Browsing by Author "Arantes, Rosa Maria Esteves"

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    Deficiency of Pkc1 activity affects glycerol metabolism in Saccharomices cerevisiae.
    (2005) Gomes, Katia das Neves; Freitas, Suzy Magaly Alves Cabral de; Pais, Thiago Martins; Fietto, Juliana Lopes Rangel; Totola, Antonio Helvecio; Arantes, Rosa Maria Esteves; Martins, António; Lucas, Cândida Manuel Ribeiro Simões; Schuller, Dorit; Casal, Margarida; Castro, Ieso de Miranda; Fietto, Luciano Gomes; Rogelio, Lopes Brandão
    Protein kinase C is apparently involved in the control of many cellular systems: the cell wall integrity pathway, the synthesis of ribosomes, the appropriated reallocation of transcription factors under specific stress conditions and also the regulation of N-glycosylation activity. All these observations suggest the existence of additional targets not yet identified. In the context of the control of carbon metabolism, previous data had demonstrated that Pkc1p might play a central role in the control of cellular growth and metabolism in yeast. In particular, it has been suggested that it might be involved in the derepression of genes under glucose-repression by driving an appropriated subcellular localization of transcriptional factors, such as Mig1p. In this work, we show that a pkc1D mutant is unable to grow on glycerol because it cannot perform the derepression of the GUT1 gene that encodes glycerol kinase. Additionally, active transport is also partially affected. Using this phenotype, we were able to isolate a new pkc1D revertant. We also isolated two transformants identified as the nuclear exportin Msn5 and the histone deacetylase Hos2 extragenic suppressors of this mutation. Based on these results, we postulate that Pkc1p may be involved in the control of the cellular localization and/or regulation of the activity of nuclear proteins implicated in gene expression.
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    Desenvolvimento e caracterização do modelo de infecção de leishmaniose mucocutânea no camundongo deficientes do receptor 1 do TNF- α e avaliação das lesões cutâneas crônicas nestes animais infectados com L. major após o tratamento com células mononucleares purificadas da medula óssea.
    (Programa de Pós-Graduação em Ciências Biológicas. Núcleo de Pesquisas em Ciências Biológicas, Pró-Reitoria de Pesquisa e Pós Graduação, Universidade Federal de Ouro Preto., 2012) Almeida, Daniel Manzoni de; Vieira, Leda Quercia; Arantes, Rosa Maria Esteves
    A leishmaniose é causada por parasitas do gênero Leishmania. A forma mucocutânea da leishmaniose apresenta lesões crônicas com baixo número de parasitas no local da infecção causando uma resposta inflamatória exagerada. Camundongos TNFR1 KO, quando infectados com L. major, conseguem controlar o crescimento do parasita no local da infecção, porém mantém um intenso infiltrado inflamatório quando comparados aos animais selvagens. O objetivo desse estudo foi a caracterização das lesões cutâneas crônicas desenvolvidas nos animais TNFR1 KO infectados por L. major e a análise do efeito da terapia celular nessas lesões. Os camundongos selvagens e TNFR1 KO foram inoculados na pata com L. major e foram acompanhados por 15 semanas de infecção para análise do perfil da imunopatologia desenvolvida. Os resultados mostraram que as lesões crônicas dos camundongos TNFR1 KO infectados por L. major apresentaram níveis elevados de citocinas pró-inflamatórias (IFN-γ, TNF-α e IL-17) e das quimiocinas CCL2 e CCL5 quando comparados aos animais selvagens. A persistência dessas lesões em camundongos TNFR1 KO é devida a um infiltrado inflamatório intenso e persistente, rico de células Ly6G+ e TCD8+ no local da infecção. Para testar a terapia celular, os camundongos TNFR1 KO foram tratados na fase crônica (15 semanas após a infecção) com três preparados de células mononucleares purificadas da medula óssea, semanalmente, por via endovenosa e as análises realizadas um e dois meses após o tratamento. O tratamento com células mononucleares derivadas da medula óssea mostrou eficácia no controle das lesões crônicas dos camundongos TNFR1 KO. Após sete dias da transferência, as células transferidas foram localizadas nas lesões diferenciadas em células CD11c+ e MHCII+; Após um e dois meses dos tratamentos, as lesões reduzidas apresentaram aumento da expressão de IL-10 e diminuição da expressão de IL-17; as análises histológicas mostraram porcentagens reduzidas de células polimorfonucleares nas lesões dos animais tratados com as células quando comparados aos animais tratados com veículo. Esses resultados mostraram que as células mononucleares purificadas da medula óssea promovem o controle das lesões crônicas desenvolvidas em camundongos TNFR1 KO infectados.
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    Enteric neuronal damage, intramuscular denervation and smooth muscle phenotype changes as mechanisms of chagasic megacolon : evidence from a long - term murine model of Tripanosoma cruzi infection.
    (2016) Campos, Camila França; Cangussú, Silvia Dantas; Duz, Ana Luiza Cassin; Cartelle, Christiane Teixeira; Noviello, Maria de Lourdes; Veloso, Vanja Maria; Bahia, Maria Terezinha; Leite, Camila Megale Almeida; Arantes, Rosa Maria Esteves
    We developed a novel murine model of long-term infection with Trypanosoma cruzi with the aim to elucidate the pathogenesis of megacolon and the associated adaptive and neuromuscular intestinal disorders. Our intent was to produce a chronic stage of the disease since the early treatment should avoid 100% mortality of untreated animals at acute phase. Treatment allowed animals to be kept infected and alive in order to develop the chronic phase of infection with low parasitism as in human disease. A group of Swiss mice was infected with the Y strain of T. cruzi. At the 11th day after infection, a sub-group was euthanized (acute-phase group) and another sub-group was treated with benznidazole and euthanized 15 months after infection (chronic-phase group). Whole colon samples were harvested and used for studying the histopathology of the intestinal smooth muscle and the plasticity of the enteric nerves. In the acute phase, all animals presented inflammatory lesions associated with intense and diffuse parasitism of the muscular and submucosa layers, which were enlarged when compared with the controls. The occurrence of intense degenerative inflammatory changes and increased reticular fibers suggests inflammatoryinduced necrosis of muscle cells. In the chronic phase, parasitism was insignificant; however, he architecture of Aüerbach plexuses was focally affected in the inflamed areas, and a significant decrease in the number of neurons and in the density of intramuscular nerve bundles was detected. Other changes observed included increased thickness of the colon wall, diffuse muscle cell hypertrophy, and increased collagen deposition, indicating early fibrosis in the damaged areas. Mast cell count significantly increased in the muscular layers. We propose a model for studying the long-term (15 months) pathogenesis of Chagasic megacolon in mice that mimics the human disease, which persists for several years and has not been fully elucidated. We hypothesize that the long-term inflammatory process mediates neuronal damage and intramuscular and intramural denervation, leading to phenotypic changes in smooth muscle cells associated with fibrosis. These long-term structural changes may represent the basic mechanism for the formation of the Chagasic megacolon.
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    High-density-immune-complex regulatory macrophages promote recovery of experimental colitis in mice.
    (2021) Lopes, Tamara Cristina Moreira; Almeida, Gregório Guilherme; Souza, Izabela Aparecida; Borges, Diego Costa; Lima, Wanderson Geraldo de; Prazeres, Pedro Henrique Dias Moura; Birbrair, Alexander; Arantes, Rosa Maria Esteves; Mosser, David M.; Gonçalves, Ricardo
    Macrophages not only play a fundamental role in the pathogenesis of inflam- matory bowel disease (IBD), but they also play a major role in preserving intestinal homeo- stasis. In this work, we evaluated the role of macrophages in IBD and investigated whether the functional reprogramming of macrophages to a very specific phenotype could decrease dis- ease pathogenesis. Thus, macrophages were stimulated in the presence of high-density immune complexes which strongly upregulate their production of IL-10 and downregulate pro-inflammatory cytokines. The transfer of these high-density-immune-complex regulatory macrophages into mice with colitis was examined as a potential therapy proposal to control the disease. Animals subjected to colitis induction received these high-density-immune- complex regulatory macrophages, and then the Disease Activity Index (DAI), and macro- scopic and microscopic lesions were measured. The treated group showed a dramatic improvement in all parameters analyzed, with no difference with the control group. The colon was macroscopically normal in appearance and size, and microscopically colon architecture was preserved. The immunofluorescence migration assay showed that these cells migrated to the inflamed intestine, being able to locally produce the cytokine IL-10, which could explain the dramatic improvement in the clinical and pathological condition of the animals. Thus, our results demonstrate that the polarization of macrophages to a high IL-10 producer profile after stimulation with high-density immune complexes was decisive in controlling experimental colitis, and that macrophages are a potential therapeutic target to be explored in the control of colitis.
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    Histopathology of Leishmania major infection : revisiting L. major histopathology in the ear dermis infection model.
    (2009) Cangussú, Silvia Dantas; Souza, Carolina Carvalho de; Campos, Camila França; Vieira, Leda Quercia; Afonso, Luís Carlos Crocco; Arantes, Rosa Maria Esteves
    We describe the relationship between lesion outcome and histopathological hallmarks in susceptible (BALB/c) and resistant (C57BL/6 and IL-4-deficient BALB/c) mouse strains over the course of a 12-week-infection with Leishmania major in the ear. The infiltration of mononuclear cells and polymorphonuclear cells occurred within 6 h and mononuclear cells predominated one week post-infection. Permissive intracellular growth of the pathogen was associated with non-healing lesions. In contrast, tissue damage and clearance of the parasite was observed in healing lesions and was associated with inducible nitric oxide synthase expression. The identification of the struc¬tural components of tissue reaction to the parasite in this study furthers our understanding of subjacent immune effector mechanisms.
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    Immune response induced by New World Leishmania species in C57BL/6 mice.
    (2004) Maioli, Tatiani Uceli; Takane, Erica; Arantes, Rosa Maria Esteves; Fietto, Juliana Lopes Rangel; Afonso, Luís Carlos Crocco
    In the present study, C57BL/6 mice were inoculated with metacyclic Leishmania amazonensis or L. braziliensis promastigotes. While these animals were capable of controlling the infection by L. braziliensis, they developed chronic lesions with elevated numbers of parasites when infected by L. amazonensis. The differences in parasite control were associated with a decreased production of IFN-c and TNF by lymph node cells from L. amazonensis-infected mice. Furthermore, these animals presented decreased spleen cell proliferation and activation of germinal centers. In addition, we compared the ability of these parasites to hydrolyze extracellular ATP and AMP. While the ATPase activity of both parasite species was similar, L. amazonensis promastigotes presented higher AMP hydrolytic activity. This increased activity may lead to an increased production of adenosine, which has been shown to present anti-inflammatory activity and may thus be involved in the establishment of the immunosuppression observed in mice infected by L. amazonensis.
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    Interferon-y-induced nitric oxide causes intrinsic intestinal denervation in Trypanosoma cruzi-infected mice.
    (2004) Arantes, Rosa Maria Esteves; Marche, Homero H. F.; Bahia, Maria Terezinha; Cunha, Fernando de Queiroz; Rossi, Marcos Antonio; Silva, João Santana da
    In this study, the role of nitric oxide (NO) in neuronal destruction during acute-phase Trypanosoma cruzi infection was evaluated in male C57BL/6 (WT, wildtype) mice and knockout mice [inducible nitric oxide synthase (iNOS)_/_ and interferon (IFN)_/_]. Selected animals were infected by intraperitoneal injection of 100 trypomastigote forms of the Y strain of T. cruzi. Others were injected intraperitoneally with an equal volume of saline solution and served as controls. Our findings support those of previous studies regarding myenteric denervation in acute-phase T. cruzi infection. In addition, we clearly demonstrate that, despite the fact that parasite nests and similar inflammatory infiltrate in the intestinal wall were more pronounced in infected iNOS_/_ mice than in infected WT mice, the former presented no reduction in myenteric plexus neuron numbers. Neuronal nerve profile expression, as revealed by the general nerve marker PGP 9.5, was preserved in all knockout animals. Infected IFN_/_ mice suffered no significant neuronal loss and there was no inflammatory infiltrate in the intestinal wall. On days 5 and 10 after infection, iNOS activity was greater in infected WT mice than in controls, whereas iNOS activity in infected knockout mice remained unchanged. These findings clearly demonstrate that neuronal damage does not occur in NO-impaired infected knockout mice, regardless of whether inflammatory infiltrate is present (iNOS_/_) or absent (IFN_/_). In conclusion, our observations strongly indicate that myenteric denervation in acutephase T. cruzi infection is because of IFN-_-elicited NO production resulting from iNOS activation in the inflammatory foci along the intestinal wall.
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    Interferon-γ induced nitric oxide mediates in vitro neuronal damage by Trypanosoma cruzi-infected macrophages.
    (2007) Leite, Camila Megale Almeida; Galvão, Lúcia Maria da Cunha; Afonso, Luís Carlos Crocco; Cunha, Fernando de Queiroz; Arantes, Rosa Maria Esteves
    Neuronal lesions and peripheral denervation in Chagas' disease are related to local inflammation; however, the pathogenic mechanisms of neuronal lesions in the heart and megavisceras are still unclear. We investigated the involvement of nitric oxide (NO) on neuronal lesion in co-cultures of neurons and macrophages. Trypanosoma cruzi-infected and interferon-γ (IFN-γ)-activated co-cultures of neurons and wildtype (WT) macrophages showed significant reduction of both neuronal survival and neurite density. These findings correlated with the levels of NO and the expression of inducible nitric oxide synthase (iNOS). Accordingly, neuronal survival rate in the co-cultures was recovered to control levels by treatment of the cultures with the iNOS inhibitor, aminoguanidine. Moreover, neither neuronal survival nor the neurite density was affected in the co-cultures when the macrophages were harvested from iNOS-deficient mice. These results demonstrate that iNOS-derived NO is the major molecule involved in neuronal damage mechanism in our in vitro model of Chagas' disease neuropathology.
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    Neuronal parasitism, early myenteric neurons depopulation and continuous axonal networking damage as underlying mechanisms of the experimental intestinal Chagas' disease.
    (2020) Ricci, Mayra Fernanda; Béla, Samantha Ribeiro; Moraes, Michele Macedo; Bahia, Maria Terezinha; Mazzeti, Ana Lia; Oliveira, Anny Carolline Silva; Oliveira, Luciana Souza de; Radi, Rafael; Piacenza, Lucía; Arantes, Rosa Maria Esteves
    There is a growing consensus that the balance between the persistence of infection and the host immune response is crucial for chronification of Chagas heart disease. Extrapolation for chagasic megacolon is hampered because research in humans and animal models that reproduce intestinal pathology is lacking. The parasite-host relationship and its consequence to the disease are not well-known. Our model describes the temporal changes in the mice intestine wall throughout the infection, parasitism, and the development of megacolon. It also presents the consequence of the infection of primary myenteric neurons in culture with Trypanosoma cruzi (T. cruzi). Oxidative neuronal damage, involving reactive nitrogen species induced by parasite infection and cytokine production, results in the denervation of the myenteric ganglia in the acute phase. The long-term inflammation induced by the parasite’s DNA causes intramuscular axonal damage, smooth muscle hypertrophy, and inconsistent innervation, affecting contractility. Acute phase neuronal loss may be irreversible. However, the dynamics of the damages revealed herein indicate that neuroprotection interventions in acute and chronic phases may help to eradicate the parasite and control the inflammatory-induced increase of the intestinal wall thickness and axonal loss. Our model is a powerful approach to integrate the acute and chronic events triggered by T. cruzi, leading to megacolon.
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    The endogenous cytokine profile and nerve fibre density in mouse ear Leishmania major-induced lesions related to nociceptive thresholds.
    (2013) Cangussú, Silvia Dantas; Souza, Carolina Carvalho de; Castro, Maria Salete de Abreu; Vieira, Leda Quercia; Cunha, Fernando de Queiroz; Afonso, Luís Carlos Crocco; Arantes, Rosa Maria Esteves
    Several reports have shown that cutaneous leishmaniasis lesions are painless, suggesting that Leishmania infection interferes with pain perception. Comparisons of inflammation-induced hyperalgesia between BALB/c and C57BL/6 mice have been little explored in the literature, and comparative data regarding nociception in leishmaniasis are non-existent. In susceptible BALB/c mice and resistant C57BL/6 mice that were intradermally inoculated with a low dose of Leishmania major in the ear, we investigated the variation in nociception over a 12-wk period post-infection and this variation’s association with the structure of nerve fibres and the presence of endogenous cytokines that are classically considered hyper- or hyponociceptive. Infected BALB/c mice presented susceptibility and severe lesions. Infected C57BL/6 mice exhibited resistance and healing lesions. The immune response involved pro- and anti-inflammatory cytokine secretion, respectively. The infection-induced hypoalgesia in BALB/c mice after wks 9 was accompanied by decreased levels of IL-6 and IL-10 in ear tissue with intact nerves. C57BL/6 mice showed short-lived hyperalgesia in wks 2, which was related to increased local levels of IL-6, KC/CXCL-1, TNF-a and IL-10 and a decrease in nerve density. The increase in pro-inflammatory cytokine IL-6, KC/CXCL-1 and TNF-a levels during hyperalgesia suggested a role for these mediators in afferent nerve sensitisation, which was secondary to the inflammatory damage of nerve fibres stained by PGP 9.5. In contrast, the mechanisms of hypoalgesia may include the downregulation of cytokines, the preservation of the structure of nerve endings, and as yet uninvestigated unidentified differences in neurotransmitter release or a direct role of the parasites in the context of the progressive and permissive inflammatory response of BALB/c mice.
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    Variation in neuronal differentiation of a newly isolated mouse embryonic stem cell line : a detailed immunocytochemistry study.
    (2012) Tavares, Rubens Lene Carvalho; Cortes, Paloma Alvarenga; Azevedo, Camila Issa de; Cangussú, Silvia Dantas; Camargos, Aroldo Fernando; Arantes, Rosa Maria Esteves
    Neural precursor differentiation from mouse ES (embryonic stem) cells have been demonstrated using EB (embryoid body), co-culture on stromal feeder layers, and in the absence of external inducing signals. Most of available mouse ES cell original research articles have worked with only six different cell lines. Our goals were to isolate one new mouse ES lineage, and perform a detailed immunocytochemistry study during neural differentiation, making use of an EB strategy protocol following the generation of neural progenitors, glial cells and postmitotic neurons. The dynamics of differentiation of ES cell derived neuronal precursors into differentiated glia cells and neurons were followed in vitro and correlated to exposure to specific elements of feeder medium. Morphological aspects of generated cellular types, including its immunocytochemical expression of differentiation markers were studied. Immuno-positivity against b-III tubulin, PGP and TH (tyrosine hydroxylase) was observed from stage I. Approximately 80% of cells were positive for TH at stage I. The first glial cell type appears in stage III. TH, PGP or b-III tubulin-positive cells with neuronal typical morphology only being seen in stage III when TH-positive cells corresponded to approximately 12% of total cells. Variations among other literature findings can be explained by the choice we made to use a newly isolated ES cell line. As colonies may behave differently during neuronal differentiation, it reinforces the necessity of studying original ES cell lines.
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    Virulence in murine model shows the existence of two distinct populations of Brazilian vaccinia virus strains.
    (2008) Ferreira, Jaqueline Maria Siqueira; Drumond, Betânia Paiva; Guedes, Maria Isabel Maldonado Coelho; Xavier, Marcelo Antônio Pascoal; Leite, Camila Megale Almeida; Arantes, Rosa Maria Esteves; Mota, Bruno Eduardo Fernandes; Abrahão, Jônatas Santos; Alves, Pedro Augusto; Oliveira, Fernando Meireles; Ferreira, Paulo César Peregrino; Bonjardim, Cláudio Antônio; Lobato, Zélia Inês Portela; Kroon, Erna Geessien
    Brazilian Vaccinia virus had been isolated from sentinel mice, rodents and recently from humans, cows and calves during outbreaks on dairy farms in several rural areas in Brazil, leading to high economic and social impact. Some phylogenetic studies have demonstrated the existence of two different populations of Brazilian Vaccinia virus strains circulating in nature, but little is known about their biological characteristics. Therefore, our goal was to study the virulence pattern of seven Brazilian Vaccinia virus strains. Infected BALB/c mice were monitored for morbidity, mortality and viral replication in organs as trachea, lungs, heart, kidneys, liver, brain and spleen. Based on the virulence potential, the Brazilian Vaccinia virus strains were grouped into two groups. One group contained GP1V, VBH, SAV and BAV which caused disease and death in infected mice and the second one included ARAV, GP2V and PSTV which did not cause any clinical signals or death in infected BALB/ c mice. The subdivision of Brazilian Vaccinia virus strains into two groups is in agreement with previous genetic studies. Those data reinforce the existence of different populations circulating in Brazil regarding the genetic and virulence characteristics.