Fig. 1

GPR37 protein density and mRNA levels in post-mortem brain tissues from neurological controls (NCs) and Parkinson’s disease (PD) subjects. a Immunoblots showing the expression of GPR37 in the SN of NC and PD subjects (Braak PD stage 4, Braak PD 5 and Braak PD 6). Extracts from the human post-mortem SN were analysed by SDS-PAGE and immunoblotted using rabbit anti-GPR37-C and rabbit anti-α-actinin antibodies. The right dashed outlined area (*) is shown with enhanced contrast and corresponds to lane 1 (NC). The different GPR37 forms included precursor (70 kDa), full-length mature (93 kDa) and GPR37 N-terminus-cleaved forms (76 kDa, 52 kDa, 47 kDa, 43 kDa and 39–40 kDa). b Relative quantification of GPR37 protein density in the SN. The immunoblots corresponding to the precursor (Pre) and cleaved GPR37 forms from the NC (n = 5), Braak PD stage 4 (n = 5), Braak PD stage 5 (n = 5) and Braak PD stage 6 (n = 5) subjects were quantified by densitometric scanning. Values were normalized to α-actinin in each lane to correct for protein loading. Results are expressed as the percentage (mean ± SEM) of the NC. *P < 0.05, **P < 0.01 vs NC, one-way ANOVA followed by Dunnett’s post-hoc test. c RT-qPCR assessment of GPR37 mRNA expression in post-mortem SN from NCs (n = 10), Braak PD stage 3/4 (n = 7) and Braak PD stage 5/6 (n = 17) subjects. Mean values of the housekeeping genes (GUS-B, XPNPEP1, AARS and HPRT) were used to normalize samples. Results are expressed as fold-change (mean ± SEM) of the NCs. **P < 0.01 vs NC, one-way ANOVA followed by Dunnett’s post-hoc test