Metabolic control of DNA repair in pulmonary fibrosis

肺纤维化中 DNA 修复的代谢控制

• 批准号: 9238175
• 负责人: Ross S Summer
• 金额: $ 40.24万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9238175
• 关键词: 5' -AMP-activated protein kinase; ATP Citrate (pro-S)-Lyase; Acetates; Acetyl Coenzyme A; Age; Age-Months; Aging; Alveolar; Attenuated; Biological; Bleomycin; Bypass; Cell Nucleus; Clinical; Clinical Management; Cytoplasm; DNA Damage; DNA Repair; DNA biosynthesis; Data; Defect; Development; Disease; Elderly; Enzymes; Epithelial; Epithelial Cells; Epithelium; Fibrosis; Fostering; Foundations; Future; Grant; Growth Factor; Histone Acetylation; Histones; Human; Impairment; In Vitro; Injury; Investigation; Lipids; Lung; Mediating; Metabolic; Metabolic Control; Metabolic Pathway; Metabolism; Molecular Genetics; Mus; Mutagens; Pathogenesis; Pathway interactions; Patients; Pharmacology; Phosphorylation; Play; Predisposition; Production; Protein Acetylation; Protein Kinase; Pulmonary Fibrosis; Pyruvate; Radiation; Research; Risk Factors; Role; STK11 gene; Severities; Structure of parenchyma of lung; Techniques; Testing; Therapeutic; Tissues; Type II Epithelial Receptor Cell; age related; alveolar epithelium; cancer cell; genotoxicity; in vivo; indium-bleomycin; loss of function; novel; novel therapeutics; programs; response

ABSTRACT: Advanced age is an important risk factor for developing pulmonary fibrosis but the underlying mechanisms leading to this association are not understood. In this application, we describe a fundamental mechanism by which aging promotes the development of pulmonary fibrosis by impairing metabolic responses in the alveolar epithelium of the lung. In young mice, we show that bleomycin activates a metabolic program in which alveolar epithelial type II cells (AEC2) rapidly reduce utilization of acetyl-CoA in the cytoplasm and simultaneously divert the machinery for acetyl-CoA production to the nucleus in order to enhance core histone acetylation and augment DNA repair. We found that central to these metabolic changes is the activation of AMPK, which is critical for both reducing cytoplasmic utilization of acetyl CoA and mobilizing the acetyl-CoA producing enzyme ATP-citrate lyase (ACL) to the nucleus. Importantly, we show that this adaptive interplay between the cytoplasm and nucleus is impaired in the lungs of older mice due, in large part, to reduced AMPK activity. Further, we demonstrate that by enhancing AMPK activation or increasing the availability of metabolic intermediates we can augment core histone acetylation, increase DNA repair and attenuate fibrotic responses in uninjured whole lung tissues of older mice and in cultured AECs exposed to bleomycin. Taken together, these findings led us to propose the following central hypothesis: We hypothesize that age-related decreases in AMPK activation contribute to the enhanced susceptibility of the lung to bleomycin and that strategies aimed at restoring AMPK activation or enhancing the availability of metabolic intermediates in the nucleus will enhance core histone acetylation, increase DNA repair and attenuate fibrotic responses in the lung. To test these hypotheses we propose the following: In Specific Aim 1, we will establish the importance of AMPK activation in the regulating cellular metabolism and controlling core histone acetylation/DNA repair in the alveolar epithelium and we will determine whether activating this pathway reduces fibrotic responses in lungs of young and old mice; In Specific Aim 2, we will establish the critical role of ACL mobilization to the nucleus after bleomycin for core histone acetylation and DNA repair and we will determine whether ATP-citrate lyase levels are reduced in IPF lung tissue compared to age-matched controls; and lastly, in Specific Aim 3, we will establish the therapeutic utility of bypassing deficient AMPK activity by determining whether supplying different metabolic substrates restores core histone acetylation, augments DNA repair and attenuates fibrotic responses in lungs of young and old mice. In summary, this proposal will establish the mechanisms by which aging enhances susceptibility to lung fibrosis after bleomycin insult. Further, we anticipate that findings from these studies will lay the foundation for future investigations testing whether novel pharmacological approaches targeting metabolic pathways detailed in this application can attenuate the onset and/or severity of fibrotic responses in lung, and in other extrapulmonary tissues.

摘要：高级年龄是发展肺纤维化的重要危险因素 导致这种关联的机制尚不清楚。在此应用程序中，我们描述了一个基本 衰老通过损害代谢反应而促进肺纤维化发展的机制 在肺的肺泡上皮中。在年轻小鼠中，我们表明博来霉素激活了一项代谢程序 哪种肺泡上皮II型细胞（AEC2）迅速降低了细胞质中乙酰辅酶A的利用 同时将乙酰-COA产生的机械转移到核，以增强核心组蛋白 乙酰化和增强DNA修复。我们发现这些代谢变化的核心是激活 AMPK，这对于降低乙酰基COA的细胞质利用和动员乙酰辅酶A至关重要 产生酶ATP-citrate裂解酶（ACL）到核。重要的是，我们表明这种自适应相互作用 细胞质和细胞核之间在大小鼠的肺中受损，这在很大程度上是由于AMPK减少的。 活动。此外，我们证明，通过增强AMPK激活或增加代谢的可用性 中级我们可以增强核心组蛋白乙酰化，增加DNA修复并减弱纤维化反应 在较老小鼠和暴露于博来霉素的培养的AEC中，在未受伤的整个肺组织中。在一起， 这些发现使我们提出了以下中心假设：我们假设与年龄相关的下降是 在AMPK激活中，有助于增强肺对博来霉素的敏感性，并有针对性的策略 恢复AMPK激活或增强核中代谢中间体的可用性将 增强核心组蛋白乙酰化，增加DNA修复并减弱肺中的纤维化反应。测试 这些假设我们提出以下建议：在特定目标1中，我们将确定AMPK的重要性 调节细胞代谢和控制核心组蛋白乙酰化/DNA修复的激活 肺泡上皮，我们将确定激活该途径是否会降低肺部的纤维化反应 老鼠和老鼠；在特定的目标2中，我们将建立ACL动员到原子核的关键作用 博来霉素用于核心组蛋白乙酰化和DNA修复，我们将确定AT​​P-citrate裂解酶是否是否 与年龄匹配的对照相比，IPF肺组织的水平降低；最后，在特定的目标3中，我们将 通过确定是否提供不同 代谢底物恢复核心组蛋白乙酰化，增强DNA修复并减弱纤维化反应 在年轻老鼠的肺中。总而言之，该提议将建立衰老的机制 博来霉素侮辱后增强对肺纤维化的敏感性。此外，我们预计从这些发现 研究将奠定未来研究的基础，以测试新型药理方法是否采用 靶向本应用中详细详细介绍的代谢途径可以减弱纤维化的发作和/或严重程度 肺部和其他肺外组织的反应。