Objectives:

Aspergillus fumigatus is the most important airborne fungal pathogen that infects immunocompromised patients. Several virulence factors are present in this fungus, which, in particular allow its conidia to survive inside macrophages. A combination of caspofungin and humidimycin has been proposed as a new potential drug combination against aspergillosis. Humidimycin prevents the caspofungin paradoxical effect by inhibiting the salvage pathway enabling A. fumigatus to resist a high dose of caspofungin. 


Methods:

We generated polymer based nanoparticles with a size range from 200 to 800 nm. Our main target are conidia residing in macrophages, therefore we decorated the nanoparticles with mannose moieties. The mannose facilitates the nanoparticles entering cells by mannose receptor-mediated endocytosis. The macrophage cell line RAW 264.7 was treated with a variety of nanoparticle formulations and confocal laser scanning microscopy was performed to monitor endocytosis. The uptake mechanism was determined by inhibition of different endocytic pathways and immunofluorescence. Additionally, the cytotoxicity of the nanoparticles was tested by resazurin assay.



Results:

Preliminary results showed an uptake of mannose-functionalized nanoparticles containing Nile Red as cargo. Also, it was observed how nanoparticles containing Nile Red co-localized at the conidium-phagolysosome compartment.



Conclusion:

By investigating the efficacy of nanoparticles containing antifungal drugs we aim to develop improved treatment options to fight A. fumigatus conidia inside macrophages.

Prodrug nanoparticles as treatment for Aspergillus fumigatus conidia residing in macrophages