Evaluate neuroprotective effects of AZ257 in the EAE mouse model of multiple sclerosis and its mechanism of action involving anti-inflammatory effects by inhibiting astrocyte activation.  

Astrocyte activation plays a critical role in the inflammatory process in multiple sclerosis. Recent studies suggest dopamine plays a pivotal role in the regulation of the immune system including autoreactive T-cells such as Th17 cells and astrocytes in multiple sclerosis. AZ257 is a novel dopamine transporter inhibitor that crosses the blood brain barrier and can inhibit astrocyte activation.

EAE model was induced in female C57BL/6 mice (9-12 weeks old) with MOG35-55 and pertussis toxin. Mice were treated with methylprednisolone (EAE-MP), AZ257 (EAE-AZ257) or vehicle (EAE-veh) from day 1-10 after EAE induction. Normal control group underwent identical paradigms. Mice were monitored daily and EAE scoring was performed during day 7-23. Audible and ultrasound vocalizations were measured on day 24. GFAP and inflammatory cytokines expressions were measured with immunofluorescence (IF) and polymerase chain reaction (PCR) separately after brain tissues were obtained.

EAE model was successfully induced as shown by EAE score curve in EAE-veh group. Both EAE-AZ257 and EAE-MP groups showed significantly decreased scores comparing to EAE-veh group from day 12 until the end of study.  Treatment with AZ257 significantly inhibited both types of vocalizations (P<0.001), while in EAE-MP group, statistical significance was only seen in audible vocalizations. Increased expression of GFAP was seen in the amygdala of EAE-veh group compared to control group, and the expression was significantly decreased in EAE-AZ257 (p<0.001) and EAE-MP (p<0.05) groups. Expression of inflammatory markers including IL-6, IL-1b, TNF-α, INF- γ was significantly increased in the brain tissue of EAE-veh group and the expressions were significantly decreased in EAE-AZ257 and EAE-MP groups.

AZ257 showed possible neuroprotective and anti-inflammatory effects and inhibited astrocyte activation in the EAE mouse model.