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.

人类纤维化疾病会影响许多器官系统，包括心脏，血管，肾脏，肝脏和肺， 在美国，包括我们的退伍军人管理（VA）患者中的伯恩（Burnen）过多的疾病 人口。最常见的纤维化肺疾病，特发性肺纤维化（IPF）的特征是 肺实质的过度疤痕组织形成和不可逆转的破坏，导致气体交换 异常和最终呼吸衰竭。衰老是IPF的强大风险因素；但是， 解释与年龄相关的纤维化疾病预测的细胞/分子机制仅是 开始探索。对衰老在这种疾病中的作用的了解将有助于 开发具有更高临床效率的新型疗法。 为了支持此VA优异奖裁定申请，我们为我们的几项贡献做出了一些贡献 了解肺损伤和修复机制中的衰老机制。具有IPF表达的人类受试者 线粒体sirtuin的低水平，SIRT3，在肌纤维细胞中，在从IPF中分离出的Ex-Vivo成纤维细胞中 肺。 SIRT3的这种下调在小鼠的非分辨纤维化衰老模型中得到了复制。尽管 小鼠的纤维化大部分在微观霉素后2-4个月以内，老年小鼠表现出持续的纤维化。 我们的数据表明，年轻小鼠的纤维化解决能力与SIRT3的恢复有关 在肺损伤的晚期恢复阶段的水平，而老年小鼠则不存在。但是，重新构身 SIRT3（通过肺靶向非病毒cDNA质粒递送）恢复了老年纤维化的能力 老鼠。这种受保护的效果与FoxO3a的体内激活有关，这是由较高水平的 核FOXO3A。细胞感应和促纤维细胞因子都会转化生长因子-β1（TGF- β1）诱导SIRT3和FOXO3A的下调，导致线粒体功能障碍的事件， 肺成纤维细胞的衰老和凋亡抗性。我们的研究还支持 肺泡巨噬细胞中SIRT3的调节调节旁分泌的FOXO3A的成纤维细胞激活 机制。另外，组蛋白乙酰转移酶P300和环状AMP反应元件结合 蛋白（CREB）结合蛋白（CBP）在TGF-β1对SIRT3的表观下调中暗示 和细胞感应。 SIRT3-FOXO3A信号轴的激活受损会促进感觉和 抗细胞凋亡的成纤维细胞表型，可驱动持续/非分辨纤维化。 该赠款提案中要检验的中心假设是持续/非分辨纤维化 与衰老有关 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，感应和凋亡抗性。 我们的具体目的是：（1）阐明肺中SIRT3的P300/CBP依赖性表观遗传调节 介导促分辨率表型的成纤维细胞和肺泡巨噬细胞； （2）调查 SIRT3-FOXO3A信号轴恢复线粒体生物能和凋亡易感性 感觉/纤维化肺成纤维细胞； （3）确定SIRT3是否重建 遗传/药理学方法通过激活FOXO3A在老年小鼠中促进纤维化的分辨率 肺成纤维细胞。该提案中目标的完成将：（a）发现表观遗传机制 用细胞感应/衰老来控制SIRT3表达； （b）提供机械洞察的作用 SIRT3-FOXO3A信号传导在线粒体生物能和细胞塑性/命运的调节中； （c） 阐明巨噬细胞 - 纤维细胞串扰和SIRT3调节促巨噬细胞； （d）提供 概念证明SIRT3-FOXO3A信号通路的激活促进了纤维化的分辨率， 采用新的治疗方法进行进行性肺部疾病。