Delineating contributions of PI3K signaling to neurodevelopmental consequences of Pten haploinsufficiency

项目摘要/摘要 自闭症谱系障碍(ASD)是一种非常不同的疾病集合，这些疾病汇聚在 社交和沟通困难的症状，以及兴趣受限和重复的行为。 这种异质性的背后可能有多种原因。因此，近年来已经变得明显的是， “一刀切”的方法治疗ASD是不够的。相反，根据特定情况对个人进行分层 风险因素和症状正越来越多地被探索为开发有针对性的个性化治疗的一种方式 对于ASD。在这方面受到极大关注的一个危险因素是PTEN基因的突变， 它编码了发育中的身体和大脑生长的关键调节因素。种系杂合突变 在这个基因中，通常会降低PTEN蛋白的水平，在ASD和 巨头畸形(头部和大脑过度生长)。我们的实验室已经证明，携带等价物的小鼠 Pten基因的突变既显示了大脑过度生长，也显示了社会行为缺陷，建立了 PTEN蛋白水平足以在动物模型中引起ASD相关症状。PTEN编码一个 作为磷脂酰肌醇3-激酶(PI3K)的负调节因子的磷酸酶，以及 PI3K-Akt-mTor通路的失调与神经发育病理生物学有关 ASD的临床前模型的多样性。人们对mTOR的抑制给予了很大的关注，尤其是 MTOR复合体1(MTORC1)作为治疗神经发育表型的策略 PTEN和PI3K-Akt-mTOR途径的其他调节因子的突变。相比之下，治疗潜力 对PI3K抑制的研究还不充分，还没有在Pten的体内临床前模型中进行验证 单倍体功能不全。该项目旨在解决这一问题，并描述PI3K的贡献 Pten单倍体功能不全导致的神经发育表型信号。我们最重要的是 假说是，在发育过程中通过抑制PI3K来治疗PTEN+/-小鼠将挽救与ASD相关的疾病 通过正常化下游信号的表型。这项提议的两个目标将检验这一假设 通过对PIK3CA；Pten复合突变小鼠PI3K的遗传抑制(目标1)和对Pten的治疗 在发育过程中不同的时间窗使用药物PI3K抑制剂的单倍体不足小鼠 确定治疗的关键时期(目标2)。对于这两个目标，与ASD相关的健壮和可重现 Pten单倍体缺陷小鼠的神经解剖学和行为表型将被用作读数。 这项工作的主要成果将包括PI3K抑制作为一种潜在的治疗方法的临床前测试 纠正PTEN突变的神经发育后果和确定一个关键期 当治疗可能导致ASD相关症状被抑制时。

Project Summary/Abstract Autism spectrum disorder (ASD) is a remarkably heterogeneous collection of conditions that converge on the symptoms of social and communication difficulties, together with restricted interests and repetitive behavior. Underlying this heterogeneity is likely a variety of etiologies. Thus, it has become clear in recent years that a “one-size-fits-all” approach to treating ASD is not sufficient. Rather, stratifying individuals based on particular risk factors and symptoms is increasingly being explored as a way to develop targeted personalized treatments for ASD. One risk factor that is receiving significant attention in this context is mutations in the gene PTEN, which encodes a key regulator of growth in the developing body and brain. Germline heterozygous mutations in this gene, which generally reduce levels of PTEN protein, are common in individuals with ASD and macrocephaly (overgrowth of the head and brain). Our laboratory has shown that mice carrying equivalent mutations in Pten display both brain overgrowth and social behavioral deficits, establishing that a reduction in Pten protein level is sufficient to cause ASD-relevant symptoms in an animal model. Pten encodes a phosphatase that acts as a negative regulator of the enzyme phosphoinositide 3-kinase (PI3K), and dysregulation of the PI3K-Akt-mTOR pathway has been linked with neurodevelopmental pathobiology across a variety of preclinical models of ASD. Much attention has been given to inhibition of mTOR, and in particular mTOR complex 1 (mTORC1), as a strategy for treating the neurodevelopmental phenotypes arising from mutations in PTEN and other regulators of the PI3K-Akt-mTOR pathway. In contrast, the therapeutic potential of PI3K inhibition is underexplored, and has not been tested in validated in vivo preclinical models of Pten haploinsufficiency. This project aims to address this problem and to delineate the contributions of PI3K signaling to neurodevelopmental phenotypes resulting from Pten haploinsufficiency. Our overarching hypothesis is that treatment of Pten+/- mice via PI3K inhibition during development will rescue ASD-relevant phenotypes by normalizing downstream signaling. The two aims of this proposal will test this hypothesis through genetic suppression of PI3K in Pik3ca; Pten compound mutant mice (Aim 1) and through treating Pten haploinsufficient mice with a pharmacological PI3K inhibitor at distinct time windows during development to identify a critical period for treatment (Aim 2). For both aims, robust and reproducible ASD-relevant neuroanatomical and behavioral phenotypes in Pten haploinsufficient mice will be used as readouts. Key outcomes of this work will include preclinical testing of PI3K inhibition as a potential therapeutic approach to correct the neurodevelopmental consequences of PTEN mutations and the identification of a critical period when treatment may lead to a suppression of ASD-relevant symptoms.