Anti-TLR2 immunotherapy modulates neuron-to-oligodendrocyte propagation of α-synuclein in mouse and human models

Intracellular accumulation of α-synuclein (αSyn) aggregates is a hallmark of synucleinopathies, such as Parkinson’s disease (PD) and multiple system atrophy (MSA). In MSA, αSyn aggregates form glial cytoplasmic inclusions (GCIs) in oligodendrocytes, despite their low expression of αSyn. Here, we demonstrate that neuron-to-oligodendrocyte propagation of αSyn, via Toll-like receptor 2 (TLR2) contributes to GCI formation. Male transgenic mice expressing the A53T mutant human αSyn exclusively in neurons, and the preformed fibril injection model exhibited MSA-like pathology, including GCI formation, gliosis, and neuroinflammation in the white matter. Notably, administration of NM-101, an anti-TLR2 antibody, significantly alleviated these pathological features. Transcriptome analyses revealed demyelination-related features in MSA oligodendrocytes and experimental models. Elevated TLR2 expression in MSA oligodendrocytes inversely correlated with MBP expression, and the correlation was absent in PD. In the transgenic mouse model, NM-101 administration rescued the demyelination phenotype. These findings highlight anti-TLR2 immunotherapy as a potential disease-modifying approach for MSA. The pathological mechanisms underlying multiple system atrophy (MSA) remain unclear. Here, the authors show in mouse and human MSA models that α-synuclein spreads from neurons to oligodendrocytes via TLR2 leading to myelination defects, and that blocking TLR2 prevents glial cytoplasmic inclusions and myelin damage.