A striking common O-linked N-acetylglucosaminyl moiety between cruzipain and myosin

D.M. ACOSTA; L.L. SOPRANO; M.R. FERRERO; M.LANDONI; M.I. ESTEVA; A.S. COUTO; V.G. DUSCHAK

Córdoba-Argentina

Simposio; XXIV REUNION Científica ANUAL SOC. ARG.de Protozoología; 2010

SOC. ARG.de Protozoología

O-linked N-acetylglucosaminyl moieties (O-GlcNAc) constitute an abundant, dynamic reversible and regulatory post translational modification of serine/threonine residues for numerous cytoplasmic and nuclear proteins. We have previously demonstrated the presence of single units of O-linked N-acetylglucosamine (GlcNAc), in the C-Terminal domain of cruzipain (Cz), a lysosomal major antigen from Trypanosoma cruzi. In addition, antibodies directed against some self-antigens like myosin are associated with Chagas heart disease.     Herein, to evaluate the molecular involvement of O-linked N-acetyl-glucosamine (GlcNAc) moiety present in the major cysteine protease of the pathogen T. cruzi, both in Cz recognition as well as in the cross-reactivity between Cz and myosin molecules, rabbit cardiac myosin and sera from mice immunized with the complete molecule and with its C-terminal domain were used as tools. Rabbit preimmune, polyclonal sera specific for anti-recTc13 and for anti-microsomal and anti-flagellar fractions were used as negative or positive controls, respectively. In addition, rabbit sera specific to cruzipain and C-T were also used to test heterologous cross-reactivity on heart tissue of immunized mice by immunogold electron microscopy.         The participation of O-GlcNAc moieties in the molecular antigenicity of Cz was demonstrated using growing amounts of GlcNAc linked to aprotinin by ELISA. The immune cross-reactivity between cruzipain and myosin is mainly focused in the C-T domain. ELISA inhibition assays using rabbit sera specific for Cz and/or C-T in conjunction with immunogold electronmicroscopy analysis of heart tissues from mice immunized with Cz and C-T confronted with polyclonal rabbit sera specific for Cz and C-T prior and after myosin adsorption, evidenced that O-GlcNAc moieties constitute a common epitope between cruzipain and either myosin or other cardiac O-GlcNAc-containing proteins. These results provide a new insight into the molecular immunopathogenesis of Chagas heart disease.