Nutritional Conditions Modulate C. neoformans Extracellular Vesicles’ Capacity to Elicit Host Immune Response

Abstract

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 dissemination of C. neoformans. Thus, these results highlight the versatility of EVs’ properties during infection by C. neoformans in different tissues and support ongoing efforts to harness EVs to prevent and treat cryptococcosis.

The development of extracellular vesicle markers for the fungal phytopathogen Colletotrichum higginsianum

“…Functionally, fungal EVs have been described as “virulence bags” containing multiple factors important for pathology (Albuquerque et al., 2008; Matos Baltazar et al., 2016; Rodrigues et al., 2007; Vallejo et al., 2012; Vargas et al., 2015). Injections of fungal EVs in mice have been shown to enhance the virulence of fungal pathogens and promote the colonization of organs (Huang et al., 2012; Ikeda et al., 2018; Marina et al., 2020). Through cell‐to‐cell communication, fungal EVs also promote biofilm formation, antibiotic resistance and heightened virulence states in recipient fungal cells (Hai et al., 2020; Zarnowski et al., 2018).…”

Pathogenicity and Growth Conditions Modulate Fonsecaea Extracellular Vesicles’ Ability to Interact With Macrophages

“…The influence of factors such as growth conditions, cell morphology, and fungal strains used in experiments appears to be important in the modulation of EVs biogenesis, size, cargo, and function, although how these factors affect fungal EVs production remains poorly understood ( Cleare et al., 2020 ; Marina et al., 2020 ; Rizzo et al., 2020a ). Since morphological transition and MC establishment during CBM is crucial for Fonsecaea survival and pathogenicity, understanding how nutritional conditions and growth factors interfere with EVs characteristics and host-cell communication might grant new insights regarding the roles of extracellular components produced by Fonsecaea spp.…”

“…Lipids and proteins are fundamental molecular components found in a vast array of fungal EVs that can be used as indicators of the levels of vesicles production ( Oliveira et al., 2010b ; Baltazar et al., 2018 ; Zhao et al., 2019 ; Cleare et al., 2020 ; Lavrin et al., 2020 ; Marina et al., 2020 ). In the present work, it was observed that Fonsecaea EVs isolated from the highly nutritional medium led to enhanced levels of ergosterol and protein content compared to EVs obtained from both MM conditions.…”

“…The aptness to generate highest amount of EVs might be because that F. erecta has initially been obtained from the environment and thus, has a predisposition to grow in conditions similar to experimental conditions. Nutritional availability of the culture medium has been shown to modulate the lipid and protein content of EVs produced by C. neoformans and H. capsulatum ( Cleare et al., 2020 ; Marina et al., 2020 ). EVs produced by C. neoformans in MM (Sabourad Dextrose Broth 50%) presented elevated levels of ergosterol/protein ratio when compared to the vesicles isolated from RM (Sabourad Dextrose Broth 100%) ( Marina et al., 2020 ).…”

Isolation and Characterization of Extracellular Vesicles from the Fungal PhytopathogenColletotrichum higginsianum

“…Functionally, fungal EVs have been described as "virulence bags" containing multiple factors important for pathology (Albuquerque et al, 2008;Matos Baltazar et al, 2016;Rodrigues et al, 2007;Vallejo et al, 2012;Vargas et al, 2015). Injections of fungal EVs in mice have been shown to enhance the virulence of fungal pathogens and promote the colonization of organs (Huang et al, 2012;Ikeda et al, 2018;Marina et al, 2020).…”