Gene therapy with CCL2 (MCP-1) mutant protects CVB3-induced myocarditis by compromising Th1 polarization

Myricetin ameliorates experimental autoimmune myocarditis in mice by modulating immune response and inhibiting MCP-1 expression

Myocarditis is defined as an inflammatory disease of the myocardium, and the autoimmune response specific to myocardium plays an important role in chronic myocarditis. Inhibiting myocardial-specific autoimmune response and inflammation is crucial to treat myocarditis. Myricetin is a plant-derived flavonoid in nature which has potent anti-inflammatory and cardiovascular protective properties. However, the pharmacological effect of myricetin in autoimmune myocarditis is undefined. It is necessary to investigate the role and potential mechanisms of myricetin in autoimmune myocarditis. Therefore, purified cardiac myosin was subcutaneously injected to mice to establish the experimental autoimmune myocarditis (EAM) model. Myricetin was solubilized in normal saline and administered everyday by gavage from the day of immunization. After 21 days of treatment, it was found that myricetin significantly alleviated myocardial injury in EAM mice. The serum anti-cardiac myosin antibody, immunoglobulin (Ig) G, IgM levels and the proportion of T helper 17 (Th17) cells were decreased and the proportion of regulatory T (Treg) cells was increased with the treatment of myricetin in EAM mice. The myosin-specific T cell proliferation was inhibited by myricetin. Meanwhile, myricetin suppressed the expressions of monocyte chemoattractant protein-1 (MCP-1), phospho (p)-p65, p-c-Jun and Act1/TRAF6/TAK1 in H9C2 cells and myocardial tissues of EAM mice. These results revealed that myricetin inhibited the autoimmune response specific to myocardium and the expression of MCP-1 in cardiomyocytes, which suggested that myricetin ameliorated autoimmune myocarditis by modulating immune response and the expression of MCP-1. Therefore, myricetin may be a promising therapeutic strategy for autoimmune myocarditis.

Dysregulation and imbalance of innate and adaptive immunity are involved in the cardiomyopathy progression

Background

Cardiomyopathy is known to be a heterogeneous disease with numerous etiologies. They all have varying degrees and types of myocardial pathological changes, resulting in impaired contractility, ventricle relaxation, and heart failure. The purpose of this study was to determine the pathogenesis, immune-related pathways and important biomarkers engaged in the progression of cardiomyopathy from various etiologies.

Methods

We downloaded the gene microarray data from the Gene Expression Omnibus (GEO). The hub genes between cardiomyopathy and non-cardiomyopathy control groups were identified using differential expression analysis, least absolute shrinkage and selection operator (LASSO) regression and weighted gene co-expression network analysis (WGCNA). To assess the diagnostic precision of hub genes, receiver-operating characteristic (ROC) curves as well as the area under the ROC curve (AUC) were utilized. Then, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analysis and Gene Ontology (GO) analysis were conducted on the obtained differential genes. Finally, single-sample GSEA (ssGSEA) and Gene Set Enrichment Analysis (GSEA) were utilized to analyze the infiltration level of 28 immune cells and their relationship with hub genes based on gene expression profile data and all differential gene files.

Results

A total of 82 differentially expressed genes (DEGs) were screened after the training datasets were merged and intersected. The WGCNA analysis clustered the expression profile data into four co-expression modules, The turquoise module exhibited the strongest relationship with clinical traits, and nine candidate key genes were obtained from the module. Then we intersected DEGs with nine candidate genes. LASSO regression analysis identified the last three hub genes as promising biomarkers to distinguish the cardiomyopathy group from the non-cardiomyopathy control group. ROC curve analysis in the validation dataset revealed the sensitivity and accuracy of three hub genes as marker genes. The majority of the functional enrichment analysis results were concentrated on immunological and inflammatory pathways. Immune infiltration analysis revealed a significant correlation between regulatory T cells, type I helper T cells, macrophages, myeloid-derived suppressor cells, natural killer cells, activated dendritic cells and the abundance of immune infiltration in hub genes.

Conclusion

The hub genes (CD14, CCL2, and SERPINA3) can be used as markers to distinguish cardiomyopathy from non-cardiomyopathy individuals. Among them, SERPINA3 has the best diagnostic performance. T cell immunity (adaptive immune response) is closely linked to cardiomyopathy progression. Hub genes may protect the myocardium from injury through myeloid-derived suppressor cells, regulatory T cells, helper T cells, monocytes/macrophages, natural killer cells and activated dendritic cells. The innate immune response is crucial to this process. Dysregulation and imbalance of innate immune cells or activation of adaptive immune responses are involved in cardiomyopathy disease progression in patients.

Role of the CCL2-CCR2 axis in cardiovascular disease: Pathogenesis and clinical implications

The CCL2-CCR2 axis is one of the major chemokine signaling pathways that has received special attention because of its function in the development and progression of cardiovascular disease. Numerous investigations have been performed over the past decades to explore the function of the CCL2-CCR2 signaling axis in cardiovascular disease. Laboratory data on the CCL2-CCR2 axis for cardiovascular disease have shown satisfactory outcomes, yet its clinical translation remains challenging. In this article, we describe the mechanisms of action of the CCL2-CCR2 axis in the development and evolution of cardiovascular diseases including heart failure, atherosclerosis and coronary atherosclerotic heart disease, hypertension and myocardial disease. Laboratory and clinical data on the use of the CCL2-CCR2 pathway as a targeted therapy for cardiovascular diseases are summarized. The potential of the CCL2-CCR2 axis in the treatment of cardiovascular diseases is explored.

The Role of B Cells in Regulation of Th Cell Differentiation in Coxsackievirus B3-Induced Acute Myocarditis

Viral myocarditis (VMC) is the major cause of sudden death in adolescents. To date, no effective treatment has been identified for VMC. Studies have shown that T helper (Th) cells such as Th1, Th2, Th17, and Th22 cells are involved in the pathogenesis of VMC. However, the role of B cells and their impact on Th cells in VMC is unclear. In this study, we investigated the role of B cells in Th cell differentiation in myocardial damage in an animal model of VMC. C57BL/6 mice were infected with Coxsackievirus B3 (CVB3) intraperitoneally or injected with phosphate-buffered saline as a control condition. At day 7, samples from these mice were analyzed by histology, ELISA, flow cytometry, and gene expression assays. We found that TNF-α-, IL-6-, and IL-17-producing B cell numbers were significantly increased, while IL-4-producing B cell population was significantly reduced in acute VMC. Furthermore, we performed B cell knockout (BKO), SCID, and SCID+B cells reconstitution experiments. We found that BKO alleviated the cardiac damage following CVB3 infection, may hamper the differentiation of Th1 and Th17 cells, may promote the differentiation of Th2 cells, and proved ineffective for the differentiation of Th22 cells. In contrast, SCID+B cells reconstitution experiment exacerbated the cardiac damage. Ex vivo studies further revealed that B cells promote the differentiation of Th1 and Th17 cells and inhibit the differentiation of Th2 cells. Our study shows that B cells are activated and have strong abilities of antigen presentation and producing cytokines in VMC; B cells not only play a pathogenic role in VMC independent of T cells but also promote Th1 and Th17 cell differentiation, and hamper Th2 cell differentiation in VMC.

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

Viral myocarditis (VMC) is a cardiac disease associated with myocardial inflammation and injury induced by virus infection. Cardiomyocytes have recently been regarded as key players in eliciting and modulating inflammation within the myocardium. Kruppel-like factor 10 (KLF10) is a crucial regulator of various pathological processes and plays different roles in a variety of diseases. However, its role in VMC induced by coxsackievirus B3 (CVB3) infection remains unknown. In this study, we report that cardiac KLF10 confers enhanced protection against viral myocarditis. We found that KLF10 expression was downregulated upon CVB3 infection. KLF10 deficiency enhanced cardiac viral replication and aggravated VMC progress. Bone marrow chimera experiments indicated that KLF10 expression in nonhematopoietic cells was involved in the pathogenesis of VMC. We further identified MCP-1 as a novel target of KLF10 in cardiomyocytes, and KLF10 cooperated with histone deacetylase 1 (HDAC1) to negatively regulate MCP-1 expression by binding its promoter, leading to activation of MCP-1 transcription and recruitment of Ly6C^high monocytes/macrophages into the myocardium. This novel mechanism of MCP-1 regulation by KLF10 might provide new insights into the pathogenesis of VMC and a potential therapeutic target for VMC.

The cholinergic anti-inflammatory pathway ameliorates acute viral myocarditis in mice by regulating CD4+ T cell differentiation

Many studies have found that abnormalities in the proportion and differentiation of CD4⁺ T cells (Th cells) are closely related to the pathogenesis of viral myocarditis (VMC). Our previous research indicates that the cholinergic anti-inflammatory pathway (CAP) attenuates the inflammatory response of VMC and downregulates the expression of cytokines in Th1 and Th17 cells. This suggests that the cholinergic anti-inflammatory pathway likely attenuates the inflammatory response in VMC by altering Th cell differentiation. The aim of this study is to investigate the effect of CAP on CD4⁺ T cell differentiation in VMC mice. CD4⁺ T cells in the spleen of VMC mice were obtained and cultured in the presence of nicotine or methyllycaconitine (MLA). Cells were harvested and analyzed for the percentage of each Th cell subset by flow cytometry and transcription factor release by Western blot. Then, we detected the effect of CAP on the differentiation of Th cells in vivo. Nicotine or MLA was used to activate and block CAP, respectively, in acute virus-induced myocarditis. Nicotine treatment increased the proportion of Th2 and Treg cells, decreased the proportion of Th1 and Th17 cells in the spleen, reduced the level of proinflammatory cytokines, and attenuated the severity of myocardium lesions and cellular infiltration in viral myocarditis. MLA administration had the opposite effect. Our result demonstrated that CAP effectively protects the myocardium from virus infection, which may be attributable to the regulation of Th cell differentiation.

CD80 Regulates Th17 Cell Differentiation in Coxsackie Virus B3-Induced Acute Myocarditis

The cluster of differentiation protein complex, CD80/CD86, regulates Th1/Th2 differentiation in autoimmune disease. In order to establish the effects of CD80/CD86 on Th17 cell differentiation in acute viral myocarditis (VMC), we infected C57BL/6 mice with Coxsackie virus B3 (CVB3) and examined the effects of the treatment with anti-CD80/CD86 monoclonal antibodies (mAbs) on Th17 cell differentiation in vivo. The effects of anti-CD80/CD86 mAbs on Th17 cell differentiation were further evaluated in vitro. The treatment with anti-CD80 mAb induced marked suppression of Th17 cell differentiation and ROR-γt mRNA expression, whereas anti-CD86 mAb alone had no effect, both in vivo and in vitro. Our finding that CD80 regulates Th17 differentiation supports the potential utility of anti-CD80 mAb as an effective new immunotherapeutic target in acute VMC.

Gr-1+ Cells Other Than Ly6G+ Neutrophils Limit Virus Replication and Promote Myocardial Inflammation and Fibrosis Following Coxsackievirus B3 Infection of Mice

Coxsackievirus B3 (CVB3) is the primary cause of viral myocarditis. An early and abundant neutrophil accumulation in the myocardium is a hallmark of early CVB3 infection. Yet the relative contribution of neutrophils to host susceptibility to CVB3 myocarditis remains largely unknown. Herein, peripheral neutrophil depletion was implemented in a BALB/c mouse model of acute CVB3 myocarditis using the specific 1A-8 (anti-Ly6G) or a RB6-8C5 (anti-Gr-1) mAb covering a wide range. Anti-Ly6G treatment led to systemic neutropenia throughout the disease, but did not alter virus replication, disease susceptibility and histopathological changes in the heart and pancreas of mice. In contrast, depletion of both neutrophils and monocytes/macrophages by anti-Gr-1 mAb prior to and after infection significantly promoted susceptibility of mice to CVB3 infection which was associated with exacerbated cardiac and pancreatic viral load. However, depletion of Gr1+ cells significantly suppressed acute myocarditis and pancreatic acini destruction at day 7 post infection via reducing Ly6C^high monocyte population in the circulation. Additionally, cardiac interstitial fibrosis was not affected by neutrophil depletion, whereas Gr-1+ cells other than neutrophils increased cardiac fibrosis at day 21 p.i. by increasing cardiac expression of profibrotic cytokine TNF-α and TGF-β. Thus, Neutrophil function is most likely not essential for CVB3 control and peripheral neutrophils play dispensable role in the pathogenesis of acute myocarditis and pancreatitis during CVB3 infection. Whereas Gr-1+ cells other than neutrophils play a major role in limiting viral replication while promoting myocardial and pancreatic inflammatory injury and fibrosis.

Case report of severe myocarditis in an immunocompromised child with Respiratory Syncytial Virus infection

Background

Respiratory syncytial virus (RSV) infection is common and may be severe among patients with preexisting cardiac anomalies, but direct involvement of myocardial damage is not common in those patients. Additionally, myocardial involvement has been rarely described among immune compromised children.

Case presentation

A 4-year-old girl with acute lymphoblastic leukemia who received maintenance chemotherapy in an outpatient clinic developed systemic inflammatory response syndrome. RSV infection was confirmed by a positive rapid antigen test and serological assay. Subsequently, she was diagnosed with severe myocarditis caused by RSV infection, which was diagnosed by abnormal findings of cardiac echography and ECG and elevated biomarkers for myocardial damage. Then, she was treated in the intensive care unit for 13 days. High amounts of RSV type B RNA was detected in tracheal aspirates and serum sample.

Conclusion

This case report emphasizes that RSV infection may be associated with myocarditis in immunocompromised children receiving maintenance chemotherapy.

New Insights into the Immunobiology of Mononuclear Phagocytic Cells and Their Relevance to the Pathogenesis of Cardiovascular Diseases

Macrophages are the primary immune cells that reside within the myocardium, suggesting that these mononuclear phagocytes are essential in the orchestration of cardiac immunity and homeostasis. Independent of the nature of the injury, the heart triggers leukocyte activation and recruitment. However, inflammation is harmful to this vital terminally differentiated organ with extremely poor regenerative capacity. As such, cardiac tissue has evolved particular strategies to increase the stress tolerance and minimize the impact of inflammation. In this sense, growing evidences show that mononuclear phagocytic cells are particularly dynamic during cardiac inflammation or infection and would actively participate in tissue repair and functional recovery. They respond to soluble mediators such as metabolites or cytokines, which play central roles in the timing of the intrinsic cardiac stress response. During myocardial infarction two distinct phases of monocyte influx have been identified. Upon infarction, the heart modulates its chemokine expression profile that sequentially and actively recruits inflammatory monocytes, first, and healing monocytes, later. In the same way, a sudden switch from inflammatory macrophages (with microbicidal effectors) toward anti-inflammatory macrophages occurs within the myocardium very shortly after infection with Trypanosoma cruzi, the causal agent of Chagas cardiomyopathy. While in sterile injury, healing response is necessary to stop tissue damage; during an intracellular infection, the anti-inflammatory milieu in infected hearts would promote microbial persistence. The balance of mononuclear phagocytic cells seems to be also dynamic in atherosclerosis influencing plaque initiation and fate. This review summarizes the participation of mononuclear phagocyte system in cardiovascular diseases, keeping in mind that the immune system evolved to promote the reestablishment of tissue homeostasis following infection/injury, and that the effects of different mediators could modulate the magnitude and quality of the immune response. The knowledge of the effects triggered by diverse mediators would serve to identify new therapeutic targets in different cardiovascular pathologies.

MCPIP1 inhibits coxsackievirus B3 replication by targeting viral RNA and negatively regulates virus-induced inflammation

Monocyte chemotactic protein-induced protein 1(MCPIP1) is identified as an important inflammatory regulator during immune response. MCPIP1 possesses antiviral activities against several viruses, such as Japanese encephalitis. However, its role on Coxsackievirus B3 (CVB3) infection, a positive-stranded RNA virus, has not been addressed. Here, we reported that MCPIP1 was up-regulated in cardiomyocytes by CVB3 infection and in hearts and pancreas of infected mice. Then we found that overexpression of MCPIP1 inhibited CVB3 replication and knockdown of it promoted virus replication. Luciferase assay demonstrated MCPIP1 targeting non-ARE region of CVB3 3'UTR, which was dependent on its RNase, RNA binding and oligomerization abilities, but not deubiquitinase activity. We further verified that MCPIP1 negatively regulated CVB3-induced inflammatory response in macrophages. Thus, our data suggest MCPIP1 as a potent host defense against CVB3 infection and viral myocarditis.

Methods for Testing Immunological Factors

Hypersensitivity reactions can be elicited by various factors: either immunologically induced, i.e., allergic reactions to natural or synthetic compounds mediated by IgE, or non-immunologically induced, i.e., activation of mediator release from cells through direct contact, without the induction of, or the mediation through immune responses. Mediators responsible for hypersensitivity reactions are released from mast cells. An important preformed mediator of allergic reactions found in these cells is histamine. Specific allergens or the calcium ionophore 48/80 induce release of histamine from mast cells. The histamine concentration can be determined with the o-phthalaldehyde reaction.

Inhibition of Histone Deacetylase Activity Aggravates Coxsackievirus B3-Induced Myocarditis by Promoting Viral Replication and Myocardial Apoptosis

Viral myocarditis, which is most prevalently caused by coxsackievirus B3 (CVB3), is a serious clinical condition characterized by excessive myocardial inflammation. Recent studies suggest that regulation of protein acetylation levels by inhibiting histone deacetylase (HDAC) activity modulates inflammatory response and shows promise as a therapy for several inflammatory diseases. However, the role of HDAC activity in viral myocarditis is still not fully understood. Here, we aim to investigate the role of HDAC activity in viral myocarditis and its underlying mechanism. CVB3-infected BALB/c mice were treated with the HDAC inhibitor (HDACI) suberoylanilide hydroxamic acid (SAHA) or trichostatin A (TSA). We found inhibition of HDAC activity aggravated rather than ameliorated the severity of CVB3-induced myocarditis, which was contrary to our expectations. The aggravated myocarditis by HDACI treatment seemed not to be caused by an elevated inflammatory response but by the increased CVB3 replication. Further, it was revealed that the increased CVB3 replication was closely associated with the HDACI-enhanced autophagosome formation. Inhibition of autophagosome formation by wortmannin or ATG5 short hairpin RNA dramatically suppressed the HDACI-increased CVB3 replication. The increased viral replication subsequently elevated CVB3-induced myocardial apoptosis. Conversely, inhibition of CVB3 replication and ensuing myocardial apoptosis by the antiviral drug ribavirin significantly reversed the HDACI-aggravated viral myocarditis. In conclusion, we elucidate that the inhibition of HDAC activity increases CVB3 replication and ensuing myocardial apoptosis, resulting in aggravated viral myocarditis. Possible adverse consequences of administering HDACI should be considered in patients infected (or coinfected) with CVB3.

IMPORTANCE Viral myocarditis, which is most prevalently caused by CVB3, is characterized by excessive myocardial inflammation. Inhibition of HDAC activity was originally identified as a powerful anti-cancer therapeutic strategy and was recently found to be implicated in the regulation of inflammatory response. HDACI has been demonstrated to be efficacious in animal models of several inflammatory diseases. Thus, we hypothesize that inhibition of HDAC activity also protects against CVB3-induced viral myocarditis. Surprisingly, we found inhibition of HDAC activity enhanced myocardial autophagosome formation, which led to the elevated CVB3 viral replication and ensuing increased myocardial apoptosis. Viral myocarditis was eventually aggravated rather than ameliorated by HDAC inhibition. In conclusion, we elucidate the role of HDAC activity in viral myocarditis. Moreover, given the importance of HDACI in preclinical and clinical treatments, the possible unfavorable effect of HDACI should be carefully evaluated in patients infected with viruses, including CVB3.

Immunologic Network and Response to Intramyocardial CD34+ Stem Cell Therapy in Patients With Dilated Cardiomyopathy

BACKGROUND

Although stem cell therapy (SCT) is emerging as a potential treatment for patients with dilated cardiomyopathy (DCM), clinical response remains variable. Our objective was to determine whether baseline differences in circulating immunologic and nonimmunologic biomarkers may help to identify patients more likely to respond to intramyocardial injection of CD34(+)-based SCT.

METHODS AND RESULTS

We enrolled from January 3, 2011 to March 5, 2012 37 patients with longstanding DCM (left ventricular ejection fraction [LVEF] <40%, New York Heart Association functional class III) who underwent peripheral CD34(+) stem cell mobilization with granulocyte colony-stimulating factor (G-CSF) and collection by means of apheresis. CD34(+) cells were labeled with (99m)Tc-hexamethylpropyleneamine oxime to allow assessment of stem cell retention at 18 hours. Response to SCT was predefined as an increase in LVEF of ≥5% at 3 months. The majority (84%) of patients were male with an overall mean LVEF of 27 ± 7% and a median N-terminal pro-B-type natriuretic peptide (NT-proBNP) level of 2,774 pg/mL. Nineteen patients (51%) were responders to SCT. There was no significant difference between responders and nonresponders regarding to age, sex, baseline LVEF, NT-proBNP levels, or 6-minute walking distance. With the use of a partial least squares (PLS) predictive model, we identified 9 baseline factors that were associated with both stem cell response and stem cell retention (mechanistic validation). Among the baseline factors positively associated with both clinical response and stem cell retention were G-CSF, SDF-1, LIF, MCP-1, and MCP-3. Among baseline factors negatively associated with both clinical response and retention were IL-12p70, FASL, ICAM-1, and GGT. A decrease in G-CSF at 3-month follow-up was also observed in responders compared with nonresponders (P = .02).

CONCLUSIONS

If further validated, baseline immunologic and nonimmunologic biomarkers may help to identify patients with DCM who are more likely to respond to CD34(+)-based SCT.

Endoplasmic Reticulum Stress Aggravates Viral Myocarditis by Raising Inflammation Through the IRE1-Associated NF-κB Pathway

BACKGROUND

Viral myocarditis, which is mostly caused by coxsackievirus infection, is characterized by myocardial inflammation. Abnormal endoplasmic reticulum (ER) stress participates in many heart diseases, but its role in viral myocarditis remains unsolved.

METHODS

We investigated the influence of ER stress in coxsackievirus B3 (CVB3)-induced viral myocarditis by dynamically detecting its activation in CVB3-infected hearts, analyzing its association with myocarditis severity, and exploring its impact on disease development by modulating the strength of ER stress with the chemical activator tunicamycin (Tm) or the inhibitor tauroursodeoxycholic acid (TUDCA). The underlying signal pathway of ER stress in CVB3-induced myocarditis was also deciphered.

RESULTS

We found that myocardial expression of Grp78 and Grp94, 2 ER stress markers, was significantly increased after CVB3 infection and positively correlated with myocarditis severity. Consistently, Tm-augmented ER stress obviously aggravated myocarditis, as shown by more severe myocardial inflammation, reduced cardiac function, and a lower survival rate, whereas TUDCA decreased ER stress and obviously alleviated myocarditis. This pathologic effect of ER stress could be attributed to increased levels of proinflammatory cytokine (interleukin [IL]-6, IL-12, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1) production through the IRE1-associated nuclear factor-κB (NF-kB) pathway.

CONCLUSIONS

ER stress accentuated CVB3-induced myocardial inflammation through the IRE1-associated NF-κB pathway. This study may help us understand the role of ER stress in viral myocarditis and promote the development of corresponding therapeutic strategies based on manipulating ER stress.

Inhibition of IL-2 inducible T-cell kinase alleviates T-cell activation and murine myocardial inflammation associated with CVB3 infection

BACKGROUND

Coxsackievirus B3 (CVB3) infection causes myocarditis, pancreatitis, and aseptic meningitis. Targeting antigen-specific T cell reactions might be a promising way to alleviate the inflammatory response induced by CVB3 infection. IL-2-inducible T-cell kinase (ITK), a member of Tec kinase family expressed mainly in T cells, plays an important role in the activation of T cells. The role of ITK in viral myocarditis induced by CVB3 has not been documented.

METHODOLOGY

In this study, we inhibited the ITK expression in Jurkat cells, primary human peripheral blood mononuclear cells (PBMC), and mouse splenocytes by ITK-specific siRNA. The inhibition efficiently suppressed cell proliferation (P<0.05) and T-cell related cytokine secretion (P<0.05). In order to inhibit ITK in vivo, the pGCSIL plasmid containing short hairpin RNAs targeting ITK was constructed and transduced into mice infected with CVB3. ITK-inhibited mice showed reduced cell proliferation (3, 5, and 7 days post-challenge, P<0.05) as well as CD4+ and CD8+ T cells (5 days post-challenge, P<0.05). The altered production of inflammatory cytokines alleviated pathologic heart damage and improved mice survival rate (P<0.05).

CONCLUSION

ITK played an important role in the T cell development and represented a new target for the modulation of T-cell-mediated inflammatory response by CVB3 infection.

Curcumin Protects Mice From Coxsackievirus B3-Induced Myocarditis by Inhibiting the Phosphatidylinositol 3 kinase/Akt/Nuclear Factor-κB Pathway

Viral myocarditis is an inflammation of the myocardium, and coxsackievirus B3 (CVB3) is one of the most important etiologic agents. Curcumin is an active ingredient of Curcumin longa, which has been used as a traditional Chinese herb for the treatment of various inflammatory diseases. The aim of this study was to explore the therapeutic effect of curcumin on CVB3-induced myocarditis and the underlying mechanism. Our results showed that treatment with curcumin could significantly attenuate CVB3-induced myocarditis, as demonstrated by improved weight loss, increased survival rate, reduced serological level cardiac enzymes, and improved heart histopathology. Of importance, curcumin administration was revealed to significantly reduce the systemic and local myocardial expression of proinflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL) 6, and IL-1β, in the CVB3-infected mice. Further study showed that curcumin treatment significantly inhibited the CVB3-induced activation of nuclear factor-κB (NF-κB), a key transcription factor in the pathogenesis of inflammation, in a phosphatidylinositol 3 kinase (PI3K)/Akt pathway-dependent manner. These data indicate that curcumin has protective effect against CVB3-induced myocarditis by inhibiting PI3K/Akt/NF-κB signaling pathway and thus reducing the inflammatory response.

Distinct Th17 inductions contribute to the gender bias in CVB3-induced myocarditis

BACKGROUND

Viral myocarditis is often caused by coxsackievirus B3 (CVB3) infection and occurs more frequently in males. So far, the mechanisms for this sex difference are not fully elucidated. As a new proinflammatory T cell population, Th17 cells are required for the development of CVB3-induced myocarditis, but their impact on the gender bias in viral myocarditis is still unknown.

METHODS

Male and female mice were intraperitoneally infected with CVB3; 7 days later, the frequency of splenic Th17 cells and the expression of associated cytokines and transcriptional factors were compared. Meanwhile, the impact of sex hormones on Th17 cell differentiation post CVB3 infection was also evaluated.

RESULTS

In infected male mice, Th17 cell frequency was remarkably increased and significantly higher than that in female mice. Accordingly, the expression of associated cytokines and transcriptional factors was also obviously augmented in males. When neutralizing interleukin-17 by monoclonal antibody, the male prevalence of myocarditis was obviously abolished, further confirming the effect of Th17 cells on gender bias in viral myocarditis. It was also found that estradiol significantly inhibited the Th17 differentiation post CVB3 infection both in vitro and in vivo. However, testosterone showed no such effects.

CONCLUSIONS

Th17 cells were predominantly induced in CVB3-infected males than females as the inhibitory effect of estrogen on Th17 differentiation and played an important role in the sex differences in the sensitivity to CVB3-induced myocarditis. This study may help us understand the role of Th17 cells in viral myocarditis and facilitate the development of corresponding therapeutic strategies.

Role of monocyte chemoattractant protein-1 (MCP-1) as an immune-diagnostic biomarker in the pathogenesis of chronic periodontal disease

OBJECTIVE

Monocyte chemoattractant protein-1 (MCP-1) is an important chemokine responsible for the initiation, regulation and mobilization of monocytes to the active sites of severe periodontal inflammation. The present study aims at evaluating the levels of MCP-1 in GCF, saliva and serum and to analyze the changes following phase I periodontal therapy. Assessment of possible correlations between levels of MCP-1 in the three biological fluids was also done.

METHODS

Fifteen healthy and 30 patients of severe chronic periodontitis (diseased) participated in the study. Patients of the diseased group underwent scaling/root planing. Evaluation of PI, GI, PD, CAL and collection of samples of GCF, serum and saliva was done at baseline and 6 weeks following periodontal therapy. MCP-1 levels were quantified in all samples using ELISA.

RESULTS

Compared to healthy controls, MCP-1 levels were statistically significantly higher in GCF (p<0.001), saliva (p=0.002) and serum (p<0.001) in subjects with chronic periodontitis. Levels of MCP-1 in all the three fluids decreased significantly in patients after periodontal therapy (p<0.001). There was a significant positive correlation between MCP-1 levels in GCF, saliva and serum in patients of chronic periodontitis both pre (r>0.9) and post-treatment (r>0.6).

CONCLUSIONS

The results suggest that levels of MCP-1 in GCF and saliva can be reliable indicators of severity of periodontal destruction and their serum levels reflect the systemic impact of this local inflammatory disease thereby strengthening the reciprocal oro-systemic association.

Glycyrrhizin administration ameliorates coxsackievirus B3-induced myocarditis in mice

In this study, the authors explored the therapeutic effect of glycyrrhizin (GL) on Coxsackievirus B3 (CVB3)-induced myocarditis and its possible mechanisms involved. The results of this study showed that GL exhibited a profound amelioration of CVB3-induced myocarditis, as evidenced by improved weight loss profile, less increased serological levels of cardiac enzymes, less myocardial inflammation and increased survival rate. Further study showed that this effect was not due to the viral clearance but ascribed to weakened proinflammatory responses, as evidenced by significantly reduced expression of proinflammatory cytokines, including tumor necrosis factor-α, interleukin-1β and interleukin-6. Moreover, the authors demonstrated that GL administration inhibited CVB3-induced nuclear factor-κB activity efficiently by blocking the degradation of nuclear factor -κB inhibitor IκBκ. These data suggest that GL can effectively attenuate the severity of CVB3-induced myocarditis and may present as a new therapeutic approach for the treatment of viral myocarditis.

A20 (TNFAIP3) alleviates CVB3-induced myocarditis via inhibiting NF-κB signaling

Background

Viral myocarditis, which is most prevalently caused by Coxsackievirus B3 (CVB3) infection, is a serious clinical condition characterized by cardiac inflammation. However, efficient therapies targeting inflammation are still lacking and much needed. A20, also known as tumor necrosis factor alpha induced protein 3 (TNFAIP3) is a key negative regulator of inflammation. But whether A20 may affect cardiac inflammation during acute viral myocarditis remains to be elucidated. The aim of this study was to investigate the potential protective effect of A20 on CVB3-induced myocarditis.

Methodology/Principal Findings

Mice were intraperitoneally inoculated with CVB3 to establish acute viral myocarditis model. We found that the expression of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and monocyte chemotactic protein-1 (MCP-1) were markedly and persistently increased during the progression of CVB3-induced myocarditis, and positively correlated with the disease severity. Notably, intravenous injection in vivo with adenovirus expressed A20 (Ad-A20) remarkably reduced CVB3-induced pro-inflammatory cytokines production and alleviated the severity of myocarditis. Further, we observed that nuclear factor-kappaB (NF-κB) signaling which mediates inflammatory response was significantly inhibited in CVB3-infected mice with Ad-A20 treatment. Finally, we revealed that A20 was required to inhibit CVB3-induced NF-κB signaling by restricting TNF receptor associated factor 6 (TRAF6) ubiquitylation.

Conclusion/Significance

This study demonstrates the protective role of A20 against CVB3-induced myocarditis, which may provide a new therapeutic strategy for the treatment of viral myocarditis.

Update on coxsackievirus B3 myocarditis

PURPOSE OF REVIEW

To present recent findings on the pathogenesis of coxsackievirus B3 (CVB3) myocarditis based on animal models, with a focus on the role of T helper (Th) immune responses in disease progression.

RECENT FINDINGS

Acute CVB3 myocarditis is known to be increased by Th1 immune responses, but recent findings indicate that Th1-type immunity protects against acute myocarditis by reducing viral replication and prevents the progression to chronic myocarditis and dilated cardiomyopathy (DCM) by inhibiting Th2 responses. Th2 responses reduce acute myocarditis by inhibiting Th1 responses via regulatory T cells and anti-inflammatory cytokines, but can be deleterious when they induce acute cardiac remodeling leading to chronic myocarditis/DCM. Th2-skewed immune responses allow resistant strains of mice to progress from myocarditis to DCM. In contrast, Th17 responses are elevated during acute and chronic myocarditis and have been found to contribute to cardiac remodeling and DCM.

SUMMARY

Recent data indicate that elevated Th2 and Th17 responses during acute CVB3 myocarditis are critical for the progression from myocarditis to DCM and heart failure because of their ability to induce cardiac remodeling. Th1 responses protect against CVB3 myocarditis by inhibiting Th2 responses and viral replication, but increase acute inflammation.

A truncated analogue of CCL2 mediates anti-fibrotic effects on murine fibroblasts independently of CCR2

The truncated [1+9-76] CCL2 analogue, also known as 7ND, has been described in numerous reports as an anti-inflammatory and anti-fibrotic agent in a wide spectrum of animal models, e.g. models of cardiovascular disease, graft versus host disease and bleomycin-induced pulmonary fibrosis. 7ND has been reported to function as a competitive inhibitor of CCL2 signaling via CCR2 in human in vitro systems. In contrast, the mechanistic basis of 7ND action in animal models has not been previously reported. Here we have studied how 7ND interacts with CCL2 and CCR2 of murine origin. Surprisingly, 7ND was shown to be a weak inhibitor of murine CCL2/CCR2 signaling and displaced murine CCL2 (JE) from the receptor with a K(i)>1 μM. Using surface plasmon resonance, we found that 7ND binds murine CCL2 with a K(d) of 670 nM, which may indicate that 7ND inhibits murine CCL2/CCR2 signaling by a dominant negative mechanism rather than by competitive binding to the CCR2 receptor. In addition we observed that sub-nanomolar levels of 7ND mediate anti-fibrotic effects in CCR2 negative fibroblasts cultured from fibrotic lung of bleomycin-induced mice. Basal levels of extracellular matrix proteins were reduced (collagen type 1 and fibronectin) as well as expression levels of α-smooth muscle actin and CCL2. Our conclusion from these data is that the previously reported effects of 7ND in murine disease models most probably are mediated via mechanisms independent of CCR2.

Safety and immunogenicity of LC16m8, an attenuated smallpox vaccine in vaccinia-naive adults

INTRODUCTION

LC16m8 is an attenuated cell culture-adapted Lister vaccinia smallpox vaccine missing the B5R protein and licensed for use in Japan.

METHODS

We conducted a phase I/II clinical trial that compared the safety and immunogenicity of LC16m8 with Dryvax in vaccinia-naive participants. Adverse events were assessed, as were electrocardiography and laboratory testing for cardiotoxicity and viral culturing of the vaccination sites. Neutralization titers to vaccinia, monkeypox, and variola major were assessed and cell-mediated immune responses were measured by interferon (IFN)-γ enzyme-linked immunosorbent spot and lymphoproliferation assays.

RESULTS

Local and systemic reactions after vaccination with LC16m8 were similar to those reported after Dryvax. No clinically significant abnormalities consistent with cardiac toxicity were seen for either vaccine. Both vaccines achieved antivaccinia, antivariola, and antimonkeypox neutralizing antibody titers >1:40, although the mean plaque reduction neutralization titer of LC16m8 at day 30 after vaccination was significantly lower than Dryvax for anti-NYCBH vaccinia (P < .01), antimonkeypox (P < .001), and antivariola (P < .001). LC16m8 produced robust cellular immune responses that trended higher than Dryvax for lymphoproliferation (P = .06), but lower for IFN-γ ELISPOT (P = .02).

CONCLUSIONS

LC16m8 generates neutralizing antibody titers to multiple poxviruses, including vaccinia, monkeypox, and variola major, and broad T-cell responses, indicating that LC16m8 may have efficacy in protecting individuals from smallpox. Clinical Trials Registration. NCT00103584.

Interactions between the extracellular matrix and inflammation during viral myocarditis

Viral myocarditis is a life-threatening disease characterized by severe cardiac inflammation that can result in heart failure or sudden cardiac death in previously healthy adults. In a subset of patients, it may result in the development of dilated cardiomyopathy due to the chronic inflammatory process. Despite its clinical need, specific treatments for myocarditis are currently not available. The extracellular matrix (ECM) under normal conditions, functions to maintain the mechanical and structural integrity of the heart but can adapt under pathological circumstances to preserve cardiac function. Recent studies have revealed a crucial role of the ECM in the reparative process after cardiac insult, not only as a key component in cardiac remodeling but also as a regulator of the inflammatory process. Increasing our understanding of the impact the ECM has in the disease pathogenesis and progression of viral myocarditis, might lead to much needed therapeutic interventions. In this review we will describe the pathology of viral myocarditis and illustrate the interplay between inflammation and the ECM in general terms, and during viral myocarditis.

Galectin-9 administration ameliorates CVB3 induced myocarditis by promoting the proliferation of regulatory T cells and alternatively activated Th2 cells

In this study we explored the effects of galectin-9 on CVB3 induced myocarditis and its possible mechanisms involved. We demonstrated that galectin-9 expression was significantly up-regulated in the myocardium following CVB3 infection and was correlated with the severity of viral myocarditis. To explore whether galectin-9 may have therapeutic effect on the CVB3 induced myocarditis, galectin-9 was administered daily to mice following CVB3 infection. Significantly reduced CD4(+) T cells and remarkably increased regulatory T cells frequency in the heart tissue were found as compared to the non-treated mice. It was accompanied by a significant decreased level of Th1 cytokines as TNF-α and IFN-γ both in the myocardium and serum, and an increased level of Th2 cytokines such as IL-4 and IL-10. Galectin-9 was further found to promote the proliferation of regulatory T cells and elevated IL-4-secreting Th2 cells. It may represent as a novel therapeutic strategy in treating Th1-mediated inflammatory cardiac disease.