背景:正常大脑发育的中断与许多神经发育起源的精神疾病有关,包括自闭症谱系障碍(ASD)。最近,由神经发育过程失调引起的大脑结构和功能的广泛异常已显示出跨代产生不利影响。兴奋性/抑制性(E/I)传递之间的不平衡是ASD发病机理的假定假设,抑制性γ-氨基丁酸(GABA)能系统在自闭症个体和ASD动物模型中的具体含义。然而,GABA能系统在ASD各代的神经病理生理学中的贡献仍然未知。这里,我们发现,在VPA诱导的ASD动物模型的世代中,杏仁核中GABAA受体(GABAAR)的表达和功能发生了深刻的变化。
方法:在F0中,在胚胎日(E12.5)单次注射VPA后,通过将F1VPA诱导的雄性后代与原始雌性交配产生F2代。通过动物行为测试评估自闭症样行为。使用蛋白质印迹和电生理技术检查了GABAAR和相关蛋白的表达和功能特性。
结果:社会赤字,重复行为,并在两代VPA诱导的后代中证明了情绪合并症。突触GABAAR和gephyrin水平降低,在两代VPA诱导的后代的杏仁核中发现了抑制性传播,F2代的减少更大。与F1代相比,F2代与GABAAR的结合更弱。此外,在VPA诱导的后代中,NMDA诱导的突触处的gephyrin和GABAAR的异常增强在F2代中比F1代恶化。在VPA诱导的后代的世代中还显示出升高的谷氨酸能修饰,而没有世代差异。
结论:综合来看,这些发现揭示了来自两代VPA诱导的后代的杏仁核中的E/I突触异常,提示GABA能系统对ASD代际病理生理学的潜在治疗作用。
BACKGROUND: Disruption of normal brain development is implicated in numerous psychiatric disorders with neurodevelopmental origins, including autism spectrum disorder (ASD). Widespread abnormalities in brain structure and functions caused by dysregulations of neurodevelopmental processes has been recently shown to exert adverse effects across generations. An imbalance between excitatory/inhibitory (E/I) transmission is the putative hypothesis of ASD pathogenesis, supporting by the specific implications of inhibitory γ-aminobutyric acid (GABA)ergic system in autistic individuals and animal models of ASD. However, the contribution of GABAergic system in the neuropathophysiology across generations of ASD is still unknown. Here, we uncover profound alterations in the expression and function of GABAA receptors (GABAARs) in the amygdala across generations of the VPA-induced animal model of ASD.
METHODS: The F2 generation was produced by mating an F1 VPA-induced male offspring with naïve females after a single injection of VPA on embryonic day (E12.5) in F0. Autism-like behaviors were assessed by animal behavior tests. Expression and functional properties of GABAARs and related proteins were examined by using western blotting and electrophysiological techniques.
RESULTS: Social deficit, repetitive behavior, and emotional comorbidities were demonstrated across two generations of the VPA-induced offspring. Decreased synaptic GABAAR and gephyrin levels, and inhibitory transmission were found in the amygdala from two generations of the VPA-induced offspring with greater reductions in the F2 generation. Weaker association of gephyrin with GABAAR was shown in the F2 generation than the F1 generation. Moreover, dysregulated NMDA-induced enhancements of gephyrin and GABAAR at the synapse in the VPA-induced offspring was worsened in the F2 generation than the F1 generation. Elevated glutamatergic modifications were additionally shown across generations of the VPA-induced offspring without generation difference.
CONCLUSIONS: Taken together, these findings revealed the E/I synaptic abnormalities in the amygdala from two generations of the VPA-induced offspring with GABAergic deteriorations in the F2 generation, suggesting a potential therapeutic role of the GABAergic system to generational pathophysiology of ASD.