Fig. 4: GPR37 and ADAM-10 protein density in Alzheimer’s disease post-mortem brain.

Representative immunoblots showing the expression of GPR37 in the prefrontal cortex (PFC) (A) and striatum (B) of neurological controls (NCs) and Alzheimer’s disease (AD) patients (Braak AD stage V/VI). Myelin was removed from samples and non myelin extracts were analysed by SDS-PAGE and immunoblotted using antibodies against GPR37 and ADAM-10. Different GPR37 forms were identified including the full-length (FL; black arrow), post-translationally modified FL (white arrow) and GPR37 N-terminus cleaved forms (squares). Relative quantification of GPR37 and ADAM-10 protein density in the PFC (C) and striatum (D). For GPR37, the immunoblots corresponding to the FL (arrows), and 39–47 kDa (white square) forms were quantified by densiometric scanning. The sum of all receptor forms (total), including the 52 kDa form (black square), was also measured. For ADAM-10, the protein bands corresponding to the proADAM-10 (immature) and active (mature) forms of the protease were quantified by densiometric scanning. The levels of mature ADAM-10 were normalized by the total (immature + mature) ADAM-10 band density. Values were normalized to β-tubulin in each lane to correct for protein loading. Results are expressed as the percentage (mean ± SEM; PFC: n = 5 per group; Striatum: n = 8–10 per group) of the NC. *P < 0.05 vs NC, Student’s t test.