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Journal of Fungi (Basel, Switzerland) Nov 2023Members of the complex are the causative agents of Paracoccidioidomycosis (PCM), a human systemic mycosis endemic in Latin America. Upon initial contact with the host,...
Members of the complex are the causative agents of Paracoccidioidomycosis (PCM), a human systemic mycosis endemic in Latin America. Upon initial contact with the host, the pathogen needs to uptake micronutrients. Nitrogen is an essential source for biosynthetic pathways. Adaptation to nutritional stress is a key feature of fungi in host tissues. Fungi utilize nitrogen sources through Nitrogen Catabolite Repression (NCR). NCR ensures the scavenging, uptake and catabolism of alternative nitrogen sources, when preferential ones, such as glutamine or ammonium, are unavailable. The NanoUPLC-MS proteomic approach was used to investigate the NCR response of after growth on proline or glutamine as a nitrogen source. A total of 338 differentially expressed proteins were identified. demonstrated that gluconeogenesis, β-oxidation, glyoxylate cycle, adhesin-like proteins, stress response and cell wall remodeling were triggered in NCR-proline conditions. In addition, within macrophages, yeast cells trained under NCR-proline conditions showed an increased ability to survive. In general, this study allows a comprehensive understanding of the NCR response employed by the fungus to overcome nutritional starvation, which in the human host is represented by nutritional immunity. In turn, the pathogen requires rapid adaptation to the changing microenvironment induced by macrophages to achieve successful infection.
PubMed: 37998907
DOI: 10.3390/jof9111102 -
Journal of Fungi (Basel, Switzerland) Nov 2023The fungal pathogen causes systemic mycosis Paracoccidioidomycosis (PCM), which presents a broad distribution in Latin America. Upon infection, the fungus undergoes a...
The fungal pathogen causes systemic mycosis Paracoccidioidomycosis (PCM), which presents a broad distribution in Latin America. Upon infection, the fungus undergoes a morphological transition to yeast cells and provokes an inflammatory granulomatous reaction with a high number of neutrophils in the lungs. In this work, we employed proteomic analysis to investigate the in vitro response of the fungus to the interaction with human neutrophils. Proteomic profiling of yeast cells harvested at 2 and 4 h post interaction with human polymorphonuclear cells allowed the identification of 505 proteins differentially accumulated. The data indicated that yeast cells underwent a shift in metabolism from glycolysis to Beta oxidation, increasing enzymes of the glyoxylate cycle and upregulating enzymes related to the detoxification of oxidative and heat shock stress. To our knowledge, this is the first study employing proteomic analysis in the investigation of the response of a member of the genus to the interaction with neutrophils.
PubMed: 37998893
DOI: 10.3390/jof9111088 -
Dectin-2 is critical for phagocyte function and resistance to Paracoccidioides brasiliensis in mice.Medical Mycology Nov 2023Germline-encoded pattern recognition receptors, particularly C-type lectin receptors (CLRs), are essential for phagocytes to sense invading fungal cells. Among CLRs,...
Germline-encoded pattern recognition receptors, particularly C-type lectin receptors (CLRs), are essential for phagocytes to sense invading fungal cells. Among CLRs, Dectin-2 (encoded by Clec4n) plays a critical role in the antifungal immune response as it recognizes high-mannose polysaccharides on the fungal cell wall, triggering phagocyte functional activities and ultimately determining adaptive responses. Here, we assessed the role of Dectin-2 on the course of primary Paracoccidioides brasiliensis systemic infection in mice with Dectin-2-targeted deletion. Paracoccidioides brasiliensis constitutes the principal etiologic agent of paracoccidioidomycosis, the most prominent invasive mycosis in Latin American countries. The deficiency of Dectin-2 resulted in shortened survival rates, high lung fungal burden, and increased lung pathology in mice infected with P. brasiliensis. Consistently, dendritic cells (DCs) from mice lacking Dectin-2 infected ex vivo with P. brasiliensis showed impaired secretion of several proinflammatory and regulatory cytokines, including TNF-α, IL-1β, IL-6, and IL-10. Additionally, when cocultured with splenic lymphocytes, DCs were less efficient in promoting a type 1 cytokine pattern secretion (i.e., IFN-γ). In macrophages, Dectin-2-mediated signaling was required to ensure phagocytosis and fungicidal activity associated with nitric oxide production. Overall, Dectin-2-mediated signaling is critical to promote host protection against P. brasiliensis infection, and its exploitation might lead to the development of new vaccines and immunotherapeutic approaches.
Topics: Mice; Animals; Paracoccidioides; Phagocytes; Lectins, C-Type; Macrophages; Paracoccidioidomycosis
PubMed: 37960963
DOI: 10.1093/mmy/myad117 -
Microorganisms Sep 2023Paracoccidioidomycosis ceti (PCM-C) is a chronic granulomatous keloidal dermatitis in cetaceans that has been reported worldwide and is caused by . Serological...
Paracoccidioidomycosis ceti (PCM-C) is a chronic granulomatous keloidal dermatitis in cetaceans that has been reported worldwide and is caused by . Serological cross-reactions among highly pathogenic fungal infections and related diseases have been reported. However, the true cross-reaction of antibodies against has remained unknown due to the use of positive control sera from infected dolphins. This study aimed to re-evaluate antibodies from mechanically dislodged fungal cells in the infected tissue of a PCM-C case and demonstrate the actual cross-reaction. The results revealed a limited cross-reaction between PCM-C and paracoccidioidomycosis, while the antibodies did not react with other pathogens such as , , and . Thus, the method for evaluation of the antibody against PCM-C is reliable, and there is potential for epidemiological study.
PubMed: 37894086
DOI: 10.3390/microorganisms11102428 -
Journal of Fungi (Basel, Switzerland) Sep 2023Considering the toxicity of conventional therapeutic approaches and the importance of precise mechanistic targets, it is important to explore signaling pathways...
Considering the toxicity of conventional therapeutic approaches and the importance of precise mechanistic targets, it is important to explore signaling pathways implicated in fungal pathobiology. Moreover, treatment of paracoccidioidomycosis, a systemic mycosis caused by a dimorphic fungus, requires prolonged therapeutic regimens. Among the numerous factors underpinning the establishment of spp. infection, the capacity to transition from the mycelial to the yeast form is of pivotal importance. The Drk1 protein of likely plays a decisive role in this morphological shift and subsequent virulence. We identified peptides with affinity for the PbDrk1 protein using the phage-display method and assessed the effects of these peptides on . The peptides were found to inhibit the phase transition of Furthermore, a substantial proportion of these peptides prevented adhesion to pneumocytes. Although these peptides may not possess inherent antifungal properties, they can augment the effects of certain antifungal agents. Notably, the cell wall architecture of appears to be modulated by peptide intervention, resulting in a reduced abundance of glycosylated proteins and lipids. These peptides were also evaluated for their efficacy in a model and shown to contribute to enhanced larval survival rates. The role of PbDrk1, which is notably absent in mammals, should be further investigated to improve the understanding of its functional role in , which may be helpful for designing novel therapeutic modalities.
PubMed: 37888236
DOI: 10.3390/jof9100980 -
Frontiers in Cellular and Infection... 2023Granulomas are important immunological structures in the host defense against the fungus , the main etiologic agent of Paracoccidioidomycosis (PCM), a granulomatous...
Granulomas are important immunological structures in the host defense against the fungus , the main etiologic agent of Paracoccidioidomycosis (PCM), a granulomatous systemic mycosis endemic in Latin America. We have performed transcriptional and proteomic studies of yeasts present in the pulmonary granulomas of PCM aiming to identify relevant genes and proteins that act under stressing conditions. C57BL/6 mice were infected with 1x10 yeasts and after 8- and 12-weeks of infection, granulomatous lesions were obtained for extraction of fungal and murine RNAs and fungal proteins. Dual transcriptional profiling was done comparing lung cells and yeasts from granulomas with uninfected lung cells and the original yeast suspension used in the infection, respectively. Mouse transcripts indicated a lung malfunction, with low expression of genes related to muscle contraction and organization. In addition, an increased expression of transcripts related to the activity of neutrophils, eosinophils, macrophages, lymphocytes as well as an elevated expression of IL-1β, TNF-α, IFN-γ, IL-17 transcripts were observed. The increased expression of transcripts for CTLA-4, PD-1 and arginase-1, provided evidence of immune regulatory mechanisms within the granulomatous lesions. Also, our results indicate iron as a key element for the granuloma to function, where a high number of transcripts related to fungal siderophores for iron uptake was observed, a mechanism of fungal virulence not previously described in granulomas. Furthermore, transcriptomics and proteomics analyzes indicated a low fungal activity within the granuloma, as demonstrated by the decreased expression of genes and proteins related to energy metabolism and cell cycle.
Topics: Animals; Mice; Paracoccidioides; Proteomics; Mice, Inbred C57BL; Paracoccidioidomycosis; Iron; Immunity; Granuloma
PubMed: 37868350
DOI: 10.3389/fcimb.2023.1268959 -
Mycoses Jan 2024Paracoccidioidomycosis is the most prevalent systemic mycosis in Latin America, with a high incidence in Brazil, Colombia and Venezuela, and constitutes a serious public...
BACKGROUND
Paracoccidioidomycosis is the most prevalent systemic mycosis in Latin America, with a high incidence in Brazil, Colombia and Venezuela, and constitutes a serious public health problem, a frequent cause of morbidity and disability for work. Some mechanisms of cell death are described as important tools in infectious processes. When apoptosis is blocked, RIPK (Receptor-interacting protein kinase) 3 dependent, a caspase-independent form of cell death, can limit the replication and spread of pathogens. Some molecules that mediate necroptosis include RIPK3 and have been extensively studied due to their signalling mechanism and pathological function. RIPK3 activates NLRP1 and NLRP3-mediated inflammasome formation. Caspase-1 has an important role in processing the cytokines ILβ and IL18 to their active form. Such molecules are part of the inflammasome characterization, whose caspase-1-dependent activation promotes the death of pyroptotic cells and the secretion of proinflammatory cytokines. Knowledge about the mechanisms of pathogen-mediated cell death can be useful for understanding of the pathogenesis of infections and inflammatory conditions.
OBJECTIVE
The objective of this work was to identify the mechanisms of programmed cell death and inflammasome components in human oral mucosal lesions of paracoccidioidomycosis through immunohistochemical methods and identification of RIPK-3, IL1β, IL18, NLRP-1 and caspase-1. Thirty specimens were included, and a histopathological analysis of the lesions was performed using haematoxylin-eosin staining.
RESULTS
Our results on in situ expression of inflammasome elements and programmed cell death showed increased expression of IL-1β, NLRP-1, caspase-1 and RIPK-3. We suggest that inflammasome complex participate in the immunopathogenesis in paracoccidioidomycosis oral lesions in an interplay with RIPK3.
Topics: Humans; Inflammasomes; Interleukin-18; Paracoccidioidomycosis; Apoptosis; Caspase 1; Cytokines
PubMed: 37837228
DOI: 10.1111/myc.13662 -
Radiologia Brasileira 2023To describe the clinical and radiological evolution of lesions during and after treatment in patients diagnosed with neuroparacoccidioidomycosis (NPCM).
OBJECTIVE
To describe the clinical and radiological evolution of lesions during and after treatment in patients diagnosed with neuroparacoccidioidomycosis (NPCM).
MATERIALS AND METHODS
This was a retrospective study of the medical records, computed tomography scans, and magnetic resonance imaging (MRI) scans of patients with NPCM treated between September 2013 and January 2022.
RESULTS
Of 36 cases of NPCM, eight were included in the study. One patient presented only with pachymeningeal and skull involvement, and seven presented with pseudotumors in the brain. Collectively, the eight patients presented with 52 lesions, of which 46 (88.5%) were supratentorial. There were 32 lesions with a diameter ≤ 1.2 cm, of which 27 (84.4%) disappeared during the treatment. In three cases, there were lesions > 1.2 cm that showed a characteristic pattern of evolution on MRI: an eccentric gadolinium contrast-enhanced nodule, with a subsequent decreased in the size and degree of contrast enhancement of the lesions.
CONCLUSION
In NPCM, supratentorial lesions seem to predominate. Lesions ≤ 1.2 cm tend to disappear completely during treatment. Lesions > 1.2 cm tend to present with a similar pattern, designated the "Star of Bethlehem sign", throughout treatment.
PubMed: 37829584
DOI: 10.1590/0100-3984.2023.0030 -
Radiologia Brasileira 2023
PubMed: 37829582
DOI: 10.1590/0100-3984.2023.56.4e4-en -
Revista Da Sociedade Brasileira de... 2023
Topics: Humans; Paracoccidioidomycosis; Constriction, Pathologic
PubMed: 37792840
DOI: 10.1590/0037-8682-0343-2023