Establishment of curative therapy for Alzheimer's disease with Humanin peptides

本研究期间，我们发现并报道了Humanin（HN）对阿尔茨海默病（AD）相关神经元的保护作用机制，以及AD相关神经元死亡的新机制，特别是发现了淀粉样前体蛋白（APP）的天然和神经元细胞死亡诱导配体。并抑制AD相关损伤（如家族性AD（FAD）相关APP突变体、早老素-1（PS1）突变体、PS2突变体、神经毒性淀粉样蛋白-β肽）引起的神经元细胞死亡。HN的神经保护功能尚不完全清楚。我们成功地HN-衍生物，其没有神经保护活性，但具有其自身二聚化活性。迄今为止，典型的酪氨酸激酶抑制剂genetistein抑制了HN对V642 I-APP诱导的F11神经杂交细胞死亡的抑制作用。因此，我们使用vario ...更多信息 US激酶抑制剂和突变基因，其可作为显性负性形式。我们确定了信号转导和转录3（STAT 3）参与HN对AD相关损伤诱导的神经元细胞死亡的神经保护活性。这表明HN的假定受体复合物位于STAT 3的上游，并与某些酪氨酸激酶相关。这些结果对HN受体复合物的鉴定以及类似HN作用的小分子化合物的鉴定具有重要意义。2. AD相关神经细胞死亡的分子机制目前，我们发现并报道了针对APP胞外区的单克隆抗体22 C11能够诱导神经细胞死亡。此外，我们还报道了百日咳毒素（PTX）敏感的Go蛋白、Gβγ蛋白、c-Jun N-末端激酶、NADPH氧化酶和caspase-3/相关caspase参与神经细胞死亡。通过各种结合实验和细胞死亡实验，我们发现转化生长因子β2（transforming growth factor β2，TGFβ2）与APP的胞外区结合，以PTX敏感的方式通过APP诱导神经细胞死亡。此外，我们还观察了TGFβ2在18月龄雌性Tg 2576阿尔茨海默病模型小鼠大脑皮层M1区的蛋白表达。提示TGF β_2可能参与AD的发病过程。p75神经营养因子受体（p75 NTR）是Aβ受体的候选者，可引起神经元细胞死亡。2002年，Frankowski等鉴定了PLAIDD分子，与p75 NTR相似。因此，我们试图研究PLAIDD在Aβ/p75 NTR诱导的神经元细胞死亡中的参与。结果表明，PTX敏感的Gi蛋白与PLAIDD的胞内结构域结合，Aβ/p75 NTR/PLAIDD与Aβ/p75 NTR一样，可引起神经细胞死亡。少

In this research term, we found and reported that the mechanism of Humanin (HN) neuroprotective activity against Alzheimer's disease (AD)-relevant indults and the novel AD-relevant neuronal cell death mechanisms, especially we found the natural and neuronal cell death inducible ligand for amyloid precursor protein (APP).1.The mechanisms of HN neuroprotectionIn 2001, we found HN which is consisted of 24 amino acids, and inhibited neuronal cell death by AD-relevant insults such as familial AD (FAD)-linked APP mutants, presenilin-1 (PS1) mutants, PS2 mutants, neurotoxic amyloid-β peptides. It is not fully understood the HN neuroprotective functions. We succeeded HN-derivatives which have no neuroprotective activity but have its self-dimerization activity. So, these derivatives (P3A, L12A, S14A, and P19A) can act as HN antagonists.Until now, genetistein, a typical tyrosine kinase inhibitor, inhibited HN activity against V642I-APP-induced F11 neurohybrid cell death. Therefore, we used vario … More us kinase inhibitors and mutant genes which can act as dominant negative forms. We identified the involvement of signal transducer and transcription 3 (STAT3) in HN neuroprotective activity against AD-relevant insults induced neuronal cell death. These indicated that the putative receptor complex for HN is upstreams of STAT3 and related to certain tyrosine kinases. These results are important for the identification of HN receptor complex and small compound which can mimic HN action.2.The molecular mechanisms of AD-relevant neuronal cell deathUntil now, we found and reported that 22C11, a monoclonal antibody developed against extracellular domain of APP, can induce neuronal cell death. In addition, we reported that pertussis toxin (PTX) sensitive Go protein, Gβγ proteins, c-Jun N-terminal kinase, NADPH oxidase, and caspase-3/related caspase are involved in the neuronal cell death. By various binding experiments and cell death experiments, we found that transforming growth factor β2 (TGFβ2) binds to the extracellular domain of APP and induce the neuronal cell death via APP in PTX sensitive manner. In addition, we reported that the protein expression of TGFβ2 in cortex M1 region of 18-months-old female Tg2576 Alzheimer's disease model mouse. From these results, there is a possibility that TGFb2 is involved in the onset of AD.The p75 neurotrophin receptor (p75NTR) is a candidate for Aβ receptor which can cause neuronal cell death. In 2002, PLAIDD molecule has been identified by Frankowski et al., and is similar to p75NTR. Therefore, we attempted to investigated the involvement of PLAIDD in Aβ/p75NTR-induced neuronal cell death. From the results, we concluded that PTX sensitive Gi proteins bind to the intracellular domain of PLAIDD and Aβ/p75NTR/PLAIDD can trigger the neuronal cell death as same as Aβ/p75NTR. Less