Can gliotoxin promote oxidative stress and disrupt blood-brain-barrier integrity?

Gliotoxin, a fungal secondary metabolite, has experimentally supported capacity to disturb cellular redox balance and CNS-barrier function. The full sequence from exposure to clinically meaningful neuroimmune entry remains more firmly established mechanistically than in human disease.

Oxidative and endothelial effects

• Gliotoxin’s redox-active disulfide is reduced by glutathione and other intracellular thiols, then reoxidized to generate superoxide and downstream reactive oxygen species (ROS). Thiol binding also compromises glutathione- and protein-based antioxidant defenses.
• Cellular findings include increased ROS, mitochondrial depolarization, ATP depletion, cytochrome-c release, caspase activation, and apoptosis. Neural-cell experiments found reduced astrocyte mitochondrial activity at 300 nM after 18 hours and neuronal effects at 1,000 nM after 5 hours.
• In human iPSC-derived brain microvascular endothelial models, ≥1 μM gliotoxin for 2–24 hours reduced transendothelial electrical resistance and increased fluorescein permeability—complementary evidence of impaired BBB-like barrier function.

Mechanisms and neuroimmune implications

• The endothelial defect was associated with impaired cell–matrix interactions and redistribution of F-actin, without detectable loss of occludin, claudin-5, or ZO-1; it was reported as protein-kinase-C independent. Gliotoxin itself showed low permeability, so endothelial dysfunction did not require substantial toxin transit across the monolayer.
• Barrier dysfunction can increase CNS exposure to circulating cytokines and facilitate immune-cell access. However, leukocyte diapedesis also requires endothelial activation, selectins, ICAM-1/VCAM-1, chemokines, and integrin signaling.
• In mice with experimental autoimmune encephalomyelitis, systemic gliotoxin increased blood–spinal-cord-barrier permeability, CNS inflammation, and demyelination.

Bottom line

• Gliotoxin can promote oxidative stress and disrupt BBB-like endothelial integrity; these changes can plausibly facilitate immune-mediator and immune-cell access to neural tissue. The strongest direct BBB evidence is in vitro at ≥1 μM, while human in-vivo exposure relevance and gliotoxin-induced leukocyte trafficking remain unproven.