Background: Glycogen synthase kinase-3β (GSK-3β) activity plays a central role in motor neuron degeneration. GSK-3β inhibitors have been shown to prolong motor neuron survival and suppress disease progression in amyotrophic lateral sclerosis (ALS). In this study, we evaluated the therapeutic effects of a new GSK-3b inhibitor, JGK-263, on ALS in G93A SOD1 transgenic mice.

Methods: Previously, biochemical efficacy of JGK-263 was observed in normal and mutant (G93A) hSOD1-transfected motor neuronal cell lines (NSC34). Based on these previous results, we administered JGK-263 orally to 93 transgenic mice with the human G93A-mutated SOD1 gene. The mice were divided into three groups: a group administered 20mg/kg JGK-263, a group administered 50mg/kg JGK-263, and a control group not administered with JGK-263. Clinical status, rotarod test, and survival rates of transgenic mice with ALS were evaluated. Sixteen mice from each group were selected for further biochemical study that involved examination of motor neuron count, apoptosis, and cell survival signals.

Results: JGK-263 administration remarkably improved motor function and prolonged the time until symptom onset, rotarod failure, and death in transgenic mice with ALS compared to control mice. In JGK-263 groups, choline acetyltransferase (ChAT) staining in the ventral horn of the lower lumbar spinal cord showed a large number of motor neurons, suggesting normal morphology. The neuroprotective effects of JGK-263 in ALS mice were also suggested by western blot analysis of spinal cord tissues in transgenic mice.

Conclusion: These results suggest that JGK-263, an oral GSK-3β inhibitor, is promising as a novel therapeutic agent for ALS. Still, further biochemical studies on the underlying mechanisms and safety of JGK-263 are necessary.