Sirtuins in Lung Aging and Fibrosis

Sirtuins 在肺衰老和纤维化中的作用

• 批准号: 9210543
• 负责人: Victor J. Thannickal
• 金额: --
• 依托单位: BIRMINGHAM VA 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: 2016-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9210543
• 关键词: Accounting; Acetylation; Affect; Age; Aging; Animals; Apoptosis; Applications Grants; Bioenergetics; Biological; Bleomycin; Blood Vessels; Cell Aging; Cells; Cicatrix; Clinical; Collagen; DNA Methylation; Data; Development; Diagnosis; Disease; Down-Regulation; Enzymes; Epigenetic Process; Equilibrium; Fibroblasts; Fibrosis; Gases; Genes; Genetic; Hamman-Rich syndrome; Heart; Human; Immunohistochemistry; Incidence; Kidney; Knock-out; Laboratories; Link; Liver; Lung; Lung diseases; Maintenance; Mediating; Mesenchymal; Mitochondria; Mitochondrial Proteins; Modeling; Molecular; Morbidity - disease rate; Mus; Myofibroblast; NADPH Oxidase; Oxidation-Reduction; Pathogenesis; Pharmaceutical Preparations; Phase; Phenotype; Pirfenidone; Population; Prevalence; Pulmonary Fibrosis; Reactive Oxygen Species; Resistance; Resolution; Respiratory Failure; Role; Signal Transduction; Sirtuins; Structure of parenchyma of lung; Survival Rate; Testing; Time; Tissues; United States; United States Department of Veterans Affairs; age related; aged; body system; burden of illness; clinical efficacy; fibrogenesis; histone modification; human subject; improved; in vivo; insight; lung injury; mitochondrial dysfunction; mortality; mouse model; novel; novel therapeutic intervention; novel therapeutics; older patient; public health relevance; response; senescence

 DESCRIPTION (provided by applicant) Idiopathic pulmonary fibrosis (IPF) is a disease of aging. IPF carries a high morbidity and mortality, with a median survival rate of less than three years. The incidence and prevalence of IPF increase drastically with age; however, despite this strong association, cellular/molecular mechanisms that account for the aging predilection to fibrotic disease have not been elucidated. Recent studies from our laboratory have identified a reactive oxygen species (ROS)-generating enzyme, NADPH oxidase-4 (Nox4), in mediating differentiation of fibroblasts (Fbs) to myofibroblasts (MFbs), key effectors of fibrogenesis, and in in-vivo lung fibrosis in murine models of lung injury. Our preliminary studies indicate that the biological actions of Nox4 may be modulated by the expression of SIRT3, a mitochondrial sirtuin. Both cellular senescence and TGF-β1 mediate suppression of SIRT3; our preliminary studies support a role for epigenetic silencing of SIRT3 involving both DNA methylation and histone modification. Decreased expression of SIRT3 promotes a senescent and pro-fibrotic Fb phenotype. TGF-β1-induced down-regulation of SIRT3 is associated with hyper-acetylation of mitochondrial proteins, supporting a role for altered mitochondrial bioenergetics in MFbs. Human subjects with IPF express low levels of SIRT3 in myofibroblastic foci (by immunohistochemistry), as well as in ex-vivo Fbs isolated from IPF lungs. We have developed a novel aging model of non-resolving fibrosis in mice; fibrosis in young mice (2 months) resolves by >50% by 4 months post-bleomycin, whereas aged mice (18 months) show persistent fibrotic response. While SIRT3 levels decrease during the fibrogenic phase in both groups, young mice demonstrate a capacity to recover SIRT3 levels during resolution; in contrast, aged mice manifest sustained down-regulation of SIRT3. The central hypothesis to be tested in this grant proposal is that, in the context of aging, lung injury results in sustained, epigenetically-regulated SIRT3 silencing that leads to mitochondrial dysfunction, MFb senescence and apoptosis resistance, leading to persistent fibrosis with aging. Our specific aims are to: (1) determine epigenetic mechanisms for SIRT3 down-regulation with cellular senescence and with TGF-β1 signaling in lung Fbs; (2) determine the role of SIRT3 in regulating mitochondrial bioenergetics, Fb senescence and apoptosis resistance; (3) determine whether whole-animal SIRT3 knockout and/or conditional genetic deletion of SIRT3 in collagen-producing/mesenchymal cells induce(s) persistent fibrosis in young mice. The completion of the Aims in this proposal will: (a) elucidate epigenetic mechanisms that control SIRT3 expression with cellular senescence/aging; (b) provide mechanistic insights into the role of SIRT3 in maintenance of mitochondrial bioenergetics and cellular plasticity/fate; (c) provide proof-of-concept that SIRT3 induction in the context of age-associated fibrosis facilitates fibrosis resolution, uncovering a novel therapeutic approach to non-resolving fibrotic disorders such as IPF.

 描述（由申请人提供） 特发性肺纤维化（IPF）是衰老的疾病。 IPF具有高发病率和死亡率，中位生存率不到三年。 IPF的事件和患病率随着年龄的增长而大大增加；然而，尚未阐明这种解释纤维性疾病衰老预测的强大关联，细胞/分子机制。我们实验室的最新研究确定了活性氧（ROS）生成酶，NADPH氧化酶4（NOX4），在介导成纤维细胞（FBS）与肌纤维细胞（MFBS）的分化中，纤维发生的关键影响，纤维发生的关键作用，在穆林（Murine Inbuline in-Vivo）纤维纤维中的MURINE损伤中。我们的初步研究表明，NOX4的生物学作用可以通过线粒体Sirtuin的Sirt3的表达来调节。细胞感应和TGF-β1均介导SIRT3的抑制作用；我们的初步研究表明，NOX4的生物学作用可以通过线粒体Sirtuin的Sirt3的表达来调节。初步研究支持SIRT3表观遗传沉默的作用，涉及DNA甲基化和组蛋白修饰。 SIRT3的表达降低会促进感官和纤维化的FB表型。 TGF-β1诱导的SIRT3下调与线粒体蛋白的过度乙酰化有关，这支持了MFBS中线粒体生物能量改变的作用。具有IPF的人类受试者在肌纤维细胞灶中表达低水平的SIRT3（通过免疫组织化学）以及从IPF肺部分离的前体体FB中。我们已经开发了一种新型的小鼠纤维化衰老模型。小鼠的纤维化（2个月）在珠霉素后4个月降低了> 50％，而老年小鼠（18个月）显示持续的纤维化反应。尽管两组的纤维化阶段中的SIRT3水平降低，但幼鼠表现出在分辨率期间恢复SIRT3水平的能力。相反，老年小鼠表现出SIRT3的下调。该赠款提案中要检验的中心假设是，在衰老的背景下，肺损伤导致持续的表观遗传调节的SIRT3沉默导致线粒体功能障碍，MFB感应和凋亡性抗性，导致持续的纤维化与衰老。我们的具体目的是：（1）确定SIRT3下调的表观遗传机制，具有细胞感应和肺FBS中的TGF-β1信号传导； （2）确定SIRT3在控制线粒体生物能，FB感应和凋亡耐药性中的作用； （3）确定在产生胶原蛋白的/间充质细胞中SIRT3的全动物SIRT3基因敲除和/或条件遗传缺失是否诱导了年轻小鼠的持续性纤维化。该提案中目标的完成将：（a）阐明用细胞感应/衰老控制SIRT3表达的表观遗传机制； （b）提供了SIRT3在维持线粒体生物能和细胞塑性/命运中的作用的机械见解； （C）提供了概念验证，即SIRT3在与年龄相关的纤维化背景下诱导促进纤维化的分辨率，从而发现了一种新型的热方法，用于非分辨纤维化疾病，例如IPF。