Fig. 2

Effects of LRRK2 inhibitors on dyskinesia in 6-OHDA parkinsonian rats. a The panel is a schematic representation of the experimental design. Rats were unilaterally injected with 6-OHDA in the left MFB. After 15 days, the extent of the lesion was evaluated upon apomorphine answer. Two months after the 6-OHDA injection, fully lesioned rats (>200 controlateral turns) were chronically treated with L-DOPA. LRRK2 inhibitors were administrated to low dyskinetic animals with a single intrastriatal (i.s.) injection after 2 weeks of L-DOPA treatment. LIDs onset and severity were evaluated by AIMs scoring. b IN-1 (5 nmol), LRRK2 inhibitor III (5 nmol) or vehicle (5 μl 0.5 % DMSO) were stereotaxically injected in the ipsilateral striatum of low dyskinetic rats. I.s. injections were performed 6 h before the daily L-DOPA administration and the evaluation of AIMs were carried out from 20 to 140 min after L-DOPA. Both inhibitors were able to induce a significant increase in the AIMs score compared to vehicle injected rats and to pre-surgery values (n = 7; −18 h: ***p < 0.001, DYS vs DMSO/IN-1/Inh. III. 6 h: ***p < 0.001, DYS vs DMSO/IN-1/Inh. III. 54 h: ***p < 0.001, DMSO vs IN-1/Inh. III/DYS. IN-1: ***p < 0.001, 54 h vs −18 h/6 h. Inhibitor III: ***p < 0.001, 54 h vs −18 h/6 h vs 54 h; two-way ANOVA followed by Bonferroni post-hoc test). c-e Both inhibitors significantly increased dyskinesia induction, as indicated by AIMs scoring during the single last observation session (54 h; E) (n = 7; 40 min, DMSO vs IN-1/Inh. III: *p < 0.05, DMSO vs DYS: **p < 0.01; 60 min, DMSO vs Inh. III: **p < 0.01, DMSO vs DYS: ***p < 0.001; 80 min, DMSO vs DYS: ***p < 0.001; 100 min, DMSO vs Inh. III: **p < 0.01, DMSO vs DYS: ***p < 0.001; 120 min, DMSO vs Inh. III: **p < 0.01, DMSO vs DYS: ***p < 0.001; two-way ANOVA plus Bonferroni post-hoc test). f The ipsilateral striatum from rats displaying a dyskinetic behaviour (Dys), non dyskinetic rats (Non Dys), Non Dys animals sacrificed 6 h after Inh-III injection (Inh-III 6 h) or Non Dys animals sacrificed 54 h after Inh-III injection (Inh-III 54 h) were analyzed by WB to evaluate the levels of LRRK2 phosphorylation at Ser-935 site (P-935). g The graph illustrates LRRK2 phosphorylation normalized upon total LRRK2 (n = 3; One-way Anova: *p < 0.01 Non Dys versus Dys #p < 0.05 Non Dys versus Inh-III 54 h). Data are expressed as mean ± SEM