Cerebellar spreading depolarization mediates paroxysmal movement disorder

Area of Science:

• Neuroscience
• Genetics
• Neurology

Background:

• Paroxysmal kinesigenic dyskinesia (PKD) is a movement disorder characterized by involuntary movements triggered by sudden motion.
• Mutations in the Proline-rich transmembrane protein 2 (PRRT2) gene are the primary cause of PKD.
• The underlying mechanisms linking PRRT2 dysfunction to dyskinetic episodes remain incompletely understood.

Purpose of the Study:

• To investigate the role of cerebellar spreading depolarization (SD) in the pathophysiology of PRRT2 deficiency-related paroxysmal kinesigenic dyskinesia (PKD).
• To explore whether modulating cerebellar SD can prevent or alleviate dyskinetic movements in a mouse model of PRRT2 deficiency.

Main Methods:

• Utilized Ca2+ imaging to assess neuronal activity in the cerebellum of Prrt2-deficient mice.
• Performed electrophysiological recordings to analyze neuronal firing patterns in Purkinje cells and deep cerebellar nuclei (DCN).
• Investigated the effect of inhibiting cerebellar SD on the occurrence of dyskinetic movements.

Main Results:

• PRRT2 deficiency was found to facilitate the induction of cerebellar spreading depolarization (SD).
• Cerebellar SD was observed to depolarize cerebellar granule cells and Purkinje cells in Prrt2-deficient mice.
• Inhibition of cerebellar SD effectively prevented the occurrence of dyskinetic movements.
• Aberrant neuronal firing patterns in the deep cerebellar nuclei (DCN), temporally coupled to dyskinetic episodes, were identified.

Conclusions:

• Cerebellar spreading depolarization (SD) plays a critical role in the pathogenesis of paroxysmal kinesigenic dyskinesia (PKD) associated with PRRT2 deficiency.
• Targeting cerebellar SD presents a promising therapeutic strategy for treating PRRT2-related paroxysmal disorders.
• This study elucidates a novel mechanism linking genetic defects to specific neuronal network dysfunction in movement disorders.