An Intracellular Arrangement of Histoplasma capsulatum Yeast-Aggregates Generates Nuclear Damage to the Cultured Murine Alveolar Macrophages

Pitangui, Nayla de Souza; Sardi, Janaína de Cássia Orlandi; Voltan, Aline Raquel; Santos, Catarina; Silva, Julhiany de Fátima da; Silva, Rosangela A. M. da; Souza, Felipe O.; Soares, Christiane Pienna; Rodríguez-Arellanes, Gabriela; Taylor, Mária Lucía; Mendes-Giannini, María José Soares; Fusco‐Almeida, Ana Marisa

doi:10.3389/fmicb.2015.01526

Cited by 14 publications

(12 citation statements)

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“…Fungal biofilms are sessile communities of microorganisms, which cells adhere to each other and to biotic or abiotic substrate, usually surrounded by an extracellular matrix of polysaccharides ( Costa-Orlandi et al, 2017 ). Biofilm cells have structural, functional, and genetic differences in relation to planktonic cells ( Kuhn and Ghannoum, 2004 ; Mowat et al, 2007 ; Ramage et al, 2009 ; Pitangui et al, 2012 , 2016 ). The biofilm morphology can be influenced by the quality and quantity of available nutrients, such as the composition of the culture medium ( Kucharíkova et al, 2011 ; Lee et al, 2013 ; Serrano-Fujarte et al, 2015 ) and the oxygen concentration ( Stichternoth and Ernst, 2009 ; Bonhomme et al, 2011 ).…”

Section: Introductionmentioning

confidence: 99%

Biofilm Formation by Histoplasma capsulatum in Different Culture Media and Oxygen Atmospheres

et al. 2020

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Histoplasma capsulatum is a dimorphic fungus that causes an important systemic mycosis called histoplasmosis. It is an infectious disease with high prevalence and morbidity that affects the general population. Recently, the ability of these fungi to form biofilms, a phenotype that can induce resistance and enhance virulence, has been described. Despite some efforts, data regarding the impact of nutrients and culture media that affect the H. capsulatum biofilm development in vitro are not yet available. This work aimed to study H. capsulatum biofilms, by checking the influence of different culture media and oxygen atmospheres in the development of these communities. The biofilm formation by two strains (EH-315 and G186A) was characterized under different culture media: [Brain and Heart Infusion (BHI), Roswell Park Memorial Institute (RPMI) with 2% glucose, Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with 10% fetal bovine serum and nutrient medium HAM-F12 (HAM-F12) supplemented with glucose (18.2 g/L), glutamic acid (1 g/L), HEPES (6 g/L) and L-cysteine (8.4 mg/L)] and oxygen atmospheres (aerobiosis and microaerophilia), using the XTT reduction assay to quantify metabolic activities, crystal violet staining for biomass, safranin staining for the quantification of polysaccharide material and scanning electron microscopy (SEM) for the observation of topographies. Results indicated that although all culture mediums have stimulated the maturation of the communities, HAM-F12 provided the best development of biomass and polysaccharide material when compared to others. Regarding the oxygen atmospheres, both stimulated an excellent development of the communities, however in low oxygen conditions an exuberant amount of extracellular matrix was observed when compared to biofilms formed in aerobiosis, mainly in the HAM-F12 media. SEM images showed yeasts embedded by an extracellular matrix in several points, corroborating the colorimetric assays. However, biofilms formed in BHI, RPMI, and DMEM significantly induced yeast to hyphae reversal, requiring further investigation. The results obtained so far contribute to in vitro study of biofilms formed by these fungi and show that nutrition promoted by different media modifies the development of these communities. These data represent advances in the field of biofilms and contribute to future studies that can prove the role of these communities in the fungi-host interaction.

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Section: Introductionmentioning

confidence: 99%

Biofilm Formation by Histoplasma capsulatum in Different Culture Media and Oxygen Atmospheres

et al. 2020

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“…In vitro studies have reported that cultured alveolar macrophages are apoptotic within 24 h after incubation with Histoplasma at a multiplicity of five yeasts per cell, and this is suggested to be due to the expression of calcium binding protein (CBP), a yeast-specific secreted effector (38,39). Pitangui et al examined the interaction of Histoplasma with AMJ2-C11 alveolar macrophages and found that apoptosis occurs within 5 h after incubation with a 5:1 ratio of yeasts to cells (40). In that study, the authors noted that microscopic imaging revealed that individual cells contain up to 24 to 30 yeasts, and thus, it is not surprising that apoptosis occurs rapidly in that scenario (40).…”

Section: Discussionmentioning

confidence: 99%

“…Pitangui et al examined the interaction of Histoplasma with AMJ2-C11 alveolar macrophages and found that apoptosis occurs within 5 h after incubation with a 5:1 ratio of yeasts to cells ( 40 ). In that study, the authors noted that microscopic imaging revealed that individual cells contain up to 24 to 30 yeasts, and thus, it is not surprising that apoptosis occurs rapidly in that scenario ( 40 ). Indeed, the multiplicity of infection has been directly correlated with cell death after in vitro infection ( 41 ).…”

Section: Discussionmentioning

confidence: 99%

Biodiverse Histoplasma Species Elicit Distinct Patterns of Pulmonary Inflammation following Sublethal Infection

Jones

Sepúlveda

Goldman

2020

mSphere

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Histoplasma is an endemic dimorphic fungus that can cause disease in healthy and immunocompromised individuals after the transition of inhaled spores into the facultative intracellular yeast form. There is substantial diversity among Histoplasma species, but it is not clear how this heterogeneity impacts the progression of pathology and cellular immune responses during acute respiratory infection, which represents the vast majority of histoplasmosis disease burden. After inoculating mice intranasally with a sublethal inoculum, we characterized the immune response to Histoplasma capsulatum (strain G186A) and Histoplasma ohiense (strain G217B) using comprehensive flow cytometric and single-cell analyses. Within 8 days after inoculation, H. ohiense induced a significantly higher infiltration of neutrophils and inflammatory monocytes into the lung compared to H. capsulatum. Microscopic analysis of infected lung tissue revealed that although the total number of fungi was similar within inflamed lung lesions, we observed different species-dependent intracellular yeast distribution patterns. Inoculation with gfp-expressing strains indicated that H. ohiense, but not H. capsulatum, was associated primarily with alveolar macrophages early after infection. Interestingly, we observed a significant reduction in the total number of alveolar macrophages 12 to 16 days after H. ohiense, but not H. capsulatum infection, despite similar intracellular growth dynamics within AMJ2-C11 alveolar macrophages in vitro. Together, our data suggest that H. ohiense, but not H. capsulatum, preferentially interacts with alveolar macrophages early after infection, which may lead to a different course of inflammation and resolution despite similar rates of fungal clearance. IMPORTANCE Acute pulmonary histoplasmosis in healthy individuals comprises most of the disease burden caused by the fungal pathogen Histoplasma. Fungal pneumonia is frequently delayed in diagnosis and treatment due to a prolonged period of quiescence early during infection. In this study, we used a murine respiratory model of histoplasmosis to investigate how different Histoplasma species modulate lung inflammation throughout the complete course of infection. We propose that a relatively low, sublethal inoculum is ideal to model acute pulmonary histoplasmosis in humans, primarily due to the quiescent stage of fungal growth that occurs in the lungs of mice prior to the initiation of inflammation. Our results reveal the unique course of lung immunity associated with divergent species of Histoplasma and imply that the progression of clinical disease is considerably more heterogeneous than previously recognized.

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“…Growth in a mass increases the resistance of the organisms to environmental stress, their resistance to antifungal activities and also effectively shields them from attack by phagocytes (Williams and Ramage, 2015). Fungi that are capable of forming biofilms are C. albicans (Zelante et al, 2012), C. neoformans, H. casulatum, P. brasiliensis , and A. fumigatus (Ramage et al, 2009; Pitangui et al, 2015; Sardi et al, 2015). …”

Section: Stealthmentioning

confidence: 99%

Anti-Immune Strategies of Pathogenic Fungi

Marcos¹,

Oliveira²,

Melo³

et al. 2016

Front. Cell. Infect. Microbiol.

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Pathogenic fungi have developed many strategies to evade the host immune system. Multiple escape mechanisms appear to function together to inhibit attack by the various stages of both the adaptive and the innate immune response. Thus, after entering the host, such pathogens fight to overcome the immune system to allow their survival, colonization and spread to different sites of infection. Consequently, the establishment of a successful infectious process is closely related to the ability of the pathogen to modulate attack by the immune system. Most strategies employed to subvert or exploit the immune system are shared among different species of fungi. In this review, we summarize the main strategies employed for immune evasion by some of the major pathogenic fungi.

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An Intracellular Arrangement of Histoplasma capsulatum Yeast-Aggregates Generates Nuclear Damage to the Cultured Murine Alveolar Macrophages

Cited by 14 publications

References 40 publications

Biofilm Formation by Histoplasma capsulatum in Different Culture Media and Oxygen Atmospheres

Biofilm Formation by Histoplasma capsulatum in Different Culture Media and Oxygen Atmospheres

Biodiverse Histoplasma Species Elicit Distinct Patterns of Pulmonary Inflammation following Sublethal Infection

Anti-Immune Strategies of Pathogenic Fungi

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