SIRT6 as a novel therapeutic target in aging and age-related osteoarthritis

SIRT6 作为衰老和年龄相关骨关节炎的新型治疗靶点

• 批准号: 10303788
• 负责人: John A Collins
• 金额: $ 7.8万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-30 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10303788
• 关键词: Acceleration; Affect; Age; Aging; Antioxidants; Apoptosis; Attenuated; Binding; Biosensor; Cartilage; Chondrocytes; Chromatin; Co-Immunoprecipitations; Complex; DNA Damage; Data; Deacetylase; Degenerative polyarthritis; Development; Disease; Enzymes; Event; Functional disorder; Future; Gene Expression; Genes; Genetic Transcription; Goals; Homeostasis; Human; Hydrogen Peroxide; Hypoxia; Joints; Knock-out; Lead; Link; Longevity; MAPK8 gene; Maintenance; Measures; Mediating; Metabolic; Metabolic dysfunction; Metalloproteases; Mission; Mitogen-Activated Protein Kinases; Molecular; Mus; Nuclear; Obese Mice; Oxidation-Reduction; Oxidative Stress; Pathogenesis; Pathology; Pathway interactions; Phosphorylation; Phosphotransferases; Preventive therapy; Process; Promoter Regions; Proteins; Public Health; Reactive Oxygen Species; Reporter; Repression; Resistance; Reverse Transcriptase Polymerase Chain Reaction; Role; Sex Differences; Signal Pathway; Signal Transduction; Sirtuins; System; TXN gene; TXNIP gene; Therapeutic Intervention; Thioredoxin-2; Tissues; Woman; Work; age related; aged; aggrecanase; cartilage degradation; catalyst; chromatin immunoprecipitation; clinical development; clinically relevant; defined contribution; disability; experimental study; healthspan; healthy aging; human female; human male; improved; in vivo; innovation; joint destruction; male; mouse model; new therapeutic target; overexpression; oxidative damage; p38 Mitogen Activated Protein Kinase; prevent; sex; small molecule; systemic inflammatory response; telomere; tool; transcription factor

Osteoarthritis (OA) is a leading cause of global disability, and disproportionally affects women. Understanding the precise mechanisms that drive age and sex-specific cartilage degeneration would greatly increase our fundamental understanding of OA pathogenesis and lead to the development of new disease modifying therapies. Recent evidence has identified the nuclear localized deacetylase, sirtuin 6 (SIRT6), as a master regulator of aging processes, in part through promoting resistance to oxidative stress. In mice, SIRT6 overexpression extends lifespan, but only in males, which raises the intriguing possibility that sex specific differences in SIRT6 function could regulate age-associated mechanisms that drive OA. Our preliminary data in chondrocytes demonstrates that SIRT6 activity declines with age, resulting in a significant increase in the levels of the pro-oxidant, thioredoxin (Trx) interacting protein (TXNIP). We propose that increasing levels of TXNIP exacerbate oxidative stress conditions by binding to, and inhibiting, the antioxidant protein, thioredoxin (Trx). A major function of Trx is to suppress catabolic redox signaling events through direct repression of apoptosis signal regulating kinase (ASK1). We have previously shown that ASK1 signaling prevents cartilage degeneration and leads to chondrocyte degeneration and age-associated OA. Thus, our central hypothesis is that aged chondrocytes treated with a SIRT6 activator will be protected from oxidative stress and catabolic signaling events that drive cartilage damage and promote OA. Aim 1 will assess if activation of SIRT6 with the small molecule activator, MDL-800, can mitigate nuclear-specific oxidative stress that will be generated and measured using the innovative NLS-HyPer-DAAO redox biosensor in chondrocytes derived from younger and older cartilage donors. To determine if the effects of SIRT6 are sex-specific, both Aims will use chondrocytes isolated from male and female human chondrocytes. To assess if SIRT6 directly attenuates oxidative stress induced chondrocyte damage, we will assess: 1) redox-related gene transcription, 2) antioxidant levels, 3) DNA damage and telomere dysfunction, and 4) transcription factor activity. Experiments will be conducted under both atmospheric (21%) and hypoxic (2%) conditions to define the contribution of O2 on these processes. In Aim 2, performing the same experiments described in Aim 1, we will determine how SIRT6 activation modulates oxidative stress signaling in chondrocytes through the SIRT6/TXNIP/Trx/ASK1 axis. To assess this, we will examine: 1) TXNIP-Trx and Trx- ASK1 complex formation, 2) ASK1 and MAP kinase activation, 3) gene expression of matrix degrading enzymes. Results from this project will define the specific mechanisms linking chondrocyte aging to OA pathogenesis and may provide significant evidence as to why this disease effects women at a higher rate. It will also provide preliminary data for a future R01 application aimed at determining how SIRT6 activation can be utilized in vivo as a therapy to slow or prevent the progression of OA. Ultimately, we expect this work to catalyze the discovery of new disease-modifying treatments that will reduce the physical hardships associated with age and OA.

骨关节炎（OA）是全球残疾的主要原因，对女性的影响尤其严重。理解 驱动年龄和性别特异性软骨退化的精确机制将大大增加我们的 对OA发病机制的基本了解，并导致新疾病的发展， 治疗最近的证据已经确定了核定位的脱乙酰酶，sirtuin 6（SIRT 6），作为一个主 调节衰老过程，部分通过促进抗氧化应激。在小鼠中，SIRT 6 过度表达延长寿命，但仅在男性中，这提出了有趣的可能性，性别特异性 SIRT 6功能的差异可以调节驱动OA的年龄相关机制。我们的初步数据， 软骨细胞表明SIRT 6活性随着年龄的增长而下降，导致SIRT 6水平的显著增加。 硫氧还蛋白（Trx）相互作用蛋白（TXNIP）。我们认为增加TXNIP水平 通过结合并抑制抗氧化蛋白硫氧还蛋白（Trx）来加剧氧化应激状况。一 Trx的主要功能是通过直接抑制凋亡信号来抑制分解代谢氧化还原信号传导事件 调节激酶（ASK 1）。我们之前已经证明，ASK 1信号可以防止软骨退化， 导致软骨细胞变性和年龄相关的OA。因此，我们的中心假设是， 用SIRT 6激活剂处理的软骨细胞将被保护免受氧化应激和分解代谢信号事件 导致软骨损伤和骨关节炎。目的1将评估是否用小分子活化SIRT 6 激活剂MDL-800可以减轻核特异性氧化应激，其将使用 创新的NLS-Hyper-DAAO氧化还原生物传感器在来自年轻和老年软骨供体的软骨细胞中的应用。 为了确定SIRT 6的作用是否是性别特异性的，两个目的都将使用从男性和女性分离的软骨细胞。 女性人类软骨细胞。为了评估SIRT 6是否直接减弱氧化应激诱导的软骨细胞 损伤，我们将评估：1）氧化还原相关的基因转录，2）抗氧化剂水平，3）DNA损伤和端粒 功能障碍，和4）转录因子活性。实验将在两个大气（21%） 和缺氧（2%）条件下，以确定这些过程中的O2的贡献。在目标2中，执行相同 在目标1中描述的实验中，我们将确定SIRT 6激活如何调节氧化应激信号传导。 软骨细胞通过SIRT 6/TXNIP/Trx/ASK 1轴。为了评估这一点，我们将检查：1）TXNIP-Trx和Trx- ASK 1复合物形成，2）ASK 1和MAP激酶激活，3）基质降解酶的基因表达。 该项目的结果将确定软骨细胞老化与OA发病机制的具体机制， 可能提供重要的证据，说明为什么这种疾病对妇女的影响更高。它还将提供 未来R 01应用的初步数据，旨在确定如何在体内利用SIRT 6激活 作为减缓或预防OA进展的疗法。最终，我们希望这项工作能够催化 新的疾病修饰治疗，将减少与年龄和OA相关的身体困难。