| Part 1 The Impact of Cerebral Microenviroment on Mi R-107Alzheimer’s disease(AD) is a neurodegenerative disease and the most common form of dementia among the elderly. After heart disease, cancer and stroke, Alzheimer’s disease has become the fourth largest cause of death on elderly. Although the pathogenesis of AD is not very clear, it’s accepted that Aβ aggregation deposition plays a key role in the pathogenesis of AD. Aβ is derived from the amyloid precursor protein catalysed by the β-secretase(BACE1) and γ-secretase. BACE1 is the rate-limiting enzyme in this biological processes. Micro RNA(~22nt) are non-coding single strand RNA molecules, and is a member of genes regulating family found in the evolution of plants and animals. In our clinical study, we find that mi R-107 in the MCI and AD patients was significantly lower than normal control. In addition, there have been reported that BACE1 is a target gene of mi R-107. Prompting us that mi R-107 reduction in patients is closely related to BACE1 increase and Aβ generation.It is noteworthy that, age is the most direct sick standards of Alzheimer’s disease, and the ability of the elderly to regulate the change of brain microenvironment is decline. We simulate the pathological conditions of microenvironment at the cellular level, including the mild endoplasmic reticulum stress, mild oxidative stress, inflammatory environment, hypoxia, glucose deprivation. Using Western blot and found endoplasmic reticulum stress and inflammatory environment can significantly increase the expression of BACE1 protein. Using real-time quantitative PCR, the m RNA level get consistent results with protein levels. We want to know whether mi R-107 will play a role in this process. We so detect the expression levels of mi R-107, and find mi R-107 have not changed in the endoplasmic reticulum stress and mild inflammatory environment. In the endoplasmic reticulum stress, cell is transfected with mi R-107 mimics and inhibitor, and confirmed mi R-107 don’t play a regulatory role in the process raised the BACE1. These results suggest that changes in the brain microenvironment can influence the expression of BACE1, but themechanism may be unrelated to the expression of mi R-107.Part 2 The Effects of HX24 on Promoting Neurite OutgrowthNerve growth factor(NGF) is a kind of polypeptide molecules, which exerts neurotrophic effects on nerve cells and plays an important role in the growth and development of neuron, neurotransmitter synthesis, cell apoptosis and axon growth. NGF relates to the development of many disease, including Alzheimer’s disease. Whether it changes the level itself or its receptor levels or functional changes have a significant impact on the pathophysiology of these diseases. A number of studies have indicated that, NGF has potential role in the treatment of Alzheimer’s disease. But as a preparation, poor pharmacokinetic properties, larger molecular weight, short half-life, unstable, difficult to cross the blood brain barrier and a higher price make it difficult for large-scale clinical application. Therefore, finding a small molecule which have a similar activity, high pharmacokinetic properties and less side effects is an effective way to solve this problem. In order to find a small molecule promoting the differentiation of neuron, we use PC12(rat pheochromocytoma cells) as a model, based on cell morphology, to take 12 small molecule compounds for activity screening. Selecting the HX24 as the research object, study its mechanism of promoting the neurite outgrowth. HX24 is initially determined that the pathway of MEK-ERK1/2-CREB is critical to promote neurite outgrowth in PC12 cells, and providing some basis for HX24 as a nerve growth factor analogue drug candidates. |
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