吻侧岛叶―边缘前皮质通路调控自闭症模型小鼠社交行为及其机制研究

Autism is an inherited, multivariate neurological developmental disorder. The world health organization has officially declared that social behavior disorder is one of its typical symptom. Previous studies have shown that the insular cortex and medial prefrontal cortex are involved in regulating the social behavior of the organism, and there are neuronal interconnections between each other. However, It is not clear whether there is a functional link between the insular cortex and the medial prefrontal cortex, which are both involved in regulating social behavior. In this study, we boldly speculated that the functional connectivity of the insular cortex and medial prefrontal cortex plays an important role in regulating autism social behavior disorder. To this end, we first investigate the detailed loop connection of the insular cortex and the medial prefrontal cortex subregion using the stereotactic microinjection and virus tracing technique. Then, the changes of basic electrophysiological properties, synaptic transmission and synaptic plasticity in the insular and the medial prefrontal cortex subregion are elucidated by the technique of patch clamp recording. Combined with the mouse social behavior model and the fiber optometry technology, the activity patterns and changes of the insular and medial prefrontal cortex subregion are observed in real time. Finally, the precise manipulation and improvement of the social behavior deficiency of autism model mice are realized by chemogenetics. We expect that our work will provide paradigms for clinical research and treatment of social defects in autistic patients.

自闭症是一种遗传性、多样性神经系统发育障碍性疾病。世界卫生组织官方宣布社交行为学障碍是其典型症状。前期研究表明，岛叶皮层及内侧前额叶皮层亚区都参与调控机体社交行为过程，且两者之间存在解剖学联系，但目前关于岛叶-内侧前额叶皮层神经环路的精准联系及其在调控社交行为中的作用机制仍不甚明了。为此在本研究中，我们拟结合立体定向微量注射与病毒示踪技术，首先解析岛叶与内侧前额叶皮层亚区的精细连接环路。其次，利用脑片膜片钳技术系统阐明自闭症模型小鼠岛叶-内侧前额叶皮层环路的基本电生理特征与突触可塑性变化特点。我们还将借助小鼠社交与共情行为学范式，结合光纤记录技术，实时解析MeCP2转基因自闭症模型小鼠岛叶-内侧前额叶环路特定类型神经元活动的变化规律。最后，结合化学遗传学等技术手段，探讨对自闭症模型小鼠社交与共情行为的精准操控，以期为理解自闭症行为障碍的神经机制和临床干预治疗提供实验依据和理论支撑。

自闭症是一种遗传性、多样性神经系统发育障碍性疾病。世界卫生组织官方宣布社交行为学障碍是其核心症状。我们采用MeCP2-Tg自闭症模型小鼠，发现其相比于正常鼠表现出喜新厌旧的行为缺陷。本研究主要采用病毒标记技术、微型在体双光子成像，结合化学遗传学、CRISPR-Cas9技术阐明正常小鼠社交行为喜新厌旧的生理机制及自闭症模型小鼠喜新厌旧行为缺陷的病理机制。我们成功建立自由活动小鼠在体双光子成像技术，我们发现：1）相比于兴奋性神经元，前边缘皮质中间能神经元与小鼠社交行为更相关，2）使前边缘皮质中间神经元MECP2蛋白表达正常化即能改善自闭鼠喜新厌旧社交行为缺陷的表型，这为临床治疗指明了方向，3）神经元信号解码分析发现由于编码新旧属性的神经元兴奋模式异常导致自闭症鼠喜新厌旧行为缺陷。相应工作已经投稿至PNAS杂志。另外，我们还发现揭示MeCP2 T203M 位点突变致自闭症及神经发育相关疾病的机制。破坏MeCP2的O-GlcNAcylation，特别是在T203处，会损害培养的海马神经元的树突发育和棘突成熟，破坏神经元迁移、树突棘突的形态发生。脑片膜片钳实验结果证明T203M会导致发育中的幼年小鼠大脑皮层的突触传递功能障碍。MeCP2上T203的O-GlcNA酰化中断减少了神经元活动诱导的Bdnf转录。这对理解MECP2突变引起的RTT的神经病理学背后的分子机制至关重要。相应成果以封面论文发表在中国神经科学会会刊Neuroscience bulletin。另外在项目资助下还发表中文论文一篇，获发明专利授权一项、实用新型专利授权一项。