Developmental Deficits of MGE-derived Interneurons in the Cntnap2 Knockout Mouse Model of Autism Spectrum Disorder

Interneurons are fundamental cells for maintaining the excitation-inhibition balance in the brain in health and disease. While interneurons have been shown to play a key role in the pathophysiology of autism spectrum disorder (ASD) in adult mice, little is known about how their maturation is altered in the developing striatum in ASD. Here, we aimed to track striatal developing interneurons and elucidate the molecular and physiological alterations in the Cntnap2 knockout mouse model. Using Stereo-seq and single-cell RNA sequencing data, we first characterized the pattern of expression of Cntnap2 in the adult brain and at embryonic stages in the medial ganglionic eminence (MGE), a transitory structure producing most cortical and striatal interneurons. We found that Cntnap2 is enriched in the striatum, compared to the cortex, particularly in the developing striatal cholinergic interneurons. We then revealed enhanced MGE-derived cell proliferation, followed by increased cell loss during the canonical window of developmental cell death in the Cntnap2 knockout mice. We uncovered specific cellular and molecular alterations in the developing Lhx6-expressing cholinergic interneurons of the striatum, which impacts interneuron firing properties during the first postnatal week. Overall, our work unveils some of the mechanisms underlying the shift in the developmental trajectory of striatal interneurons which greatly contribute to the ASD pathogenesis. control adult mouse brain中间神经元（Interneurons）是维持健康与疾病状态下大脑兴奋-抑制平衡的核心细胞。尽管已有研究证实，中间神经元在成年小鼠孤独症谱系障碍（ASD）的病理生理学过程中发挥关键作用，但目前对于孤独症谱系障碍个体发育中的纹状体里，中间神经元的成熟过程如何发生改变，仍知之甚少。本研究旨在追踪纹状体发育中的中间神经元，并阐明Cntnap2基因敲除（Cntnap2 knockout）小鼠模型中的分子与生理学改变。我们利用Stereo-seq与单细胞RNA测序（single-cell RNA sequencing）数据，首先对成年大脑以及内侧神经节隆起（MGE）胚胎阶段的Cntnap2表达模式进行了表征——内侧神经节隆起是产生绝大多数皮层与纹状体中间神经元的暂时性结构。我们发现，相较于大脑皮层，Cntnap2在纹状体中富集，尤其在发育中的纹状体胆碱能中间神经元中表达水平更高。随后我们揭示，Cntnap2基因敲除小鼠中，源自内侧神经节隆起的细胞增殖能力增强，且在发育性细胞死亡的典型窗口期内出现了细胞丢失增加的现象。我们还揭示了纹状体中表达Lhx6的发育性胆碱能中间神经元发生的特异性细胞与分子改变，这类改变会影响出生后第一周内中间神经元的放电特性。总体而言，本研究揭示了纹状体中间神经元发育轨迹偏移背后的部分机制，而该偏移极大地参与了孤独症谱系障碍的发病过程。对照成年小鼠大脑