Characterization and pro-inflammatory responses of spore and hyphae samples from various mold species

Abstract

Mold particles from <i>Aspergillus fumigatus, Penicillium chrysogenum, Aspergillus versicolor</i>, and <i>Stachybotrys chartarum</i> have been linked to respiratory‐related diseases. We characterized X‐ray‐inactivated spores and hyphae fragments from these species by number of particles, morphology, and mycotoxin, β‐glucan and protease content/activity. The pro‐inflammatory properties of mold particles were examined in human bronchial epithelial cells (BEAS‐2B) and THP‐1 monocytes and phorbol 12‐myristate 13‐acetate (PMA)‐differentiated THP‐1. Spores from <i>P. chrysogenum</i> and <i>S. chartarum</i> contained some hyphae fragments, whereas the other preparations contained either spores or hyphae. Each mold species produced mainly one gelatin‐degrading protease that was either of the metallo‐ or serine type, while one remains unclassified. Mycotoxin levels were generally low. Detectable levels of β‐glucans were found mainly in hyphae particle preparations. PMA‐differentiated THP‐1 macrophages were by far the most sensitive model with effects in the order of 10 ng/cm². Hyphae preparations of <i>A. fumigatus</i> and <i>P. chrysogenum</i> were more potent than respective spore preparations, whereas the opposite seems to be true for <i>A. versicolor</i> and <i>S. chartarum</i>. Hyphae fragments of <i>A. fumigatus, P. chrysogenum</i>, and <i>A. versicolor</i> enhanced the release of metalloprotease (proMMP‐9) most markedly. In conclusion, species, growth stage, and characteristics are all important factors for pro‐inflammatory potential.