Sex-dimorphic neuroprotective effect of CD163 in an α-synuclein mouse model of Parkinson's disease

Alpha-synuclein (-syn) aggregation and immune activation represent hallmark pathological events in Parkinsons disease (PD). The PD-associated immune response encompasses both brain and peripheral immune cells, although little is known about the immune proteins relevant for such response. We propose that the upregulation of CD163 observed in blood monocytes and in the responsive microglia in the PD patients is a protective mechanism in the disease. To investigate this, we used the PD model based on intrastriatal injections of murine -syn pre-formed fibrils (PFF) in CD163 knockout (KO) mice and wild-type littermates. CD163KO females revealed an impaired and differential early immune response to -syn pathology as revealed by immunohistochemical and transcriptomic analysis. After 6 months, CD163KO females showed an exacerbated immune response and -syn pathology, which ultimately led to dopaminergic neurodegeneration of greater magnitude. These findings support a novel, sex-dimorphic neuroprotective role for CD163 during -syn-induced neurodegeneration.