Proteomic and Phosphoproteomic Landscapes of Azole Resistance in Aspergillus fumigatus Biofilm Exposed to Voriconazole

Aspergillus fumigatus, an opportunistic and allergenic pathogenic fungus, is responsible for a range of clinical disorders in humans, including invasive aspergillosis (IA), which can lead to severe infections in immunocompromised individuals. Unfortunately, the emergence of azole resistance has become a significant challenge in combating IA, necessitating further investigations into the underlying mechanisms of resistance. In this study, we conducted an integrated proteomic and phosphoproteomic analysis of biofilm proteins from both azole-resistant and wildtype strains of A. fumigatus under voriconazole pressure. Our proteomic analysis identified 148 upregulated and 146 downregulated proteins in the azole-resistant strains, while phosphoproteomic analysis revealed 316 upregulated phosphopeptides and 109 downregulated phosphopeptides, suggesting extensive phosphorylation modifications associated with azole resistance. Upon excluding the impact of protein changes, we identified 133 proteins with differential expression solely at the phosphorylation level, comprising 104 upregulated and 29 downregulated proteins. Functional annotation and analysis highlighted the significance of these differentially expressed phosphoproteins in cell wall integrity, filamentous growth, and high-osmolarity stress response, with 33 MAPK pathway-associated proteins displaying phosphopeptide level regulation. These findings provide valuable insights into the mechanisms behind azole resistance in Aspergillus fumigatus and offer potential new drug targets for combating this pathogenic fungus in humans.