AZD2858 GSK-3 inhibitor

AZD2858 is a selective GSK-3 inhibitor with an IC50 of 68 nM, inhibits tau phosphorylation at the S396 site, activates Wnt signaling pathway. This compound treatment (1 μM, 12 h) on primary isolated human osteoblast-like cells results in a 3-fold increase of β-catenin levels. [1] It causes β-catenin stabilisation in human and rat mesenchymal stem cells, stimulates hADSC commitment towards osteoblasts and osteogenic mineralisation in vitro. [2]

Tau phosphorylation assay

NIH-3T3 cells expressing 4-repeat Tau are used to assess functional activity of AZD2858 in vitro. The cells are grown in DMEM media and 2 mM L-glut, and 10% HiFCS, and plated at a concentration of 6×10⁵ cells/well in 6-well plates. In each experiment, this compound is dosed in triplicates at a concentration of 1, 10, 100, 500, 1000, 2000 and 10,000 nM. Cells are treated for 4 h prior to cell lysis using 100 μL ice cold lysis buffer (0.5% NP-40, 10 mM Tris, pH 7.2, 150 mM NaCl, 2 mM EDTA). A suspension is made with addition of protease and phosphatase inhibitors: 50 mM NaF, 0.2 mM NaVO4 and Cocktail Protease inhibitors. The solution is then snap frozen at −80 °C for at least 1 h, before thawing on ice and lysate clarification by centrifugation, followed by Western blot according to standard protocols. After blocking, the blots are exposed to the primary antibody, Phospho-Ser396-tau (1:1000) over night, washed and incubated with the secondary antibody (donkey anti-rabbit, 1:5000), followed by a final wash. For re-probing, the primary antibody Tau5 (1:200) and the secondary horseradish peroxidase linked antibody (sheep anti-mouse, 1:10000) are used. All blots are developed using ECL Western blot detection reagents, Kodak X-ray films, quantified using densitometric analysis, and the ratio of S396 tau to total tau (tau5) is calculated.

In rats, oral AZD2858 treatment causes a dose-dependent increase in trabecular bone mass compared to control after a two-week treatment with a maximum effect at a dose of 20 mg/kg once daily (total BMC: 172% of control). A small but significant effect is also seen at cortical sites (total BMC: 111% of control). [1] This compound (30 μmol/kg) on rats daily for up to 3 weeks shows an increase in both mineral density (of 28% at 2 weeks and 38% at 3 weeks) and mineral content (of 81% at 2 weeks and 93% at 3 weeks) in the calluses. This treatment makes the fractures heals more rapidly, with a bony callus without an obvious endochondral component. [3] It produces time-dependent changes in serum bone turnover biomarkers and increases bone mass over 28 days exposure in rats. After 7 days, this compound increases the bone formation biomarker P1NP, and reduces the resorption biomarker TRAcP-5b, indicating increased bone anabolism and reduced resorption in rats. [2]