Metabolic control of DNA repair in pulmonary fibrosis

肺纤维化中 DNA 修复的代谢控制

基本信息

批准号：
9405624
负责人：
Ross S Summer
金额：
$ 39.29万
依托单位：
THOMAS JEFFERSON UNIVERSITY
依托单位国家：
美国
项目类别：
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/9405624
关键词：
5&apos -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 Exposure to 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

项目摘要

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：高龄是发生肺纤维化的重要危险因素，但潜在的肺纤维化导致这种关联的机制尚不清楚。在这个应用程序中，我们描述了一个基本的衰老通过损害代谢反应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，我们发现博来霉素激活了代谢程序肺泡上皮 II 型细胞 (AEC2) 迅速减少细胞质中乙酰辅酶 A 的利用，同时将乙酰辅酶A生产机制转移到细胞核以增强核心组蛋白乙酰化并增强 DNA 修复。我们发现这些代谢变化的核心是激活 AMPK，对于减少乙酰辅酶 A 的细胞质利用和动员乙酰辅酶 A 至关重要向细胞核产生 ATP-柠檬酸裂解酶 (ACL)。重要的是，我们证明了这种自适应相互作用在老年小鼠的肺部，细胞质和细胞核之间的相互作用受到损害，这在很大程度上是由于 AMPK 的减少活动。此外，我们证明通过增强 AMPK 激活或增加代谢的可用性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年老小鼠未受伤的全肺组织和暴露于博来霉素的培养 AEC 中。综合起来，这些发现使我们提出以下中心假设：我们假设与年龄相关的减少 AMPK 激活有助于增强肺部对博莱霉素的敏感性，该策略旨在恢复 AMPK 激活或增强细胞核内代谢中间体的可用性增强核心组蛋白乙酰化，增加 DNA 修复并减弱肺部纤维化反应。测试针对这些假设，我们提出以下建议：在具体目标 1 中，我们将确定 AMPK 的重要性激活调节细胞代谢和控制核心组蛋白乙酰化/DNA 修复肺泡上皮，我们将确定激活该途径是否会减少肺部纤维化反应年轻和年老的老鼠；在具体目标 2 中，我们将确定 ACL 动员到细胞核的关键作用在博莱霉素进行核心组蛋白乙酰化和 DNA 修复后，我们将确定 ATP-柠檬酸裂合酶是否与年龄匹配的对照组相比，IPF 肺组织中的 IPF 水平降低；最后，在具体目标 3 中，我们将通过确定是否提供不同的 AMPK 活性来建立绕过 AMPK 活性缺陷的治疗效用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和年老小鼠的肺部。总之，该提案将建立老龄化机制增加博来霉素损伤后对肺纤维化的易感性。此外，我们预计这些发现研究将为未来的研究奠定基础，测试新的药理学方法是否有效靶向本申请中详述的代谢途径可以减轻纤维化的发作和/或严重程度肺和其他肺外组织的反应。