Berberine improves motor deficits in the spastic paraplegia SPG7 mutant mice

Abstract

Hereditary spastic paraplegia type 7 (SPG7) is a neurodegenerative disorder characterized by progressive motor impairment and cerebellar dysfunction. Mutations in the SPG7 gene, encoding the mitochondrial metalloprotease paraplegin, disrupt mitochondrial homeostasis and lead to neuronal vulnerability and deficits in motor coordination. Recent studies have identified defective flickering of the mitochondrial permeability transition pore (mPTP) in SPG7 models, suggesting that altered pore dynamics may represent a functional biomarker of mitochondrial dysfunction. Here, we investigated whether pharmacological modulation of mPTP activity could improve mitochondrial function and motor performance in SPG7 models. Mitochondrial flickering was assessed in vitro, while motor behavior was evaluated in vivo following chronic treatment with berberine, a natural isoquinoline alkaloid known to modulate mitochondrial bioenergetics. Spg7-/- mice and age-matched Spg7+/ littermate controls received daily oral berberine administration for several weeks, and motor coordination was assessed using the accelerating rotarod test. Untreated Spg7-/- mice exhibited reduced rotarod performance compared with controls, indicating impaired motor coordination. Berberine treatment significantly improved motor performance in pre-symptomatic mutant mice. These findings indicate that pharmacological modulation of mitochondrial permeability transition pore dynamics can ameliorate motor dysfunction associated with SPG7 deficiency and highlight mPTP flickering as a functional readout of mitochondrial health.