Viral Myocarditis Research Articles

Crosstalk Between Innate Immunity and Autophagy in Viral Myocarditis Leading to Dilated Cardiomyopathy.

Viral myocarditis, characterised by inflammation of the heart muscle, presents a significant challenge to global public health, particularly affecting younger individuals and often progressing to dilated cardiomyopathy (DCM), a leading cause of heart failure. Despite ongoing research efforts, viable treatments for this condition remain elusive. Recent studies have shed light on the complex interplay between the innate immune response and autophagy mechanisms, revealing their pivotal roles in the pathogenesis of viral myocarditis and subsequent DCM development. This review aims to delve into the recent advancements in understanding the molecular mechanisms and pathways that intersect innate immunity and autophagy in the context of viral myocarditis. Furthermore, it explores the potential therapeutic implications of these findings, offering insights into promising avenues for the management and treatment of this debilitating condition.

Cardiomyocyte regeneration in human myocarditis

Abstract Background Newly generated cardiomyocytes (NGC) concur to recovery of human myocarditis. Purpose describe NGC’s contribute with age and their modality of myocardial homing and integration. Methods We retrospectively assessed NGC in 213 consecutive patients with endomyocardial biopsy diagnostic for myocarditis, normal coronaries and valves. Tissue samples were processed for histology and immune-histochemistry for CD3+ T lymphocytes, alpha-sarcomeric-actin, junctional connexin-43, Ki-67, phosphorylated STAT3 (p-STAT3) and Western Blot (WB) for HMGB1. Frozen samples were analyzed with polymerase chain reaction (PCR) for cardiotropic viruses. Controls included 20 normal surgical biopsies. NGC were defined as small myocytes (diameter < 10 µ) with nuclear positivity to Ki-67 and p-STAT3, positive immunostaining for cytoplasmic alpha-sarcomeric-actin and connexin 43. Their number/mm2, relation with age and pathway of integration were evaluated. Results PCR was positive for viral genomes in 16% of cases. NGC mean diameter was 6.6 ± 3.34 vs 22.5 ± 3.11 µm adult cells; their number, in comparable LVEF, was 86.3 ± 10.3/mm2 in patients between 10 and 40 years; 50.4 ±13.8/mm2 in those between 41 and 60; 15.1 ± 5.7/ mm2 in those between 61 and 80; control NGC were 0.2± 0.2/mm2 ; NGC were no statistically different in viral and non-viral myocarditis. HMGB1 and STAT-3 were remarkably higher than controls. NGC crossed the membrane and grew integrated within the empty necrotic myocytes. Conclusions NGCs are constantly recognizable in acute human myocarditis. Their number declines with age. Their integration within necrotic myocytes consents preservation of cardiac structure and function.

Effect of extracellular vesicles derived from inflammatory H9C2 cardiomyocytes on the polarization of macrophages and its mechanism

Abstract Objective The aim of this study was to investigate the effect of Extracellular vesicles (EVs) derived from inflammatory cardiomyocytes on the polarization of macrophages and its related mechanism. Methods EVs derived from the inflammatory and normal cardiomyocyte cell line H9C2 were extracted by differential centrifugation respectively. The extracted EVs were characterized by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM) and Western blot analysis (WB). The RAW264.7 macrophages in the inflammatory environment were treated with EVs, the proliferative activities were detected by CCK8, the expression of inflammatory factors were detected by qRT-PCR, and the differentiation of RAW264.7 macrophages into M1 and M2 was analyzed by flow cytometry. In vivo experiments, the animal model of viral myocarditis was established in Balb/c mice with intraperitoneal injection of CVB3. EVs derived from inflammatory H9C2 cardiomyocytes and medium were injected into mice by tail vein injection, respectively. The mice myocardium was stained by immunohistochemistry, and the total RNA of myocardial tissue was extracted for the detection of inflammatory factors by RT-PCR. In terms of mechanism research, mRNA expression profiles of RAW264.7 cells after EVs treatment were analyzed by RNA sequencing for functional annotation and mechanism study. At the same time, the extracted EVs derived from H9C2 normal group and the inflammatory group were subjected to 4D-Lable Free technology for quantitative proteomic analysis, and the results were analyzed bioinformatics, and then by WB analysis.Results We found that EVs derived from inflammatory H9C2 cardiomyocytes decreased the proliferative activity of RAW264.7 macrophages, the expression of pro-inflammatory cytokines IL-6, IL-1β, TNF-ɑ, and the proportion of M1 macrophages in the inflammatory state, while the proportion of M2 macrophages, which mainly inhibit inflammation, increased, and the expression levels of anti-inflammatory cytokines IL-10 and CD-206 increased. Results of immunohistochemical staining and RT-PCR showed that the EVs of inflammatory H9C2 regulated the heterogeneity of infiltrating macrophages and the expression of several inflammatory cytokines in mouse myocardium inflammatory tissue. Meanwhile, in vitro studies have found that the regulatory effect of EVs derived from inflammatory H9C2 cardiomyocytes on macrophage heterogeneity is mediated by MAPK signaling pathway. Conclusion EVs derived from inflammatory H9C2 cardiomyocytes can regulate the polarization of macrophages, change the expression of inflammatory factors, and regulate the myocardial inflammatory microenvironment, which may be achieved by mediating the p38 MAPK pathway through the delivery of PP2A.

Coxsackievirus B3-Induced m6A Modification of RNA Enhances Viral Replication via Suppression of YTHDF-Mediated Stress Granule Formation

N6-methyladenosine (m6A) is the most prevalent internal RNA modification. Here, we demonstrate that coxsackievirus B3 (CVB3), a common causative agent of viral myocarditis, induces m6A modification primarily at the stop codon and 3′ untranslated regions of its genome. As a positive-sense single-stranded RNA virus, CVB3 replicates exclusively in the cytoplasm through a cap-independent translation initiation mechanism. Our study shows that CVB3 modulates the expression and nucleo-cytoplasmic transport of the m6A machinery components—METTL3, ALKBH5 and YTHDFs—resulting in increased m6A modifications that enhance viral replication. Mechanistically, this enhancement is mediated through YTHDF-driven stress granule (SG) formation. We observed that YTHDF proteins co-localize with human antigen R (HuR), a protein facilitating cap-independent translation, in SGs during early infection. Later in infection, YTHDFs are cleaved, suppressing SG formation. Notably, for the first time, we identified that during early infection CVB3’s RNA-dependent RNA polymerase (3D) and double-stranded RNA (dsRNA) are stored in SGs, co-localizing with HuR. This early-stage sequestration likely protects viral components for use in late-phase replication, when SGs are disrupted due to YTHDF cleavage. In summary, our findings reveal that CVB3-induced m6A modifications enhance viral replication by regulating YTHDF-mediated SG dynamics. This study provides a potential therapeutic strategy for CVB3-induced myocarditis.

Efficacy and safety of Shenmai injection in the treatment of viral myocarditis: a systematic review and meta-analysis

PurposeTo evaluate the efficacy and safety of Shenmai injection for the treatment of viral myocarditis (VMS) through systematic evaluation and meta-analysis.MethodsSeven databases were searched to identify randomized controlled trials that examined the use of Shenmai injection for the treatment of VMS. The databases were searched from inception to 20 January 2024. The quality of the included studies was evaluated via the Cochrane risk of bias tool (RoB 2) version 2. Data analysis was performed using Review Manager 5.4 and Stata 16.ResultsIn total, 18 randomized controlled trials were included. The trials were conducted in 2006–2024 and included 1,661 patients with VMS. The results reveal that Shenmai injection combined with conventional treatment was superior to conventional treatment alone in terms of the following outcomes: total effective rate [RR = 1.22, 95% CI (1.16, 1.28)], CKMB [SMD = −3.33, 95% CI (−4.85, −1.81)], electrocardiogram (ECG) efficacy [RR = 1.30, 95% CI (1.20, 1.40)], AST [SMD = -0.70, 95% CI (−1.28, −0.11)], LDH [SMD = −1.17, 95% CI (−1.37, −0.97], p < 0.00001], CK [SMD = −1.74, 95% CI (−2.34, −1.13)], TNF-α [SMD = −1.35, 95% CI (−1.85, −0.84)], and IL-6 [SMD = −1.40, 95% CI (−1.76, −1.05)]. There were no significant differences in the incidence of adverse reactions [RR = 1.56, 95% CI (0.73, 3.33), p = 0.25] or cTnI levels [SMD = −3.35, 95% CI (−6.81, 0.11)] between the groups.ConclusionShenmai injection with conventional treatment can reduce the degree of myocardial injury in patients with VMS, weaken the inflammatory response and improve the clinical efficacy of the conventional treatment. This approach was found to be safe. However, additional high-quality studies are necessary to confirm the reliability of this treatment method.Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/logout.php, identifier PROSPERO (CRD42024518665).

Short- and medium-term longitudinal outcomes of children diagnosed with multisystem inflammatory syndrome in children - report from a single centre in Pakistan.

To determine the short- and medium-term cardiac outcomes in children admitted with multisystem inflammatory syndrome in children at a tertiary care centre in Pakistan. Children fulfilling the criteria for multisystem inflammatory syndrome and admitted to the hospital between April 2020 and March 2022 were enrolled in this prospective longitudinal cohort study. From admission to discharge, laboratory and cardiac parameters were recorded for all patients, who were subsequently followed up in clinics at various intervals. Data analysis was conducted using STATA version 15.0. A total of 51 children were included, with viral myocarditis (41.2%) and toxic shock syndrome (33.3%) being the most common phenotypes. The cardiovascular system was most commonly affected in 27 children (53%) with laboratory evidence of inflammation and myocardial injury with median and interquartile levels of ferritin 1169 (534-1704), C-reactive protein 83 (24-175), lactate dehydrogenase 468 (365-1270), N-terminal pro-B-type natriuretic peptide 8,656 (2,538-31,166), and troponin 0.16 (0.02-2.0).On admission, decreased left ventricular ejection fraction was observed in 58.8% of patients and impaired global longitudinal strain in 33.3%. At discharge, left ventricular ejection fraction had normalised in 83% of patients. Pericardial effusion resolved in all patients, and valvulitis resolved in 86% by 12 months. Paediatric ICU admission was required in 42 (82%) of patients with an overall mortality of 12% (n = 6). Our study finds high hospital mortality for multisystem inflammatory syndrome in children compared to 1-2% from previous studies. Yet, in Pakistan, surviving children with multisystem inflammatory syndrome show favourable short- to medium-term cardiac outcomes.

GIANT CELL MYOCARDITIS: AUTOPSY CONFIRMATION OF A DIAGNOSTIC DILEMMA - A RARE CASE REPORT

Abstract Introduction/Objective Giant cell myocarditis (GCM) is a rare and rapidly progressive form of myocarditis, commonly leading to fulminant heart failure (HF), refractory ventricular arrhythmias or conduction system abnormalities and carrying a high mortality rate without prompt treatment. Due to its rarity, there is limited data on its prevalence, although studies show an incidence of 0.007–0.053% among autopsied cases. This entity primarily affects the heart, exhibiting a rapid clinical course and a poor prognosis necessitating immunosuppressive therapy and, in most instances, heart transplantation to improve survival rates. Methods/Case Report We present a case of a 62-year-old male with a prior history of complete heart block status post permanent pacemaker placement, presenting with acute decompensated heart failure. Laboratory investigations revealed elevated cardiac troponin levels (>35000) with echocardiography showing a reduced ejection fraction of 25% and an initial diagnosis of non-ST elevation myocardial infarction (NSTEMI) was made. Endomyocardial biopsy revealed GCM. Despite aggressive management, including immunosuppressive therapy and mechanical circulatory support, his condition deteriorated rapidly, leading to multiorgan failure and eventual death. The diagnosis was confirmed on autopsy. The diagnostic challenge of GCM lies in its clinical or pathologic overlap with other myocardial disorders such as cardiac sarcoidosis, viral myocarditis, and cardiac amyloidosis. Endomyocardial biopsy (EMB) remains the gold standard for diagnosing this entity which is characterized by a widespread inflammatory cell infiltrate with multinucleated giant cells in association with myocyte damage. The etiology of GCM remains unclear, but it is believed to be immune-mediated, possibly triggered by an autoimmune response. Results (if a Case Study enter NA) NA Conclusion Pathologists should give importance to consider GCM in the differential diagnosis of patients presenting with acute heart failure refractory to standard therapy. Early recognition and prompt initiation of immunosuppressive therapy are crucial for improving outcomes in patients with GCM. Awareness of this entity is crucial to make a timely diagnosis.

The Role of MicroRNA in the Pathophysiology and Diagnosis of Viral Myocarditis

Myocarditis is a non-ischemic condition with a heterogeneous etiology, clinical course and prognosis. The most common etiology of myocarditis are viral infections, whereas the most severe complications are acute and chronic heart failure and sudden cardiac death. The heterogeneous clinical course of the disease, as well as the availability and costs of diagnostic tools such as cardiac magnetic resonance and endomyocardial biopsy, hinder the diagnosis of myocarditis and its underlying cause. Non-coding RNAs such as micro-RNAs (miRNAs; miR) have been shown to be involved in the disease’s pathophysiology; however, their potential in disease diagnosis and treatment should also be considered. Non-coding RNAs are RNAs that are not translated into proteins, and they have the ability to regulate several intracellular pathways. MiRNAs regulate gene expression by binding with their targets and inhibiting protein synthesis by interfering with the translation of coding genes or causing the degradation of messenger RNA. Several miRNAs, such as miR-1, -133, -21, -15, -98, -126, -155, -148, -203, -208, -221, -222, -203 and -590, have been shown to be involved in the pathophysiology of viral myocarditis (VMC), and some of them have been shown to have diagnostic abilities. This article summarizes the available data on miRNAs and their associations with VMC.

Unlocking Toll-Like Receptors: Targeting Therapeutics for Respiratory Tract Infections and Inflammatory Disorders

Abstract: The Toll-like Receptors (TLRs) family has significantly enhanced the understanding of innate immune responses by identifying and responding to various microbes or host-derived organisms. TLRs contribute to these responses by increasing the levels of cytokines, interleukins, and other inflammatory mediators through multiple pathways. Located both intracellularly and on the surface of various cells and tissues, including vascular smooth muscles (VSMs) and myocardium cells, TLRs play distinct roles in innate immune activation, such as recognizing pathogen-associated molecular patterns (PAMPs) and activating downstream signaling pathways. In the context of COVID-19, TLRs are critically involved in the pathophysiology by mediating excessive inflammatory responses that exacerbate disease severity, influencing both the acute phase and long-term outcomes. It has been observed that inflammatory diseases such as atherosclerosis, viral myocarditis, and other comorbidities associated with the spread of COVID-19 have increased, although the exact mechanisms remain not fully understood. Nonetheless, there is evidence of TLR-mediated increased pro-inflammatory signaling by different mechanisms in these diseases. This review explains the role of TLRs in various inflammatory diseases related to COVID-19, including viral myocarditis, acute lung infections, and atherosclerosis. Furthermore, the review discusses various herbal drugs, such as Platycodon grandiflorum, Acanthopanax senticosus, Scutellaria baicalensis Georgi, and Engelhardia roxburghiana, and their mechanisms of action on TLRs, including NF-κB, MyD88-dependent, MyD88-independent pathways, and Plasmacytoid DCs. Enhanced clarity on TLRs' specific contributions to COVID-19 pathophysiology and stronger evidence supporting herbal interventions targeting TLRs could improve the impact and applicability of these findings in clinical settings.

Diagnostic value and clinical significance of lncRNA NEAT1 combined with miR-425-3p in children with viral myocarditis.

Viral myocarditis (VMC) is common in children. Previous studies have reported the clinical value of nuclear paraspeckle assembly transcript 1 (NEAT1) and microRNA-425-3p (miR-425-3p) in certain diseases, but not in VMC. This article was designed to investigate the expression of long noncoding RNA (lncRNA) NEAT1 and miR-425-3p in the serum of patients with VMC and their clinical significance. We assessed VMC and healthy patients and analyzed differences in the expression levels of NEAT1 and miR-425-3p. The correlation and targeting relationship between the two were reported by Spearman correlation analysis and luciferase reporter assay. ROC curves were plotted to reflect the diagnostic effect of both. In addition, according to the 12-month prognostic effect grouping, patients with VMC were separated into a group with good vs. poor prognosis, and the difference in the expression levels of NEAT1 and miR-425-3p between the two groups were analyzed. The ability of the two markers in the prognosis of VMC was further analyzed by multiple logistic regression. NEAT1 expression was up-regulated in VMC and miR-425-3p expression was down-regulated, and there was a negative correlation and targeting link between the two. The diagnostic efficacy of both NEAT1 and miR-425-3p was higher than that of a single indicator. High expression of NEAT1 and low expression of miR-425-3p were found in VMC patients with poor prognosis. Both were independent influencers of VMC prognosis. NEAT1 and miR-425-3p expressions were affected by VMC and had important clinical implications for VMC, indicating for the first time the clinical function of NEAT1 and miR-425-3p in VMC.

LncRNA MALAT1 to Enhance Pyroptosis in Viral Myocarditis Through UPF1-Mediated SIRT6 mRNA Decay and Wnt-β-Catenin Signal Pathway.

Viral myocarditis (VMC) is an inflammatory disease of the myocardium caused by cardioviral infection, especially coxsackievirus B3 (CVB3), and is a major contributor to acute heart failure and sudden cardiac death in children and adolescents. LncRNA MALAT1 knockdown reportedly inhibits the differentiation of Th17 cells to attenuate CVB3-induced VMC in mice. Moreover, long non-coding RNAs (lncRNAs) interact with RNA-binding proteins (RBPs) to regulate UPF1-mediated mRNA decay. However, it remains unclear whether MALAT1 can bind to UPF1 to mediate the mRNA decay of its target genes in VMC. Herein, we aimed to explore the effect of lncRNA MALAT1 on UPF1-mediated SIRT6 mRNA decay in VMC using in vivo and in vitro experiments. CVB3-infected BABL/C mice were used as VMC models, and MALAT1 interfering adenovirus was injected to achieve MALAT1 knockdown. The heart function of the VMC mice was assessed using echocardiography. Pathological changes in myocardial tissues were assessed after hematoxylin-eosin staining. Myocardial injury and inflammation were evaluated by measuring creatine kinase isoenzyme B, cardiac troponin T, interleukin (IL)-1β, and IL-18. TUNEL staining was performed to assess apoptosis in myocardial tissues. In vitro experiments were performed using H9c2 cells after transfection and CVB3 infection. The lactic dehydrogenase release, caspase-1 activity, and IL-1β and IL-18 levels in the cellular supernatant were detected. Western blotting was performed to determine the expression of pyroptosis-related proteins (GSDMD-N, NLRP3, ASC, and Cleaved-Caspase-1) and Wnt/β-catenin signal pathway-related proteins (Wnt1, β-catenin, and p-GSK-3β). RNA immunoprecipitation and RNA stability assays assessed the relationship between MALAT1, UPF1, and SIRT6. CVB3-infected mice and H9c2 cells exhibited elevated MALAT1 and reduced SIRT6 expression. MALAT1 knockdown or SIRT6 overexpression suppressed inflammation and pyroptosis and inhibited the activation of the Wnt/β-catenin signal pathway in myocardial tissues and cells. MALAT1 enhanced the enrichment of SIRT6 mRNA by UPF1 and disturbed the stability of SIRT6 mRNA to promote the development of VMC. MALAT1 can bind UPF1 to mediate SIRT6 mRNA decay and activate the Wnt/β-catenin signal pathway in VMC.

Chromosome-Level Genome Assembly for the Chinese Serow (Capricornis milneedwardsii) Provides Insights Into Its Taxonomic Status and Evolution.

Chinese serow (Capricornis milneedwardsii) is mainly distributed in the south of Yellow River in China, which has been listed as vulnerable by the International Union for Conservation of Nature (IUCN). However, the reference genome of serow has not been reported and its taxonomic status is still unclear. Here, we first constructed a high-quality chromosome-level reference genome of C. milneedwardsii using PacBio long HiFi reads combined with Hi-C technology. The assembled genome was ~2.83 Gb in size, with a contig N50 of 100.96 Mb and scaffold N50 of 112.75 Mb, which were anchored onto 24 chromosomes. Furthermore, we found that the Chinese serow was more closely related to muskox, which diverged from ~4.85 million years ago (Mya). Compared to the karyotype of goat (2n = 60), we found the Chinese serow (2n = 48) experienced six chromosome fusions, which resulted in the formation of six central centromere chromosomes. We also identified two positively selected genes (MYH6 and DCSTAMP) specific to Chinese serow, which were involved in 'viral myocarditis' and 'Cardiac muscle contraction'. Interestingly, compared to other Caprinae animals, the MYH6 protein of Chinese serow occurred two mutations (E1520S and G1521S), which might be related to hypoxia tolerance. The high-quality reference genome of C. milneedwardsii provides a valuable information for protection of serows and insights into its evolution.

Maternal Exposure to Polystyrene Nanoplastics Induces Sex-Specific Cardiotoxicity in Offspring Mice

Globally, plastic pollution threatens human health, particularly affecting the hearts of offspring exposed to maternal environmental factors early in development. Few studies have specifically addressed sex-specific cardiac injury in offspring resulting from maternal exposure to polystyrene nanoplastics (PS-NPs). This study investigates the potential cardiac injury in offspring following maternal exposure to 1 mg/L PS-NPs. Pregnant C57BL/6J mice were exposed to PS-NPs until 3 weeks postpartum to establish a maternal exposure model. Heart tissues were collected and weighed, and the transcriptomes of the offspring hearts were sequenced and analyzed using high-throughput RNA sequencing. Immunohistochemical staining was performed to assess the effects of PS-NPs on cardiac immune infiltration, fibrosis, and apoptosis in the offspring. PS-NPs caused a significant reduction in heart and body weight in female offspring compared to males. Additionally, PS-NPs induced sex-specific transcriptional reprogramming and metabolic disruptions in the offspring. PS-NPs also induced significant fibrosis, apoptosis, and increased CD68+ macrophage infiltration in offspring hearts. Notably, PS-NPs induced distinct cardiovascular diseases in the offspring. Fluid shear stress and atherosclerosis were significantly enriched in PS-NP-treated male offspring, while viral myocarditis was predominantly enriched in PS-NP-treated females. Our findings suggest that PS-NPs induce cardiotoxicity in offspring by disrupting metabolism, impairing immunity, and triggering fibrosis and apoptosis, with sex-specific differences. This study provides novel insights and a foundation for understanding sex-specific pharmacological differences and interventions in PS-NP-induced cardiovascular disease in offspring.

TRIM56 restricts Coxsackievirus B infection by mediating the ubiquitination of viral RNA-dependent RNA polymerase 3D.

Coxsackievirus B (CVB) is the major causative pathogen for severe diseases such as viral myocarditis, meningitis, and pancreatitis. There is no effective antiviral therapy currently available for CVB infection primarily due to that the pathogenesis of CVB has not been completely understood. Viruses are obligate intracellular pathogens which subvert cellular processes to ensure viral replication. Dysregulation of ubiquitination has been implicated in CVB infection. However, how ubiquitination is involved in CVB infection remains unclear. Here we found that the 3D protein of CVB3, the RNA-dependent RNA polymerase, was modified at K220 by K48-linked polyubiquitination which promoted its degradation through proteasome. Proteomic analysis showed that the E3 ligase TRIM56 was upregulated in CVB3-infected cells, while the majority of TRIMs remained unchanged. Pull-down and immunoprecipitation analyses showed that TRIM56 interacted with CVB3 3D. Immunofluorescence observation showed that viral 3D protein was colocalized with TRIM56. TRIM56 overexpression resulted in enhanced ubiquitination of CVB3 3D and decreased virus yield. Moreover, TRIM56 was cleaved by viral 3C protease in CVB3-infected cells. Taken together, this study demonstrated that TRIM56 mediates the ubiquitination and proteasomal degradation of the CVB3 3D protein. These findings demonstrate that TRIM56 is an intrinsic cellular restriction factor against CVB infection, and enhancing viral protein degradation could be a potential strategy to control CVB infection.

Coxsackievirus group B3 regulates ASS1-mediated metabolic reprogramming and promotes macrophage inflammatory polarization in viral myocarditis.

Viral myocarditis (VMC) is a common and potentially life-threatening myocardial inflammatory disease, most commonly caused by CVB3 infection. So far, the pathogenesis of VMC caused by CVB3 is mainly focused on two aspects: one is the direct myocardial injury caused by a large number of viral replication in the early stage of infection, and the other is the local immune cell infiltration and inflammatory damage of the myocardium in the adaptive immune response stage. There are few studies on the early innate immunity of CVB3 infection in myocardial tissue, but the appearance of macrophages in the early stage of CVB3 infection suggests that they can play a regulatory role as early innate immune response cells in myocardial tissue. Here, we discovered a possible new mechanism of VMC caused by CVB3, revealed new drug targets for anti-CVB3, and discovered the therapeutic potential of citrulline for VMC.

Coxsackievirus B3 Activates Macrophages Independently of CAR-Mediated Viral Entry.

Enteroviruses are a genus of small RNA viruses that are responsible for approximately one billion global infections annually. These infections range in severity from the common cold and flu-like symptoms to more severe diseases, such as viral myocarditis, pancreatitis, and neurological disorders, that continue to pose a global health challenge with limited therapeutic strategies currently available. In the current study, we sought to understand the interaction between coxsackievirus B3 (CVB3), which is a model enterovirus, and macrophage cells, as there is limited understanding of how this virus interacts with macrophage innate immune cells. Our study demonstrated that CVB3 can robustly activate macrophages without apparent viral replication in these cells. We also showed that myeloid cells lacked the viral entry receptor coxsackievirus and adenovirus receptor (CAR). However, the expression of exogenous CAR in RAW264.7 macrophages was unable to overcome the viral replication deficit. Interestingly, the CAR expression was associated with altered inflammatory responses during prolonged infection. Additionally, we identified the autophagy protein LC3 as a novel stimulus for macrophage activation. These findings provide new insights into the mechanisms of CVB3-induced macrophage activation and its implications for viral pathogenesis.

Receptors and Host Factors for Enterovirus Infection: Implications for Cancer Therapy.

Enteroviruses, with their diverse clinical manifestations ranging from mild or asymptomatic infections to severe diseases such as poliomyelitis and viral myocarditis, present a public health threat. However, they can also be used as oncolytic agents. This review shows the intricate relationship between enteroviruses and host cell factors. Enteroviruses utilize specific receptors and coreceptors for cell entry that are critical for infection and subsequent viral replication. These receptors, many of which are glycoproteins, facilitate virus binding, capsid destabilization, and internalization into cells, and their expression defines virus tropism towards various types of cells. Since enteroviruses can exploit different receptors, they have high oncolytic potential for personalized cancer therapy, as exemplified by the antitumor activity of certain enterovirus strains including the bioselected non-pathogenic Echovirus type 7/Rigvir, approved for melanoma treatment. Dissecting the roles of individual receptors in the entry of enteroviruses can provide valuable insights into their potential in cancer therapy. This review discusses the application of gene-targeting techniques such as CRISPR/Cas9 technology to investigate the impact of the loss of a particular receptor on the attachment of the virus and its subsequent internalization. It also summarizes the data on their expression in various types of cancer. By understanding how enteroviruses interact with specific cellular receptors, researchers can develop more effective regimens of treatment, offering hope for more targeted and efficient therapeutic strategies.

N6-Methyladenosine Positively Regulates Coxsackievirus B3 Replication.

Enteroviruses such as coxsackievirus B3 are identified as a common cause of viral myocarditis, but the potential mechanism of its replication and pathogenesis are largely unknown. The genomes of a variety of viruses contain N6-methyladenosine (m6A), which plays important roles in virus replication. Here, by using the online bioinformatics tools SRAMP and indirect immunofluorescence assay (IFA), we predict that the CVB3 genome contains m6A sites and found that CVB3 infection could alter the expression and cellular localization of m6A-related proteins. Moreover, we found that 3-deazaadenosine (3-DAA), an m6A modification inhibitor, significantly decreased CVB3 replication. We also observed that the m6A methyltransferases methyltransferase-like protein 3 (METTL3) and METTL14 play positive roles in CVB3 replication, whereas m6A demethylases fat mass and obesity-associated protein (FTO) or AlkB homolog 5 (ALKBH5) have opposite effects. Knockdown of the m6A binding proteins YTH domain family protein 1 (YTHDF1), YTHDF2 and YTHDF3 strikingly decreased CVB3 replication. Finally, the m6A site mutation in the CVB3 genome decreased the replication of CVB3 compared with that in the CVB3 wild-type (WT) strain. Taken together, our results demonstrated that CVB3 could exploit m6A modification to promote viral replication, which provides new insights into the mechanism of the interaction between CVB3 and the host.

Discovery of Natural Multi‐Target Neuraminidase Inhibitors Anti‐Influenza Virus from Chinese Medicinal Herbs Containing Coumarin: In Silico and In Vitro Experiments

AbstractDuring in silico research, based on molecular docking, dynamics simulation, network pharmacology and ADMET (absorption, distribution, metabolism, excretion, and toxicity) property, 31 potential compounds are obtained from seven Chinese medicinal herbs containing coumarins. Moreover, mechanism researches discover these compounds treat influenza A virus through key targets TLR4, MMP9, and IL6 (high fever, acute respiratory distress syndrome), MAPK1 and MAPK3 (MAPK signaling pathway, viral RNP export and viral protein expression), CASP3 (apoptosis), EP300 and CREBBP (viral myocarditis, chemoattraction of monocytes and macrophages, T cell activation antibody response). Further experimental verification finds that 22 of 31 compounds have various degrees of anti‐influenza virus activities. Moreover, 12 of 22 compounds have better biological activities (IC50=0.1609–54.95 μM) than oseltamivir (IC50=114.3 μM). 3 of 12 compounds have better antioxidant activities (IC50=2.087–3.796 μM) than vitamin C (IC50=5.004 μM). Therefore, ellagic acid, hyperoside, and fraxetin are promising multi‐target lead compounds for influenza virus therapy. Meanwhile, the present study offers compelling evidence for the development of novel antiviral medications.

Lymphocytic Myocarditis in Children with Parvovirus B19 Infection: Pathological and Molecular Insights

Background: This study aims to evaluate the role of parvovirus B19 (B19V) in the pathogenesis of myocarditis in a paediatric population, including post-mortem samples from two children. Methods: From 2004 to 2023, endomyocardial biopsies (EMBs) from children under 16 years of age were analyzed using histology, immunohistochemistry, and molecular pathology. A total of 306 children with acute and 1060 children with chronic lymphocytic myocarditis were identified. Results: B19V infection was more frequent in acute myocarditis than in chronic myocarditis (43% vs. 14%), with higher viral loads in acute cases regardless of age. The most prominent cardiac CD3+ T cell infiltration was noted in children < 2 years, correlating with high cardiac B19V loads. In two male infants who died from B19V infection, B19V DNA was localized in the endothelial cells of multiple organs using in situ hybridization. Virus replication was found in the endothelial cells of small cardiac arterioles and venules but not in capillaries. B19V DNA/mRNA was also detected in immune cells, especially in the spleen and lymph nodes, revealing virus replication in B lymphocytes. Conclusions: B19V can induce severe lymphocytic myocarditis, especially in young children. The simultaneous histopathological and molecular assessment of EMBs is important for early diagnosis of viral myocarditis, preventing severe disease, and ensuring appropriate therapy.