RESUMEN
Advancing the mechanistic understanding of absence epilepsy is crucial for developing new therapeutics, especially for patients unresponsive to current treatments. Utilizing a recently developed mouse model of absence epilepsy carrying the BK gain-of-function channelopathy D434G, here we report that attenuating the burst firing of midline thalamus (MLT) neurons effectively prevents absence seizures. We found that enhanced BK channel activity in the BK-D434G MLT neurons promotes synchronized bursting during the ictal phase of absence seizures. Modulating MLT neurons through pharmacological reagents, optogenetic stimulation, or deep brain stimulation effectively attenuates burst firing, leading to reduced absence seizure frequency and increased vigilance. Additionally, enhancing vigilance by amphetamine, a stimulant medication, or physical perturbation also effectively suppresses MLT bursting and prevents absence seizures. These findings suggest that the MLT is a promising target for clinical interventions. Our diverse approaches offer valuable insights for developing next generation therapeutics to treat absence epilepsy.
Asunto(s)
Modelos Animales de Enfermedad , Epilepsia Tipo Ausencia , Animales , Epilepsia Tipo Ausencia/fisiopatología , Ratones , Tálamo/fisiopatología , Neuronas/metabolismo , Neuronas/fisiología , Optogenética , Canales de Potasio de Gran Conductancia Activados por el Calcio/metabolismo , Estimulación Encefálica Profunda/métodos , Masculino , Núcleos Talámicos de la Línea Media/fisiologíaRESUMEN
BACKGROUND: The mutations of KCNMA1 BK-type K+ channel have been identified in patients with various movement disorders. The underlying pathophysiology and corresponding therapeutics are lacking. OBJECTIVES: To report our clinical and biophysical characterizations of a novel de novo KCNMA1 variant, as well as an effective therapy for the patient's dystonia-atonia spells. METHODS: Combination of phenotypic characterization, therapy, and biophysical characterization of the patient and her mutation. RESULTS: The patient had >100 dystonia-atonia spells per day with mild cerebellar atrophy. She also had autism spectrum disorder, intellectual disability, and attention deficit hyperactivity disorder. Whole-exome sequencing identified a heterozygous de novo BK N536H mutation. Our biophysical characterization demonstrates that N536H is a gain-of-function mutation with markedly enhanced voltage-dependent activation. Remarkably, administration of dextroamphetamine completely suppressed the dystonia-atonia spells. CONCLUSIONS: BK N536H is a gain-of-function that causes dystonia and other neurological symptoms. Our stimulant therapy opens a new avenue to mitigate KCNMA1-linked movement disorders. © 2020 International Parkinson and Movement Disorder Society.