Involvement of Sema4A in the progression of experimental autoimmune myocarditis

Abstract 

Dilated cardiomyopathy often results from autoimmunity triggered by microbial infections during myocarditis. However, it remains unclear how immunological disorders are implicated in pathogenesis of autoimmune myocarditis. Here, we demonstrated that Sema4A, a class IV semaphorin, plays key roles in experimental autoimmune myocarditis (EAM). Dendritic cells pulsed with myosin heavy chain-α peptides induced severe myocarditis in wild-type mice, but not in Sema4A-deficient mice. In adoptive transfer experiments, CD4⁺ T-cells from wild-type mice induced severe myocarditis, while CD4⁺ T-cells from Sema4A-deficient mice exhibited considerably attenuated myocarditis. Our results indicated that Sema4A is critically involved in EAM by regulating differentiation of T-cells.

Abbreviations: DCM, dilated cardiomyopathy, SCID, severe combined immunodeficiency, EAM, experimental autoimmune myocarditis, MyHC-α, myosin α heavy chain, DCs, dendritic cells, IFN-γ, Interferon-γ, T_H1, type 1 helper T-cells, IL, interleukin, Tim-2, T-cell, immunoglobulin and mucin domain protein 2, EAE, experimental autoimmune encephalomyelitis, Treg, regulatory T-cells, Foxp3, forkhead box P3

Keywords: Autoimmune myocarditis, Semaphorin, Dilated cardiomyopathy, Autoimmunity