X5050, a REST inhibitor, has an EC50 of 2.1 μM.

X5050 (100 μM, 1 day) induces a dosedependent decrease in the REST isoform in protein level[1]. Western Blot Analysis[1]Cell Line: NSCs. Concentration: 100 μM. Incubation Time: One day. Result: Induced a dosedependent decrease in the 122 kDa longer REST isoform.

X5050, administered in two intraventricular injections (2 x 2µl of 20 mM) in a 10% DMSO aqueous solution, demonstrates activity in Huntington's Disease (HD) contexts. Utilizing 12-week-old male C57Bl6 mice as an animal model, the compound resulted in a significant increase in Brain-Derived Neurotrophic Factor (BDNF) expression, alongside a decrease in both Darpp32 and Snap25 expressions, as evidenced by Quantitative Reverse Transcription PCR (QRT-PCR) in the lesioned versus contralateral striatum. Additionally, it was observed that X5050 significantly elevated the levels of the Bdnf II splice variant, which contains exon II, whereas the levels of Bdnf IV splice variant remained unchanged.