Synaptic abnormalities and cytoplasmic glutamate receptor aggregates in contactin associated protein-like 2/Caspr2 knockout neurons
Synaptic abnormalities and cytoplasmic glutamate receptor aggregates in contactin associated protein-like 2/Caspr2 knockout neurons
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DOI：
10.1073/pnas.1423205112
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发表时间：
2015-05-12
影响因子：
11.1
通讯作者：
Penzes, Peter
中科院分区：
文献类型：
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作者：
Varea, Olga;Martin-de-Saavedra, Maria Dolores;Penzes, Peter
中枢神经元突触和控制它们的分子通路正在成为精神障碍发病机制中的常见底物。接触蛋白相关蛋白样2（CNTNAP 2）基因的遗传变异，包括拷贝数变异、外显子缺失、截短、单核苷酸变异和多态性，与智力残疾、癫痫、精神分裂症、语言障碍和自闭症相关。CNTNAP 2由Cntnap 2编码，是树突棘发育所必需的，其缺失导致小鼠疾病相关表型。然而，CNTNAP 2调节神经元突触的机制尚不清楚，并且尚未在Cntnap 2敲除神经元中研究细胞表型。在这里，我们表明CNTNAP 2存在于树突棘，以及轴突和索马。结构照明超分辨率显微镜揭示更接近兴奋性，而不是抑制性突触标记。CNTNAP 2不促进突触的形成，并且来自Cntnap 2敲除小鼠的培养的神经元不显示轴突和树突生长的早期缺陷，这表明CNTNAP 2在该阶段不需要。然而，来自敲除小鼠的成熟神经元显示棘密度和棘中AMPA受体的GluA1亚基水平降低。出乎意料的是，敲除的神经元显示GluA1的大细胞质聚集体。在这里，我们的特点，第一次我们的知识，Cntnap2敲除神经元的突触表型，并揭示了一个新的作用CNTNAP 2在GluA1贩运。总之，我们的研究结果提供了深入了解CNTNAP 2的生物学作用和CNTNAP 2相关神经精神疾病的发病机制。
Central glutamatergic synapses and the molecular pathways that control them are emerging as common substrates in the pathogenesis of mental disorders. Genetic variation in the contactin associated protein-like 2 (CNTNAP2) gene, including copy number variations, exon deletions, truncations, single nucleotide variants, and polymorphisms have been associated with intellectual disability, epilepsy, schizophrenia, language disorders, and autism. CNTNAP2, encoded by Cntnap2, is required for dendritic spine development and its absence causes disease-related phenotypes in mice. However, the mechanisms whereby CNTNAP2 regulates glutamatergic synapses are not known, and cellular phenotypes have not been investigated in Cntnap2 knockout neurons. Here we show that CNTNAP2 is present in dendritic spines, as well as axons and soma. Structured illumination superresolution microscopy reveals closer proximity to excitatory, rather than inhibitory synaptic markers. CNTNAP2 does not promote the formation of synapses and cultured neurons from Cntnap2 knockout mice do not show early defects in axon and dendrite outgrowth, suggesting that CNTNAP2 is not required at this stage. However, mature neurons from knockout mice show reduced spine density and levels of GluA1 subunits of AMPA receptors in spines. Unexpectedly, knockout neurons show large cytoplasmic aggregates of GluA1. Here we characterize, for the first time to our knowledge, synaptic phenotypes in Cntnap2 knockout neurons and reveal a novel role for CNTNAP2 in GluA1 trafficking. Taken together, our findings provide insight into the biological roles of CNTNAP2 and into the pathogenesis of CNTNAP2-associated neuropsychiatric disorders.