A Flupirtine Benzyl Carbamate Improves Neurocognitive Deficits and Molecular Pathology in the Cln6nclf Mouse

Neuronal ceroid lipofuscinosis type 6 (CLN6) is a fatal, autosomal recessive neurodegenerative disorder characterized by cognitive/motor impairment, vision loss, as well as neuronal loss and gliosis in the brain, and premature death. Onset typically occurs in childhood. No approved pharmacological treatments exist that halt or reverse disease progression. A novel flupirtine benzyl carbamate was orally administered to male and female Cln6nclf mice from 4 to 28 weeks of age to evaluate its neuroprotective and antispastic effects. Drug treatment produced significant, sex-dependent phenotypic improvements. Treated mice of both sexes exhibited reduced hindlimb spasticity, but only treated males demonstrated diminution in locomotor hyperactivity and recovery of visuospatial performance. In the brains of male and female Cln6nclf mice, flupirtine benzyl carbamate significantly decreased astrocytosis, microgliosis and mitochondrial ATP synthase subunit C (SCMAS) accumulation, increased neuronal marker expression and reduced the number of TUNEL-positive cells. The treatment failed to rescue photoreceptor loss or clear retinal SCMAS storage. These outcomes result in distinct sex-specific differences in neuronal vulnerability and drug responsiveness. Overall, these findings demonstrate that flupirtine benzyl carbamate diminishes key motor, visual and pathological deficits in CLN6 disease, highlighting its promise as a potential disease-modifying therapy for CLN6 in humans despite sex-specific differences.