Adoptive transfer of mitochondrial antigen-specific CD8+ T-cells in mice causes parkinsonism and compromises the dopamine system

The progressive dysfunction and degeneration of dopamine (DA) neurons of the ventral midbrain is linked to the development of motor symptoms in Parkinson’s disease (PD). Multiple lines of evidence suggest the implication of neuroinflammation and mitochondrial dysfunction as key drivers of neurodegenerative mechanisms in PD. Recent work has revealed that loss of the mitochondrial kinase PINK1 leads to enhanced mitochondrial antigen presentation (MitAP) by antigen-presenting cells (APCs), the amplification of mitochondrial antigen-specific CD8+ T cells and the loss of DA neuron terminals markers in the brain in response to gut infection. However, whether mitochondrial antigen- specific T cells are involved in and/or sufficient to cause DA system dysfunction remains unclear. Here, we investigated the effect of mitochondrial autoimmunity by adoptively transferring mitochondrial peptide-specific CD8+ T cells into wild-type (WT) and PINK1 KO mice. We find that this leads to L- DOPA-reversible motor impairment and to robust loss of DA neurons and axonal markers in the striatum in both PINK1 WT and KO mice. Our findings provide direct evidence of the pivotal role played by mitochondrial-specific CD8+ T cell infiltration in the brain in driving PD-like pathology and the development of parkinsonism. Altogether, our data strongly support the hypothesis that MitAP and autoimmune mechanisms play a key role in the pathophysiological processes leading to PD. ### Competing Interest Statement The authors have declared no competing interest.