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1. Specificity of serological screening tests and reference laboratory tests to diagnose gambiense human African trypanosomiasis: a prospective clinical performance study

Author

N’Djetchi, Martial Kassi, Camara, Oumou, Koffi, Mathurin, Camara, Mamadou, Kaba, Dramane, Kaboré, Jacques, Tall, Alkali, Rotureau, Brice, Glover, Lucy, Traoré, Mélika Barkissa, Koné, Minayegninrin, Coulibaly, Bamoro, Adingra, Guy Pacome, Soumah, Aissata, Gassama, Mohamed, Camara, Abdoulaye Dansy, Compaoré, Charlie Franck Alfred, Camara, Aïssata, Boiro, Salimatou, Anton, Elena Perez, Bessell, Paul, Van Reet, Nick, Bucheton, Bruno, Jamonneau, Vincent, Bart, Jean-Mathieu, Solano, Philippe, Biéler, Sylvain, and Lejon, Veerle

Published
2024
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6. Low specificity of rapid diagnostic tests and lack of coherence between laboratory tests to diagnose gambiense human African trypanosomiasis, as evidenced by a prospective clinical performance study in Côte d’Ivoire and in Guinea

Author

N’Djetchi, Martial Kassi, primary, Camara, Oumou, additional, Koffi, Mathurin, additional, Camara, Mamadou, additional, Kaba, Dramane, additional, Kaboré, Jacques, additional, Tall, Alkali, additional, Rotureau, Brice, additional, Glover, Lucy, additional, Traoré, Mélika Barkissa, additional, Koné, Minayegninrin, additional, Coulibaly, Bamoro, additional, Adingra, Guy Pacome, additional, Soumah, Aissata, additional, Gassama, Mohamed, additional, Camara, Abdoulaye Dansy, additional, Compaoré, Charlie Franck Alfred, additional, Camara, Aïssata, additional, Boiro, Salimatou, additional, Anton, Elena Perez, additional, Bessell, Paul, additional, Reet, Nick Van, additional, Bucheton, Bruno, additional, Jamonneau, Vincent, additional, Bart, Jean-Mathieu, additional, Solano, Philippe, additional, Biéler, Sylvain, additional, and Lejon, Veerle, additional

Published
2024
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8. Prevalence of dermal trypanosomes in suspected and confirmed cases of gambiense human African trypanosomiasis in Guinea.

Author

Soumah, Alseny M'mah, Camara, Mariame, Kaboré, Justin Windingoudi, Sadissou, Ibrahim, Ilboudo, Hamidou, Travaillé, Christelle, Camara, Oumou, Tichit, Magali, Kaboré, Jacques, Boiro, Salimatou, Crouzols, Aline, Ngoune, Jean Marc Tsagmo, Hardy, David, Camara, Aïssata, Jamonneau, Vincent, MacLeod, Annette, Bart, Jean-Mathieu, Camara, Mamadou, Bucheton, Bruno, and Rotureau, Brice

Subjects
AFRICAN trypanosomiasis, SKIN biopsy, BLOOD testing, TRYPANOSOMA brucei, BLOOD sampling
Abstract

The skin is an anatomical reservoir for African trypanosomes, yet the prevalence of extravascular parasite carriage in the population at risk of gambiense Human African Trypanosomiasis (gHAT) remains unclear. Here, we conducted a prospective observational cohort study in the HAT foci of Forecariah and Boffa, Republic of Guinea. Of the 18,916 subjects serologically screened for gHAT, 96 were enrolled into our study. At enrolment and follow-up visits, participants underwent a dermatological examination and had blood samples and superficial skin snip biopsies taken for examination by molecular and immuno-histological methods. In seropositive individuals, dermatological symptoms were significantly more frequent as compared to seronegative controls. Trypanosoma brucei DNA was detected in the blood of 67% of confirmed cases (22/33) and 9% of unconfirmed seropositive individuals (3/32). However, parasites were detected in the extravascular dermis of up to 71% of confirmed cases (25/35) and 41% of unconfirmed seropositive individuals (13/32) by PCR and/or immuno-histochemistry. Six to twelve months after treatment, trypanosome detection in the skin dropped to 17% of confirmed cases (5/30), whereas up to 25% of unconfirmed, hence untreated, seropositive individuals (4/16) were still found positive. Dermal trypanosomes were observed in subjects from both transmission foci, however, the occurrence of pruritus and the PCR positivity rates were significantly higher in unconfirmed seropositive individuals in Forecariah. The lower sensitivity of superficial skin snip biopsies appeared critical for detecting trypanosomes in the basal dermis. These results are discussed in the context of the planned elimination of gHAT. Author summary: The skin is a reservoir for African trypanosomes. Here, we conducted a prospective study in Forecariah and Boffa, Guinea, to estimate the proportion of skin-dwelling parasites in the population. Of the 18,916 subjects screened for HAT, 96 were enrolled into our study. Participants underwent a dermatological examination and had blood samples and superficial skin biopsies taken for examination by molecular and immuno-histological methods. In individuals seropositive for HAT, dermatological symptoms were significantly more frequent. Trypanosome DNA was detected in the blood of 67% of confirmed cases and 9% of unconfirmed seropositive individuals. However, parasites were detected in the skin of up to 71% of confirmed cases and 41% of unconfirmed seropositive individuals. After treatment, trypanosome detection in the skin dropped to 17% of confirmed cases, whereas up to 25% of unconfirmed, hence untreated, seropositive individuals were still found positive. Dermal trypanosomes were observed in subjects from both regions; however, the occurrence of itching and the PCR positivity were significantly higher in unconfirmed seropositive individuals in Forecariah. The lower sensitivity of superficial skin biopsies appeared critical for detecting trypanosomes. These results are discussed in the context of the planned elimination of HAT. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Specificity of serological screening tests and reference laboratory tests to diagnose gambiense human African trypanosomiasis: a prospective clinical performance study.

Author

N'Djetchi, Martial Kassi, Camara, Oumou, Koffi, Mathurin, Camara, Mamadou, Kaba, Dramane, Kaboré, Jacques, Tall, Alkali, Rotureau, Brice, Glover, Lucy, Traoré, Mélika Barkissa, Koné, Minayegninrin, Coulibaly, Bamoro, Adingra, Guy Pacome, Soumah, Aissata, Gassama, Mohamed, Camara, Abdoulaye Dansy, Compaoré, Charlie Franck Alfred, Camara, Aïssata, Boiro, Salimatou, and Anton, Elena Perez

Subjects
AFRICAN trypanosomiasis, IMMUNOSPECIFICITY, RAPID diagnostic tests, TESTING laboratories, MEDICAL screening
Abstract

Background: Serological screening tests play a crucial role to diagnose gambiense human African trypanosomiasis (gHAT). Presently, they preselect individuals for microscopic confirmation, but in future "screen and treat" strategies they will identify individuals for treatment. Variability in reported specificities, the development of new rapid diagnostic tests (RDT) and the hypothesis that malaria infection may decrease RDT specificity led us to evaluate the specificity of 5 gHAT screening tests. Methods: During active screening, venous blood samples from 1095 individuals from Côte d'Ivoire and Guinea were tested consecutively with commercial (CATT, HAT Sero-K-SeT, Abbott Bioline HAT 2.0) and prototype (DCN HAT RDT, HAT Sero-K-SeT 2.0) gHAT screening tests and with a malaria RDT. Individuals with ≥ 1 positive gHAT screening test underwent microscopy and further immunological (trypanolysis with T.b. gambiense LiTat 1.3, 1.5 and 1.6; indirect ELISA/T.b. gambiense; T.b. gambiense inhibition ELISA with T.b. gambiense LiTat 1.3 and 1.5 VSG) and molecular reference laboratory tests (PCR TBRN3, 18S and TgsGP; SHERLOCK 18S Tids, 7SL Zoon, and TgsGP; Trypanozoon S2-RT-qPCR 18S2, 177T, GPI-PLC and TgsGP in multiplex; RT-qPCR DT8, DT9 and TgsGP in multiplex). Microscopic trypanosome detection confirmed gHAT, while other individuals were considered gHAT free. Differences in fractions between groups were assessed by Chi square and differences in specificity between 2 tests on the same individuals by McNemar. Results: One gHAT case was diagnosed. Overall test specificities (n = 1094) were: CATT 98.9% (95% CI: 98.1–99.4%); HAT Sero-K-SeT 86.7% (95% CI: 84.5–88.5%); Bioline HAT 2.0 82.1% (95% CI: 79.7–84.2%); DCN HAT RDT 78.2% (95% CI: 75.7–80.6%); and HAT Sero-K-SeT 2.0 78.4% (95% CI: 75.9–80.8%). In malaria positives, gHAT screening tests appeared less specific, but the difference was significant only in Guinea for Abbott Bioline HAT 2.0 (P = 0.03) and HAT Sero-K-Set 2.0 (P = 0.0006). The specificities of immunological and molecular laboratory tests in gHAT seropositives were 98.7–100% (n = 399) and 93.0–100% (n = 302), respectively. Among 44 reference laboratory test positives, only the confirmed gHAT patient and one screening test seropositive combined immunological and molecular reference laboratory test positivity. Conclusions: Although a minor effect of malaria cannot be excluded, gHAT RDT specificities are far below the 95% minimal specificity stipulated by the WHO target product profile for a simple diagnostic tool to identify individuals eligible for treatment. Unless specificity is improved, an RDT-based "screen and treat" strategy would result in massive overtreatment. In view of their inconsistent results, additional comparative evaluations of the diagnostic performance of reference laboratory tests are indicated for better identifying, among screening test positives, those at increased suspicion for gHAT. Trial registration: The trial was retrospectively registered under NCT05466630 in clinicaltrials.gov on July 15 2022. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Do Cryptic Reservoirs Threaten Gambiense-Sleeping Sickness Elimination?

Author

Büscher, Philippe, Bart, Jean-Mathieu, Boelaert, Marleen, Bucheton, Bruno, Cecchi, Giuliano, Chitnis, Nakul, Courtin, David, Figueiredo, Luisa M., Franco, José-Ramon, Grébaut, Pascal, Hasker, Epco, Ilboudo, Hamidou, Jamonneau, Vincent, Koffi, Mathurin, Lejon, Veerle, MacLeod, Annette, Masumu, Justin, Matovu, Enock, Mattioli, Raffaele, Noyes, Harry, Picado, Albert, Rock, Kat S., Rotureau, Brice, Simo, Gustave, Thévenon, Sophie, Trindade, Sandra, Truc, Philippe, and Van Reet, Nick

Published
2018
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17. Prevalence of blood and skin trypanosomes in domestic and wild fauna from two sleeping sickness foci in Southern Cameroon

Author

Magang, Eugenie Melaine Kemta, primary, Kamga, Rolin Mitterran Ndefo, additional, Telleria, Jenny, additional, Tichit, Magali, additional, Crouzols, Aline, additional, Kaboré, Jacques, additional, Hardy, David, additional, Bouaka, Calmes Ursain Tsakeng, additional, Jamonneau, Vincent, additional, Rotureau, Brice, additional, Kuete, Victor, additional, Bart, Jean-Mathieu, additional, and Simo, Gustave, additional

Published
2023
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20. Conducting active screening for human African trypanosomiasis with rapid diagnostic tests: The Guinean experience (2016–2021).

Author

Camara, Oumou, Kaboré, Justin Windingoudi, Soumah, Aïssata, Leno, Mamadou, Bangoura, Mohamed Sam, N'Diaye, Dominique, Belem, Adrien Marie Gaston, Biéler, Sylvain, Camara, Mamadou, Bart, Jean-Mathieu, Rotureau, Brice, and Bucheton, Bruno

Subjects
RAPID diagnostic tests, AFRICAN trypanosomiasis, MEDICAL screening, AGGLUTINATION tests
Abstract

Strategies to detect Human African Trypanosomiasis (HAT) cases rely on serological screening of populations exposed to trypanosomes. In Guinea, mass medical screening surveys performed with the Card Agglutination Test for Trypanosomiasis have been progressively replaced by door-to-door approaches using Rapid Diagnostic Tests (RDTs) since 2016. However, RDTs availability represents a major concern and medical teams must often adapt, even in the absence of prior RDT performance evaluation. For the last 5 years, the Guinean HAT National Control Program had to combine three different RDTs according to their availability and price: the SD Bioline HAT (not available anymore), the HAT Sero-K-SeT (most expensive), and recently the Abbott Bioline HAT 2.0 (limited field evaluation). Here, we assess the performance of these RDTs, alone or in different combinations, through the analysis of both prospective and retrospective data. A parallel assessment showed a higher positivity rate of Abbott Bioline HAT 2.0 (6.0%, n = 2,250) as compared to HAT Sero-K-SeT (1.9%), with a combined positive predictive value (PPV) of 20.0%. However, an evaluation of Abbott Bioline HAT 2.0 alone revealed a low PPV of 3.9% (n = 6,930) which was surpassed when using Abbott Bioline HAT 2.0 in first line and HAT Sero-K-SeT as a secondary test before confirmation, with a combined PPV reaching 44.4%. A retrospective evaluation of all 3 RDTs was then conducted on 189 plasma samples from the HAT-NCP biobank, confirming the higher sensitivity (94.0% [85.6–97.7%]) and lower specificity (83.6% [76.0–89.1%]) of Abbott Bioline HAT 2.0 as compared to SD Bioline HAT (Se 64.2% [52.2–74.6%]—Sp 98.4% [94.2–99.5%]) and HAT Sero-K-SeT (Se 88.1% [78.2–93.8%]—Sp 98.4% [94.2–99.5%]). A comparison of Abbott Bioline HAT 2.0 and malaria-RDT positivity rates on 479 subjects living in HAT-free malaria-endemic areas further revealed that a significantly higher proportion of subjects positive in Abbott Bioline HAT 2.0 were also positive in malaria-RDT, suggesting a possible cross-reaction of Abbott Bioline HAT 2.0 with malaria-related biological factors in about 10% of malaria cases. This would explain, at least in part, the limited specificity of Abbott Bioline HAT 2.0. Overall, Abbott Bioline HAT 2.0 seems suitable as first line RDT in combination with a second HAT RDT to prevent confirmatory lab overload and loss of suspects during referral for confirmation. A state-of-the-art prospective comparative study is further required for comparing all current and future HAT RDTs to propose an optimal combination of RDTs for door-to-door active screening. Author summary: Strategies to detect Human African Trypanosomiasis (HAT) cases rely on serological screening of populations exposed to trypanosomes. In Guinea, mass medical screening surveys performed with the Card Agglutination Test for Trypanosomiasis have been progressively replaced by door-to-door approaches using Rapid Diagnostic Tests (RDTs) since 2016. However, RDTs availability represents a major concern and medical teams must often adapt, even in the absence of prior RDT performance evaluation. For the last 5 years, the Guinean HAT National Control Program had to combine three different RDTs according to their availability and price: the SD Bioline HAT (not available anymore), the HAT Sero-K-SeT (most expensive), and recently the Abbott Bioline HAT 2.0 (limited field evaluation). Here, we assess the performance of these RDTs, alone or in different combinations, through the analysis of both prospective and retrospective data. Overall, Abbott Bioline HAT 2.0 seems suitable as first line RDT in combination with a second HAT RDT to prevent confirmatory lab overload and loss of suspects during referral for confirmation. A state-of-the-art prospective comparative study is further required for comparing all current and future HAT RDTs to propose an optimal combination of RDTs for door-to-door active screening. [ABSTRACT FROM AUTHOR]

Published
2024
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22. Confining Trypanosoma brucei in emulsion droplets reveals population variabilities in division rates and improves in vitro cultivation

Author

Allmann, Stefan, Wargnies, Marion, Plazolles, Nicolas, Cahoreau, Edern, Biran, Marc, Morand, Pauline, Pineda, Erika, Kulyk, Hanna, Asencio, Corinne, Villafraz, Oriana, Rivière, Loïc, Tetaud, Emmanuel, Rotureau, Brice, Mourier, Arnaud, Portais, Jean-Charles, Dé Ric Bringaud, Fré, Oldenburg, Simone, Buisson, Lionel, Beneyton, Thomas, Pekin, Deniz, Thonnus, Magali, Bringaud, Frédéric, Baret, Jean-Christophe, Microbiologie Fondamentale et Pathogénicité [Bordeaux] (MFP), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), and Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)

Subjects
Science, Microfluidics, Trypanosoma brucei brucei, Cell, Population, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, Biology, Trypanosoma brucei, 01 natural sciences, Article, 03 medical and health sciences, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, medicine, [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, education, Droplet size, 030304 developmental biology, 0303 health sciences, education.field_of_study, Multidisciplinary, Lab-on-a-chip, Host (biology), 010401 analytical chemistry, Tsetse fly, biology.organism_classification, In vitro, 0104 chemical sciences, Cell biology, Parasite biology, medicine.anatomical_structure, Biological Variation, Population, Medicine, Emulsions, Single-Cell Analysis, Emulsion droplet, Cell Division
Abstract

Trypanosome parasites are infecting mammals in Sub-Saharan Africa and are transmitted between hosts through bites of the tsetse fly. The transmission from the insect vector to the mammal host causes a number of metabolic and physiological changes. A fraction of the population continuously adapt to the immune system of the host, indicating heterogeneity at the population level. Yet, the cell to cell variability in populations is mostly unknown. We develop here an analytical method for quantitative measurements at the single cell level based on encapsulation and cultivation of single-cell Trypanosoma brucei in emulsion droplets. We first show that mammalian stage trypanosomes survive for several hours to days in droplets, with an influence of droplet size on both survival and growth. We unravel various growth patterns within a population and find that droplet cultivation of trypanosomes results in 10-fold higher cell densities of the highest dividing cell variants compared to standard cultivation techniques. Some variants reach final cell titers in droplets closer to what is observed in nature than standard culture, of practical interest for cell production. Droplet microfluidics is therefore a promising tool for trypanosome cultivation and analysis with further potential for high-throughput single cell trypanosome analysis.

Published
2021
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24. VEX1 Influences mVSG Expression During the Transition to Mammalian Infectivity in Trypanosoma brucei

Author

Tihon, Eliane, Rubio-Peña, Karinna, Dujeancourt-Henry, Annick, Crouzols, Aline, Rotureau, Brice, Glover, Lucy, Biologie moléculaire des Trypanosomes - Trypanosome Molecular Biology, Institut Pasteur [Paris] (IP)-Université Paris Cité (UPCité), Biologie cellulaire des Trypanosomes - Trypanosome Cell Biology, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris Cité (UPCité), Institut Pasteur de Guinée, Réseau International des Instituts Pasteur (RIIP), This project has received funding from the Institut Pasteur to LG. ET was supported by funding from the French Government Agence Nationale de la Recherche, ANR-17-CE12-0012 to LG. KR-P is funded by the French Government’s Investissement d’Avenir program Laboratoire d’Excellence Integrative Biology of Emerging Infectious Diseases (grant ANR-10-LABX-62-IBEID)., ANR-17-CE12-0012,VSGREG,Bases moléculaires de la régulation des VSG chez les trypanosomes Africains(2017), ANR-10-LABX-0062,IBEID,Integrative Biology of Emerging Infectious Diseases(2010), Glover, Lucy, Bases moléculaires de la régulation des VSG chez les trypanosomes Africains - - VSGREG2017 - ANR-17-CE12-0012 - AAPG2017 - VALID, and Integrative Biology of Emerging Infectious Diseases - - IBEID2010 - ANR-10-LABX-0062 - LABX - VALID

Subjects
monoallelic expression, VSG, metacyclogenesis, [SDV.BBM] Life Sciences [q-bio]/Biochemistry, Molecular Biology, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Trypanosoma brucei, Cell Biology, antigenic variation, Developmental Biology
Abstract

The Trypanosoma (T) brucei life cycle alternates between the tsetse fly vector and the mammalian host. In the insect, T. brucei undergoes several developmental stages until it reaches the salivary gland and differentiates into the metacyclic form, which is capable of infecting the next mammalian host. Mammalian infectivity is dependent on expression of the metacyclic variant surface glycoprotein genes as the cells develop into mature metacyclics. The VEX complex is essential for monoallelic variant surface glycoprotein expression in T. brucei bloodstream form, however, initiation of expression of the surface proteins genes during metacyclic differentiation is poorly understood. To better understand the transition to mature metacyclics and the control of metacyclic variant surface glycoprotein expression we examined the role of VEX1 in this process. We show that modulating VEX1 expression leads to a dysregulation of variant surface glycoprotein expression during metacyclogenesis, and that following both in vivo and in vitro metacyclic differentiation VEX1 relocalises from multiple nuclear foci in procyclic cells to one to two distinct nuclear foci in metacyclic cells - a pattern like the one seen in mammalian infective bloodstream forms. Our data suggest a role for VEX1 in the metacyclic differentiation process and their capacity to become infectious to the mammalian host.

Published
2022
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25. Extravascular dermal trypanosomes in suspected and confirmed cases of gambiense Human African Trypanosomiasis

Author

Camara, Mariame, Soumah, Alseny M’mah, Ilboudo, Hamidou, Travaillé, Christelle, Clucas, Caroline, Cooper, Anneli, Kuispond Swar, Nono-Raymond, Camara, Oumou, Sadissou, Ibrahim, Calvo Alvarez, Estefania, Crouzols, Aline, Bart, Jean-Mathieu, Jamonneau, Vincent, Camara, Mamadou, MacLeod, Annette, Bucheton, Bruno, Rotureau, Brice, Ministère de la Santé [Conakry, Guinea], Hôpital Donka, Institut de Recherche en Sciences de la Santé [Ouagadougou, Burkina Faso] (IRSS), Institut de Recherche pour le Développement (IRD), Biologie cellulaire des Trypanosomes - Trypanosome Cell Biology, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), College of Medical, Veterinary and Life Sciences [Glasgow], Wellcome Trust Centre for Molecular Parasitology, Institut National de Recherche Biomédicale [Kinshasa] (INRB), Interactions hôtes-vecteurs-parasites-environnement dans les maladies tropicales négligées dues aux trypanosomatides (UMR INTERTRYP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université de Bordeaux (UB), This work was supported by the Wellcome Trust (209511/Z/17/Z), the Institut de Recherche pour le Développement, the Institut Pasteur, the French Government Investissement d'Avenir programme - Laboratoire d'Excellence Integrative Biology of Emerging Infectious Diseases (ANR-10-LABX-62-IBEID) and the French National Agency for Scientific Research (projects ANR-14-CE14-0019-01 EnTrypa and ANR-18-CE15-0012 TrypaDerm)., ANR-10-LABX-0062,IBEID,Integrative Biology of Emerging Infectious Diseases(2010), ANR-14-CE14-0019,ENTRYPA,Dynamique des étapes précoces de l'infection de l'hôte mammifère par les trypanosomes africains(2014), ANR-18-CE15-0012,TrypaDerm,Comprendre la biologie des trypanosomes africains dans la peau(2018), Rotureau, Brice, Integrative Biology of Emerging Infectious Diseases - - IBEID2010 - ANR-10-LABX-0062 - LABX - VALID, Appel à projets générique - Dynamique des étapes précoces de l'infection de l'hôte mammifère par les trypanosomes africains - - ENTRYPA2014 - ANR-14-CE14-0019 - Appel à projets générique - VALID, and APPEL À PROJETS GÉNÉRIQUE 2018 - Comprendre la biologie des trypanosomes africains dans la peau - - TrypaDerm2018 - ANR-18-CE15-0012 - AAPG2018 - VALID

Subjects
reservoir, skin, MESH: Guinea, MESH: Humans, Trypanosoma brucei gambiense, human African trypanosomiasis, [SDV]Life Sciences [q-bio], MESH: Prospective Studies, MESH: Trypanosoma brucei gambiense, [SDV] Life Sciences [q-bio], Major Articles and Commentaries, Trypanosomiasis, African, AcademicSubjects/MED00290, MESH: Trypanosomiasis, African, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Animals, Humans, Guinea, MESH: Animals, [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, Prospective Studies, [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, [SDV.MP.PAR] Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology
Abstract

Background The diagnosis of gambiense human African trypanosomiasis (gHAT) typically involves 2 steps: a serological screen, followed by the detection of living trypanosome parasites in the blood or lymph node aspirate. Live parasites can, however, remain undetected in some seropositive individuals, who, we hypothesize, are infected with Trypanosoma brucei gambiense parasites in their extravascular dermis. Methods To test this hypothesis, we conducted a prospective observational cohort study in the gHAT focus of Forecariah, Republic of Guinea. Of the 5417 subjects serologically screened for gHAT, 66 were enrolled into our study and underwent a dermatological examination. At enrollment, 11 seronegative, 8 unconfirmed seropositive, and 18 confirmed seropositive individuals had blood samples and skin biopsies taken and examined for trypanosomes by molecular and immunohistological methods. Results In seropositive individuals, dermatological symptoms were significantly more frequent, relative to seronegative controls. T.b. gambiense parasites were present in the blood of all confirmed cases (n = 18) but not in unconfirmed seropositive individuals (n = 8). However, T. brucei parasites were detected in the extravascular dermis of all unconfirmed seropositive individuals and all confirmed cases. Skin biopsies of all treated cases and most seropositive untreated individuals progressively became negative for trypanosomes 6 and 20 months later. Conclusions Our results highlight the skin as a potential reservoir for African trypanosomes, with implications for our understanding of this disease’s epidemiology in the context of its planned elimination and underlining the skin as a novel target for gHAT diagnostics., Live trypanosomes can remain undetected in the blood of individuals seropositive for sleeping sickness. Here, we show that they could be infected with parasites in their extravascular dermis, highlighting the skin as a potential reservoir for trypanosomes.

Published
2021
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26. Enhancing research integration to improve One Health actions: learning lessons from neglected tropical diseases experiences

Author

Rotureau, Brice, Waleckx, Etienne, Jamonneau, Vincent, Solano, Philippe, Molia, Sophie, Debré, Patrice, Dellagi, Koussai, Morand, Serge, Rotureau, Brice, Waleckx, Etienne, Jamonneau, Vincent, Solano, Philippe, Molia, Sophie, Debré, Patrice, Dellagi, Koussai, and Morand, Serge

Abstract

Most neglected tropical diseases (NTDs) are intrinsically embedded within the One Health approach: NTD researchers have already been dealing with multidisciplinary and intersectoral work for decades simply because it is essential for understanding and controlling the usually complex transmission of the pathogens causing NTDs. This long experience has already enrooted the idea of the horizontal integration of research, control, elimination and eradication strategies. The ongoing epidemiological transitions of most NTDs urges pursuing and amplifying the development of co-constructed multidisciplinary and intersectoral research initiatives for improving control/elimination/eradication processes. Lessons from NTDs may also be useful for other diseases targeted by ongoing One Health initiatives.

Published
2022

28. Oxidative Phosphorylation Is Required for Powering Motility and Development of the Sleeping Sickness Parasite Trypanosoma brucei in the Tsetse Fly Vector

Author

Dewar, Caroline E., Casas Sanchez, Aitor, Dieme, Constentin, Crouzols, Aline, Haines, Lee, Acosta-Serrano, Alvaro, Rotureau, Brice, Schnaufer, Achim, and Hajduk, Stephen L.

Subjects
qw_51, qx_4, qx_650, wc_705, fungi, qu_450, qx_505, qw_55
Abstract

The single-celled parasite Trypanosoma brucei is transmitted by hematophagous tsetse flies. Life cycle progression from mammalian bloodstream form to tsetse midgut form and, subsequently, infective salivary gland form depends on complex developmental steps and migration within different fly tissues. As the parasite colonizes the glucose-poor insect midgut, ATP production is thought to depend on activation of mitochondrial amino acid catabolism via oxidative phosphorylation (OXPHOS). This process involves respiratory chain complexes and F1Fo-ATP synthase and requires protein subunits of these complexes that are encoded in the parasite's mitochondrial DNA (kDNA). Here, we show that progressive loss of kDNA-encoded functions correlates with a decreasing ability to initiate and complete development in the tsetse. First, parasites with a mutated F1Fo-ATP synthase with reduced capacity for OXPHOS can initiate differentiation from bloodstream to insect form, but they are unable to proliferate in vitro. Unexpectedly, these cells can still colonize the tsetse midgut. However, these parasites exhibit a motility defect and are severely impaired in colonizing or migrating to subsequent tsetse tissues. Second, parasites with a fully disrupted F1Fo-ATP synthase complex that is completely unable to produce ATP by OXPHOS can still differentiate to the first insect stage in vitro but die within a few days and cannot establish a midgut infection in vivo. Third, parasites lacking kDNA entirely can initiate differentiation but die soon after. Together, these scenarios suggest that efficient ATP production via OXPHOS is not essential for initial colonization of the tsetse vector but is required to power trypanosome migration within the fly.\ud \ud IMPORTANCE African trypanosomes cause disease in humans and their livestock and are transmitted by tsetse flies. The insect ingests these parasites with its blood meal, but to be transmitted to another mammal, the trypanosome must undergo complex development within the tsetse fly and migrate from the insect's gut to its salivary glands. Crucially, the parasite must switch from a sugar-based diet while in the mammal to a diet based primarily on amino acids when it develops in the insect. Here, we show that efficient energy production by an organelle called the mitochondrion is critical for the trypanosome's ability to swim and to migrate through the tsetse fly. Surprisingly, trypanosomes with impaired mitochondrial energy production are only mildly compromised in their ability to colonize the tsetse fly midgut. Our study adds a new perspective to the emerging view that infection of tsetse flies by trypanosomes is more complex than previously thought.

Published
2022

31. A multi-adenylate cyclase regulator at the flagellar tip controls African trypanosome transmission

Author

Bachmaier, Sabine, primary, Giacomelli, Giacomo, additional, Calvo-Alvarez, Estéfania, additional, Vieira, Larissa Rezende, additional, Abbeele, Jan Van Den, additional, Aristodemou, Aris, additional, Lorentzen, Esben, additional, Gould, Matthew, additional, Brennand, Ana, additional, Dupuy, Jean-Wiliam, additional, Forné, Ignasi, additional, imhof, Axel, additional, Bramkamp, Marc, additional, Salmon, Didier, additional, Rotureau, Brice, additional, and Boshart, Michael, additional

Published
2022
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33. Des trypanosomes dans la peau

Author

Travaillé, Christelle, Soumah, Alseny M’mah, Ngoune, Jean Marc Tsagmo, Camara, Mariame, Ilboudo, Hamidou, Camara, Oumou, Sadissou, Ibrahim, Bart, Jean-Mathieu, Jamonneau, Vincent, Camara, Mamadou, Bucheton, Bruno, Rotureau, Brice, HORIZON, IRD, Biologie cellulaire des Trypanosomes - Trypanosome Cell Biology, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Ministère de la Santé [Conakry, Guinea], Hôpital National Donka, Interactions hôtes-vecteurs-parasites-environnement dans les maladies tropicales négligées dues aux trypanosomatides (UMR INTERTRYP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université de Bordeaux (UB), Institut Pasteur de Guinée, and Réseau International des Instituts Pasteur (RIIP)

Subjects
réservoir, niche anatomique, [SDV] Life Sciences [q-bio], [SDV.MHEP] Life Sciences [q-bio]/Human health and pathology, peau, [SDV]Life Sciences [q-bio], Trypanosoma brucei gambiense, transmission, [SDV.MHEP]Life Sciences [q-bio]/Human health and pathology, trypanosomiase humaine africaine
Abstract

Le trypanosome africain Trypanosoma brucei gambiense, parasite responsable de la trypanosomiase humaine africaine, est transmis à l'homme par la piqûre d'une mouche tsé-tsé infectée, puis il prolifère dans le sang et la lymphe et enfin dans le système nerveux central. Le diagnostic de trypanosomiase implique deux étapes : un dépistage sérologique suivi de la détection de parasites vivants dans un fluide biologique. Cependant, les parasites peuvent rester indétectables chez certains individus qualifiés de séropositifs non confirmés qui restent alors sans traitement. Dans différents modèles de laboratoire, des chercheurs ont récemment démontré l'existence de réservoirs anatomiques de parasites extravasculaires, en particulier la peau, qui pourraient expliquer les infections latentes. Récemment, la présence de trypanosomes extravasculaires dermiques a également été démontrée chez l'homme, soulignant l'importance des individus séropositifs non confirmés comme réservoir de parasites qui pourrait compromettre l'élimination de la maladie. Les impacts cliniques et épidémiologiques de ces trypanosomes dermiques sont ici discutés.

Published
2021

35. Glycerol suppresses glucose consumption in trypanosomes through metabolic contest

Author

Allmann, Stefan, primary, Wargnies, Marion, additional, Plazolles, Nicolas, additional, Cahoreau, Edern, additional, Biran, Marc, additional, Morand, Pauline, additional, Pineda, Erika, additional, Kulyk, Hanna, additional, Asencio, Corinne, additional, Villafraz, Oriana, additional, Rivière, Loïc, additional, Tetaud, Emmanuel, additional, Rotureau, Brice, additional, Mourier, Arnaud, additional, Portais, Jean-Charles, additional, and Bringaud, Frédéric, additional

Published
2021
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36. Practices in research, surveillance and control of neglected tropical diseases by One Health approaches: A survey targeting scientists from French-speaking countries

Author

Molia, Sophie, Saillard, Juliette, Dellagi, Koussai, Cliquet, Florence, Bart, Jean-Mathieu, Rotureau, Brice, Giraudoux, Patrick, Jannin, Jean, Debré, Patrice, Solano, Philippe, Molia, Sophie, Saillard, Juliette, Dellagi, Koussai, Cliquet, Florence, Bart, Jean-Mathieu, Rotureau, Brice, Giraudoux, Patrick, Jannin, Jean, Debré, Patrice, and Solano, Philippe

Abstract

One health (OH) approaches have increasingly been used in the last decade in the fight against zoonotic neglected tropical diseases (NTDs). However, descriptions of such collaborations between the human, animal and environmental health sectors are still limited for French-speaking tropical countries. The objective of the current survey was to explore the diversity of OH experiences applied to research, surveillance and control of NTDs by scientists from French-speaking countries, and discuss their constraints and benefits. Six zoonotic NTDs were targeted: echinococcoses, trypanosomiases, leishmaniases, rabies, Taenia solium cysticercosis and leptospiroses. Invitations to fill in an online questionnaire were sent to members of francophone networks on NTDs and other tropical diseases. Results from the questionnaire were discussed during an international workshop in October 2019. The vast majority (98%) of the 171 respondents considered OH approaches relevant although only 64% had implemented them. Among respondents with OH experience, 58% had encountered difficulties mainly related to a lack of knowledge, interest and support for OH approaches by funding agencies, policy-makers, communities and researchers. Silos between disciplines and health sectors were still strong at both scientific and operational levels. Benefits were reported by 94% of respondents with OH experience, including increased intellectual stimulation, stronger collaborations, higher impact and cost-efficiency of interventions. Recommendations for OH uptake included advocacy, capacity-building, dedicated funding, and higher communities' involvement. Improved research coordination by NTD networks, production of combined human-animal health NTD impact indicators, and transversal research projects on diagnostic and reservoirs were also considered essential.

Published
2021

37. Redistribution of FLAgellar Member 8 during the trypanosome life cycle:Consequences for cell fate prediction

Author

Calvo-Álvarez, Estefanía, Bonnefoy, Serge, Salles, Audrey, Benson, Fiona E, McKean, Paul G, Bastin, Philippe, Rotureau, Brice, Calvo-Álvarez, Estefanía, Bonnefoy, Serge, Salles, Audrey, Benson, Fiona E, McKean, Paul G, Bastin, Philippe, and Rotureau, Brice

Abstract

The single flagellum of African trypanosomes is essential in multiple aspects of the parasites' development. The FLAgellar Member 8 protein (FLAM8), localised to the tip of the flagellum in cultured insect forms of Trypanosoma brucei, was identified as a marker of the locking event that controls flagellum length. Here, we investigated whether FLAM8 could also reflect the flagellum maturation state in other parasite cycle stages. We observed that FLAM8 distribution extended along the entire flagellar cytoskeleton in mammalian-infective forms. Then, a rapid FLAM8 concentration to the distal tip occurs during differentiation into early insect forms, illustrating the remodelling of an existing flagellum. In the tsetse cardia, FLAM8 further localises to the entire length of the new flagellum during an asymmetric division. Strikingly, in parasites dividing in the tsetse midgut and in the salivary glands, the amount and distribution of FLAM8 in the new flagellum were seen to predict the daughter cell fate. We propose and discuss how FLAM8 could be considered a meta-marker of the flagellum stage and maturation state in trypanosomes.

Published
2021

38. Redistribution of FLAgellar Member 8 during the trypanosome life cycle : Consequences for cell fate prediction

Author

Calvo-Álvarez, Estefanía, Bonnefoy, Serge, Salles, Audrey, Benson, Fiona E, McKean, Paul G, Bastin, Philippe, Rotureau, Brice, Calvo-Álvarez, Estefanía, Bonnefoy, Serge, Salles, Audrey, Benson, Fiona E, McKean, Paul G, Bastin, Philippe, and Rotureau, Brice

Abstract

The single flagellum of African trypanosomes is essential in multiple aspects of the parasites' development. The FLAgellar Member 8 protein (FLAM8), localised to the tip of the flagellum in cultured insect forms of Trypanosoma brucei, was identified as a marker of the locking event that controls flagellum length. Here, we investigated whether FLAM8 could also reflect the flagellum maturation state in other parasite cycle stages. We observed that FLAM8 distribution extended along the entire flagellar cytoskeleton in mammalian-infective forms. Then, a rapid FLAM8 concentration to the distal tip occurs during differentiation into early insect forms, illustrating the remodelling of an existing flagellum. In the tsetse cardia, FLAM8 further localises to the entire length of the new flagellum during an asymmetric division. Strikingly, in parasites dividing in the tsetse midgut and in the salivary glands, the amount and distribution of FLAM8 in the new flagellum were seen to predict the daughter cell fate. We propose and discuss how FLAM8 could be considered a meta-marker of the flagellum stage and maturation state in trypanosomes.

Published
2021

43. Practices in research, surveillance and control of neglected tropical diseases by One Health approaches: A survey targeting scientists from French-speaking countries

Author

Molia, Sophie, primary, Saillard, Juliette, additional, Dellagi, Koussai, additional, Cliquet, Florence, additional, Bart, Jean-Mathieu, additional, Rotureau, Brice, additional, Giraudoux, Patrick, additional, Jannin, Jean, additional, Debré, Patrice, additional, and Solano, Philippe, additional

Published
2021
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47. Extravascular Dermal Trypanosomes in Suspected and Confirmed Cases of gambiense Human African Trypanosomiasis

Author

Camara, Mariame, primary, Soumah, Alseny M’mah, additional, Ilboudo, Hamidou, additional, Travaillé, Christelle, additional, Clucas, Caroline, additional, Cooper, Anneli, additional, Kuispond Swar, Nono-Raymond, additional, Camara, Oumou, additional, Sadissou, Ibrahim, additional, Calvo Alvarez, Estefania, additional, Crouzols, Aline, additional, Bart, Jean-Mathieu, additional, Jamonneau, Vincent, additional, Camara, Mamadou, additional, MacLeod, Annette, additional, Bucheton, Bruno, additional, and Rotureau, Brice, additional

Published
2020
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49. Gluconeogenesis is essential for trypanosome development in the tsetse fly vector

Author

Wargnies, Marion, Bertiaux, Eloise, Cahoreau, Edern, Ziebart, Nicole, Crouzols, Aline, Morand, Pauline, Biran, Marc, Allmann, Stefan, Hubert, Jane, Villafraz, Oriana, Millerioux, Yoann, Plazolles, Nicolas, Asencio, Corinne, Rivière, Loïc, Rotureau, Brice, Boshart, Michael, Portais, Jean-Charles, Bringaud, Frédéric, Microbiologie Fondamentale et Pathogénicité (MFP), Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique (CNRS), Centre de résonance magnétique des systèmes biologiques (CRMSB), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Biologie cellulaire des Trypanosomes - Trypanosome Cell Biology, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), MetaToul FluxoMet (TBI-MetaToul), MetaboHUB-MetaToul, MetaboHUB-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-MetaboHUB-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Ludwig-Maximilians-Universität München (LMU), The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. FB's and BR's group were funded by the Agence Nationale de la Recherche (ANR) through GLYCONOV (grant number ANR-15-CE15-0025-01) of the ANR-BLANC-2015 call. FB's group was supported by the Centre National de la Recherche Scientifique (CNRS), the Université de Bordeaux, the ANR through the grants ACETOTRYP (grant number ANR-2010-BLAN-1319-02) of the ANR-BLANC-2010 call, the Laboratoire d’Excellence (LabEx) ParaFrap ANR-11-LABX-0024 and the ParaMet PhD programme of Marie Curie Initial Training Network. BR’s group was supported by the Institut Pasteur, the Institut National de la Santé et de la Recherche Médicale (INSERM). EB is funded by a doctoral fellowship from French National Ministry for Research and Technology (Doctoral School CDV515). MB was funded by the University of Munich and MB and FB were supported by a research cooperation grant of the Franco-Bavarian University Cooperation Center (BFHZ/CCUFB)., ANR-15-CE15-0025,GLYCONOV,Voies métaboliques glycosomales non glycolytiques: nouvelles fonctions pour le développement et la virulence des trypanosomes(2015), ANR-10-BLAN-1319,ACETOTRYP,Metabolisme de l'acetyl-CoA et de l'acetate chez les trypanosomes: identification de nouvelles voies métaboliques spécifiques aux parasites(2010), ANR-11-LABX-0024,ParaFrap,Alliance française contre les maladies parasitaires(2011), Microbiologie cellulaire et moléculaire et pathogénicité (MCMP), Résonance magnétique des systèmes biologiques (RMSB), Biologie cellulaire des Trypanosomes, Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Rotureau, Brice, Voies métaboliques glycosomales non glycolytiques: nouvelles fonctions pour le développement et la virulence des trypanosomes - - GLYCONOV2015 - ANR-15-CE15-0025 - AAPG2015 - VALID, BLANC - Metabolisme de l'acetyl-CoA et de l'acetate chez les trypanosomes: identification de nouvelles voies métaboliques spécifiques aux parasites - - ACETOTRYP2010 - ANR-10-BLAN-1319 - BLANC - VALID, and Laboratoires d'excellence - Alliance française contre les maladies parasitaires - - ParaFrap2011 - ANR-11-LABX-0024 - LABX - VALID

Subjects
Glycerol, gène codant, Disease Vectors, Biochemistry, Salivary Glands, Glucose Metabolism, Medicine and Health Sciences, Biology (General), Amino Acids, Protozoans, surexpression, Organic Compounds, Microbiology and Parasitology, Monosaccharides, Monomers, Eukaryota, Microbiologie et Parasitologie, Chemistry, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, protéine, Physical Sciences, Carbohydrate Metabolism, Anatomy, [SDV.MP.PAR] Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, Research Article, Trypanosoma, Tsetse Flies, Proline, QH301-705.5, Trypanosoma brucei brucei, Carbohydrates, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Phosphates, Exocrine Glands, Parasitic Diseases, Animals, [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, gluconeogénèse, Organic Chemistry, Gluconeogenesis, Organisms, Chemical Compounds, Biology and Life Sciences, Proteins, Cyclic Amino Acids, RC581-607, mouche tsé tsé, Polymer Chemistry, Parasitic Protozoans, enzyme, Trypanosomiasis, African, Metabolism, Glucose, Immunologic diseases. Allergy, Digestive System, trypanosoma brucei
Abstract

In the glucose-free environment that is the midgut of the tsetse fly vector, the procyclic form of Trypanosoma brucei primarily uses proline to feed its central carbon and energy metabolism. In these conditions, the parasite needs to produce glucose 6-phosphate (G6P) through gluconeogenesis from metabolism of non-glycolytic carbon source(s). We showed here that two phosphoenolpyruvate-producing enzymes, PEP carboxykinase (PEPCK) and pyruvate phosphate dikinase (PPDK) have a redundant function for the essential gluconeogenesis from proline. Indeed, incorporation of 13C-enriched proline into G6P was abolished in the PEPCK/PPDK null double mutant (Δppdk/Δpepck), but not in the single Δppdk and Δpepck mutant cell lines. The procyclic trypanosome also uses the glycerol conversion pathway to feed gluconeogenesis, since the death of the Δppdk/Δpepck double null mutant in glucose-free conditions is only observed after RNAi-mediated down-regulation of the expression of the glycerol kinase, the first enzyme of the glycerol conversion pathways. Deletion of the gene encoding fructose-1,6-bisphosphatase (Δfbpase), a key gluconeogenic enzyme irreversibly producing fructose 6-phosphate from fructose 1,6-bisphosphate, considerably reduced, but not abolished, incorporation of 13C-enriched proline into G6P. In addition, the Δfbpase cell line is viable in glucose-free conditions, suggesting that an alternative pathway can be used for G6P production in vitro. However, FBPase is essential in vivo, as shown by the incapacity of the Δfbpase null mutant to colonise the fly vector salivary glands, while the parental phenotype is restored in the Δfbpase rescued cell line re-expressing FBPase. The essential role of FBPase for the development of T. brucei in the tsetse was confirmed by taking advantage of an in vitro differentiation assay based on the RNA-binding protein 6 over-expression, in which the procyclic forms differentiate into epimastigote forms but not into mammalian-infective metacyclic parasites. In total, morphology, immunofluorescence and cytometry analyses showed that the differentiation of the epimastigote stages into the metacyclic forms is abolished in the Δfbpase mutant., Author summary Trypanosoma brucei, the parasite responsible for sleeping sickness in humans, is transmitted by the tsetse fly that primarily uses amino acids for its energy production. In the glucose-free environment encountered between the insect blood meals, T. brucei needs to produce through gluconeogenesis glucose 6-phosphate, a key precursor for several essential metabolic pathways. We have shown here that two key gluconeogenic steps, which produce phosphoenolpyruvate and fructose 6-phosphate, respectively, are performed by redundant enzymes (PPDK and PEPCK for phosphoenolpyruvate production; FBPase and a yet unknown enzyme for fructose 6-phosphate production), which highlights the importance of this metabolic pathway for the insect stages of the parasite. Interestingly, deletion of the parasite FBPase gene abolished both the colonisation of the insect salivary glands and the in vitro differentiation of the epimastigote forms into the mammalian infective form of the parasite. Altogether, these data demonstrate for the first time that gluconeogenesis is essential for development of T. brucei in its insect vector and that early development stages of the parasite present in the tsetse midgut are not affected by the absence of FBPase, probably by developing an alternative yet unknown approach to produce fructose 6-phosphate.

Published
2018
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50. De novo biosynthesis of sterols and fatty acids in the Trypanosoma brucei procyclic form: Carbon source preferences and metabolic flux redistributions

Author

Millerioux, Yoann, Mazet, Muriel, Bouyssou, Guillaume, Allmann, Stefan, Kiema, Tiila-Riikka, Bertiaux, Eloise, Fouillen, Laetitia, Thapa, Chandan, Biran, Marc, Plazolles, Nicolas, Dittrich-Domergue, Franziska, Crouzols, Aline, Wierenga, Rik, Rotureau, Brice, MOREAU, Patrick, Bringaud, Frédéric, Microbiologie Fondamentale et Pathogénicité (MFP), Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique (CNRS), Centre de résonance magnétique des systèmes biologiques (CRMSB), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de biogenèse membranaire (LBM), University of Oulu, Biologie cellulaire des Trypanosomes - Trypanosome Cell Biology, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), This research was supported by the Centre National de la Recherche Scientifique (CNRS), the Université de Bordeaux, the Agence Nationale de la Recherche (ANR) through grants ACETOTRYP (grant number ANR-2010-BLAN-1319-02) of the ANR-BLANC-2010 call and GLYCONOV (grant number ANR-15-CE15-0025-01) of the 'Générique' 2015 call, the Laboratoire d’Excellence (LabEx) ParaFrap (grant number ANR-11-LABX-0024), the Institut Pasteur and by the European Commission FP7 Marie Curie Initial Training Network 'ParaMet' (grant number 290080). EB was funded by a doctoral fellowship from French National Ministry for Research and Technology (doctoral school CDV515)., ANR-10-BLAN-1319,ACETOTRYP,Metabolisme de l'acetyl-CoA et de l'acetate chez les trypanosomes: identification de nouvelles voies métaboliques spécifiques aux parasites(2010), ANR-11-LABX-0024,ParaFrap,Alliance française contre les maladies parasitaires(2011), European Project: 290080,EC:FP7:PEOPLE,FP7-PEOPLE-2011-ITN,PARAMET(2012), Résonance magnétique des systèmes biologiques (RMSB), Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université d'Auvergne - Clermont-Ferrand I (UdA)-Centre National de la Recherche Scientifique (CNRS), Microbiologie cellulaire et moléculaire et pathogénicité (MCMP), Biologie cellulaire des Trypanosomes, Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Rotureau, Brice, BLANC - Metabolisme de l'acetyl-CoA et de l'acetate chez les trypanosomes: identification de nouvelles voies métaboliques spécifiques aux parasites - - ACETOTRYP2010 - ANR-10-BLAN-1319 - BLANC - VALID, Laboratoires d'excellence - Alliance française contre les maladies parasitaires - - ParaFrap2011 - ANR-11-LABX-0024 - LABX - VALID, and A systematic analysis of parasite metabolism - from metabolism to intervention - PARAMET - - EC:FP7:PEOPLE2012-06-01 - 2016-05-31 - 290080 - VALID

Subjects
Threonine, [SDV]Life Sciences [q-bio], blood-sream forms, Acetates, Biochemistry, molecular characterization, Gene Knockout Techniques, dependent enzyme, Glucose Metabolism, proline metabolism, MESH: Animals, Amino Acids, MESH: Threonine, lcsh:QH301-705.5, MESH: Gene Knockout Techniques, Protozoans, MESH: Tsetse Flies, Organic Compounds, Fatty Acids, Monosaccharides, Eukaryota, cell-cycle, acetyl-coa, energy-metabolism, lipbiosyntesis, leishmania-mexicana, succinate coa-transferase, MESH: Mevalonic Acid, Lipids, MESH: Gene Expression Regulation, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM], MESH: Fatty Acids, [SDV] Life Sciences [q-bio], MESH: Glucose, Sterols, Chemistry, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Physical Sciences, Carbohydrate Metabolism, MESH: Acetates, [SDV.MP.PAR] Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, Research Article, lcsh:Immunologic diseases. Allergy, Trypanosoma, Proline, Tsetse Flies, Trypanosoma brucei brucei, Carbohydrates, Mevalonic Acid, MESH: Carbon, MESH: Insect Vectors, Biosynthesis, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, MESH: Alcohol Oxidoreductases, Acetyl Coenzyme A, Acetyltransferases, Leucine, Hydroxyl Amino Acids, MESH: Acyl Coenzyme A, Animals, [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, MESH: Proline, Organic Chemistry, Organisms, Chemical Compounds, Biology and Life Sciences, Proteins, MESH: Trypanosoma brucei brucei, MESH: Acetyltransferases, Carbon, Parasitic Protozoans, Insect Vectors, Alcohol Oxidoreductases, Glucose, Metabolism, MESH: Leucine, Gene Expression Regulation, Aliphatic Amino Acids, lcsh:Biology (General), MESH: Sterols, Acyl Coenzyme A, lcsh:RC581-607, MESH: Acetyl Coenzyme A
Abstract

De novo biosynthesis of lipids is essential for Trypanosoma brucei, a protist responsible for the sleeping sickness. Here, we demonstrate that the ketogenic carbon sources, threonine, acetate and glucose, are precursors for both fatty acid and sterol synthesis, while leucine only contributes to sterol production in the tsetse fly midgut stage of the parasite. Degradation of these carbon sources into lipids was investigated using a combination of reverse genetics and analysis of radio-labelled precursors incorporation into lipids. For instance, (i) deletion of the gene encoding isovaleryl-CoA dehydrogenase, involved in the leucine degradation pathway, abolished leucine incorporation into sterols, and (ii) RNAi-mediated down-regulation of the SCP2-thiolase gene expression abolished incorporation of the three ketogenic carbon sources into sterols. The SCP2-thiolase is part of a unidirectional two-step bridge between the fatty acid precursor, acetyl-CoA, and the precursor of the mevalonate pathway leading to sterol biosynthesis, 3-hydroxy-3-methylglutaryl-CoA. Metabolic flux through this bridge is increased either in the isovaleryl-CoA dehydrogenase null mutant or when the degradation of the ketogenic carbon sources is affected. We also observed a preference for fatty acids synthesis from ketogenic carbon sources, since blocking acetyl-CoA production from both glucose and threonine abolished acetate incorporation into sterols, while incorporation of acetate into fatty acids was increased. Interestingly, the growth of the isovaleryl-CoA dehydrogenase null mutant, but not that of the parental cells, is interrupted in the absence of ketogenic carbon sources, including lipids, which demonstrates the essential role of the mevalonate pathway. We concluded that procyclic trypanosomes have a strong preference for fatty acid versus sterol biosynthesis from ketogenic carbon sources, and as a consequence, that leucine is likely to be the main source, if not the only one, used by trypanosomes in the infected insect vector digestive tract to feed the mevalonate pathway., Author summary In this study, we have (i) determined the carbon sources used by the Trypanosoma brucei procyclic insect form to feed the essential lipid biosynthetic pathways, (ii) further characterized the metabolic pathways leading to their degradation into acetyl-CoA (fatty acid precursor) and 3-hydroxy-3-methylglutaryl-CoA (sterol precursor) and (iii) showed that reduction of the ketogenic carbon sources degradation, favors their incorporation into fatty acids, instead of sterols. This fatty acid preference is compensated by an increase of leucine incorporation into sterols, which highlights the parasite adaptation capacity regarding carbon source availability by modulating the metabolic flux between branches within the network. This metabolic flexibility is particularly relevant for the insect stages of trypanosomes that evolve in the midgut and the salivary glands of their blood-feeding insect vector. One may also consider that, the metabolic flow redistribution towards the mevalonate pathway (sterol production) described in vitro also occurs in vivo, depending on the carbon source composition of the tsetse fly micro-environment, which may considerably vary along the digestive tract and depending on the fly feeding status, as well as in the other infected fly organs.

Published
2018
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