Global emergence of Enterovirus 71: a systematic review

NLRP3-dependent pyroptosis exacerbates coxsackievirus A16 and coxsackievirus A10-induced inflammatory response and viral replication in SH-SY5Y cells

Coxsackievirus A16 (CV-A16) and coxsackievirus A10 (CV-A10), more commonly etiological agents of hand, foot and mouth disease (HFMD), are capable of causing severe neurological syndromes with high fatalities, but their neuropathogenesis has rarely been studied. Mounting evidence indicated that pyroptosis is an inflammatory form of cell death that might be widely involved in the pathogenic mechanisms of neurotropic viruses. Our study was designed to examine the effects of NLRP3-mediated pyroptosis in CV-A16- and CV-A10-induced inflammatory neuropathologic formation. In this work, it was showed that SH-SY5Y cells were susceptible to CV-A16 and CV-A10, and meanwhile their infections could result in a decreasing cell viability and an increasing LDH release as well as Caspase1 activation. Moreover, CV-A16 and CV-A10 infections triggered NLRP3-mediated pyroptosis and promoted the release of inflammatory cytokines. Additionally, activated NLRP3 accelerated the pyroptosis formation and aggravated the inflammatory response, but inhibited NLRP3 had a dampening effect on the above situation. Finally, it was further revealed that NLRP3 agonist enhanced the viral replication, but NLRP3 inhibitor suppressed the viral replication, suggesting that NLRP3-driven pyroptosis might support CV-A16 and CV-A10 production in SH-SY5Y cells. Together, our findings demonstrated a mechanism by which CV-A16 and CV-A10 induce inflammatory responses by evoking NLRP3 inflammasome-regulated pyroptosis, which in turn further stimulated the viral replication, providing novel insights into the pathogenesis of CV-A16 and CV-A10 infections.

Scorpion Venom Antimicrobial Peptide Derivative BmKn2-T5 Inhibits Enterovirus 71 in the Early Stages of the Viral Life Cycle In Vitro

Enterovirus 71 (EV71), a typical representative of unenveloped RNA viruses, is the main pathogenic factor responsible for hand, foot, and mouth disease (HFMD) in infants. This disease seriously threatens the health and lives of humans worldwide, especially in the Asia-Pacific region. Numerous animal antimicrobial peptides have been found with protective functions against viruses, bacteria, fungi, parasites, and other pathogens, but there are few studies on the use of scorpion-derived antimicrobial peptides against unenveloped viruses. Here, we investigated the antiviral activities of scorpion venom antimicrobial peptide BmKn2 and five derivatives, finding that BmKn2 and its derivative BmKn2-T5 exhibit a significant inhibitory effect on EV71. Although both peptides exhibit characteristics typical of amphiphilic α-helices in terms of their secondary structure, BmKn2-T5 displayed lower cellular cytotoxicity than BmKn2. BmKn2-T5 was further found to inhibit EV71 in a dose-dependent manner in vitro. Moreover, time-of-drug-addition experiments showed that BmKn2-T5 mainly restricts EV71, but not its virion or replication, at the early stages of the viral cycle. Interestingly, BmKn2-T5 was also found to suppress the replication of the enveloped viruses DENV, ZIKV, and HSV-1 in the early stages of the viral cycle, which suggests they may share a common early infection step with EV71. Together, the results of our study identified that the scorpion-derived antimicrobial peptide BmKn2-T5 showed valuable antiviral properties against EV71 in vitro, but also against other enveloped viruses, making it a potential new candidate therapeutic molecule.

A review on the pharmacology, pharmacokinetics and toxicity of sophocarpine

Sophocarpine is a natural compound that belongs to the quinolizidine alkaloid family, and has a long history of use and widespread distribution in traditional Chinese herbal medicines such as Sophora alopecuroides L., Sophora flavescens Ait., and Sophora subprostrata. This article aims to summarize the pharmacology, pharmacokinetics, and toxicity of sophocarpine, evaluate its potential pharmacological effects in various diseases, and propose the necessity for further research and evaluation to promote its clinical application. A large number of studies have shown that it has anti-inflammatory, analgesic, antiviral, antiparasitic, anticancer, endocrine regulatory, and organ-protective effects as it modulates various signaling pathways, such as the NF-κB, MAPK, PI3K/AKT, and AMPK pathways. The distribution of sophocarpine in the body conforms to a two-compartment model, and sophocarpine can be detected in various tissues with a relatively short half-life. Although the pharmacological effects of sophocarpine have been confirmed, toxicity and safety assessments and reports on molecular mechanisms of its pharmacological actions have been limited. Given its significant pharmacological effects and potential clinical value, further research and evaluation are needed to promote the clinical application of sophocarpine.

Caboxamycin Inhibits Heart Inflammation in a Coxsackievirus B3-Induced Myocarditis Mouse Model

Coxsackievirus B3 (CVB3) is a positive single-strand RNA genome virus which belongs to the enterovirus genus in the picornavirus family, like poliovirus. It is one of the most prevalent pathogens that cause myocarditis and pancreatitis in humans. However, a suitable therapeutic medication and vaccination have yet to be discovered. Caboxamycin, a benzoxazole antibiotic isolated from the culture broth of the marine strain Streptomyces sp., SC0774, showed an antiviral effect in CVB3-infected HeLa cells and a CVB3-induced myocarditis mouse model. Caboxamycin substantially decreased CVB3 VP1 production and cleavage of translation factor eIF4G1 from CVB3 infection. Virus-positive and -negative strand RNA was dramatically reduced by caboxamycin treatment. In addition, the cleavage of the pro-apoptotic molecules BAD, BAX, and caspase3 was significantly inhibited by caboxamycin treatment. In animal experiments, the survival rate of mice was improved following caboxamycin treatment. Moreover, caboxamycin treatment significantly decreased myocardial damage and inflammatory cell infiltration. Our study showed that caboxamycin dramatically suppressed cardiac inflammation and mouse death. This result suggests that caboxamycin may be suitable as a potential antiviral drug for CVB3.

Design, synthesis, and molecular modeling studies of novel 2-quinolone-1,2,3-triazole-α-aminophosphonates hybrids as dual antiviral and antibacterial agents

With the aim to identify new antiviral agents with antibacterial properties, a series of 2-quinolone-1,2,3-triazole derivatives bearing α-aminophosphonates was synthesized and characterized by 1H NMR, 13C NMR, 31P NMR, single crystal XRD and HRMS analyses. These compounds were examined against five RNA viruses (YFV, ZIKV, CHIKV, EV71 and HRV) from three distinct families (Picornaviridae, Togaviridae and Flaviviridae) and four bacterial strains (S. aureus, E. feacalis, E. coli and P. aeruginosa). The α-aminophosphonates 4f, 4i, 4j, 4k, 4p and 4q recorded low IC50 values of 6.8-10.91 μM, along with elevated selectivity indices ranging from 2 to more than 3, particularly against YFV, CHIKV and HRV-B14. Besides, the synthesized compounds were generally more sensitive toward Gram-positive bacteria, with the majority of them displaying significant potency against E. feacalis. Specifically, an excellent anti-enterococcus activity was obtained by compound 4q with MIC and MBC values of 0.03 μmol/mL, which were 8.7 and 10 times greater than those of the reference drugs ampicillin and rifampicin, respectively. Also, compounds 4f, 4p and 4q showed potent anti-staphylococcal activity with MIC values varying between 0.11 and 0.13 μmol/mL, compared to 0.27 μmol/mL for ampicillin. The results from DFT and molecular docking simulations were in agreement with the biological assays, proving the binding capability of hybrids 4f, 4i, 4j, 4k, 4p and 4q with viral and bacterial target enzymes through hydrogen bonds and other non-covalent interactions. The in silico ADME/Tox prediction revealed that these molecules possess moderate to good drug-likeness and pharmacokinetic properties, with a minimal chance of causing liver toxicity or carcinogenic effects.

Wastewater-based surveillance as a tool for public health action: SARS-CoV-2 and beyond

Wastewater-based surveillance (WBS) has undergone dramatic advancement in the context of the coronavirus disease 2019 (COVID-19) pandemic. The power and potential of this platform technology were rapidly realized when it became evident that not only did WBS-measured SARS-CoV-2 RNA correlate strongly with COVID-19 clinical disease within monitored populations but also, in fact, it functioned as a leading indicator. Teams from across the globe rapidly innovated novel approaches by which wastewater could be collected from diverse sewersheds ranging from wastewater treatment plants (enabling community-level surveillance) to more granular locations including individual neighborhoods and high-risk buildings such as long-term care facilities (LTCF). Efficient processes enabled SARS-CoV-2 RNA extraction and concentration from the highly dilute wastewater matrix. Molecular and genomic tools to identify, quantify, and characterize SARS-CoV-2 and its various variants were adapted from clinical programs and applied to these mixed environmental systems. Novel data-sharing tools allowed this information to be mobilized and made immediately available to public health and government decision-makers and even the public, enabling evidence-informed decision-making based on local disease dynamics. WBS has since been recognized as a tool of transformative potential, providing near-real-time cost-effective, objective, comprehensive, and inclusive data on the changing prevalence of measured analytes across space and time in populations. However, as a consequence of rapid innovation from hundreds of teams simultaneously, tremendous heterogeneity currently exists in the SARS-CoV-2 WBS literature. This manuscript provides a state-of-the-art review of WBS as established with SARS-CoV-2 and details the current work underway expanding its scope to other infectious disease targets.

Post-infectious Transverse Myelitis Secondary to Hand, Foot, and Mouth Disease in a Pregnant Daycare Worker

Transverse myelitis (TM) is a rare inflammatory disorder of the spinal cord that infections, vaccines, and autoimmune processes can cause or may have no discernible cause. About half of the cases are caused by an infection, usually a viral respiratory infection, flu-like illness, or sometimes a gastrointestinal infection. Although coxsackieviruses and enteroviruses are known to cause TM, it is more commonly associated with respiratory symptoms or systemic signs than a rash. In this case, we present a pregnant daycare worker who had a case of longitudinally extensive TM after an episode of hand, foot, and mouth disease (HFMD), which only showed the typical rash without fever or systemic signs.

Environmental surveillance reveals co-circulation of distinctive lineages of enteroviruses in southwest China's border cities, 2020-2022

AIMS

Enteroviruses are significant human pathogens associated with a range of mild to severe diseases. This study aims to understand the diversity and genetic characterization of enteroviruses circulated in southwest China's border cities by using environmental surveillance.

METHODS AND RESULTS

A total of 96 sewage samples were collected in three border cities and a port located in Yunnan Province, China from July 2020 to June 2022. After cell culture and VP1 sequencing, a total of 590 enterovirus isolates were identified, belonging to 21 types. All PV strains were Sabin-like with ≤6 nucleotide mutations in the VP1 coding region. Echovirus 6, echovirus 21 (a rare serotype in previous studies), and coxsackievirus B5 were the predominant serotypes, which accounted for 21.19%, 18.31%, and 13.39% of the total isolates, respectively. The prevalence of the common serotypes varied across different border cities and periods. Phylogenetic analysis revealed the presence of multiple evolutionary lineages for E21, E6, and E30, some of which formed distinct branches.

CONCLUSIONS

High diversity of enteroviruses and distinct lineages of predominant serotypes circulated in southwest China's border cities.

Cordycepin Inhibits Enterovirus A71 Replication and Protects Host Cell from Virus-Induced Cytotoxicity through Adenosine Action Pathway

Enterovirus A71 (EV-A71) infection typically causes mild illnesses, such as hand-foot-and-mouth disease (HFMD), but occasionally leads to severe or fatal neurological complications in infants and young children. Currently, there is no specific antiviral treatment available for EV-A71 infection. Thus, the development of an effective anti-EV-A71 drug is required urgently. Cordycepin, a major bioactive compound found in Cordyceps fungus, has been reported to possess antiviral activity. However, its specific activity against EV-A71 is unknown. In this study, the potency and role of cordycepin treatment on EV-A71 infection were investigated. Results demonstrated that cordycepin treatment significantly reduced the viral load and viral ribonucleic acid (RNA) level in EV-A71-infected Vero cells. In addition, EV-A71-mediated cytotoxicity was significantly inhibited in the presence of cordycepin in a dose-dependent manner. The protective effect can also be extended to Caco-2 intestinal cells, as evidenced by the higher median tissue culture infectious dose (TCID50) values in the cordycepin-treated groups. Furthermore, cordycepin inhibited EV-A71 replication by acting on the adenosine pathway at the post-infection stage. Taken together, our findings reveal that cordycepin could be a potential antiviral candidate for the treatment of EV-A71 infection.

Recent Advances in Enterovirus A71 Infection and Antiviral Agents

Enterovirus A71 (EV-A71) is one of the major causative agents of hand, foot, and mouth disease (HFMD) that majorly affects children. Most of the time, HFMD is a mild disease but can progress to severe complications, such as meningitis, brain stem encephalitis, acute flaccid paralysis, and even death. HFMD caused by EV-A71 has emerged as an acutely infectious disease of highly pathogenic potential in the Asia-Pacific region. In this review, we introduced the properties and life cycle of EV-A71, and the pathogenesis and the pathophysiology of EV-A71 infection, including tissue tropism and host range of virus infection, the diseases caused by the virus, as well as the genes and host cell immune mechanisms of major diseases caused by enterovirus 71 (EV-A71) infection, such as encephalitis and neurologic pulmonary edema. At the same time, clinicopathologic characteristics of EV-A71 infection were introduced. There is currently no specific medication for EV-A71 infection, highlighting the urgency and significance of developing suitable anti-EV-A71 agents. This overview also summarizes the targets of existing anti-EV-A71 agents, including virus entry, translation, polyprotein processing, replication, assembly and release; interferons; interleukins; the mitogen-activated protein kinase, phosphatidylinositol 3-kinase, and protein kinase B signaling pathways; the oxidative stress pathway; the ubiquitin-proteasome system; and so on. Furthermore, it overviews the effects of natural products, monoclonal antibodies, and RNA interference against EV-A71. It also discusses issues limiting the research of antiviral drugs. This review is a systematic and comprehensive summary of the mechanism and pathological characteristics of EV-A71 infection, the latest progress of existing anti-EV-A71 agents. It would provide better understanding and guidance for the research and application of EV-A71 infection and antiviral inhibitors.

High mobility group box 1 knockdown inhibits EV71 replication and attenuates cell pyroptosis through TLR4/NF-κB/NLRP3 axis

Enterovirus 71 (EV71) is a major causative agent of hand, foot, and mouth disease (HFMD) in children. Nowadays, there are still no effective antiviral drugs for EV71 infection. High mobility group box 1 (HMGB1) is reported to be highly expressed in HFMD patients. However, the role and underlying mechanism of HMGB1 in EV71-associated HFMD are still unclear. HMGB1 expression was detected using RT-qPCR and western blot assays. Loss- and gain-function experiments were performed to evaluate the effects of HMGB1 on EV71-infected cells. The virus titer was examined by TCID50. CCK-8 and flow cytometry assays were applied to detect the cell viability and cell cycle. Oxidative stress was determined by relative commercial kits. HMGB1 level was elevated in the serum of EV71-infected patients with HFMD and EV71-induced RD cells. EV71 infection induced the transfer of HMGB1 from the nucleus into the cytoplasm. HMGB1 knockdown inhibited virus replication, viral protein (VP1) expression and promoted antiviral factor expression. In addition, the inhibition of HMGB1 improved cell viability, protected against S phase arrest, and inhibited EV71-induced cell injury and oxidative stress, whereas HMGB1 overexpression showed the opposite effects. In terms of mechanism, HMGB1 overexpression activated the TLR4/NF-κB/NLRP3 signaling pathway and promoted cell pyroptosis. The inhibition of TLR4 and NF-κB reversed the effects of HMGB1 overexpression on virus replication, oxidative stress, and pyroptosis. In conclusion, HMGB1 knockdown inhibits EV71 replication and attenuates pyroptosis through TLR4/NF-κB/NLRP3 axis.

The Repurposing of Cellular Proteins during Enterovirus A71 Infection

Viruses pose a great threat to people's lives. Enterovirus A71 (EV-A71) infects children and infants all over the world with no FDA-approved treatment to date. Understanding the basic mechanisms of viral processes aids in selecting more efficient drug targets and designing more effective antivirals to thwart this virus. The 5'-untranslated region (5'-UTR) of the viral RNA genome is composed of a cloverleaf structure and an internal ribosome entry site (IRES). Cellular proteins that bind to the cloverleaf structure regulate viral RNA synthesis, while those that bind to the IRES also known as IRES trans-acting factors (ITAFs) regulate viral translation. In this review, we survey the cellular proteins currently known to bind the 5'-UTR and influence viral gene expression with emphasis on comparing proteins' functions and localizations pre- and post-(EV-A71) infection. A comprehensive understanding of how the host cell's machinery is hijacked and reprogrammed by the virus to facilitate its replication is crucial for developing effective antivirals.

Human super antibody to viral RNA-dependent RNA polymerase produced by a modified Sortase self-cleave-bacteria surface display system

BACKGROUND

RNA-dependent RNA polymerase (RdRp) is a good target of anti-RNA virus agents; not only it is pivotal for the RNA virus replication cycle and highly conserved among RNA viruses across different families, but also lacks human homolog. Recently, human single-chain antibody (HuscFv) that bound to thumb domain of hepatitis C virus (HCV) RNA-dependent RNA polymerase (functionalized NS5B protein) was produced and engineered into cell-penetrating antibody (super antibody) in the form of cell-penetrating peptide (penetratin, PEN)-linked HuscFv (PEN-HuscFv34). The super antibody was produced and purified from inclusion body (IB) of a pen-huscfv34-vector-transformed Escherichia coli. The super antibody inhibited replication of alpha- and beta- coronaviruses, flaviviruses, and picornaviruses that were tested (broadly effective); thus, it has high potential for developing further towards a pan-anti-RNA virus agent. However, production, purification, and refolding of the super antibody molecules from the bacterial IB are laborious and hurdles to large-scale production. Therefore, in this study, Sortase-self-cleave method and bacteria surface display system were combined and modified for the super antibody production.

METHODS AND RESULTS

BL21 (DE3) ΔA E. coli, a strain lacking predominant outer membrane protein (OmpA) and ion and OmpT proteases, that displayed a membrane-anchored fusion protein, i.e., chimeric lipoprotein (Lpp')-OmpA', SUMO, Sortase protease, Sortase cleavage site (LPET↓G) and PEN-HuscFv34-6× His was generated. The soluble PEN-HuscFv34-6× His with glycine at the N-terminus could be released from the E. coli surface, simply by incubating the bacterial cells in a Sortase-cleavage buffer. After centrifugation, the G-PEN-HuscFv34-6× His could be purified from the supernatant. The purified G-PEN-HuscFv34-6× retained original cell-penetrating ability (being super antibody) and the broadly effective anti-RNA virus activity of the original IB-derived-PEN-HuscFv34.

CONCLUSION

The functionalized super antibody to RNA virus RdRp was successfully produced by using combined Sortase self-cleave and bacterial surface display systems with modification. The display system is suitable for downstream processing in a large-scale production of the super antibody. It is applicable also for production of other recombinant proteins in soluble free-folding form.

Kaempferol: A Review of Current Evidence of Its Antiviral Potential

Kaempferol and its derivatives are flavonoids found in various plants, and a considerable number of these have been used in various medical applications worldwide. Kaempferol and its compounds have well-known antioxidant, anti-inflammatory and antimicrobial properties among other health benefits. However, the antiviral properties of kaempferol are notable, and there is a significant number of experimental studies on this topic. Kaempferol compounds were effective against DNA viruses such as hepatitis B virus, viruses of the alphaherpesvirinae family, African swine fever virus, and pseudorabies virus; they were also effective against RNA viruses, namely feline SARS coronavirus, dengue fever virus, Japanese encephalitis virus, influenza virus, enterovirus 71, poliovirus, respiratory syncytial virus, human immunodeficiency virus, calicivirus, and chikungunya virus. On the other hand, no effectiveness against murine norovirus and hepatitis A virus could be determined. The antiviral action mechanisms of kaempferol compounds are various, such as the inhibition of viral polymerases and of viral attachment and entry into host cells. Future research should be focused on further elucidating the antiviral properties of kaempferol compounds from different plants and assessing their potential use to complement the action of antiviral drugs.

The neuropathological mechanism of EV-A71 infection attributes to inflammatory pryoptosis and viral replication via activating the hsa_circ_0045431/ hsa_miR_584/NLRP3 regulatory axis

Neuropathological damage has been considered to be the main cause of death from EV-A71 infection, but the underlying mechanism has not been elucidated. Pyroptosis, a new form of inflammatory programmed cell death, has been verified to be involved in the pathogenesis of various viruses. circRNAs are a novel type of endogenous noncoding RNA gaining research interest in recent years, especially their special roles in the process of virus infection. Thus, in this study, we combined EV-A71, pyroptosis and circRNA to find a breakthrough in the pathogenesis of EV-A71 infection. Firstly, whether EV-A71 infection leaded to pyroptosis formation was examined by a series detection of cell death, cell viability, LDH release, caspase 1 activity, the expression levels of pyroptosis-related molecules and the concentrations of IL-1β and IL-18. Secondly, high-throughput sequencing of circRNAs was carried out to excavate the circRNA-miRNA-mRNA regulatory axis which might be associated with pyroptosis formation. Finally, the gain- and loss-of-functional experiments were further conducted to identify their functions. Our results showed that EV-A71 infection caused pyroptosis formation in SH-SY5Y cells. The circRNA sequencing analyzed the differentially expressed circRNAs and their possible functions. It was found that the hsa_circ_0045431/hsa_miR_584/NLRP3 regulatory axis might be involved in pyroptosis formation during EV-A71 infection. Then, hsa_circ_0045431 sponged hsa_miR_584 and hsa_miR_584 directly targeted NLRP3 were validated by IF, dual-luciferase, qRT-PCR and WB assays. Functional experiments were performed to further uncover that the up-regulation of hsa_circ_0045431 and NLRP3 promoted the inflammatory pyroptosis and viral replication, while the up-regulation of hsa_miR_584 suppressed the inflammatory pyroptosis and viral replication, and vice versa. Collectively, our study demystified that EV-A71 infection induced pyroptosis formation by activating hsa_circ_0045431/hsa_miR_584/NLRP3 regulatory axis, which could further effect viral replication. These findings provided novel insights into the pathogenesis of EV-A71 infection, and meanwhile revealed that the hsa_circ_0045431/ hsa_miR_584/NLRP3 regulatory axis can serve as a potential biological therapeutic target for EV-A71 infection.

Metformin inhibits EV71‑induced pyroptosis by upregulating DEP domain‑containing mTOR‑interacting protein

Enterovirus 71 (EV71) infection is one of the main causes of severe hand, foot and mouth disease (HFMD), which is usually accompanied by a marked inflammatory response. The excessive inflammatory response has been implicated to serve an important role in EV71-caused HFMD. Pyroptosis is a type of inflammatory programmed cell death. Therefore, a novel treatment strategy against EV71 infection could aim to alleviate the inflammatory response through inhibition of EV71-induced pyroptosis. The present study revealed that metformin had this therapeutic potential. A cell model of EV71 infection was established, cell viability was measured by CCK8 assay, cell damage was measured by LDH release kit, and the dead and dying cells were excluded by propidium iodide staining. The intracellular levels of DEP domain-containing mTOR interacting protein (DEPTOR) and pyroptosis-associated molecules were measured by western blot analysis, the NLRP3 expression was assessed by immunofluorescence labeling, and virus titers in cell culture supernatants were determined by a cell culture infectious dose 50 assay. The results demonstrated that EV71 infection could induce pyroptosis in a time- and dose-dependent manner, and metformin could inhibit EV71-induced pyroptosis. The mechanism of metformin inhibiting EV71-induced pyroptosis was explored next. Subsequent experiments indicated that metformin could increase the levels of DEPTOR, which were decreased by EV71. Finally, overexpression of DEPTOR in cells could reduce EV71-induced pyroptosis. Overall, the present study demonstrated that metformin could exert a novel pharmacodynamic anti-pyroptosis effect in the treatment of EV71 infection by upregulating DEPTOR expression.

Enterovirus 71 enters human brain microvascular endothelial cells through an ARF6-mediated endocytic pathway

Infection of the central nervous system caused by enterovirus 71 (EV71) remains the main cause of death in hand-foot-and-mouth disease. However, the mechanism responsible for how EV71 breaks through the blood-brain barrier to infect brain cells has yet to be elucidated. By performing a high-throughput small interfering RNA (siRNA) screening and validation, we found that the infection of human brain microvascular endothelial cells (HBMECs) by EV71 was independent of the endocytosis pathways mediated by caveolin, clathrin, and macropinocytosis but dependent on ADP-ribosylation factor 6 (ARF6), a small guanosinetriphosphate (GTP)-binding protein of the Ras superfamily. The specific siRNA targeting ARF6 markedly inhibited HBMECs susceptibility to EV71. EV71 infectivity was inhibited by NAV-2729, a specific inhibitor of ARF6, in a dose-dependent manner. The subcellular analysis demonstrated the co-localization of the endocytosed EV71 and ARF6, while knockdown of ARF6 with siRNA remarkably influenced EV71 endocytosis. By immunoprecipitation assays, we found a direct interaction of ARF6 with EV71 viral protein. Furthermore, ARF1, another small GTP-binding protein, was also found to participate in ARF6-mediated EV71 endocytosis. Murine experiments demonstrated that NAV-2729 significantly alleviated mortality caused by EV71 infection. Our study revealed a new pathway by which EV71 enters the HBMECs and provides new targets for drug development.

Application of the double bounded dichotomous choice model to the estimation of parent's willingness to pay for the hand foot mouth disease vaccination: A survey in Selangor, Malaysia

Hand foot and mouth disease (HFMD) is a notifiable viral disease in Malaysia, and is transmitted primarily among young children. Although vaccines for enteroviruses 71 (EV-71) were approved in China against HFMD, the availability and the acceptance of the vaccine in the Malaysia are unknown. This study investigated and ascertained the determinants of willingness-to-pay (WTP) for HFMD vaccination in Selangor Malaysia. This study adopted a cross-sectional, contingent valuation method involving 390 parents of young children aged six and below. The double bounded dichotomous choice (DBDC) approach was employed to assess the WTP for HFMD vaccine among respondents. A bivariate probit model was used to assess the key determinants of WTP for HFMD vaccine, while the mean WTP was measured using the Krinsky and Robb procedure. We found that 279 (71.5%) of parents were willing to pay for the HFMD vaccination. The estimated single bounded mean WTP was MYR460.23 (equivalent to US$ 102.17) for two doses of HFMD vaccination. The double bounded analysis revealed that the vaccine's price, poor education background and lower income were the key factors that significantly affected the WTP, with the estimated mean WTP being MYR394.00 (US$ 87.47). In conclusion, most Malaysian parents are willing to pay for the HFMD vaccination. The estimated WTP identifies the optimal price point for HFMD vaccination in Malaysia. Furthermore, the government should focus on an awareness programme for the HFMD vaccination among parents who have lower income or education level.

The Pivotal Role of Galectin-3 in Viral Infection: A Multifaceted Player in Host-Pathogen Interactions

Galectin-3 (Gal-3), a beta-galactoside-binding lectin, plays a pivotal role in various cellular processes, including immune responses, inflammation, and cancer progression. This comprehensive review aims to elucidate the multifaceted functions of Gal-3, starting with its crucial involvement in viral entry through facilitating viral attachment and catalyzing internalization. Furthermore, Gal-3 assumes significant roles in modulating immune responses, encompassing the activation and recruitment of immune cells, regulation of immune signaling pathways, and orchestration of cellular processes such as apoptosis and autophagy. The impact of Gal-3 extends to the viral life cycle, encompassing critical phases such as replication, assembly, and release. Notably, Gal-3 also contributes to viral pathogenesis, demonstrating involvement in tissue damage, inflammation, and viral persistence and latency elements. A detailed examination of specific viral diseases, including SARS-CoV-2, HIV, and influenza A, underscores the intricate role of Gal-3 in modulating immune responses and facilitating viral adherence and entry. Moreover, the potential of Gal-3 as a biomarker for disease severity, particularly in COVID-19, is considered. Gaining further insight into the mechanisms and roles of Gal-3 in these infections could pave the way for the development of innovative treatment and prevention options for a wide range of viral diseases.

Viral meningitis and encephalitis: an update

PURPOSE OF REVIEW

The most common infectious etiologies of meningitis and encephalitis are viruses. In this review, we will discuss current epidemiology, prevention, diagnosis, and treatment of the most common causes of viral meningitis and encephalitis worldwide.

RECENT FINDINGS

Viral meningitis and encephalitis are increasingly diagnosed as molecular diagnostic techniques and serologies have become more readily available worldwide but recent progress in novel antiviral therapies remains limited. Emerging and re-emerging viruses that have caused endemic or worldwide outbreaks or epidemics are arboviruses (e.g., West Nile virus, Japanese encephalitis, Tick borne encephalitis, Dengue, Zika, Toscana), enteroviruses (e.g., Enterovirus 71, Enterovirus D68), Parechoviruses, respiratory viruses [e.g., severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza, metapneumoviruses, measles, mumps], and herpes viruses [e.g., herpes simplex virus (HSV) type 1 (HSV-1), HSV-2, human herpes (HV) 6, varicella zoster virus (VZV)]. Future efforts should concentrate in increasing availability for those viruses with effective vaccination [e.g., Japanese encephalitis, Tick borne encephalitis, varicella zoster viruses, SARS-CoV-2, influenza], prompt initiation of those with encephalitis with treatable viruses (e.g., HSV-1, VZV), increasing the diagnostic yield by using novel techniques such as metagenomic sequencing and avoiding unnecessary antibiotics in those with viral meningitis or encephalitis.

SUMMARY

We review the current epidemiology, clinical presentation, diagnosis, and treatment of the common causative agents of viral meningitis and encephalitis worldwide.

Hand-Foot-and-Mouth Disease-Associated Enterovirus and the Development of Multivalent HFMD Vaccines

Hand-foot-and-mouth disease (HFMD) is an infectious disease of children caused by more than 20 types of enteroviruses, with most cases recovering spontaneously within approximately one week. Severe HFMD in individual children develops rapidly, leading to death, and is associated with other complications such as viral myocarditis and type I diabetes mellitus. The approval and marketing of three inactivated EV-A71 vaccines in China in 2016 have provided a powerful tool to curb the HFMD epidemic but are limited in cross-protecting against other HFMD-associated enteroviruses. This review focuses on the epidemiological analysis of HFMD-associated enteroviruses since the inactivated EV-A71 vaccine has been marketed, collates the progress in the development of multivalent enteroviruses vaccines in different technical routes reported in recent studies, and discusses issues that need to be investigated for safe and effective HFMD multivalent vaccines.

Enterovirus 71-Induced Autoimmune Hemolytic Anemia in a Boy

Autoimmune hemolytic anemia (AIHA) can be induced by recent or concomitant infections. Many infectious agents are postulated to be associated with this condition. Treatment of infection induced AIHA still varies. This report describes a previously healthy Thai boy who developed AIHA associated with enterovirus-71 infection. He was successfully treated with oral prednisone.