Mediating ferritinophagy and ferroptosis: a novel strategy against <i>Staphylococcus aureus</i> infection from a Kudzu root endophytic fungus

ABSTRACT Serious Staphylococcus aureus infections pose a major global public health challenge. However, the escalating problem of antibiotic resistance has led to a progressive decline in effective therapeutic options. In this study, we demonstrated that Aspergillus aureoles GGNSJ001, a bioactive compound isolated from endophytic fungi of Kudzu root, effectively inhibits S. aureus biofilm formation in vitro . Further analysis revealed that the ability of S. aureus to adhere to and invade RAW 264.7 cells was attenuated by A. aureoles GGNSJ001 pre-treatment. To explore the underlying mechanism, an S. aureus -infected macrophage model was established, and the effect of A. aureoles GGNSJ001 on oxidative stress and ferroptosis was assessed. It was shown in the results that the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) were elevated by A. aureoles GGNSJ001 treatment, while the expression of superoxide dismutase (SOD) and glutathione (GSH) was reduced. Through immunofluorescence (IF) and qRT-PCR analyses, it was further confirmed that lipid peroxidation and Fe 2+ accumulation were promoted, and the expression of key ferroptosis-related genes ACSL4 , ALOX15 , TFR1 , and GPX4 were reversed by A. aureoles GGNSJ001, leading to effective control of S. aureus infection. Mechanistically, it was identified that ferroptosis driven by the NCOA4–FTH1 axis constitutes the core event through which the antibacterial effects of A. aureoles GGNSJ001 are exerted. In summary, this study systematically illustrates how A. aureoles GGNSJ001 activates ferritinophagy via the NCOA4–FTH1 pathway, thereby enhancing oxidative stress and triggering ferroptosis to clear S. aureus -infected macrophages. These findings offer novel mechanistic insights and a promising therapeutic strategy for combating antibiotic-resistant bacterial infections. IMPORTANCE This work addresses the critical challenge of antibiotic-resistant Staphylococcus aureus infections by identifying a novel antifungal strategy. We demonstrate that a natural compound from the Aspergillus aureoles GGNSJ001 can clear infected immune cells by hijacking a specific cell death pathway known as ferroptosis. This represents a paradigm shift, as it targets the host's cellular machinery to combat bacteria rather than the pathogen directly, offering a promising new avenue to overcome drug resistance. The findings provide a foundational framework for developing innovative host-directed therapies against persistent bacterial infections.