Neuroprotective Gene Therapy in the Brain of Senile Rats

描述（由申请人提供）：阿根廷城市地区老年人口的增长与许多北美和欧洲城市相当。因此，与年龄有关的神经系统疾病的发病率正在成为对该国产生重大医疗和经济影响的问题。不幸的是，研究和开发神经退行性疾病的新治疗工具，如基因治疗，在该国实际上仍然没有发展起来。在这种背景下，本研究的总体目标是利用神经胶质细胞系来源的神经营养因子（GDNF）和胰岛素样生长因子I （IGF-I）这两种临床兴趣日益浓厚的神经保护分子的基因，在衰老大鼠的大脑中实施神经营养因子基因治疗。使用衰老大鼠作为与年龄相关的运动和认知功能下降的动物模型，一方面，我们希望继续与Martha Bohn博士合作研究GDNF和IGF-I拯救功能失调的中枢多巴胺能（DA）神经元的能力，建立在NIA和FIC授予PI的R21资助的基础上。其次，我们希望进一步开展与William Sonntag博士合作于2006年开始的关于IGF-I基因递送对衰老大鼠认知功能恢复能力的探索性研究。具体而言，我们建议：1)在老年（24个月）雌性大鼠下丘脑（HPTL）中实施长期GDNF基因治疗，这是一种成熟的年龄相关DA神经元功能障碍模型；2)确定GDNF和IGF-I基因联合治疗老年大鼠HPTL是否比单一营养因子基因递送更有效的神经保护作用。3)评价igf - 1基因治疗对老年（30月龄）雌性大鼠黑质DA神经元的神经保护作用。该治疗旨在逆转帕金森病（PD）动物模型中黑质DA神经元的显著丧失。4)实施外周（肌肉注射）IGF-I基因治疗，旨在提高衰老大鼠血清IGF-I水平，从而改善其海马依赖性认知功能。腺相关和腺病毒载体将用于基因传递到适当的目标区域。这些处理对DA神经元群体的影响将以形态计量学的方式进行评估。下丘脑和黑质DA功能将分别通过测定血清催乳素和进行运动试验来确定。受益于非常老的大鼠（一种独特的自发性DA神经元丢失模型）在国外的可用性，拟议的工作将集中在与年龄相关的神经退行性病理（PD）以及与年龄相关的认知能力下降，从而解决NIA的两个感兴趣的领域。该项目也是多学科的（该PAR鼓励的一个特点），包括神经内分泌学，认知神经科学和生物技术领域。公共卫生相关性：现代医学提高了预期寿命，导致老年痴呆症和帕金森氏症等与年龄有关的神经退行性疾病的发病率逐步上升，对认知和其他脑功能造成破坏性后果。在这种背景下，新的生物技术策略，如基因治疗和有效的神经保护分子，如胶质细胞系衍生的神经营养因子和胰岛素样生长因子I，成为预防和治疗这些破坏性病理的有希望的治疗工具。

DESCRIPTION (provided by applicant): The increase of the elderly population in the urban areas of Argentina is comparable to that of many North American and European cities. Consequently, the incidence of age-related neurological pathologies is becoming a problem of significant medical and economic impact for the country. Unfortunately, research and development of novel therapeutic tools for neurodegenerative diseases, like gene therapy, remain virtually undeveloped in the country. In this context, the overall goal of the present proposal is to implement neurotrophic factor gene therapy in the brain of aging rats, using the genes for glial cell line-derived neurotrophic factor (GDNF) and insulin-like growth factor I (IGF-I), two neuroprotective molecules of growing clinical interest. Using the aging rat as an animal model of age- related decline in motor and cognitive function, we wish, on the one hand, to continue our collaborative studies with Dr. Martha Bohn on the ability of GDNF and IGF-I to rescue dysfunctional central Dopaminergic (DA) neurons, building on the results generated during an R21 grant awarded by the NIA and FIC to the PI. Secondly, we wish to further develop the exploratory studies started in 2006 in collaboration with Dr. William Sonntag, on the restorative ability of IGF-I gene delivery on cognitive function in aging rats. Specifically, we propose: 1) to implement long-term GDNF gene therapy in the hypothalamus (HPTL) of old (24 mo.) female rats, a well-established model of age-related DA neuron dysfunction; 2) To determine whether combined GDNF and IGF-I gene therapy in the HPTL of senile rats results in a more effective neuroprotection than single trophic factor gene delivery. 3) To assess the neuroprotective activity of IGF-I gene therapy on the nigral DA neurons of senile (30 mo.) female rats. The treatment is intended to reverse the marked loss of nigral DA neurons in this animal model of Parkinson's disease (PD). 4) To implement peripheral (intramuscular) IGF-I gene therapy aimed at increasing serum IGF-I levels in aging rats which is expected to lead to an amelioration of their reduced hippocampal-dependent cognitive functions. Adeno associated and adenoviral vectors will be used for gene delivery to the appropriate target areas. The effects of the treatments on DA neuron populations will be assessed morphometrically. Hypothalamic and nigral DA function will be determined by measuring serum prolactin and performing motor tests, respectively. Profiting from the availability of very old rats (a unique model of spontaneous DA neuron loss) at the foreign site, the proposed work will focus on a relevant age-related neurodegenerative pathology (PD) as well as on age-related cognitive decline, thus addressing two areas of interest for the NIA. The project is also multidisciplinary (a feature encouraged by this PAR), encompassing the fields of neuroendocrinology, cognitive neuroscience and biotechnology. PUBLIC HEALTH RELEVANCE: The increase in life expectancy achieved by modern medicine has led to a progressive rise in the incidence of age-related neurodegenerative diseases like Alzheimer's and Parkinson's, with their destructive consequences on cognition and other brain functions. In this context, new biotechnological strategies like gene therapy and potent neuroprotective molecules like glial cell line-derived neurotrophic factor and insulin-like growth factor I, emerge as promising therapeutic tools for the prevention and treatment of these devastating pathologies.