Cytoplasm-predominant Pten associates with increased region-specific brain tyrosine hydroxylase and dopamine D2 receptors in mouse model with autistic traits.
Cytoplasm-predominant Pten associates with increased region-specific brain tyrosine hydroxylase and dopamine D2 receptors in mouse model with autistic traits.
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DOI：
10.1186/s13229-015-0056-6
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发表时间：
2015
期刊：
影响因子：
6.2
通讯作者：
Eng C
中科院分区：
文献类型：
--
作者：
He X;Thacker S;Romigh T;Yu Q;Frazier TW Jr;Eng C
自闭症谱系障碍（ASD）是一组神经发育障碍，其特征在于社交/互动障碍和僵硬/重复行为。几条证据支持遗传因素是ASD的主要原因。在已经确定的自闭症易感基因中，PTEN肿瘤抑制基因，最初被确定为易患考登遗传性癌症综合征，被发现在患有极端大头畸形的ASD患者中发生突变。然而，介导PTEN突变效应的ASD相关分子机制仍然难以捉摸。我们开发了一种Pten基因敲入小鼠模型来研究Pten种系突变的影响，特别是改变ASD的亚细胞定位。从雄性同窝仔的半球中分离蛋白质，并进行蛋白质印迹以确定酪氨酸羟化酶（TH）的蛋白质表达水平。免疫组织化学染色证实TH和多巴胺D2受体（D2 R）的定位。然后比较异位表达野生型或错义突变体PTEN的PC 12细胞TH表达的差异。携带Pten突变的小鼠在纹状体和前额叶皮质中具有高TH和D2 R。它们还增加了cAMP反应元件结合蛋白（CREB）和TH的磷酸化。在机制上，PTEN通过抑制磷酸肌醇3-激酶（PI 3 K）/CREB信号通路下调PC 12细胞中TH的产生，而PTEN通过抑制MAPK通路减少TH磷酸化。与野生型PTEN不同，但与小鼠敲入突变体Pten相似，我们先前在ASD患者中鉴定的三种天然存在的PTEN错义突变，H93 R，F241 S和D252 G，在PC 12细胞中过表达时不能抑制TH。此外，另外两个PTEN错义突变，C124 S（泛磷酸酶死亡）和G129 E（脂质磷酸酶死亡），未能抑制TH时，异位表达在PC 12细胞。我们的数据揭示了大脑中的非经典PTEN-TH通路，其可能作为多巴胺信号传导的核心调节器工作，当功能障碍时，其在ASD中是致病的。本文的在线版本（doi：10.1186/s13229-015-0056-6）包含补充材料，可供授权用户使用。
Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders characterized by impairment in social communication/interaction and inflexible/repetitive behavior. Several lines of evidence support genetic factors as a predominant cause of ASD. Among those autism susceptibility genes that have been identified, the PTEN tumor suppressor gene, initially identified as predisposing to Cowden heritable cancer syndrome, was found to be mutated in a subset of ASD patients with extreme macrocephaly. However, the ASD-relevant molecular mechanism mediating the effect of PTEN mutations remains elusive. We developed a Pten knock-in murine model to study the effects of Pten germline mutations, specifically altering subcellular localization, in ASD. Proteins were isolated from the hemispheres of the male littermates, and Western blots were performed to determine protein expression levels of tyrosine hydroxylase (TH). Immunohistochemical stains were carried out to validate the localization of TH and dopamine D2 receptors (D2R). PC12 cells ectopically expressing either wild-type or missense mutant PTEN were then compared for the differences in TH expression. Mice carrying Pten mutations have high TH and D2R in the striatum and prefrontal cortex. They also have increased phosphorylation of cAMP response element-binding protein (CREB) and TH. Mechanistically, PTEN downregulates TH production in PC12 cells via inhibiting the phosphoinositide 3-kinase (PI3K)/CREB signaling pathway, while PTEN reduces TH phosphorylation via suppressing MAPK pathway. Unlike wild-type PTEN but similar to the mouse knock-in mutant Pten, three naturally occurring missense mutations of PTEN that we previously identified in ASD patients, H93R, F241S, and D252G, were not able to suppress TH when overexpressed in PC12 cells. In addition, two other PTEN missense mutations, C124S (pan phosphatase dead) and G129E (lipid phosphatase dead), failed to suppress TH when ectopically expressed in PC12 cells. Our data reveal a non-canonical PTEN-TH pathway in the brain that may work as a core regulator of dopamine signaling, which when dysfunctional is pathogenic in ASD. The online version of this article (doi:10.1186/s13229-015-0056-6) contains supplementary material, which is available to authorized users.