Adaptive Regulation of Vitamin B1 Transport

维生素 B1 运输的适应性调节

• 批准号: 8430562
• 负责人: Jason A Zastre
• 金额: $ 17.69万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-02 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8430562
• 关键词: Alcohol consumption; Alcohol dependence; Alcoholism; Alcohols; Attenuated; Bioenergetics; Biological Assay; Cells; Coenzymes; Country; Data; Developing Countries; Dietary intake; Disease; Disease Progression; Down-Regulation; Enzymes; Ethanol Metabolism; Future; Gene Expression; Gene Expression Regulation; Goals; Homeostasis; Human; Hypoxia; Impairment; Intestines; Kidney; Knowledge; Laboratories; Lactic Acidosis; Lead; Link; Luciferases; Malnutrition; Mediating; Metabolic; Metabolic stress; Metabolism; Mission; Neurologic; Nutritional; Outcome; Oxidative Stress; Pathology; Pathway interactions; Process; Promoter Regions; Public Health; Pyruvate; Regulation; Regulatory Element; Research; Response Elements; Stress; Testing; Thiamine; Thiamine Deficiency; Trans-Activators; Transcriptional Regulation; Transport Process; Up-Regulation; Work; absorption; base; chronic alcohol ingestion; hypoxia inducible factor 1; innovation; insight; mitochondrial dysfunction; nutrition; promoter; public health relevance; transcription factor; uptake

DESCRIPTION (provided by applicant): Vitamin B1 (thiamine) is a critical enzyme cofactor within the glycolytic metabolism network that is fundamentally required to sustain the bioenergetic and anabolic needs of all cells. When deficiencies arise, an adaptive up-regulation in thiamine transporter expression has been described that attempts to restore thiamine homeostasis. However, thiamine deficiencies during chronic alcohol consumption are associated with a down- regulation of thiamine transporters. This antagonism between alcohol and thiamine availability on gene regulation of thiamine transporters is not clearly understood because there is a lack of fundamental knowledge on how thiamine transporters are adaptively regulated. Hence, this application endeavors to understand the cis- and trans-regulatory elements that are responsible for mediating an adaptive up-regulation during thiamine deficiency. Until this mechanistic insight into adaptive regulation is known, understanding how alcohol attenuates the gene expression of thiamine transporters during associated thiamine deficiency will not be realized. The overall objective we have for this application is to determine the transcriptional pathways involved in the adaptive regulation of thiamine transporters during thiamine deficiency. It is our central hypothesis that hypoxia inducible factor-1 (HIF-1 is a centrl transcription factor modulating thiamine availability by trans- activating expression of the thiamine transporter SLC19A3. This hypothesis has been formulated on the basis of preliminary data produced in the applicants' laboratory. The rationale for the proposed research is that once the transcriptional pathways for adaptive thiamine transporter expression are known, new insights and approaches into the underlying effects of alcohol consumption on thiamine transport capacity can be achieved. Guided by our strong preliminary data, this hypothesis will be tested by pursuing two specific aims: 1) Establishing the connection between thiamine deficiency and pseudo-hypoxia on adaptive thiamine transport expression. It is our contention that the metabolic consequences of thiamine deficiency can lead to an accumulation of pyruvate which in turn activates HIF-1 mediated gene regulation. Thus we will use a combination of metabolic profiling and assessment of HIF-1 target gene expression and in particular SLC19A3 during thiamine deficiency. We will also determine if the consequences of alcohol metabolism attenuates the level of pyruvate to counteract this adaptive regulation. 2) Determining HIF-1 mediated trans- activation of SLC19A3 gene expression. Our working hypothesis is that adaptive up-regulation of the thiamine transporter SLC19A3 is conferred through hypoxia response elements in the proximal promoter region. Using a combination of promoter-luciferase assays and ChIP we will establish HIF-1 as an essential trans-activator for SLC19A3 expression. Overall, the proposed research is significant because it is expected to lead to a mechanistic understanding of thiamine transporter regulation within thiamine deficiency related disorders.

描述（由申请人提供）：维生素 B1（硫胺素）是糖酵解代谢网络中的关键酶辅因子，是维持所有细胞的生物能和合成代谢需求所必需的。当出现缺陷时，硫胺素转运蛋白表达的适应性上调已被描述，试图恢复硫胺素稳态。然而，长期饮酒期间硫胺素缺乏与硫胺素转运蛋白的下调有关。酒精和硫胺素可用性之间对硫胺素转运蛋白基因调控的这种拮抗作用尚不清楚，因为缺乏关于硫胺素转运蛋白如何适应性调节的基础知识。因此，本申请致力于了解在硫胺素缺乏期间负责介导适应性上调的顺式和反式调节元件。在了解这种对适应性调节的机制之前，我们无法了解酒精如何在硫胺素缺乏症期间减弱硫胺素转运蛋白的基因表达。我们对此应用程序的总体目标是确定 硫胺素缺乏期间参与硫胺素转运蛋白适应性调节的转录途径。我们的中心假设是缺氧诱导因子-1（HIF-1）是一种中心转录因子，通过反式激活硫胺素转运蛋白SLC19A3的表达来调节硫胺素的可用性。该假设是根据申请人的初步数据制定的。实验室提出的研究的基本原理是，一旦了解了适应性硫胺素转运蛋白表达的转录途径，就可以获得关于饮酒对硫胺素转运能力的潜在影响的新见解和方法。根据我们强有力的初步数据，该假设将通过追求两个具体目标来检验：1）建立硫胺素缺乏和假性缺氧之间对适应性硫胺素转运表达的联系。我们认为，硫胺素缺乏的代谢后果可能导致丙酮酸积累，进而激活 HIF-1 介导的基因调控。因此，我们将结合代谢分析和 HIF-1 靶基因表达评估，特别是硫胺素缺乏期间的 SLC19A3。我们还将确定酒精代谢的后果是否会降低丙酮酸水平以抵消这种适应性调节。 2)确定HIF-1介导的SLC19A3基因表达的反式激活。我们的工作假设是，硫胺素转运蛋白 SLC19A3 的适应性上调是通过近端启动子区域的缺氧反应元件实现的。通过结合启动子荧光素酶检测和 ChIP，我们将确定 HIF-1 作为 SLC19A3 表达的重要反式激活因子。总体而言，拟议的研究意义重大，因为它有望导致对硫胺素缺乏相关疾病中硫胺素转运蛋白调节的机制理解。