Institute of Cellular Biology and Neurobiology, National Council of Research of Rome, Rome, Italy.
J Alzheimers Dis. 2013;33(1):265-72. doi: 10.3233/JAD-2012-112108.
Amyloid-β protein precursor (AβPP) is a ubiquitous protein found in all cell types, suggesting basic and yet important roles, which still remain to be fully elucidated. Loss of function of AβPP has been linked to abnormal neuronal morphology and synaptic function within the hippocampus and alterations in spatial learning, suggesting a neurotrophic role for this protein. Besides AβPP, nerve growth factor (NGF) and other neurotrophins have also been shown to finely modulate neuronal excitability, synaptic plasticity, and cognitive functions. In addition, recent data support the hypothesis of a functional interconnection between AβPP and NGF pathway. Here, we demonstrated that loss of AβPP function, leading to progressive decrease of choline acetyltransferase expression in the septum, correlates with age-related impairment of long-term potentiation (LTP) in the dentate gyrus. We next addressed whether impaired hippocampal plasticity in AβPP-null mice can be restored upon NGF treatment. Notably, NGF, as well as Pro-NGF, can fully revert LTP deficits in AβPP-null mice through p75NTR and JNK pathway activation. Overall the present study may unveil a new mechanism by which, in the absence of AβPP, NGF treatment may preferentially direct p75-neurotrophin-dependent JNK activation toward regeneration and plasticity in functionally relevant brain circuits.
淀粉样β蛋白前体(AβPP)是一种存在于所有细胞类型中的普遍蛋白,提示其具有基本但重要的作用,但仍有待充分阐明。AβPP 功能丧失与海马体中神经元形态和突触功能异常以及空间学习改变有关,提示该蛋白具有神经营养作用。除了 AβPP,神经生长因子(NGF)和其他神经营养因子也被证明可以精细调节神经元兴奋性、突触可塑性和认知功能。此外,最近的数据支持 AβPP 和 NGF 途径之间存在功能连接的假设。在这里,我们证明了 AβPP 功能丧失导致隔区胆碱乙酰转移酶表达逐渐下降,与年龄相关的齿状回长时程增强(LTP)损伤相关。接下来,我们研究了 AβPP 敲除小鼠海马可塑性损伤是否可以通过 NGF 治疗得到恢复。值得注意的是,NGF 以及 Pro-NGF 通过 p75NTR 和 JNK 途径的激活可以完全逆转 AβPP 敲除小鼠的 LTP 缺陷。总的来说,本研究可能揭示了一种新的机制,即在缺乏 AβPP 的情况下,NGF 治疗可能通过 p75-神经营养因子依赖性 JNK 激活优先促进功能相关脑回路的再生和可塑性。