CVB3-induced Myocarditis Research Articles

Icariin ameliorates Coxsackievirus B3-induced viral myocarditis by modulating the S100 calcium binding protein A6/β-catenin/c-Myc signaling pathway

BackgroundCoxsackievirus B3 (CVB3) is a leading cause of viral myocarditis and is currently lacking specific pharmacological treatments, highlighting the critical need for therapeutic development. Icariin (ICA), a prenylated flavonol glycoside, was previously found to exhibit several pharmacological effects, but its potential to combat CVB3 remains uninvestigated. PurposeThis study aimed to elucidate the anti-CVB3 efficacy of ICA and elucidate its molecular mechanisms. MethodsCVB3-infected HeLa cells, H9C2 cells and neonate rat ventricular cardiomyocytes (NRVCs) were selected as in vitro models, and were treated with ICA at 1 and 10 μM. Additionally, BALB/c mice that were infected with CVB3 via intraperitoneal injection were chosen as in vivo model and were treated with ICA or ribavirin over 3 days. The effect of ICA against CVB3 was determined by Cell Counting Kit-8 (CCK-8) assay, western blot, real-time fluorescence quantitative PCR (RT–qPCR), terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC) and flow cytometry. ResultsIn this study, it was found that ICA is capable of reducing CVB3 viral load both in vitro and in vivo. Mechanistic studies suggested that ICA prevents cardiomyocyte apoptosis by attenuating the S100 calcium binding protein A6 (S100A6)/β-catenin/c-Myc signaling pathway. Additionally, ICA inhibits the secretion of proinflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β) and CXC motif chemokine ligand 2 (CXCL2) in heart tissue, thereby mitigating CVB3-induced myocarditis. Moreover, ICA also regulates the immune response of CD4+ T, CD8+ T and Treg cells by changing the cells numbers in spleen tissue. Lastly, ICA can reduce the load of other enteroviruses (such as CVA6, CVA16 and EV71) in rhabdomyosarcoma (RD) cells as well. ConclusionOur findings indicate that ICA provides significant protection against CVB3 infection by modulating the S100A6/β-catenin/c-Myc signaling pathway, suggesting its potential use as a novel drug against CVB3 infection in clinical application.

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.

Sex Differences in Expression of Pro-Inflammatory Markers and miRNAs in a Mouse Model of CVB3 Myocarditis.

Myocarditis is an inflammatory disease that may lead to dilated cardiomyopathy. Viral infection of the myocardium triggers immune responses, which involve, among others, macrophage infiltration, oxidative stress, expression of pro-inflammatory cytokines, and microRNAs (miRNAs). The cardioprotective role of estrogen in myocarditis is well documented; however, sex differences in the miRNA expression in chronic myocarditis are still poorly understood, and studying them further was the aim of the present study. Male and female ABY/SnJ mice were infected with CVB3. Twenty-eight days later, cardiac tissue from both infected and control mice was used for real-time PCR and Western blot analysis. NFκB, IL-6, iNOS, TNF-α, IL-1β, MCP-1, c-fos, and osteopontin (OPN) were used to examine the inflammatory state in the heart. Furthermore, the expression of several inflammation- and remodeling-related miRNAs was analyzed. NFκB, IL-6, TNF-α, IL-1β, iNOS, and MCP-1 were significantly upregulated in male mice with CVB3-induced chronic myocarditis, whereas OPN mRNA expression was increased only in females. Further analysis revealed downregulation of some anti-inflammatory miRNA in male hearts (let7a), with upregulation in female hearts (let7b). In addition, dysregulation of remodeling-related miRNAs (miR27b and mir199a) in a sex-dependent manner was observed. Taken together, the results of the present study suggest a sex-specific expression of pro-inflammatory markers as well as inflammation- and remodeling-related miRNAs, with a higher pro-inflammatory response in male CVB3 myocarditis mice.

Investigating TIP30-Mediated regulation of mTORC1 signaling as a therapeutic strategy for coxsackievirus B3-Induced viral myocarditis

This study aims to elucidate the role of TIP30 (30 KDa HIV-1 TAT-Interacting Protein) in the progression of coxsackievirus B3 (CVB3)-induced viral myocarditis. TIP30 knockout and wildtype mice were intraperitoneally infected with CVB3 and evaluated at day 7 post-infection. HeLa cells were transfected with TIP30 lentiviral particles and subsequently infected with CVB3 to evaluate viral replication, cellular pathogenesis, and mechanistic target of rapamycin complex 1 (mTORC1) signaling. Deletion of the TIP30 gene heightened heart virus titers and mortality rates in mice with CVB3-induced myocarditis, exacerbating cardiac damage and fibrosis, and elevating pro-inflammatory factors level. In vitro experiments demonstrated the modulation of mTORC1 signaling by TIP30 during CVB3 infection in HeLa cells. TIP30 overexpression mitigated CVB3-induced cellular pathogenesis and VP1 expression, with rapamycin, an mTOR1 inhibitor, reversing these effects. These findings suggest TIP30 plays a critical protective role against CVB3-induced myocarditis by regulating mTORC1 signaling.

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.

MiR-29b-3p regulates cardiomyocytes pyroptosis in CVB3-induced myocarditis through targeting DNMT3A.

Viral myocarditis (VMC) is a disease resulting from viral infection, which manifests as inflammation of myocardial cells. Until now, the treatment of VMC is still a great challenge for clinicians. Increasing studies indicate the participation of miR-29b-3p in various diseases. According to the transcriptome sequencing analysis, miR-29b-3p was markedly upregulated in the viral myocarditis model. The purpose of this study was to investigate the role of miR-29b-3p in the progression of VMC. We used CVB3 to induce primary cardiomyocytes and mice to establish a model of viral myocarditis. The purity of primary cardiomyocytes was identified by immunofluorescence. The cardiac function of mice was detected by Vevo770 imaging system. The area of inflammatory infiltration in heart tissue was shown by hematoxylin and eosin (H&E) staining. The expression of miR-29b-3p and DNMT3A was detected by quantitative real time polymerase chain reaction (qRT-PCR). The expression of a series of pyroptosis-related proteins was detected by western blot. The role of miR-29b-3p/DNMT3A in CVB3-induced pyroptosis of cardiomyocytes was studied in this research. Our data showed that the expression of miR-29b-3p was upregulated in CVB3-induced cardiomyocytes and heart tissues in mice. To explore the function of miR-29b-3p in CVB3-induced VMC, we conducted in vivo experiments by knocking down the expression of miR-29b-3p using antagomir. We then assessed the effects on mice body weight, histopathology changes, myocardial function, and cell pyroptosis in heart tissues. Additionally, we performed gain/loss-of-function experiments in vitro to measure the levels of pyroptosis in primary cardiomyocytes. Through bioinformatic analysis, we identified DNA methyltransferases 3A (DNMT3A) as a potential target gene of miR-29b-3p. Furthermore, we found that the expression of DNMT3A can be modulated by miR-29b-3p during CVB3 infection. Our results demonstrate a correlation between the expression of DNMT3A and CVB3-induced pyroptosis in cardiomyocytes. These findings unveil a previously unidentified mechanism by which CVB3 induces cardiac injury through the regulation of miR-29b-3p/DNMT3A-mediated pyroptosis.

Retraction Note to: A New Co(II)-Containing Coordination Polymer Constructed by the Mixed-Ligand Approach: Crystal Structure and Alleviation of CVB3-Induced Myocarditis by Inhibiting Inflammatory Cytokines Production

Retraction Note to: A New Co(II)-Containing Coordination Polymer Constructed by the Mixed-Ligand Approach: Crystal Structure and Alleviation of CVB3-Induced Myocarditis by Inhibiting Inflammatory Cytokines Production

M2 macrophage exosome-derived lncRNA AK083884 protects mice from CVB3-induced viral myocarditis through regulating PKM2/HIF-1α axis mediated metabolic reprogramming of macrophages

Viral myocarditis (VM) is a clinically common inflammatory disease. Accumulating literature has indicated that M2 macrophages protect mice from Coxsackievirus B3 (CVB3)-induced VM. However, mechanisms that underlie M2 macrophages alleviating myocardial inflammation remain largely undefined. We found that M2 macrophage-derived exosomes (M2-Exo) can effectively attenuate VM. The long non-coding RNA (lncRNA) AK083884 in M2-Exo was found to be involved in the regulation of macrophage polarization by exosome lncRNA sequencing combined with in vitro functional assays. M2-Exo-derived AK083884 promotes macrophage M2 polarization and protects mice from CVB3-induced VM. Furthermore, we identified pyruvate kinase M2 (PKM2) as a protein target binding to AK083884 and found that PKM2 knockdown could promote macrophages to polarize to M2 phenotype. Intriguingly, functional assay revealed that downregulation of AK083884 promotes metabolic reprogramming in macrophages. In addition, co-immunoprecipitation was performed to reveal AK083884 could interact with PKM2 and inhibition of AK083884 can facilitate the binding of PKM2 and HIF-1α. Collectively, our findings uncovered an important role of M2-Exo-derived AK083884 in the regulation of macrophage polarization through metabolic reprogramming, identified a new participant in the development of VM and provided a potential clinically important therapeutic target.

Abstract 16000: β-arrestins Mediate Cardiac Infiltration of Cytotoxic CD8+ T Cells and Macrophages in Acute CVB3 Viral Myocarditis

Introduction: In response to Coxsackievirus B3 (CVB3) infection, immune cells infiltrate the heart affecting viral clearance, tissue damage, and cardiac remodeling. However, the molecular mechanisms regulating the immune response during acute CVB3-induced myocarditis are not well understood. β arrestins (βarrs), scaffolding proteins that mediate G protein-coupled receptor internalization, desensitization, and signaling are known to regulate immune responses. Hypothesis: We hypothesized that the immune populations infiltrating the heart during acute CVB3 infection are dependent on βarrs. Methods: To test our hypothesis, 5- to 7-week-old mice lacking βarr1 (βarr1 KO; n=8), βarr2 (βarr2 KO; n=4), or C57BL/6 controls (WT; n=7) were injected intraperitoneally with 1x10 4 plaque forming units (PFU) of CVB3 or saline and immune cell populations were measured in the heart at 7 days post infection (dpi) using flow cytometry. Results: At 7 dpi, there was a marked increase in cytotoxic CD8+ T cells in hearts of WT mice that positively correlated with the level of viral infection as assessed by heart tissue PFU (slope= 1.34, Y-intercept= -3.77). In contrast, the degree of infiltration of CD8+ T cells was significantly blunted in βarr KO hearts over a broad range of heart PFU (βarr1 KO: Slope=-0.3, Y-intercept=1.65; p=0.03 vs WT; βarr2 KO: Slope=-0.32, Y-intercept= 1.3; p=0.003 vs WT). Helper CD4+ T cell populations remained unaltered at 7 dpi among all groups. Macrophages at 7 dpi were significantly reduced in βarr KO hearts over a range of PFU (WT: Slope= 18.6, Y-intercept -52.32; βarr1 KO: Slope= -5, Y-intercept=32; βarr2 KO: Slope=3.46, Y-intercept=-8.4; p=0.04 vs WT). To assess cardiac injury, we measured the level of apoptosis by TUNEL staining and found that CVB3 infected βarr KO hearts showed significantly fewer TUNEL positive cells than WT CVB3 infected controls (WT 8.7%± 2.74; βarr1 KO 1.7%±0.51; βarr2 KO 1.7%±0.37; p=0.04 vs. WT). Conclusions: These data indicate that βarrs participate in the cardiac infiltration of CD8+ T cells and macrophages in response to CVB3 infection and that blocking the action of βarrs may diminish the cardiotoxicity with the acute phase of CVB3-induced myocarditis.

Cytoplasm Hydrogelation-Mediated Cardiomyocyte Sponge Alleviated Coxsackievirus B3 Infection.

Viral myocarditis (VMC), commonly caused by coxsackievirus B3 (CVB3) infection, lacks specific treatments and leads to serious heart conditions. Current treatments, such as IFNα and ribavirin, show limited effectiveness. Herein, rather than inhibiting virus replication, this study introduces a novel cardiomyocyte sponge, intracellular gelated cardiomyocytes (GCs), to trap and neutralize CVB3 via a receptor-ligand interaction, such as CAR and CD55. By maintaining cellular morphology, GCs serve as sponges for CVB3, inhibiting infection. In vitro results revealed that GCs could inhibit CVB3 infection on HeLa cells. In vivo, GCs exhibited a strong immune escape ability and effectively inhibited CVB3-induced viral myocarditis with a high safety profile. The most significant implication of this study is to develop a universal antivirus infection strategy via intracellular gelation of the host cell, which can be employed not only for treating defined pathogenic viruses but also for a rapid response to infection outbreaks caused by mutable and unknown viruses.

Ruxolitinib ameliorated coxsackievirus B3-induced acute viral myocarditis by suppressing the JAK-STAT pathway

BackgroundAccumulating evidences have demonstrated that overwhelming inflammation occurs in the process of Coxsackievirus B3 (CVB3)-induced acute viral myocarditis (AVM). No specific therapy is available. More than an effective Janus-associated kinase (JAK) inhibiter, ruxolitinib exerts a critical role in the inflammatory diseases. In this study, we investigated the potential effect of ruxolitinib on CVB3-induced acute viral myocarditis. MethodIn vivo, BALB/c mice were intraperitoneally injected of CVB3, treated of a successive gavage of ruxolitinib for seven days, and subjected to a series of analysis. In vitro, primary bone marrow-derived macrophages (BMDMs) and cardiac fibroblasts were isolated, cultured, treated, harvested and finally detected. ResultsIn vivo, acute viral myocarditis was successfully induced by the injection of CVB3 characterized by impaired cardiac function, predominant infiltration of inflammatory cells, necroptosis of myocardium, great increase of cardiac troponin I (cTnI) and cytokine levels, replication of CVB3, and excessive activation of JAK-STAT pathways. Oral administration of ruxolitinib suppressed the activation of JAK-STAT pathway in a dosage-dependent way, lessened the infiltration of inflammatory cells and necroptosis of myocardium, reduced the levels of cTnI and cytokines, and finally alleviated CVB3-induced cardiac dysfunction, with the reduced production of type I interferon and no promising effect on the replication of CVB3. In vitro, the treatment of ruxolitinib inhibited the activation of JAK-STAT pathway and increase of multiple cytokines mRNA levels in BMDMs and had no protective effect against CVB3 replication in cardiac fibroblasts. ConclusionsOur study suggested that ruxolitinib ameliorated CVB3-induced AVM by inhibiting the activation of JAK-STAT pathway, infiltration of inflammatory cells and necroptosis of myocardium, which may provide a novel strategy for AVM therapy.

Cardiac miR-19a/19b was induced and hijacked by CVB3 to facilitate virus replication via targeting viral genomic RdRp-encoding region

Coxsackievirus B3 (CVB3) is one of the major pathogens of viral myocarditis, lacking specific anti-virus therapeutic options. Increasing evidence has shown an important involvement of the miR-17-92 cluster both in virus infection and cardiovascular development and diseases, while its role in CVB3-induced viral myocarditis remains unclear. In this study, we found that miR-19a and miR-19b were significantly up-regulated in heart tissues of CVB3-infected mice and exerted a significant facilitatory impact on CVB3 biosynthesis and replication, with a more pronounced effect observed in miR-19b, by targeting the encoding region of viral RNA-dependent RNA polymerase 3D (RdRp, 3Dpol) to increase viral genomic RNA stability. The virus-promoting effects were nullified by the synonymous mutations in the viral 3Dpol-encoding region, which corresponded to the seed sequence shared by miR-19a and miR-19b. In parallel, treatment with miR-19b antagomir not only resulted in a noteworthy suppression of CVB3 replication and infection in infected cells, but also demonstrated a significant reduction in the cardiac viral load of CVB3-infected mice, resulting in a considerable alleviation of myocarditis. Collectively, our study showed that CVB3-induced cardiac miR-19a/19b contributed to viral myocarditis via facilitating virus biosynthesis and replication, and targeting miR-19a/19b might represent a novel therapeutic target for CVB3-induced viral myocarditis.

Critical roles of parkin and PINK1 in coxsackievirus B3-induced viral myocarditis

Viral myocarditis is an inflammatory disease of the myocardium, often leads to cardiac dysfunction and death. PARKIN (PRKN) and PINK1, well known as Parkinson's disease-associated genes, have been reported to be involved in innate immunity and mitochondrial damage control. Therefore, we investigated the role of parkin and PINK1 in coxsackievirus B3 (CVB3)-induced viral myocarditis because the etiology of myocarditis is related to abnormal immune response to viral infection and mitochondrial damage. After viral infection, the survival was significantly lower and myocardial damage was more severe in parkin knockout (KO) and PINK1 KO mice compared to wild-type (WT) mice. Parkin KO and PINK1 KO showed defective immune cell recruitment and impaired production of antiviral cytokines such as interferon-gamma, allowing increased viral replication. In addition, parkin KO and PINK1 KO mice were more susceptible to CVB3-induced mitochondrial damage than WT mice, resulting in susceptibility to viral-induced cardiac damage. Finally, using publicly available RNA-seq data, we found that pathogenic mutants of the PRKN gene are more common in patients with dilated cardiomyopathy and myocarditis than in controls or the general population. This study will help elucidate the molecular mechanism of CVB3-induced viral myocarditis.

Abstract P3083: Trim29 Deficiency Ameliorates Viral Myocarditis By Reducing Perk Mediated Er Stress And Ros Responses

Infections by viruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could cause viral myocarditis. Endoplasmic reticulum (ER) stress is associated with several metabolic diseases such as cardiovascular disease, diabetes and cancer. However, the immune mechanisms of ER stress regulation in controlling the pathogenesis of viral myocarditis are unclear. Here, we found that knockdown or knockout of TRIM29 significantly inhibited PERK (Protein kinase RNA-like endoplasmic reticulum kinase) mediated ER stress and apoptosis induced by cardiotropic viruses CVB3 (coxsackievirus B3) or EMCV (encephalomyocarditis virus) in human and mouse cardiomyocytes. Additionally, TRIM29 deficiency relieved ROS (Reactive oxygen species) mediated STING (Stimulator of interferon genes) inhibition to produce more type I interferon for restricting cardiotropic viruses in cardiomyocytes. Importantly, cardiomyocytes specific TRIM29 deficiency exhibited dramatic protective effects on cardiac damage, cardiac dysfunction, viral replication and promoted survival in CVB3-induced viral myocarditis model in vivo . Mechanistically, TRIM29 was shown to interact with PERK and catalyze SUMOylation for maintaining its stability, thereby promoting PERK mediated ER stress and ROS responses to induce pathogenesis of viral myocarditis. Our results indicate that TRIM29 loss-of-function in cardiomyocytes ameliorates viral myocarditis by reducing PERK mediated ER stress response and unleashing ROS-suppressed interferon response. Our data suggest the TRIM29-PERK axis is a potential therapeutic target for viral myocarditis and other ER stress-associated cardiovascular disease.

Statement of Retraction: A new Co(II)-bearing coordination polymer: structural characterization and treatment effect on CVB3-induced myocarditis via suppressing inflammatory response

Statement of Retraction: A new Co(II)-bearing coordination polymer: structural characterization and treatment effect on CVB3-induced myocarditis via suppressing inflammatory response

Cardiomyocyte-derived HMGB1 takes a protective role in CVB3-induced viral myocarditis via inhibiting cardiac apoptosis.

Coxsackievirus B3 (CVB3)-induced viral myocarditis (VMC) is characterized by immune cell infiltration and myocardial damage. High mobility group box 1 (HMGB1) is a highly conserved nuclear DNA-binding protein that participates in DNA replication, transcriptional regulation, repair response and inflammatory response in different disease models. To investigate the exact function of HMGB1 in CVB3-induced VMC, we crossed Hmgb1-floxed (Hmgb1f/f ) mice with mice carrying a suitable Cre recombinase transgenic strain to achieve conditional inactivation of the Hmgb1 gene in a cardiomyocyte-specific manner and to establish myocarditis. In this study, we found that cardiomyocyte-specific Hmgb1-deficient (Hmgb1f/f TgCre/+ ) mice exhibited exacerbated myocardial injury.Hmgb1-deficient cardiomyocytes may promote early apoptosis via the p53-mediated Bax mitochondrial pathway, as evidenced by the higher localization of p53 protein in the cytosol of Hmgb1-deficient cardiomyocytes upon CVB3 infection. Moreover, cardiomyocyte Hmgb1-deficient mice are more susceptible to cardiac dysfunction after infection. This study provides new insights into HMGB1 in VMC pathogenesis and a strategy for appropriate blocking of HMGB1 in the clinical treatment of VMC.

Alterations of the gut microbiome and metabolic profile in CVB3-induced mice acute viral myocarditis

BackgroundAcute viral myocarditis (AVMC) is an inflammatory disease of the myocardium. Evidence indicates that dysbiosis of gut microbiome and related metabolites intimately associated with cardiovascular diseases through the gut-heart axis.MethodsWe built mouse models of AVMC, then applied 16 S rDNA gene sequencing and UPLC-MS/MS metabolomics to explore variations of gut microbiome and disturbances of cardiac metabolic profiles.ResultsCompared with Control group, analysis of gut microbiota showed lower diversity in AVMC, decreased relative abundance of genera mainly belonging to the phyla Bacteroidetes, and increased of phyla Proteobacteria. Metabolomics analysis showed disturbances of cardiac metabolomics, including 62 increased and 84 decreased metabolites, and mainly assigned to lipid, amino acid, carbohydrate and nucleotide metabolism. The steroid hormone biosynthesis, cortisol synthesis and secretion pathway were particularly enriched in AVMC. Among them, such as estrone 3-sulfate, desoxycortone positively correlated with disturbed gut microbiome.ConclusionIn summary, both the structure of the gut microbiome community and the cardiac metabolome were significantly changed in AVMC. Our findings suggest that gut microbiome may participate in the development of AVMC, the mechanism may be related to its role in dysregulated metabolites such as steroid hormone biosynthesis.

Inhibitor of CD147 Suppresses T Cell Activation and Recruitment in CVB3-Induced Acute Viral Myocarditis.

Viral myocarditis (VMC) is a common disease characterized by cardiac inflammation. AC-73, an inhibitor of CD147, disrupts the dimerization of CD147, which participates in the regulation of inflammation. To explore whether AC-73 could alleviate cardiac inflammation induced by CVB3, mice were injected intraperitoneally with AC-73 on the fourth day post-infection (dpi) and sacrificed on the seventh dpi. Pathological changes in the myocardium, T cell activation or differentiation, and expression of cytokines were analyzed using H&E staining, flow cytometry, fluorescence staining and multiplex immunoassay. The results showed that AC-73 alleviated cardiac pathological injury and downregulated the percentage of CD45+CD3+ T cells in the CVB3-infected mice. The administration of AC-73 reduced the percentage of activated CD4+ and CD8+ T cells (CD69+ and/or CD38+) in the spleen, while the percentage of CD4+ T cell subsets in the spleen was not changed in the CVB3-infected mice. In addition, the infiltration of activated T cells (CD69+) and macrophages (F4/80+) in the myocardium also decreased after the AC-73 treatment. The results also showed that AC-73 inhibited the release of many cytokines and chemokines in the plasma of the CVB3-infected mice. In conclusion, AC-73 mitigated CVB3-induced myocarditis by inhibiting the activation of T cells and the recruitment of immune cells to the heart. Thus, CD147 may be a therapeutic target for virus-induced cardiac inflammation.

B-arrestin deletion abrogates the innate immune response in murine CVB3 myocarditis

β-arrestins (βarrs), initially discovered as desensitizers of GPCR signaling, are now known to function as intracellular scaffolds and signaling transducers mediating a wide array of signaling cascades including immune responses to inflammatory stimuli. An important cause of immune cell infiltration and cardiac inflammation are viral pathogens such as enterovirus coxsackievirus B3 (CVB3) induced myocarditis. While viral myocarditis is a leading cause of dilated cardiomyopathy, the precise molecular mechanisms for the acute immune response to CVB3 infection are not well understood. Given the important role for βarrs in the acute immune response, we tested the hypothesis that βarrs are necessary for the activation of the acute immune response and mediate the progression and severity of cardiotropic CVB3-induced myocarditis in mice. Five to 7-week-old mice devoid of βarr1 (βarr1 KO) or βarr2 (βarr2 KO) were infected intraperitoneally with 1x103-1x104 plaque forming units (PFU) of CVB3 per animal. Wild type (WT) C57BL/6 mice infected with CVB3 were used as controls. The survival rate 7 days post infection (dpi) was significantly improved in male βarr1 KOs (80%) and βarr2 KOs (75%) compared to male WT control mice (35%, p=0.013). Female WT, βarr1 KO, and βarr2 KO mice showed similar survival rates 7 dpi., ranging from 70% to 80%. Early mortality among all groups before 5 dpi was associated with high viral titers (~6.0 ± 0.5 log10PFU/mg) in the liver compared to mortality after 5 dpi (~2.4 ± 1.7 log10PFU/mg) as determined by plaque assay. Viral titers in the heart (WT=3.7 ± 0.9 log10PFU/mg, βarr1KO=3.6 ± 1.3 log10PFU/mg, βarr2KO=3.5 ± 1.2log10PFU/mg) were similar among all groups suggesting that βarrs are not involved in viral replication. Morphometric analysis showed similar weight loss (~18%) across all groups at 7 dpi corroborated by viral cardiac PFU. Immunofluorescent staining of the heart with the pan-inflammatory marker, CD45, revealed high immune cell infiltration in infected WT mice (34.2% ± 4.5%), whereas immune cell infiltration was significantly blunted in infected βarr1 KO (6.0% ± 1.1%; p<0.0001) and βarr2 KO (8.5% ± 0.9%; p<0.0001) mice. The degree of immune cell infiltration in hearts of infected WT mice was directly correlated with an increase in heart viral titer, whereas immune cell infiltration remained blunted across a broad range of heart viral titers in both βarr1 and 2 KO mice. The blunted immune response in both βarr KOs compared to WT infected controls was consistent across multiple immune cell markers including CD4 for helper T cells and CD11b for innate immune cells. In conclusion, we demonstrate that βarrs are necessary for immune cell recruitment to the heart in CVB3 myocarditis and deletion of βarrs in male mice may be cardioprotective as indicated by an increase in survival rate. These data suggest that βarrs may serve as potential therapeutic targets in the treatment of acute viral myocarditis. This work was supported by the National Institutes of Health Grants HL056687 (to H.A.R.). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

LncRNA XIST knockdown reduces myocardial damage in myocarditis by targeting the miR-140-3p/RIPK1 axis

ABSTRACT Viral myocarditis (MC) is caused by Coxsackie virus B3 (CVB3)-induced cardiomyocyte apoptosis and inflammation, and changes in miRNA and lncRNA are linked to cardiac remodeling. The long non-coding RNA XIST (XIST) has been identified as a regulator in various pathological processes in heart diseases, but its role in CVB3-induced MC is not well understood. This research aimed to evaluate the impact that XIST has on CVB3-induced MC as well as the mechanism behind this effect. XIST expression in CVB3-exposed H9c2 cells (H9c2 cells) was evaluated by qRT-PCR. In CVB3-exposed H9c2 cells, reactive oxygen species production, inflammatory mediators, and apoptosis were experimentally observed. An investigation into and confirmation of the existence of an interaction involving XIST, miR-140-3p, and RIPK1 were carried out. The findings showed that CVB3 induced upregulation of XIST in H9c2 cells. However, XIST knockdown reduced oxidative stress, inflammation, and apoptosis of CVB3-exposed H9c2 cells. XIST was specifically bound to miR-140-3p, and there was mutual negative regulation between the two. Moreover, XIST downregulated RIPK1, which was mediated by miR-140-3p. The study suggests that downregulating XIST can alleviate inflammatory injury in CVB3-exposed H9c2 cells through the miR-140-3p/RIPK1 axis. These findings provide novel insights into the underlying mechanisms of MC.