CNI-1493 attenuates neuroinflammation and dopaminergic neurodegeneration in the acute MPTP mouse model of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is associated with neurodegeneration of dopaminergic neurons in the substantia nigra. Neuroinflammatory processes have been shown to be a key component of this neurodegeneration and, as such, small molecule compounds which inhibit these inflammatory events are a critical research focus.

OBJECTIVE

CNI-1493 is an anti-inflammatory compound that strongly inhibits macrophages and also stimulates the cholinergic anti-inflammatory pathway. We have examined whether CNI-1493 has a neuroprotective effect in the acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD.

METHODS

CNI-1493 (8 mg/kg i.p.) or placebo administration was started 1 day before MPTP intoxication and repeated daily until sacrifice after MPTP intoxication. C57/Bl6 mice - either treated with CNI-1493 or with placebo - were injected intraperitoneally 4 times at 2-hour intervals with either 20 mg/kg MPTP-HCl or a corresponding volume of saline. Two or 7 days after the end of the MPTP intoxication, the animals were killed and their brains were processed for further analysis.

RESULTS

Administration of CNI-1493 markedly protected tyrosine hydroxylase-positive substantia nigra neurons against MPTP neurotoxicity. CNI-1493 treatment in the MPTP model was also accompanied by a profound reduction of activated microglia within the substantia nigra, as measured by ionized calcium-binding adapter molecule-1 staining.

CONCLUSIONS

These findings support that CNI-1493 could reduce the MPTP-induced toxicity likely by inhibition of neuroinflammatory responses. The neuroprotective effect of CNI-1493 suggests that CNI-1493 might be a valuable neuroprotective candidate in the future treatment of PD.