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Coxsackievirus infections [keywords]
- ER stress, autophagy, and RNA viruses. [Journal Article, Review]
- Front Microbiol 2014.:388.
Endoplasmic reticulum (ER) stress is a general term for representing the pathway by which various stimuli affect ER functions. ER stress induces the evolutionarily conserved signaling pathways, called the unfolded protein response (UPR), which compromises the stimulus and then determines whether the cell survives or dies. In recent years, ongoing research has suggested that these pathways may be linked to the autophagic response, which plays a key role in the cell's response to various stressors. Autophagy performs a self-digestion function, and its activation protects cells against certain pathogens. However, the link between the UPR and autophagy may be more complicated. These two systems may act dependently, or the induction of one system may interfere with the other. Experimental studies have found that different viruses modulate these mechanisms to allow them to escape the host immune response or, worse, to exploit the host's defense to their advantage; thus, this topic is a critical area in antiviral research. In this review, we summarize the current knowledge about how RNA viruses, including influenza virus, poliovirus, coxsackievirus, enterovirus 71, Japanese encephalitis virus, hepatitis C virus, and dengue virus, regulate these processes. We also discuss recent discoveries and how these will produce novel strategies for antiviral treatment.
- Coxsackievirus can persist in murine pancreas by deletion of 5' terminal genomic sequences. [JOURNAL ARTICLE]
- J Med Virol 2014 Aug 11.
Enterovirus infections are generally acute and rapidly cleared by the host immune response. Enteroviruses can at times persist in immunologically intact individuals after the rise of the type-specific neutralizing immune response. The mechanism of enterovirus persistence was shown in group B coxsackieviruses (CVB) to be due to naturally-occurring deletions at the 5' terminus of the genome which variably impact the stem-loop secondary structure called domain I. These deletions result in much slower viral replication and a loss of measurable cytopathic effect when such 5' terminally deleted (TD) viruses are assayed in cell culture. The existence and persistence of CVB-TD long after the acute phase of infection has been documented in hearts of experimentally inoculated mice and naturally infected humans but to date, the existence of TD enteroviral populations have not been documented in any other organ. Enteroviral infections have been shown to impact type 1 diabetes (T1D) onset in humans as well as in the non-obese diabetic mouse model of T1D. The first step to studying the potential impact of CVB-TD on T1D etiology is to determine whether CVB-TD populations can arise in the pancreas. After inoculation of NOD diabetic mice with CVB, viral RNA persists in the absence of cytopathic virus in pancreas weeks past the acute infectious period. Analysis of viral genomic 5' termini by RT-PCR showed CVB-TD populations displace the parental population during persistent replication in murine pancreata. J. Med. Virol. 9999: XX-XX, 2014. © 2014 Wiley Periodicals, Inc.
- Induction and suppression of innate antiviral responses by picornaviruses. [JOURNAL ARTICLE]
- Cytokine Growth Factor Rev 2014 Jul 18.
The family Picornaviridae comprises of small, non-enveloped, positive-strand RNA viruses and contains many human and animal pathogens including enteroviruses (e.g. poliovirus, coxsackievirus, enterovirus 71 and rhinovirus), cardioviruses (e.g. encephalomyocarditis virus), hepatitis A virus and foot-and-mouth disease virus. Picornavirus infections activate a cytosolic RNA sensor, MDA5, which in turn, induces a type I interferon response, a crucial component of antiviral immunity. Moreover, picornaviruses activate the formation of stress granules (SGs), large aggregates of preassembled mRNPs (messenger ribonucleoprotein particles) to temporarily store these molecules upon cellular stress. Meanwhile, picornaviruses actively suppress these antiviral responses to ensure efficient replication. In this review we provide an overview of the induction and suppression of the MDA5-mediated IFN-α/β response and the cellular stress pathway by picornaviruses.
- The Impact of Juvenile Coxsackievirus Infection on Cardiac Progenitor Cells and Postnatal Heart Development. [JOURNAL ARTICLE]
- PLoS Pathog 2014 Jul; 10(7):e1004249.
Coxsackievirus B (CVB) is an enterovirus that most commonly causes a self-limited febrile illness in infants, but cases of severe infection can manifest in acute myocarditis. Chronic consequences of mild CVB infection are unknown, though there is an epidemiologic association between early subclinical infections and late heart failure, raising the possibility of subtle damage leading to late-onset dysfunction, or chronic ongoing injury due to inflammatory reactions during latent infection. Here we describe a mouse model of juvenile infection with a subclinical dose of coxsackievirus B3 (CVB3) which showed no evident symptoms, either immediately following infection or in adult mice. However following physiological or pharmacologically-induced cardiac stress, juvenile-infected adult mice underwent cardiac hypertrophy and dilation indicative of progression to heart failure. Evaluation of the vasculature in the hearts of adult mice subjected to cardiac stress showed a compensatory increase in CD31+ blood vessel formation, although this effect was suppressed in juvenile-infected mice. Moreover, CVB3 efficiently infected juvenile c-kit+ cells, and cardiac progenitor cell numbers were reduced in the hearts of juvenile-infected adult mice. These results suggest that the exhausted cardiac progenitor cell pool following juvenile CVB3 infection may impair the heart's ability to increase capillary density to adapt to increased load.
- [Group enterovirus infection due to coxsackievirus A16 in Northwestern Russia]. [English Abstract, Journal Article]
- Zh Mikrobiol Epidemiol Immunobiol 2014 Mar-Apr; (2):51-8.
Study features of epidemic process and etiology of oral cavity and limb enterovirus exanthema group diseases in a number of territories of Northwestern Russia.Isolation and identification of non-poliomyelitis enteroviruses from material of patients was carried out according to WHO recommendations. Phenotyping and phylogenetic analysis of enteroviruses was carried out.In 3 territories of Northwestern Russia oral cavity and limb enterovirus group diseases were registered. Children aged less than 14 years, predominately aged less than 3 years, were shown to be involved in the epidemic process. Coxsackie A16 enteroviruses from 27 samples of patients were isolated in cell cultures and identified by using specific sera. Coxsackie A16 enteroviruses from 16 samples were identified by using partial sequencing of VP1 genome area. Phylogenetic analysis has shown that the identified Coxsackie A16 viruses distributed among 2 phylogenetic groups.Coxsackie A16 enteroviruses that had never been detected in the region previously were established to be the etiologic factor of oral cavity and limb enterovirus exanthema group disease in the 3 territories of Northwestern Russia. The data obtained give evidence on the necessity of epidemiologic and virological control for enterovirus infection with the aim of obtaining novel information on the circulation of non-poliomyelitis enteroviruses in the population and the establishment of development patterns for epidemic process of this infection.
- Identification of Luteolin as Enterovirus 71 and Coxsackievirus A16 Inhibitors through Reporter Viruses and Cell Viability-Based Screening. [JOURNAL ARTICLE]
- Viruses 2014; 6(7):2778-2795.
Hand, foot and mouth disease (HFMD) is a common pediatric illness mainly caused by infection with enterovirus 71 (EV71) and coxsackievirus A16 (CA16). The frequent HFMD outbreaks have become a serious public health problem. Currently, no vaccine or antiviral drug for EV71/CA16 infections has been approved. In this study, a two-step screening platform consisting of reporter virus-based assays and cell viability‑based assays was developed to identify potential inhibitors of EV71/CA16 infection. Two types of reporter viruses, a pseudovirus containing luciferase-encoding RNA replicons encapsidated by viral capsid proteins and a full-length reporter virus containing enhanced green fluorescent protein, were used for primary screening of 400 highly purified natural compounds. Thereafter, a cell viability-based secondary screen was performed for the identified hits to confirm their antiviral activities. Three compounds (luteolin, galangin, and quercetin) were identified, among which luteolin exhibited the most potent inhibition of viral infection. In the cell viability assay and plaque reduction assay, luteolin showed similar 50% effective concentration (EC50) values of about 10 μM. Luteolin targeted the post-attachment stage of EV71 and CA16 infection by inhibiting viral RNA replication. This study suggests that luteolin may serve as a lead compound to develop potent anti-EV71 and CA16 drugs.
- Enterovirus/Picornavirus infections. [Journal Article]
- Handb Clin Neurol 2014.:379-416.
The human enteroviruses (EV) comprise one group of the picornavirus family. The best known members are the polioviruses (PV), coxsackieviruses, and echoviruses. They replicate in the oropharynx and gastrointestinal (GI) tract and are primarily spread by fecal-hand-oral contamination. With systemic invasion nonspecific febrile illness occurs as well as specific syndromes (rashes, hand-foot-and-mouth disease, herpangina, pleurodynia, myocarditis/pericarditis, and conjunctivitis). With systemic replication a high level viremia may result in central nervous system (CNS) invasion. EV activity can be endemic in warm climates or epidemic in temperate climates. In temperate climates, because of improved hygiene, newborns were not exposed to EV until they were older, resulting in large epidemics of poliomyelitis, which were finally curtailed with the killed PV vaccines in the 1950s and the live oral PV vaccines in the 1960s. Today, "aseptic" meningitis is the most common neurologic syndrome caused by EV. EV are also the most common cause of viral meningitis. Other EV neurologic syndromes include encephalitis, paralytic disease, persistent infections, and the severe group B coxsackievirus fatal systemic infections of neonates. Newly recognized emerging infections include EV71 rhombencephalitis/brainstem encephalitis and saffold virus (Saf V) meningitis and cerebellitis. Diagnostic clues can come from epidemics, systemic manifestations, household infections, the cerebrospinal fluid picture, and the neurologic syndromes. However, definite diagnosis depends on laboratory methods, primarily nucleic acid amplification. Treatment of acute infections is supportive. Preventive methods include good hygiene and aggressive polio vaccination programs.
- Immunogenicity Studies of Bivalent Inactivated Virions of EV71/CVA16 Formulated with Submicron Emulsion Systems. [Journal Article]
- Biomed Res Int 2014.:670506.
We assessed two strategies for preparing candidate vaccines against hand, foot, and mouth disease (HFMD) caused mainly by infections of enterovirus (EV) 71 and coxsackievirus (CV) A16. We firstly design and optimize the potency of adjuvant combinations of emulsion-based delivery systems, using EV71 candidate vaccine as a model. We then perform immunogenicity studies in mice of EV71/CVA16 antigen combinations formulated with PELC/CpG. A single dose of inactivated EV71 virion (0.2 μ g) emulsified in submicron particles was found (i) to induce potent antigen-specific neutralizing antibody responses and (ii) consistently to elicit broad antibody responses against EV71 neutralization epitopes. A single dose immunogenicity study of bivalent activated EV71/CVA16 virion formulated with either Alum or PELC/CpG adjuvant showed that CVA16 antigen failed to elicit CVA16 neutralizing antibody responses and did not affect EV71-specific neutralizing antibody responses. A boosting dose of emulsified EV71/CVA16 bivalent vaccine candidate was found to be necessary to achieve high seroconversion of CVA16-specific neutralizing antibody responses. The current results are important for the design and development of prophylactic vaccines against HFMD and other emerging infectious diseases.
- Increased IFN-α-Producing Plasmacytoid Dendritic Cells (pDCs) in Human Th1-Mediated Type 1 Diabetes: pDCs Augment Th1 Responses through IFN-α Production. [JOURNAL ARTICLE]
- J Immunol 2014 Jun 27.
Increasing evidence suggests that type 1 IFN (IFN-αβ) is associated with pathogenesis of Th1-mediated type 1 diabetes (T1D). A major source of IFN-αβ is plasmacytoid dendritic cells (pDCs). In this study, we analyzed peripheral blood pDC numbers and functions in at-risk, new-onset, and established T1D patients and controls. We found that subjects at risk for T1D and new-onset and established T1D subjects possessed significantly increased pDCs but similar number of myeloid DCs when compared with controls. pDC numbers were not affected by age in T1D subjects but declined with increasing age in control subjects. It was demonstrated that IFN-α production by PBMCs stimulated with influenza viruses was significantly higher in T1D subjects than in controls, and IFN-α production was correlated with pDC numbers in PBMCs. Of interest, only T1D-associated Coxsackievirus serotype B4 but not B3 induced majority of T1D PBMCs to produce IFN-α, which was confirmed to be secreted by pDCs. Finally, in vitro studies demonstrated IFN-α produced by pDCs augmented Th1 responses, with significantly greater IFN-γ-producing CD4(+) T cells from T1D subjects. These findings indicate that increased pDCs and their IFN-αβ production may be associated with this Th1-mediated autoimmune disease, especially under certain viral infections linked to T1D pathogenesis.
- Coxsackievirus A 16 infection does not interfere with the specific immune response induced by an enterovirus 71 inactivated vaccine in rhesus monkeys. [JOURNAL ARTICLE]
- Vaccine 2014 Jun 20.
Hand, foot and mouth disease is usually caused by enterovirus 71 (EV71) and coxsackievirus A 16 (CA16), which are members of the Picornaviridae family. In the present study, the characteristics of the immune response induced by an EV71 inactivated vaccine (made from human diploid cells) were explored in the presence of CA16 infection, based on the previously established neonatal rhesus monkey model. The typical clinical manifestations, including body temperature, viral viremia and virus shedding in the mouth, pharynx and feces, were characterized. A specific neutralizing antibody assay showed that the specific immune response induced by the EV71 inactivated vaccine was active against EV71 but not against CA16. No remarkable fluctuation in proinflammatory cytokine release was identified in the serum of immunized monkeys with EV71 vaccine and CA16 infections subsequently. The results showed that the specific immune response induced by the EV71 inactivated vaccine is effective against EV71 infection but is not affected by CA16 infection.