Nitroxoline exerts potent anti- <i>Aspergillus fumigatus</i> activity by disrupting copper homeostasis and inducing oxidative stress

ABSTRACT Invasive pulmonary aspergillosis (IPA) caused by Aspergillus fumigatus remains a clinical challenge due to limited therapies and rising antifungal resistance. Here, we evaluated nitroxoline (NTX), an FDA-approved 8-hydroxyquinoline derivative, for its antifungal potential and mechanism of action. NTX exhibited potent in vitro activity against 64 clinical isolates and the AF293 reference strain, delaying conidial maturation and significantly improving survival, reducing pulmonary fungal burden, and alleviating lung inflammation and hyphal invasion in an IPA mouse model. Transcriptomic analysis revealed marked downregulation of the high-affinity Cu transporter ctrC and superoxide dismutase sodB , disrupting the copper homeostasis-oxidative stress axis. Copper supplementation restored hyphal growth and intracellular ROS levels, supporting a mechanism of copper deprivation-induced oxidative stress. These findings demonstrate that NTX exerts strong anti- A . fumigatus effects in vitro and in vivo by perturbing copper homeostasis and inducing oxidative stress, highlighting its unique antifungal potential and providing a conceptual basis for metal-targeted therapeutic strategies against IPA and drug-resistant fungal infections.