A novel rat model harboring two BDNF gene mutations exhibiting autism-like behaviors and cognitive impairments

Autism spectrum disorder (ASD) is a type of neurodevelopmental disorder that occurs most frequently in early childhood, affecting approximately 1% of the global population. Currently, the elusive nature of the pathological mechanisms underlying ASD precludes the existence of a definitive, effective treatment approach. In this study, we have successfully generated a novel ASD rat model utilizing CRISPR/Cas9 technology, offering a promising platform for further investigation and potential therapeutic interventions. The model is characterized by two crucial point mutations occurring at key enzyme cleavage sites of brain-derived neurotrophic factor (BDNF), thereby causing disruptions in enzyme cleavage processes. The phenotypes of this rat model faithfully recapitulate the salient deficits frequently encountered in ASD patients, exhibiting impairments in social behavior, cognition, and anxiety, along with neuronal abnormalities with key brain regions, notably the hippocampus (HPC) and medial prefrontal cortex (mPFC). Through preliminary RNA-seq analysis, we found changes in gene expression patterns related to synapses and neuronal excitability in these areas, providing new insights into the pathogenesis of ASD. Furthermore, our utilization of 7,8-dihydroxyflavone (7,8-DHF), a robust enhancer for the upregulation of both BDNF and TrkB mRNA and simultaneously activates the BDNF-TrkB signaling pathway, appears to strengthen the BDNF-TrkB signaling cascade. This intervention modifies firing patterns of neuronal spikes and synaptic transmission, which may contribute to the amelioration of ASD-like social interaction behavior exhibited in BDNF^met/leu rats. Our research not only deepens our understanding of the pathogenesis of ASD, but also present encouraging avenue for early intervention strategies and treatments.