RESUMEN
Amyotrophic lateral sclerosis (ALS) is a rapidly progressing neurodegenerative disease, characterized by motor neuron (MN) death, for which there are no truly effective treatments. Here, we describe a new small molecule survival screen carried out using MNs from both wild-type and mutant SOD1 mouse embryonic stem cells. Among the hits we found, kenpaullone had a particularly impressive ability to prolong the healthy survival of both types of MNs that can be attributed to its dual inhibition of GSK-3 and HGK kinases. Furthermore, kenpaullone also strongly improved the survival of human MNs derived from ALS-patient-induced pluripotent stem cells and was more active than either of two compounds, olesoxime and dexpramipexole, that recently failed in ALS clinical trials. Our studies demonstrate the value of a stem cell approach to drug discovery and point to a new paradigm for identification and preclinical testing of future ALS therapeutics.
Asunto(s)
Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Células Madre Embrionarias/citología , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Células Madre Pluripotentes Inducidas/citología , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Neuronas Motoras/citología , Neuronas Motoras/efectos de los fármacos , Inhibidores de Proteínas Quinasas/análisis , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Esclerosis Amiotrófica Lateral/enzimología , Esclerosis Amiotrófica Lateral/patología , Animales , Benzazepinas/química , Benzazepinas/farmacología , Diferenciación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Colestenonas/química , Colestenonas/farmacología , Glucógeno Sintasa Quinasa 3/metabolismo , Humanos , Indoles/química , Indoles/farmacología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ratones , Ratones Transgénicos , Neuronas Motoras/enzimología , Mutación , Inhibidores de Proteínas Quinasas/química , Proteínas Serina-Treonina Quinasas/metabolismo , Relación Estructura-Actividad , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Superóxido Dismutasa-1RESUMEN
The motor neuron disease spinal muscular atrophy (SMA) results from mutations that lead to low levels of the ubiquitously expressed protein survival of motor neuron (SMN). An ever-increasing collection of data suggests that therapeutics that elevate SMN may be effective in treating SMA. We executed an image-based screen of annotated chemical libraries and discovered several classes of compounds that were able to increase cellular SMN. Among the most important was the RTK-PI3K-AKT-GSK-3 signaling cascade. Chemical inhibitors of glycogen synthase kinase 3 (GSK-3) and short hairpin RNAs (shRNAs) directed against this target elevated SMN levels primarily by stabilizing the protein. It was particularly notable that GSK-3 chemical inhibitors were also effective in motor neurons, not only in elevating SMN levels, but also in blocking the death that was produced when SMN was acutely reduced by an SMN-specific shRNA. Thus, we have established a screen capable of detecting drug-like compounds that correct the main phenotypic change underlying SMA.