Prenatal Origins of Neurometabolic Consequences

 描述(申请人提供)：儿童发育迟缓的发生率占美国人口的18%，男孩多于女孩。环境因素(如胎儿发育异常和低血糖)和遗传异常在病因中起作用。发育迟缓和自闭症谱系障碍(ASDS)与拷贝数变异(CNV)、12号染色体上SLC2A3基因的缺失或复制有关。ASD是一种终生神经发育障碍(NDD)，伴有脑突触连接中断。SLC2A3基因翻译产物GLUT3蛋白是神经元促进性葡萄糖转运蛋白，为神经细胞增殖和分化、突触形成/可塑性和功能/神经传递所需的氧化代谢提供燃料。随着新的基因技术的出现，与CNV相关的表型明显的人类GLUT3缺乏症在儿童中被描述。我们先前观察到，在经典的单等位基因SLc2A3缺失伴胎儿生长受限(FGR)小鼠中，雄性小鼠表现出ASD症状。为了区分FGR对异常脑器官发生和疾病发生的影响，我们假设大脑皮层和海马神经元中缺乏GLUT3将揭示从自闭症到智能障碍的一种表型，从而揭开筛查和干预的可能性，即FGR可能有助于具有这些呈现特征的个体，并预防一些NDD及其相关的共病。为了验证这一假设，我们提出了以下特定的目标，通过干扰神经元特异性的Slc2A3在条件神经元GLUT3缺失小鼠系(Glu3loxP/loxP/nestinCre+)中，研究其对以下方面的影响：1.胎盘和胎儿脑中Slc2A3在不同孕期(G13、G19)的表达和功能；B.胎儿生长受限(FGR)对胎盘和胎儿脑中Slc2A3表达和功能的影响。2.出生后A.代谢状态，包括血浆、脑脊液和脑(神经元和神经胶质)代偿机制的代谢情况，B.脑形态和免疫组织化学检测不同细胞类型和过程中的异常。3.出生后和成人A.神经行为表型，包括活动、癫痫、认知、工作记忆、焦虑、社交、发声和刻板印象，B.膜片钳神经元检测功能损害的电生理学，以及生酮饮食逆转的可能性。我们的研究结果将使我们了解GLUT3缺乏对ASD的贡献和影响，为未来在多因素ASD/NDDS中检测GLUT3基因变异的内表型人类研究奠定基础。这将使后续的治疗发现成为可能。所获得的见解将可推广到预防和治疗与早期发育过程中遇到的神经元葡萄糖供应不足(例如FGR)有关的其他情况，并导致具有ASD临床特征的NDD，有时表现为脑电癫痫和婴儿小头畸形。

 DESCRIPTION (provided by applicant): The incidence of developmental delays in children is 18% of the US population, with boys outnumbering girls. Environmental factors (e.g. fetal growth deviations and hypoglycemia) and genetic aberrations play etiological roles. Developmental delays and autism spectrum disorders (ASDs) have been associated with copy number variations (CNVs), deletion or duplication of the Slc2A3 gene on chromosome 12. ASDs are life-long neurodevelopmental disorders (NDD) with brain synaptic disconnectivity. Slc2A3 gene translation product, Glut3 protein is the neuronal facilitative glucose transporter that fuels oxidative metabolism necessary for neural cell proliferation and differentiation, synaptic formation/plasticity and function/neurotransmission. The phenotypically distinct human GLUT3 deficiency associated with CNVs is being described in children with the advent of newer genetic technologies. We previously observed that in the classical mono-allelic Slc2A3 deletion mouse with fetal growth restriction (FGR), males expressed ASD symptoms. To separate the impact of FGR on aberrant brain organogenesis and the advent of morbidities, we hypothesize that lack of Glut3 in cerebral cortical and hippocampal neurons will reveal a phenotype ranging from autism to intellectual disability, thereby unraveling possibilities for screening and interventions, that an aid individuals with these presenting features and prevent some NDDs and their associated co-morbidities. To test this hypothesis, we propose the following specific aims by disrupting neuron-specific Slc2A3 in a conditional neuronal glut3 null deletion mouse line (glut3loxP/loxP/nestinCre+), to study the impact on: 1. a. Placental and fetal brain Slc2A3 expression and function at different gestational stages (G13, G19) and b. the role of fetal growth restriction (FGR) on placental and fetal brain Slc2A3 expression and function. 2. Postnatal a. metabolic status which includes plasma, cerebro-spinal fluid and brain (neuronal and glial) metabolic profile with compensatory mechanisms, b. brain morphology and immunohistochemistry to detect different cell types and aberrations in processes. 3. Postnatal and adult a. neurobehavioral phenotype including activity, seizures, cognition, working memory, anxiety, socialization, vocalization and stereotypies, with b. electrophysiology in patch-clamped neurons to detect functional impairments, and possibility of reversal with a ketogenic diet. The results of our proposed studies will inform us about the contribution and impact of glut3 deficiency on ASDs, setting the stage for future endophenotype human studies in detecting glut3 gene variations in the multifactorial ASD/NDDs. This will enable subsequent therapeutic discovery. The insights gained will be generalizable in preventing and treating other conditions related to deficient neuronal glucose supply (e.g. FGR) encountered during early development and resulting in NDDs with clinical features of ASDs, sometimes presenting with EEG seizures and infantile microcephaly.