Apoptosis and Life-Long Caloric Restriction

描述（由申请人提供）：细胞凋亡是一种高度调控的细胞死亡形式，其特征是特定的形态学、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，如大脑、心脏和骨骼肌中的作用尚未得到深入研究。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丧失的主要因素。随着年龄的增长而诱导细胞凋亡的机制以及可能防止细胞凋亡的适应性仍有待确定。氧化剂和钙启动一系列事件，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。我们将内源性地增加线粒体超氧自由基的水平，并外源性地将过氧化氢、过氧亚硝酸盐和/或钙添加到年轻（6个月）和老年（24个月）大鼠的分离线粒体中。将通过给予阿霉素（增加线粒体超氧化物）和毒胡萝卜素（刺激内质网钙释放），在年轻和年老大鼠体内研究线粒体介导途径和内质网介导途径的激活和适应潜力，从而导致细胞凋亡增加。此外，我们将通过研究急性激活调节细胞凋亡的调节蛋白，确定 6、12、18、24 和 26 个月大 Fischer 344 大鼠正常衰老过程中的细胞凋亡和细胞凋亡信号转导途径激活的变化。我们将使用热量限制（一种减少氧化剂产生、改善钙处理、减少细胞损失并延长最大寿命的干预措施）来进一步研究抗凋亡适应。此外，我们将研究骨骼和心肌功能随年龄的变化，并将其与细胞凋亡和热量限制减弱细胞凋亡联系起来。这种方法将有助于更好地了解年轻和年老动物在急性应激、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.