Genetic and Functional Mechanisms in Citrate Transporter Disorder associated with SLC13A5

与 SLC13A5 相关的柠檬酸转运蛋白紊乱的遗传和功能机制

基本信息

批准号：
10651203
负责人：
STEPHEN L HELFAND
金额：
$ 65.22万
依托单位：
BROWN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-06-01 至 2028-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10651203
关键词：
Affect Alleles Animal Diseases Animal Model Astrocytes Behavioral Symptoms Biological Assay Brain Cell membrane Cells Central Nervous System Citrates Code Complex Cytoplasm DNA Data Defect Development Disease Disease model Drosophila genus Electroencephalography Electrophysiology (science)Epilepsy Genes Genetic Genotype Human Human Genetics Immunohistochemistry Knock-out Knockout Mice Life Measures Metabolism Methods Missense Mutation Modeling Molecular Molecular Genetics Mus Mutation Nature Neurobehavioral Manifestations Neuronal Dysfunction Neurons Neurotransmitters Oligodendroglia Partial Epilepsies Pathogenicity Pathway interactions Patients Phenotype Physiological Physiology Plasma Point Mutation Proteins RNA Interference Recurrence Research Rodent Role Seizures Severities Slice Structure Syndrome System Techniques Testing Therapeutic Therapeutic Intervention Tissues Toxic effect autosome causal variant cell type cellular pathology citrate carrier design early onset epileptic encephalopathies epileptiform fly gain of function gene therapy genome editing individualized medicine interdisciplinary approach loss of function metabolomics motor symptom mouse genetics mouse model mutant neural circuit neurotransmitter metabolism novel novel therapeutic intervention patch clamp preclinical study recessive genetic trait reduce symptoms

项目摘要

Scientific Abstract: SLC13A5 epilepsy is a newly recognized form of Developmental Epileptic Encephalopathy 25 (DEE25) with seizures beginning within the first days of life along with subsequent intellectual and motor symptoms. In these patients, mutations in the SLC13A5 gene, which encodes a plasma membrane citrate transporter, result in a severe, early onset multi-focal epilepsy and cognitive and behavioral symptoms. How disruption of SLC13A5 function results in dysfunction of neural circuitry is unknown. In patients and in rodent loss of function models of SLC13A5, plasma citrate concentrations are elevated and cytoplasmic citrate is decreased. Since citrate is a precursor to neurotransmitters, diminished glial and neuronal citrate may result in abnormal neuro-transmitter metabolism, contributing to functional defects. However, SLC13A5 loss of function may not account for the full severity of the disorder, and truncations of SLC13A5 are rarely observed in patients. Instead, human genetics show that certain mutations are over-represented as known causative mutations; SLC13A5 G219R (DNA G655A) and T227M (DNA C680T) are the most common recurrent mutations found in approximately two-thirds of all known patients. While the epilepsy is associated with bi-alleleic mutations, the presence of recurrent missense mutations suggests mechanisms more complex than simple autosomal recessive genetics. However, these have not been fully investigated, and no specific treatments for these patients exist. In order to better understand the genetics of SLC13A5 epilepsy, we have developed novel experimental systems. In fly, the entire Drosophila Slc13A5 gene was replaced with the human SLC13A5 coding region. This results in expression of only the human SLC13A5 expressed in the central nervous system. In the humanized line, the G219R mutation causes lethality in contrast to the null, suggesting gain of function mechanisms. In rodents, we show that the equivalent mutation to G219R in mouse SLC13A5 causes more severe epilepsy in direct comparison to the null, again suggesting the over-arching hypothesis of this proposal: that pathogenic mutations in SLC13A5 have gain of function effects, as well as, loss of function effects. However, the understanding of the mechanisms underlying these effects is incomplete, and the determination of both genetic and functional mechanisms are highly important for developing treatments for SLC13A5 epilepsy. We will determine in three Aims to determine:1) what is the normal function of SLC13A5 in brain physiology 2) how do pathogenic mutations in SLC13A5 result in neural dysfunction 3) if novel therapeutic strategies may ameliorate symptoms in SLC13A5 syndrome.

科学摘要： SLC13A5 癫痫是一种新认识的发育性癫痫性脑病 25 (DEE25) 出生后几天内开始癫痫发作，并伴有随后的智力和运动症状。在这些患者的 SLC13A5 基因（编码质膜柠檬酸转运蛋白）发生突变严重的、早发的多灶性癫痫以及认知和行为症状。 SLC13A5如何中断神经回路功能障碍的结果尚不清楚。在患者和啮齿动物的功能丧失模型中 SLC13A5，血浆柠檬酸盐浓度升高，细胞质柠檬酸盐浓度降低。由于柠檬酸盐是作为神经递质的前体，神经胶质和神经元柠檬酸盐的减少可能会导致神经递质异常新陈代谢，导致功能缺陷。然而，SLC13A5 的功能丧失可能无法解释全部疾病的严重程度以及 SLC13A5 的截短很少在患者中观察到。相反，人类遗传学表明某些突变被过度描述为已知的致病突变； SLC13A5 G219R（DNA G655A) 和 T227M (DNA C680T) 是在大约三分之二的人中发现的最常见的复发突变所有已知患者。虽然癫痫与双等位基因突变有关，但复发性癫痫的存在错义突变表明机制比简单的常染色体隐性遗传更为复杂。然而，这些尚未得到充分研究，并且不存在针对这些患者的具体治疗方法。为了更好地了解 SLC13A5 癫痫的遗传学，我们开发了新的实验系统。在果蝇中，整个果蝇 Slc13A5 基因被人类 SLC13A5 编码区取代。这结果仅表达在中枢神经系统中表达的人类SLC13A5。在人性化的线，G219R 突变导致致死率，与无效突变相反，表明功能增强机制。在啮齿类动物中，我们发现小鼠 SLC13A5 中 G219R 的等效突变会导致更严重的癫痫与零值的直接比较，再次暗示了该提案的总体假设：致病性 SLC13A5 的突变具有功能获得效应和功能丧失效应。然而，对这些影响背后的机制的理解并不完整，并且遗传因素的确定功能机制对于开发 SLC13A5 癫痫的治疗方法非常重要。我们将确定三个目的确定：1）SLC13A5 在大脑生理学中的正常功能是什么 2）如何 SLC13A5 的致病突变导致神经功能障碍 3) 如果新的治疗策略可以改善 SLC13A5 综合征的症状。