The role of Mnbk in Downs Syndrome brain development and aging

描述（由申请人提供）：我们建议整合分子生物学、形态测量学和临床研究，以确定导致唐氏综合征（DS）患者大脑发育异常、加速衰老和早发阿尔茨海默病的机制。 我们计划对44名DS患者的记忆系统（海马、杏仁核和内嗅皮层）和感觉运动系统（黑质、脚桥被盖核、尾板内丘脑、尾状核、壳核、苍白球、丘脑核、运动皮层和小脑）进行生化和形态计量学研究。由于所有DS患者均发生早发性AD，部分患者发生帕金森型神经变性，因此将DS中神经元丢失的机制与散发性AD（30例）、特发性PD（30例）和正常衰老（44例）中神经元变性和丢失的时间和地形图模式进行比较。 我们的目标将是确定：（1）Mnbk/DyrklA蛋白异常表达在DS患者记忆和运动系统发育神经元缺陷中的作用;（2）DS患者中Mnbk/Dyrk 1A蛋白过量引起的突触异常的机制;（3）DS患者中Mnbk/Dyrk 1A蛋白在40岁时大脑加速衰老中的作用;（4）不同的神经退行性变机制对40岁以上DS患者痴呆和运动退化的贡献;（5）与正常衰老、散发性AD和特发性PD相比，DS患者神经退行性变对神经元和功能丧失的贡献的改变。我们假设在DS中，Mnbk/Dyrk 1A基因的额外拷贝不仅是形成结构和功能发育异常的关键因素，而且还影响成年期突触的功能，有助于加速大脑衰老，并改变AD和PD病理学发展的结构和功能背景。我们假设，我们将能够确定AD和PD病理过程中的DS特异性修饰。本研究将为明确特定功能缺陷的发生机制和形态学基础提供依据，并有助于提高诊断和治疗水平。

DESCRIPTION (provided by applicant): We propose to integrate molecular biology, morphometry, and clinical studies to identify mechanisms leading to abnormal brain development, accelerated aging, and early onset of Alzheimer disease in people with Down syndrome (DS). We plan to conduct biochemical and morphometric studies of the memory system (hippocampus, amygdala, and entorhinal cortex) and sensory-motor system ( substantia nigra, pedunculopontine tegmental nucleus, caudal intralaminar thalamus, caudate nucleus, putamen, globus pallidus, nucleus accumbens, motor cortex, and cerebellum) in 44 people with DS. Because all people with DS develop early onset AD and some develop parkinsonian-type neurodegeneration, the mechanisms of neuronal loss in DS will be compared with temporal and topographic patterns of neuronal degeneration and loss in sporadic AD (30 cases), idiopathic PD (30 cases), and normal aging (44 cases). Our goal will be to determine: (1) the role of abnormal expression of Mnbk/DyrklA in developmental neuronal deficits in the memory and motor system of people with DS; (2) the mechanisms of synaptic abnormalities caused by excess of Mnbk/Dyrk1A protein in people with DS; (3) the role of Mnbk/Dyrk1A protein in brain accelerated aging during the fourth decade of life in people with DS; (4) the contribution of different mechanisms of neurodegeneration to dementia and motor deterioration in people with DS over 40 years of age; (5) modifications in the contribution of neurodegenerative changes to neuronal and functional loss in people with DS in comparison to normal aging, sporadic AD, and idiopathic PD. We hypothesize that in DS the extra copy of the Mnbk/Dyrk1A gene is not only a key factor in shaping structural and functional developmental abnormalities, but also affects the function of synapses in adulthood, contributes to accelerating aging of the brain, and changes the structural and functional background for development of AD and PD pathology. We hypothesize that we will be able to identify DS-specific modifications of the course of AD and PD pathology. This study will provide a foundation for identifying the mechanisms and morphological substrate of specific functional deficits, and should contribute to the improvement of diagnosis and treatment.