Trypanosoma cruzi trypomastigotes adhere to extracellular matrix (ECM) to invade mammalian host c... more Trypanosoma cruzi trypomastigotes adhere to extracellular matrix (ECM) to invade mammalian host cells regulating intracellular signaling pathways. Herein, resin-assisted enrichment of thiols combined with mass spectrometry were employed to map site-specific S-nitrosylated (SNO) proteins from T. cruzi trypomastigotes incubated (MTy) or not (Ty) with ECM. We confirmed the reduction of S-nitrosylation upon incubation with ECM, associated with a rewiring of the subcellular distribution and intracellular signaling pathways. Forty, 248 and 85 SNO-peptides were identified only in MTy, Ty or in both conditions, respectively. SNO proteins were enriched in ribosome, transport, carbohydrate and lipid metabolisms. Nitrosylation of histones H2B and H3 on Cys64 and Cys126, respectively, is described. Protein-protein interaction networks revealed ribosomal proteins, proteins involved in carbon and fatty acid metabolism to be among the enriched protein complexes. Kinases, phosphatases and enzymes involved in the metabolism of carbohydrates, lipids and amino acids were identified as nitrosylated and phosphorylated, suggesting a post-translational modifications crosstalk. In silico mapping of nitric oxide synthase (NOS) genes, previously uncharacterized, matched to four putative T. cruzi proteins expressing C-terminal NOS domain. Our results provide the first site-specific characterization of S-nitrosylated proteins in T. cruzi and their modulation upon ECM incubation before infection of the mammalian hosts. SIGNIFICANCE: Protein S-nitrosylation represents a major molecular mechanism for signal transduction by nitric oxide. We present for the first time a proteomic profile of S-nitrosylated proteins from infective forms of T. cruzi, showing a decrease in SNO proteins after incubation of the parasite with the extracellular matrix, a necessary step for the parasite invasion of the host mammalian cells. We also show for the first time nitrosylation of H2B (Cys64) and H3 (Cys126) histones, sites not conserved in higher eukaryotic cells, and suggest that some specific histone isoforms are sensitive to NO signaling. S-nitrosylation in H2B and H3 histones are more abundant in MTy. Moreover, proteins involved in translation, glycolytic pathway and fatty acid metabolism are enriched in the present dataset. Comparison of the SNO proteome and the phosphoproteome, obtained previously under the same experimental conditions, show that most of the proteins sharing both modifications are involved in metabolic pathways, transport and ribosome function. The data suggest that both PTMs are involved in reprogramming the metabolism of T. cruzi in response to environmental changes. Although NO synthesis was detected in T. cruzi, the identification of NOS remains elusive. Analysis in silico showed two genes similar in domains to NADPH-dependent cytochrome-P450 reductase and two putative oxidoreductases, but no oxygenase domain of NOS was mapped in the T. cruzi genome. It is tempting to speculate that NO synthase-like from T. cruzi and its early NO-mediated pathways triggered in response to host interaction constitute potential diagnostic and therapeutic targets.
The binding of 125I-laminin to trypomastigotes is specific and 2-5 x 10(3) laminin-binding sites ... more The binding of 125I-laminin to trypomastigotes is specific and 2-5 x 10(3) laminin-binding sites were calculated to be present on the surface of a live trypomastigote. Anti-laminin antibodies were able to inhibit the invasion of cultured cells by trypomastigotes (62-75%), suggesting that laminin may be involved in the adhesion of the parasite to host cells. By affinity chromatography, an 85-kDa glycoprotein was isolated (laminin-binding glycoprotein, LBG) from trypomastigote lysates, but not from epimastigote lysates. It is suggested that at least fragment E8 (but not E1') from laminin could be involved in the reaction which is independent of the carbohydrate moieties from both ligand and receptor. It is also shown that LBG is a member of the Tc-85 family, previously shown to be related to the invasion process of the parasite.
Tc-85 is an 85-kDa surface glycoprotein specific for the trypomastigote stage of Trypanosoma cruz... more Tc-85 is an 85-kDa surface glycoprotein specific for the trypomastigote stage of Trypanosoma cruzi which has been implicated in the invasion of host cells by the parasite. Tc-85 has a half-life of 3.5-4 h and is synthesized as a 95-kDa precursor. Processing of the 95-kDa precursor is inhibited by N-p-tosyl-L-lysine chloromethyl ketone, p-chloromercuriphenylsulfonic acid, iodoacetamide or N-ethylmaleimide, but not by aprotinin, antipain or phenylmethylsulfonil fluoride. Tc-85, but not the precursor, is rapidly shed into the medium, allowing a correlation between the decrease of Tc-85 in trypomastigotes and its increase in the culture medium. The shedding of Tc-85 was inhibited 50% by 1 microM tunicamycin, but not by 10 microM swainsonine or 10 microM 1-deoxynojirimycin under the experimental conditions employed. This suggests that N-linked oligosaccharides are important for the shedding phenomenon, although it appears that they do not have to be fully processed for shedding to occur.
Summary This protocol describes the genomic phage (gPhage) display platform, a large-scale antige... more Summary This protocol describes the genomic phage (gPhage) display platform, a large-scale antigen and epitope mapping technique. We constructed a gPhage display peptide library of a eukaryotic organism, Trypanosoma cruzi (causative agent of Chagas disease), to map the antibody response landscape against the parasite. Here, we used an organism with a relatively large but intronless genome, although future applications could include other prevalent or (re)emerging infectious organisms carrying genomes with a limited number of introns. For complete details on the use and execution of this protocol, please refer to Teixeira et al. (2021).
Summary Large-scale mapping of antigens and epitopes is pivotal for developing immunotherapies bu... more Summary Large-scale mapping of antigens and epitopes is pivotal for developing immunotherapies but challenging, especially for eukaryotic pathogens, owing to their large genomes. Here, we developed an integrated platform for genome phage display (gPhage) to show that unbiased libraries of the eukaryotic parasite Trypanosoma cruzi enable the identification of thousands of antigens recognized by serum samples from patients with Chagas disease. Because most of these antigens are hypothetical proteins, gPhage provides evidence of their expression during infection. We built and validated a comprehensive map of Chagas disease antibody response to show how linear and putative conformation epitopes, many rich in repetitive elements, allow the parasite to evade a buildup of neutralizing antibodies directed against protein domains that mediate infection pathogenesis. Thus, the gPhage platform is a reproducible and effective tool for rapid simultaneous identification of epitopes and antigens, not only in Chagas disease but perhaps also in globally emerging/reemerging acute pathogens.
Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas / Sociedade Brasileira de Biofísica ... [et al.], 1994
A hydrophobic fraction isolated from trypomastigotes of Trypanosoma cruzi is being characterized ... more A hydrophobic fraction isolated from trypomastigotes of Trypanosoma cruzi is being characterized using immunological and chemical techniques. The lipopeptidophosphoglycan (LPPG) was identified in this fraction since it gave a positive reaction with anti-LPPG rabbit serum and had similar structural features such as the presence of ceramide as the lipid moiety, furanoic galactose, and a glycan moiety consistent with that obtained from an authentic sample of epimastigote LPPG, as judged by thin-layer chromatography. Furthermore, the hydrophobic fraction contained other glycolipids with different structural features. The lipid moiety of these compounds is alkylglycerol rather than a ceramide, the carbohydrate chain appears to be less complex than that in LPPG and no reactivity was observed towards an anti-LPPG serum.
Trypanosoma cruzi trypomastigotes adhere to extracellular matrix (ECM) to invade mammalian host c... more Trypanosoma cruzi trypomastigotes adhere to extracellular matrix (ECM) to invade mammalian host cells regulating intracellular signaling pathways. Herein, resin-assisted enrichment of thiols combined with mass spectrometry were employed to map site-specific S-nitrosylated (SNO) proteins from T. cruzi trypomastigotes incubated (MTy) or not (Ty) with ECM. We confirmed the reduction of S-nitrosylation upon incubation with ECM, associated with a rewiring of the subcellular distribution and intracellular signaling pathways. Forty, 248 and 85 SNO-peptides were identified only in MTy, Ty or in both conditions, respectively. SNO proteins were enriched in ribosome, transport, carbohydrate and lipid metabolisms. Nitrosylation of histones H2B and H3 on Cys64 and Cys126, respectively, is described. Protein-protein interaction networks revealed ribosomal proteins, proteins involved in carbon and fatty acid metabolism to be among the enriched protein complexes. Kinases, phosphatases and enzymes involved in the metabolism of carbohydrates, lipids and amino acids were identified as nitrosylated and phosphorylated, suggesting a post-translational modifications crosstalk. In silico mapping of nitric oxide synthase (NOS) genes, previously uncharacterized, matched to four putative T. cruzi proteins expressing C-terminal NOS domain. Our results provide the first site-specific characterization of S-nitrosylated proteins in T. cruzi and their modulation upon ECM incubation before infection of the mammalian hosts. SIGNIFICANCE: Protein S-nitrosylation represents a major molecular mechanism for signal transduction by nitric oxide. We present for the first time a proteomic profile of S-nitrosylated proteins from infective forms of T. cruzi, showing a decrease in SNO proteins after incubation of the parasite with the extracellular matrix, a necessary step for the parasite invasion of the host mammalian cells. We also show for the first time nitrosylation of H2B (Cys64) and H3 (Cys126) histones, sites not conserved in higher eukaryotic cells, and suggest that some specific histone isoforms are sensitive to NO signaling. S-nitrosylation in H2B and H3 histones are more abundant in MTy. Moreover, proteins involved in translation, glycolytic pathway and fatty acid metabolism are enriched in the present dataset. Comparison of the SNO proteome and the phosphoproteome, obtained previously under the same experimental conditions, show that most of the proteins sharing both modifications are involved in metabolic pathways, transport and ribosome function. The data suggest that both PTMs are involved in reprogramming the metabolism of T. cruzi in response to environmental changes. Although NO synthesis was detected in T. cruzi, the identification of NOS remains elusive. Analysis in silico showed two genes similar in domains to NADPH-dependent cytochrome-P450 reductase and two putative oxidoreductases, but no oxygenase domain of NOS was mapped in the T. cruzi genome. It is tempting to speculate that NO synthase-like from T. cruzi and its early NO-mediated pathways triggered in response to host interaction constitute potential diagnostic and therapeutic targets.
The binding of 125I-laminin to trypomastigotes is specific and 2-5 x 10(3) laminin-binding sites ... more The binding of 125I-laminin to trypomastigotes is specific and 2-5 x 10(3) laminin-binding sites were calculated to be present on the surface of a live trypomastigote. Anti-laminin antibodies were able to inhibit the invasion of cultured cells by trypomastigotes (62-75%), suggesting that laminin may be involved in the adhesion of the parasite to host cells. By affinity chromatography, an 85-kDa glycoprotein was isolated (laminin-binding glycoprotein, LBG) from trypomastigote lysates, but not from epimastigote lysates. It is suggested that at least fragment E8 (but not E1') from laminin could be involved in the reaction which is independent of the carbohydrate moieties from both ligand and receptor. It is also shown that LBG is a member of the Tc-85 family, previously shown to be related to the invasion process of the parasite.
Tc-85 is an 85-kDa surface glycoprotein specific for the trypomastigote stage of Trypanosoma cruz... more Tc-85 is an 85-kDa surface glycoprotein specific for the trypomastigote stage of Trypanosoma cruzi which has been implicated in the invasion of host cells by the parasite. Tc-85 has a half-life of 3.5-4 h and is synthesized as a 95-kDa precursor. Processing of the 95-kDa precursor is inhibited by N-p-tosyl-L-lysine chloromethyl ketone, p-chloromercuriphenylsulfonic acid, iodoacetamide or N-ethylmaleimide, but not by aprotinin, antipain or phenylmethylsulfonil fluoride. Tc-85, but not the precursor, is rapidly shed into the medium, allowing a correlation between the decrease of Tc-85 in trypomastigotes and its increase in the culture medium. The shedding of Tc-85 was inhibited 50% by 1 microM tunicamycin, but not by 10 microM swainsonine or 10 microM 1-deoxynojirimycin under the experimental conditions employed. This suggests that N-linked oligosaccharides are important for the shedding phenomenon, although it appears that they do not have to be fully processed for shedding to occur.
Summary This protocol describes the genomic phage (gPhage) display platform, a large-scale antige... more Summary This protocol describes the genomic phage (gPhage) display platform, a large-scale antigen and epitope mapping technique. We constructed a gPhage display peptide library of a eukaryotic organism, Trypanosoma cruzi (causative agent of Chagas disease), to map the antibody response landscape against the parasite. Here, we used an organism with a relatively large but intronless genome, although future applications could include other prevalent or (re)emerging infectious organisms carrying genomes with a limited number of introns. For complete details on the use and execution of this protocol, please refer to Teixeira et al. (2021).
Summary Large-scale mapping of antigens and epitopes is pivotal for developing immunotherapies bu... more Summary Large-scale mapping of antigens and epitopes is pivotal for developing immunotherapies but challenging, especially for eukaryotic pathogens, owing to their large genomes. Here, we developed an integrated platform for genome phage display (gPhage) to show that unbiased libraries of the eukaryotic parasite Trypanosoma cruzi enable the identification of thousands of antigens recognized by serum samples from patients with Chagas disease. Because most of these antigens are hypothetical proteins, gPhage provides evidence of their expression during infection. We built and validated a comprehensive map of Chagas disease antibody response to show how linear and putative conformation epitopes, many rich in repetitive elements, allow the parasite to evade a buildup of neutralizing antibodies directed against protein domains that mediate infection pathogenesis. Thus, the gPhage platform is a reproducible and effective tool for rapid simultaneous identification of epitopes and antigens, not only in Chagas disease but perhaps also in globally emerging/reemerging acute pathogens.
Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas / Sociedade Brasileira de Biofísica ... [et al.], 1994
A hydrophobic fraction isolated from trypomastigotes of Trypanosoma cruzi is being characterized ... more A hydrophobic fraction isolated from trypomastigotes of Trypanosoma cruzi is being characterized using immunological and chemical techniques. The lipopeptidophosphoglycan (LPPG) was identified in this fraction since it gave a positive reaction with anti-LPPG rabbit serum and had similar structural features such as the presence of ceramide as the lipid moiety, furanoic galactose, and a glycan moiety consistent with that obtained from an authentic sample of epimastigote LPPG, as judged by thin-layer chromatography. Furthermore, the hydrophobic fraction contained other glycolipids with different structural features. The lipid moiety of these compounds is alkylglycerol rather than a ceramide, the carbohydrate chain appears to be less complex than that in LPPG and no reactivity was observed towards an anti-LPPG serum.
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Papers by Walter Colli