CNTN4参与神经发育和精神疾病发生的分子机制研究

Psychiatric disorders, such as autism and bipolar disorder, are common illnesses that seriously affect human health. Neural cell adhesion molecules play an important role in the pathogenesis of these disorders. We previously identified two Chinese subjects with autism with copy number variations that disrupt Contactin 4 (CNTN4). We further demonstrated that CNTN4 was exclusively expressed in the brain, especially in the prefrontal cortex. We made CNTN4 knockout (CNTN4-/-) mice and found that CNTN4-/- mice showed reduced anxiety-like behaviors in open field, light dark box and elevated plus maze tests; CNTN4-/- mice also showed reduced depression-like behaviors in forced swimming and tail suspension tests. The expression of AMPAR subunit GluR1 in the prefrontal cortex was reduced in CNTN4-/- mice, and CNTN4-/- mice had less mature spines in layer II/III pyramidal cells (PCs) of the prefrontal cortex. The mEPSC frequency and amplitude in PCs of the prefrontal cortex was reduced in CNTN4-/- mice. Based on these results, we postulate that CNTN4 was involved in synaptogenesis and neural development, regulating the pathogenesis of psychiatric disorders. We propose to clarify the function of CNTN4 in neural development and the molecular mechanism of CNTN4 in the pathogenesis of psychiatric disorders. Our study could potentially provide new insights into the treatment of psychiatric disorders by offering new molecular mechanism in psychiatric disorders.

孤独症、双相情感障碍等精神疾病严重危害人类健康，神经黏附分子在精神疾病的发生中有着重要作用。申请人前期研究发现两个孤独症患者同时存在打断CNTN4基因的CNV；构建CNTN4基因敲除鼠进一步研究发现：CNTN4特异性表达于脑组织中并在皮层中具有较高表达；CNTN4-/-小鼠在开场实验、明暗箱实验以及高架十字迷宫中都表现出焦虑降低；在强迫游泳、悬尾实验中表现出抑郁降低；CNTN4-/-小鼠前额叶皮层中GluR1的表达较WT小鼠降低，成熟树突棘数量较WT小鼠减少，前额叶皮层II-III层的mEPSC频率和幅度降低。我们认为CNTN4可能通过参与突触的形成及神经发育，调控精神疾病的发生。本研究拟进一步利用细胞模型、CNTN4基因敲除小鼠和转基因小鼠等，阐明该基因在神经发育中的功能和导致精神疾病的分子机制。本研究将为精神疾病的诊疗提供潜在靶点及理论依据。

接触蛋白-4（contactin-4，CNTN4）是一个重要的神经粘附分子，但其在神经元发育过程中的作用仍知之甚少。本课题利用神经元等细胞模型、基因敲除小鼠以及转基因小鼠等动物模型，发现：CNTN4不能促进神经元自身的轴突生长；CNTN4分布在树突、促进树突生长并促进树突棘的发生，但不影响树突棘的成熟过程；兴奋性/抑制性平衡依赖于CNTN4的表达量；CNTN4可改变神经元的钙瞬变频率。CNTN4对神经元树突棘的影响依赖其膜定位和FNⅢs结构域，CNTN4与淀粉样蛋白前体蛋白APP的相互作用影响树突棘发生。分析了4个自闭症相关的CNTN4突变，发现p.N178D，p.G221D和p.E331G等3个突变体不能促进树突棘生长和钙瞬变频率。课题初步阐明了CNTN4基因参与神经发育、调控自闭症等精神疾病发生的分子机制。