title: Plasmodium falciparum proteases hydrolyze plasminogen, generating angiostatin-like fragments.
abstract: Malaria is a disease caused by Plasmodium parasites and remains one of the most prevalent and persistent maladies, affecting hundreds of millions of people. In the present work, we evaluated the capability of Plasmodium falciparum proteases to hydrolyze the multifunctional protein plasminogen, which is implicated in angiogenesis and coagulation processes by the generation of angiostatin and plasmin, respectively. Using fluorescence microscopy, we visualized the internalization of FITC-labeled plasminogen in erythrocytes infected by P. falciparum and showed that the parasites are able to hydrolyze the protein. The cleavage of plasminogen by the P. falciparum proteases was also observed by SDS-PAGE, followed by immunoblotting with anti-angiostatin antibody. N-terminal sequencing of the main generated fragments indicated that they are comprised in the five plasminogen kringle domains, suggesting as being angiostatin-like peptides. This assumption was reinforced by the demonstration that the products of plasminogen processing mimic angiostatin functions, including the capability to inhibit angiogenesis and to stimulate calcium response in endothelial cells in vitro. However, no plasmin activity was detected after plasminogen hydrolysis by P. falciparum. Nonetheless, exogenous tissue plasminogen activator (tPA) activated plasmin in infected erythrocytes, suggesting that the uptake of plasminogen by P. falciparum may be modulated by the vertebrate host. Taken together, the data presented here provide evidence for the processing of host plasminogen by malaria parasites to generate active fragments that may modulate host physiology events during malaria infection.
authors: Departamento de Biofísica, Universidade Federal de São Paulo, Rua Pedro de Toledo, 699, 7° andar, 04039-032 São Paulo, Brazil.
authors: Pollyana M S
authors: PM
authors: Melo
authors: Departamento de Biofísica, Universidade Federal de São Paulo, Rua Pedro de Toledo, 699, 7° andar, 04039-032 São Paulo, Brazil.
authors: Piero
authors: P
authors: Bagnaresi
authors: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Rua Botucatu, 862, 8° andar, 04023-062 São Paulo, SP, Brazil.
authors: Thaysa
authors: T
authors: Paschoalin
authors: Departamento de Biofísica, Universidade Federal de São Paulo, Rua Pedro de Toledo, 699, 7° andar, 04039-032 São Paulo, Brazil.
authors: Izaura Y
authors: IY
authors: Hirata
authors: Departamento de Biociências, Universidade Federal de São Paulo, Avenida Ana Costa, 95, 11060-001 Santos, SP, Brazil.
authors: Marcos L
authors: ML
authors: Gazarini
authors: Departamento de Biofísica, Universidade Federal de São Paulo, Rua Pedro de Toledo, 699, 7° andar, 04039-032 São Paulo, Brazil. Electronic address: ak.carmona@unifesp.br.
authors: Adriana K
authors: AK
authors: Carmona
mesh_terms: D043168:Angiostatins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000378:metabolism / Q000469:parasitology; D005341:Fibrinolysin / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D054884:Host-Pathogen Interactions; D006801:Humans; D006868:Hydrolysis; D015151:Immunoblotting; D010447:Peptide Hydrolases / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000201:enzymology*; D013194:Staining and Labeling
chemical_list: D005456:Fluorescent Dyes; D043168:Angiostatins; D010958:Plasminogen; D010447:Peptide Hydrolases; D005341:Fibrinolysin; D016650:Fluorescein-5-isothiocyanate
keywords: Angiostatin; Malaria; Plasmin; Plasminogen; Plasmodium