Berberine Suppresses Pathogenic Fungus <i>Aspergillus fumigatus</i> Hyphal Growth via Mitochondrial Fragmentation-Induced ROS Elevation and Hog1-MAPK Activation

Berberine (BER), a natural isoquinoline alkaloid, exhibits broad-spectrum antifungal activity, yet its mechanism against <i>Aspergillus fumigatus</i>─a leading cause of invasive fungal infections─remains poorly understood. Here, we aim to unveil the mechanism of BER against the pathogenicity of <i>A. fumigatus</i> through mitochondrial dynamics and related pathways. <i>In vitro</i> assays revealed that berberine treatment triggered mitochondrial fragmentation, resulting in reactive oxygen species (ROS) overaccumulation. Subsequent proteomic analyses identified Hog1-MAPK as the central signaling hub activated by ROS stress. Upon activation, Hog1 localizes to the nucleus. ROS scavenging (<i>N</i>-acetylcysteine (NAC) treatment) abolished BER's antifungal effects, confirming the ROS-Hog1-cell cycle axis. Crucially, in a murine invasive aspergillosis model, BER reduced the fungal burden in lungs and improved survival rates. Thus, we demonstrate that berberine suppresses <i>A. fumigatus</i> growth by disrupting mitochondrial dynamics, elevating reactive ROS, and activating the Hog1-MAPK signaling cascade, ultimately inducing cell cycle arrest. Our findings unveil a previously unrecognized mechanism linking mitochondrial morphology dysregulation to cell cycle control in fungi and establish BER as a promising therapeutic agent targeting mitochondrial-ROS-Hog1 signaling in <i>A. fumigatus</i> infections.