title: A role for protease activity and host-cell permeability during the process of Trypanosoma cruzi egress from infected cells.
abstract: The mechanism by which Trypanosoma cruzi egresses from infected cells at the end of the intracellular replication cycle is not understood. This study explored the role of T. cruzi-derived proteases and host-cell membrane permeability during the parasite's egress process. Treatment with a fluoromethyl ketone, known to inhibit the parasite's major protease, significantly reduced parasite egress. In addition, in the late stages of intracellular infection, cells infected with T. cruzi showed increased permeability as evidenced by dye exclusion tests. Furthermore, parasites could be antibody stained inside host cells without chemical permeabilization of the plasma membrane. These results suggest that in advanced stages of the intracellular cycle of T. cruzi, the host cells lose membrane integrity. Previous studies in our laboratory have found that antibodies present in sera of mice chronically infected with T. cruzi (antiegressin) bind the surface of infected cells and reduce parasite egress. In agreement with these reports, western blot analysis showed that several proteins in infected cell membrane extracts reacted with antibodies from infected mouse serum. The findings reported herein might have implications in the process of T. cruzi egress, as well as in the mechanism of action of antiegressin.
authors.affiliation: Molecular and Cellular Biology Program, Tropical Disease Institute, Ohio University College of Osteopathic Medicine, Athens, Ohio 45701, USA. jc207393@ohio.edu
authors.forename: Jaime
authors.initials: J
authors.lastname: Costales
authors.forename: Edwin C
authors.initials: EC
authors.lastname: Rowland
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000502:physiology*; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000469:parasitology; D019084:Fluorescent Antibody Technique, Indirect; D007106:Immune Sera / Q000276:immunology; D047468:Immunoprecipitation; D051379:Mice; D008807:Mice, Inbred BALB C; D009439:Neuraminidase / Q000737:chemistry; D010447:Peptide Hydrolases / Q000378:metabolism*; D015800:Protozoan Proteins; D014343:Trypan Blue / Q000378:metabolism; D014349:Trypanosoma cruzi / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D000515:alpha 1-Antitrypsin / Q000032:analysis
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D004396:Coloring Agents; D015853:Cysteine Proteinase Inhibitors; D007106:Immune Sera; D015800:Protozoan Proteins; D000515:alpha 1-Antitrypsin; C080435:phenylalanylarginine fluoromethyl ketone; D009439:Neuraminidase; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases; C063214:cruzipain; D014343:Trypan Blue