Developmental Pharmacology of cytosolic and mitochondrial GSTZ1-1/MAAI

细胞质和线粒体 GSTZ1-1/MAAI 的发育药理学

基本信息

批准号：
8531995
负责人：
Margaret Olive James
金额：
$ 31.3万
依托单位：
UNIVERSITY OF FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-01 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8531995
关键词：
Acids Adult Adverse effects Affect Age Anions Antineoplastic Agents Catabolism Child Chloride Ion Chlorides Chronic Clinical Cytosol Decarboxylation Development Dichloroacetate Dichloroacetic Acid Disease Dose Drug Kinetics Environmental Exposure Enzymes Exhibits Exposure to Genetic Genotype Glutathione S-Transferase Glyoxylates Goals Half-Life Haplotypes Hepatic Hepatocyte Heterozygote Hour Human In Vitro Individual Lactic Acidosis Link Liver Liver Mitochondria Location Longevity Maleylacetoacetate isomerase Measurement Measures Mediating Metabolic Metabolic Biotransformation Metabolism Mitochondria Mitochondrial Matrix Mutation Nature Oxidoreductase PDH kinase Peripheral Nervous System Diseases Persons Pharmaceutical Preparations Pharmacodynamics Pharmacology Phosphotransferases Physiological Play Process Property Proteins Rattus Recombinants Relative (related person)Reporting Research Role Site Solid Neoplasm Therapeutic Therapeutic Effect Therapeutic Uses Time Toxic effect Translating Tyrosine Tyrosine Metabolism Pathway Variant Work adduct age related dechlorination dehalogenation drinking water environmental chemical enzyme activity fumarylacetone glyoxylate in vivo maleylacetone protein expression pulmonary arterial hypertension response therapeutic target

项目摘要

DESCRIPTION (provided by applicant): The broad, long-term objectives of this research are to understand the properties of glutathione transferase Z1- 1 (GSTZ1-1) and its role in the elimination of haloacetic acids, particularly dichloroacetic acid (DCA) across the human lifespan. This is important because while DCA has therapeutic benefits in treating certain solid tumors, lactic acidosis and pulmonary arterial hypertension, it exhibits marked individual variability in pharmacokinetics, and can cause side effects at high doses, particularly in adults. The first step in DCA metabolism is dechlorination to glyoxylate, catalyzed by GSTZ1-1. Also known as maleylacetoacetate isomerase, and playing an important role in catabolism of tyrosine, GSTZ1-1 is expressed mainly in the liver and is the only enzyme known to catalyze the dehalogenation of haloacetic acids, including DCA. Although it is well recognized that DCA inhibits its own metabolism and the metabolism of maleylacetoacetate and its decarboxylation product, maleylacetone, almost certainly because DCA inactivates GSTZ1-1, the reasons for the marked individual variability in pharmacokinetics of DCA after repeated doses are only beginning to be understood. Most adults clear repeated doses of DCA more slowly than most children. Persons with different GSTZ1-1 haplotypes appear to differ in their response to repeated doses of DCA. Recent in vitro work showed that chloride concentration affected the rate of inactivation of GSTZ1-1 by DCA in a haplotype-dependent manner. In addition to its well-known presence in liver cytosol, GSTZ1-1 has recently been found to exist in the mitochondrial matrix. This is the same location as pyruvate dehydrogenase kinase, DCA's pharmacodynamics site of action. Most of the downstream metabolism of the DCA metabolite, glyoxylate, occurs in the mitochondria suggesting the importance of this site in the overall disposition of DCA. This application seeks to examine age-related changes in expression and activity of GSTZ1-1 across the human lifespan and ascertain the properties of the newly-discovered mitochondrial enzyme. Three specific aims are proposed. The first specific aim will investigate age-related changes in hepatic GSTZ1-1 expression and activity in mitochondria and cytosol. The second specific aim will examine the properties of the mitochondrial enzyme, with respect to the relative loss of mitochondrial versus cytosolic GSTZ1-1 following in vivo exposure to DCA, and the ability of the mitochondrial GSTZ1-1/MAAI to convert the physiologically important substrate of GSTZ1-1, maleylacetone, to fumarylacetone. The third specific aim will use in vitro studies to investigate sensitivity of mitochondrial GSTZ1-1 to inactivation by DCA and the role of chloride and haplotype as determinants of the rate and mechanism of inactivation of cytosolic, mitochondrial and expressed GSTZ1-1 by DCA.

描述（由申请人提供）：这项研究的广泛的长期目标是了解谷胱甘肽转移酶Z1- 1（GSTZ1-1）的特性及其在消除卤乙酸中的作用，尤其是二氯乙酸（DCA）跨越二氯乙酸（DCA）人类的寿命。这很重要，因为尽管DCA在治疗某些实体瘤，乳酸性酸中毒和肺动脉高压方面具有治疗益处，但它在药代动力学中表现出明显的个体变异性，并且会在高剂量下引起副作用，尤其是在成年人中。 DCA代谢的第一步是由GSTZ1-1催化的乙二基脱氯。 GSTZ1-1也称为甲基乙酸异构酶，在酪氨酸的分解代谢中起重要作用，主要在肝脏中表达，并且是唯一已知的酶催化包括DCA在内的卤乙酸的去解息。尽管众所周知，DCA抑制了其自身的代谢和甲基乙酸乙酸丙烷酰乙酸的代谢及其脱羧产物Maleyylacetone，几乎可以肯定，因为DCA灭活GSTZ1-1，这是重复剂量DCA的明显个性变异的原因，仅在重复剂量后才开始使用DCA。被理解。大多数成年人比大多数儿童更慢，重复剂量的DCA。具有不同GSTZ1-1单倍型的人似乎对重复剂量DCA的反应有所不同。最近的体外工作表明，氯化物的浓度影响了DCA以单倍型依赖性方式通过DCA对GSTZ1-1的失活率。除了在肝细胞质中著名的存在外，GSTZ1-1最近被发现存在于线粒体基质中。这与丙酮酸脱氢酶激酶（DCA的药效动力学部位）相同。 DCA代谢产物（乙二醇）的大多数下游代谢都发生在线粒体中，这表明该位点在DCA的整体处置中的重要性。该应用程序旨在检查与年龄相关的GSTZ1-1在人类寿命中的表达和活性的变化，并确定新发现的线粒体酶的特性。提出了三个具体目标。第一个具体目的将研究线粒体和细胞质中与年龄相关的肝GSTZ1-1表达和活性的变化。第二个具体目标将在体内暴露于DCA之后的线粒体与胞质GSTZ1-1的相对损失以及线粒体GSTZ1-1/MAAI转换物理学上重要的副底物转换的能力，以检查线粒体酶的特性。 GSTZ1-1，甲基丙酮，促富马酮。第三个具体目的将利用体外研究来研究线粒体GSTZ1-1对DCA失活的敏感性，以及氯化物和单倍型的作用是杀菌率的决定因素和灭活胞质，线粒体和线粒体和DCA表达GSTZ1-1的机制。