inhibitor of NF-κB. Therefore, EV71 infection stimulates the expression of SOCS proteins in an interferon-independent way and negatively regulates the JAK/STAT signaling pathway, thus escaping host immunity. All these results may add new information to the mechanism of EV71 in fighting against type I interferon responses.


2018 ◽  
Author(s):  
Charles Good ◽  
Alexandra I. Wells ◽  
Carolyn B. Coyne

AbstractRecent worldwide outbreaks of enterovirus (EV71) have caused major epidemics of hand, foot, and mouth disease (HFMD) with severe neurological complications, including acute flaccid paralysis. EV71 is transmitted by the enteral route, but very little is known about the mechanisms it utilizes to cross the human gastrointestinal (GI) tract. Using primary human intestinal epithelial monolayers, we show that EV71 infects the GI epithelium from the apical surface, where it preferentially infects goblet cells. Unlike echovirus 11 (E11), an enterovirus that infects enterocytes, EV71 infection did not alter epithelial barrier function, but did reduce the expression of a goblet cell-derived mucin, suggesting it alters goblet cell function. We also show that the intestinal epithelium responds to EV71 infection through the selective induction of type III IFNs, which potently restrict EV71 replication. Collectively, these findings define the early events associated with EV71 infections of the human intestinal epithelium and show that host IFN signaling controls replication in an IFN-specific manner.


2019 ◽  
Vol 9 (24) ◽  
pp. 5420 ◽  
Author(s):  
Fabrizio Francomano ◽  
Anna Caruso ◽  
Alexia Barbarossa ◽  
Alessia Fazio ◽  
Chiara La Torre ◽  
...  

β-Caryophyllene (BCP), a natural bicyclic sesquiterpene, is a selective phytocannabinoid agonist of type 2 receptors (CB2-R). It isn’t psychogenic due to the absence of an affinity to cannabinoid receptor type 1 (CB1). Among the various biological activities, BCP exerts anti-inflammatory action via inhibiting the main inflammatory mediators, such as inducible nitric oxide synthase (iNOS), Interleukin 1 beta (IL-1β), Interleukin-6 (IL-6), tumor necrosis factor-alfa (TNF-α), nuclear factor kapp a-light-chain-enhancer of activated B cells (NF-κB), cyclooxygenase 1 (COX-1), cyclooxygenase 2 (COX-2). Peroxisome proliferator-activated receptors alpha (PPAR-α) effects are also mediated by the activation of PPAR-α and PPAR-γ receptors. In detail, many studies, in vitro and in vivo, suggest that the treatment with β-caryophyllene improves the phenotype of animals used to model various inflammatory pathologies, such as nervous system diseases (Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis, stroke), atherosclerosis, and tumours (colon, breast, pancreas, lymphoma, melanoma and glioma cancer). Furthermore, pre-clinical data have highlighted that BCP is potentially useful in Streptococcus infections, osteoporosis, steatohepatitis, and exerts anticonvulsant, analgesic, myorelaxing, sedative, and antidepressive effects. BCP is non-toxic in rodents, with a Lethal dose, 50% (LD50) greater than 5000 mg/kg. Nevertheless, it inhibits various cytochrome P450 isoforms (above all, CYP3A4), which metabolise xenobiotics, leading to adverse effects, due to drug levels over therapeutic window. All the reported data have highlighted that both pharmacological and toxicological aspects need to be further investigated with clinical trials.


2011 ◽  
Vol 18 (5) ◽  
pp. 825-834 ◽  
Author(s):  
Shimin Zhang ◽  
Shaw-Huey Feng ◽  
Bingjie Li ◽  
Hyung-Yong Kim ◽  
Joe Rodriguez ◽  
...  

ABSTRACTOur laboratory has developed more than a hundred mouse monoclonal antibodies (MAbs) againstBurkholderia pseudomalleiandBurkholderia mallei. These antibodies have been categorized into different groups based on their specificities and the biochemical natures of their target antigens. The current study first examined the bactericidal activities of a number of these MAbs by anin vitroopsonic assay. Then, thein vivoprotective efficacy of selected MAbs was evaluated using BALB/c mice challenged intranasally with a lethal dose of the bacteria. The opsonic assay using dimethyl sulfoxide-treated human HL-60 cells as phagocytes revealed that 19 out of 47 tested MAbs (40%) have prominent bactericidal activities againstB. pseudomalleiand/orB. mallei. Interestingly, all MAbs with strong opsonic activities are those with specificity against either the capsular polysaccharides (PS) or the lipopolysaccharides (LPS) of the bacteria. On the other hand, none of the MAbs reacting to bacterial proteins or glycoproteins showed prominent bactericidal activity. Further study revealed that the antigenic epitopes on either the capsular PS or LPS molecules were readily available for binding in intact bacteria, while the epitopes on proteins/glycoproteins were less accessible to the MAbs. Ourin vivostudy showed that four MAbs reactive to either the capsular PS or LPS were highly effective in protecting mice against lethal bacterial challenge. The result is compatible with that of ourin vitrostudy. The MAbs with the highest protective efficacy are those reactive to either the capsular PS or LPS of theBurkholderiabacteria.


Author(s):  
Nurgozhin T. ◽  
Sergazy S. H. ◽  
Adilgozhina G. ◽  
Gulyayev A. ◽  
Shulgau Z. ◽  
...  

Objective:This study investigates the hepatoprotective effect and the antioxidant role of polyphenol concentrate in the experimental model of carbon tetrachloride (CCl4) induced toxicity. Methods: Antioxidant activity of Cabernet Sauvignon grape polyphenol were evaluated by radical scavenging of 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), 2,2’-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS.+). In addition, the effects of polyphenol concentrate on the survival of Wistar rats in the toxicity model, was also investigated. The polyphenol concentrate was administered for 5 five days prior to injection of carbon tetrachloride in a sub-lethal dose of 300 mg/kg of animal body weight in order to perform histological examinations of the liver and kidney, and detect the levels of AST, ALT and bilirubin. Results: Administration of polyphenol concentrate increased animal survival in the experimental model. Moreover, the intragastric administration of polyphenol concentrate prior to the initiation of the experimental model of toxicity, which was caused by a sub-lethal CCl4 dose, reduced morphological injuries in the liver and kidney, decreased the AST and ALT levels of the blood serum. Discussion and conclusion: Our data demonstrate that polyphenol concentrate possesses an antioxidant potential both in vitro and in vivo by reducing antioxidant stress that was caused by CCl4 administration into rats.


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