Figure 3. Additional Gα_q-linked receptors regulate APP expression and Aβ release.

hAPP-expressing QBI293 cells were transiently transfected with cDNA encoding the human EP1, EP3, CysLT1 or BLT1 receptors. (A-C) The cells were treated for 36 h with vehicle or with agonist (100 nM 17PGE2 for EP1 and EP3; 1 μM LTD4 for CysLT1; 1 μM LTB4 for BLT1), followed by analysis of (A) APP mRNA [R.Q. values of APP/GAPDH are relative to vehicle-treated cells], (B) APP protein [(top) representative blot and (bottom) quantification of APP with 5685 antibody relative to the vehicle-treated cells, normalized to GAPDH], or (C) Aβ1-40 released into the culture medium. The presented data are the means obtained from a single independent study conducted with each treatment in triplicate. For Aβ1-40 ELISA determinations, each sample was analyzed in triplicate. A second independent study was conducted to confirm the findings (not shown). A two-tailed, t-test was applied to test if the values of the treatment groups differed relative to receptor-transfected cells in the absence of agonist. A one sample t-test was conducted in (C) for the CysLT1 samples, as the Aβ1-40 was below the level of detection in the vehicle group. Error bars represent SEM; *p < 0.05; **p < 0.01; ***p < 0.001. <LOD = below limit of detection.