Methylene blue protects oligodendroglial cell models of multiple systems atrophy against hydrogen peroxide-mediated...

Multiple Systems Atrophy (MSA) is a rare, neurodegenerative disorder associated with impaired alpha (α)-synuclein (α-syn) protein function. α-syn can aggregate within oligodendrocytes, activating oxidative stress pathways and ultimately leading to cell death. Point mutations in the α-syn gene (SNCA) are associated with MSA-A53E and G51D, but cases are mainly idiopathic. Methylene Blue (MB) is an organic dye that has been demonstrated to attenuate oxidative stress in cell models of Parkinson's and Huntington's disease. We hypothesized that MB would protect α-syn stably transfected oligodendroglial cell models of MSA against hydrogen peroxide (H₂O₂)-induced cellular stress. We used four α-syn stably transfected OLN-93 rat oligodendroglial cell lines expressing either an empty plasmid (EP), overexpressed humanized wild-type α-syn (WT-α-syn), or humanized α-syn with either point mutation (A53E-α-syn, G51D-α-syn). Upon 3 h (h) pre-treatment of OLN-93 cells with MB, followed by 1 h or 3 h exposure to H₂O₂, we report that MB does not enact toxic effects but rather substantially improves cell viability and metabolic capability and lowers H₂O₂-induced cell death in the OLN-93 MSA cell models. MB also significantly reduced H₂O₂-induced early (1 h) ROS production in the cytosol and mitochondria and the expression of oxidative stress and modified antioxidant-related proteins, including Nuclear factor erythroid 2-related factor 2 (NRF2), affiliated Kelch-like ECH-associated protein 1 (KEAP1), Heme Oxygenase 1 (HO1), and Adenosine Monophosphate-Activated Protein Kinase (AMPK) after 3 h exposure. Our current data suggest a novel glioprotective role for MB in MSA pathology, specifically against H₂O₂-mediated oxidative injury, and invite future work to investigate MB glioprotection in other in vivo MSA models.