The anti-mitochondrial antifungal assay for the discovery and development of new drugs

INTRODUCTION

New targets and drugs are constantly searched for to effectively combat fungal infections and diseases such as cancer. Mitochondria, as the main powerhouses of eukaryotic cells, must be regarded as important targets for the development of new therapies. This has lead to the development of a fungal assay that shows potential in the selection of new antifungal and anticancer drugs as well as the identification of compounds that are toxic to human mitochondria.

AREAS COVERED

In this review the authors discuss the development of a potential method of drug discovery that targets mitochondrial function. The authors cover the application of new nanotechnology as well as fungal systematic research where the link between fungal fruiting structures, cell growth, increased mitochondrial activity and susceptibility to a variety of anti-mitochondrial drugs is assessed.

EXPERT OPINION

This assay shows potential to select anti-mitochondrial drugs as a first screen. This should be followed up by more specific in vitro and in vivo tests to pinpoint the type of anti-mitochondrial activity exerted by these drugs, if any. This is because the possibility exists that compounds regarded as anti-mitochondrial may not inhibit mitochondrial function but other fruiting structure developmental stages and therefore yield false positives. To enhance our knowledge on how these drugs act at the structural level, the authors recommend Nano Scanning Auger Microscopy as the tool of choice.

Anti-inflammatory drugs selectively target sporangium development in Mucor

It is known that acetylsalicylic acid, an anti-inflammatory and anti-mitochondrial drug, targets structure development and functions of yeasts depending on elevated levels of mitochondrial activity. Using antibody probes, we previously reported that sporangia of Mucor circinelloides also contain increased mitochondrial activity, yielding high levels of 3-hydroxyoxylipins. This was, however, not found in Mortierella alpina (subgenus Mortierella ). In this study we report that acetylsalicylic acid (aspirin) also targets sporangium development of Mucor circinelloides selectively, while hyphae with lower levels of mitochondrial activity are more resistant. Similar results were obtained when the anti-inflammatory compounds benzoic acid, ibuprofen, indomethacin, and salicylic acid were tested. The anti-inflammatory drugs exerted similar effects on this dimorphic fungus as found under oxygen-limited conditions. Interestingly, sporangium development of Mortierella alpina was found not to be selectively targeted by these drugs. Mortierella alpina, which could not exhibit dimorphic growth under oxygen-limited conditions, was also more sensitive to the anti-inflammatory drugs when compared with Mucor circinelloides. These results prompt further research to assess the applicability of these antimitochondrial antifungals to protect plants and animals against Mucor infections.