Phosphatidylinositol-specific phospholipase C (PI-PLC) cleavage of GPI-anchored surface molecules of Trypanosoma cruzi triggers in vitro morphological reorganization of trypomastigotes.
Trypanosoma cruzi trypomastigotes treated with phosphatidylinositol-specific phospholipase C (PI-PLC) in vitro are rapidly induced to differentiate into round forms. Using confocal microscopy, we were able to show that trypomastigotes treated with PI-PLC initiate the process of flagellum remodeling by 30 sec after contact with the enzyme and amastigote-like forms are detected as early as 10 min after PI-PLC treatment. Scanning and transmission electron microscopy indicate that trypomastigotes undergo a previously undescribed process of flagellum circularization and internalization. Analysis of the flagellar complex with monoclonal antibody 4D9 shows heterogeneous labeling among the parasites, suggesting a remodeling of these molecules. After PI-PLC treatment, parasites rapidly lose the surface marker Ssp-3 and 24 h post-treatment they begin to exhibit a circular nucleus and a rod-shaped kinetoplast. By flow cytometry analysis and confocal microscopy, the Ssp-4 amastigote-specific epitope can be detected on the parasite surface. This indicates that the release of trypomastigote GPI-anchored molecules by exogenous PI-PLC in vitro can trigger morphological changes.
Mortara
R A
RA
Departamento de Microbiologia, Imunologia e Parasitologia and Centro de Microscopia Eletr nica, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brasil. renato@ecb.epm.br
Minelli
L M
LM
Vandekerckhove
F
F
Nussenzweig
V
V
Ramalho-Pinto
F J
FJ
D000818:Animals; D003599:Cytoskeleton / Q000648:ultrastructure; D005407:Flagella / Q000502:physiology; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D014349:Trypanosoma cruzi / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism*
D017261:Glycosylphosphatidylinositols; D010738:Type C Phospholipases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase