Over expression of TPH2 was validated by standard western blot procedure (Fig. S1†) followed by chemiluminescent imaging.62 (link) Briefly, protein was extracted from cells using a Urea-CHAPS buffer (8 M Urea, 1% CHAPS, and 20 mM HEPES, pH 8.0) and run on a Bis–Tris resolving gel. Proteins were transferred to a polyvinylidene difluoride membrane (PVDF), blocked with 5% milk and probed with antibodies to TPH2 (Abcam ab111828) and GAPDH (Proteintech 60004) overnight at 4 °C. HRP-conjugated secondary antibodies (Jackson ImmunoResearch) were then incubated for 2 hours at room temperature with ECL Chemiluminescent Substrate Reagent (Thermo Scientific) applied for detection.