Glycerol Kinase Deficiency to Study Metabolic Diseases

描述（由申请人提供）：这些研究的长期目标是了解单基因疾病（甘油激酶缺乏症）如何导致复杂表型疾病的细胞机制。甘油激酶（Glycerol kinase， GK）催化甘油磷酸化生成甘油3-磷酸，处于葡萄糖和脂肪代谢的界面。甘油激酶缺乏症（GKD）是一种由甘油激酶基因（GK）突变和/或缺失引起的x连锁代谢紊乱。GKD患者表现为有症状或无症状。我们对甘油激酶缺乏症的初步研究表明，没有办法通过GK活性或蛋白质三维结构模型中突变的位置来预测哪些患者会有症状，哪些患者会无症状。我们假设GK突变与代谢通量（相关途径中的其他酶和关键中间体的水平）的其他遗传和环境影响的相互作用对理解这种疾病的发病机制很重要。

DESCRIPTION (provided by applicant): The long-term objectives of these investigations are to understand the cellular mechanisms of how a single gene disorder (glycerol kinase deficiency) causes a complex phenotypic disease. Glycerol kinase (GK) catalyzes the phosphorylation of glycerol into glycerol 3-phosphate and is at the interface of glucose and fat metabolism. Glycerol kinase deficiency (GKD) is an X-linked disorder of metabolism that is due to mutations and/or deletions of the glycerol kinase gene (GK). Patients with GKD are phenotypically either symptomatic or asymptomatic. Our initial work on glycerol kinase deficiency has shown that there is no way to predict which patients will be symptomatic and which will be asymptomatic by GK activity or the location of the mutation in a model of the three dimensional structure of the protein. We hypothesize that it is the interaction of GK mutations with additional genetic and environmental influences on metabolic flux (other enzymes in related pathways and levels of critical intermediates) that are important to understand the pathogenesis of this disorder. The goals of this proposal are to understand better the complex interactions within the cell and how perturbations of an individual enzyme (GK) affects the other pathways and gene expression to result in the physiological changes seen in the whole animal. Our first Specific Aim (Task 1) is to characterize the metabolic pathways relating to GK and how they are changed in GKD using lymphoblastoid cells lines from the individuals with GKD as well as normal individuals. Metabolome analysis, flux analysis, and transcriptome analysis will allow us to investigate the effect of the mutations with varying levels of GK activity in the context of the individuals' genetic background. We will then investigate the effect of these mutations in liver and kidney cell lines as these tissues have the highest level of GK expression and will allow us to investigate the role of the GK mutations within the context of identical genetic background. Results of these studies will allow us to perform metabolome, flux, and transcriptome analysis in the whole animal model using the glycerol kinase knock-out (gyk k/o) mouse (Specific Aim/Task 2). These studies will provide a model system to understand the complex nature of genetic disorders and eventually help in treatment of such disorders.