Brain Abnormalities and Neurobehavioral Deficits in Hypoplastic Left Heart Syndrome

项目摘要 左心发育不良综合征（HLHS）是一种严重的先天性心脏病（CHD）， 治疗神经发育障碍事实上，超过30%的HLHS幸存者经历了中度至重度的 神经认知障碍虽然HLHS患者的大脑异常通常被认为是继发于 循环障碍导致的底物递送缺陷，我们最近恢复了HLHS突变小鼠的脑 这些异常指出了心脏缺陷和神经发育障碍的共同遗传病因。 这一点得到了其他研究的支持，这些研究显示CHD患者的染色质修饰基因发生了新生突变。 患神经发育障碍的风险增加，包括认知、运动、社交和语言障碍 损伤我们观察到HLHS突变小鼠的大脑异常，涉及皮层，海马， 和嗅球，前脑结构也经常在HLHS患者中受到影响。我们展示了HLHS和大脑 Ohia小鼠系中的异常具有双基因病因学，由两个基因的突变引起：Sin 3a- 相关蛋白130（Sap 130），一种介导转录抑制的染色质修饰蛋白，和 原钙粘蛋白a9（Pcdha 9），一种参与细胞-细胞粘附的蛋白质。由于染色质修饰基因已经 与自闭症有关，也与CHD患者的神经发育障碍有关，深入了解Sap 130的作用 在Ohia HLHS小鼠的大脑缺陷中， CHD和非CHD患者的神经发育结局。在这项研究中，我们将探讨假设 缺乏Sap 130会扰乱大脑发育，导致大脑发育不良，神经网络发生改变 连接和神经行为缺陷。在目标1中，我们将研究细胞和分子机制 导致大脑发育不良，集中在前脑。这将需要检查神经发生和皮质 平板形成并使用RNAseq和ChIPseq分析进行分子谱分析。在目标2中，我们将 多模态结构磁共振成像（MRI），包括扩散张量成像（DTI）， 表征前脑发育不良和神经网络连接变化有助于大脑 发育不良缺陷为了确定行为缺陷是否可能由大脑发育不良和神经系统疾病引起， 网络连接干扰，在目标3中，我们将进行一系列啮齿动物神经行为评估。 目的2和3中的研究将使用具有前脑靶向Cre介导的floxed Sap 130等位基因进行。 Sap 130缺失。这将使突变小鼠在没有心脏缺陷的情况下存活至成年。这样的老鼠将是 产生有或没有Pcdha 9突变，允许确定Pcdha 9在脑中的作用 异常这些研究将为HLHS的发育病因学提供新的见解 相关的大脑异常，以及神经结构的特定变化是否可能驱动相关的 神经行为/神经认知障碍。这些发现可能会成为未来小说发展的基础 可以实质性改善这一脆弱CHD人群的结局的治疗。

PROJECT SUMMARY Hypoplastic left heart syndrome (HLHS), a severe congenital heart disease (CHD), is associated with high risk for neurodevelopmental disabilities. In fact, over 30% of HLHS survivors experience moderate to severe neurocognitive impairment. While brain abnormalities in HLHS patients are typically thought to be secondary to substrate delivery deficits from circulatory disturbance, our recent recovery of HLHS mutant mice with brain abnormalities point to a shared genetic etiology for the heart defects and the neurodevelopmental disabilities. This is supported by other studies showing CHD patients with de novo mutations in chromatin modifying genes are at increased risk for neurodevelopmental disorders that can include cognitive, motor, social and language impairments. We observed HLHS mutant mice to have brain abnormalities involving the cortex, hippocampus, and olfactory bulb, forebrain structures also frequently affected in HLHS patients. We showed HLHS and brain abnormalities in the Ohia mouse line have a digenic etiology, arising from mutations in two genes: Sin3a- associated protein 130 (Sap130), a chromatin modifying protein mediating transcriptional repression, and protocadherin a9 (Pcdha9), a protein involved in cell-cell adhesion. As chromatin modifying genes are already implicated in autism and also in neurodevelopmental impairment in CHD patients, insights into the role of Sap130 in the brain defects of the Ohia HLHS mice will have broad relevance for understanding the causes for poor neurodevelopmental outcomes in CHD and non-CHD patients. In this study, we will investigate the hypothesis that Sap130 deficiency perturbs brain development, causing brain dysmaturation with altered neural network connectivity and neurobehavioral deficits. In Aim 1, we will investigate the cellular and molecular mechanisms driving the brain dysmaturation, focusing on the forebrain. This will entail examining neurogenesis and cortical plate formation and conducting molecular profiling with RNAseq and ChIPseq analyses. In Aim 2, we will conduct multi-modal structural magnetic resonance imaging (MRI) that will include diffusion tensor imaging (DTI) to characterize the forebrain dysplasia and neural network connectivity changes contributing to the brain dysmaturation defects. To determine if behavioral defects may be elicited by the brain dysmaturation and neural network connectivity perturbations, in Aim 3 we will conduct a battery of rodent neurobehavioral assessments. The studies in Aims 2 and 3 will be carried out using a floxed Sap130 allele with forebrain targeted Cre mediated Sap130 deletion. This will allow mutant mice to survive to adulthood without heart defects. Such mice will be generated with or without the Pcdha9 mutation, allowing determination of the role of Pcdha9 in the brain abnormalities. Together these studies will yield new insights into the developmental etiology of the HLHS associated brain abnormalities and whether specific changes in neural architecture may drive the associated neurobehavioral/neurocognitive impairments. These findings may form the basis for future development of novel therapeutics that can substantively improve outcome for this vulnerable CHD population.