deptor disruption induces axonal and behavioral abnormalities through altered cholesterol metabolism in zebrafish

The mechanistic target of rapamycin (mTOR) signaling pathway is a highly conserved regulator of cellular growth and survival. DEPTOR serves as an endogenous inhibitor of this pathway by directly binding to both mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). While DEPTOR is extensively implicated in oncology and peripheral metabolism, its role in the nervous system remains poorly understood. In this study, we utilized CRISPR/Cas9 technology to disrupt deptor in the zebrafish model to investigate its neurodevelopmental functions. We found that deptor^-/- larvae exhibit motor deficits alongside structural axonal abnormalities, characterized by misaligned and broadened axonal tracts. These phenotypes were accompanied by the transcriptional dysregulation of key cholesterol-regulatory genes and progressive, aberrant accumulation of cholesterol from 5 to 10 days post-fertilization. Pharmacological elevation of cholesterol levels recapitulated these axonal and behavioral defects in wild-type larvae, whereas clearance of excess cholesterol successfully rescued the mutant phenotype. Together, our findings demonstrate that deptor deficiency drives cholesterol dysregulation, causing structural and functional abnormalities in the nervous system. This study uncovers a novel link between DEPTOR, lipid homeostasis, and neurodevelopment, highlighting cholesterol metabolism as a potential therapeutic target for neurological disorders associated with mTOR pathway dysfunction.