中草藥中減緩Aβ誘導不正常神經病理純物質之篩選及其作用機轉之探討

To search and investigate the pure compound purified from herbal extracts by which it alleviates Aβ-induced neuronal pathophysiology.

林恬瑄(Lin Tian-Syuan)

指導教授 ： 林炎壽

國立臺灣師範大學/理學院/生命科學系/碩士(2016年)

https://doi.org/10.6345/NTNU202205148

摘要

阿茲海默症(AD)是最常見的神經退化性疾病之一，導致記憶和其他認知上功能的障礙。目前的研究認為是β類澱粉蛋白斑塊(Aβ)的累積和神經元纖維的糾結，這兩個因素與突觸的損壞及神經死亡有關。又在阿茲海默症中Aβ會誘導不正常的麩胺酸神經傳遞，進而過度刺激突觸上的麩胺酸受體如AMPAR, NMDAR, Kainate receptor和mGluR1/ 3/5，最後導致細胞產生興奮性毒性而使神經元死亡。美金剛(Memantine)，為N-甲基-D-天冬氨酸(NMDA)受體拮抗劑，已被使用於治療中度至重度阿茲海默病人，更深化了這項觀點。我們研究旨在篩選能改善Aβ誘導病理性神經傳遞之中草藥。利用出生後1-3天小鼠腦中分離培養初級皮質神經元，以免疫螢光染色及西方點墨法觀察之後具有如vGLUT1/ 2, AMPAR, NMDAR, PSD95, type III tubulin等麩胺酸神經元和神經元連結的特殊標記。又將這些神經與一種對膜電位改變敏感稱之為DiBAC4(3)的藥劑處理，經過β類澱粉蛋白胺基酸1-42的寡聚形式刺激後，發現可以偵測到這些神經元去極化的現象。利用這個平台，我們在16種中草藥單方的萃取物中發現6種能有效地減緩Aβ誘導的異常去極化現象，暫時命名其中兩種中草藥為P1029和P1033。我們進一步在這單方中找到有效的純物質，暫時命名為P1033-BE，且找出其對初級培養神經細胞存活率的IC50濃度，再利用麩胺酸接受器的致效劑與抑制劑後，我們更發現P1033-BE可能透過NMDAR及AMPAR來降低Aβ所誘導的神經不正常去及化現象，目前P1033-BE對Aβ在分子機制上如訊息傳導路徑分子的機制研究正在進行中。此研究期望最終能使P1033-BE成為臨床上治療阿茲海默患者的藥物。

關鍵字

阿茲海默症 ； β類澱粉蛋白 ； 麩胺酸神經元 ； 神經傳導 ； 中草藥

並列摘要

Alzheimer’s disease (AD), one of the most common neurodegenerative diseases, leads to memory impairment and other cognitive problems. The two pathological hallmarks of AD are accumulation of β-amyloid (Aβ) plaques and neurofibrillary tangles, by which they associate with synapse loss and neuronal death. Recent studies have indicated that Aβ-induced glutamate neurotransmission may play a crucial role in AD. A rise in glutamate could result in over-stimulating synaptic glutamate receptors such as AMPAR, NMDAR, Kainate receptor, and mGluR1/3/5, and subsequently cause neuronal cell death. The clinical use of memantine, an uncompetitive N-methyl-D-aspartate (NMDA) antagonist, strengthens this opinion. In this study, we screened Chinese herbal medicines/herbal extracts for ameliorating the Aβ-induced pathophysiological neurotransmission. We established the primary culture of cortical neurons isolated from postnatal 1-3 days mice. These neurons have been characterized by markers of glutamatergic neurons and neuronal networks such as vGLUT1/2, AMPAR, NMDAR, PSD95, type III tubulin. After stimulating by oligomeric forms of Aβ 1-42, these neurons depolarize, indicating by a slow response voltage sensitive dye DiBAC4(3). Utilizing this platform, we found 6 out of 16 herbal extracts which are effective to alleviate Aβ-induced abnormal depolarization and temporarily named two of them P1029 and P1033. We also eventually found a pure compound, P1033-BE, is capable to block Aβ-induced abnormal depolarization. Using agonists and antagonists of glutamatergic receptors, we dissect that the effect of P1033-BE could mediate through NMDAR and AMPAR. The molecular mechanisms of this effective pure compound on which pathways are being explored. Hopefully, we will make this ultimately become clinical drugs to treat AD patients.

並列關鍵字

Alzheimer’s disease ； Amyloid β ； Glutamatergic neurons ； Synaptic transmission ； Chinese herbal medicines

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