Fluconazole reverses SHANK3-related autism-like deficits via lipid raft-driven IGF1R activation and prefrontal circuit remodeling

Autism spectrum disorder (ASD) is a neurodevelopmental condition that affects approximately 61.8 million people globally1. Mutations in the postsynaptic scaffolding protein SHANK3 define a high-penetrance ASD subgroup characterized by excitatory synaptic dysfunction2,3, yet disease-modifying therapies are lacking. Although transient IGF1 application ameliorates synaptic defects in Shank3-deficient models4, strategies for sustained activation of IGF1 receptor (IGF1R) signaling remain elusive. Here, we repositioned the FDA-approved antifungal agent fluconazole?5 as an effective therapy for SHANK3-related ASD. In Shank3-deficient mice, fluconazole restored social deficits and repetitive behaviors through remodeling postsynaptic scaffold proteins. Mechanistically, fluconazole promoted lipid raft assembly to drive IGF1R homodimerization and activation, triggering ERK-mediated antioxidant responses to restore synaptic architecture, evidenced by Homer1/PSD95 re-colocalization. Integrated single-cell/nucleus RNA sequencing revealed fluconazole-induced prefrontal circuit remodeling, involving expansion of Homer1? glutamatergic neurons and enhanced VIP? GABAergic interneuron function. Fluconazole specifically potentiated communication from VIP? interneurons to synapse-proficient glutamatergic neurons, leading to the restoration of postsynaptic ultrastructure in deep-layer prefrontal cortex. This reconfigured network induced by fluconazole supported a sustained recovery through a self-reinforcing IGF1-IGF1R-ERK signaling loop, with VIP? interneurons serving as a potential IGF1 source. Collectively, our findings establish fluconazole as a clinically translatable therapy for SHANK3-related ASD via IGF1R-driven synaptic remodeling. Overall design: This study administered fluconazole orally to Shank3-/- mice via drinking water for two weeks. The mice were divided into two groups: SHANK3 KO MOCK (vehicle control) and SHANK3 KO Flu (fluconazole-treated). After the treatment period, the mice were euthanized by cervical dislocation, and fresh prefrontal cortex tissue was rapidly dissected for subsequent combined single-cell and single-nucleus RNA sequencing (sc/sn-RNA-seq).