Phospholipase A1: A novel virulence factor in Trypanosoma cruzi

Phospholipase A(1) (PLA(1)) has been described in the infective stages of Trypanosoma cruzi as a membrane-bound/secreted enzyme that significantly modified host cell lipid profile with generation of second lipid messengers and concomitant activation of protein kinase C. In the present work we determined higher levels of PLA(1) expression in the infective amastigotes and trypomastigotes than in the non-infective epimastigotes of lethal RA strain. In addition, we found similar expression patterns but distinct PLA(1) activity levels in bloodstream trypomastigotes from Cvd and RA (lethal) and K98 (non-lethal) T. cruzi strains, obtained at their corresponding parasitemia peaks. This fact was likely due to the presence of different levels of anti-T. cruzi PLA(1) antibodies in sera of infected mice, that modulated the enzyme activity. Moreover, these antibodies significantly reduced in vitro parasite invasion indicating the participation of T. cruzi PLA(1) in the early events of parasite-host cell interaction. We also demonstrated the presence of lysophospholipase activity in live infective stages that could account for self-protection against the toxic lysophospholipids generated by T. cruzi PLA(1) action. At the genome level, we identified at least eight putative genes that codify for T. cruzi PLA(1) with high amino acid sequence variability in their amino and carboxy-terminal regions; a putative PLA(1) selected gene was cloned and expressed as a recombinant protein that possessed PLA(1) activity. Collectively, the results presented here point out at T. cruzi PLA(1) as a novel virulence factor implicated in parasite invasion. (c) 2012 Elsevier B.V. All rights reserved.