Vasoprotection by Caloric Restriction Mimetics in Aging

描述(由申请人提供)：这是比森职业发展奖的申请，旨在为安娜·西西扎博士提供与雷诺俄克拉荷马老龄中心的神经认知功能相关的额外培训。西西扎博士是一位杰出的、出版广泛的候选人，额外的培训将提供行为分析、神经体视学和脑血管分析方面的专业知识，这是她获得独立所必需的。即使在没有明显病理过程的情况下，认知功能也会随着年龄的增长而下降。这种认知功能的下降明显降低了生活质量，是丧失独立性的一个主要因素，并给整个社会，特别是医疗保健系统带来了昂贵的负担。先前的研究表明，与年龄相关的脑血管稀疏和微血管功能障碍损害了海马区的血流，这在衰老过程中认知能力下降的病因中起到了作用。这项建议的目标是确定关键的细胞机制，这些机制可以在治疗上有针对性地预防/逆转与年龄相关的脑微血管改变，维持正常的海马区血流，并保护神经认知功能。这一应用的方向和假设来自关键发现，即卡路里限制(CR)和CR类似物白藜芦醇有可能有益于老年哺乳动物的血管生理学。我们建议通过诱导Nrf2/ARE调节的ROS解毒系统来检验这一假设，即热量限制通过诱导Nrf2/ARE调节的ROS解毒系统来保护大脑微血管免受与衰老相关的氧化应激的有害影响。我们假设，在内皮细胞(白藜芦醇或萝卜硫醚)中对这一途径的药理激活与热量限制的效果相似，这对保护衰老期间的神经认知功能具有重要的干预策略。研究的目的如下：1)评估CR和CR模拟物是否能够延缓/防止与年龄相关的脑局部血流量下降、毛细血管密度和微血管生成减少以及空间学习和记忆能力下降，并确定NRF2基因缺失是否取消了CR和白藜芦醇治疗的微血管保护作用。2)确定CR和CR模拟物是否可以通过诱导Nrf2/ARE依赖的抗氧化系统来延缓/预防与年龄相关的微血管氧化应激和局部血管调节机制的损伤。3)确定老年动物CR诱导的全身因素对脑微血管内皮细胞是否具有抗氧化、抗凋亡和促血管生成作用。培养的内皮细胞将用自由或CR喂养的动物的血清处理，并将评估细胞ROS的产生、血管生成潜力和对氧化应激诱导的细胞凋亡的抵抗力。Nrf2的激活在CR血清处理的保护作用中的作用将被阐明。这项拟议的研究将首次全面分析Nrf2/ARE通路在CR期间维持年轻脑微血管表型中的作用，并将为预防/逆转脑血管功能障碍和脑功能变化的新方法提供新的明确信息，这些功能变化是年龄相关疾病、认知功能丧失和痴呆症风险增加的先兆。 公共卫生相关性：认知功能的下降明显降低了生活质量，是丧失独立性的一个主要因素，并给整个社会，特别是医疗保健系统带来了昂贵的负担。老年性脑供血障碍是老年人认知功能减退的重要原因。本项目的目标是寻找新的分子靶点，这些靶点可以被药物激活以保护脑血管免受自由基介导的损伤，从而改善老年患者的脑血流和认知功能。我们将测试这样的假设，即在血管系统中，一种名为NRF2的蛋白质介导了多方面的血管保护作用。我们推测，使用Nrf2激活分子治疗，或通过饮食限制诱导Nrf2，可以发挥显著的脑血管保护作用，保护老年小鼠的认知功能。

DESCRIPTION (provided by applicant): This is Beeson Career Development Award application designed to provide Dr. Anna Csiszar with additional training related to neurocognitive function at the Reynolds Oklahoma Center on Aging. Dr. Csiszar is an outstanding, well published candidate and the additional training will provide expertise in behavioral analyses, neurostereology, and cerebrovascular analyses necessary for her to achieve independence. Cognitive function decreases with age even in the absence of overt pathological processes. This decline in cognitive function clearly diminishes quality of life, is a major factor in loss of independence, and imparts a costly burden to society as a whole and to the medical health care system in particular. Previous studies demonstrated that age-related cerebrovascular rarefaction and microvascular dysfunction impair hippocampal blood flow, which has an etiologic role in cognitive decline during aging. The goal of this proposal is to identify key cellular mechanisms that can be targeted therapeutically to prevent/reverse age-related cerebral microvascular alterations maintaining normal hippocampal blood flow and protecting neurocognitive function. The direction and hypotheses of this application emerge from key findings that caloric restriction (CR) and the CR mimetic resveratrol have the potential to beneficially impact vascular physiology in aged mammals. We propose to test the hypothesis that caloric restriction protects the cerebral microvasculature from the deleterious effects of oxidative stress associated with aging, via induction of the Nrf2/ARE- regulated ROS detoxification systems. We posit that pharmacological activation of this pathway in endothelial cells (with resveratrol or sulforaphane) mimics the effects of caloric restriction, which contribute significantly to an intervention strategy for protection of neurocognitive function during aging. The following aims are proposed: 1) Assess whether CR and CR mimetics can delay/prevent the age-associated decline in cerebral regional blood flow, the reduction in capillary and arteriolar density and angiogenesis, and the decline in spatial learning and memory and determine whether genetic depletion of Nrf2 abrogates the microvascular protective effects of CR and resveratrol treatment. 2) Determine whether CR and CR mimetics can delay/prevent age-associated microvascular oxidative stress and impairment of local vasoregulatory mechanisms via induction of Nrf2/ARE-dependent antioxidant systems. 3) Determine whether systemic factors induced by CR in aged animals confer anti-oxidative, anti-apoptotic and pro-angiogenic effects on cerebral microvascular endothelial cells. Cultured endothelial cells will be treated with sera from ad libitum or CR fed animals and cellular ROS production, angiogenic potential and resistance to oxidative stress-induced apoptosis will be assessed. The role of Nrf2 activation in the protective effects of CR sera treatment will be elucidated. The proposed studies will provide the first comprehensive analysis of the role of the Nrf2/ARE pathway in maintaining a youthful cerebral microvascular phenotype during CR and will provide novel and definitive information on novel approaches to prevent/reverse cerebrovascular dysfunction and functional changes in the brain with age that are precursors to age-related disease, loss of cognitive function and the increased risk of dementia. PUBLIC HEALTH RELEVANCE: A decline in cognitive function clearly diminishes quality of life, is a major factor in loss of independence, and imparts a costly burden to society as a whole and to the medical health care system in particular. The age-related impairment of cerebral blood supply significantly contributes to cognitive decline in the elderly. The goal of this project is to identify novel molecular targets that can be activated pharmacologically to protect the cerebral blood vessels from free radical mediated injury and thus to improve cerebral blood flow and cognitive function in elderly patients. We will test the hypotheses that in the vascular system a protein named Nrf2 mediates multifaceted vasoprotective effects. We posit that treatment with Nrf2-activating molecules, or inducing Nrf2 by dietary restriction can exert significant cerebral vasoprotective effects protecting cognitive function in aged mice.