Formation and remodeling of inositolphosphoceramide during differentiation of Trypanosoma cruzi from trypomastigote to amastigote.
Differentiation of Trypanosoma cruzi trypomastigotes to amastigotes inside myoblasts or in vitro, at low extracellular pH, in the presence of [(3)H]palmitic acid or [(3)H]inositol revealed differential labeling of inositolphosphoceramide and phosphatidylinositol, suggesting that a remodeling process takes place in both lipids. Using (3)H-labeled inositolphosphoceramide and phosphatidylinositol as substrates, we demonstrated the association of at least five enzymatic activities with the membranes of amastigotes and trypomastigotes. These included phospholipase A(1), phospholipase A(2), inositolphosphoceramide-fatty acid hydrolase, acyltransferase, and a phospholipase C releasing either ceramide or a glycerolipid from the inositolphospholipids. These enzymes may be acting in remodeling reactions leading to the anchor of mature glycoproteins or glycoinositolphospholipids and helping in the transformation of the plasma membrane, a necessary step in the differentiation of slender trypomastigotes to round amastigotes. Synthesis of inositolphosphoceramide and particularly of glycoinositolphospholipids was inhibited by aureobasidin A, a known inhibitor of fungal inositolphosphoceramide synthases. The antibiotic impaired the differentiation of trypomastigotes at acidic pH, as indicated by an increased appearance of intermediate forms and a decreased expression of the Ssp4 glycoprotein, a characteristic marker of amastigote forms. Aureobasidin A was also toxic to differentiating trypomastigotes at acidic pH but not to trypomastigotes maintained at neutral pH. Our data suggest that inositolphosphoceramide is implicated in T. cruzi differentiation and that its metabolism could provide important targets for the development of antiparasitic therapies.
Salto
Maria Laura
ML
Laboratory of Molecular Parasitology, Department of Pathobiology and Center for Zoonoses Research, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, 61802, USA.
Bertello
Laura E
LE
Vieira
Mauricio
M
Docampo
Roberto
R
Moreno
Silvia N J
SN
de Lederkremer
Rosa M
RM
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D014355:Chagas Disease / Q000469:parasitology*; D047630:Depsipeptides; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006028:Glycosphingolipids / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008562:Membrane Glycoproteins / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism; D008854:Microscopy, Electron; D010456:Peptides, Cyclic / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000378:metabolism; D014349:Trypanosoma cruzi / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure
D047630:Depsipeptides; D004791:Enzyme Inhibitors; D006028:Glycosphingolipids; D008562:Membrane Glycoproteins; D008563:Membrane Lipids; D010456:Peptides, Cyclic; D010716:Phosphatidylinositols; C025524:inositolphosphoceramides; C071398:aureobasidin A