hKLK alleviates myocardial fibrosis in mice with viral myocarditis.

Myocardial fibrosis is the most serious complication of viral myocarditis (VMC). This study aimed to investigate the therapeutic benefits and underlying mechanisms of lentivirus-mediated human tissue kallikrein gene transfer in myocardial fibrosis in VMC mice. We established VMC mouse model via intraperitoneal injection with Coxsackie B3 virus. The effect was then assessed after treatment with vehicle, the empty lentiviral vectors (EZ.null), and the vectors expressing hKLK1 (EZ.hKLK1) via tail vein injection for 30 days, respectively. The results showed that administering EZ.hKLK1 successfully induced hKLK1 overexpression in mouse heart. Compared with EZ.null treatment, EZ.hKLK1 administration significantly reduced the heart/weight ratio, improved cardiac function, and ameliorated myocardial inflammation in VMC mice, suggesting that hKLK1 overexpression alleviates VMC in mice. EZ.hKLK1 administration also significantly abrogated the increased myocardial collagen content, type I/III collagen ratio, TGF-ß1 mRNA and protein expression in VMC mice, suggesting that hKLK1 overexpression reduces collagen accumulation and blunts TGF-ß1 signaling in the hearts of VMC mice. In conclusion, our results suggest that hKLK1 alleviates myocardial fibrosis in VMC mice, possibly by downregulating TGF-ß1 expression.

MicroRNA-30a-5p silencing polarizes macrophages toward M2 phenotype to alleviate cardiac injury following viral myocarditis by targeting SOCS1.

Viral myocarditis (VMC) is a life-threatening disease characterized by severe cardiac inflammation generally caused by coxsackievirus B3 (CVB3) infection. Several microRNAs (miRNAs or miRs) are known to play crucial roles in the pathogenesis of VMC. The study aimed to decipher the role of miR-30a-5p in the underlying mechanisms of VMC pathogenesis. We first quantified miR-30a-5p expression in a CVB3-induced mouse VMC model. The physiological characteristics of mouse cardiac tissues were then detected by hematoxylin and eosin (HE) and Picrosirius red staining. We established the correlation between miR-30a-5p and SOCS1, using dual-luciferase gene assay and Pearson's correlation coefficient. The expression of inflammatory factors (IFN-γ, IL-6, IL-10, and IL-13), M1 polarization markers [TNF-α, inducible nitric oxide synthase (iNOS)], M2 polarization markers (Arg-1, IL-10), and myocardial hypertrophy markers [atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)] was detected by RT-qPCR and Western blot analysis. miR-30a-5p was found to be highly expressed in VMC mice. Silencing of miR-30a-5p improved the cardiac function index and reduced heart weight-to-body weight ratio, myocardial tissue pathological changes and fibrosis degree, serological indexes, as well as proinflammatory factor levels, while enhancing anti-inflammatory factor levels in VMC mice. Furthermore, silencing of miR-30a-5p inhibited M1 polarization of macrophages while promoting M2 polarization in vivo and in vitro. SOCS1 was a target gene of miR-30a-5p, and the aforementioned cardioprotective effects of miR-30a-5p silencing were reversed upon silencing of SOCS1. Overall, this study shows that silencing of miR-30a-5p may promote M2 polarization of macrophages and improve cardiac injury following VMC via SOCS1 upregulation, constituting a potential therapeutic target for VMC treatment.NEW & NOTEWORTHY We found in this study that microRNA (miR)-30a-5p inhibition might improve cardiac injury following viral myocarditis (VMC) by accelerating M2 polarization of macrophages via SOCS1 upregulation. Furthermore, the anti-inflammatory mechanisms of miR-30a-5p inhibition may contribute to the development of new therapeutic strategies for VMC.

Low-intensity pulsed ultrasound attenuates cardiac inflammation of CVB3-induced viral myocarditis via regulation of caveolin-1 and MAPK pathways.

The aggressive immunological activity elicited by acute viral myocarditis contributes to a large amount of cardiomyocytes loss and poor prognosis of patients in clinic. Low-intensity pulsed ultrasound (LIPUS), which is an effective treatment modality for osteoarthropathy, has been recently illustrated regulating the overactive inflammatory response in various diseases. Here, we aimed to investigate whether LIPUS could attenuate coxsackievirus B3 (CVB3) infection-induced injury by coordinating the inflammatory response. Male BALB/c mice were inoculated intraperitoneally with CVB3 to establish the model of acute viral myocarditis. LIPUS treatment was given on Day 1, Day 1, 3 and Day 1, 3, 5 post-inoculation, respectively. All mice were followed up for 14 days. Day 1, 3, 5 LIPUS treatment significantly improved the survival rate, attenuated the ventricular dysfunction and ameliorated the cardiac histopathological injury of CVB3-infected mice. Western blotting analysis showed Day 1, 3, 5 LIPUS treatment decreased pro-inflammatory cytokines, increased the activation of caveolin-1 and suppressed p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) signallings in heart tissue. RAW264.7 cells were treated with lipopolysaccharides (LPS) to simulate the augmented inflammatory response in vivo. LIPUS treatment on RAW264.7 inhibited the expression of pro-inflammatory cytokines, activated caveolin-1 and suppressed p38 MAPK and ERK signallings. Transfecting RAW264.7 with caveolin-1 siRNA blunted the suppression of pro-inflammatory cytokines and MAPK signallings by LIPUS treatment. Taken together, we demonstrated for the first time that LIPUS treatment attenuated the aggressive inflammatory response during acute viral myocarditis. The underlying mechanism may be activating caveolin-1 and suppressing MAPK signallings.

Clinical characteristics and managements of severe hand, foot and mouth disease caused by enterovirus A71 and coxsackievirus A16 in Shanghai, China.

BACKGROUND: Hand, foot and mouth disease (HFMD) is a transmissible infectious disease caused by human enteroviruses (EV). Here, we described features of children with severe HFMD caused by EV-A71 or coxsackievirus A16 (CV-A16) in Shanghai, China. METHODS: Severe EV-A71 or CV-A16 caused HFMD children admitted to the Xinhua Hospital from January 2014 and December 2016, were recruited retrospectively to the study. Symptoms and findings at the time of hospitalization, laboratory tests, treatments, length of stay and residual findings at discharge were systematically recorded and analyzed. RESULTS: Of 19,995 children visited clinic service with probable HFMD, 574 children (2.87%) were admitted, 234 children (40.76%) were confirmed with EV-A71 (90/574) or CV-A16 (144/574) disease. Most (91.02%) of the patients were under 5 years. Initial clinical symptoms of EV-A71 and CV-A16 cases were: fever > 39 °C in 81 (90%) and 119 (82.63%), vomiting in 31 (34.44%) and 28 (19.44%), myoclonic twitching in 19 (21.11%) and 11(7.64%), startle in 21 (23.33%) and 20 (13.69%), respectively. Serum levels of interleukin-1ß (IL-1ß), IL-2, IL-6, IL-8, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) were significantly upregulated in severe HFMD subjects. Forty-seven children (20.08%) treated with intravenous gamma globulin (IVIG) showed decreased duration of illness episodes. All children were discharged without complications. CONCLUSIONS: EV-A71 and CV-A16 accounted 40.76% of admitted HFMD during 2014 to 2016 in Xinhua Hospital. IVIG appeared to be beneficial in shortening the duration of illness episodes of severe HFMD.

Enteroviruses in the early 21st century: new manifestations and challenges.

PURPOSE OF REVIEW: Enteroviruses cause a wide variety of diseases with neurologic, respiratory, skin, and gastrointestinal findings. The purpose of this review is to clarify changes in the classification of enteroviruses, provide information about recent disease outbreaks, and to summarize progress toward the treatment and prevention of these infections. RECENT FINDINGS: Enteroviruses are now classified into four distinct species. New variants of coxsackievirus B1, enterovirus-A71, and enterovirus-D68 (EV-D68) have emerged as causes of recent outbreaks in the United States and other countries, including more severe disease manifestations than previously described. EV-D68 now commonly circulates in the United States, and has been linked to severe respiratory disease and associated with acute flaccid myelitis (AFM). Overcoming enormous political and logistical challenges, fewer than 100 cases of polio have been reported in 2015, and the initiation of 'endgame' strategies appears imminent. Unfortunately, treatment for enterovirus infections remains supportive, although the recently completed pleconaril trial in newborns suggests that antiviral therapy may reduce mortality in neonatal disease. SUMMARY: Clinicians should be aware of the respiratory and neurological manifestations associated with EV-D68 and the potential for severe disease seen with other recently described enterovirus variants. Healthcare professionals should recognize the utility of rapid diagnostic methods and progress toward prevention and treatment of enterovirus infections.

Wnt11 gene therapy with adeno-associated virus 9 improves the survival of mice with myocarditis induced by coxsackievirus B3 through the suppression of the inflammatory reaction.

The wnt signaling pathway plays important roles in development and in many diseases. Recently several reports suggest that non-canonical Wnt proteins contribute to the inflammatory response in adult animals. However, the effects of Wnt proteins on virus-induced myocarditis have not been explored. Here, we investigated the effect of Wnt11 protein in a model of myocarditis induced by coxsackievirus B3 (CVB3) using recombinant adeno-associated virus 9 (rAAV9). The effect of Wnt11 gene therapy on a CVB3-induced myocarditis model was examined using male BALB/c mice. Mice received a single intravenous injection of either rAAV9-Wnt11 or rAAV9-LacZ 2 weeks before intraperitoneal administration of CVB3. Intravenous injection of the rAAV9 vector resulted in efficient, durable, and relatively cardiac-specific transgene expression. Survival was significantly greater among rAAV9-Wnt11 treated mice than among mice treated with rAAV9-LacZ (87.5% vs. 54.1%, P < 0.05). Wnt11 expression also reduced the infiltration of inflammatory cells, necrosis of the myocardium, and suppressed the mRNA expression of inflammatory cytokines. This is the first report to show that Wnt11 expression improves the survival of mice with CVB3-induced myocarditis. AAV9-mediated Wnt11 gene therapy produces beneficial effects on cardiac function and increases the survival of mice with CVB3-induced myocarditis through the suppression of both infiltration of inflammatory cells and gene expression of inflammatory cytokines.

Nucleotide differences of coxsackievirus B3 and chronic myocarditis.

The in vivo mechanisms in chronic myocarditis remain unclear. The aim of the current study was to clarify the genomic difference of amyocarditic (CB3O) and myocarditic (CB3M) coxsackievirus B3 (CB3) and the pathogenesis of in vivo mechanisms in chronic myocarditis. We examined the histopathology of CB3-inoculated wild-type (WT) and severe combined immunodeficient (SCID) mice with and without adoptive transfer of lymphocytes. There were no differences in viral growth between CB3O and CB3M. There were four to six nucleotide differences in the sequence of CB3O in comparison with the known CB3M. The difference in virus sequence between CB3O and CB3M was very minimal. The changes were located in 1A, 1C, and 1D regions, which encode the structural capsid proteins. Definite myocarditis developed in WT C3H (H-2(k)) inoculated with CB3M. On the contrary, trivial or mild myocarditis occurred in WT C3H mice inoculated with CB3O. In SCID C3H and SCID C57BL/6 (H-2(b)) mice, definite myocarditis developed by inoculation with both CB3O and CB3M. Myocardial lesion was less severe in the mice infected with CB3O than in those with CB3M. After anti-CD8 antibody treatment, myocarditis was easily induced in mice originally showing resistance to infection. In addition, chronic myocarditis developed in CB3O-infected SCID C3H mice reconstituted with CB3M-sensitized splenocytes of WT C3H mice. The development of chronic myocarditis primarily depends on the presence or absence of the virus genome, and secondarily on the complex interaction between virus virulence and immunological background of the host. CB3 infection may cause chronic myocarditis with ongoing inflammation with or without viral persistence.

MicroRNA profiling identifies microRNA-155 as an adverse mediator of cardiac injury and dysfunction during acute viral myocarditis.

RATIONALE: Viral myocarditis results from an adverse immune response to cardiotropic viruses, which causes irreversible myocyte destruction and heart failure in previously healthy people. The involvement of microRNAs and their usefulness as therapeutic targets in this process are unknown. OBJECTIVE: To identify microRNAs involved in viral myocarditis pathogenesis and susceptibility. METHODS AND RESULTS: Cardiac microRNAs were profiled in both human myocarditis and in Coxsackievirus B3-injected mice, comparing myocarditis-susceptible with nonsusceptible mouse strains longitudinally. MicroRNA responses diverged depending on the susceptibility to myocarditis after viral infection in mice. MicroRNA-155, -146b, and -21 were consistently and strongly upregulated during acute myocarditis in both humans and susceptible mice. We found that microRNA-155 expression during myocarditis was localized primarily in infiltrating macrophages and T lymphocytes. Inhibition of microRNA-155 by a systemically delivered LNA-anti-miR attenuated cardiac infiltration by monocyte-macrophages, decreased T lymphocyte activation, and reduced myocardial damage during acute myocarditis in mice. These changes were accompanied by the derepression of the direct microRNA-155 target PU.1 in cardiac inflammatory cells. Beyond the acute phase, microRNA-155 inhibition reduced mortality and improved cardiac function during 7 weeks of follow-up. CONCLUSIONS: Our data show that cardiac microRNA dysregulation is a characteristic of both human and mouse viral myocarditis. The inflammatory microRNA-155 is upregulated during acute myocarditis, contributes to the adverse inflammatory response to viral infection of the heart, and is a potential therapeutic target for viral myocarditis.

TRIF is a critical survival factor in viral cardiomyopathy.

TRIF is a member of the innate immune system known to be involved in viral recognition and type I IFN activation. Because IFNs are thought to play an important role in viral myocarditis, we investigated the role of TRIF in induced myocarditis in mice. Whereas C57BL/6 (wild-type) mice showed only mild myocarditis, including normal survival postinfection with coxsackievirus group B serotype 3 (CVB3), infection of TRIF(-/-) mice led to the induction of cardiac remodeling, severe heart failure, and 100% mortality (p < 0.0001). These mice showed markedly reduced virus control in cardiac tissues and cardiomyocytes. This was accompained with dynamic cardiac cytokine activation in the heart, including a suppression of the antiviral cytokine IFN-ß in the early viremic phase. TRIF(-/-) myocytes displayed a TLR4-dependent suppression of IFN-ß, and pharmacological treatment of CVB3-infected TRIF(-/-) mice with murine IFN-ß led to improved virus control and reduced cardiac inflammation. Additionally, this treatment within the viremic phase of myocarditis showed a significant long-term outcome indexed by reduced mortality (20 versus 100%; p < 0.001). TRIF is essential toward a cardioprotection against CVB3 infection.

Pharmacological and biological antiviral therapeutics for cardiac coxsackievirus infections.

Subtype B coxsackieviruses (CVB) represent the most commonly identified infectious agents associated with acute and chronic myocarditis, with CVB3 being the most common variant. Damage to the heart is induced both directly by virally mediated cell destruction and indirectly due to the immune and autoimmune processes reacting to virus infection. This review addresses antiviral therapeutics for cardiac coxsackievirus infections discovered over the last 25 years. One group represents pharmacologically active low molecular weight substances that inhibit virus uptake by binding to the virus capsid (e.g., pleconaril) or inactivate viral proteins (e.g., NO-metoprolol and ribavirin) or inhibit cellular proteins which are essential for viral replication (e.g., ubiquitination inhibitors). A second important group of substances are interferons. They have antiviral but also immunomodulating activities. The third and most recently discovered group includes biological and cellular therapeutics. Soluble receptor analogues (e.g., sCAR-Fc) bind to the virus capsid and block virus uptake. Small interfering RNAs, short hairpin RNAs and antisense oligonucleotides bind to and led to degradation of the viral RNA genome or cellular RNAs, thereby preventing their translation and viral replication. Most recently mesenchymal stem cell transplantation has been shown to possess antiviral activity in CVB3 infections. Taken together, a number of antiviral therapeutics has been developed for the treatment of myocardial CVB infection in recent years. In addition to low molecular weight inhibitors, biological therapeutics have become promising anti-viral agents.

Myocarditis and inflammatory cardiomyopathy: current evidence and future directions.

Inflammatory cardiomyopathy, characterized by inflammatory cell infiltration into the myocardium and a high risk of deteriorating cardiac function, has a heterogeneous aetiology. Inflammatory cardiomyopathy is predominantly mediated by viral infection, but can also be induced by bacterial, protozoal or fungal infections as well as a wide variety of toxic substances and drugs and systemic immune-mediated diseases. Despite extensive research, inflammatory cardiomyopathy complicated by left ventricular dysfunction, heart failure or arrhythmia is associated with a poor prognosis. At present, the reason why some patients recover without residual myocardial injury whereas others develop dilated cardiomyopathy is unclear. The relative roles of the pathogen, host genomics and environmental factors in disease progression and healing are still under discussion, including which viruses are active inducers and which are only bystanders. As a consequence, treatment strategies are not well established. In this Review, we summarize and evaluate the available evidence on the pathogenesis, diagnosis and treatment of myocarditis and inflammatory cardiomyopathy, with a special focus on virus-induced and virus-associated myocarditis. Furthermore, we identify knowledge gaps, appraise the available experimental models and propose future directions for the field. The current knowledge and open questions regarding the cardiovascular effects associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are also discussed. This Review is the result of scientific cooperation of members of the Heart Failure Association of the ESC, the Heart Failure Society of America and the Japanese Heart Failure Society.

Notes from the field: acute hemorrhagic conjunctivitis outbreaks caused by coxsackievirus A24v --- Uganda and southern Sudan, 2010.

CDC was contacted on June 22, 2010, by the Ugandan Ministry of Health (MoH)/Uganda Virus Research Institute and on July 11 by the Government of Southern Sudan (GOSS) via the CDC Global Disease Detection Regional Center in Kenya to perform diagnostic laboratory testing on conjunctival swabs from persons with "red eye syndrome." Widespread, ongoing outbreaks of acute hemorrhagic conjunctivitis (AHC) have been observed in Uganda and Southern Sudan since spring 2010. AHC becomes a reportable condition in outbreak settings. Case numbers were estimated in Uganda after MoH confirmation of reported cases from district health facilities and, in Southern Sudan, after a medical record review in six health facilities. To date, 6,818 cases from 26 districts in Uganda, and 428 cases in Juba, Southern Sudan, have been counted; however, because most cases are not reported, these totals are considered underestimates.

Generation of neutralizing monoclonal antibodies against Enterovirus 71 using synthetic peptides.

Enterovirus 71 (EV71) has led to recent outbreaks of hand, foot and mouth disease (HFMD) in China, resulting in high mortality. In this study, several monoclonal antibodies were generated by immunizing mice with two synthetic peptides, SP55 and SP70, containing amino acids 163-177 and 208-222 of VP1. The specificities of the anti-EV71 peptide monoclonal antibodies were confirmed by Western blot analysis and immunocytochemistry against EV71 virus. Most importantly, we have identified a monoclonal antibody, clone 22A12, which shows strong neutralizing activity against EV71 in an in vitro neutralization assay. Because there is no vaccine available and treatment is very limited, mouse anti-EV71 monoclonal antibody, clone 22A12, could be a promising candidate to be humanized and used for treatment of EV71 infection.

Coxsackieviruses and quasispecies theory: evolution of enteroviruses.

Enterovirus populations display quasispecies dynamics, characterized by high rates of mutation and recombination, followed by competition, selection, and random drift acting on heterogeneous mutant spectra. Direct experimental evidence indicates that high mutation rates and complex mutant spectra can serve for the adaptation of enteroviruses to complex environments. Studies with the RNA-dependent RNA polymerase of picornaviruses suggest that multiple enzyme sites may influence the template-copying fidelity (incorporation of incorrect vs correct nucleotide) during RNA replication. Mutation and recombination are an unavoidable consequence of the molecular mechanisms inherent to the process of viral genome replication and underlie the diversification of enterovirus genomes as they multiply in human and animal hosts. The diversity of disease manifestations associated with closely related enteroviruses is probably attributable to profound biological effects of some mutations that, because of their limited number, do not necessarily affect the phylogenetic position of the virus. The combination of highly dynamic mutant spectra with unpredictable alterations of biological behavior by minimal genetic change defies classical classification schemes. The result is the need to update the grouping of enteroviruses quite frequently into genetic and serological types and subtypes. The tolerance of enterovirus genomes to remain replication-competent despite multiple mutation and recombination events encourages the engineering of live-attenuated vaccines. Also, the application of quasispecies theory to an understanding of the limits of viral genomes to accept mutations, together with an increasingly deeper understanding of the mechanisms of mutagenesis by nucleoside analogs, has paved the way for the application of lethal mutagenesis as a new antiviral strategy.

The impact of CVB3 infection on host cell biology.

CVB3 myocarditis can lead to dilated cardiomyopath (DCM). DCM is one of the leading causes of the need for heart transplantation, so it is important to understand the life cycle of CVB3 and its interactions with the host cell. Infection causes rapid death of host cardiomyocytes by altering normal cellular homeostasis for the efficient release of progeny virion. In this chapter, we will examine the impact that CVB3 replication has on host cell biology, from events that take place at receptor ligation to progeny virus release. The primary focus will be on the myriad of signalling pathways that are activated at all stages of virus replication and their downstream effects. We will also discuss some of the extracellular effects of infection as well as immune and matrixmetalloprotease activation. Interactions of host cell proteins with the 5' untranslated region (UTR) are required for translation and replication of CVB3. These interactions do not always benefit the virus since the interactions of a 28-kDa host protein with the 5' UTR are thought to be responsible for inhibitory activity against CVB3. Finally, we will discuss how the elucidation of the different stages of replication has provided the opportunity to develop novel strategies for combating CVB3 infection.

Pediatric group B coxsackievirus infections.

The CVB have long been recognized as significant pathogens of infants and children. Although the major route for transmission of the CVB is fecal-oral, vertical transmission from mother to infant is also possible. This review will focus on the more common or clinically relevant CVB-related syndromes, their diagnosis, treatment, and prevention.

Cardiac-targeted RNA interference mediated by an AAV9 vector improves cardiac function in coxsackievirus B3 cardiomyopathy.

RNA interference (RNAi) has potential to be a novel therapeutic strategy in diverse areas of medicine. In this paper, we report on targeted RNAi for the treatment of a viral cardiomyopathy, which is a major cause of sudden cardiac death or terminal heart failure in children and young adults. RNAi therapy employs small regulatory RNAs to achieve its effect, but in vivo use of synthetic small interfering RNAs is limited by instability in plasma and low transfer into target cells. We instead evaluated an RNAi strategy using short hairpin RNA (shRdRp) directed at the RNA polymerase (RdRP) of coxsackievirus B3 (CoxB3) in HeLa cells, primary rat cardiomyocytes (PNCMs) and CoxB3-infected mice in vivo. A conventional AAV2 vector expressing shRdRp protected HeLa against virus-induced death, but this vector type was unable to transduce PNCMs. In contrast, an analogous pseudotyped AAV2.6 vector was protective also in PNCMs and reduced virus replication by >3 log10 steps. Finally, we evaluated the intravenous treatment of mice with an AAV2.9-shRdRp vector because AAV9 carries the most cardiotropic AAV capsid currently known for in vivo use. Mice with CoxB3 cardiomyopathy had disturbed left ventricular (LV) function with impaired parameters of contractility (dP/dtmax = 3,006 +/- 287 vs. 7,482 +/- 487 mmHg/s, p < 0.01) and diastolic relaxation (dP/dtmin = -2,224 +/- 195 vs. -6,456 +/- 356 mmHg/s, p < 0.01 and Tau = 16.2 +/- 1.1 vs. 10.7 +/- 0.6 ms, p < 0.01) compared to control mice. AAV2.9-shRdRp treatment significantly attenuated the cardiac dysfunction compared to control vector-treated mice on day 10 after CoxB3 infection: dP/dtmax = 3,865 +/- 354 vs. 3,006 +/- 287 mmHg/s (p < 0.05), dP/dtmin = -3,245 +/- 231 vs. -2,224 +/- 195 mmHg/s (p < 0.05) and Tau = 11.9 +/- 0.5 vs. 16.2 +/- 1.1 ms (p < 0.01). The data show, for the first time, that intravenously injected AAV9 has the potential to target RNAi to the heart and suggest AAV9-shRNA vectors as a novel therapeutic approach for cardiac disorders.

Exosomes derived from cardiac progenitor cells attenuate CVB3-induced apoptosis via abrogating the proliferation of CVB3 and modulating the mTOR signaling pathways.

Viral myocarditis is potentially fatal and lacking a specific treatment. Exosomes secreted by cardiac progenitor cells (CPCs) have emerged as a promising tool for cardioprotection and repair. In this study, we investigated whether CPCs-derived exosomes (CPCs-Ex) could utilize the mTOR signal pathway to reduce the apoptosis in viral myocarditis. In vitro, exosomes were, respectively, added to H9C2 cells after CVB3 infection to detect the anti-apoptosis effect of CPCs-Ex. Compared with the controls, the apoptosis rate was reduced, accompanied with the depressed expression of viral capsid protein 1 (VP1) and pro-apoptosis factors of Bim/caspase families. Meanwhile, the phosphorylation of Akt, mTOR, and p70S6K were promoted, but that of 4EBP1 was suppressed. In vivo, the results of apoptosis, expression of CVB3 and pro-apoptosis factors, and phosphorylation of Akt/mTOR factors of CVB3-infected cardiomyocytes were consistent with that of vitro. Following that, we use Rapamycin and MK-2206 to inhibit the Akt/mTOR signaling pathway, meanwhile, Rattus 4EBP1, p70S6K, Akt1 and Akt2 were transfected to H9C2 cells to establish the stably transfected cell lines. In the group with Rapamycin or MK-2206 pretreatment, CPCs-Ex also could decrease the apoptosis of H9C2 cells and expression of CVB3 mRNA, followed by decreased expression of apoptosis factors. In Akt2, p70S6K and 4EBP1 overexpression groups, CPCs-Ex promoted CVB3-induced apoptosis, VP1 expression and cleavage of caspase-3. Our results therefore identify CPCs-Ex exerts an anti-apoptosis effect in CVB3-infected cells by abrogating the proliferation of CVB3 and modulating the mTOR signaling pathways as well as the expression of Bcl-2 and caspase families. Viral myocarditis, mainly caused by CVB3 infection, is lacking a specific treatment. Our study identified an anti-apoptosis role of CPCs-Ex in CVB3-infected cells and rats, which shown that CPCs-Ex may be an effective tool to treat viral myocarditis. We believe that with more in-depth research on the functionality of CPCs-Ex, there will be a breakthrough in the treatment of viral myocarditis.