title: Heparan sulfate modulates kinin release by Trypanosoma cruzi through the activity of cruzipain.
abstract: Trypanosoma cruzi activates the kinin pathway through the activity of its major cysteine proteinase, cruzipain. Because kininogen molecules may be displayed on cell surfaces by binding to glycosaminoglycans, we examined whether the ability of cruzipain to release kinins from high molecular weight kininogen (HK) is modulated by heparan sulfate (HS). Kinetic assays show that HS reduces the cysteine proteinase inhibitory activity (K(i app)) of HK about 10-fold. Conversely, the catalytic efficiency of cruzipain on kinin-related synthetic fluorogenic substrates is enhanced up to 6-fold in the presence of HS. Analysis of the HK breakdown products generated by cruzipain indicated that HS changes the pattern of HK cleavage products. Direct measurements of bradykinin demonstrated an up to 35-fold increase in cruzipain-mediated kinin liberation in the presence of HS. Similarly, kinin release by living trypomastigotes increased up to 10-fold in the presence of HS. These studies suggest that the efficiency of T. cruzi to initiate kinin release is potently enhanced by the mutual interactions between cruzipain, HK, and heparan sulfate proteoglycans.
authors.affiliation: Instituto de Biofisica Carlos Chagas Filho, Universidade do Brasil, CCS, Bloco G, Cidade Universitária, CEP 21944-900, Rio de Janeiro, Brazil.
authors.forename: Ana Paula C A
authors.initials: AP
authors.lastname: Lima
authors.forename: Paulo C
authors.initials: PC
authors.lastname: Almeida
authors.forename: Ivarne L S
authors.initials: IL
authors.lastname: Tersariol
authors.forename: Veronica
authors.initials: V
authors.lastname: Schmitz
authors.forename: Alvin H
authors.initials: AH
authors.lastname: Schmaier
authors.forename: Luiz
authors.initials: L
authors.lastname: Juliano
authors.forename: Isaura Y
authors.initials: IY
authors.lastname: Hirata
authors.forename: Werner
authors.initials: W
authors.lastname: Müller-Esterl
authors.forename: Jair R
authors.initials: JR
authors.lastname: Chagas
authors.forename: Julio
authors.initials: J
authors.lastname: Scharfstein
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006497:Heparan Sulfate / Q000494:pharmacology*; D007700:Kinetics; D007704:Kininogens / Q000378:metabolism; D007705:Kinins / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D015800:Protozoan Proteins; D013379:Substrate Specificity; D014349:Trypanosoma cruzi / Q000187:drug effects / Q000201:enzymology*
chemical_list: D003546:Cysteine Endopeptidases; D006497:Heparan Sulfate; D007704:Kininogens; D007705:Kinins; D010446:Peptide Fragments; D015800:Protozoan Proteins; C063214:cruzipain