Human neutrophils produce extracellular traps against Paracoccidioides brasiliensis

Abstract

Neutrophils play an important role as effector cells and contribute to the resistance of the host against microbial pathogens. Neutrophils are able to produce extracellular traps (NETs) in response to medically important fungi, including Aspergillus spp., Candida albicans and Cryptococcus gattii. However, NET production in response to Paracoccidioides brasiliensis has yet to be studied. We have demonstrated that human neutrophils produce NETs against both conidia and yeasts of P. brasiliensis. Although the NADPH oxidase inhibitor diphenyleneiodonium chloride (DPI) did not alter NET production against conidia, it partially suppressed NET formation against P. brasiliensis yeasts. Cytochalasin D or IFN-c did not affect the production of NETs against the fungus. Additionally, a mutant strain of P. brasiliensis with reduced expression of an alternative oxidase induced significantly higher levels of NETs in comparison with the WT strain. Finally, c.f.u. quantification of P. brasiliensis showed no significant differences when neutrophils were treated with DPI, DNase I or cytochalasin D as compared with untreated cells. These data establish that NET formation by human neutrophils appears to be either dependent or independent of reactive oxygen species production, correlating with the fungal morphotype used for stimulation. However, this mechanism was ineffective in killing the fungus.

Participation of dectin-1 receptor on NETs release against Paracoccidioides brasiliensis: Role on extracellular killing

“…However, more prominent results in relation to involvement of both mechanisms were found when cells were activated with either GM-CSF, IFN-␥ or TNF-␣¸ a strategy to get significant increase in total fungicidal activity (Rodrigues et al, 2007). Contrasting with our results, Mejía et al (2015) in a recent study, showed that NETs are not involving in P. brasiliensis killing. These differences can be explained by the experimental design used.…”

“…High concentrations of these components in NETs, as well as their synergistic actions are responsible for the effective antimicrobial activity of these structures (Brinkmann and Zychlinsky, 2012). Recently, NETs release induced by P. brasiliensis was reported (Mejía et al, 2015;Della Coleta et al, 2015). Here, by using scanning electron microscopy we confirmed that P. brasiliensis virulent strain (P. brasiliensis 18) induces neutrophils to release NETs and that dectin-1 receptor is the main PRR involved in this process.…”

“…This process is significantly increased after cells activation with cytokines. According to Mejía et al (2015), ROS participate in NETs formation to P. brasiliensis in a dependence of fungus morphotype used as stimulus.…”

Macrophage Extracellular Traps: A Scoping Review

“…In the original NET description, cytochalasin D effectively prevented phagocytosis of Shigella flexneri or S. aureus but not NET release [5]. Other studies have also reported that cytoskeletal inhibitors had no effect on NET formation in response to Paracoccidioides brasiliensis or gold nanoparticles [49,50]. Neeli et al [51] reported that a 10 μM treatment with either the microtubule inhibitor nocodazole or cytochalasin D diminished histone deamination and NET release in response to LPS, and similar results were documented by Jerjomiceva et al [52] using enrofloxacin-treated bovine neutrophils.…”

Challenges and Strategies for Proteome Analysis of the Interaction of Human Pathogenic Fungi with Host Immune Cells

“…Further fungicidal effects have been reported for both yeast and hyphal forms of C. albicans [120]. NETosis has also been observed in response to Cryptococcus neoformans [121] and Paracoccidioides brasiliensis [122]. …”