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The interaction between macrophages and Cryptococcus neoformans (Cn) can result in fungal killing or intracellular replication. The macrophage optimal response requires the specific recognition of fungal molecular structures by a variety... more
The interaction between macrophages and Cryptococcus neoformans (Cn) can result in fungal killing or intracellular replication. The macrophage optimal response requires the specific recognition of fungal molecular structures by a variety of pattern-recognition receptors (PRRs) receptors, mainly TLRs and CLRs.. We report that zymosan (b-glucan)-stimulated macrophages enhanced the antifungal activity against Cn. This activity depends primarily on Dectin-1 activation, with minor contribution of complement receptor 3 and/or TLR2. b-glucan-stimulation also up-regulates macrophage genes associated with an effective immune response, activation of caspase 1, enhanced IL-1b secretion and phagossome acidification. Hence, macrophage permissiveness to Cn intracellular replication is a consequence of interference by the capsule in the recognition between cell wall antigens and PPRs. Our results reveal a new role for the capsule in virulence by establishing that it prevents macrophage activation and thus prevents control of intracellular infection. Therapeutic approaches that promote macrophage activation through stimulation of Dectin-1 may be useful as adjunctive therapy for cryptococcosis.
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Paracoccidioides brasiliensis is the major etiologic agent of Paracoccidioidomycosis (PCM), the most frequent human deep mycosis in Latin America. It is proposed that masking of β-glucan in P. brasiliensis cell wall is a critical... more
Paracoccidioides brasiliensis is the major etiologic agent of Paracoccidioidomycosis (PCM), the most frequent human deep mycosis in Latin America. It is proposed that masking of β-glucan in P. brasiliensis cell wall is a critical virulence factor that contributes to the development of a chronic disease characterized by a long period of treatment, which is usually toxic. In this context, the search for immunomodulatory agents for therapeutic purposes is highly desirable. One strategy is to use pattern recognition receptors (PRRs) ligands to stimulate the immune response mediated by phagocytes. Here, we sought to evaluate if Zymosan, a β-glucan-containing ligand of the PRRs Dectin-1/TLR-2, would enhance phagocyte function and the immune response of mice challenged with P. brasiliensis. Dendritic cells (DCs) infected with P. brasiliensis and treated with Zymosan showed improved secretion of several proinflammatory cytokines and expression of maturation markers. In addition, when cocultured with splenic lymphocytes, these cells induced the production of a potential protective type 1 and 17 cytokine patterns. In macrophages, Zymosan ensued a significant fungicidal activity associated with nitric oxide production and phagolysosome acidification. Importantly, we observed a protective effect of Zymosan-primed DCs delivered intranasally in experimental pulmonary PCM. Overall, our findings support the potential use of β-glucan-containing compounds such as Zymosan as an alternative or complementary antifungal therapy. LAY SUMMARY We report for the first time that Paracoccidioides brasiliensis-infected phagocytes treated with Zymosan (cell wall extract from bakers' yeast) show enhanced cytokine production, maturation, and fungal killing. Also, Zymosan-primed phagocytes induce a protective immune response in infected mice.
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Current antifungal drugs present poor effectiveness and there is no available vaccine for fungal infections. Thus, novel strategies to treat or prevent invasive mycosis, such as cryptococcosis, are highly desirable. One strategy is the... more
Current antifungal drugs present poor effectiveness and there is no available vaccine for fungal infections. Thus, novel strategies to treat or prevent invasive mycosis, such as cryptococcosis, are highly desirable. One strategy is the use of immunomodulators of polysaccharide nature isolated from mushrooms. The purpose of the present work was to evaluate the immunostimulatory activity of β-(1,3)-glucan-containing exopolysaccharides (EPS) from the edible mushrooms Auricularia auricula in phagocytes and mice infected with Cryptococcus neoformans. EPS triggered macrophages and dendritic cell activation upon binding to Dectin-1, a pattern recognition receptor of the C-type lectin receptor family. Engagement of Dectin-1 culminated in pro-inflammatory cytokine production and cell maturation via its canonical Syk-dependent pathway signaling. Furthermore, upon EPS treatment, M2-like phenotype macrophages, known to support intracellular survival and replication of C. neoformans, repolarize to M1 macrophage pattern associated with enhanced production of the microbicidal molecule nitric oxide that results in efficient killing of C. neoformans. Treatment with EPS also upregulated transcript levels of genes encoding products associated with host protection against C. neoformans and Dectin-1 mediated signaling in macrophages. Finally, orally administrated β-glucan-containing EPS from A. auricular enhanced the survival of mice infected with C. neoformans. In conclusion, the results demonstrate that EPS from A. auricula exert immunostimulatory activity in phagocytes and induce host protection against C. neoformans, suggesting that polysaccharides from this mushroom may be promising as an adjuvant for vaccines or antifungal therapy.
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The interaction between macrophages and Cryptococcus neoformans (Cn) can result in fungal killing or intracellular replication. The macrophage optimal response requires the specific recognition of fungal molecular structures by a variety... more
The interaction between macrophages and Cryptococcus neoformans (Cn) can result in fungal killing or intracellular replication. The macrophage optimal response requires the specific recognition of fungal molecular structures by a variety of pattern-recognition receptors (PRRs) receptors, mainly TLRs and CLRs.. We report that zymosan (b-glucan)-stimulated macrophages enhanced the antifungal activity against Cn. This activity depends primarily on Dectin-1 activation, with minor contribution of complement receptor 3 and/or TLR2. b-glucan-stimulation also up-regulates macrophage genes associated with an effective immune response, activation of caspase 1, enhanced IL-1b secretion and phagossome acidification. Hence, macrophage permissiveness to Cn intracellular replication is a consequence of interference by the capsule in the recognition between cell wall antigens and PPRs. Our results reveal a new role for the capsule in virulence by establishing that it prevents macrophage activation ...
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ABSTRACTVirulence ofCryptococcus neoformansfor mammals, and in particular its intracellular style, was proposed to emerge from evolutionary pressures on its natural environment by protozoan predation, which promoted the selection of... more
ABSTRACTVirulence ofCryptococcus neoformansfor mammals, and in particular its intracellular style, was proposed to emerge from evolutionary pressures on its natural environment by protozoan predation, which promoted the selection of strategies that allow intracellular survival in macrophages. In fact,Acanthamoeba castellaniiingests yeast cells, which then can replicate intracellularly. In addition, most fungal factors needed to establish infection in the mammalian host are also important for survival within the amoeba. To better understand the origin ofC. neoformansvirulence, we compared the transcriptional profile of yeast cells internalized by amoebae and murine macrophages after 6 h of infection. Our results showed 656 and 293 genes whose expression changed at least 2-fold in response to the intracellular environments of amoebae and macrophages, respectively. Among the genes that were found in both groups, we focused on open reading frame (ORF) CNAG_05662, which was potentially r...
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ABSTRACT. Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis, is a dimorphic fungus, which is found as mycelia at 22-26°C and as yeasts at 37°C. A remarkable feature common to several pathogenic fungi is their... more
ABSTRACT. Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis, is a dimorphic fungus, which is found as mycelia at 22-26°C and as yeasts at 37°C. A remarkable feature common to several pathogenic fungi is their ability to differentiate from mycelium to yeast morphologies, or vice-versa. Although P. brasiliensis is a recognized pathogen for humans, little is known about its virulence genes. In this sense, we performed a search for putative virulence genes in the P. brasiliensis transcriptome. BLAST comparative analyses were done among P. brasilienses assembled expressed sequence tags (PbAESTs) and the sequences deposited in GenBank. As a result, the putative virulence PbAESTs were grouped into five classes, metabolism-, cell wall-, detoxification-related, secreted factors, and other determinants. Among these, we have identified orthologs of the glyoxylate cycle enzymes, a metabolic pathway involved in the virulence of bacteria and fungi. Besides the previousl...
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Limited information is available regarding the modulation of genes involved in the innate host response to Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis. Therefore, we sought to characterize, for the first... more
Limited information is available regarding the modulation of genes involved in the innate host response to Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis. Therefore, we sought to characterize, for the first time, the transcriptional profile of murine bone marrow-derived dendritic cells (DCs) at an early stage following their initial interaction with P. brasiliensis. DCs connect innate and adaptive immunity by recognizing invading pathogens and determining the type of effector T-cell that mediates an immune response. Gene expression profiles were analyzed using microarray and validated using real-time RT-PCR and protein secretion studies. A total of 299 genes were differentially expressed, many of which are involved in immunity, signal transduction, transcription and apoptosis. Genes encoding the cytokines IL-12 and TNF-a, along with the chemokines CCL22, CCL27 and CXCL10, were up-regulated, suggesting that P. brasiliensis induces a potent proinflammator...
Research Interests: Immune response, Pattern Recognition, Biology, Medicine, Dendritic Cells, and 15 moreBiological Sciences, Mice, Adaptive Immunity, Protein Secretion, Animals, Male, Dendritic cell, Microarray Analysis, Physiological Stress Markers, Paracoccidioides, Gene Expression Regulation, Gene expression profiling, Mannose receptor, Differential expression, and Medical and Health Sciences
Since its first description in 2002 [1], the inflammasome has been implicated in the mecha-nisms underlying a growing number of infectious, autoimmune, and metabolic diseases [2]. Regarding infectious processes, several studies have shown... more
Since its first description in 2002 [1], the inflammasome has been implicated in the mecha-nisms underlying a growing number of infectious, autoimmune, and metabolic diseases [2]. Regarding infectious processes, several studies have shown the involvement of this critical component of innate immunity in the outcome of infection with nearly every class of microbe, including fungi [3]. Innate immunity is the frontline of defense against infection and relies on the ability of its main players (phagocytes and epithelial barriers) to detect conserved compo-nents of microbes or pathogen-associated molecular patterns (PAMPs). In fungi, the carbohy-drate polymers of the cell wall, such as chitin, β-glucan, and mannan are the major PAMPs recognized by the host’s innate immune cells; this recognition occurs via germline-encoded receptors termed pattern recognition receptors (PRRs) [4]. In addition to PAMPs, endogenous molecules associated with damaged host cells, or damage-associated molecular...
The earliest interaction between macrophages and Paracoccidioides brasiliensis is particularly important in paracoccidioidomycosis (PCM) progression, and surface proteins play a central role in this process. The present study investigated... more
The earliest interaction between macrophages and Paracoccidioides brasiliensis is particularly important in paracoccidioidomycosis (PCM) progression, and surface proteins play a central role in this process. The present study investigated the contribution of β2 integrin in P. brasiliensis-macrophage interaction and PCM progression. We infected β2-low expression (CD18low) and wild type (WT) mice with P. brasiliensis 18. Disease progression was evaluated for fungal burden, lung granulomatous lesions, nitrate levels, and serum antibody production. Besides, the in vitro capacity of macrophages to internalize and kill fungal yeasts was investigated. Our results revealed that CD18low mice infected with Pb18 survived during the time analyzed; their lungs showed fewer granulomas, a lower fungal load, lower levels of nitrate, and production of high levels of IgG1 in comparison to WT animals. Our results revealed that in vitro macrophages from CD18low mice slowly internalized yeast cells, sho...
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Cryptococcus neoformans is a human pathogenic fungus that mainly afflicts immunocompromised patients. One of its virulence strategies is the production of extracellular vesicles (EVs), containing cargo with immunomodulatory properties. We... more
Cryptococcus neoformans is a human pathogenic fungus that mainly afflicts immunocompromised patients. One of its virulence strategies is the production of extracellular vesicles (EVs), containing cargo with immunomodulatory properties. We evaluated EV’s characteristics produced by capsular and acapsular strains of C. neoformans (B3501 and ΔCap67, respectively) growing in nutritionally poor or rich media and co-cultures with bone marrow-derived macrophages or dendritic cells from C57BL/6 mice. EVs produced under a poor nutritional condition displayed a larger hydrodynamic size, contained more virulence compounds, and induced a more robust inflammatory pattern than those produced in a rich nutritional medium, independently of strain. We treated infected mice with EVs produced in the rich medium, and the EVs inhibited more genes related to the inflammasome than untreated infected mice. These findings suggest that the EVs participate in the pathogenic processes that result in the dissem...
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Most people infected with the fungus Paracoccidioides spp. do not get sick, but approximately 5% develop paracoccidioidomycosis. Understanding how host immunity determinants influence disease development could lead to novel preventative... more
Most people infected with the fungus Paracoccidioides spp. do not get sick, but approximately 5% develop paracoccidioidomycosis. Understanding how host immunity determinants influence disease development could lead to novel preventative or therapeutic strategies; hence, we used two mouse strains that are resistant (A/J) or susceptible (B10.A) to P. brasiliensis to study how dendritic cells (DCs) respond to the infection. RNA sequencing analysis showed that the susceptible strain DCs remodeled their transcriptomes much more intensely than those from the resistant strain, agreeing with a previous model of more intense innate immunity response in the susceptible strain. Contrastingly, these cells also repress genes/processes involved in antigen processing and presentation, such as lysosomal activity and autophagy. After the interaction with P. brasiliensis, both DCs and macrophages from the susceptible mouse reduced the autophagy marker LC3-II recruitment to the fungal phagosome compar...
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Paracoccidioidomycosis (PCM) is a systemic mycosis caused by thermally dimorphic fungi of the genus Paracoccidioides that affects predominantly 30-60-year-old male rural workers. The main clinical forms of the disease are acute/subacute,... more
Paracoccidioidomycosis (PCM) is a systemic mycosis caused by thermally dimorphic fungi of the genus Paracoccidioides that affects predominantly 30-60-year-old male rural workers. The main clinical forms of the disease are acute/subacute, chronic (CF); almost all CF patients develop pulmonary fibrosis, and they also exhibit emphysema due to smoke. An important cytokine in this context, IL-1β, different from the others, is produced by an intracellular multimolecular complex called inflammasome that is activated by pathogens and/or host signs of damage. Inflammasome has been recognized for its contribution to chronic inflammatory diseases, from that, we hypothesized that this activation could be involved in paracoccidioidomycosis, contributing to chronic inflammation. While inflammasome activation has been demonstrated in experimental models of P. brasiliensis infection, no information is available in patients, leading us to investigate the participation of NLRP3-inflammasome machinery in CF/PCM patients from a Brazilian endemic area. Our findings showed increased priming in mRNA levels of NLRP3 inflammasome genes by monocytes of PCM patients in vitro than healthy controls. Similar intracellular protein expression of NLRP3, CASP-1, ASC, and IL-1β were also observed in freshly isolated monocytes of PCM patients and smoker controls. Increased expression of NLRP3 and ASC was observed in monocytes from PCM patients under hypoxia in comparison with smoker controls. For the first time, we showed that primed monocytes of CF-PCM patients were associated with enhanced expression of components of NLRP3-inflammasome due to smoke. Also, hypoxemia boosted this machinery. These findings reinforce the systemic low-grade inflammation activation observed in PCM during and after treatment.
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Cryptococcus neoformansis an encapsulated yeast that causes disease mainly in immunosuppressed hosts. It is considered a facultative intracellular pathogen because of its capacity to survive and replicate inside phagocytes, especially... more
Cryptococcus neoformansis an encapsulated yeast that causes disease mainly in immunosuppressed hosts. It is considered a facultative intracellular pathogen because of its capacity to survive and replicate inside phagocytes, especially macrophages. This capacity is heavily dependent on various virulence factors, particularly the glucuronoxylomannan (GXM) component of the polysaccharide capsule, that render the non- or poorly-activated macrophage ineffective against phagocytosed yeast. Strategies utilized by macrophages to prevent this scenario include pyroptosis (a rapid highly inflammatory cell death) and vomocytosis (the expulsion of the pathogen from the intracellular environment without lysis). Inflammasome activation in phagocytes is usually protective against fungal infections, including cryptococcosis. Nevertheless, recognition ofC. neoformansby inflammasome receptors requires specific changes in morphology or the opsonization of the yeast, impairing a proper inflammasome func...
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Fonsecaea pedrosoi is the main etiologic agent of chromoblastomycosis (CBM), one of the most prevalent subcutaneous mycosis in tropical and subtropical countries. CBM is a poorly characterized chronic infection that commonly starts after... more
Fonsecaea pedrosoi is the main etiologic agent of chromoblastomycosis (CBM), one of the most prevalent subcutaneous mycosis in tropical and subtropical countries. CBM is a poorly characterized chronic infection that commonly starts after transcutaneous inoculation of conidia and saprophytic hyphae of F. pedrosoi. Recently, we have shown that unlike conidia, hyphae and muriform cells (the parasitic morphotype) of F. pedrosoi promotes an intense inflammatory response pattern in vivo, which comprises the production of an inflammasome-derived cytokine, IL-1β. Nonetheless, the mechanisms underlying IL-1β production and maturation upon F. pedrosoi infection and its functional output in the course of CBM remains unknown. We show here that F. pedrosoi hyphae, differently from conidia, induce IL-1β secretion in both bone marrow-derived dendritic cells and macrophages. Using inhibitors and knockout cells, we demonstrated that the mechanisms underlying IL-1β production by hyphae-infected macro...
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A common theme across multiple fungal pathogens is their ability to impair the establishment of a protective immune response. Although early inflammation is beneficial in containing the infection, an uncontrolled inflammatory response is... more
A common theme across multiple fungal pathogens is their ability to impair the establishment of a protective immune response. Although early inflammation is beneficial in containing the infection, an uncontrolled inflammatory response is detrimental and may eventually oppose disease eradication. Chromoblastomycosis (CBM), a cutaneous and subcutaneous mycosis, caused by dematiaceous fungi, is capable of inducing a chronic inflammatory response. Muriform cells, the parasitic form of Fonsecaea pedrosoi, are highly prevalent in infected tissues, especially in long-standing lesions. In this study we show that hyphae and muriform cells are able to establish a murine CBM with skin lesions and histopathological aspects similar to that found in humans, with muriform cells being the most persistent fungal form, whereas mice infected with conidia do not reach the chronic phase of the disease. Moreover, in injured tissue the presence of hyphae and especially muriform cells, but not conidia, is ...
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The incidence of fungal infections has been increasing in the last decades, while the number of available antifungal classes remains the same. The natural and acquired resistance of some fungal species to available therapies, associated... more
The incidence of fungal infections has been increasing in the last decades, while the number of available antifungal classes remains the same. The natural and acquired resistance of some fungal species to available therapies, associated with the high toxicity of these drugs on the present scenario and makes an imperative of the search for new, more efficient and less toxic therapeutic choices. Antimicrobial peptides (AMPs) are a potential class of antimicrobial drugs consisting of evolutionarily conserved multifunctional molecules with both microbicidal and immunomodulatory properties being part of the innate immune response of diverse organisms. In this study, we evaluated 11 scorpion-venom derived non-disulfide-bridged peptides against Cryptococcus neoformans and Candida spp., which are important human pathogens. Seven of them, including two novel molecules, showed activity against both genera with minimum inhibitory concentration values ranging from 3.12 to 200 μM and an analogou...
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The commensal fungal pathogen Candida albicans is a leading cause of lethal systemic infections in immunocompromised patients. One of the main mechanisms of host immune evasion and virulence by this pathogen is the switch from yeast form... more
The commensal fungal pathogen Candida albicans is a leading cause of lethal systemic infections in immunocompromised patients. One of the main mechanisms of host immune evasion and virulence by this pathogen is the switch from yeast form to hyphal growth morphologies. Micro RNAs (miRNAs), a small regulatory non-coding RNA, has been identified as an important part of the immune response to a wide variety of pathogens. In general, miRNAs act by modulating the intensity of inflammatory responses. miRNAs act by base-paring binding to specific sequences of target mRNAs, generally causing their silencing through mRNA degradation or translational repression. To study the impact of C. albicans cell morphology upon host miRNA expression, we investigated the differential modulation of nine different immune response-related miRNAs in primary murine bone marrow-derived macrophages (BMDMs) exposed to either yeasts or hyphal forms of Candida albicans. Here, we show that the different growth morph...
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To evaluate the effects of metoclopramide on metalloproteinases (MMP) and interleukins (IL) gene expression in colonic anastomoses in rats. Eighty rats were divided into two groups for euthanasia on the 3rd or 7th postoperative day (POD),... more
To evaluate the effects of metoclopramide on metalloproteinases (MMP) and interleukins (IL) gene expression in colonic anastomoses in rats. Eighty rats were divided into two groups for euthanasia on the 3rd or 7th postoperative day (POD), then into two subgroups for sepsis induction or not, and then into subgroups to receive either metoclopramide or saline solution. Left colonic anastomosis were performed and then analyzed. On the 3rd POD, metoclopramide was associated with increased expression of MMP-1a, MMP-13, and TNF-α. On the 7th POD, the transcripts of all MMPs, TNF-α, IL-1β, IFN-γ, and IL-10 of the treated animals became negatively modulated. In the presence of sepsis, metoclopramide did not change MMPs and decreased IL-6, IL-1β, IFN-γ and IL-10 gene expression on the 3rd POD. On the 7th POD, increased expression of all MMPs, IFN-γ and IL-10 and negative modulated TNF-α and IL-6 gene expression. Administration of metoclopramide increased metalloproteinases and interleukins ge...
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Considering the importance of macrophages as the first line of defense against fungal infection and the different roles played by the two M1- and M2-like polarized macrophages, we decided to evaluate the effects ofParacoccidioides... more
Considering the importance of macrophages as the first line of defense against fungal infection and the different roles played by the two M1- and M2-like polarized macrophages, we decided to evaluate the effects ofParacoccidioides brasiliensisinfection on GM-CSF- and M-CSF-induced bone marrow-derived macrophages (BMM) from the A/J and B10.A mouse strains, an established model of resistance/susceptibility to PCM, respectively. Upon differentiation, the generated GM- or M-BMMs were characterized by morphological analyses, gene expression profiles, and cytokines production. Our main results demonstrate that GM-BMMs derived from A/J and B.10 produced high levels of pro- and anti-inflammatory cytokines that may contribute to generate an unbalanced early immune response. In accordance with the literature, the B10.A susceptible mice lineage has an innate tendency to polarize into M1-like phenotype, whereas the opposite phenotype occurs in A/J resistance mice. In this context, our data supp...
Research Interests: Immunology, Biology, Cytokines, Inflammation, Cell Adhesion, and 15 moreMacrophages, Medicine, Cell Differentiation, Mice, Animals, Male, Phenotype, Phagocytosis, Chemokines, Paracoccidioides, Bone Marrow Cells, Gene Expression Regulation, Gene expression profiling, paracoccidioidomycosis, and real time polymerase chain reaction
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Paracoccidioidomycosis (PCM), caused by Paracoccidioides species is a prevalent systemic and progressive mycosis that occurs in Latin America. It is caused by Paracoccidioides species. Immunization with dendritic cells transfected with a... more
Paracoccidioidomycosis (PCM), caused by Paracoccidioides species is a prevalent systemic and progressive mycosis that occurs in Latin America. It is caused by Paracoccidioides species. Immunization with dendritic cells transfected with a plasmid encoding the scFv (pMAC/PS-scFv) that mimics the main antigen of P. brasiliensis (gp43) confers protection in experimental PCM. DCs link innate and adaptive immunity by recognizing invading pathogens and selecting the type of effector T cell to mediate the immune response. Here, we showed that DC-pMAC/PS-scFv induces the activation of CD4+ and CD8+ T cells. Moreover, our results demonstrated that BALB/c mice infected with P. brasiliensis and treated with DC-pMAC/PS-scFv showed the induction of specific IgG production against gp43 and IFN-γ, IL-12 and IL-4 cytokines. Analysis of regional lymph nodes revealed increases in the expression of clec7a, myd88, tlr2, gata3 and tbx21, which are involved in the immune response. Taken together, our resu...
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Due to a lack of molecular tools that enable gain- and loss-of-function studies, much research with the fungi of the Paracoccidioides genus has consisted of gene expression studies. These have addressed the direct interaction of these... more
Due to a lack of molecular tools that enable gain- and loss-of-function studies, much research with the fungi of the Paracoccidioides genus has consisted of gene expression studies. These have addressed the direct interaction of these fungi with the mammalian host or their response to environmental stimuli of interest to the study of their adaptability to said host, such as the temperature shift that triggers dimorphic transition. In this chapter, we present a review of findings of host–pathogen interaction studies and what evidence they found of mechanisms whereby Paracoccidioides is able to overcome differences in environment and establish disease, and of how the host responds to the pathogen. In the first part, which deals with the pathogen response, expression studies have identified metabolic pathways genes thereof are upregulated when the fungi are exposed to different organs, as well as blood and derivatives, of mice and humans. Of note, these studies have suggested an important role, in the adaptation to host tissues, of a metabolic shift away from glycolysis and aerobic respiration and towards fermentative and non-aerobic ways of obtaining energy. With regard to the remarkable preference of the genus for male hosts, studies of the response of Paracoccidioides to oestradiol have suggested a role of Rho GTPases in the process. As for the second part, dealing with the host response to the fungus, despite the paucity of data, the few large-scale studies available offer evidence to support the model whereby Th1-driven immune responses are protective and disease is associated with Th2 and Th17 responses, in keeping with small-scale studies. Overall, gene expression studies have supplied a large amount of data that lack direct experimental confirmation but which keep revealing new research avenues.
Antimicrobial peptides (AMPs) are small molecules with microbicidal and immunoregulatory activities. In this study we evaluated the anti-inflammatory and antimicrobial activities of peptides ToAP3 and ToAP4, AMPs from the venom of the... more
Antimicrobial peptides (AMPs) are small molecules with microbicidal and immunoregulatory activities. In this study we evaluated the anti-inflammatory and antimicrobial activities of peptides ToAP3 and ToAP4, AMPs from the venom of the Brazilian scorpion Tityus obscurus. To test the peptides' activity, murine bone marrow-derived macrophages (BMDMs) or dendritic cells (BMDCs) were stimulated with peptides plus LPS to analyze their ability to modulate cytokine release as well as phenotypic markers. For antimicrobial analysis, we evaluated the indirect activity against macrophage-internalized Cryptococcus neoformans and direct activity against Mycobacterium massiliense. Our data demonstrate that they were able to reduce TNF-α and IL-1β transcript levels and protein levels for BMDM and BMDC. Furthermore, the reduction of TNF-α secretion, before LPS- inflammatory stimuli, is associated with peptide interaction with TLR-4. ToAP4 increased MHC-II expression in BMDC, while ToAP3 decreased co-stimulatory molecules such as CD80 and CD86. Although these peptides were able to modulate the production of cytokines and molecules associated with antigen presentation, they did not increase the ability of clearance of C. neoformans by macrophages. In antimicrobial analysis, only ToAP3 showed potent action against bacteria. Altogether, these results demonstrate a promising target for the development of new immunomodulatory and anti-bacterial therapies.
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Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis, is a dimorphic fungus, which is found as mycelia at 22-26 degrees C and as yeasts at 37 degrees C. A remarkable feature common to several pathogenic fungi is... more
Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis, is a dimorphic fungus, which is found as mycelia at 22-26 degrees C and as yeasts at 37 degrees C. A remarkable feature common to several pathogenic fungi is their ability to differentiate from mycelium to yeast morphologies, or vice-versa. Although P. brasiliensis is a recognized pathogen for humans, little is known about its virulence genes. In this sense, we performed a search for putative virulence genes in the P. brasiliensis transcriptome. BLAST comparative analyses were done among P. brasilienses assembled expressed sequence tags (PbAESTs) and the sequences deposited in GenBank. As a result, the putative virulence PbAESTs were grouped into five classes, metabolism-, cell wall-, detoxification-related, secreted factors, and other determinants. Among these, we have identified orthologs of the glyoxylate cycle enzymes, a metabolic pathway involved in the virulence of bacteria and fungi. Besides the pre...
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Paracoccidioides brasiliensis is the etiologic agent of paracoccidioidomycosis (PCM), the most prevalent systemic mycosis that is geographically confined to Latin America. The pro-inflammatory cytokine IL-1β that is mainly derived from... more
Paracoccidioides brasiliensis is the etiologic agent of paracoccidioidomycosis (PCM), the most prevalent systemic mycosis that is geographically confined to Latin America. The pro-inflammatory cytokine IL-1β that is mainly derived from the activation of the cytoplasmic multiprotein complex inflammasome is an essential host factor against opportunistic fungal infections; however, its role in infection with a primary fungal pathogen, such as P. brasiliensis, is not well understood. In this study, we found that murine bone marrow-derived dendritic cells responded to P. brasiliensis yeast cells infection by releasing IL-1β in a spleen tyrosine kinase (Syk), caspase-1 and NOD-like receptor (NLR) family member NLRP3 dependent manner. In addition, P. brasiliensis-induced NLRP3 inflammasome activation was dependent on potassium (K+) efflux, reactive oxygen species production, phagolysosomal acidification and cathepsin B release. Finally, using mice lacking the IL-1 receptor, we demonstrated...
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Research Interests: Immune response, Pattern Recognition, Dendritic Cells, Real-time RT-PCR, Signal Transduction, and 16 moreToll like receptor signaling, Biological Sciences, Mice, Adaptive Immunity, Protein Secretion, Animals, Male, Dendritic cell, Microarray Analysis, Physiological Stress Markers, Proteome, Paracoccidioides, Gene Expression Regulation, Gene expression profiling, Mannose receptor, and Differential expression
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Research Interests: Microbiology, Immunology, Kinetics, Medical Microbiology, Inflammation, and 16 moreInnate immunity, Apoptosis, Gene expression, Latin America, Microbes, Mice, Animals, Host Pathogen Interaction, Phagocytosis, Time Factors, Cdna Microarray, Membrane Protein, Paracoccidioides, Differential Gene Expression, Gene expression profiling, and Differential expression
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The thermodimorphic fungi Paracoccidioides brasiliensis and Paracoccidioides lutzii are the etiologic agents of Paracoccidioidomycosis (PCM), the most important endemic systemic mycosis in Latin America. Paracoccidioides grows as... more
The thermodimorphic fungi Paracoccidioides brasiliensis and Paracoccidioides lutzii are the etiologic agents of Paracoccidioidomycosis (PCM), the most important endemic systemic mycosis in Latin America. Paracoccidioides grows as saprophytic mycelia that produce infective conidia propagules, which are inhaled into the lungs where the fungus converts to the pathogenic yeast form. From the lungs, Paracoccidioides may disseminate through blood and lymphatics to several other organs and tissues. During the last decade we have witnessed the generation of a large amount of transcriptomic data regarding the events leading to the morphological transition and host niche adaptation. In this review we summarize those findings and discuss the consequence of gene expression plasticity in the persistence and survival of this pathogen. In addition, we discuss the future trends on the host-pathogen studies and how new molecular strategies, such as RNA-seq, dual RNA-seq and Chip-Seq can be powerful ...