Sirtuins in Lung Aging and Fibrosis

Sirtuins 在肺衰老和纤维化中的作用

• 批准号: 10610127
• 负责人: Victor J. Thannickal
• 金额: --
• 依托单位: SOUTHEAST LOUISIANA VETERANS HEALTH CARE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10610127
• 关键词: Accounting; Affect; Age; Aging; Alveolar Macrophages; Apoptosis; Applications Grants; Award; Binding Proteins; Bioenergetics; Bleomycin; Blood Vessels; CREBBP gene; Cell Aging; Cicatrix; Clinical; Complementary DNA; Constitution; Cyclic AMP-Responsive DNA-Binding Protein; Data; Development; Disease; Down-Regulation; EP300 gene; Epigenetic Process; Event; Fibroblasts; Fibrosis; Gases; Genetic; Heart; Human; Immunohistochemistry; Impairment; Incidence; Kidney; Lead; Liver; Lung; Lung diseases; Mediating; Mitochondria; Modeling; Molecular; Morbidity - disease rate; Mus; Nuclear; Paracrine Communication; Patients; Pharmaceutical Preparations; Pharmacology; Phase; Phenotype; Pirfenidone; Plasmids; Population; Predisposition; Prevalence; Pulmonary Fibrosis; Recovery; Regulation; Resistance; Resolution; Respiratory Failure; Risk Factors; Role; Signal Pathway; Signal Transduction; Sirtuins; Structure of parenchyma of lung; Survival Rate; Testing; Time; Tissues; Transforming Growth Factors; United States; United States Department of Veterans Affairs; aged; body system; burden of illness; clinical efficacy; disabling disease; epigenetic regulation; fibrotic lung; fibrotic lung disease; human subject; idiopathic pulmonary fibrosis; improved; in vivo; injury and repair; insight; lung injury; macrophage; mitochondrial dysfunction; mortality; nintedanib; novel therapeutic intervention; novel therapeutics; older patient; paracrine; patient population; profibrotic cytokine; protective effect; reconstitution; senescence; transcription factor

Human fibrotic disorders affect many organ systems including heart, blood vessels, kidney, liver and lung, accounting for excessive disease burden in the U.S., including among our Veterans Administration (VA) patient population. The most common fibrotic lung disease, idiopathic pulmonary fibrosis (IPF), is characterized by excessive scar tissue formation and irreversible destruction of the lung parenchyma, resulting in gas-exchange abnormalities and ultimately respiratory failure. Aging is strongest risk factor for IPF; however, the cellular/molecular mechanisms that account for the age-associated predilection to fibrotic disease are only beginning to be explored. Improved understanding of the role of aging in this disease will aid in the development of novel therapies with greater clinical efficacy. In support of this VA Merit Award renewal application, we have made several recent contributions to our understanding of aging mechanisms in lung injury and repair mechanisms. Human subjects with IPF express low levels of the mitochondrial sirtuin, SIRT3, in myofibroblastic foci and in ex-vivo fibroblasts isolated from IPF lungs. This down-regulation of SIRT3 is replicated in an aging model of non-resolving fibrosis in mice; while fibrosis in young mice largely resolves over 2-4 months post-bleomycin, aged mice manifest persistent fibrosis. Our data indicate that this capacity for fibrosis resolution in young mice is associated with recovery of SIRT3 levels in the late reparative phase of lung injury, while this is absent in aged mice. However, re-constitution of SIRT3 (via lung-targeted non-viral cDNA plasmid delivery) restores the capacity for fibrosis resolution in aged mice. This protective effect is associated with in-vivo activation of FoxO3a, evidenced by higher levels of nuclear FoxO3a. Both cellular senescence and the pro-fibrotic cytokine, transforming growth factor-β1 (TGF- β1) induce a down-regulation of SIRT3 and FoxO3a, events that lead to mitochondrial dysfunction, senescence and apoptosis resistance of lung fibroblasts. Our studies also support the possibility that modulation of SIRT3 in alveolar macrophages regulates fibroblast activation of FoxO3a by a paracrine mechanism. Additionally, the histone acetyltransferases, p300 and cyclic AMP-response element binding protein (CREB)-binding protein (CBP), are implicated in the epigenetic down-regulation of SIRT3 by TGF-β1 and cellular senescence. Impaired activation of the SIRT3-FoxO3a signaling axis promotes a senescent and apoptosis-resistant fibroblast phenotype, which drives persistent/non-resolving fibrosis. The central hypothesis to be tested in this grant proposal is that persistent/non-resolving fibrosis associated with aging is mediated by impaired activation of Foxo3a in fibroblasts, either by SIRT3 deficiency in fibroblasts themselves or by macrophage-derived paracrine mechanisms, contributes to mitochondrial dysfunction, senescence and apoptosis resistance of lung fibroblasts. Our specific aims are to: (1) elucidate p300/CBP-dependent epigenetic regulation of SIRT3 in lung fibroblasts and alveolar macrophages that mediate pro-resolution phenotypes; (2) investigate the role of the SIRT3-FoxO3a signaling axis in restoring mitochondrial bioenergetics and apoptosis susceptibility to senescent/fibrotic lung fibroblasts; and (3) determine whether reconstitution of SIRT3 by genetic/pharmacologic approaches promotes fibrosis resolution in aged mice via the activation of FoxO3a in lung fibroblasts. The completion of the Aims in this proposal will: (a) uncover epigenetic mechanisms that control SIRT3 expression with cellular senescence/aging; (b) provide mechanistic insights into the role of SIRT3-FoxO3a signaling in the regulation of mitochondrial bioenergetics and cellular plasticity/fate; and (c) elucidate macrophage-fibroblast crosstalk and SIRT3 regulation of pro-resolving macrophages; and (d) provide proof-of-concept that activation of the SIRT3-FoxO3a signaling pathway promotes fibrosis resolution, leading to new therapeutic approaches for progressive lung diseases.

人类纤维化疾病影响许多器官系统，包括心脏、血管、肾脏、肝脏和肺， 解释了美国过度的疾病负担，包括我们的退伍军人管理局 (VA) 患者 人口。最常见的纤维化肺病是特发性肺纤维化（IPF），其特征是 过度的疤痕组织形成和肺实质不可逆的破坏，导致气体交换 异常并最终导致呼吸衰竭。衰老是 IPF 的最强危险因素；然而， 解释与年龄相关的纤维化疾病倾向的细胞/分子机制仅是 开始被探索。更好地了解衰老在这种疾病中的作用将有助于 开发具有更大临床疗效的新疗法。 为了支持 VA 优异奖续签申请，我们最近为我们的项目做出了几项贡献 了解肺损伤的衰老机制和修复机制。患有 IPF Express 的人类受试者 在肌成纤维细胞病灶和从 IPF 中分离的离体成纤维细胞中，线粒体 Sirtuin、SIRT3 水平较低 肺。 SIRT3 的这种下调在小鼠非消退性纤维化衰老模型中得到了复制。尽管 年轻小鼠的纤维化在博来霉素后 2-4 个月内基本得到缓解，老年小鼠则表现出持续性纤维化。 我们的数据表明，年轻小鼠的纤维化消退能力与 SIRT3 的恢复相关 肺损伤后期修复阶段的水平，而老年小鼠则不存在这种情况。然而，重构 SIRT3（通过肺部靶向非病毒 cDNA 质粒递送）恢复老年人纤维化消退的能力 老鼠。这种保护作用与 FoxO3a 的体内激活有关，较高水平的 FoxO3a 证明了这一点 核 FoxO3a。细胞衰老和促纤维化细胞因子转化生长因子-β1 (TGF- β1) 诱导 SIRT3 和 FoxO3a 下调，导致线粒体功能障碍， 肺成纤维细胞的衰老和凋亡抵抗。我们的研究也支持这样的可能性： 肺泡巨噬细胞中 SIRT3 的调节通过旁分泌调节 FoxO3a 的成纤维细胞激活 机制。此外，组蛋白乙酰转移酶、p300 和环 AMP 反应元件结合 蛋白 (CREB) 结合蛋白 (CBP)，参与 TGF-β1 对 SIRT3 的表观遗传下调 和细胞衰老。 SIRT3-FoxO3a 信号轴的激活受损会促进衰老和 抗凋亡成纤维细胞表型，导致持续性/非消退性纤维化。 本拨款提案要测试的中心假设是持续性/非解决性纤维化 与衰老相关的衰老过程是由成纤维细胞中 Foxo3a 激活受损介导的，或者是由于 SIRT3 缺陷所致 成纤维细胞本身或通过巨噬细胞衍生的旁分泌机制，有助于线粒体 肺成纤维细胞功能障碍、衰老和凋亡抵抗。 我们的具体目标是：(1) 阐明肺中 SIRT3 的 p300/CBP 依赖性表观遗传调控 介导促解析表型的成纤维细胞和肺泡巨噬细胞； (2) 探究角色的作用 SIRT3-FoxO3a 信号轴在恢复线粒体生物能和细胞凋亡易感性中的作用 衰老/纤维化的肺成纤维细胞； (3) 确定 SIRT3 是否通过以下方式重建： 遗传/药理学方法通过激活 FoxO3a 促进老年小鼠纤维化消退 肺成纤维细胞。完成本提案中的目标将：(a) 揭示表观遗传机制， 控制 SIRT3 表达与细胞衰老； (b) 提供对作用的机制性见解 SIRT3-FoxO3a 信号传导在线粒体生物能量和细胞可塑性/命运调节中的作用；和（三） 阐明巨噬细胞-成纤维细胞串扰和 SIRT3 对促解析巨噬细胞的调节； (d) 提供 概念证明 SIRT3-FoxO3a 信号通路的激活可促进纤维化消退，从而导致 进行性肺部疾病的新治疗方法。