IL-12 protects against coxsackievirus B3-induced myocarditis by increasing IFN-gamma and macrophage and neutrophil populations in the heart

Th1-type immune responses, mediated by IL-12-induced IFN-gamma, are believed to exacerbate certain autoimmune diseases. We recently found that signaling via IL-12Rbeta1 increases coxsackievirus B3 (CVB3)-induced myocarditis. In this study, we examined the role of IL-12 on the development of CVB3-induced myocarditis using mice deficient in IL-12p35 that lack IL-12p70. We found that IL-12 deficiency did not prevent myocarditis, but viral replication was significantly increased. Although there were no changes in the total percentage of inflammatory cells in IL-12-deficient hearts compared with wild-type BALB/c controls by FACS analysis, macrophage and neutrophil populations were decreased. This decrease corresponded to reduced TNF-alpha and IFN-gamma levels in the heart, suggesting that macrophage and/or neutrophil populations may be a primary source of TNF-alpha and IFN-gamma during acute CVB3 myocarditis. Increased viral replication in IL-12-deficient mice was not mediated by reduced TNFRp55 signaling, because viral replication was unaltered in TNFRp55-deficient mice. However, STAT4 or IFN-gamma deficiency resulted in significantly increased viral replication and significantly reduced TNF-alpha and IFN-gamma levels in the heart, similar to IL-12 deficiency, indicating that the IL-12/STAT4 pathway of IFN-gamma production is important in limiting CVB3 replication. Furthermore, STAT4 or IFN-gamma deficiency also increased chronic CVB3 myocarditis, indicating that therapeutic strategies aimed at reducing Th1-mediated autoimmune diseases may exacerbate common viral infections such as CVB3 and increase chronic inflammatory heart disease.     

黄芪总黄酮对病毒性心肌炎小鼠心律失常与内质网应激因子的影响

目的：研究黄芪总黄酮（TFA）对病毒性心肌炎小鼠心律失常与内质网应激及缝隙连接蛋白作用,明确TFA抗病毒性心肌炎合并心律失常作用机制。方法：36只雄性Balb/c小鼠分为正常对照组、病毒性心肌炎组和TFA组（n=12）,病毒性心肌炎组腹腔内无菌注射含0.1 ml/d 10-950 TCID柯萨奇B3病毒（CVB3）,注射3 d制备Balb/c小鼠病毒性心肌炎模型,TFA组给予CVB3同时尾静脉注射0.1 ml TFA （20 mg/L）,共7 d。实验结束后心电图检测心律失常发生率后处死小鼠,取心脏行HE染色,观察心肌病理改变,Western blot检测各组小鼠心肌细胞葡萄糖调节蛋白78（GRP78）、内质网应激信号通路因子激活转灵因子4（ATF4）及缝隙连接蛋白（Cx43）表达。结果：与正常组比较,病毒性心肌炎组GRP78与ATF4的表达显著升高（P<0.01）,Cx43表达明显下降（P<0.01）;与病毒性心肌炎组比较,TFA组小鼠心肌细胞GRP78与内质网应激信号通路因子ATF4表达明显减少（P<0.01）,Cx43表达明显增多（P<0.01）。结论：TFA抗心律失常作用可能与缓解内质网应激及增加Cx43表达有关。     

In Vivo Delivery of Adenoviral Vector Containing Interleukin-17 Receptor A Reduces Cardiac Remodeling and Improves Myocardial Function in Viral Myocarditis Leading to Dilated Cardiomyopathy

Th17 cells have been implicated in the pathogenesis of myocarditis. Interleukin (IL)-17A produced by Th17 cells is dispensable for viral myocarditis but essential for the progression to dilated cardiomyopathy (DCM). This study investigated whether the adenoviral transfer of the IL-17 receptor A reduces myocardial remodeling and dysfunction in viral myocarditis leading to DCM. In a mouse model of Coxsackievirus B3 (CVB3)-induced chronic myocarditis, the delivery of the adenovirus-containing IL-17 receptor A (Ad-IL17RA:Fc) reduced IL-17A production and decreased the number of Th17 cells in the spleen and heart, leading to the down-regulation of systemic TNF-α and IL-6 production. Cardiac function improved significantly in the Ad-IL17R:Fc- compared with the Ad-null-treated mice 3 months after the first CVB3 infection. Ad-IL17R:Fc reduced the left ventricle dilation and decreased the mortality in viral myocarditis, leading to DCM (56% in the Ad-IL17R:Fc versus 76% in the Ad-null group). The protective effects of Ad-IL17R-Fc on remodeling correlated with the attenuation of myocardial collagen deposition and the reduction of fibroblasts in CVB3-infected hearts, which was accompanied by the down-regulation of A distintegrin and metalloprotease with thrombospondin type 1 motifs (ADAMTS-1), Matrix metalloproteinase-2(MMP-2), and collagen subtypes I and III in the heart. Moreover, in cultured cardiac fibroblasts, IL-17A induced the expression of ADAMTS-1, MMP-2, and collagen subtypes I and III and increased the proliferation of fibroblasts. We determined that the delivery of IL-17-RA:Fc reduces cardiac remodeling, improves function, and decreases mortality in viral myocarditis leading to DCM, possibly by suppressing fibrosis. Therefore, the adenoviral transfer of the IL-17 receptor A may represent an alternative therapy for chronic viral myocarditis and its progression to DCM.     

The in vitro and in vivo antiviral effects of salidroside from Rhodiola rosea L. against coxsackievirus B3

The aim of this study was to investigate the antiviral effects of salidroside, a major component of Rhodiola rosea L. First, the antiviral effects of salidroside against coxsackievirus B3 (CVB3) were determined in vitro and in vivo. Then, the effect of salidroside on the mRNA expression of some important cytokines was measured in hearts of infected BALB/c mice by RT-PCR. Salidroside exhibited obvious antiviral effects both in in vitro and in vivo experiments. Salidroside was found to modulate the mRNA expression of interferon-gamma (IFN-gamma), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-alpha), and interleukin-2 (IL-2). In conclusion, salidroside possesses antiviral activities against CVB3 and it may represent a potential therapeutic agent for viral myocarditis.     

Antiviral and myocyte protective effects of murine interferon-beta and -{alpha}2 in coxsackievirus B3-induced myocarditis and epicarditis in Balb/c mice

The present study tested the hypothesis that murine (m)IFN-beta or mIFN-alpha(2) can eliminate cardiac viral load and protect cardiomyocytes from injury in animals infected with coxsackievirus B3 (CVB3). CVB3-inoculated male Balb/c mice exhibited signs of illness, including lethargy, progressive weight loss, and death (10% on day 3 and 100% on day 8). Cardiac viral load was high [4,277 +/- 1,009 plaque-forming units and 25 +/- 5 copies CVB3/hypoxanthine guanine phosphoribosyl transferase 1 mRNA] on day 4. The cardiac tissue exhibited severe inflammatory infiltration and myocyte damage with an average myocarditis integrated pathology score of 2.1 +/- 0.2 on day 7. Most of the mice infected with CVB3 also developed epicarditis, and 55% had intraventricular thrombi present. Treatment with mIFN-beta [2.5 to 10 million international units (MIU)/kg] dose-dependently improved the general health status in CVB3-inoculated mice, as evidenced by reduction in weight loss, prevention of death, elimination of cardiac viral load, protection of myocytes from injury, decrease in inflammatory cell infiltration, and attenuation of intraventricular thrombus formation. Treatment with 10 MIU/kg mIFN-alpha(2) resulted in a similar level of efficacy as that induced by 5 MIU/kg mIFN-beta, with the exception that mIFN-alpha(2) did not reduce cardiac CVB3 mRNA. However, mIFN-alpha(2) , but not any dose group of mIFN-beta, significantly attenuated CVB3-induced epicarditis. These data demonstrate antiviral effects for both mIFN-beta and mIFN-alpha(2), which lead to protection of the mice from CVB3-induced myocarditis. However, the potential mechanisms leading to a differential host response for the two isoforms of mIFN remain to be elucidated.     

Proteasome inhibition attenuates coxsackievirus-induced myocardial damage in mice

Coxsackievirus B3 (CVB3) is one of the most prevalent pathogens of viral myocarditis, which may persist chronically and progress to dilated cardiomyopathy. We previously demonstrated a critical role of the ubiquitin-proteasome system (UPS) in the regulation of coxsackievirus replication in mouse cardiomyocytes. In the present study, we extend our interest to an in vivo animal model to examine the regulation and role of the UPS in CVB3-induced murine myocarditis. Male myocarditis-susceptible A/J mice at age 4-5 wk were randomized to four groups: sham infection + vehicle (n = 10), sham infection + proteasome inhibitor (n = 10), virus + vehicle (n = 20), and virus + proteasome inhibitor (n = 20). Proteasome inhibitor was administered subcutaneously once a day for 3 days. Mice were killed on day 9 after infection, and infected hearts were harvested for Western blot analysis, plaque assay, immunostaining, and histological examination. We showed that CVB3 infection led to an accumulation of ubiquitin conjugates at 9 days after infection. Protein levels of ubiquitin-activating enzyme E1A/E1B, ubiquitin-conjugating enzyme UBCH7, as well as deubiquitinating enzyme UCHL1 were markedly increased in CVB3-infected mice compared with sham infection. However, there was no significant alteration in proteasome activities at 9 days after infection. Immunohistochemical staining revealed that increased expression of E1A/E1B was mainly localized to virus-damaged cells. Finally, we showed that application of a proteasome inhibitor significantly reduced CVB3-induced myocardial damage. This observation reveals a novel mechanism of coxsackieviral pathogenesis, and suggests that the UPS may be an attractive therapeutic target against coxsackievirus-induced myocarditis.     

雷公藤甲素对病毒性心肌炎细胞凋亡及Fas/FasL 蛋白表达的研究

目的:研究雷公藤甲素对柯萨奇病毒B3病毒(CVB3)感染的病毒性心肌炎小鼠心肌细胞凋亡和Fas/FasL蛋白表达的抑制作用,探讨TP治疗病毒性心肌炎的作用机制。方法:将Balb/c小鼠随机分成4组作为动物模型,分别为对照组、模型组、利巴韦林组和TP组。对照组腹腔注射生理盐水,其余三组腹腔注射CVB3,利巴韦林组和TP组小鼠分别予以相应的药物治疗后,测定各组小鼠存活率及心肌病变积分,采用末端转移酶标记技术(TUNEL法)检测小鼠心肌细胞凋亡,免疫组化法检测Fas/FasL蛋白阳性表达。结果:空白对照组心肌无病变,利巴韦林组、TP组与模型组相比有显著性差异(P<0.01)。正常组鲜见心肌细胞凋亡,模型组细胞凋亡率较正常组显著增加(P<0.01),治疗组利巴韦林组和TP组凋亡率比模型组明显降低(P<0.05,P<0.01)。模型组Fas/FasL表达比正常组显著增多(P<0.01),治疗组利巴韦林组和TP组较模型组显著降低(P<0.01)。结论:雷公藤甲素具有通过抑制Fas/FasL蛋白的表达,减缓心肌细胞凋亡,达到抑制病毒性心肌炎从而保护心肌细胞的作用。     

Coxsackievirus group B type 3 infection upregulates expression of monocyte chemoattractant protein 1 in cardiac myocytes, which leads to enhanced migration of mononuclear cells in viral myocarditis

Coxsackievirus group B type 3 (CVB3) is an important cause of viral myocarditis. The infiltration of mononuclear cells into the myocardial tissue is one of the key events in viral myocarditis. Immediately after CVB3 infects the heart, the expression of chemokine(s) by infected myocardial cells may be the first trigger for inflammatory infiltration and immune response. However, it is unknown whether CVB3 can induce the chemokine expression in cardiac myocytes. Monocyte chemoattractant protein 1 (MCP-1) is a potent chemokine that stimulates the migration of mononuclear cells. The objective of the present study was to investigate the effect of CVB3 infection on MCP-1 expression in murine cardiac myocytes and the role of MCP-1 in migration of mononuclear cells in viral myocarditis. Our results showed that the expression of MCP-1 was significantly increased in cardiac myocytes after wild-type CVB3 infection in a time- and dose-dependent manner, which resulted in enhanced migration of mononuclear cells in mice with viral myocarditis. The migration of mononuclear cells was partially abolished by antibodies specific for MCP-1 in vivo and in vitro. Administration of anti-MCP-1 antibody prevented infiltration of mononuclear cells bearing the MCP-1 receptor CCR2 in mice with viral myocarditis. Infection by UV-irradiated CVB3 induced rapid and transient expression of MCP-1 in cardiac myocytes. In conclusion, our results indicate that CVB3 infection stimulates the expression of MCP-1 in myocardial cells, which subsequently leads to migration of mononuclear cells in 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.     

Antiviral effects of sophoridine against coxsackievirus B3 and its pharmacokinetics in rats

Coxsackievirus B3 (CVB3) is a major pathogen for acute and chronic viral myocarditis. The aim of this study was to investigate the antiviral effects of sophoridine, an alkaloid extracted from Chinese medicinal herb, Sophora flavescens, against CVB3, and the underlying pharmacokinetics. First, we determined the antiviral effects of sophoridine against CVB3 in in vitro (primarily cultured myocardial cells), in vivo (BALB/c mice) and serum pharmacological experiments. Then, we determined the pharmacokinetic behavior in serum samples of SD rats after oral administration by HPLC. Finally, we determined the effects of sophoridine on the production of cytokines in a murine viral myocarditis model by measuring mRNA expression of some important cytokines in hearts of infected BALB/c mice by RT-PCR. We found that sophoridine exhibited obvious antiviral effects both in vitro and in vivo, and serum samples obtained from rats with oral administration of sophoridine reduced the virus titers in infected myocardial cells. The serum concentration profile correlated closely with antiviral activity profile. Moreover, sophoridine significantly enhanced mRNA expression of IL-10 and IFN-gamma, but decreased TNF-alpha mRNA expression. In conclusion, sophoridine possesses antiviral activities against CVB3, by regulating cytokine expression, and it is likely that sophoridine itself, not its metabolites, is mainly responsible for the antiviral activities. Therefore, sophoridine may represent a potential therapeutic agent for viral myocarditis.     

The tyrosine kinase p56lck is essential in coxsackievirus B3-mediated heart disease

Infections are thought to be important in the pathogenesis of many heart diseases. Coxsackievirus B3 (CVB3) has been linked to chronic dilated cardiomyopathy, a common cause of progressive heart disease, heart failure and sudden death. We show here that the sarcoma (Src) family kinase Lck (p56lck) is required for efficient CVB3 replication in T-cell lines and for viral replication and persistence in vivo. Whereas infection of wild-type mice with human pathogenic CVB3 caused acute and very severe myocarditis, meningitis, hepatitis, pancreatitis and dilated cardiomyopathy, mice lacking the p56lck gene were completely protected from CVB3-induced acute pathogenicity and chronic heart disease. These data identify a previously unknown function of Src family kinases and indicate that p56lck is the essential host factor that controls the replication and pathogenicity of CVB3.     

Quantitative trait locus analysis, pathway analysis, and consomic mapping show genetic variants of Tnni3k, Fpgt, or H28 control susceptibility to viral myocarditis

Coxsackievirus B3 (CVB3) infection is the most common cause of viral myocarditis. The pathogenesis of viral myocarditis is strongly controlled by host genetic factors. Although certain indispensable components of immunity have been identified, the genes and pathways underlying natural variation between individuals remain unclear. Previously, we isolated the viral myocarditis susceptibility 1 (Vms1) locus on chromosome 3, which influences pathogenesis. We hypothesized that confirmation and further study of Vms1 controlling CVB3-mediated pathology, combined with pathway analysis and consomic mapping approaches, would elucidate both pathological and protective mechanisms accounting for natural variation in response to CVB3 infection. Vms1 was originally mapped to chromosome 3 using a segregating cross between susceptible A/J and resistant B10.A mice. To validate Vms1, C57BL/6J-Chr 3(A)/NaJ (a chromosome substitution strain that carries a diploid A/J chromosome 3) were used to replicate susceptibility compared with resistant C57BL/6J (B6). A second segregating F2 cross was generated between these, confirming both the localization and effects of Vms1. Microarray analysis of the four strains (A/J, B10.A, C57BL/6J, and C57BL/6J-Chr 3(A)/NaJ) illuminated a core program of response to CVB3 in all strains that is comprised mainly of IFN-stimulated genes. Microarray analysis also revealed strain-specific differential expression programs and genes that may be prognostic or diagnostic of susceptibility to CVB3 infection. A combination of analyses revealed very strong evidence for the existence and location of Vms1. Differentially expressed pathways were identified by microarray, and candidate gene analysis revealed Fpgt, H28, and Tnni3k as likely candidates for Vms1.     

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-β in the early viremic phase. TRIF(-/-) myocytes displayed a TLR4-dependent suppression of IFN-β, and pharmacological treatment of CVB3-infected TRIF(-/-) mice with murine IFN-β 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.     

Involvement of natural killer cells in coxsackievirus B3-induced murine myocarditis

The role of natural killer cells in the temporal development of coxsackievirus B3-induced myocarditis in adolescent CD-1 male mice was examined. Inoculation of purified CVB3m induced maximum NK cell activity in the splenic populations at 3 days postinoculation (p.i.) as assessed by lysis of YAC-1 cells; maximum virus titers in heart tissues were also found at day 3 p.i. Mice depleted of NK cells after injection of anti-asialo GM1 antiserum i.v. had decreased NK cell activity, increased CVB3m titers in heart tissues, and exacerbated myocarditis. Although lesion number was not increased in heart tissues of the latter mice, lesions in these mice exhibited increased myocyte degeneration and dystrophic calcification above that found in lesions of mice inoculated with CVB3m only. No alteration in interferon titers were observed in CVB3m-infected mice treated with anti-asialo GM1 antiserum as compared with normal CVB3m-infected mice. Measurements of splenic NK cell activity in mice inoculated with doses of 10(2) to 10(8) PFU of CVB3m per mouse or UV-irradiated virus suggest that replication of CVB3m is required for NK cell activation. An amyocarditic variant of CVB3m (ts5R) was shown to replicate in heart tissues and to elicit NK cell activity comparable to that elicited by CVB3m. Therefore, the data suggest that NK cell activation depends on virus replication and that these cells provide some protection against CVB3m-induced myocarditis by limiting virus replication in heart tissues.     

Coxsackievirus-induced myocarditis in mice: a model of autoimmune disease for studying immunotoxicity

Excellent animal models are available for virus-induced and autoimmune heart disease that are remarkably similar to human disease. Developing good animal models for heart disease is crucial because cardiovascular disease is now the leading cause of death in the United States and is estimated to be the leading cause of death in the world by the year 2020. A significant proportion of heart disease in Western populations is associated with inflammation. Myocarditis, or inflammation of the heart muscle, is the major cause of sudden death in young adults. Although most individuals recover from acute myocarditis, genetically susceptible individuals may go on to develop chronic myocarditis and dilated cardiomyopathy (DCM) resulting in congestive heart failure. In this article, we describe a model of autoimmune myocarditis and DCM induced by inoculation with heart-passaged coxsackievirus B3 (CVB3). Intraperitoneal inoculation of susceptible mice with CVB3 induces acute cardiac inflammation from days 7 to 14 postinfection (pi) that progresses to chronic myocarditis and DCM from day 28 to at least 56 pi. The model of CVB3-induced myocarditis presented here allows dissection of the contribution of viral infection and xenobiotics on immune dysregulation and inflammation in the heart. An improved understanding of the interaction between environmental exposures and the development of heart disease represents a clear challenge for immunotoxicologists.     

Truncated monocyte chemoattractant protein‐1 can alleviate cardiac injury in mice with viral myocarditis via infiltration of mononuclear cells

BALB/c mice inoculated intraperitoneally with coxsackievirus group B type 3 (CVB3) were allocated to five groups; namely, a viral myocarditis group infected with CVB3 alone (control group), an antibody intervention group that received intracardiac anti‐MCP‐1, an antibody intervention control group that received goat IgG, a tMCP‐1 intervention group that received plasmid pVMt expressing tMCP‐1, and a tMCP‐1 intervention control group that received plasmid pVAX1. There was also a normal control group. The ratio of murine heart weight to body weight, pathological score of myocardial tissue, serum creatine kinase‐MB titers and CVB3 loading of myocardial tissue were assessed. The cardiac lesions in mice that received 20, 40 or 60 µg pVMt (P < 0.05) were less severe than those in control mice with untreated viral myocarditis. In addition, fewer mononuclear cells had infiltrated the myocardium of mice who received 40 or 60 µg pVMt intramyocardially (P < 0.01), whereas there was no difference in mononuclear cell infiltration between mice with viral myocarditis and those that received 20 µg pVMt (P > 0.05). There was also no difference between mice that received anti‐MCP‐1 antibody and those that received 40 µg pVMt in ratio of HW/BW, serum CK‐MB titers and pathological score (P > 0.05). This study showed that tMCP‐1 can alleviate cardiac lesions and cardiac injury in mice with viral myocarditis via infiltration of mononuclear cells. Thus, tMCP‐1 may be an alternative to anti‐MCP‐1 antibody treatment of viral myocarditis. Further research is required.     

桂皮醛对小鼠柯萨奇病毒诱发病毒性心肌炎的作用(英文)

已知Toll样受体4(Toll-like receptors 4,TLR4)及其下游信号组分在柯萨奇病毒(CoxsackievirusB,CVB)诱发的病毒性心肌炎中扮演重要的角色,其在治疗中的作用仍不明确。桂皮醛具有抗病毒以及成剂量依赖性抑制由TLR4诱导的核因子活性的作用,而其对病毒性心肌炎的作用机制尚不明确。我们的实验结果显示:在体外,桂皮醛对正常心肌细胞的IC50为15μM;100-1000μM桂皮醛能显著抑制心肌细胞中的病毒滴度(P0.01),而细胞存活率与CVB组无统计学差异(P0.01)。而在病毒性心肌炎小鼠体内,与模型组比较,20和40mg/kg桂皮醛i.p.使第7 d血清中NO的含量以及心肌中诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS),肿瘤坏死因子(tumor necrosis factor,TNF-α),核因子κB P65(nuclear factor-κB P65,NF-κB P65)和TLR4蛋白质表达显著降低(P0.05)。降低第21 d心脏体重比(Heat Weight/Body Weight,Hw/Bw)比值,提高小鼠生存率,减轻病理损伤的作用。这些结果显示桂皮醛虽在体外无抗病毒活性,但其在体内具有降低病毒滴度和抑制TLR-4-NF-κB信号传导的作用,对病毒性心肌炎小鼠具有治疗作用。桂皮醛可能通过对TLR-4-NF-κB信号传导抑制作用,作为一种新的方法治疗病毒性心肌炎。     

Using IFN-γ as a Biomarker for Detecting Exposure to Viral Pathogens

To determine whether interferon gamma (IFN-γ) can be used as a biomarker of exposure to viral pathogens, 12-week-old BALB/c mice were injected intraperitoneally with coxsackievirus B3 (CVB3) or coxsackievirus B4 (CVB4) diluted in sterilized phosphate-buffered saline (PBS). Control mice were injected with PBS only. Four months after viral infection, mouse spleen cells were harvested and assayed for the release of IFN-γ by memory T cells after in vitro stimulation with viral antigens, phytohemagglutinin (PHA), and PBS, respectively. The level of IFN-γ was examined by an antibody-capture enzyme-linked immunosorbent assay (ELISA). A marked increase in the level of IFN-γ was observed when memory T cells from CVB3-infected mice were incubated with CVB3 virus, but not with CVB4 or PBS. Conversely, memory T cells from mice infected by CVB4 were not stimulated to produce IFN-γ when they were incubated with CVB3 and PBS, but did significantly produce IFN-γ when stimulated with CVB4. T cells from mice injected with PBS did not release IFN-γ after stimulation with CVB3 or CVB4. However, these T cells did release IFN-γ after stimulation with PHA. Our results demonstrated that IFN-γ produced by memory T cells is virus-specific and may have use as a biomarker in viral exposure studies. The results of this study may be extended to the study of infection by pathogens that are capable of inducing cell-mediated immune response in humans. Disclaimer: The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here. It has been subjected to Agency’s administrative review and approved for publication.     

Direct gene transfer with IP-10 mutant ameliorates mouse CVB3-induced myocarditis by blunting Th1 immune responses

Background

Myocarditis is an inflammation of the myocardium that often follows the enterovirus infections, with coxsackievirus B3 (CVB3) being the most dominant etiologic agent. We and other groups previously reported that chemokine IP-10 was significantly induced in the heart tissue of CVB3-infected mice and contributed to the migration of massive inflammatory cells into the myocardium, which represents one of the most important mechanisms of viral myocarditis. To evaluate the direct effect of IP-10 on the inflammatory responses in CVB3 myocarditis, herein an IP-10 mutant deprived of chemo-attractant function was introduced into mice to antagonize the endogenous IP-10 activity, and its therapeutic effect on CVB3-induced myocarditis was evaluated.

Methodology/Principal Findings

The depletion mutant pIP-10-AT, with an additional methionine after removal of the 5 N-terminal amino acids, was genetically constructed and intramuscularly injected into BALB/c mice after CVB3 infection. Compared with vector or no treatment, pIP-10-AT treatment had significantly reduced heart/body weight ratio and serum CK-MB level, increased survival rate and improved heart histopathology, suggesting an ameliorated myocarditis. This therapeutic effect was not attributable to an enhanced viral clearance, but to a blunted Th1 immune response, as evidenced by significantly decreased splenic CD4⁺/CD8⁺IFN-γ⁺ T cell percentages and reduced myocardial Th1 cytokine levels.

Conclusion/Significance

Our findings constitute the first preclinical data indicating that interfering in vivo IP-10 activity could ameliorate CVB3 induced myocarditis. This strategy may represent as a new therapeutic approach in treating viral myocarditis.     

Blockade of interleukin-17A protects against coxsackievirus B3-induced myocarditis by increasing COX-2/PGE2 production in the heart

The Th17/interleukin (IL)-17 axis controls inflammation and might be important in the pathogenesis of experimental autoimmune myocarditis (EAM) and other autoimmune diseases. However, the mechanism underlying the increased Th17 cell response in coxsackievirus-induced myocarditis remains unclear. This study aimed to elucidate the regulatory mechanisms affected by blocking IL-17A responses in acute virus-induced myocarditis (AVMC) mice. The results showed that IL-17A and COX-2 proteins were significantly increased in the cardiac tissue of acute myocarditis, as were Th17 cells in the spleen. Using anti-mouse IL-17Ab to block IL-17A on day 7 of the viral myocarditis led to decreased expressions of cardiac tumor-necrosis factor alpha, IL-17A and transforming growth factor beta in AVMC mice compared to isotype control mice. COX-2 and prostaglandin E2 proteins were dramatically elevated, followed by marked reductions in CVB3 replication and myocardial injury. These results hint that the Th17/IL-17 axis is intimately associated with viral replication in acute myocarditis via induction of COX-2 and prostaglandin E2.