B3 Infection Research Articles

PAR1 regulation of CXCL1 expression and neutrophil recruitment to the lung in mice infected with influenza A virus

BackgroundProtease‐activated receptor 1 (PAR1) is expressed in various immune cells and in the lung. We showed that PAR1 plays a role in Coxsackievirus B3 infection by enhancing toll‐like receptor 3‐dependent interferon‐β expression in cardiac fibroblasts. ObjectivesWe investigated the role of PAR1 in a mouse model of influenza A virus (IAV) infection. MethodsWe used mice with either a global deficiency of PAR1, cell type‐specific deficiencies of PAR1, or mutation of PAR1 at the R41 or R46 cleavage sites. ResultsPAR1‐deficient mice had increased CXCL1 expression in the lung, increased neutrophil recruitment, increased protein levels in the bronchoalveolar lavage fluid, and increased mortality after IAV infection compared with control mice infected with IAV. Results from mice with cell type‐specific deletion of PAR1 indicated that PAR1 expression by hematopoietic cells suppressed CXCL1 expression, whereas PAR1 expression by endothelial cells enhanced CXCL1 expression in response to IAV infection. PAR1 activation also enhanced polyinosinic:polycytodylic acid induction of interleukin‐8 in a human endothelial cell line. Mutation of the R46 cleavage site of PAR1 was associated with increased CXCL1 expression in the lung in response to IAV infection, which suggested that R46 signaling suppresses CXCL1 expression. ConclusionsThese results indicate that PAR1 expression by different cell types and activation by different proteases modulates the immune response during IAV infection.

Modeling the complete kinetics of coxsackievirus B3 reveals human determinants of host-cell feedback.

Complete kinetic models are pervasive in chemistry but lacking in biological systems. We encoded the complete kinetics of infection for coxsackievirus B3 (CVB3), a compact and fast-acting RNA virus. The model consists of separable, detailed modules describing viral binding-delivery, translation-replication, and encapsidation. Specific module activities are dampened by the type I interferon response to viral double-stranded RNAs (dsRNAs), which is itself disrupted by viral proteinases. The experimentally validated kinetics uncovered that cleavability of the dsRNA transducer mitochondrial antiviral signaling protein (MAVS) becomes a stronger determinant of viral outcomes when cells receive supplemental interferon after infection. Cleavability is naturally altered in humans by a common MAVS polymorphism, which removes a proteinase-targeted site but paradoxically elevates CVB3 infectivity. These observations are reconciled with a simple nonlinear model of MAVS regulation. Modeling complete kinetics is an attainable goal for small, rapidly infecting viruses and perhaps viral pathogens more broadly. A record of this paper's transparent peer review process is included in the Supplemental information.

Development of antiviral therapeutics combating coxsackievirus type B3 infection

Enteroviruses comprise highly diverse group of single-stranded positive RNA viruses belonging to Enterovirus genus, Picornaviridae family. They are the most prevalent viruses worldwide highlighted by high resistance to environmental cues. Enteroviruses normally cause seasonal self-limiting infections, but also known as causative infectious agents of encephalitis, myocarditis, poliomyelitis, acute heart failure and sepsis. Enterovirus genetic plasticity contributes to widespread epidemics and sporadic outbreaks (e. g., outbreaks of Enterovirus D68 and Enterovirus 71). Type B Coxsackieviruses of Enterovirus B species is one of commonly identified infectious agents associated predominantly with mild upper respiratory and gastrointestinal illnesses. Nevertheless, Coxsackieviruses B3 infection can result in severe myocarditis leading ultimately to heart failure. The pathogenesis of Coxsackievirus B3-induced myocarditis is well known being mediated by both direct damage due to viral proteases and indirectly via secondary host immune responses. Despite success in preventive vaccination of some enterovirus infections that allowed to control some of them direct antiviral agents for treatment of enteroviral infection particularly Coxsackieviruses B3 myocardial infection are still in demand. In addition, no ongoing clinical trials for therapy or prevention of Coxsackieviruses B3 infection are available. Current treatment strategies are mainly aimed to stabilize patient condition and relieve discomfort condition. It seems that relatively small market for anti-enteroviral drugs prevents pharma industry from developing new drugs. The Coxsackieviruses B3 lifecycle have been extensively studied and potential targets for drug design have been identified. The aim of our review was to describe current state in the field of antiviral drug design combating Coxsackieviruses B3 infection emphasizing direct-acting antivirals, albeit paying some attention to host factor-targeting inhibitors (including compounds from medicinal plant extracts) as well. The following categories of direct Coxsackieviruses B3 inhibitors are discussed in detail: capsid binders (pleconaril and its derivatives), viral 3C protease inhibitors (rupintrivir and its analogs), drugs targeting viral replication (both nucleoside analogs and non-nucleoside inhibitors). Results of drug repurposing screens for amiloride, benzerazide, dibucaine and fluoxetine are also discussed.

A Crucial Role of ACBD3 Required for Coxsackievirus Infection in Animal Model Developed by AAV-Mediated CRISPR Genome Editing Technique.

Genetic screens using CRISPR/Cas9 have been exploited to discover host–virus interactions. These screens have identified viral dependencies on host proteins during their life cycle and potential antiviral strategies. The acyl-CoA binding domain containing 3 (ACBD3) was identified as an essential host factor for the Coxsackievirus B3 (CVB3) infection. Other groups have also investigated the role of ACBD3 as a host factor for diverse enteroviruses in cultured cells. However, it has not been tested if ACBD3 is required in the animal model of CVB3 infection. Owing to embryonic lethality, conventional knockout mice were not available for in vivo study. As an alternative approach, we used adeno-associated virus (AAV)-mediated CRISPR genome editing to generate mice that lacked ACBD3 within the pancreas, the major target organ for CVB3. Delivery of sgRNAs using self-complementary (sc) AAV8 efficiently induced a loss-of-function mutation in the pancreas of the Cas9 knock-in mice. Loss of ACBD3 in the pancreas resulted in a 100-fold reduction in the CVB3 titer within the pancreas and a noticeable reduction in viral protein expression. These results indicate a crucial function of ACBD3 in CVB3 infection in vivo. AAV-mediated CRISPR genome editing may be applicable to many in vivo studies on the virus–host interaction and identify a novel target for antiviral therapeutics.

Coxsackievirus B3 Infection of Human iPSC Lines and Derived Primary Germ-Layer Cells Regarding Receptor Expression.

The association of members of the enterovirus family with pregnancy complications up to miscarriages is under discussion. Here, infection of two different human induced pluripotent stem cell (iPSC) lines and iPSC-derived primary germ-layer cells with coxsackievirus B3 (CVB3) was characterized as an in vitro cell culture model for very early human development. Transcriptomic analysis of iPSC lines infected with recombinant CVB3 expressing enhanced green fluorescent protein (EGFP) revealed a reduction in the expression of pluripotency genes besides an enhancement of genes involved in RNA metabolism. The initial distribution of CVB3-EGFP-positive cells within iPSC colonies correlated with the distribution of its receptor coxsackie- and adenovirus receptor (CAR). Application of anti-CAR blocking antibodies supported the requirement of CAR, but not of the co-receptor decay-accelerating factor (DAF) for infection of iPSC lines. Among iPSC-derived germ-layer cells, mesodermal cells were especially vulnerable to CVB3-EGFP infection. Our data implicate further consideration of members of the enterovirus family in the screening program of human pregnancies. Furthermore, iPSCs with their differentiation capacity into cell populations of relevant viral target organs could offer a reliable screening approach for therapeutic intervention and for assessment of organ-specific enterovirus virulence.

Two Natural Recombination gave rise to the Coxsackievirus B3 GV that triggered outbreaks in China in 2006 - 2012

Coxsackievirus B3 serotype GV caused the epidemic of Coxsackievirus B3 infection in China from 2006 to 2012. To study the evolution and recombination of Coxsackievirus B3 serotype GV, we performed recombination and phylogenetic analysis of 499 complete genomes of Enterovirus B available in GenBank, dated April 2019. Results indicated that most of the strains of Coxsackievirus B3 GV in P1 region were derived from a Coxsackievirus B3 GVI parent, and in P2-3 region from EchoV E25 strain, with nucleotide identities of 97.2% and 94.7%, respectively. Other strains of Coxsackievirus B3 GV-C1 in P1-P2 regions were derived from Coxsackievirus B3 GV-C3, whereas those in P3 regions were from CVB5. These naturally occurring recombination events were confirmed by phylogenetic analysis. This study indicates that two naturally occurring recombination gave rise to the coxsackievirus B3 GV that triggered outbreaks in China in 2006 - 2012.

MicroRNA-30a Modulates Type I Interferon Responses to Facilitate Coxsackievirus B3 Replication Via Targeting Tripartite Motif Protein 25.

Viral myocarditis is caused by a viral infection and characterized by the inflammation of the myocardium. Coxsackievirus B3 (CVB3) infection is one of the most common among the infections caused by this virus. The host’s early innate immune response to CVB3 infection particularly depends on the functions of type I interferons (IFNs). In this study, we report that a host microRNA, miR-30a, was upregulated by CVB3 to facilitate its replication. We demonstrated that miR-30a was a potent negative regulator of IFN-I signaling by targeting tripartite motif protein 25 (TRIM25). In addition, we found that TRIM25 overexpression significantly suppressed CVB3 replication, whereas TRIM25 knockdown increased viral titer and VP1 protein expression. MiR-30a inhibits the expression of TRIM25 and TRIM25-mediated retinoic acid-inducible gene (RIG)-I ubiquitination to suppress IFN-β activation and production, thereby resulting in the enhancement of CVB3 replication. These results indicate the proviral role of miR-30a in modulating CVB3 infection for the first time. This not only provides a new strategy followed by CVB3 in order to modulate IFN-I–mediated antiviral immune responses by engaging host miR-30a but also improves our understanding of its pathogenesis.

Coxsackievirus B3 Infection Early in Pregnancy Induces Congenital Heart Defects Through Suppression of Fetal Cardiomyocyte Proliferation.

BackgroundCoxsackievirus B (CVB) is the most common cause of viral myocarditis. It targets cardiomyocytes through coxsackie and adenovirus receptor, which is highly expressed in the fetal heart. We hypothesized CVB3 can precipitate congenital heart defects when fetal infection occurs during critical window of gestation.Methods and ResultsWe infected C57Bl/6 pregnant mice with CVB3 during time points in early gestation (embryonic day [E] 5, E7, E9, and E11). We used different viral titers to examine possible dose‐response relationship and assessed viral loads in various fetal organs. Provided viral exposure occurred between E7 and E9, we observed characteristic features of ventricular septal defect (33.6%), abnormal myocardial architecture resembling noncompaction (23.5%), and double‐outlet right ventricle (4.4%) among 209 viable fetuses examined. We observed a direct relationship between viral titers and severity of congenital heart defects, with apparent predominance among female fetuses. Infected dams remained healthy; we did not observe any maternal heart or placental injury suggestive of direct viral effects on developing heart as likely cause of congenital heart defects. We examined signaling pathways in CVB3‐exposed hearts using RNA sequencing, Kyoto Encyclopedia of Genes and Genomes enrichment analysis, and immunohistochemistry. Signaling proteins of the Hippo, tight junction, transforming growth factor‐β1, and extracellular matrix proteins were the most highly enriched in CVB3‐infected fetuses with ventricular septal defects. Moreover, cardiomyocyte proliferation was 50% lower in fetuses with ventricular septal defects compared with uninfected controls.ConclusionsWe conclude prenatal CVB3 infection induces congenital heart defects. Alterations in myocardial proliferate capacity and consequent changes in cardiac architecture and trabeculation appear to account for most of observed phenotypes.

CD11b is involved in coxsackievirus B3-induced viral myocarditis in mice by inducing Th17 cells.

Viral myocarditis (VMC) caused by coxsackievirus B3 (CVB3) infection is a life-threatening disease. The cardiac damage during VMC is not mainly due to the direct cytotoxic effect of the virus on cardiomyocytes but mostly involves the induction of immune responses. Integrin CD11b plays an important role in immune response, for instance, in the induction of Th17 cells. However, the role of CD11b in the pathogenesis of VMC remains largely unknown. In the present study, a mouse model of VMC was established by CVB3 infection and CD11b was knocked down in the VMC mice by transfection with siRNA-CD11b. The expression of CD11b and IL-17 in heart tissues, frequency of Th17 cells in spleen tissues and serum IL-17 levels were measured using quantitative RT-PCR, Western blot, immunohistochemistry, flow cytometry and ELISA. Results showed that CVB3 infection caused the pathological changes in heart tissues with the increases in the following indexes: expression of CD11b and IL-17 in heart tissues, frequency of Th17 cells in spleen tissues and serum IL-17 levels. The expression of CD11b was positively correlated with IL-17 expression in heart tissues. Depletion of CD11b attenuated the damage caused by CVB3 and decreased the frequency of Th17 cells in spleen tissues as well as in IL-17, IL-23 and STAT3 expression in heart tissues. In summary, our findings reveal that disruption of CD11b function reduced CVB3-induced myocarditis, suggesting that CD11b may be a novel therapeutic target for VMC.

Genome-wide association study of the TP53 R249S mutation in hepatocellular carcinoma with aflatoxin B1 exposure and infection with hepatitis B virus.

Exposure to dietary aflatoxin B1 (AFB1) induces DNA damage and mutation in the TP53 gene at codon 249, known as the TP53 R249S mutation, and is a major risk factor for hepatocellular carcinoma (HCC). AFB1 and the hepatitis B virus (HBV) together exert synergistic effects that promote carcinogenesis and TP53 R249S mutation in HCC. A genome-wide association study (GWAS) of whole genome exons was conducted using 485 HCC patients with chronic HBV infection. This was followed by an independent replication study conducted using 270 patients with chronic HBV infection. Immunohistochemistry was used to evaluate TP53 expression in all samples. This showed a correlation between codon 249 mutations and TP53 expression. Susceptibility variants for the TP53 R249S mutation in HCC were identified based on both the GWAS and replication study. The associations between identified variants and the expression levels of their located genes were analyzed in 20 paired independent samples. The likelihood of positive TP53 expression was found to be higher in HCC patients with the R249S mutation both in the GWAS (P<0.001) and the replication study (P=0.006). The combined analyses showed that the TP53 R249S mutation was significantly associated with three single nucleotide polymorphisms (SNPs): ADAMTS18 rs9930984 (adjusted P=4.84×10-6), WDR49 rs75218075 (adjusted P=7.36×10-5), and SLC8A3 rs8022091 (adjusted P=0.042). The TP53 R249S mutation was found to be highly associated with the TT genotypes of rs9930984 (additive model, P=0.01; dominant model, P=6.43×10-5) and rs75218075 (additive model, P=0.002; dominant model, P=2.16×10-4). Additionally, ADAMTS18 mRNA expression was significantly higher in HCC tissue compared with its expression in paired non-tumor tissue (P=0.041), and patients carrying the TT genotype at rs9930984 showed lower ADAMTS18 expression in non-tumor tissue compared with patients carrying the GT genotype (P=0.0028). WDR49 expression was markedly lower in HCC tissue compared with paired non-tumor tissue (P=0.0011). TP53 expression is significantly associated with the R249S mutation in HCC. Our collective results suggest that rs9930984, rs75218075, and rs8022091 are associated with R249S mutation susceptibility in HCC patients exposed to AFB1 and HBV infection.

Kruppel-like factor 10 protects against acute viral myocarditis by negatively regulating cardiac MCP-1 expression

Viral myocarditis (VMC) is a cardiac disease associated with myocardial inflammation and injury induced by virus infection. Cardiomyocytes have recently been regarded as key players in eliciting and modulating inflammation within the myocardium. Kruppel-like factor 10 (KLF10) is a crucial regulator of various pathological processes and plays different roles in a variety of diseases. However, its role in VMC induced by coxsackievirus B3 (CVB3) infection remains unknown. In this study, we report that cardiac KLF10 confers enhanced protection against viral myocarditis. We found that KLF10 expression was downregulated upon CVB3 infection. KLF10 deficiency enhanced cardiac viral replication and aggravated VMC progress. Bone marrow chimera experiments indicated that KLF10 expression in nonhematopoietic cells was involved in the pathogenesis of VMC. We further identified MCP-1 as a novel target of KLF10 in cardiomyocytes, and KLF10 cooperated with histone deacetylase 1 (HDAC1) to negatively regulate MCP-1 expression by binding its promoter, leading to activation of MCP-1 transcription and recruitment of Ly6Chigh monocytes/macrophages into the myocardium. This novel mechanism of MCP-1 regulation by KLF10 might provide new insights into the pathogenesis of VMC and a potential therapeutic target for VMC.

Clinical characteristics of echovirus 11 and coxsackievirus B5 infections in Taiwanese children requiring hospitalization.

Severe illness can occur in young children infected with certain types of enteroviruses including echovirus 11 (Echo11) and coxsackievirus B5 (CoxB5). The manifestations and outcomes of Echo11 and CoxB5 diseases across all ages of children remained not comprehensively characterized in Taiwan. Culture-confirmed Echo11 (60 patients) or CoxB5 (65 patients) infections were identified in a hospital from 2010 to 2018. The demographics, clinical presentations, laboratory data and outcomes were abstracted and compared between the two viruses infections. Echo11 and CoxB5 was respectively identified in 7 (77.8%) and 2 (22.2%) of 9 calendar years. The median age of all patients was 15 months (range, 1 day-14.5 years). For infants ≤3 months old, Echo11 (23 cases) was associated with higher incidence of aseptic meningitis (35% versus 0%, P=0.003), and a lower rate of upper respiratory tract infections (URI) (22% versus 65%, P=0.004) compared to CoxB5 (20 cases) infections. For patients >3 months old, URI was the cardinal diagnosis (60%) for both viruses. Aseptic meningitis was also more commonly identified in elder children with Echo11 infections (27% versus 11%), though with marginal significance (P=0.07). Acute liver failure was identified in four young infants with Echo11 infections including one neonate dying of severe sepsis and myocarditis. All patients with CoxB5 infections recovered uneventfully. Aseptic meningitis, sepsis-like illness and acute liver failure were more commonly identified in children with Echo11 than those with CoxB5 infections, suggesting greater neurological tropism and virulence toward Echo11.

The Role of Non-coding RNAs in Viral Myocarditis.

Viral myocarditis (VMC) is a disease characterized as myocardial parenchyma or interstitium inflammation caused by virus infection, especially Coxsackievirus B3 (CVB3) infection, which has no accurate non-invasive examination for diagnosis and specific drugs for treatment. The mechanism of CVB3-induced VMC may be related to direct myocardial damage of virus infection and extensive damage of abnormal immune response after infection. Non-coding RNA (ncRNA) refers to RNA that is not translated into protein and plays a vital role in many biological processes. There is expanding evidence to reveal that ncRNAs regulate the occurrence and development of VMC, which may provide new treatment or diagnosis targets. In this review, we mainly demonstrate an overview of the potential role of ncRNAs in the pathogenesis, diagnosis and treatment of CVB3-induced VMC.

291-OR: Deletion within the Helicase 1 Domain of MDA5 Dampens Immune Cell Activation and Delays Type 1 Diabetes

Antiviral responses are associated with triggering type 1 diabetes (T1D) including the synthesis of reactive oxygen species, proinflammatory cytokines, and autoreactive T cell activation. We previously demonstrated that Coxsackievirus B3 (CVB3) infection of Non-Obese Diabetic (NOD) mice accelerates T1D, partly due to the expression of melanoma differentiation-associated protein 5 (MDA5) antiviral sensor. Genetic mutations within human IFIH1, the gene encoding MDA5, are correlated with T1D susceptibility potentially due to increased IFN-α/β synthesis. However, the role of MDA5 in immune cell activation during T1D is unknown. By utilizing mice that lack (NOD.Ifih1KO) or contain a deletion within the helicase 1 domain of MDA5 (NOD.Ifih1ΔHel1), we can test the hypothesis that reduced MDA5 signaling delays T1D by decreasing IFN-α/β synthesis and debilitating islet-infiltrating macrophage and T cell effector responses. We observed that NOD and NOD.Ifih1KO mice develop T1D similarly, but NOD.Ifih1ΔHel1 were significantly protected from spontaneous and CVB3-accelerated T1D. During spontaneous T1D at 12 weeks of age, pancreatic macrophages from NOD.Ifih1ΔHel1 mice have a significant reduction in MHC-II (∼41%) and CD86 (∼43%) expression compared to NOD and NOD.Ifih1KO mice. CVB3-infected NOD.Ifih1ΔHel1 mice exhibited a significant decrease in pancreatic IFN-α (∼54%) and IFN-β (∼67%) synthesis at day 3 post-infection compared to NOD mice. Pancreatic NOD.Ifih1ΔHel1 CD4 and CD8 T cells had reduced T cell activation via CD25 (∼76 and ∼57%) and PD-1 (∼65 and ∼100%) synthesis, respectively, compared to NOD and NOD.Ifih1KO T cells following CVB3 infection. The Ifih1ΔHel1 mutation, but not the Ifih1KO mutation dampened IFN-α/β synthesis, reduced macrophage and T cell activation, and delayed both spontaneous and CVB3-accelerated T1D. Future studies will examine immune differences between NOD.Ifih1ΔHel1 and NOD.Ifih1KO mice that delay or promote autoimmunity, respectively. Disclosure S.I. Blum: None. Y. Chen: None. H.M. Tse: None. Funding American Diabetes Association (7-12-CD-11 to H.M.T.); National Institute of Diabetes and Digestive and Kidney Diseases (DK099550)

Treatment Trends of Myocarditis with Coxsackievirus B3 infection

Viral myocarditis occurred after viral invasion of the cardiocytes and followed by the releasing of viral particles and inflammatory cells. Acute viral myocarditis is relatively common phase of the disease cured spontaneously in some cases or leading to sever acute heart failure and cardiac damage ended with chronic heart failure with increased mortality rate. The fully understand mechanism of viral myocarditis is unclear but some hypothesis trying to illustrate the events of the disease.&#x0D; Regardless of etiological cause, myocarditis is treated depending on disease phase and by following the instructions of Heart Failure Society of America guideline.&#x0D; This article provides the basic knowledge available in literatures to review some important informations of viral myocarditis, with a special focusing on viral myocarditis caused by coxsackievirus B3 infection.

Treatment Trends of Myocarditis with Coxsackievirus B3 infection

Viral myocarditis occurred after viral invasion of the cardiocytes and followed by the releasing of viral particles and inflammatory cells. Acute viral myocarditis is relatively common phase of the disease cured spontaneously in some cases or leading to sever acute heart failure and cardiac damage ended with chronic heart failure with increased mortality rate. The fully understand mechanism of viral myocarditis is unclear but some hypothesis trying to illustrate the events of the disease. Regardless of etiological cause, myocarditis is treated depending on disease phase and by following the instructions of Heart Failure Society of America guideline. This article provides the basic knowledge available in literatures to review some important informations of viral myocarditis, with a special focusing on viral myocarditis caused by coxsackievirus B3 infection.

Coxsackievirus B4 infection and interneuronal spread in primary cultured neurons

Coxsackie B viruses (CV–B) are usually transmitted via the fecal-oral route and the virus gains the central nervous system (CNS) via the bloodstream. Nevertheless, other routes of spread of the virus to the CNS cannot be excluded, including the neuronal route. Neuronal cells, as well as non-neuronal cells (fibroblasts), were isolated from mice and inoculated with CV-B4 in the absence and presence of neutralizing serum. In the absence of neutralizing serum, virus titers recorded in neuron cultures and rates of infected neurons were non-significantly different compared to those recorded in fibroblast cultures. Higher cell mortality was noted among neurons than fibroblasts. The addition of neutralizing serum to neurons did not reduce significantly virus titers or rates of infected cells and cell viability was not significantly augmented, while virus titers and rates of infected fibroblasts were significantly reduced and their viability was significantly enhanced as well. Our results demonstrate the ineffectiveness of neutralizing serum to prevent neurons infection with CV-B4 which suggests a trans-synaptic transmission of CV-B4 between neurons.

Eradication of persistent coxsackievirus B infection from a pancreatic cell line with clinically used antiviral drugs

BackgroundPersistent enterovirus infections create a difficult therapeutic challenge in immunocompromised patients and may also contribute to the development of chronic diseases including type 1 diabetes, cardiomyopathies, post-polio syndrome and chronic fatigue syndrome. ObjectivesTo study the ability of antiviral drugs to eradicate such infection in vitro to evalaute their potential in the treatments of these patients. Study designWe set out to evaluate several licensed or clinically tested drugs which have shown some anti-enterovirus activity in previous studies for their ability to cure persistent infection established by two different coxsackievirus B1 strains in a pancreatic cell line (PANC-1 cells). ResultsAmong all tested drugs Enviroxime, Fluoxetine, concentrated human IgG product (Hizentra) and Pleconaril were able to eradicate persistent Coxsackievirus B1 infection. The effect Enviroxime, Hizentra and Pleconaril varied between the two virus strains. ConclusionsThe identified drugs are feasible candidates for clinical trials among patients with persistent coxsackievirus B infections or chronic enterovirus-associated diseases.

Assessment of Thymic Output Dynamics After in utero Infection of Mice With Coxsackievirus B4.

The thymus is the main organ of the lymphatic system, in which T cells undergo a rigorous selection to ensure that their receptors (TCRs) will be functional and will not react against the self. Genes encoding for TCR chains are fragmented and must be rearranged by a process of somatic recombination generating TCR rearrangement excision circles (TRECs). We recently documented coxsackievirus B4 (CV-B4) infection of Swiss albino mouse thymus in the course of in utero transmission. In the current study, we intended to evaluate thymic output in this experimental model. For this purpose, pregnant Swiss albino mice were inoculated with CV-B4 at day 10 or 17 of gestation, and thymus and spleen were sampled from offspring at different time points and then subjected to quantification of TREC molecules and Ptk7 gene expression. Results showed a pronounced effect of in utero CV-B4 infection on the thymus with an increase in the cellularity and, consequently, the weight of the organ. sj and DβTREC analysis, by real-time PCR, revealed a significant decrease following CV-B4 infection compared to controls, a decrease which gets worse as time goes by, both in the thymus and in the periphery. Those observations reflect a disturbance in the export of T cells to the periphery and their accumulation within the thymus. The evaluation of Ptk7 transcripts in the thymus, for its part, showed a decrease in expression, especially following an infection at day 10 of gestation, which supports the hypothesis of T cell accumulation in a mature stage in the thymus. The various effects observed correlate either negatively or positively with the viral load in the thymus and spleen. Disruption in thymic export may indeed interfere with T cell maturation. We speculate that this may lead to a premature release of T cells and the possibility of circulating autoreactive or proliferation-impaired T cell clones.

Coxsackievirus B3 Infection of Human Neural Progenitor Cells Results in Distinct Expression Patterns of Innate Immune Genes.

Coxsackievirus B3 (CVB3), a member of Picornaviridae family, is an important human pathogen that causes a wide range of diseases, including myocarditis, pancreatitis, and meningitis. Although CVB3 has been well demonstrated to target murine neural progenitor cells (NPCs), gene expression profiles of CVB3-infected human NPCs (hNPCs) has not been fully explored. To characterize the molecular signatures and complexity of CVB3-mediated host cellular responses in hNPCs, we performed QuantSeq 3′ mRNA sequencing. Increased expression levels of viral RNA sensors (RIG-I, MDA5) and interferon-stimulated genes, such as IFN-β, IP-10, ISG15, OAS1, OAS2, Mx2, were detected in response to CVB3 infection, while IFN-γ expression level was significantly downregulated in hNPCs. Consistent with the gene expression profile, CVB3 infection led to enhanced secretion of inflammatory cytokines and chemokines, such as interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemoattractant protein-1 (MCP-1). Furthermore, we show that type I interferon (IFN) treatment in hNPCs leads to significant attenuation of CVB3 RNA copy numbers, whereas, type II IFN (IFN-γ) treatment enhances CVB3 replication and upregulates suppressor of cytokine signaling 1/3 (SOCS) expression levels. Taken together, our results demonstrate the distinct molecular patterns of cellular responses to CVB3 infection in hNPCs and the pro-viral function of IFN-γ via the modulation of SOCS expression.