Proteomic identification of metabolic changes in Paracoccidioides brasiliensis induced by a nitroheteroarylchalcone

Aim: To access the metabolic changes caused by a chalcone derivative (LabMol-75) through a proteomic approach. Methods: Proteomic analysis was performed after 9 h of Paracoccidioides brasiliensis yeast (Pb18) cell incubation with the LabMol-75 at MIC. The proteomic findings were validated through in vitro and in silico assays. Results: Exposure to the compound led to the downregulation of proteins associated with glycolysis and gluconeogenesis, β-oxidation, the citrate cycle and the electron transport chain. Conclusion: LabMol-75 caused an energetic imbalance in the fungus metabolism and deep oxidative stress. Additionally, the in silico molecular docking approach pointed to this molecule as a putative competitive inhibitor of DHPS.

Proteomic alterations in Paracoccidioides brasiliensis caused by exposure to curcumin

Paracoccidioides spp. are the etiological agent of paracoccidioidomycosis, a disease that causes skin lesions and affect the lungs and other organs. The current management of the disease is long and has several side effects that often lead the patient to give up the treatment, sequelae and even death. The search for new forms of treatment that minimize these drawbacks is very important. Thus, natural compounds are targets of great interest. Curcumin is one of the main components of the tubers of Curcuma longa, presenting medicinal effects well described in the literature, including the antifungal effect on Paracocidioides brasiliensis. Nevertheless, the mechanisms related to the antifungal effect of such compound are still unknown, so the objective of the present research is to understand what changes occur in the metabolism of P. brasiliensis after exposure to curcumin and to identify the main targets of the compound. Proteomic analysis as based on nanoUPLC-MS analysis and the functional classification of the identified proteins. The main metabolic processes that were being regulated were biologically validated through assays such as fluorescence microscopy, EPR and phagocytosis. Proteomic analysis revealed that curcumin regulates several metabolic processes of the fungus, including important pathways for energy production, such as the glycolytic pathway, beta oxidation and the glyoxylate cycle. Protein synthesis was down-regulated in fungi exposed to curcumin. The electron transport chain and the tricarboxylic acid cycle were also down-regulated, indicating that both the mitochondrial membrane and the mitochondrial activity were compromised. Plasma membrane and cell wall structure were altered following exposure to the compound. The fungus' ability to survive the phagocytosis process by alveolar macrophages was reduced. Thus, curcumin interferes with several metabolic pathways in the fungus that causes paracoccidioidomycosis. BIOLOGICAL SIGNIFICANCE: The challenges presented by the current treatment of paracoccidioidomycosis often contributing to patients' withdrawal from treatment, leading to sequelae or even death. Thus, the search for new treatment options against this disease is growing. The discovery that curcumin is active against Paracoccidioides was previously reported by our study group. Here, we clarify how the compound acts on the fungus causing its growth inhibition and decreased viability. Understanding the mechanisms of action of curcumin on P. brasiliensis elucidates how we can seek new alternatives and which metabolic pathways and molecular targets we should focus on in this incessant search to bring the patient a treatment with fewer adverse effects.

Challenges in Serologic Diagnostics of Neglected Human Systemic Mycoses: An Overview on Characterization of New Targets

Systemic mycoses have been viewed as neglected diseases and they are responsible for deaths and disabilities around the world. Rapid, low-cost, simple, highly-specific and sensitive diagnostic tests are critical components of patient care, disease control and active surveillance. However, the diagnosis of fungal infections represents a great challenge because of the decline in the expertise needed for identifying fungi, and a reduced number of instruments and assays specific to fungal identification. Unfortunately, time of diagnosis is one of the most important risk factors for mortality rates from many of the systemic mycoses. In addition, phenotypic and biochemical identification methods are often time-consuming, which has created an increasing demand for new methods of fungal identification. In this review, we discuss the current context of the diagnosis of the main systemic mycoses and propose alternative approaches for the identification of new targets for fungal pathogens, which can help in the development of new diagnostic tests.

The role of Cryptococcus neoformans histone deacetylase genes in the response to antifungal drugs, epigenetic modulators and to photodynamic therapy mediated by an aluminium phthalocyanine chloride nanoemulsion in vitro

Cryptococcus is a globally distributed fungal pathogen that primarily afflicts immunocompromised individuals. The therapeutic options are limited and include mostly amphotericin B or fluconazole, alone or in combination. The extensive usage of antifungals allowed the selection of resistant pathogens posing threats to global public health. Histone deacetylase genes are involved in Cryptococcus virulence, and in pathogenicity and resistance to azoles in Candida albicans. Aiming to assess whether histone deacetylase genes are involved in antifungal response and in synergistic drug interactions, we evaluated the activity of amphotericin B, fluconazole, sulfamethoxazole, sodium butyrate or trichostatin A (histone deacetylase inhibitors), and hydralazine or 5- aza-2'-deoxycytidine (DNA methyl-transferase inhibitors) against different Cryptococcus neoformans strains, C. neoformans histone deacetylase null mutants and Cryptococcus gattii NIH198. The drugs were employed alone or in different combinations. Fungal growth after photodynamic therapy mediated by an aluminium phthalocyanine chloride nanoemulsion, alone or in combination with the aforementioned drugs, was assessed for the C. neoformans HDAC null mutant strains. Our results showed that fluconazole was synergistic with sodium butyrate or with trichostatin A for the hda1Δ/hos2Δ double mutant strain. Sulfamethoxazole was synergistic with sodium butyrate or with hydralazine also for hda1Δ/hos2Δ. These results clearly indicate a link between HDAC impairment and drug sensitivity. Photodynamic therapy efficacy on controlling the growth of the HDAC mutant strains was increased by amphotericin B, fluconazole, sodium butyrate or hydralazine. This is the first study in Cryptococcus highlighting the combined effects of antifungal drugs, histone deacetylase or DNA methyltransferase inhibitors and photodynamic therapy in vitro.

Interaction with Pantoea agglomerans Modulates Growth and Melanization of Sporothrix brasiliensis and Sporothrix schenckii

Sporothrix brasiliensis and Sporothrix schenckii stand as the most virulent agents of sporotrichosis, a worldwide-distributed subcutaneous mycosis. The origin of Sporothrix virulence seems to be associated with fungal interactions with organisms living in the same environment. To assess this hypothesis, the growth of these two species in association with Pantoea agglomerans, a bacterium with a habitat similar to Sporothrix spp., was evaluated. Growth, melanization, and gene expression of the fungus were compared in the presence or absence of the bacterium in the same culture medium. Both S. brasiliensis and S. schenckii grew in contact with P. agglomerans yielding heavily melanized conidia after 5 days of incubation at 30 °C in Sabouraud agar. This increased melanin production occurred around bacterial colonies, suggesting that fungal melanization is triggered by a diffusible bacterial product, which is also supported by a similar pattern of melanin production during Sporothrix spp. growth in contact with heat-killed P. agglomerans. Growth of P. agglomerans was similar in the presence or absence of the fungus. However, the growth of S. brasiliensis and S. schenckii was initially inhibited, but further enhanced when these species were co-cultured with P. agglomerans. Moreover, fungi were able to use killed bacteria as both carbon and nitrogen sources for growth. Representational difference analysis identified overexpressed genes related to membrane transport when S. brasiliensis was co-cultured with the bacteria. The down-regulation of metabolism-related genes appears to be related to nutrient availability during bacterial exploitation. These findings can lead to a better knowledge on Sporothrix ecology and virulence.

Argentilactone Molecular Targets in Paracoccidioides brasiliensis Identified by Chemoproteomics

Paracoccidioidomycosis (PCM) is the cause of many deaths from systemic mycoses. The etiological agents of PCM belong to the Paracoccidioides genus, which is restricted to Latin America. The infection is acquired through the inhalation of conidia that primarily lodge in the lungs and may disseminate to other organs and tissues. The treatment for PCM is commonly performed via the administration of antifungals such as amphotericin B, co-trimoxazole, and itraconazole. The antifungal toxicity and side effects, in addition to their long treatment times, have stimulated research for new bioactive compounds. Argentilactone is a compound that was isolated from the Brazilian savanna plant Hyptis ovalifolia, and it has been suggested to be a potent antifungal, inhibiting the dimorphism of P. brasiliensis and the enzymatic activity of isocitrate lyase, a key enzyme of the glyoxylate cycle. This work was developed due to the importance of elucidating the putative mode of action of argentilactone. The chemoproteomics approach via affinity chromatography was the methodology used to explore the interactions between P. brasiliensis proteins and argentilactone. A total of 109 proteins were identified and classified functionally. The most representative functional categories were related to amino acid metabolism, energy, and detoxification. Argentilactone inhibited the enzymatic activity of malate dehydrogenase, citrate synthase, and pyruvate dehydrogenase. Furthermore, argentilactone induces the production of reactive oxygen species and inhibits the biosynthesis of cell wall polymers.

Brazilian guidelines for the clinical management of paracoccidioidomycosis

Paracoccidioidomycosis is a systemic fungal disease occurring in Latin America that is associated with rural environments and agricultural activities. However, the incidence and prevalence of paracoccidiodomycosis is underestimated because of the lack of compulsory notification. If paracoccidiodomycosis is not diagnosed and treated early and adequately, the endemic fungal infection could result in serious sequelae. While the Paracoccidioides brasiliensis ( P. brasiliensis ) complex has been known to be the causal agent of paracoccidiodomycosis, a new species, Paracoccidioides lutzii ( P. lutzii ), has been reported in Rondônia, where the disease has reached epidemic levels, and in the Central West and Pará. Accurate diagnoses and availability of antigens that are reactive with the patients' sera remain significant challenges. Therefore, the present guidelines aims to update the first Brazilian consensus on paracoccidioidomycosis by providing evidence-based recommendations for bedside patient management. This consensus summarizes etiological, ecoepidemiological, molecular epidemiological, and immunopathological data, with emphasis on clinical, microbiological, and serological diagnosis and management of clinical forms and sequelae, as well as in patients with comorbidities and immunosuppression. The consensus also includes discussion of outpatient treatments, severe disease forms, disease prevalence among special populations and resource-poor settings, a brief review of prevention and control measures, current challenges and recommendations.

TLR 9 involvement in early protection induced by immunization with rPb27 against Paracoccidioidomycosis

Paracoccidioidomycosis is caused by fungi of the Paracoccidioides genus and constitutes the most prevalent deep mycosis in Latin America. Toll-like receptors promote immune response against infectious agents. Recently, it was reported that TLR9 is crucial for mice survival during the first 48 h of P. brasiliensis infection. In this study, we used CPG oligodeoxynucleotide motif as an adjuvant with and without rPb27 to immunize mice against Paracoccidioidomycosis. CPG adjuvant induced differential recruitment of lymphocytes in the inflammatory process and a lower recruitment of neutrophils. In addition, CPG induced the production of pro-inflammatory cytokines such as IL-1β, TNF-α, IL-6 and IL-12; increased phagocytic ability and microbicidal activity by macrophages; and induced differential production of lgG2a and lgG2b, subtypes of Ig. Knockout mice for TLR9 and IL-12 showed higher fungal loads and rates of mortality compared to control mice after 30 days of infection. The association between CPG and rPb27 induced a high level of protection against Paracoccidioidomycosis after the first 30 days of infection but not at 60 days. Our findings demonstrate that TLR 9 plays a role in the protection induced by immunization with rPb27 and confirms the importance of TLR9 in the initial protection against Paracoccidioidomycosis.