24 results on '"Moretti, Nilmar Silvio"'
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2. Panacea within a Pandora's box: the antiparasitic effects of phospholipases A2 (PLA2s) from snake venoms
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Teixeira, Samuel Cota, da Silva, Marcelo Santos, Gomes, Antoniel Augusto Severo, Moretti, Nilmar Silvio, Lopes, Daiana Silva, Ferro, Eloisa Amália Vieira, and Rodrigues, Veridiana de Melo
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- 2022
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3. Alteration in Ikaros expression promotes B-1 cell differentiation into phagocytes
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Oliveira, Vivian Cristina de, Sodré, Ana Clara Pires, Gomes, Caio Perez, Moretti, Nilmar Silvio, Pesquero, João Bosco, and Popi, Ana Flavia
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- 2018
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4. Chemogenetic Characterization of Inositol Phosphate Metabolic Pathway Reveals Druggable Enzymes for Targeting Kinetoplastid Parasites
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Cestari, Igor, Haas, Paige, Moretti, Nilmar Silvio, Schenkman, Sergio, and Stuart, Ken
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- 2016
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5. Trypanosoma cruzi
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Moretti, Nilmar Silvio, Mortara, Renato Arruda, and Schenkman, Sergio
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- 2020
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6. An Epidemiological Survey of Malaria Infection in Espírito Santo State, Brazil, from 2007 to 2017.
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Oliveira, Nayna Carvalho, Boscalha, Lais Rosa, Toledo, Cinthia Emerich, Pezzin, Felipe Sarlo, Cisari, Bruno Costanza, Maran, Suellen Rodrigues, Diniz, Laís Rodrigues, Freitas, Pedro Henrique Schultz Corcino, Cruzeiro, Adenilton, Eutropio, Frederico, Garbin, Juliana Rodrigues Tovar, Segatto, Marcela, Moretti, Nilmar Silvio, and Nunes, Vinícius Santana
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MALARIA ,NEGLECTED diseases ,CITIES & towns ,MEDICAL care ,INFECTION - Abstract
Malaria is one of the most important neglected diseases in the world, and Brazil has the largest number of cases on the American continent. In Brazil, this disease is considered to be endemic in the Amazon region, although malaria lethality in extra-Amazonian regions is higher. Recently, it has been shown that malaria cases of autochthonous origin are not uncommon in the southeastern states. Among these states, Espírito Santo (ES) has the highest percentage of reported cases. This study aimed to describe the epidemiological profile and main factors that contribute to the incidence of malaria cases in this region, which corresponded to 4155 notifications in the 2007–2017 period based on data obtained from the Special Center for Epidemiological Surveillance of Espírito Santo. The most affected group was males aged around 40 years old, and most of the cases registered were of autochthonous origin. The number of malaria cases decreased during the period 2007–2017. Among the causative species, P. vivax was predominant, and it was followed by P. falciparum as the second most common species of all malaria cases. The main cities of ES presented high records of malaria disease, with high numbers of malaria cases in Santa Tereza, Domingos Martins, Alfredo Chaves, Santa Leopoldina, and Marechal Floriano. It is up to the local governments to advise the population about the epidemiological situation and to standardize medical care for individuals with suspected malaria. [ABSTRACT FROM AUTHOR]
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- 2023
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7. Catalase expression impairs oxidative stress-mediated signalling in Trypanosoma cruzi
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FREIRE, ANNA CLÁUDIA GUIMARÃES, ALVES, CERES LUCIANA, GOES, GRAZIELLE RIBEIRO, RESENDE, BRUNO CARVALHO, MORETTI, NILMAR SILVIO, NUNES, VINÍCIUS SANTANA, AGUIAR, PEDRO HENRIQUE NASCIMENTO, TAHARA, ERICH BIRELLI, FRANCO, GLÓRIA REGINA, MACEDO, ANDRÉA MARA, PENA, SÉRGIO DANILO JUNHO, GADELHA, FERNANDA RAMOS, GUARNERI, ALESSANDRA APARECIDA, SCHENKMAN, SERGIO, VIEIRA, LEDA QUERCIA, and MACHADO, CARLOS RENATO
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- 2017
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8. Mitochondrial Sirtuin TcSir2rp3 Affects TcSODA Activity and Oxidative Stress Response in Trypanosoma cruzi.
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dos Santos Moura, Leila, Santana Nunes, Vinícius, Gomes, Antoniel A. S., Sousa, Ana Caroline de Castro Nascimento, Fontes, Marcos R. M., Schenkman, Sergio, and Moretti, Nilmar Silvio
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OXIDATIVE stress ,TRYPANOSOMA cruzi ,MOLECULAR dynamics ,ACETYLATION ,SUPEROXIDE dismutase ,POST-translational modification - Abstract
Trypanosoma cruzi faces a variety of environmental scenarios during its life cycle, which include changes in the redox environment that requires a fine regulation of a complex antioxidant arsenal of enzymes. Reversible posttranslational modifications, as lysine acetylation, are a fast and economical way for cells to react to environmental conditions. Recently, we found that the main antioxidant enzymes, including the mitochondrial superoxide dismutase A (TcSODA) are acetylated in T. cruzi , suggesting that protein acetylation could participate in the oxidative stress response in T. cruzi. Therefore, we investigated whether mitochondrial lysine deacetylase TcSir2rp3 was involved in the activity control of TcSODA. We observed an increased resistance to hydrogen peroxide and menadione in parasites overexpressing TcSir2rp3. Increased resistance was also found for benznidazole and nifurtimox, known to induce reactive oxidative and nitrosactive species in the parasite, associated to that a reduction in the ROS levels was observed. To better understand the way TcSir2rp3 could contributes to oxidative stress response, we analyzed the expression of TcSODA in the TcSir2rp3 overexpressing parasites and did not detect any increase in protein levels of this enzyme. However, we found that these parasites presented higher levels of superoxide dismutase activity, and also that TcSir2rp3 and TcSODA interacts in vivo. Knowing that TcSODA is acetylated at lysine residues K44 and K97, and that K97 is located at a similar region in the protein structure as K68 in human manganese superoxide dismutase (MnSOD), responsible for regulating MnSOD activity, we generated mutated versions of TcSODA at K44 and K97 and found that replacing K97 by glutamine, which mimics an acetylated lysine, negatively affects the enzyme activity in vitro. By using molecular dynamics approaches, we revealed that acetylation of K97 induces specific conformational changes in TcSODA with respect to hydrogen-bonding pattern to neighbor residues, suggesting a key participation of this residue to modulate the affinity to O 2 − . Taken together, our results showed for the first time the involvement of lysine acetylation in the maintenance of homeostatic redox state in trypanosomatids, contributing to the understanding of mechanisms used by T. cruzi to progress during the infection. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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9. Cyclophilin 19 secreted in the host cell cytosol by Trypanosoma cruzi promotes ROS production required for parasite growth.
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Santos, Gregory Pedroso, Abukawa, Fernanda Midori, Souza‐Melo, Normanda, Alcântara, Laura Maria, Bittencourt‐Cunha, Paula, Moraes, Carolina Borsoi, Jha, Bijay Kumar, McGwire, Bradford S., Moretti, Nilmar Silvio, and Schenkman, Sergio
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CHAGAS' disease ,CYCLOPHILINS ,TRYPANOSOMA cruzi ,CYTOSOL ,CYCLOSPORINE ,NADPH oxidase - Abstract
Infection by Trypanosoma cruzi, the protozoan parasite that causes Chagas disease, depends on reactive oxygen species (ROS), which has been described to induce parasite proliferation in mammalian host cells. It is unknown how the parasite manages to increase host ROS levels. Here, we found that intracellular T. cruzi forms release in the host cytosol its major cyclophilin of 19 kDa (TcCyp19). Parasites depleted of TcCyp19 by using CRISPR/Cas9 gene replacement proliferate inefficiently and fail to increase ROS, compared to wild type parasites or parasites with restored TcCyp19 gene expression. Expression of TcCyp19 in L6 rat myoblast increased ROS levels and restored the proliferation of TcCyp19 depleted parasites. These events could also be inhibited by cyclosporin A, (a cyclophilin inhibitor), and by polyethylene glycol‐linked to antioxidant enzymes. TcCyp19 was found more concentrated in the membrane leading edges of the host cells in regions that also accumulate phosphorylated p47phox, as observed to the endogenous cyclophilin A, suggesting some mechanisms involved with the translocation process of the regulatory subunit p47phox in the activation of the NADPH oxidase enzymatic complex. We concluded that cyclophilin released in the host cell cytosol by T. cruzi mediates the increase of ROS, required to boost parasite proliferation in mammalian hosts. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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10. Deregulation of Ikaros expression in B‐1 cells: New insights in the malignant transformation to chronic lymphocytic leukemia.
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Oliveira, Vivian Cristina de, Lacerda, Marcelo Pitombeira de, Moraes, Bárbara Bomfim Muniz, Gomes, Caio Perez, Maricato, Juliana Terzi, Souza, Olivia Fonseca, Schenkman, Sergio, Pesquero, João Bosco, Moretti, Nilmar Silvio, Rodrigues, Celso Arrais, and Popi, Ana Flavia
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CHRONIC lymphocytic leukemia ,FLUDARABINE ,TALL-1 (Protein) ,CHRONIC leukemia ,LYMPHOPROLIFERATIVE disorders ,B cells ,GENETIC regulation - Abstract
Chronic lymphocytic leukemia (CLL) is a chronic form of leukemia that originates from an abnormal expansion of CD5+B‐1 cells. Deregulation in the BCR signaling is associated with B‐cell transformation. Contrariwise to B‐2 cells, BCR engagement in B‐1 cells results in low proliferation rate and increased apoptosis population, whereas overactivation may be associated with lymphoproliferative disorders. It has been demonstrated that several transcription factors that are involved in the B cell development play a role in the regulation of BCR function. Among them, Ikaros is considered an essential regulator of lymphoid differentiation and activation. Several reports suggest that Ikaros expression is deregulated in different forms of leukemia. Herein, we demonstrated that CLL cells show decreased Ikaros expression and abnormal cytoplasmic cell localization. These alterations were also observed in radioresistant B‐1 cells, which present high proliferative activity, suggesting that abnormal localization of Ikaros could determine its loss of function. Furthermore, Ikaros knockdown increased the expression of BCR pathway components in murine B‐1 cells, such as Lyn, Blnk, and CD19. Additionally, in the absence of Ikaros, B‐1 cells become responsive to BCR stimulus, increasing cell proliferation even in the absence of antigen stimulation. These results suggested that Ikaros is an important controller of B‐1 cell proliferation by interfering with the BCR activity. Therefore, altered Ikaros expression in CLL or radioresistant B‐1 cells could determine a responsive status of BCR to self‐antigens, which would culminate in the clonal expansion of B‐1 cells. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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11. Comparative Proteomic Analysis of Lysine Acetylation in Trypanosomes.
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Moretti, Nilmar Silvio, Cestari, Igor, Anupama, Atashi, Stuart, Ken, and Schenkman, Sergio
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- 2018
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12. Nuclear subcompartments: an overview.
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Nunes, Vinícius Santana and Moretti, Nilmar Silvio
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NUCLEOPLASM , *COILED bodies (Cytology) , *NUCLEOLUS , *SPINAL muscular atrophy , *DISEASES - Abstract
The advance in biochemical and microscopy techniques has revealed the complexity and intricate nucleoplasm structure. Several subcompartments were identified in nucleus and the importance of these subcompartments in processes crucial for normal nuclear activity has been demonstrated. In this mini-review, we will give an overview about the composition, function, and importance of the major nuclear subcompartments. Also, we will show the impact that perturbing these structures can cause in normal nuclear activity, and how these can contribute to the development of some human diseases. [ABSTRACT FROM AUTHOR]
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- 2017
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13. Toxoplasma gondii Chitinase Induces Macrophage Activation.
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Almeida, Fausto, Sardinha-Silva, Aline, da Silva, Thiago Aparecido, Pessoni, André Moreira, Pinzan, Camila Figueiredo, Alegre-Maller, Ana Claudia Paiva, Cecílio, Nerry Tatiana, Moretti, Nilmar Silvio, Damásio, André Ricardo Lima, Pedersoli, Wellington Ramos, Mineo, José Roberto, Silva, Roberto Nascimento, and Roque-Barreira, Maria Cristina
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TOXOPLASMA gondii ,MACROPHAGE activation ,CHITINASE ,CYTOPLASM ,PH effect - Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite found worldwide that is able to chronically infect almost all vertebrate species, especially birds and mammalians. Chitinases are essential to various biological processes, and some pathogens rely on chitinases for successful parasitization. Here, we purified and characterized a chitinase from T. gondii. The enzyme, provisionally named Tg_chitinase, has a molecular mass of 13.7 kDa and exhibits a Km of 0.34 mM and a Vmax of 2.64. The optimal environmental conditions for enzymatic function were at pH 4.0 and 50°C. Tg_chitinase was immunolocalized in the cytoplasm of highly virulent T. gondii RH strain tachyzoites, mainly at the apical extremity. Tg_chitinase induced macrophage activation as manifested by the production of high levels of pro-inflammatory cytokines, a pathogenic hallmark of T. gondii infection. In conclusion, to our knowledge, we describe for the first time a chitinase of T. gondii tachyzoites and provide evidence that this enzyme might influence the pathogenesis of T. gondii infection. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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14. Iron superoxide dismutases in eukaryotic pathogens: new insights from Apicomplexa and Trypanosoma structures.
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Phan, Isabelle Q. H., Davies, Douglas R., Moretti, Nilmar Silvio, Shanmugam, Dhanasekaran, Cestari, Igor, Anupama, Atashi, Fairman, James W., Edwards, Thomas E., Stuart, Kenneth, Schenkman, Sergio, and Myler, Peter J.
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EUKARYOTIC cells ,IRON ,SUPEROXIDE dismutase ,TRYPANOSOMA ,APICOMPLEXA ,STRUCTURAL genomics - Abstract
Prior studies have highlighted the potential of superoxide dismutases as drug targets in eukaryotic pathogens. This report presents the structures of three iron-dependent superoxide dismutases (FeSODs) from Trypanosoma cruzi, Leishmania major and Babesia bovis. Comparison with existing structures from Plasmodium and other trypanosome isoforms shows a very conserved overall fold with subtle differences. In particular, structural data suggest that B. bovis FeSOD may display similar resistance to peroxynitrite-mediated inactivation via an intramolecular electron-transfer pathway as previously described in T. cruzi FeSOD isoform B, thus providing valuable information for structure-based drug design. Furthermore, lysine-acetylation results in T. cruzi indicate that acetylation occurs at a position close to that responsible for the regulation of acetylation-mediated activity in the human enzyme. [ABSTRACT FROM AUTHOR]
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- 2015
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15. A Membrane-bound eIF2 Alpha Kinase Located in Endosomes Is Regulated by Heme and Controls Differentiation and ROS Levels in Trypanosoma cruzi.
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da Silva Augusto, Leonardo, Moretti, Nilmar Silvio, Ramos, Thiago Cesar Prata, de Jesus, Teresa Cristina Leandro, Zhang, Min, Castilho, Beatriz A., and Schenkman, Sergio
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KINASES , *ENDOSOMES , *TRYPANOSOMA cruzi , *PHOSPHORYLATION , *PROTEIN kinases - Abstract
Translation initiation has been described as a key step for the control of growth and differentiation of several protozoan parasites in response to environmental changes. This occurs by the activation of protein kinases that phosphorylate the alpha subunit of the translation initiation factor 2 (eIF2α), which decreases translation, and in higher eukaryotes favors the expression of stress remedial response genes. However, very little is known about the signals that activate eIF2α kinases in protozoan parasites. Here, we characterized an eIF2α kinase of Trypanosoma cruzi (TcK2), the agent of Chagas’ disease, as a transmembrane protein located in organelles that accumulate nutrients in proliferating parasite forms. We found that heme binds specifically to the catalytic domain of the kinase, inhibiting its activity. In the absence of heme, TcK2 is activated, arresting cell growth and inducing differentiation of proliferative into infective and non-proliferative forms. Parasites lacking TcK2 lose this differentiation capacity and heme is not stored in reserve organelles, remaining in the cytosol. TcK2 null cells display growth deficiencies, accumulating hydrogen peroxide that drives the generation of reactive oxygen species. The augmented level of hydrogen peroxide occurs as a consequence of increased superoxide dismutase activity and decreased peroxide activity. These phenotypes could be reverted by the re-expression of the wild type but not of a TcK2 dead mutant. These findings indicate that heme is a key factor for the growth control and differentiation through regulation of an unusual type of eIF2α kinase in T. cruzi. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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16. Chromatin modifications in trypanosomes due to stress.
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Moretti, Nilmar Silvio and Schenkman, Sergio
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CHROMATIN , *TRYPANOSOMATIDAE , *VETERINARY health risk assessment , *DNA repair , *GENE expression , *GENETIC transcription , *PARASITES - Abstract
Trypanosomatids are parasites of worldwide distribution with relevant importance in human and veterinary health, which inhabit invertebrate and vertebrate hosts, such that they are exposed to large environmental variations during their life cycle. The signalling mechanisms and molecular basis that lead these parasites to adjust to such distinct conditions are beginning to be understood, and are somehow related to modifications in gene expression. Although the control of gene expression in this group of organisms happens predominantly at the post-transcriptional level, they present modifications in chromatin that has been implicated in transcription initiation, replication and DNA repair. Here, we explore the current scenario of chromatin alterations in these protozoans and how these changes affect transcription, replication and DNA repair in response to environmental modifications. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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17. Trimethylation of histone H3K76 by Dot1B enhances cell cycle progression after mitosis in Trypanosoma cruzi.
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Nunes, Vinicius Santana, Moretti, Nilmar Silvio, da Silva, Marcelo Santos, Elias, Maria Carolina, Janzen, Christian J., and Schenkman, Sergio
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CELL cycle , *TRYPANOSOMA cruzi , *HISTONE methyltransferases , *CELL growth , *MITOSIS , *PARASITIC diseases , *METHYLTRANSFERASES , *HISTONES - Abstract
Dot1 enzymes are histone methyltransferases that mono-, di- and trimethylate lysine 79 of histone H3 to affect several nuclear processes. The functions of these different methylation states are still largely unknown. Trypanosomes, which are flagellated protozoa that cause several parasitic diseases, have two Dot1 homologues. Dot1A catalyzes the mono- and dimethylation of lysine 76 during late G2 and mitosis, and Dot1B catalyzes trimethylation, which is a modification found in all stages of the cell cycle. Here, we generated Trypanosoma cruzi lines lacking Dot1B. Deletion of one allele resulted in parasites with increased levels of mono- and dimethylation and a reduction in H3K76me3. In the full knockout (DKO), no trimethylation was observed. Both the DKO and the single knockout (SKO) showed aberrant morphology and decreased growth due to cell cycle arrest after G2. This phenotype could be rescued by caffeine in the DKO, as caffeine is a checkpoint inhibitor of the cell cycle. The knockouts also phosphorylated γH2A without producing extensive DNA breaks, and Dot1B-depleted cells were more susceptible to general checkpoint kinase inhibitors, suggesting that a lack of H3K76 trimethylation prevents the initiation and/or completion of cytokinesis. Unlabelled Image • T. cruzi contains two Dot1 enzymes (Dot1A and B) that mono-, di- and trimethylate lysine 76 of histone H3, acting in mitosis. • Trimethylation is reduced and dimethylation predominates after depleting Dot1B in T. cruzi , delaying the exit of mitosis. • KO cells present high level of H2A-phosphorylated histone through activation of checkpoint kinases that affect cytokinesis. • Covering the dimethylation of the histone H3 is important to complete the cell cycle after mitosis. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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18. Expression of non-acetylatable lysines 10 and 14 of histone H4 impairs transcription and replication in Trypanosoma cruzi.
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Ramos, Thiago Cesar Prata, Nunes, Vinicius Santana, Nardelli, Sheila Cristina, dos Santos Pascoalino, Bruno, Moretti, Nilmar Silvio, Rocha, Antonio Augusto, da Silva Augusto, Leonardo, and Schenkman, Sergio
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HISTONES , *GENE expression , *TRYPANOSOMA cruzi , *GENETIC transcription , *DNA replication , *POST-translational modification , *MOLECULAR chaperones - Abstract
The histone H4 from Trypanosomatids diverged from other eukaryotes in the N-terminus, a region that undergoes post-translation modifications involved in the control of gene expression, DNA replication, and chromatin assembly. Nonetheless, the N-terminus of Trypanosoma cruzi histone H4 is mainly acetylated at lysine 4. The lysines 10 and 14 are also acetylated, although at less extent, increasing during the S-phase or after DNA damage, which suggests a regulatory function. Here, we investigated the roles of these acetylations by expressing non-acetylated forms of histone H4 in T. cruzi. We found that histone H4 containing arginines at positions 10 or 14, to prevent acetylation were transported to the nucleus and inserted into the chromatin. However, their presence, even at low levels, interfered with DNA replication and transcription, causing a significant growth arrest of the cells. The absence of acetylation also increased the amount of soluble endogenous histones H3 and H4 and affected the interaction with Asf1, a histone chaperone. Therefore, acetylation of lysines 10 and 14 of the histone H4 in trypanosomes could be required for chromatin assembly and/or remodeling required for transcription and replication. [ABSTRACT FROM AUTHOR]
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- 2015
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19. Antileishmanial metallodrugs and the elucidation of new drug targets linked to post-translational modifications machinery: pitfalls and progress.
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Monte Neto RLD, Moreira POL, de Sousa AM, Garcia MADN, Maran SR, and Moretti NS
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- Drug Discovery, Humans, Protein Processing, Post-Translational, Antiprotozoal Agents chemistry, Leishmania, Leishmaniasis drug therapy
- Abstract
Despite the increasing number of manuscripts describing potential alternative antileishmanial compounds, little is advancing on translating these knowledges to new products to treat leishmaniasis. This is in part due to the lack of standardisations during pre-clinical drug discovery stage and also depends on the alignment of goals among universities/research centers, government and pharmaceutical industry. Inspired or not by drug repurposing, metal-based antileishmanial drugs represent a class that deserves more attention on its use for leishmaniasis chemotherapy. Together with new chemical entities, progresses have been made on the knowledge of parasite-specific drug targets specially after using CRISPR/Cas system for functional studies. In this regard, Leishmania parasites undergoe post-translational modification as key regulators in several cellular processes, which represents an entire new field for drug target elucidation, once this is poorly explored. This perspective review describes the advances on antileishmanial metallodrugs and the elucidation of drug targets based on post-translational modifications, highlighting the limitations on the drug discovery/development process and suggesting standardisations focused on products addressed to who need it most.
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- 2022
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20. Cyclophilin 19 secreted in the host cell cytosol by Trypanosoma cruzi promotes ROS production required for parasite growth.
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Dos Santos GP, Abukawa FM, Souza-Melo N, Alcântara LM, Bittencourt-Cunha P, Moraes CB, Jha BK, McGwire BS, Moretti NS, and Schenkman S
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- Animals, Cyclophilins biosynthesis, Cyclophilins genetics, Cytosol chemistry, Myoblasts parasitology, Protozoan Proteins genetics, Protozoan Proteins metabolism, Rats, Trypanosoma cruzi genetics, Cyclophilins metabolism, Cytosol metabolism, Host-Parasite Interactions, Reactive Oxygen Species metabolism, Trypanosoma cruzi growth & development, Trypanosoma cruzi metabolism
- Abstract
Infection by Trypanosoma cruzi, the protozoan parasite that causes Chagas disease, depends on reactive oxygen species (ROS), which has been described to induce parasite proliferation in mammalian host cells. It is unknown how the parasite manages to increase host ROS levels. Here, we found that intracellular T. cruzi forms release in the host cytosol its major cyclophilin of 19 kDa (TcCyp19). Parasites depleted of TcCyp19 by using CRISPR/Cas9 gene replacement proliferate inefficiently and fail to increase ROS, compared to wild type parasites or parasites with restored TcCyp19 gene expression. Expression of TcCyp19 in L6 rat myoblast increased ROS levels and restored the proliferation of TcCyp19 depleted parasites. These events could also be inhibited by cyclosporin A, (a cyclophilin inhibitor), and by polyethylene glycol-linked to antioxidant enzymes. TcCyp19 was found more concentrated in the membrane leading edges of the host cells in regions that also accumulate phosphorylated p47
phox , as observed to the endogenous cyclophilin A, suggesting some mechanisms involved with the translocation process of the regulatory subunit p47phox in the activation of the NADPH oxidase enzymatic complex. We concluded that cyclophilin released in the host cell cytosol by T. cruzi mediates the increase of ROS, required to boost parasite proliferation in mammalian hosts., (© 2020 John Wiley & Sons Ltd.)- Published
- 2021
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21. Extracellular Vesicles From Sporothrix brasiliensis Are an Important Virulence Factor That Induce an Increase in Fungal Burden in Experimental Sporotrichosis.
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Ikeda MAK, de Almeida JRF, Jannuzzi GP, Cronemberger-Andrade A, Torrecilhas ACT, Moretti NS, da Cunha JPC, de Almeida SR, and Ferreira KS
- Abstract
Sporotrichosis is a mycosis that affects the skin, lymphatic system and other organs in humans and animals. The disease has a worldwide distribution, with endemic areas in Brazil, and is caused by a complex of species, including Sporothrix brasiliensis . Some fungi release extracellular vesicles (EVs) that can interact with the host cell and modulate the host immune response. The aim of this study was to analyze the participation of S. brasiliensis EVs in the modulation of dendritic cells (DCs) and in the control of infection in vivo . Our results showed that in vitro , the EVs isolated from S. brasiliensis induced an increase in the phagocytic index and fungal burden in DCs. In addition, we observed a significant increase in IL-12p40 and TNF-α cytokine production. Then, the EVs were inoculated into BALB/c mice before subcutaneous infection with yeast, and the lesion was analyzed after 21, 35, and 42 days. An increase in fungal burden and lesion diameter were observed after 21 days in mice inoculated with a high concentration of EVs. However, after 35 days, we observed a regression of the lesion, which persisted until 42 days after infection. Interestingly, we observed an increase in fungal burden in these mice. In addition, we observed the presence of immunogenic components and proteins that could be related with virulence in EVs. These results suggest that EVs can play an important role in virulence and modulation of the host immune system during experimental S. brasiliensis infection.
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- 2018
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22. Chromatin Proteomics Reveals Variable Histone Modifications during the Life Cycle of Trypanosoma cruzi.
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de Jesus TC, Nunes VS, Lopes Mde C, Martil DE, Iwai LK, Moretti NS, Machado FC, de Lima-Stein ML, Thiemann OH, Elias MC, Janzen C, Schenkman S, and da Cunha JP
- Subjects
- Acetylation, Cell Cycle, Gene Expression Regulation, Methylation, Phosphorylation, Protein Processing, Post-Translational physiology, Trypanosoma cruzi, Chromatin chemistry, Histone Code, Life Cycle Stages, Proteomics methods
- Abstract
Histones are well-conserved proteins that form the basic structure of chromatin in eukaryotes and undergo several post-translational modifications, which are important for the control of transcription, replication, DNA damage repair, and chromosome condensation. In early branched organisms, histones are less conserved and appear to contain alternative sites for modifications, which could reveal evolutionary unique functions of histone modifications in gene expression and other chromatin-based processes. Here, by using high-resolution mass spectrometry, we identified and quantified histone post-translational modifications in two life cycle stages of Trypanosoma cruzi, the protozoan parasite that causes Chagas disease. We detected 44 new modifications, namely: 18 acetylations, seven monomethylations, seven dimethylations, seven trimethylations, and four phosphorylations. We found that replicative (epimastigote stage) contains more histone modifications than nonreplicative and infective parasites (trypomastigote stage). Acetylations of lysines at the C-terminus of histone H2A and methylations of lysine 23 of histone H3 were found to be enriched in trypomastigotes. In contrast, phosphorylation in serine 23 of H2B and methylations of lysine 76 of histone H3 predominates in proliferative states. The presence of one or two methylations in the lysine 76 was found in cells undergoing mitosis and cytokinesis, typical of proliferating parasites. Our findings provide new insights into the role of histone modifications related to the control of gene expression and cell-cycle regulation in an early divergent organism.
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- 2016
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23. Characterization of Trypanosoma cruzi Sirtuins as Possible Drug Targets for Chagas Disease.
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Moretti NS, da Silva Augusto L, Clemente TM, Antunes RP, Yoshida N, Torrecilhas AC, Cano MI, and Schenkman S
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- Acetylation drug effects, Animals, Cell Line, Cell Survival drug effects, DNA Repair drug effects, Macaca mulatta, Chagas Disease drug therapy, Naphthols pharmacology, Phenylpropionates pharmacology, Sirtuins drug effects, Trypanosoma cruzi drug effects
- Abstract
Acetylation of lysine is a major posttranslational modification of proteins and is catalyzed by lysine acetyltransferases, while lysine deacetylases remove acetyl groups. Among the deacetylases, the sirtuins are NAD(+)-dependent enzymes, which modulate gene silencing, DNA damage repair, and several metabolic processes. As sirtuin-specific inhibitors have been proposed as drugs for inhibiting the proliferation of tumor cells, in this study, we investigated the role of these inhibitors in the growth and differentiation of Trypanosoma cruzi, the agent of Chagas disease. We found that the use of salermide during parasite infection prevented growth and initial multiplication after mammalian cell invasion by T. cruzi at concentrations that did not affect host cell viability. In addition, in vivo infection was partially controlled upon administration of salermide. There are two sirtuins in T. cruzi, TcSir2rp1 and TcSir2rp3. By using specific antibodies and cell lines overexpressing the tagged versions of these enzymes, we found that TcSir2rp1 is localized in the cytosol and TcSir2rp3 in the mitochondrion. TcSir2rp1 overexpression acts to impair parasite growth and differentiation, whereas the wild-type version of TcSir2rp3 and not an enzyme mutated in the active site improves both. The effects observed with TcSir2rp3 were fully reverted by adding salermide, which inhibited TcSir2rp3 expressed in Escherichia coli with a 50% inhibitory concentration (IC50) ± standard error of 1 ± 0.5 μM. We concluded that sirtuin inhibitors targeting TcSir2rp3 could be used in Chagas disease chemotherapy., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)
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- 2015
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24. Stress induces changes in the phosphorylation of Trypanosoma cruzi RNA polymerase II, affecting its association with chromatin and RNA processing.
- Author
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Rocha AA, Moretti NS, and Schenkman S
- Subjects
- Phosphorylation, Protozoan Proteins genetics, RNA Polymerase II genetics, RNA Splicing, Transcription, Genetic, Chromatin metabolism, Heat-Shock Response, Protein Processing, Post-Translational, Protozoan Proteins metabolism, RNA Polymerase II metabolism, RNA, Messenger metabolism, Trypanosoma cruzi metabolism
- Abstract
The phosphorylation of the carboxy-terminal heptapeptide repeats of the largest subunit of RNA polymerase II (Pol II) controls several transcription-related events in eukaryotes. Trypanosomatids lack these typical repeats and display an unusual transcription control. RNA Pol II associates with the transcription site of the spliced leader (SL) RNA, which is used in the trans-splicing of all mRNAs transcribed on long polycistronic units. We found that Trypanosoma cruzi RNA Pol II associated with chromatin is highly phosphorylated. When transcription is inhibited by actinomycin D, the enzyme runs off from SL genes, remaining hyperphosphorylated and associated with polycistronic transcription units. Upon heat shock, the enzyme is dephosphorylated and remains associated with the chromatin. Transcription is partially inhibited with the accumulation of housekeeping precursor mRNAs, except for heat shock genes. DNA damage caused dephosphorylation and transcription arrest, with RNA Pol II dissociating from chromatin although staying at the SL. In the presence of calyculin A, the hyperphosphorylated form detached from chromatin, including the SL loci. These results indicate that in trypanosomes, the unusual RNA Pol II is phosphorylated during the transcription of SL and polycistronic operons. Different types of stresses modify its phosphorylation state, affecting pre-RNA processing., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)
- Published
- 2014
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