Developmental Pharmacology of Mitochondrial and Cytosolic GSTZ1

线粒体和胞质 GSTZ1 的发育药理学

• 批准号: 9176607
• 负责人: Margaret Olive James
• 金额: $ 34.01万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9176607
• 关键词: 21 year old; Adolescent; Adult; Adverse drug effect; Adverse effects; Affect; Age; Animals; Anions; Binding Sites; Brain; Bromides; Catabolism; Cells; Child; Chloride Ion; Chlorides; Chronic; Clinical; Clinical Trials; Cytosol; Development; Dichloroacetate; Dichloroacetic Acid; Disease; Dose; Drug Kinetics; Energy Metabolism; Environmental Exposure; Enzymes; Exhibits; Extrahepatic; Frequencies; Genetic; Glutathione; Glutathione S-Transferase; Goals; Growth; Haplotypes; Heart; Hepatic; Human; Individual; Infant; Intestines; Investigational Drugs; Iodides; Isomerase; Kidney; Lactic Acidosis; Life; Link; Liver; Longevity; Metabolic; Metabolic Biotransformation; Metabolism; MicroRNAs; Mitochondria; Mitochondrial Matrix; Mitochondrial Proteins; Modeling; Nature; Oxidative Phosphorylation; PDH kinase; Pathway interactions; Pattern; Peripheral Nervous System Diseases; Pharmaceutical Preparations; Pharmacodynamics; Pharmacology; Physiological; Play; Property; Proteins; Rattus; Recombinants; Research; Role; Salts; Sampling; Site; Solid Neoplasm; System; Therapeutic; Therapeutic Uses; Thinking; Tissues; Transferase; Tyrosine; Variant; adduct; age difference; age related; aged; base; dechlorination; dehalogenation; genetic makeup; glyoxylate; individual patient; individualized medicine; inhibitor/antagonist; juvenile animal; knock-down; mRNA Expression; maleylacetone; pulmonary arterial hypertension; response

Project Summary. The broad, long-term objectives of this research are to understand the properties of glutathione transferase Z1 (GSTZ1) and its role in the elimination of the investigational drug dichloroacetic acid (DCA) across the human lifespan. This is important because while DCA, an inhibitor of mitochondrial pyruvate dehydrogenase kinase, has therapeutic benefits as a metabolic regulator in treating lactic acidosis, certain solid tumors and pulmonary arterial hypertension, it exhibits marked age- and genetics- related individual variability in pharmacokinetics that are linked to DCA's side effects. The first step in DCA metabolism is dechlorination to glyoxylate, catalyzed by GSTZ1. Also known as maleylacetoacetate isomerase, GSTZ1 plays an important physiological role in isomerizing endogenous reactive metabolites of the tyrosine catabolism pathway, maleylacetoacetate and maleylacetone. GSTZ1 is expressed chiefly in the liver, but also in kidney, intestine, brain and heart. It is the only enzyme known to catalyze the dehalogenation of DCA to its primary metabolite, glyoxylate. Although it is well recognized that DCA inhibits its own metabolism as well as that of its endogenous substrates, through inactivation of GSTZ1, the reasons for the marked individual variability in pharmacokinetics of DCA after repeated doses are only partially understood. Most adults clear repeated doses of DCA more slowly than children, and clearance is GSTZ1 haplotype dependent in children and adults. There is preliminary evidence that extrahepatic sites of DCA metabolism become of greater importance relative to liver following DCA treatment, and that this is age-dependent. Finally, chloride (Cl-) concentration affects the rate of inactivation of GSTZ1 by DCA in a haplotype-dependent manner; the much lower [Cl-] in mitochondria compared with cytosol is thought to be a factor in the more rapid inactivation of the mitochondrial matrix enzyme, and could be a factor in the observed age-dependent differences, as intracellular [Cl-] varies with age. The mechanism of how Cl- protects GSTZ1 from DCA-dependent inactivation is not known. This application seeks to examine reasons for age- and genetics- related changes in expression and activity of GSTZ1 in people. Three specific aims are proposed. The first specific aim will study the role of microRNA (miR) in regulating the documented age-related changes in hepatic GSTZ1 expression. This aim will use banked human liver of different aged donors to identify miRs, and cell-based systems to verify involvement. The second specific aim will investigate the mechanism of protection of GSTZ1 from inactivation by DCA in the presence of Cl- and certain other anions, and the influence of haplotype. Expressed recombinant GSTZ1A and 1B will be crystallized and the binding sites of DCA and anions studied. The third specific aim will use juvenile and adult rats as models of children and adults to examine the roles of extrahepatic tissues relative to liver in the expression and activity of GSTZ1 following multiple DCA doses, to mimic the clinical use.

项目摘要。 这项研究的广泛、长期目标是了解谷胱甘肽转移酶 Z1 的特性 (GSTZ1) 及其在人体消除研究药物二氯乙酸 (DCA) 中的作用 寿命。这很重要，因为虽然 DCA 是线粒体丙酮酸脱氢酶激酶的抑制剂， 作为代谢调节剂，在治疗乳酸性酸中毒、某些实体瘤和肺肿瘤方面具有治疗作用 动脉高血压，其药代动力学表现出明显的年龄和遗传相关的个体差异 与 DCA 的副作用有关。 DCA代谢的第一步是脱氯为乙醛酸， 由 GSTZ1 催化。 GSTZ1 也称为马来酰乙酰乙酸异构酶，在生理学中发挥着重要作用。 在酪氨酸分解代谢途径的内源性反应性代谢物马来酰乙酰乙酸异构化中的作用 和马来酰丙酮。 GSTZ1主要在肝脏中表达，但也在肾、肠、脑和心脏中表达。这是 已知唯一能催化 DCA 脱卤为其主要代谢物乙醛酸的酶。虽然 众所周知，DCA 通过以下方式抑制自身代谢及其内源性底物的代谢： GSTZ1失活，DCA药代动力学显着个体差异的原因 对重复剂量的了解仅是部分的。大多数成年人清除重复剂量的 DCA 的速度比 儿童，清除率在儿童和成人中依赖于 GSTZ1 单倍型。有初步证据 DCA 后 DCA 代谢的肝外位点相对于肝脏变得更加重要 治疗，并且这与年龄有关。最后，氯化物 (Cl-) 浓度影响灭活速率 DCA 以单倍型依赖性方式检测 GSTZ1；与细胞质相比，线粒体中的 [Cl-] 低得多 被认为是线粒体基质酶更快失活的一个因素，并且可能是 观察到的年龄依赖性差异的因素，因为细胞内 [Cl-] 随年龄而变化。其机理如何 Cl- 保护 GSTZ1 免受 DCA 依赖性失活尚不清楚。 本申请旨在研究与年龄和遗传相关的表达和活性变化的原因。 人体内的 GSTZ1。提出了三个具体目标。第一个具体目标是研究 microRNA 的作用 (miR) 调节已记录的肝脏 GSTZ1 表达的年龄相关变化。这个目标将使用 储存不同年龄捐赠者的人类肝脏来识别 miR，并使用基于细胞的系统来验证参与情况。 第二个具体目标是研究 DCA 保护 GSTZ1 免于失活的机制。 Cl- 和某些其他阴离子的存在以及单倍型的影响。表达重组 GSTZ1A 和 1B 将被结晶并研究 DCA 和阴离子的结合位点。第三个具体目标将利用青少年 和成年大鼠作为儿童和成人模型，以检查肝外组织相对于肝脏的作用 多次 DCA 剂量后 GSTZ1 的表达和活性，以模拟临床使用。