Effects of mesoporous SiO2-CaO nanospheres on the murine peritoneal macrophages -- Candida albicans interface

TL;DR

This study investigates how hollow mesoporous SiO2-CaO nanospheres affect murine peritoneal macrophages' ability to phagocytize Candida albicans and their inflammatory response, finding no adverse effects on macrophage function and a temporary increase in fungal uptake.

Contribution

It provides new insights into the biocompatibility of mesoporous SiO2-CaO nanospheres with macrophages and their impact on antifungal activity and inflammation.

Findings

Nanospheres do not impair macrophage phagocytosis of Candida albicans.

Simultaneous nanosphere and fungus exposure reduces macrophage inflammatory markers.

Intracellular nanospheres temporarily increase fungal phagocytosis at low MOI.

Abstract

The use of nanoparticles for intracellular drug delivery could reduce the toxicity and side effects of the drug but, the uptake of these nanocarriers could induce adverse effects on cells and tissues after their incorporation. Macrophages play a central role in host defense and are responsible for in vivo nanoparticle trafficking. Assessment of their defense capacity against pathogenic micro-organisms after nanoparticle uptake, is necessary to prevent infections associated with nanoparticle therapies. In this study, the effects of hollow mesoporous SiO2-CaO nanospheres labeled with fluorescein isothiocyanate (FITC-NanoMBGs) on the function of peritoneal macrophages was assessed by measuring their ability to phagocytize Candida albicans expressing a red fluorescent protein. Two macrophage-fungus ratios (MOI 1 and MOI 5) were used and two experimental strategies were carried out: a) pretreatment of macrophages with FITC-NanoMBGs and subsequent fungal infection; b) competition assays after simultaneous addition of fungus and nanospheres. Macrophage pro-inflammatory phenotype markers (CD80 expression and interleukin 6 secretion) were also evaluated. Significant decreases of CD80+ macrophage percentage and interleukin 6 secretion were observed after 30 min, indicating that the simultaneous incorporation of NanoMBG and fungus favors the macrophage noninflammatory phenotype. The present study evidences that the uptake of these nanospheres in all the studied conditions does not alter the macrophage function. Moreover, intracellular FITCNanoMBGs induce a transitory increase of the fungal phagocytosis by macrophages at MOI 1 and after a short time of interaction. In the competition assays, as the intracellular fungus quantity increased, the intracellular FITC-NanoMBG content decreased in a MOI- and timedependent manner...