Anti-aging and anti-cancer effects of thioredoxins

硫氧还蛋白的抗衰老和抗癌作用

• 批准号: 8452588
• 负责人: YUJI IKENO
• 金额: --
• 依托单位: SOUTH TEXAS VETERANS HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8452588
• 关键词: Address; Age-Months; Aging; Aging-Related Process; Antioxidants; Attenuated; Breeding; Cell Nucleus; Cells; Cytosol; Data; Disease; Disulfides; Down-Regulation; Environment; Enzymes; Functional disorder; Goals; Human; Hydrogen; Knock-out; Knockout Mice; Longevity; Malignant Neoplasms; Measures; Mitochondria; Mus; Outcome; Oxidation-Reduction; Oxidative Stress; Pathology; Physiological; Play; Population; Production; Reaction; Reactive Oxygen Species; Reducing Agents; Role; Seminal; Signal Transduction; Source; Sulfhydryl Compounds; Testing; Thioredoxin; Time; Tissues; Transgenic Mice; Transgenic Organisms; Wild Type Mouse; age effect; age related; anti aging; attenuation; catalase; end of life; interest; middle age; offspring; overexpression; oxidative damage; prevent; protein function

DESCRIPTION (provided by applicant): Thioredoxin (Trx) was first recognized in the early 1960s as the reductant used by a variety of enzymes. Two Trxs have been identified in various species including humans, one cytosolic (Trx1) and one mitochondrial (Trx2). Trx was first identified as a hydrogen donor for enzymes involved in reductive reactions. However, the Trxs also play an important role in maintaining the reduced environment in the cells through thiol- disulfide exchange reactions, which is ideally suited to control protein function via the redox state of structural or catalytic SH groups. Therefore, the Trxs could play an anti-aging action either through their ability to reduce the leve of oxidative stress/damage or through alterations in redox-sensitive signaling, which has diverse effects on pathophysiology. Over the past three years, we have conducted the first detailed study on the effect of overexpressing or down-regulating Trx1 or Trx2 on aging. Interestingly, we found that the Trx2Tg mice that overexpress Trx2 in all tissues during aging showed a significant extension of lifespan (25.6%) compared to wild-type mice, although we did not observe a significant increase in survival of the Trx1Tg mice, when the Trx1 overexpression was maintained over the lifespan. The extension of lifespan of Trx2Tg mice was correlated to less reactive oxygen species (ROS) production from mitochondria and less oxidative stress. These data indicate that overexpressing Trx in the mitochondria may be more important than in the cytosol on aging because mitochondria are a major source of ROS. When we tested the effects of reduced levels of thioredoxin in cytosol or mitochondria on aging, we surprisingly observed the reversed effects, i.e., a significant increase in survival of the Trx1KO mice (12.6%) compared to wild-type mice while the Trx2KO mice showed little effects on lifespan. The extension of lifespan of Trx1KO mice was associated with fewer cancers compared to wild-type mice at 22-24 months of age. These data indicate that reduced cancer in the Trx1KO mice could be one of the contributing factors of extended lifespan. These interesting observations led us to these two questions: 1) Do the Trx2Tg x Trx1KO mice, which increase Trx2 in mitochondria and reduce Trx1 in cytosol, show additive anti- aging effects; and 2) Do overexpression of Trx2 and/or downregulation of Trx1 attenuate age-related pathology? The goal of this application is to address these two questions by using transgenic mice that overexpress Trx2, heterozygous knockout (KO) mice that down-regulate Trx1, and their offspring that increase Trx2 in mitochondria and reduce Trx1 in cytosol (Trx2Tg x Trx1KO mice). Using these mice, we will test the following hypothesis: overexpression of thioredoxin in mitochondria (Trx2) along with down-regulation of thioredoxin in cytosol (Trx1) will show a greater extension of lifespan and a greater reduction in age- related pathology compared to the overexpressing Trx2 or down-regulating Trx1 alone, and the extension of lifespan will occur because of additive effects of independent mechanisms, i.e., protection against oxidative stress/damage in mitochondria and attenuation of pathology, e.g., cancer. Specific Aim 1: To measure the effect of overexpressing Trx2 and/or down-regulating Trx1 on aging and age- related physiological changes in mice. Specific Aim 2: To measure the effect of overexpressing Trx2 and/or down-regulating Trx1 on age-related pathology in mice. Specific Aim 3: To measure the effect of overexpressing Trx2 and/or down-regulating Trx1 on the antioxidant status, the age-related accumulation of oxidative damage, the mitochondria function and the reactive oxygen species production, and the redox status in various tissues of mice. Specific Aim 4: To measure the effect of overexpressing Trx2 and/or down-regulating Trx1 on redox-sensitive signaling in various tissues of mice.

描述(由申请人提供)： 硫氧还蛋白(Trx)在20世纪60年代初首次被认为是各种酶使用的还原剂。在包括人类在内的不同物种中已经发现了两个Trxs，一个是胞质的(Trx1)，另一个是线粒体的(Trx2)。Trx首先被确定为参与还原反应的酶的供氢体。然而，Trxs也在通过硫醇-二硫键交换反应维持细胞内还原环境方面发挥着重要作用，这非常适合于通过结构或催化SH基团的氧化还原状态来控制蛋白质的功能。因此，Trxs可能通过降低氧化应激/损伤水平或通过改变氧化还原敏感信号发挥抗衰老作用，而氧化还原敏感信号对病理生理有不同的影响。在过去的三年里，我们首次详细研究了Trx1或Trx2的过度表达或下调对衰老的影响。有趣的是，我们发现在衰老过程中在所有组织中过表达Trx2的Trx2Tg小鼠与野生型小鼠相比，寿命显著延长(25.6%)，尽管我们没有观察到Trx1Tg小鼠的存活率显著增加，当Trx1过表达持续到整个寿命。Trx2Tg小鼠寿命的延长与线粒体产生的活性氧物种(ROS)减少和氧化应激减少有关。这些数据表明，在衰老过程中，线粒体中TRX的过度表达可能比胞浆中的TRX过表达更重要，因为线粒体是ROS的主要来源。当我们测试细胞质或线粒体中硫氧还蛋白水平降低对衰老的影响时，我们意外地观察到相反的效果，即Trx1KO小鼠的存活率(12.6%)显著高于野生型小鼠，而Trx2KO小鼠的寿命几乎没有影响。与22-24个月大的野生型小鼠相比，Trx1KO小鼠寿命的延长与较少的癌症有关。这些数据表明，Trx1KO小鼠的癌症减少可能是延长寿命的因素之一。这些有趣的观察让我们提出了这两个问题：1)Trx2Tg x Trx1KO小鼠，增加线粒体中的Trx2，减少胞浆中的Trx1，是否显示出相加的抗衰老作用；2)Trx2的过度表达和/或Trx1的下调是否减轻了与年龄相关的病理？这项应用的目标是通过使用过度表达Trx2的转基因小鼠、下调Trx1表达的杂合敲除(KO)小鼠及其后代(Trx2Tg x Trx1KO小鼠)来解决这两个问题。利用这些小鼠，我们将检验以下假设：与单独过度表达Trx2或下调Trx1相比，线粒体中硫氧还蛋白(Trx2)的过度表达以及胞浆中硫氧还蛋白(Trx1)的下调将显示出更大的寿命延长和年龄相关病理的减少，并且寿命的延长将是由于独立机制的相加作用，即保护线粒体免受氧化应激/损伤和减轻病理，如癌症。具体目的1：研究Trx2基因过表达和/或Trx1基因下调对小鼠衰老及衰老相关生理变化的影响。特定目的2：检测Trx2过表达和/或下调Trx1对小鼠年龄相关病理的影响。具体目的3：检测Trx2过表达和/或下调Trx1对小鼠不同组织中抗氧化状态、氧化损伤的年龄积累、线粒体功能和活性氧产生以及氧化还原状态的影响。特异目的4：检测过表达Trx2和/或下调Trx1对小鼠不同组织中氧化还原敏感信号的影响。