Effects of methylprednisolone on Aspergillus fumigatus 293 gene expression

Corticosteroid use has epidemiologically been associated with invasive aspergillosis. We found that hydrocortisone and MP in physiological concentrations cause a change in morphology of A. fumigatus 293 growth with a less dense core, and straighter outgrowth of longer hyphae. Treated with MP, we found a differential expression of genes annotated to cell wall structure, and to cell cycle programme compared to untreated control, which could explain the changes in morphology. The up-regulation of genes encoding for toxins, iron acquisition, and cell wall components enforcing oxidative stress resistance would theoretically result in a more pathogenic A. fumigatus phenotype. Upregulation of pathways involved in DNA-repair might indicate on genotoxic effects of MP. Overall design: Examination of test setting with 0.5 microM methylprednisolone versus control setting without methylprednisolone. Identification of differentially expressed genes (DEGs) was performed on the pooled data of the 3 samples treated with MP versus the 3 untreated control samples, with correction for the total number of reads per group.