請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/74711
標題: | Slc13a5基因剔除模擬飲食節制誘發增強小鼠記憶表現 Slc13a5 deletion mimics dietary restriction- enhanced memory performance |
作者: | Chih-Wei Sung 宋智暐 |
指導教授: | 王培育(Pei-Yu Wang) |
關鍵字: | 飲食節制,記憶,檸檬酸轉運體, Dietary restriction,memory,solute carrier family 13 member 5, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | Indy (I'm not dead yet) 最早在果蠅(Drosophila melanogaster)的研究上發現和壽命調控有關,故得其名。過去的文獻認為Indy以及其同源基因mIndy (mammalian Indy)表現降低對於生物體生理上的影響在許多方面和飲食節制(dietary restriction)相似。
在此,我們以mIndy基因全身性或組織專一性剔除小鼠進行實驗。mIndy又名solute carrier family 13 member 5 (Slc13a5)。根據資料庫顯示廣泛存在於許多器官,尤其在肝、腦表現量相對高,是一種檸檬酸鹽的運輸蛋白。實驗中使用的Slc13a5全身性剔除小鼠是在標的基因中插入一段序列干擾這段基因的轉錄,而這段序列中包含了一段LacZ基因,可以產生β-galactosidase,是常見的報告基因;因此,我們藉由X-gal染色發現Slc13a5表現在大腦中的嗅球、海馬迴、大腦皮質、視丘、中腦、小腦;為了解SLC13A5蛋白對於小鼠行為的影響,我們依據染色結果去進行記憶、嗅覺、肢體協調相關的實驗。發現當剔除Slc13a5,小鼠在記憶行為上表現較為優異。 為釐清Slc13a5基因缺失是如何產生這樣的結果,首先要確認的是哪個器官主導,因此以條件式基因剔除肝、神經Slc13a5的小鼠來驗證,我們發現是神經性的SLC13A5缺乏時會產生和全身性剔除時相似的結果。 串聯先前研究Slc13a5剔除和飲食節制相似的關係,我們試圖探討SLC13A5表現降低所帶來的影響是否和飲食節制有部分的重疊。結果顯示當Slc13a5基因全身性剔除小鼠進行飲食節制後並不會進一步提升記憶方面的表現。 承接記憶力改善的現象,我們去檢測海馬迴中腦源性神經滋養因子的RNA表現,發現Slc13a5全身性剔除以及神經專一性剔除小鼠有較高的表現,顯示腦部微環境有利於神經新生與發育。我們進一步利用免疫螢光染色審視神經新生的狀況時,發現Slc13a5全身性剔除和神經專一性剔除小鼠海馬迴(hippocampus)中的齒狀回(dentate gyrus)呈現較多doublecortin(未成熟神經細胞標記)和Ki67(細胞生長分裂標記)陽性的細胞,代表有較高的神經新生以及神經可塑性,對於學習與記憶的有正向相關性,可用於解釋記憶力改善的現象。 Solute carrier family 13 member 5 (Slc13a5) is the mammalian homolog of Drosophila melanogaster INDY (I’m Not Dead Yet) gene, and it has been found to mimic dietary restriction (DR) in many aspects under the loss of function conditions, including restrained overall growth and altered metabolism. Previous studies suggest that Slc13a5 is mainly expressed in liver, brain, salivary gland and testis. Furthermore, it is known that Slc13a5 is expressed in different regions of the brain including the olfactory bulb, hippocampus, cerebral cortex, thalamus, midbrain, and cerebellum. Therefore, we hypothesized Slc13a5 could be involved in olfactory, motor and memory functions. We performed various behavior tests to evaluate thereafter. We observed DR and loss of Slc13a5 did not influence either anxiety, depression or locomotor activity. Moreover, food manipulation had an effect on olfaction and motor coordination in control and Slc13a5-/- mice. Interestingly, we found that mice performed better in the memory tasks under DR or Slc13a5 gene knockout. We used liver- and neuron-specific Slc13a5 knockout mice to further investigate its role. We observed that neuron-specific knockout mice had a better cognitive performance. Whereas loss of Slc13a5 in the liver did not show any difference in cognitive performance compared to control. To figure out the possible mechanisms behind improved memory caused by Slc13a5 deletion, we checked the brain-derived neurotrophic factor (Bdnf) gene expression levels in the hippocampus. We observed elevated Bdnf levels which revealed that loss of Slc13a5 provides a suitable microenvironment for neurogenesis. We performed doublecortin (DCX, a marker of immature neurons) and Ki67 (a marker of proliferating cells) immunostaining to further confirm our hypothesis. We observed increased DCX positive and Ki67 positive cells in the dentate gyrus of mice under neuron-specific Slc13a5 gene knockout and DR. In conclusion, we suggested that neuron-specific Slc13a5 gene knockout and DR can enhance memory performance through upregulating the activity of neurogenesis. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/74711 |
DOI: | 10.6342/NTU201901577 |
全文授權: | 有償授權 |
顯示於系所單位: | 腦與心智科學研究所 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-108-1.pdf 目前未授權公開取用 | 3.48 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。