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Ann A, Truong S, Peters J, Mootoo DR. Synthesis of alpha-Gal C-disaccharides. Bioorg Med Chem 2024; 112:117903. [PMID: 39236466 DOI: 10.1016/j.bmc.2024.117903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 08/15/2024] [Accepted: 08/27/2024] [Indexed: 09/07/2024]
Abstract
The synthesis of C-disaccharides of α-d-galactopyranosyl-(1 → 3)-d-galactopyranose (α-Gal), potential tools for studying the biology of α-Gal glycans, is described. The synthetic strategy, centers on the reaction of two easily available precursors 1,2-O-isopropylidene-d-glyceraldehyde and an α-C-glactosyl-E-crotylboronate, which affords a mixture of two diastereomeric anti-crotylation products. The stereoselectivity of this reaction was controlled with (R)- and (S)-TRIP catalysts, and the appropriate diastereomer was transformed to C-linked disaccharides of α-Gal, in which the aglycone segment comprised O-, C- and S-glycoside entities that can enable glycoconjugate synthesis.
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Affiliation(s)
- Alex Ann
- Department of Chemistry, Hunter College and The Graduate Center of the City University of New York, New York, NY 10016, United States
| | - Steven Truong
- Department of Chemistry, Hunter College and The Graduate Center of the City University of New York, New York, NY 10016, United States
| | - Jiwani Peters
- Department of Chemistry, Hunter College and The Graduate Center of the City University of New York, New York, NY 10016, United States
| | - David R Mootoo
- Department of Chemistry, Hunter College and The Graduate Center of the City University of New York, New York, NY 10016, United States.
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Montoya AL, Gil ER, Vinales I, Estevao IL, Taboada P, Torrico MC, Torrico F, Marco JD, Almeida IC, Michael K. Big is not better: Comparing two alpha-Gal-bearing glycotopes in neoglycoproteins as biomarkers for Leishmania (Viannia) braziliensis infection. Carbohydr Res 2024; 536:109015. [PMID: 38198982 PMCID: PMC11366264 DOI: 10.1016/j.carres.2023.109015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/15/2023] [Accepted: 12/15/2023] [Indexed: 01/12/2024]
Abstract
The protozoan parasite Leishmania (Viannia) braziliensis is among Latin America's most widespread Leishmania species and is responsible for tegumentary leishmaniasis (TL). This disease has multiple clinical presentations, with cutaneous leishmaniasis (CL) being the most frequent. It manifests as one or a few localized skin ulcers, which can spread to other body areas. Hence, early diagnosis and treatment, typically with pentavalent antimonials, is critical. Traditional diagnostic methods, like parasite culture, microscopy, or the polymerase chain reaction (PCR) for detection of the parasite DNA, have limitations due to the uneven distribution of parasites in biopsy samples. Nonetheless, studies have revealed high levels of parasite-specific anti-α-Gal antibodies in L. (V.) braziliensis-infected patients. Previously, we demonstrated that the neoglycoprotein NGP28b, consisting of the L. (Leishmania) major type-2 glycoinositolphospholipid (GIPL)-3-derived trisaccharide Galpα1,6Galpα1,3Galfβ conjugated to bovine serum albumin (BSA) via a linker, acts as a reliable serological biomarker (BMK) for L. (V.) braziliensis infection in Brazil. This indicates the presence of GIPL-3 or a similar structure in this parasite, and its terminal trisaccharide either functions as or is part of an immunodominant glycotope. Here, we explored whether extending the trisaccharide with a mannose unit would enhance its efficacy as a biomarker for the serological detection of L. (V.) braziliensis. We synthesized the tetrasaccharide Galpα1,6Galpα1,3Galfβ1,3Manpα(CH2)3SH (G31SH) and conjugated it to maleimide-functionalized BSA to afford NGP31b. When we assessed the efficacy of NGP28b and NGP31b by chemiluminescent enzyme-linked immunosorbent assay on a cohort of CL patients with L. (V.) braziliensis infection from Bolivia and Argentina against a healthy control group, both NGPs exhibited similar or identical sensitivity, specificity, and accuracy. This finding implies that the mannose moiety at the reducing end is not part of the glycotope recognized by the parasite-specific anti-α-Gal antibodies in patients' sera, nor does it exert a relevant influence on the terminal trisaccharide's conformation. Moreover, the mannose does not seem to inhibit glycan-antibody interactions. Therefore, NGP31b is a viable and dependable BMK for the serodiagnosis of CL caused by L. (V.) braziliensis.
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Affiliation(s)
- Alba L Montoya
- Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Eileni R Gil
- Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Irodiel Vinales
- Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Igor L Estevao
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Paola Taboada
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA
| | - Mary Cruz Torrico
- Universidad Mayor de San Simón, Faculty of Medicine, and Fundación CEADES, Cochabamba, Bolivia
| | - Faustino Torrico
- Universidad Mayor de San Simón, Faculty of Medicine, and Fundación CEADES, Cochabamba, Bolivia
| | - Jorge Diego Marco
- Universidad Nacional de Salta (UNSa)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Patología Experimental, Facultad de Ciencias de la Salud, Universidad Nacional de Salta, Salta, Argentina
| | - Igor C Almeida
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA.
| | - Katja Michael
- Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79968, USA.
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Abal M, Balouz V, Lopez R, Giorgi ME, Marino C, Cruz CV, Altcheh J, Buscaglia CA. An α-Gal antigenic surrogate as a biomarker of treatment evaluation in Trypanosoma cruzi-infected children. A retrospective cohort study. PLoS Negl Trop Dis 2024; 18:e0011910. [PMID: 38236916 PMCID: PMC10826959 DOI: 10.1371/journal.pntd.0011910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/30/2024] [Accepted: 01/09/2024] [Indexed: 01/31/2024] Open
Abstract
BACKGROUND Proper evaluation of therapeutic responses in Chagas disease is hampered by the prolonged persistence of antibodies to Trypanosoma cruzi measured by conventional serological tests and by the lack of sensitivity of parasitological tests. Previous studies indicated that tGPI-mucins, an α-Gal (α-d-Galp(1→3)-β-d-Galp(1→4)-d-GlcNAc)-rich fraction obtained from T. cruzi trypomastigotes surface coat, elicit a strong and protective antibody response in infected individuals, which disappears soon after successful treatment. The cost and technical difficulties associated with tGPI-mucins preparation, however, preclude its routine implementation in clinical settings. METHODS/PRINCIPLE FINDINGS We herein developed a neoglycoprotein consisting of a BSA scaffold decorated with several units of a synthetic α-Gal antigenic surrogate (α-d-Galp(1→3)-β-d-Galp(1→4)-β-d-Glcp). Serological responses to this reagent, termed NGP-Tri, were monitored by means of an in-house enzyme-linked immunosorbent assay (α-Gal-ELISA) in a cohort of 82 T. cruzi-infected and Benznidazole- or Nifurtimox-treated children (3 days to 16 years-old). This cohort was split into 3 groups based on the age of patients at the time of treatment initiation: Group 1 comprised 24 babies (3 days to 5 months-old; median = 26 days-old), Group 2 comprised 31 children (7 months to 3 years-old; median = 1.0-year-old) and Group 3 comprised 26 patients (3 to 16 years-old; median = 8.4 years-old). A second, control cohort (Group 4) included 39 non-infected infants (3 days to 5 months-old; median = 31 days-old) born to T. cruzi-infected mothers. Despite its suboptimal seroprevalence (58.4%), α-Gal-ELISA yielded shorter median time values of negativization (23 months [IC 95% 7 to 36 months] vs 60 months [IC 95% 15 to 83 months]; p = 0.0016) and higher rate of patient negative seroconversion (89.2% vs 43.2%, p < 0.005) as compared to conventional serological methods. The same effect was verified for every Group, when analyzed separately. Most remarkably, 14 out of 24 (58.3%) patients from Group 3 achieved negative seroconversion for α-Gal-ELISA while none of them were able to negativize for conventional serology. Detailed analysis of patients showing unconventional serological responses suggested that, in addition to providing a novel tool to shorten follow-up periods after chemotherapy, the α-Gal-ELISA may assist in other diagnostic needs in pediatric Chagas disease. CONCLUSIONS/SIGNIFICANCE The tools evaluated here provide the cornerstone for the development of an efficacious, reliable, and straightforward post-therapeutic marker for pediatric Chagas disease.
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Affiliation(s)
- Manuel Abal
- Instituto de Investigaciones Biotecnológicas (IIBio), Universidad Nacional de San Martín (UNSAM), and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Escuela de Bio y Nanotecnologías (EByN), UNSAM, Buenos Aires, Argentina
| | - Virginia Balouz
- Instituto de Investigaciones Biotecnológicas (IIBio), Universidad Nacional de San Martín (UNSAM), and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Escuela de Bio y Nanotecnologías (EByN), UNSAM, Buenos Aires, Argentina
| | - Rosana Lopez
- Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR), Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), and CONICET, Buenos Aires, Argentina
| | - M. Eugenia Giorgi
- Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR), Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), and CONICET, Buenos Aires, Argentina
| | - Carla Marino
- Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR), Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), and CONICET, Buenos Aires, Argentina
| | - Cintia V. Cruz
- Servicio de Parasitología-Chagas, Hospital de Niños ’Dr Ricardo Gutierrez’, and Instituto Multidisciplinario en Investigaciones Pediátricas (IMIPP) CONICET-GCBA, Buenos Aires, Argentina
- Mahidol Oxford Research Unit (MORU), Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Jaime Altcheh
- Servicio de Parasitología-Chagas, Hospital de Niños ’Dr Ricardo Gutierrez’, and Instituto Multidisciplinario en Investigaciones Pediátricas (IMIPP) CONICET-GCBA, Buenos Aires, Argentina
- Fundación para el estudio de las infecciones parasitarias y enfermedad de Chagas (FIPEC foundation), Buenos Aires, Argentina
| | - Carlos A. Buscaglia
- Instituto de Investigaciones Biotecnológicas (IIBio), Universidad Nacional de San Martín (UNSAM), and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Escuela de Bio y Nanotecnologías (EByN), UNSAM, Buenos Aires, Argentina
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