ABSTRACT
BACKGROUND: Glycogen synthase kinase-3ß (GSK-3ß) activity plays a central role in motor neuron degeneration. GSK-3ß 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-3ß 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.
Subject(s)
Amyotrophic Lateral Sclerosis/drug therapy , Glycogen Synthase Kinase 3/antagonists & inhibitors , Neuroprotective Agents/therapeutic use , Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/pathology , Analysis of Variance , Animals , Caspase 3 , Choline O-Acetyltransferase/metabolism , Cytochromes c/metabolism , Disease Models, Animal , Glycogen Synthase Kinase 3 beta , Humans , Mice , Mice, Transgenic , Motor Activity/drug effects , Motor Activity/genetics , Motor Neurons/drug effects , Phosphatidylinositol 3-Kinases/metabolism , Poly (ADP-Ribose) Polymerase-1 , Poly(ADP-ribose) Polymerases/metabolism , Single-Blind Method , Spinal Cord/pathology , Superoxide Dismutase/genetics , Time FactorsABSTRACT
Glycogen synthase kinase-3ß (GSK-3ß) has been identified as one of the important pathogenic mechanisms in motor neuronal death. GSK-3ß inhibitor has been investigated as a modulator of apoptosis and has been shown to confer significant protective effects on cell death in neurodegenerative diseases. However, GSK-3ß is known to have paradoxical effects on apoptosis subtypes, i.e., pro-apoptotic in mitochondrial-associated intrinsic apoptosis, but anti-apoptotic in death receptor-related extrinsic apoptosis. In this study, we evaluated the effect of a new GSK-3ß inhibitor (JGK-263) on motor neuron cell survival and apoptosis, by using low to high doses of JGK-263 after 48 h of serum withdrawal, and monitoring changes in extrinsic apoptosis pathway components, including Fas, FasL, cleaved caspase-8, p38α, and the Fas-Daxx interaction. Cell survival peaked after treatment of serum-deprived cells with 50 µM JGK-263. The present study showed that treatment with JGK-263 reduced serum-deprivation-induced motor neuronal apoptosis by inactivating not only the intrinsic, but also the extrinsic apoptosis pathway. These results suggest that JGK-263 has a neuroprotective effect through effective modulation of the extrinsic apoptosis pathway in motor neuron degeneration.