Cellular Cytotoxicity and Oxidative Potential of Recurrent Molds of the Genus Aspergillus Series Versicolores.

Antoine Géry,Charlie Lepetit,Natacha Heutte,Julie Bonhomme,Virginie Séguin,David Garon

doi:10.3390/microorganisms10020228

Abstract

Molds are ubiquitous biological pollutants in bioaerosols. Among these molds, the genus Aspergillus is found in the majority of indoor air samples, and includes several species with pathogenic and toxigenic properties. Aspergillus species in the series Versicolores remain little known despite recurrence in bioaerosols. In order to investigate their toxicity, we studied 22 isolates of clinical and environmental origin, corresponding to seven different species of the series Versicolores. Spore suspensions and ethyl acetate extracts prepared from fungal isolates were subjected to oxidative potential measurement using the dithiothreitol (DTT) test and cell survival measurement. The DTT tests showed that all species of the series Versicolores had an oxidative potential, either by their spores (especially for Aspergillus jensenii) or by the extracts (especially from Aspergillus amoenus). Measurements of cell survival of A549 and HaCaT cell lines showed that only the spore suspension containing 105 spores/mL of Aspergillus jensenii caused a significant decrease in survival after 72 h of exposure. The same tests performed with mixtures of 105 spores/mL showed a potentiation of the cytotoxic effect, with a significant decrease in cell survival for mixtures containing spores of two species (on A549 cells, p = 0.05 and HaCaT cells, p = 0.001) or three different species (on HaCaT cells, p = 0.05). Cell survival assays after 72 h of exposure to the fungal extracts showed that Aspergillus puulaauensis extract was the most cytotoxic (IC50 < 25 µg/mL), while Aspergillus fructus caused no significant decrease in cell survival.

Highlights

Air pollution is a complex and dynamic phenomenon involving the exposure of living organisms to harmful airborne substances
Amplification and sequencing of the BenA gene allowed the identification of the 21 isolates collected as belonging to seven different species of the series Versicolores: Aspergillus amoenus, A. creber, A. fructus, A. jensenii, A. protuberus, A. puulaauensis, and A. sydowii
Aspergillus amoenus, A. jensenii, and A. protuberus have been found in bioaerosols in other studies [16,20]

Summary

Introduction

Air pollution is a complex and dynamic phenomenon involving the exposure of living organisms to harmful airborne substances. One of the mechanisms explaining part of the health effects of airborne particles is their ability to synthesize or catalyze the formation of reactive oxygen species (ROS) when they reach the lung cells. These molecules cause oxidative stress and inflammation of the airways. This ability to synthesize and/or catalyze the formation of ROS is determined by the particles’ oxidative potential (OP), which can be measured by biochemical and cell-free assays.

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