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  1. Article ; Online: Methods to Investigate Signal Transduction Pathways in Trypanosoma cruzi: Cyclic Nucleotide Phosphodiesterases Assay Protocols.

    Schoijet, Alejandra C / Sternlieb, Tamara / Alonso, Guillermo D

    Methods in molecular biology (Clifton, N.J.)

    2020  Volume 2116, Page(s) 523–534

    Abstract: Intracellular levels of cyclic nucleotide second messengers are regulated predominantly by a large superfamily of phosphodiesterases (PDEs). Most of the different PDE variants play specific physiological functions; in fact, PDEs can associate with other ... ...

    Abstract Intracellular levels of cyclic nucleotide second messengers are regulated predominantly by a large superfamily of phosphodiesterases (PDEs). Most of the different PDE variants play specific physiological functions; in fact, PDEs can associate with other proteins allowing them to be strategically anchored throughout the cell. In this regard, precise cellular expression and compartmentalization of these enzymes produce the specific control of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) gradients in cells and enable their integration with other signaling pathways.In trypanosomatids, some PDEs are essential for their survival and play fundamental roles in the adaptation of these parasites to different environmental stresses, as well as in the differentiation between their different life cycle forms. Given that these enzymes not only are similar to human PDEs but also have differential biochemical properties, and due to the great knowledge of drugs that target human PDEs, trypanosomatid PDEs could be postulated as important therapeutic targets through the repositioning of drugs.In this chapter, we describe a simple and sensitive radioisotope-based method to measure cyclic 3',5'-nucleotide phosphodiesterase using [
    MeSH term(s) 3',5'-Cyclic-AMP Phosphodiesterases/chemistry ; 3',5'-Cyclic-AMP Phosphodiesterases/isolation & purification ; 3',5'-Cyclic-AMP Phosphodiesterases/metabolism ; Cyclic AMP/chemistry ; Cyclic AMP/metabolism ; Enzyme Assays/methods ; Isotope Labeling/methods ; Life Cycle Stages ; Protozoan Proteins/chemistry ; Protozoan Proteins/isolation & purification ; Protozoan Proteins/metabolism ; Signal Transduction ; Tritium/chemistry ; Trypanosoma cruzi/metabolism
    Chemical Substances Protozoan Proteins ; Tritium (10028-17-8) ; Cyclic AMP (E0399OZS9N) ; 3',5'-Cyclic-AMP Phosphodiesterases (EC 3.1.4.17)
    Language English
    Publishing date 2020-03-27
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1940-6029
    ISSN (online) 1940-6029
    DOI 10.1007/978-1-0716-0294-2_31
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  2. Article: Intracellular cyclic AMP levels modulate differential adaptive responses on epimastigotes and cell culture trypomastigotes of Trypanosoma cruzi

    Sternlieb, Tamara / Schoijet, Alejandra C / Alonso, Guillermo D

    Acta tropica. 2020 Feb., v. 202

    2020  

    Abstract: Among the many environmental challenges the parasite Trypanosoma cruzi has to overcome to complete its life cycle through different hosts, oxidative stress plays a central role. Different stages of this parasite encounter distinct sources of oxidative ... ...

    Abstract Among the many environmental challenges the parasite Trypanosoma cruzi has to overcome to complete its life cycle through different hosts, oxidative stress plays a central role. Different stages of this parasite encounter distinct sources of oxidative stress, such as the oxidative burst of the immune system, or the Heme released from hemoglobin degradation in the triatomine's midgut. Also, the redox status of the surroundings functions as a signal to the parasite, triggering processes coupled to differentiation or proliferation. Intracellular second messengers, like cAMP, are responsible for the transduction of environmental queues and initiating cellular processes accordingly. In trypanosomatids cAMP is involved in a variety of processes, including proliferation, differentiation, osmoregulation and quorum sensing. Trypanosomatid phosphodiesterases (PDE) show atypical pharmacological properties and some have been involved in key processes for the survival of the parasites, which validates them as attractive therapeutic targets. Our work here shows that cAMP modulates different processes according to parasite stage. Epimastigotes become more resistant to oxidative stress when pre-treated with cAMP analogs, while in trypomastigotes an increase in intracellular cAMP doesn't seem to aid in this response, although it does increase the number of amastigotes obtained 48 h after infection, compared to the control group. Also, we show that TcrPDEA1, a functionally enigmatic phosphodiesterase with very high Km, is involved in the epimastigotes response to oxidative stress.
    Keywords Triatominae ; Trypanosoma cruzi ; amastigotes ; cell culture ; cyclic AMP ; enzymes ; epimastigotes ; heme ; hemoglobin ; hosts ; immune system ; medicinal properties ; midgut ; osmoregulation ; oxidative stress ; parasites ; quorum sensing ; second messengers ; therapeutics ; trypomastigotes
    Language English
    Dates of publication 2020-02
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 210415-5
    ISSN 1873-6254 ; 0001-706X
    ISSN (online) 1873-6254
    ISSN 0001-706X
    DOI 10.1016/j.actatropica.2019.105273
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  3. Article ; Online: Intracellular cyclic AMP levels modulate differential adaptive responses on epimastigotes and cell culture trypomastigotes of Trypanosoma cruzi.

    Sternlieb, Tamara / Schoijet, Alejandra C / Alonso, Guillermo D

    Acta tropica

    2019  Volume 202, Page(s) 105273

    Abstract: Among the many environmental challenges the parasite Trypanosoma cruzi has to overcome to complete its life cycle through different hosts, oxidative stress plays a central role. Different stages of this parasite encounter distinct sources of oxidative ... ...

    Abstract Among the many environmental challenges the parasite Trypanosoma cruzi has to overcome to complete its life cycle through different hosts, oxidative stress plays a central role. Different stages of this parasite encounter distinct sources of oxidative stress, such as the oxidative burst of the immune system, or the Heme released from hemoglobin degradation in the triatomine's midgut. Also, the redox status of the surroundings functions as a signal to the parasite, triggering processes coupled to differentiation or proliferation. Intracellular second messengers, like cAMP, are responsible for the transduction of environmental queues and initiating cellular processes accordingly. In trypanosomatids cAMP is involved in a variety of processes, including proliferation, differentiation, osmoregulation and quorum sensing. Trypanosomatid phosphodiesterases (PDE) show atypical pharmacological properties and some have been involved in key processes for the survival of the parasites, which validates them as attractive therapeutic targets. Our work here shows that cAMP modulates different processes according to parasite stage. Epimastigotes become more resistant to oxidative stress when pre-treated with cAMP analogs, while in trypomastigotes an increase in intracellular cAMP doesn't seem to aid in this response, although it does increase the number of amastigotes obtained 48 h after infection, compared to the control group. Also, we show that TcrPDEA1, a functionally enigmatic phosphodiesterase with very high Km, is involved in the epimastigotes response to oxidative stress.
    MeSH term(s) Animals ; Chlorocebus aethiops ; Cyclic AMP/metabolism ; Cytoplasm/metabolism ; Life Cycle Stages ; Oxidation-Reduction ; Trypanosoma cruzi/physiology ; Vero Cells
    Chemical Substances Cyclic AMP (E0399OZS9N)
    Language English
    Publishing date 2019-11-14
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 210415-5
    ISSN 1873-6254 ; 0001-706X
    ISSN (online) 1873-6254
    ISSN 0001-706X
    DOI 10.1016/j.actatropica.2019.105273
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: An AMP-activated protein kinase complex with two distinctive alpha subunits is involved in nutritional stress responses in Trypanosoma cruzi.

    Sternlieb, Tamara / Schoijet, Alejandra C / Genta, Patricio D / Vilchez Larrea, Salomé C / Alonso, Guillermo D

    PLoS neglected tropical diseases

    2021  Volume 15, Issue 5, Page(s) e0009435

    Abstract: Trypanosoma cruzi, the etiological agent of Chagas disease, has a digenetic life cycle. In its passage from the insect vector to the mammalian host, and vice versa, it must be prepared to cope with abrupt changes in environmental conditions, such as ... ...

    Abstract Trypanosoma cruzi, the etiological agent of Chagas disease, has a digenetic life cycle. In its passage from the insect vector to the mammalian host, and vice versa, it must be prepared to cope with abrupt changes in environmental conditions, such as carbon source, pH, temperature and osmolarity, in order to survive. Sensing and signaling pathways that allow the parasite to adapt, have unique characteristics with respect to their hosts and other free-living organisms. Many of the canonical proteins involved in these transduction pathways have not yet been found in the genomes of these parasites because they present divergences either at the functional, structural and/or protein sequence level. All of this makes these pathways promising targets for therapeutic drugs. The AMP-activated protein kinase (AMPK) is a serine/threonine kinase activated by environmental stresses such as osmotic stress, hypoxia, ischaemia and exercise that results in reduction of ATP and increase of AMP levels. Thus, AMPK is regarded as a fuel gauge, functioning both as a nutrient and an energy sensor, to maintain energy homeostasis and, eventually, to protect cells from death by nutrient starvation. In the present study we report the characterization of AMPK complexes for the first time in T. cruzi and propose the function of TcAMPK as a novel regulator of nutritional stress in epimastigote forms. We show that there is phosphotransferase activity specific for SAMS peptide in epimastigotes extracts, which is inhibited by Compound C and is modulated by carbon source availability. In addition, TcAMPKα2 subunit has an unprecedented functional substitution (Ser x Thr) at the activation loop and its overexpression in epimastigotes led to higher autophagic activity during prolonged nutritional stress. Moreover, the over-expression of the catalytic subunits resulted in antagonistic phenotypes associated with proliferation. Together, these results point to a role of TcAMPK in autophagy and nutrient sensing, key processes for the survival of trypanosomatids and for its life cycle progression.
    MeSH term(s) AMP-Activated Protein Kinases/chemistry ; AMP-Activated Protein Kinases/genetics ; AMP-Activated Protein Kinases/metabolism ; Autophagy ; Energy Metabolism ; Protein-Serine-Threonine Kinases/metabolism ; Pyrazoles/pharmacology ; Pyrimidines/pharmacology ; Saccharomyces cerevisiae/genetics ; Saccharomyces cerevisiae/metabolism ; Signal Transduction ; Stress, Physiological ; Trypanosoma cruzi/enzymology ; Trypanosoma cruzi/growth & development ; Trypanosoma cruzi/metabolism
    Chemical Substances Pyrazoles ; Pyrimidines ; dorsomorphin (10K52CIC1Z) ; Protein-Serine-Threonine Kinases (EC 2.7.11.1) ; AMP-Activated Protein Kinases (EC 2.7.11.31)
    Language English
    Publishing date 2021-05-24
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2429704-5
    ISSN 1935-2735 ; 1935-2727
    ISSN (online) 1935-2735
    ISSN 1935-2727
    DOI 10.1371/journal.pntd.0009435
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: The Phosphatidylinositol 3-kinase Class III Complex Containing TcVps15 and TcVps34 Participates in Autophagy in Trypanosoma cruzi.

    Schoijet, Alejandra C / Sternlieb, Tamara / Alonso, Guillermo D

    The Journal of eukaryotic microbiology

    2017  Volume 64, Issue 3, Page(s) 308–321

    Abstract: Autophagy is a degradative process by which eukaryotic cells digest their own components to provide aminoacids that may function as energy source under nutritional stress conditions. There is experimental evidence for autophagy in parasitic protists ... ...

    Abstract Autophagy is a degradative process by which eukaryotic cells digest their own components to provide aminoacids that may function as energy source under nutritional stress conditions. There is experimental evidence for autophagy in parasitic protists belonging to the family Trypanosomatidae. However, few proteins implicated in this process have been characterized so far in these parasites. Moreover, it has been shown that autophagy is involved in Trypanosoma cruzi differentiation and thus might have a role in pathogenicity. Here, we report the cloning and biochemical characterization of TcVps15. In addition, we demonstrate that TcVps15 interact with the PI3K TcVps34 and that both proteins associate with cellular membranes. Under nutritional stress conditions, TcVps15 and TcVps34 modify their subcellular distribution showing a partial co-localization in autophagosomes with TcAtg8.1 and using an active site TcVps15-mutated version (TcVps15-K219D-HA) we demonstrated that this relocalization depends on the TcVps15 catalytic activity. Overexpression of TcVps15-HA and TcVps15-K219D-HA also leads to increased accumulation of monodansylcadaverine (MDC) in autophagic vacuoles under nutritional stress conditions compared to wild-type cells. In addition, the MDC-specific activity shows to be significantly higher in TcVps15-HA overexpressing cells when compared with TcVps15-K219D-HA. Our results reveal for the first time a role of TcVps15 as a key regulator of TcVps34 enzymatic activity and implicate the TcVps15-Vps34 complex in autophagy in T. cruzi, exposing a new key pathway to explore novel chemotherapeutic targets.
    MeSH term(s) Animals ; Autophagy ; Cadaverine/analogs & derivatives ; Cadaverine/metabolism ; Cell Culture Techniques ; Cell Membrane/metabolism ; Class III Phosphatidylinositol 3-Kinases/genetics ; Class III Phosphatidylinositol 3-Kinases/metabolism ; Class III Phosphatidylinositol 3-Kinases/physiology ; Cloning, Molecular ; DNA, Protozoan ; Enzyme Assays ; Gene Expression Regulation, Enzymologic ; Life Cycle Stages ; Mutagenesis, Site-Directed ; Phagosomes/metabolism ; Phosphatidylinositol 3-Kinases/genetics ; Phosphatidylinositol 3-Kinases/metabolism ; Phosphatidylinositol 3-Kinases/physiology ; Protozoan Proteins/biosynthesis ; Protozoan Proteins/genetics ; Protozoan Proteins/metabolism ; Sequence Analysis ; Transfection ; Trypanosoma cruzi/cytology ; Trypanosoma cruzi/enzymology ; Trypanosoma cruzi/genetics ; Trypanosoma cruzi/metabolism ; Two-Hybrid System Techniques ; Vacuolar Sorting Protein VPS15/genetics ; Vacuolar Sorting Protein VPS15/metabolism ; Vacuolar Sorting Protein VPS15/physiology ; Vacuoles/metabolism
    Chemical Substances DNA, Protozoan ; Protozoan Proteins ; Phosphatidylinositol 3-Kinases (EC 2.7.1.-) ; Class III Phosphatidylinositol 3-Kinases (EC 2.7.1.137) ; Vacuolar Sorting Protein VPS15 (EC 2.7.11.1) ; monodansylcadaverine (I9N81SC5HD) ; Cadaverine (L90BEN6OLL)
    Language English
    Publishing date 2017
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1147218-2
    ISSN 1550-7408 ; 1066-5234
    ISSN (online) 1550-7408
    ISSN 1066-5234
    DOI 10.1111/jeu.12367
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  6. Article: The Phosphatidylinositol 3‐kinase Class III Complex Containing TcVps15 and TcVps34 Participates in Autophagy in Trypanosoma cruzi

    Schoijet, Alejandra C / Tamara Sternlieb / Guillermo D. Alonso

    journal of eukaryotic microbiology. 2017 May, v. 64, no. 3

    2017  

    Abstract: Autophagy is a degradative process by which eukaryotic cells digest their own components to provide aminoacids that may function as energy source under nutritional stress conditions. There is experimental evidence for autophagy in parasitic protists ... ...

    Abstract Autophagy is a degradative process by which eukaryotic cells digest their own components to provide aminoacids that may function as energy source under nutritional stress conditions. There is experimental evidence for autophagy in parasitic protists belonging to the family Trypanosomatidae. However, few proteins implicated in this process have been characterized so far in these parasites. Moreover, it has been shown that autophagy is involved in Trypanosoma cruzi differentiation and thus might have a role in pathogenicity. Here, we report the cloning and biochemical characterization of TcVps15. In addition, we demonstrate that TcVps15 interact with the PI3K TcVps34 and that both proteins associate with cellular membranes. Under nutritional stress conditions, TcVps15 and TcVps34 modify their subcellular distribution showing a partial co‐localization in autophagosomes with TcAtg8.1 and using an active site TcVps15‐mutated version (TcVps15‐K219D‐HA) we demonstrated that this relocalization depends on the TcVps15 catalytic activity. Overexpression of TcVps15‐HA and TcVps15‐K219D‐HA also leads to increased accumulation of monodansylcadaverine (MDC) in autophagic vacuoles under nutritional stress conditions compared to wild‐type cells. In addition, the MDC‐specific activity shows to be significantly higher in TcVps15‐HA overexpressing cells when compared with TcVps15‐K219D‐HA. Our results reveal for the first time a role of TcVps15 as a key regulator of TcVps34 enzymatic activity and implicate the TcVps15‐Vps34 complex in autophagy in T. cruzi, exposing a new key pathway to explore novel chemotherapeutic targets.
    Keywords Trypanosoma cruzi ; active sites ; amino acids ; autophagy ; catalytic activity ; cell membranes ; drug therapy ; energy ; enzyme activity ; eukaryotic cells ; malnutrition ; parasites ; pathogenicity ; phosphatidylinositol 3-kinase ; proteins ; protists ; vacuoles
    Language English
    Dates of publication 2017-05
    Size p. 308-321.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 1147218-2
    ISSN 1550-7408 ; 1066-5234
    ISSN (online) 1550-7408
    ISSN 1066-5234
    DOI 10.1111/jeu.12367
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  7. Article ; Online: Homology Modeling and Molecular Dynamics Simulations of Trypanosoma cruzi Phosphodiesterase b1.

    Llanos, Manuel A / Alberca, Lucas N / Larrea, Salomé C Vilchez / Schoijet, Alejandra C / Alonso, Guillermo D / Bellera, Carolina L / Gavenet, Luciana / Talevi, Alan

    Chemistry & biodiversity

    2021  Volume 19, Issue 1, Page(s) e202100712

    Abstract: Cyclic nucleotide phosphodiesterases have been implicated in the proliferation, differentiation and osmotic regulation of trypanosomatids; in some trypanosomatid species, they have been validated as molecular targets for the development of new ... ...

    Abstract Cyclic nucleotide phosphodiesterases have been implicated in the proliferation, differentiation and osmotic regulation of trypanosomatids; in some trypanosomatid species, they have been validated as molecular targets for the development of new therapeutic agents. Because the experimental structure of Trypanosoma cruzi PDEb1 (TcrPDEb1) has not been solved so far, an homology model of the target was created using the structure of Trypanosoma brucei PDEb1 (TbrPDEb1) as a template. The model was refined by extensive enhanced sampling molecular dynamics simulations, and representative snapshots were extracted from the trajectory by combined clustering analysis. This structural ensemble was used to develop a structure-based docking model of the target. The docking accuracy of the model was validated by redocking and cross-docking experiments using all available crystal structures of TbrPDEb1, whereas the scoring accuracy was validated through a retrospective screen, using a carefully curated dataset of compounds assayed against TbrPDEb1 and/or TcrPDEb1. Considering the results from in silico validations, the model may be applied in prospective virtual screening campaigns to identify novel hits, as well as to guide the rational design of potent and selective inhibitors targeting this enzyme.
    MeSH term(s) 3',5'-Cyclic-AMP Phosphodiesterases/chemistry ; 3',5'-Cyclic-AMP Phosphodiesterases/metabolism ; Amino Acid Sequence ; Area Under Curve ; Binding Sites ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Protein Structure, Tertiary ; Protozoan Proteins/chemistry ; Protozoan Proteins/metabolism ; ROC Curve ; Sequence Alignment ; Small Molecule Libraries/chemistry ; Small Molecule Libraries/metabolism ; Trypanosoma brucei brucei/enzymology ; Trypanosoma cruzi/enzymology
    Chemical Substances Protozoan Proteins ; Small Molecule Libraries ; 3',5'-Cyclic-AMP Phosphodiesterases (EC 3.1.4.17) ; PDEB1 protein, Trypanosoma brucei (EC 3.1.4.17)
    Language English
    Publishing date 2021-12-16
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2139001-0
    ISSN 1612-1880 ; 1612-1872
    ISSN (online) 1612-1880
    ISSN 1612-1872
    DOI 10.1002/cbdv.202100712
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  8. Article ; Online: TbVps15 is required for vesicular transport and cytokinesis in Trypanosoma brucei.

    Schoijet, Alejandra C / Miranda, Kildare / Sternlieb, Tamara / Barrera, Nadia M / Girard-Dias, Wendell / de Souza, Wanderley / Alonso, Guillermo D

    Molecular and biochemical parasitology

    2017  Volume 219, Page(s) 33–41

    Abstract: The class III phosphatidylinositol 3-kinase (PI3K) Vps34 is an important regulator of key cellular functions, including cell growth, survival, intracellular trafficking, autophagy and nutrient sensing. In yeast, Vps34 is associated with the putative ... ...

    Abstract The class III phosphatidylinositol 3-kinase (PI3K) Vps34 is an important regulator of key cellular functions, including cell growth, survival, intracellular trafficking, autophagy and nutrient sensing. In yeast, Vps34 is associated with the putative serine/threonine protein kinase Vps15, however, its role in signaling has not been deeply evaluated. Here, we have identified the Vps15 orthologue in Trypanosoma brucei, named TbVps15. Knockdown of TbVps15 expression by interference RNA resulted in inhibition of cell growth and blockage of cytokinesis. Scanning electron microcopy revealed a variety of morphological abnormalities, with enlarged parasites and dividing cells that often exhibited a detached flagellum. Transmission electron microscopy analysis of TbVps15 RNAi cells showed an increase in intracellular vacuoles of the endomembrane system and some cells displayed an enlargement of the flagellar pocket, a common feature of cells defective in endocytosis. Moreover, uptake of dextran, transferrin and Concanavalin A was impaired. Finally, TbVps15 downregulation affected the PI3K activity, supporting the hypothesis that TbVps15 and TbVps34 form a complex as occurs in other organisms. In summary, we propose that TbVps15 has a role in the maintenance of cytokinesis, endocytosis and intracellular trafficking in T. brucei.
    MeSH term(s) Class III Phosphatidylinositol 3-Kinases/metabolism ; Cytokinesis ; Disease Transmission, Infectious ; Endocytosis ; Gene Knockdown Techniques ; Microscopy, Atomic Force ; Microscopy, Electron, Transmission ; Phosphatidylinositol 3-Kinase/analysis ; Protein Binding ; Trypanosoma brucei brucei/cytology ; Trypanosoma brucei brucei/enzymology ; Trypanosoma brucei brucei/genetics ; Trypanosoma brucei brucei/physiology ; Vacuolar Sorting Protein VPS15/genetics ; Vacuolar Sorting Protein VPS15/metabolism
    Chemical Substances Class III Phosphatidylinositol 3-Kinases (EC 2.7.1.137) ; Phosphatidylinositol 3-Kinase (EC 2.7.1.137) ; Vacuolar Sorting Protein VPS15 (EC 2.7.11.1)
    Language English
    Publishing date 2017-11-16
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 756166-0
    ISSN 1872-9428 ; 0166-6851
    ISSN (online) 1872-9428
    ISSN 0166-6851
    DOI 10.1016/j.molbiopara.2017.11.004
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  9. Article: TbVps15 is required for vesicular transport and cytokinesis in Trypanosoma brucei

    Schoijet, Alejandra C / Kildare Miranda / Tamara Sternlieb / Nadia M. Barrera / Wendell Girard-Dias / Wanderley de Souza / Guillermo D. Alonso

    Molecular and biochemical parasitology. 2017,

    2017  

    Abstract: The class III phosphatidylinositol 3-kinase (PI3K) Vps34 is an important regulator of key cellular functions, including cell growth, survival, intracellular trafficking, autophagy and nutrient sensing. In yeast, Vps34 is associated with the putative ... ...

    Abstract The class III phosphatidylinositol 3-kinase (PI3K) Vps34 is an important regulator of key cellular functions, including cell growth, survival, intracellular trafficking, autophagy and nutrient sensing. In yeast, Vps34 is associated with the putative serine/threonine protein kinase Vps15, however, its role in signaling has not been deeply evaluated. Here, we have identified the Vps15 orthologue in Trypanosoma brucei, named TbVps15. Knockdown of TbVps15 expression by interference RNA resulted in inhibition of cell growth and blockage of cytokinesis. Scanning electron microcopy revealed a variety of morphological abnormalities, with enlarged parasites and dividing cells that often exhibited a detached flagellum. Transmission electron microscopy analysis of TbVps15 RNAi cells showed an increase in intracellular vacuoles of the endomembrane system and some cells displayed an enlargement of the flagellar pocket, a common feature of cells defective in endocytosis. Moreover, uptake of dextran, transferrin and Concanavalin A was impaired. Finally, TbVps15 downregulation affected the PI3K activity, supporting the hypothesis that TbVps15 and TbVps34 form a complex as occurs in other organisms. In summary, we propose that TbVps15 has a role in the maintenance of cytokinesis, endocytosis and intracellular trafficking in T. brucei.
    Keywords RNA interference ; Trypanosoma brucei ; autophagy ; cell growth ; concanavalin A ; cytokinesis ; dextran ; endomembrane system ; flagellum ; parasites ; phosphatidylinositol 3-kinase ; physiological transport ; protein-serine-threonine kinases ; threonine ; transferrin ; transmission electron microscopy ; vacuoles ; yeasts
    Language English
    Size p. .
    Publishing place Elsevier B.V.
    Document type Article
    Note Pre-press version
    ZDB-ID 756166-0
    ISSN 1872-9428 ; 0166-6851
    ISSN (online) 1872-9428
    ISSN 0166-6851
    DOI 10.1016/j.molbiopara.2017.11.004
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  10. Article ; Online: Venom alkaloids against Chagas disease parasite: search for effective therapies.

    Silva, Rafael C M Costa / Fox, Eduardo G P / Gomes, Fabio M / Feijó, Daniel F / Ramos, Isabela / Koeller, Carolina M / Costa, Tatiana F R / Rodrigues, Nathalia S / Lima, Ana P / Atella, Georgia C / Miranda, Kildare / Schoijet, Alejandra C / Alonso, Guillermo D / de Alcântara Machado, Ednildo / Heise, Norton

    Scientific reports

    2020  Volume 10, Issue 1, Page(s) 10642

    Abstract: Chagas disease is an important disease affecting millions of patients in the New World and is caused by a protozoan transmitted by haematophagous kissing bugs. It can be treated with drugs during the early acute phase; however, effective therapy against ... ...

    Abstract Chagas disease is an important disease affecting millions of patients in the New World and is caused by a protozoan transmitted by haematophagous kissing bugs. It can be treated with drugs during the early acute phase; however, effective therapy against the chronic form of Chagas disease has yet to be discovered and developed. We herein tested the activity of solenopsin alkaloids extracted from two species of fire ants against the protozoan parasite Trypanosoma cruzi, the aetiologic agent of Chagas disease. Although IC
    MeSH term(s) Alkaloids/toxicity ; Animals ; Ants/chemistry ; Apoptosis ; Arthropod Venoms/toxicity ; Autophagy ; CHO Cells ; Cricetinae ; Cricetulus ; Macaca mulatta ; Macrophages/parasitology ; Osmotic Pressure ; Trypanocidal Agents/toxicity ; Trypanosoma cruzi/drug effects ; Trypanosoma cruzi/metabolism ; Trypanosoma cruzi/pathogenicity
    Chemical Substances Alkaloids ; Arthropod Venoms ; Trypanocidal Agents
    Language English
    Publishing date 2020-06-30
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-020-67324-8
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