The Genomic Characterization of Enterovirus D68 from 2011 to 2015 in Beijing, China

A retrospective surveillance study on enterovirus D68 was performed in Beijing, China, following the largest and most widespread EV-D68 infection, which occurred in the USA. From January 2011 to July 2015, EV-D68 was identified in 12 individuals with respiratory infections in Beijing, China. The phylogenetic relationships based on the genomic sequence alignment showed that there were two lineages circulating in Beijing from 2011 to 2015. Eight EV-D68 strains belonged to group 1 and four belonged to group 3. All EV-D68 strains from Beijing in 2014 were separately clustered into subgroup II of group 1. Based on these results, we concluded that the Beijing EV-D68 strains had little association with the EV-D68 strains circulating in the 2014 USA outbreak.

Acute flaccid paralysis and neurogenic respiratory failure associated with enterovirus D68 infection in children: Report of two cases

BACKGROUND Acute flaccid paralysis(AFP)and neurogenic respiratory failure rarely occur in children.At the end of 2018,some children with such symptoms were admitted to our hospital.In this study,we aimed to assess two children with AFP and neurogenic respiratory failure associated with enterovirus D68(EV-D68).CASE SUMMARY Two children admitted to our hospital presented with symptoms and imaging results different from those of acute disseminated encephalomyelitis and hand,foot,and mouth disease.Their main symptoms were AFP and neurogenic respiratory failure.Magnetic resonance imaging showed severe inflammatory injury mainly to the anterior horn cells of the spinal cord.Blood and cerebrospinal fluid samples were collected to assess for pathogens,including bacteria,tuberculosis,cryptococcus,herpes virus,and coxsackie virus,and the results were negative.At the beginning,the two cases were not assessed for EV-D68 in the nasopharyngeal,blood,and cerebrospinal fluid specimens.About 2 mo later,EVD68 was detected in the stool sample of one of the cases.The symptom of AFP was caused by injury to the anterior horn cells at levels C5-L5 of the spinal cord,while neurogenic respiratory failure was at levels C3-C5.CONCLUSION We should pay attention to the detection and diagnosis of EV-D68 and make efforts to develop antivirus drugs and vaccines.

Chronic Enterovirus D68 Bronchiolitis Causing Severe Respiratory Insufficiency

Human enteroviruses are less well-known causes of acute bronchiolitis. In recent years, Enterovirus D68 [EV D68] has emerged as significant cause of epidemic viral bronchiolitis and pneumonia in the United States and other countries. Chronic bronchiolitis has not been previously attributed to EV D68. We documented EV D68 in open lung biopsies of a young adult patient who was frequently admitted to the hospital for severe exacerbation of respiratory infections and subsequently developed progressive respiratory insufficiency. The difficulty of diagnosis and potential economic impact of this illness is discussed.

Caspase-8 activation regulates enterovirus D68 infection-induced inflammatory response and cell death

Enterovirus D68 (EV-D68) infection causes severe acute respiratory infection and severe neurological complications, such as acute flaccid myelitis (AFM), in children. However, although EV-D68 has pandemic potential, no effective drugs or vaccines are currently clinically available. Furthermore, EV-D68 infection-induced inflammatory response and cell death are not fully understood. In this study, we demonstrated that several inflammatory cytokines were upregulated in a multiplicity of infection (MOI) dependent manner in EV-D68-infected human rhabdomyosarcoma (RD) cells. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) confirmed that tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), C-C motif chemokine ligand-5 (CCL-5), and CXC motif chemokine ligand-5 (CXCL-5) mRNA levels were highly upregulated after EV-D68 infection. IL-1β processing and maturation mediated by caspase-8 was inhibited by the caspase-8 inhibitor Z-IETD-FMK. EV-D68 infection activates caspase-8 to mediate IL-1β maturation and secretion. Additionally, EV-D68 activated cell death-related proteins such as caspase-3, poly (ADP-ribose) polymerase 1 (PARP-1), phosphorylation of Mixed Lineage Kinase domain-like protein (pMLKL), and gasdermin E (GSDME). Thus, EV-D68 infection activates caspase-8, which triggers the necroptosis and apoptosis pathways. Overall, our data suggest that caspase-8 activation is associated with the inflammatory response and cell death in EV-D68-infected RD cells. This mechanism represents a novel target for the treatment of EV-D68 infection by inhibiting caspase-8 activation.

Enterovirus D68 infection upregulates SOCS3 expression to inhibit JAK-STAT3 signaling and antagonize the innate interferon response of the host

Enterovirus D68(EV-D68)can cause respiratory diseases and acute flaccid paralysis,posing a great threat to public health.Interferons are cytokines secreted by host cells that have broad-spectrum antiviral effects,inducing the expression of hundreds of interferon-stimulated genes(ISGs).EV-D68 activates ISG expression early in infection,but at a later stage,the virus suppresses ISG expression,a strategy evolved by EV-D68 to antagonize interferons.Here,we explore a host protein,suppressor of cytokine signaling 3(SOCS3),is upregulated during EV-D68 infection and antagonizes the antiviral effects of type I interferon.We subsequently demonstrate that the structural protein of EV-D68 upregulated the expression of RFX7,a transcriptional regulator of SOCS3,leading to the upregulation of SOCS3 expression.Further exploration revealed that SOCS3 plays its role by inhibiting the phosphorylation of signal transducer and activator of transcription 3(STAT3).The expression of SOCS3 inhibited the expression of ISG,thereby inhibiting the antiviral effect of type I interferon and promoting EV-D68 transcription,protein production,and viral titer.Notably,a truncated SOCS3,generated by deleting the kinase inhibitory region(KIR)domain,failed to promote replication and translation of EV-D68.Based on the above studies,we designed a short peptide named SOCS3 inhibitor,which can specifically bind and inhibit the KIR structural domain of SOCS3,significantly reducing the RNA and protein levels of EV-D68.In summary,our results demonstrated a novel mechanism by which EV-D68 inhibits ISG transcription and antagonizes the antiviral responses of host type I interferon.