Apoptosis and Life-Long Caloric Restriction

描述(由申请人提供)：细胞凋亡是一种高度调节的细胞死亡形式，其特征是特定的形态、生化和分子事件。然而，它在衰老过程中的作用，特别是在有丝分裂后组织，如脑、心脏和骨骼肌中的作用还没有得到深入的研究。随着年龄的增长，有丝分裂后组织中的细胞凋亡似乎增加，这可能是观察到的组织功能随年龄增加而丧失的一个主要因素。随着年龄的增长和可能保护细胞凋亡的适应，诱导细胞凋亡的机制仍有待确定。氧化剂和钙启动了一系列事件，这些事件在线粒体和内质网介导的细胞死亡途径的激活中发挥关键作用。我们将内源性增加线粒体超氧阴离子自由基的水平，并外源性增加过氧化氢、过氧亚硝酸根和/或钙到年轻(6月龄)和老年(24月龄)大鼠的分离线粒体。通过阿霉素(增加线粒体超氧化物歧化)和thapsigargin(刺激内质网钙释放)，在幼年和老年大鼠体内，将研究线粒体和内质网介导的途径的激活和适应潜力，从而增加细胞凋亡。此外，我们将通过研究急性激活的调控细胞凋亡的调节蛋白，来确定6、12、18、24和26月龄Fischer 344大鼠在正常衰老过程中的细胞凋亡和凋亡信号转导通路激活的变化。我们将使用卡路里限制-一种减少氧化剂产生、改善钙处理、减少细胞损失和延长最大寿命的干预措施-来进一步研究抗细胞凋亡的适应。此外，我们将研究骨骼肌和心肌的功能与年龄的关系，并将其与细胞凋亡和热量限制对细胞凋亡的抑制有关。这一方法将有助于更好地理解幼年和老年动物急性应激、正常衰老和热量限制期间体内细胞凋亡的机制。

DESCRIPTION (provided by applicant): Apoptosis is a highly regulated form of cell death characterized by specific morphological, biochemical, and molecular events. However, its role during aging, particularly in post mitotic tissues such as the brain, heart and skeletal muscle has not been studied in depth. Apoptosis appear to increase in post-mitotic tissues with age and it may be a major contributing factor to the observed loss in tissue function with age. The mechanisms by which apoptosis are induced with advancing age and adaptations that may protect against apoptosis remain to be identified. Oxidants and calcium initiate a sequence of events that play a key role in the activation of the mitochondrial - and the endoplasmic reticulum-mediated pathways of cell death. We will endogenously increase levels of mitochondrial superoxide radical and also exogenously add hydrogen peroxide, peroxynitrite and/or calcium to isolated mitochondria in young (6-month) and old (24-month) rats. The activation and adaptive potential of the mitochondrial-mediated pathway and endoplasmic reticulum -mediated pathway will be investigated in vivo, in young and old rats, through the administration of both doxorubicin (increases mitochondrial superoxide) and thapsigargin (stimulates calcium release from the endoplasmic reticulum), causing an increase in apoptosis. Moreover, we will determine apoptosis and alterations in the activation of the apoptotic signal transduction pathways during normal aging, in 6-, 12-, 18-, 24- and 26-month old Fischer 344 rats, by studying regulatory proteins acutely activated to regulate apoptosis. We will use caloric restriction - an intervention that reduces oxidant production, improves calcium handling, reduces cell loss and extends maximum life span - to further study the anti-apoptotic adaptations. In addition, we will investigate skeletal and heart muscle function with age and relate this to apoptosis and the attenuation of apoptosis by caloric restriction. This approach will enable a greater understanding of the mechanisms of apoptosis in vivo during acute stress in young and old animals, normal aging, and caloric restriction.