TREM2 mediates parkinsonism-like neurodegeneration in carbon disulfide-induced neurotoxicity

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by progressive loss of dopaminergic neurons and aggregation of α-Synuclein (α-Syn). While both genetic and environmental factors are implicated in PD pathogenesis, the mechanisms underlying neurodegeneration induced by environmental toxins and associated genetic responses remain largely unknown. Recently, triggering receptor expressed on myeloid cells 2 (TREM2) has been proven to be a critical mediator of toxin-induced motor neuron degeneration. Using GWAS data, this study employed Mendelian randomization analysis and revealed a significant association between elevated serum TREM2 levels and increased risk of secondary PD. Further experiments used 20 male wild-type mice and 20 male TREM2 KO mice exposed to corn oil or carbon disulfide (an environmental toxin associated with PD), respectively, revealed that TREM2 acts as a molecular switch, amplifying environmental neurotoxicity through the excessive activation of microglia. In contrast, Trem2 KO exhibited pronounced neuroprotective effects, including reduced α-Syn aggregation in the substantia nigra, alleviated nigral neuronal structural damage, diminished neuroinflammation, and improved motor coordination in mice. Finally, protein docking and interaction analysis verified that TREM2 recognizes α-Syn and participates in PD-related pathological events, including neuroinflammation and mitochondrial damage. In summary, the present study identifies TREM2 as a pivotal mediator in environmentally induced Parkinsonian syndromes, providing novel insights into the mechanisms underlying neurodegeneration due to environmental toxin exposure and offering potential targets for precise therapeutic interventions.