In vitro study | CHIR 98014 inhibits human GSK-3β with a K I value of 0.87 nM. CHIR 98014 was strongly effective in mice for GSK-3. CHIR 98014 is a competitive inhibitor of ATP, acting GSK-3 against 20 other protein kinases including CDC2, erk2, tie2,KDR, etc., with a selectivity of 500-fold to 1000-fold or more. CHIR 98014 inhibits CDC2 with an IC50 of 3.7 μm. However, CHIR 98014 had a similar effect on the highly homologous alpha and beta subtypes GSK-3, but there was a clear difference between the GSK-3 and the closest homologs, cdc2 and erk2. Treatment with insulin receptors expressing CHO-IR cells or primary murine hepatocytes increased CHIR98014 concentrations resulting in a 2-to 3-fold increase in GS activity. The concentration at which CHIR 98014 caused CHO-IR and mouse hepatocytes to reach a half maximal GS stimulation response was 106 and 107 nM, respectively. |
In vivo study | GSK-3 inhibitors CHIR-98014 act on Type I skeletal muscle isolated from lean Zucker and insulin-resistant ZDF mice to activate GS activity. Soleus muscle isolated from ZDF mice was clearly resistant to GS-activated insulin, but muscles isolated from lean Zucker mice responded to 500 nM CHIR 98014 to the same extent, with an increase of 40%. Insulin and CHIR 98014 activated GS in the isolated muscles of lean Zucker mice were much stronger than in the isolated muscles of ZDF mice. Action of CHIR 98014 or insulin on these cells and muscle does not alter the overall GS activity. At the same time, CHIR 98014 did not affect the insulin dose response in muscle isolated from lean animals. CHIR 98014 acts on db/db mice, ZDF mice, ob/ob mice, diet-induced diabetic C57BL/6 mice, and glucose-resistant SHHF mice to reduce hyperglycemia and promote glucose excretion. In addition, CHIR98014 acts on the cerebral cortex of newborn rats to reduce the phosphorylation level of tau protein Ser396 site. |