Skip to main content
. 2020 May 1;6(18):eaaz7001. doi: 10.1126/sciadv.aaz7001

Fig. 6. Validation of RasGRP1 and its targets and their up-regulation in monkey model of PD.

Fig. 6

(A) Quantification (ratio) of selected examples from LC-MS/MS of proteins in indicated groups in comparison to intact WT striatum. (B and C) Western blotting and quantification of indicated proteins from the intact and lesioned striatum of WT and RasGRP1 KO mice after l-DOPA treatment. Error bars represent means ± SEM (n = 3). *P < 0.05, ***P < 0.001, and ****P < 0.0001 using one-way ANOVA followed by Tukey’s multiple comparison test. ###P < 0.001 by unpaired Student’s t test. Protein expression levels of RASGRP1 and its selected targets in the brain of parkinsonian and dyskinetic monkeys. (D) Experimental design. (E to G) Representative blot and Western blot analysis of striatal TH (E), RASGRP1, GAD1/2, GFAP, and PDE2A protein levels in the MFG (F) and putamen (G) of untreated (control), MPTP−, and MPTP + l-DOPA–treated monkeys. Error bars represent means ± SEM. [TH: control, MPTP, and MPTP + l-DOPA (n = 5); RASGRP1: control (n = 5), MPTP (n = 5), and MPTP + l-DOPA (n = 4); GAD1/2, GFAP, and PDE2A: MFG: control, MPTP, and MPTP + l-DOPA (n = 4); and putamen: control, MPTP (n = 5), and MPTP + l-DOPA (n = 4)]. Representative blots of each marker immunodensity comparing the experimental groups are shown. GAPDH was used to normalize for variations in loading and transfer. Dots represent the single values. *P < 0.05 by Mann-Whitney test compared to control group. (H) RASGRP1 transcript in MPTP-treated monkeys with or without l-DOPA administration. Error bars illustrate the means ± SEM [control, MPTP, and MPTP + l-DOPA (n = 5)]. **P < 0.01 by Mann-Whitney test compared to control group. (I) Mechanisms of RasGRP1-induced dyskinesia. Model depicts RasGRP1 is up-regulated during LID activates Rhes and forms complexes with H-Ras to signal ERK and with Rheb to signal mTOR. These dual complexes, in parallel, activates ERK and mTOR signaling, exerting a profound cellular and molecular changes in the striatum via protein synthesis and/or posttranslational modifications, which will influence the onset and progression of LID. Drugs or gene depletion strategies that block RasGRP1 may improve the therapeutic efficacy of l-DOPA by diminishing LID, the debilitating side effects observed in patients with PD. Photo credit: Erwan Bezard, Université de Bordeaux.