AIM2 Co-immunization with VP1 Is Associated with Increased Memory CD8 T Cells and Mounts Long Lasting Protection against Coxsackievirus B3 Challenge.

The recurrent Coxsackievirus B3 (CVB3) infection is the most important cause of intractable myocarditis which often leads to chronic myocarditis and even dilated cardiomyopathy. Therefore, enhanced DNA vaccines capable of memory CD8 T cells are essential for long-lasting immunological protection against CVB3 infection. In this study, absent in melanoma 2 (AIM2) was used as an adjuvant to enhance the induction of memory CD8 T cells elicited by VP1 (viral capsid protein 1) vaccine. Mice were intramuscularly injected with 50 µg AIM2 plasmid and equal amount of VP1 plasmid (pAIM2/pVP1) vaccine 4 times at 2 week-intervals. We observed that the protection of pAIM2/pVP1 vaccine against CVB3 challenge was evidenced by significantly improved cardiac function, reduced myocardial injuries, and increased survival rate when compared with immunization with pVP1. Co-immunization with pAIM2/pVP1 robustly augmented T lymphocytes proliferation and CVB3-specific cytotoxic T lymphocyte responses. Importantly, 16 weeks after the last immunization, pAIM2/pVP1 co-immunization significantly enhanced the expression of Bcl-6, SOCS3, and Sca-1 which are critical for memory CD8 T cells as compared with pVP1 immunization. Notably, CD8 T cells that are likely vaccine-induced memory T cells were responsible for the protective efficacy of pAIM2/pVP1 vaccine by abolition of a CD8 T cell immune response following a lethal dose of CVB3 infection. Our results indicate that AIM2-adjuvanted vaccine could be a potential and promising approach to promote a long-lasting protection against CVB3-induced myocarditis.

Green Tea Polyphenol Epigallocatechin-3-gallate-Alleviated Coxsackievirus B3-induced Myocarditis Through Inhibiting Viral Replication but Not Through Inhibiting Inflammatory Responses.

Viral myocarditis, which is mainly caused by coxsackievirus B3 (CVB3), affects about 5%-20% of the world population and still lacks efficient treatments. Green tea, a tonic and healthful beverage that was originated in ancient China, has been receiving considerable attention for its protective effect on cardiovascular diseases in recent years. In the present investigation, we aimed to explore the effect of green tea polyphenol epigallocatechin-3-gallate (EGCG) on CVB3-induced myocarditis and its underlying mechanism. Our study showed that EGCG could alleviate CVB3-induced myocarditis as evidenced by less cardiac injury and higher survival rate. Furthermore, we found that EGCG failed to downregulate the expression of inflammatory cytokines but could significantly inhibit the replication of CVB3. Furthermore, we found that EGCG treatment could downregulate the protein expression level of coxsackievirus and adenovirus receptor, the major receptor for CVB3 to infect cardiac myocytes. In conclusion, our data indicated that EGCG could ameliorate CVB3-induced myocarditis through inhibiting viral replication, which might provide a potential novel therapeutic strategy for viral myocarditis.

Remission of CVB3-induced myocarditis with Astragaloside IV treatment requires A20 (TNFAIP3) up-regulation.

Viral myocarditis (VMC) most prevalently caused by coxsackievirus B3 (CVB3) infection is characterized by severe cardiac inflammation. Therapeutic options for the disease are still limited. Astragaloside IV (AST-IV), a purified small molecular saponin (C41 H68 O14 , MW 784), is the main active component of Chinese medical herb Astragalus which has been empirically prescribed for the treatment of heart dysfunction for centuries. In this study, we investigated the effect of AST-IV on CVB3-induced myocarditis and explored its possible mechanism involved. The results showed that AST-IV administration alleviated the severity of myocarditis and attenuated cardiac inflammation, which was mediated by inhibition of nuclear factor-kappaB (NF-κB) signalling. Importantly, we further identified that the inhibitory effect of AST-IV on NF-κB signalling was through increasing A20 (TNFAIP3) expression. Moreover, we validated that A20 was critical for the therapeutic efficacy of AST-IV on CVB3-induced myocarditis. Finally, we revealed that AST-IV enhanced A20 expression at post-transcriptional level by stabilization of mRNA. Our findings uncover a previously unknown mechanism for AST-IV in the treatment of VMC because of modulating inflammatory response via increasing A20 expression, which provide a potential target for screening new drugs and are helpful for optimization of the therapeutic strategies for VMC.

Disease association and arthritogenic potential of circulating antibodies against the α1,4-polygalacturonic acid moiety.

Much progress has been made in recent years on the diagnostic value, Ag specificity, and pathogenic roles of autoantibodies correlated to the development of rheumatoid arthritis (RA) in humans. However, carbohydrate Ag-specific autoantibodies that may also play important roles in RA have largely been ignored. In this article, we report that serum levels of Abs capable of recognizing α1,4-polygalacturonic acid [(PGA); major structural component of pectin] strongly correlate with RA in humans. The measurements of PGA-specific Abs (PGA-Abs) in sera are comparable to rheumatoid factors and anti-cyclic citrullinated peptide Abs as serological diagnostic markers for RA in terms of sensitivity and specificity. Immunohistochemical staining results indicate that the PGA-Abs selectively bound synovial membrane cells and chondrocytes in the joints of both humans and rabbits (but not rodents). Induction of PGA-Abs by s.c. immunization of rabbits with carrier protein-conjugated synthetic PGA led to severe inflammatory reactions (synovial hyperplasia, small vessel proliferation, and inflammatory cell infiltration) in the joints. Injection of affinity purified anti-PGA IgG into the synovial cavity of rabbits resulted in accumulation of proinflammatory cytokines such as TNF-α, IL-8, and IL-1ß in synovial fluid, as well as local pathological damage. We conclude that the PGA-cross-reactive moiety represents a major autoantigen in the joints and can be targeted by autoantibodies capable of triggering arthritogenic responses in vivo.

Kushen flavonoids induce apoptosis in tumor cells by inhibition of NF-kappaB activation and multiple receptor tyrosine kinase activities.

In this report, the mechanism of the antitumor activities of Kushen flavonoids (KS-Fs) were explored. KS-Fs and kurarinone (Kur), a single flavonoid compound, were able to induce apoptosis of H460 and Eca-109 cells in vitro and H460 cells in vivo. The apoptosis inducing effect was enhanced in the presence of Taxol. In H460 xenograft mice treated with Kur, down-regulation of Bcl-2 and up-regulation of caspase 8 and caspase 3 in tumors were observed by immunohistochemical staining. In addition, KS-Fs and Kur were able to inhibit TNFalpha-induced NF-kappaB activation in 293 cells mediated by the decreased IkappaBalpha phosphorylation. Further the effects of KS-Fs and Kur on multiple receptor tyrosine kinase activities were explored. In cell-based assays, KS-Fs and Kur inhibited the EGF-induced EGF receptor phosphorylation in A431 cells and a constitutively activated Her-2 in MDA-MB-453s cells. In enzymatic assays, KS-Fs and Kur inhibited KDR, but not PDGF BR activities. In A431 xenograft mice treated with Kur, an inhibition of EGF receptor phosphorylation in tumors was observed. These results reveal a novel mechanism by which KS-Fs induces apoptosis in tumors by acting on multiple cellular targets including the inhibition of NF-kappaB activation and multiple receptor tyrosine kinase activities.

Novel antitumor activities of Kushen flavonoids in vitro and in vivo.

Kushen (KS), the dried roots of Sophora flavescens Aiton, has a long history of use in traditional Chinese medicine to treat inflammatory diseases and cancer. Kushen alkaloids (KS-As) and Kushen flavonoids (KS-Fs) are the well characterized components in KS. KS-As have been considered biologically active and developed in China as anticancer drugs. In an effort to screen novel antitumor agents from botanicals, more potent antitumor activities were identified in KS-Fs than in KS-As. KS-Fs were able to inhibit the growth of a panel of tumor cell lines and enhanced the antitumor activities of Taxol in vitro. The antitumor activities of KS-Fs and Kur, a single KS-Fs compound, were demonstrated in murine and xenograft human tumor models. Further, it was shown that KS-Fs and Kur were able to enhance the effect of Taxol to inhibit the growth of H460 and Eca-109 xenograft tumors. In addition, peripheral blood cell counts were not significantly affected in normal mice treated with KS-Fs at 200 mg/kg/day for 2 weeks. These results suggest that KS-Fs may be developed as novel antitumor agents and that the currently marketed KS-As drugs in China may have missed the major antitumor activities in Kushen.

All-trans retinoic acid biases immune response induced by DNA vaccine in a Th2 direction.

Vitamin A deficiency diminishes Th2-mediated Ab responses. Providing Vitamin A or its active metabolites reverses this defect. All-trans retinoic acid (ATRA), an acid derivation of Vitamin A, regulates the balance of immune response induced by TR421-hCGbeta DNA vaccine. Compared to DNA vaccine alone or treatment with vehicle, significantly higher level of antibody against the protein encoded by DNA vaccine was observed in mice 6 weeks after the first immunization. The IgG2a/IgG1 ratio was lower in mice treated with ATRA. We also found that treatment with ATRA also diminishes specific cellular immune response induced by gene immunization by measuring the marker of cellular immune response. We conclude that ATRA biases the immune response to Th2 direction induced by DNA vaccine and acts as a candidate adjuvant and immunomodulatory molecule.