TDZD-8

Kinase experiment:

GSK-3 activity is assayed in 50 mM Tris-HCl, pH 7.5, 10 mM MgCl2, 1 mM EGTA, and 1 mM EDTA buffer, at 37°C, in the presence of 15 μM GS-1 (substrate), 15 μM [γ-32P]ATP in a final volume of 12 μL. After 20 min incubation at 37°C, 4 μL aliquots of the supernatant are spotted onto 2×2 cm pieces of Whatman P81 phosphocellulose paper, and 20 s later, the filters are washed four times (for at least 10 min each time) in 1% phosphoric acid. The dried filters are transferred into scintillation vials, and the radioactivity is measured in a liquid scintillation counter. Blank values are subtracted, and the GSK-3β activity is expressed in picomoles of phosphate incorporated in GS-1 per 20 min or in percentage of maximal activity[1].

Animal experiment:

Apomorphine hydrochloride is administered (0.5 mg/kg). L-dopa (25 mg/kg) plus benserazide-HCl (6.25 mg/kg) are given once-daily. TDZD8, a non-ATP competitive inhibitor of GSK-3β, is dissolved in 10% DMSO and is administered i.p. (TDZD8-L group, 1 mg/kg; TDZD8-H group, 2 mg/kg, respectively) 30 min prior to L-dopa intake for 3 weeks. (±)-1-Phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride (SKF38393), a D1 Dopamine receptor agonist, is dissolved in saline and is administered i.p. (SKF38393-L group, 5 mg/kg; SKF38393-H group, 10 mg/kg, respectively) 30 min prior to L-dopa intake for 3 weeks[2].

References:

[1]. Martinez A, et al. First non-ATP competitive glycogen synthase kinase 3 beta (GSK-3beta) inhibitors: thiadiazolidinones (TDZD) as potential drugs for the treatment of Alzheimer's disease. J Med Chem. 2002 Mar 14;45(6):1292-9.
[2]. Xie CL, et al. Inhibition of Glycogen Synthase Kinase-3β (GSK-3β) as potent therapeutic strategy to ameliorates L-dopa-induced dyskinesia in 6-OHDA parkinsonian rats. Sci Rep. 2016 Mar 21;6:23527.
[3]. Sun A, et al. GSK-3β controls autophagy by modulating LKB1-AMPK pathway in prostate cancer cells. Prostate. 2016 Feb;76(2):172-83.