Exploring therapeutic strategies for Infantile Neuronal Axonal Dystrophy (INAD/ <i>PARK14</i> )

Abstract Infantile Neuroaxonal Dystrophy (INAD) is caused by recessive variants in PLA2G6 and is a lethal pediatric neurodegenerative disorder. Loss of the Drosophila homolog of PLA2G6 , leads to ceramide accumulation, lysosome expansion, and mitochondrial defects. Here, we report that ceramide metabolism, the endolysosomal pathway, and mitochondrial morphology are affected in INAD patient-derived neurons. We show that in INAD mouse models the same features are affected and that glucosylceramides are elevated in dopaminergic neurons and Purkinje cells, arguing that the neuropathological mechanisms are evolutionary conserved and that ceramides can be used as biomarkers. We tested 20 drugs that target these pathways and found that Ambroxol, Desipramine, Azoramide, and Genistein alleviate neurodegenerative phenotypes in INAD flies and INAD patient-derived NPCs. We also develop an AAV-based gene therapy approach that delays neurodegeneration and prolongs lifespan in an INAD mouse model. One Sentence Summary Ceramide accumulation, lysosomal expansion and mitochondrial defects are a root cause of INAD/PARK14.