INHIBITORS of the MAJOR CYSTEINYL PROTEINASE (GP57/51) IMPAIR HOST-CELL INVASION and ARREST the INTRACELLULAR DEVELOPMENT of TRYPANOSOMA-CRUZI INVITRO

INHIBITORS of the MAJOR CYSTEINYL PROTEINASE (GP57/51) IMPAIR HOST-CELL INVASION and ARREST the INTRACELLULAR DEVELOPMENT of TRYPANOSOMA-CRUZI INVITRO

Autor Meirelles, MNL Google Scholar
Juliano, L. Google Scholar
Carmona, E. Google Scholar
Silva, S. G. Google Scholar
Costa, E. M. Google Scholar
Murta, ACM Google Scholar
Scharfstein, J. Google Scholar
Instituição Universidade Federal do Rio de Janeiro (UFRJ)
INST OSWALDO CRUZ
INST BUTANTAN
Universidade Federal de São Paulo (UNIFESP)
Resumo Peptidyl diazomethane (PDAM) derivatives, a class of irreversible inhibitors for cysteine proteinase, were screened for the ability to impair Trypanosoma cruzi invasion and intracellular development in primary cultures of heart muscle cells (HMC). T. cruzi GP57/51, a purified cysteinyl proteinase, and the substrate Z-Phe-Arg-NHMec were used to determine inhibition rate constants (k'+2) by continuous kinetic assays. the k'+2 values ranged from 25 400 to 2 800. the best inhibitors of GP57/51 had bulky hydrophobic residues in the P1 position (in addition to P2), the S1 sub-site specificity of the enzyme being thus similar to mammalian cathepsin L. the effects of these PDAM on parasite infectivity were then investigated. the ability to invade HMC was markedly impaired when trypomastigotes were briefly exposed to 10-mu-M of Z-(S-Bzl)Cys-Phe-CHN2. Striking effects were observed when PDAM were added to HMC cultures that had been previously infected with trypomastigotes: Z-(S-Bzl)Cys-Phe-CHN, with an IC50 of 0.4-mu-M, and less markedly Z-Phe-Phe-CHN, and Z-Tyr-Phe-CHN2 (or Z-Phe-Tyr-CHN2) blocked amastigote replication as well as their transformation into trypomastigotes, thereby arresting intracellular development. Bz-Phe-Gly-CHN2, in contrast, failed to display antiparasite activity. Direct characterization of the target cysteinyl proteinase was sought, by incubating viable amastigotes or infected HMC with Z-[I-125]Tyr-Phe-CHN2. Affinity labeling implicated GP57/51 as the major cysteinyl proteinase target for this probe. We propose that T. cruzi intracellular development is critically dependent on GP57/51 (cruzipain). Selective inhibitors for this cysteinyl proteinase may have therapeutic potential.
Palavra-chave TRYPANOSOMA-CRUZI
PROTOZOA
CYSTEINE PROTEINASE
PROTEASE INHIBITOR
Idioma Inglês
Data de publicação 1992-06-01
Publicado em Molecular and Biochemical Parasitology. Amsterdam: Elsevier B.V., v. 52, n. 2, p. 175-184, 1992.
ISSN 0166-6851 (Sherpa/Romeo, fator de impacto)
Publicador Elsevier B.V.
Extensão 175-184
Fonte http://dx.doi.org/10.1016/0166-6851(92)90050-T
Direito de acesso Acesso restrito
Tipo Artigo
Web of Science WOS:A1992HX35800004
Endereço permanente http://repositorio.unifesp.br/handle/11600/25253

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