Astragaloside IV ameliorates autism-like behaviors in BTBR mice by modulating Camk2n2-dependent OXPHOS and neurotransmission in the mPFC.

INTRODUCTION: Autism spectrum disorder (ASD) represents a multifaceted set of neurodevelopmental conditions marked by social deficits and repetitive behaviors. Astragaloside IV (ASIV), a natural compound derived from the traditional Chinese herb Astragali Radix, exhibits robust neuroprotective effects. However, whether ASIV can ameliorate behavioral deficits in ASD remains unknown. OBJECTIVES: This work aimed to determine the efficacy and molecular mechanisms of ASIV in ASD. METHODS: The autistic BTBR T + tf/J (BTBR) mice were used in this study. Behavioral tests were performed to assess the ASD-like phenotypes. The neurotransmitter levels and synaptic transmission were evaluated by high-performance liquid chromatography and whole-cell patch clamp recordings, respectively. Molecular biological techniques, immunostaining, and RNA-sequencing (RNA-seq) were combined to uncover the underlying molecular mechanisms. RESULTS: Our study showed that both social impairment and repetitive behaviors were significantly improved after ASIV treatment in a dose-dependent manner in BTBR mice. The ASIV treatment normalized the neurotransmitter levels (GABA and glutamate) and their corresponding vesicular transporters (vGAT, vGLUT1) in the medial prefrontal cortex (mPFC). Furthermore, the excitation-inhibition imbalance in layer V of mPFC was reversed after ASIV administration. Mechanistically, bulk RNA-seq and PPI network analysis identified Camk2n2 as the crucial bridging gene regulating oxidative phosphorylation and neurotransmission. Camk2n2 overexpression in the mPFC abolished the beneficial effects of ASIV on autistic symptoms in BTBR mice via the Camk2/CREB pathway. CONCLUSION: The evidence demonstrates that ASIV may become a promising treatment option for ASD and implies that targeting the Camk2n2/Camk2/CREB axis is warranted to investigate these ASD individuals further.