Bowman-Birk inhibitors (BBIs) are protein molecules containing two inhibitory domains for enzymes similar to trypsin and chymotrypsin. Interest in these inhibitors arose from their properties against the cancer chemically induced by 1,2-dimethylhydrazine (DMH). In this study the effect of two BBI preparations (from Glycine max and Macrotyloma axillare) were evaluated for the prevention of colorectal neoplasia induced by intraperitoneal injections of DMH, given at a dose of 30 mg/kg, during 12 weeks. Mice treated with DMH presented histopathological alterations consistent with tumor development, augmented CD44 expression and increased proteasome peptidase activities. Lysosomal fractions, obtained from the intestines, were chromatographed in a Sepharose-BBI column and increased activity for trypsin and chymotrypsin-like proteases recovered from DMH-treated animals. In parallel, mice treated for eight weeks with BBIs showed a decrease in the chymotrypsin and trypsin-like proteasome activities compared to animals fed on normal diet. For the groups receiving simultaneous treatment with DMH and BBIs, dysplasic lesions were not observed and proteasome peptidase activities were similar to the control group after the 24th week. These results suggest that the mechanism by which BBIs could prevent the appearance of pre neoplastic lesions is associated with inhibition of both the lysosomal and proteasome-dependent proteolytic pathways.

Recebido em 5/10/06; aceito em 18/12/06; publicado na web em 17/7/07 SYNTHESIS OF AMIDES AND SULFONAMIDES OF β-D-GALACTOPYRANOSYLAMINE AND β-LACTOSYLAMINE AND EVALUATION OF THEIR INTERACTIONS WITH THE LECTINS FROM Erythrina cristagalli AND Ricinus communis.We report herein the synthesis of some β-D-galactopyranosylamine and β-lactosylamine amides and sulfonamides. The interactions of these compounds with lectins from the seeds of Erythrina cristagalli (LEC) and Ricinus communis (RCA120) were evaluated in a hemagglutination inhibitory activity assay. D-Galactose and lactose were used as reference compounds. The β-lactosylamine amides and sulfonamides were nearly as active as lactose in inhibiting LEC mediated hemagglutination and were less active against RCA120 agglutinin. The β-D-galactopyranosylamine amides and sulfonamides were, with one exception, considerably less active than Dgalactose in the assay with both lectins.Keywords: carbohydrates; plant lectins; amides. INTRODUÇÃOLectinas são proteínas desprovidas de atividade enzimática que se ligam de maneira reversível e específica a carboidratos. Distinguem-se das imunoglobulinas, que reconhecem especificamente antígenos, eventualmente sacarídicos, seja estruturalmente, seja porque estas últimas dependem de estímulo antigênico para serem sintetizadas. Essa classe de proteínas estruturalmente diversificada é amplamente distribuída na natureza e, em geral, está relacionada a processos de reconhecimento celular mediados por suas interações com carboidratos [1][2][3][4] . É reconhecida a participação destas interações em processos fisiológicos e patológicos importantes, tais como no controle do tráfego intracelular de glicoproteínas, na adesão de agentes infecciosos à célula hospedeira, nas interações do sistema imune e na metástase de tumores 5 . A seletividade das interações entre lectinas e carboidratos teve notável importância histórica pela contribuição na descoberta dos grupos sangüíneos humanos 6 . Em vista do exposto, as lectinas têm sido consideradas potenciais alvos moleculares de substâncias com atividades antitumoral e antiparasitária 7,8 . Denota-se a seletividade pela distinção, por parte da lectina, entre ligantes monossacarídeos, sendo comum a classificação das lectinas de acordo com o monossacarídeo pelo qual exibe maior afinidade, normalmente aqueles presentes em células eucarióticas: D-manose, D-galactose/N-acetil-D-galactosamina, Nacetil-D-glicosamina, L-fucose e ácido N-acetil-D-neuramínico 5 . O ensaio de hemaglutinação apresenta-se como uma das técni-cas mais simples de avaliação das interações entre carboidratos e lectinas. Seu vasto emprego deve-se à facilidade de obtenção dos eritrócitos do tecido sangüíneo e à riqueza qualitativa dos resíduos sacarídicos que são expressos em suas superfícies. Existem diversos estudos em que a propriedade aglutinante das lectinas é utilizada para a obtenção de dados da composição sacarídica da superfí-cie de outros tipos celulares, como por ex., de células tumorais 1,9,10 . A aglutinação celular promovida...

BackgroundTrypanosoma cruzi, a hemoflagellate protozoan parasite and the etiological agent of Chagas disease (CD), exhibits great genetic and biological diversity. Infected individuals may present clinical manifestations with different levels of severity. Several hypotheses have been proposed to attempt to correlate the diversity of clinical signs and symptoms to the genetic variability of T. cruzi. This work aimed to investigate the differential expression of proteins from two distinct genetic groups of T. cruzi (discrete typing units TcI and TcII), isolated from chronically infected individuals displaying the cardiac form of CD. For this purpose, epimastigote forms of the two isolates were cultured in vitro and the cells recovered for protein extraction. Comparative two-dimensional (2D) gel electrophoreses were performed and differentially expressed spots selected for identification by mass spectrometry, followed by database searching and protein categorization.ResultsThe 2D electrophoretic profiles revealed the complex composition of the T. cruzi extracted proteome. Protein spots were distributed along the entire pH and molecular mass ranges attesting for the integrity of the protein preparations. In total, 46 differentially expressed proteins were identified present in 40 distinct spots found in the comparative gel analyses. Of these, 16 displayed upregulation in the gel from TcI-typed parasites and 24 appeared overexpressed in the gel from TcII-typed parasites. Functional characterization of differentially expressed proteins revealed major alterations associated with stress response, lipid and amino acid metabolism in parasites of the TcII isolate, whilst those proteins upregulated in the TcI sample were primarily linked to central metabolic pathways.ConclusionsThe comparative 2D-gel electrophoresis allowed detection of major differences in protein expression between two T. cruzi isolates, belonging to the TcI and TcII genotypes. Our findings suggest that patients displaying the cardiac form of the disease harbor parasites capable of exhibiting distinct proteomic profiles. This should be of relevance to disease prognosis and treatment.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3181-1) contains supplementary material, which is available to authorized users.

The PR-11 peptide corresponds to the N-terminal and active region of the endogenously synthesized PR-39 molecule, of porcine origin. It is known to possess various biological effects including antimicrobial properties, angiogenic and anti-inflammatory activities. Apart from its reported activity as a proteasome inhibitor, a more comprehensive understanding of its function, at the molecular level, is still lacking. In this study, we used a label-free shotgun strategy to evaluate the proteomic alterations caused by exposure of cultured fibroblasts to the peptide PR-11. This approach revealed that more than half of the identified molecules were related to signalling, transcription and translation. Proteins directly associated to regulation of angiogenesis and interaction with the hypoxia-inducible factor 1-α (HIF-1α) were significantly altered. In addition, at least three differentially expressed molecules of the NF-κB pathway were detected, suggesting an anti-inflammatory property of PR-11. At last, we demonstrated novel potential ligands of PR-11, through its immobilization for affinity chromatography. Among the eluted molecules, gC1qR, a known complement receptor, appeared markedly enriched. This provided preliminary evidence of a PR-11 ligand possibly involved in the internalization of this peptide. Altogether, our findings contributed to a better understanding of the cellular pathways affected by PR-39 derived molecules.