Mechanistic Studies and Translational Applications of Stress Signaling in Anemia

贫血中应激信号传导的机制研究和转化应用

• 批准号: 9177621
• 负责人: Joseph Anthony Garcia
• 金额: $ 40.48万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9177621
• 关键词: Ablation; Acetate-CoA Ligase; Acetates; Acetyl Coenzyme A; Acetylation; Acetylesterase; Acetyltransferase; Acute; Adult; Affect; Anemia; Animals; Appearance; Biochemical; Biological; Blood Transfusion; Bolus Infusion; Cell Culture Techniques; Cell Nucleus; Cells; Chronic; Clustered Regularly Interspaced Short Palindromic Repeats; Complex; Cytosol; Data; Deacetylation; Development; Disease; Enzymes; Epithelial Cells; Erythrocytes; Erythropoiesis; Erythropoietin; Flare; Fostering; Gene Targeting; Genes; Goals; Growth; Health Care Costs; Hemolytic Anemia; Hepatocyte; Hormones; Hypertension; Hypoxia; Injection of therapeutic agent; Intestines; Iron; Iron deficiency anemia; Kidney; Knockout Mice; Knowledge; Link; Liver; Lysine; Malignant Neoplasms; Mammalian Cell; Mammals; Mediating; Medical; Minor; Modeling; Modification; Molecular; Morbidity - disease rate; Mouse Strains; Mus; Mutant Strains Mice; Mutation; Nuclear; Nuclear Export; Nuclear Localization Signal; Nuclear Translocation; Oxidative Stress; Pathway interactions; Patients; Physiological; Physiological Processes; Process; Production; Recombinant Erythropoietin; Renal Interstitial Cell; Reporting; Role; Signal Transduction; Stress; Testing; Therapeutic Intervention; Thrombosis; Tissues; Venous; absorption; antioxidant enzyme; bHLH-PAS factor HLF; base; biological adaptation to stress; congenic; cost; hypoxia inducible factor 1; innovation; insight; iron supplement; loss of function; loss of function mutation; member; mortality; mutant; novel; null mutation; response; transcription factor; treatment strategy; uptake

ABSTRACT Anemia is a common medical condition with significant morbidity and mortality, especially if present with other diseases. The development of recombinant Erythropoietin (Epo), a pro-erythrocyte hormone produced in adult kidney and liver during anemia, revolutionized anemia treatment. Unfortunately, non- physiological bolus Epo also promotes thrombosis, hypertension, and cancer growth. Furthermore, many anemia patients are iron deficient and require parenteral or intra-venous iron supplements, which are poorly tolerated. Endogenous Epo production and iron uptake are tightly controlled by the stress- responsive transcription factor Hypoxia Inducible Factor 2 (HIF-2). During hypoxia, HIF-2 undergoes cyclical acetylation/deacetylation modifications, which augment HIF-2 signaling. HIF-2 acetylation is rate-limiting and conferred selectively by the acetyltransferase Cbp. Acetylation of HIF-2 by Cbp is regulated by a specific acetyl CoA generator, acetate-dependent acetyl CoA synthetase 2 (Acss2), which normally is present in the cytosol. Acetate, whether generated endogenously in anemic mice or provided exogenously as a therapeutic intervention, functions as a biochemical flare to activate Cbp- mediated HIF-2 acetylation and is accompanied by the de novo appearance of nuclear Acss2. We hypothesize that acetate induces translocation of Acss2 from the cytosol to the nucleus, where it generates a specific acetyl CoA pool used by Cbp to acetylate HIF-2 and augment HIF-2 signaling. The goal of this proposal is to elucidate the mechanism and biological role for Acss2 in mammals. We will do so with three aims employing integrative molecular, cellular, and animal studies. First, we will identify the molecular basis for Acss2 nuclear localization using molecular and biochemical assessments in cell culture models. Second, we will assess how restricting Acss2 to the cytosol or changing the genetic background of an Acss2 null mutation through CRISPR-modified targeting or congenic breedings in mice, respectively, affects the erythropoietic response to anemia. Third, we will determine what effect cell-specific ablation of Acss2 has on molecular and physiological responses to acute anemia and iron uptake in mice. Deciphering how the acetate/Acss2 switch regulates HIF-2 signaling will provide key insights into a novel signal transduction mechanism. Defining its role in the mammalian response to anemia will foster innovative and economical treatment strategies for anemic patients, which may significantly reduce costs associated with current approaches.

摘要 贫血是一种常见的医学疾病，具有显著的发病率和死亡率，特别是如果存在 与其他疾病。促红细胞生成素的研究进展 在成人贫血时肾脏和肝脏中产生，彻底改变了贫血治疗。不幸的是，非- 生理性大剂量Epo还促进血栓形成、高血压和癌症生长。此外，委员会认为， 许多贫血患者缺铁，需要胃肠外或静脉内铁补充剂， 耐受性差。内源性Epo的产生和铁的吸收受到应激的严格控制- 缺氧诱导因子2（HIF-2）。缺氧时，HIF-2 环状乙酰化/脱乙酰化修饰，其增强HIF-2信号传导。HIF-2乙酰化是 限速和赋予选择性的乙酰转移酶Cbp。Cbp对HIF-2的乙酰化作用 由特定的乙酰辅酶A生成器，乙酸依赖性乙酰辅酶A合成酶2（Acss 2）， 其通常存在于胞质溶胶中。醋酸盐，无论是贫血小鼠内源性产生，还是 作为治疗性干预外源性提供，作为生物化学耀斑激活Cbp， 介导的HIF-2乙酰化，并伴随着从头出现的核Acss 2。 我们假设醋酸盐诱导Acss 2从胞质转移到细胞核， 产生特异性的乙酰辅酶A库，Cbp使用它来乙酰化HIF-2并增强HIF-2信号传导。的 本研究的目的是阐明Acss 2在哺乳动物中的作用机制和生物学作用。我们将 这样做有三个目的，采用综合分子，细胞和动物研究。一是 使用分子和生物化学方法鉴定Acss 2核定位的分子基础 在细胞培养模型中进行评估。其次，我们将评估如何限制Acss 2的细胞质或 通过CRISPR修饰的靶向改变Acss 2无效突变的遗传背景，或 在小鼠中的同源breasthole分别影响对贫血的红细胞生成反应。三是 确定Acss 2的细胞特异性消融对以下分子和生理反应的影响： 急性贫血和小鼠铁摄取。破解醋酸盐/Acss 2开关如何调节HIF-2 信号转导将提供一个新的信号转导机制的关键见解。确定其在 哺乳动物对贫血的反应将促进贫血的创新和经济的治疗策略 患者，这可能会大大降低与当前方法相关的成本。