High-mobility group box 1 (HMGB1), a non-histone nuclear protein, has been implicated in cardiovascular diseases. Dilated cardiomyopathy (DCM), one of the leading causes of heart failure, is often caused by coxsackievirus B3-triggered myocarditis and promoted by the post-infectious autoimmune process. Th17 cells, a novel CD4 1 T subset, may be important in the pathogenesis of autoimmune myocarditis. In the present study, we attempted to block HMGB1 function with a monoclonal antibody specific for HMGB1 B box and investigated the effects of the blockade on Th17 cells and experimental autoimmune myocarditis (EAM). After induction of EAM, HMGB1 protein levels were significantly elevated both in the heart and blood. Administration of an anti-HMGB1 B box mAb attenuated cardiac pathological changes and reduced the number of infiltrating inflammatory cells in the heart during EAM. These protective effects of HMGB1 blockade correlated with a reduced number of Th17 cells in local tissues and lower levels of IL-17 in the serum. Furthermore, in vitro, studies demonstrated that HMGB1 promoted Th17-cell expansion. Therefore, we speculate that HMGB1 blockade ameliorates cardiac pathological changes in EAM by suppressing Th17 cells.Key words: Dilated cardiomyopathy . Experimental myocarditis . HMGB1 . Th17 cells IntroductionHigh-mobility group box 1 (HMGB1), a non-histone nuclear protein, has been functionally characterized as an alarmin or damage-associated molecular pattern (DAMP) [1,2]. It is constitutively expressed in quiescent cells and stored in the nucleus [3]. HMGB1 is one of the most evolutionarily conserved proteins in eukaryotes, with 100% identity between mice and rats, and 99% identity between rodents and humans [3].HMGB1 has been shown to be involved in both infectious and non-infectious inflammatory disease [2,4]. HMGB1 is released into the extracellular milieu during cell apoptosis/death [5], and by macrophages and monocytes in response to cellular stress or injury [6]. HMGB1 binds to the endogenous receptor for advanced glycation endproducts [7], exogenous toll-like receptor 2/4/9 (TLR2/4/9) [8,9], and CD24/Siglec-10 [10], and induces the expression of proinammatory cytokines, chemokines, and adhesion molecules [3,6]. Although, HMGB1 was initially 3586thought to be a late mediator of sepsis, recent data also indicated that HMGB1 is associated with many other pathological conditions, such as autoimmune disease [11], cancer [12][13][14], trauma, ischemia-reperfusion injury [15,16], tissue repair and regeneration [17,18], and cardiovascular diseases [19]. Furthermore, HMGB1 has restorative effects on CD4 1 T-helper cell modulation [20].Dilated cardiomyopathy (DCM) is one of the leading causes of severe heart failure and the most common indication for heart transplantation. DCM is often caused by coxsackievirus B3-triggered myocarditis [21]. Experimental autoimmune myocarditis (EAM) is a mouse model of postinfectious myocarditis, characterized by inflammatory infiltration of the myocardium and cardiac myocyte ne...

Myocarditis is a common clinical cardiovascular disease, and some patients progress to dilated cardiomyopathy (DCM) with chronic heart failure. Common viral infections are the most frequent cause of myocarditis, but other pathogens and autoimmune diseases have also been implicated. T(h)17 cells are novel IL-17-producing effector T helper cells that play an important role in the development of autoimmune myocarditis. Furthermore, IL-17 is also important in post-myocarditis cardiac remodeling and progression to DCM. However, the mechanisms whereby IL-17 and IL-17-producing cells promote the progression of cardiac fibrosis remain unclear. We therefore investigated whether IL-17 directly induced cardiac fibrosis in experimental autoimmune myocarditis (EAM) and explored the possible molecular mechanisms. The EAM model was induced and serum IL-17 level was detected by ELISA; western blot, immunofluorescence and sirius red staining were used to analyze the collagen expression. PCR was used to assay the IL-17RA and IL-17RC. The results indicated that IL-17 induced cardiac fibrosis both in vitro and in vivo. The protein kinase C (PKC)β/Erk1/2/NF-κB (Nuclear Factor κappa B) pathway was involved in the development of myocardial fibrosis and IL-17 contributed to cardiac fibrosis following EAM via this pathway. These results provide the first direct evidence for the involvement of the PKCβ/Erk1/2/NF-κB signaling pathway in IL-17-induced myocardial fibrosis.

Herbaspirillum species, colonized the plant rhizosphere, also called rhizobacteria, are plant growth-promoting bacteria. Recently we isolated Herbaspirillum from blood cultures of acute lymphoblastic leukemia (ALL) and identified by PCR and gene sequencing. Herbaspirillum may be a potential pathogenic bacteria. Although the exact role that these species play in ALL patients is unknown, their differentiation from other species has serious implications for clinical care and patient well-being.

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Enterovirus 71 (EV71) affects the health of young children globally causing severe neurologic diseases. The relationship between EV71 infection and T helper type 17 (Th17) has not been described, although this new Th subset or interleukin-17 (IL-17) has been reported to be associated with other viral infections. The purpose of the current study was to describe the immune profile involving Th17 cells, neutrophils, and related factors and to speculate on the possible immunopathogenesis of EV71 infections. Flow cytometry and an automatic blood cell counter were used to analyze circulating Th17 cells and count neutrophils, respectively. Expression of acid-related orphan nuclear receptor gamma t (ROR γt) was evaluated by reverse-transcriptional PCR, and enzyme linked immunosorbent assays (ELISAs) were used for detecting concentrations of IL-17, IL-23, and IFN-γ. The results showed that the frequencies of Th17 cells (1.47 ± 0.87%) and the number of neutrophils (7.4 ± 4.1 × 10(9) /L) in peripheral blood samples from children infected with EV71 were significantly higher compared to controls. In addition, there was a statistically higher expression of ROR γt in peripheral blood mononuclear cells (PBMCs) and elevated concentrations of IL-17 and IL-23 in sera, but lower IFN-γ production during EV71 infections. The findings suggest that Th17 cells are mediators during the immunologic process.