Choroid plexus-CSF-targeted antioxidant therapy protects the brain from toxicity of cancer chemotherapy

For many cancer patients, chemotherapy produces untreatable life-long neurologic effects termed chemo-therapy-related cognitive impairment (CRCI). We discovered that the chemotherapy methotrexate (MTX) adversely affects oxidative metabolism of non-cancerous choroid plexus (ChP) cells and the cerebrospinal fluid (CSF). We used a ChP-targeted adeno-associated viral (AAV) vector approach in mice to augment CSF levels of the secreted antioxidant SOD3. AAV-SOD3 gene therapy increased oxidative defense capacity of the CSF and prevented MTX-induced lipid peroxidation in the hippocampus. Furthermore, this gene ther-apy prevented anxiety and deficits in short-term learning and memory caused by MTX. MTX-induced oxidative damage to cultured human cortical neurons and analyses of CSF samples from MTX-treated lym-phoma patients demonstrated that MTX diminishes antioxidant capacity of patient CSF. Collectively, our findings motivate the advancement of ChP-and CSF-targeted anti-oxidative prophylactic measures to relieve CRCI.