Mechanisms of Hemoglobin Adaptation to Hypoxia in High-altitude Rodents

高海拔啮齿动物血红蛋白适应缺氧的机制

• 批准号: 7690723
• 负责人: Jay Storz
• 金额: $ 26.34万
• 依托单位: UNIVERSITY OF NEBRASKA LINCOLN
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-22 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7690723
• 关键词: Adopted; Adult; Aerobic; Affect; Affinity; Alleles; Altitude; American; Amino Acids; Animals; Binding; Binding Sites; Biochemical; Biochemistry; Biological Assay; Blood; Blood Substitutes; Bohr effect; California; Cell Respiration; Cells; Characteristics; Chloride Ion; Chronic; Complex; Computer Analysis; Computer Simulation; DNA Sequence; Deer Mouse; Disease Management; Embryo; Environment; Equilibrium; Erythrocytes; Exhibits; Genes; Genetic; Genetic Polymorphism; Genotype; Globin; Goals; Hemeproteins; Hemoglobin; Human; Hypoxia; In Vitro; Individual; Interdisciplinary Study; Ligand Binding; Ligands; Mammals; Measurement; Measures; Messenger RNA; Metabolism; Minor; Modeling; Modification; Molecular; Molecular Analysis; Molecular Evolution; Mus; Mutation; Natural Selections; Nevada; Nitric Oxide; North America; Nucleotides; Oxygen; Pattern; Peromyscus; Pharmaceutical Preparations; Phosphoric Acid Esters; Physiological Adaptation; Population; Population Genetics; Process; Property; Protein Biochemistry; Protein Isoforms; Proteins; Protons; Reactive Oxygen Species; Relative (related person); Research; Research Project Grants; Rodent; Role; Sampling; Sea; Stress; Structure; Surveys; System; Temperature; Testing; Therapeutic; Tissues; Transcript; Transcriptional Regulation; Variant; base; candidate identification; design; diphosphoglycerate; duplicate genes; experimental analysis; gene therapy; genetic analysis; human disease; insight; molecular site; novel; oxygen transport; protein structure function; public health relevance; research study; stoichiometry; structural biology; theories; tool

DESCRIPTION (provided by applicant): The purpose of the proposed research project is to elucidate the molecular basis of physiological adaptation to high-altitude hypoxia, a condition resulting from a reduced supply of oxygen to the cells of respiring tissues. Specifically, the proposed research will involve a structural and functional analysis of hemoglobin variation that is associated with adaptive variation in the blood biochemistry and aerobic metabolism of high-altitude deer mice (Peromyscus maniculatus). Insights into the molecular mechanisms that allow high-altitude animals to survive and function under conditions of chronic hypoxia can aid our understanding and management of disease processes in humans that compromise the oxygen transport system. By identifying the molecular underpinnings of hypoxia tolerance, it may be possible to replicate the mechanism with novel drug-based therapy, gene therapy, and hemoglobin-based blood substitutes. This highly interdisciplinary study will integrate the tools and theory of molecular population genetics, molecular evolution, structural biology, and protein biochemistry. The specific aims of this research project are (1) To identify the specific amino acid mutations that are responsible for hemoglobin adaptation to hypoxia; (2) To assess whether modifications of hemoglobin structure are also associated with regulatory adjustments in the composition stoichiometry of different hemoglobin isoforms in circulating red blood cells; and (3) To assess the functional consequences of the observed structural and regulatory changes. After first conducting a population-level survey of DNA sequence variation to identify naturally occurring mutations in the globin genes of high-altitude deer mice, this study will involve a population-genetic analysis to infer which of the observed amino-acid changes may be attributable to positive Darwinian selection, an analysis of regulatory variation at the mRNA and protein levels, an 'in silico' computational analysis to predict effects on hemoglobin-oxygen affinity, and an 'in vitro' experimental analysis to assess how the identified structural and regulatory changes influence intrinsic oxygen affinity, as well as sensitivities to temperature, protons (Bohr effect), allosteric effectors, and metabolism of reactive oxygen species and nitric oxide. By identifying mechanisms of hemoglobin adaptation that have evolved in natural populations of high-altitude rodents, the proposed research project should provide novel insights into the molecular basis of hypoxia tolerance. PUBLIC HEALTH RELEVANCE: The goal of the proposed research project is to identify the specific changes in hemoglobin function that have evolved in mice that are native to high-altitude environments. By identifying the specific molecular mechanisms that have enabled high-altitude animals to survive and function under low oxygen conditions, it may be possible to replicate the mechanism in therapeutic treatments of human diseases that compromise the oxygen transport system.

描述（由申请人提供）：拟议研究项目的目的是阐明对高海拔缺氧的生理适应的分子基础，高海拔缺氧是呼吸组织细胞供氧减少引起的一种状况。具体而言，拟议的研究将涉及血红蛋白变异的结构和功能分析，该血红蛋白变异与高海拔鹿鼠（Peromyscus maniculatus）血液生化和有氧代谢的适应性变异相关。深入了解高海拔动物在慢性缺氧条件下生存和发挥功能的分子机制，可以帮助我们理解和管理人类损害氧转运系统的疾病过程。通过确定缺氧耐受的分子基础，有可能用新的基于药物的治疗、基因治疗和基于血红蛋白的血液替代品来复制该机制。这项高度跨学科的研究将整合分子群体遗传学，分子进化，结构生物学和蛋白质生物化学的工具和理论。本研究项目的具体目的是：（1）确定负责血红蛋白适应缺氧的特定氨基酸突变;（2）评估血红蛋白结构的改变是否也与循环红细胞中不同血红蛋白异构体组成化学计量的调节有关;及（3）评估所观察到的结构和调节变化的功能后果。首先进行群体水平的DNA序列变异调查，以确定高海拔鹿鼠珠蛋白基因中自然发生的突变，然后进行群体遗传分析，以推断观察到的氨基酸变化中哪些可能归因于积极的达尔文选择，在mRNA和蛋白质水平上分析调节变异，“计算机模拟”计算分析，以预测对血红蛋白-氧亲和力的影响，以及"体外“实验分析，以评估所识别的结构和调节变化如何影响固有氧亲和力，以及对温度、质子（玻尔效应），变构效应，以及活性氧和一氧化氮的代谢。通过识别在高海拔啮齿动物的自然种群中进化的血红蛋白适应机制，拟议的研究项目应该为缺氧耐受性的分子基础提供新的见解。公共卫生相关性：拟议研究项目的目标是确定在高海拔环境中土生土长的小鼠中进化的血红蛋白功能的具体变化。通过确定使高海拔动物能够在低氧条件下生存和发挥功能的特定分子机制，有可能在损害氧气运输系统的人类疾病的治疗中复制该机制。