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標題: | 修飾細菌胞壁酰二肽對NOD2活性之影響 Modifications of bacterial cell wall Muramyl Dipeptides toward NOD2 stimulation study |
作者: | ZHEN-ZHUO TEO 張振卓 |
指導教授: | 梁碧惠(Pi-Hui Liang) |
關鍵字: | ?聚醣,細菌細胞壁,細菌胞壁二?,核?酸結合及寡聚化結構域樣受體 2, NOD2,muramyl dipeptide (MDP),peptidoglycan,immunology,innate immunity,peptides, |
出版年 : | 2018 |
學位: | 碩士 |
摘要: | 細菌細胞壁的主要成分為肽聚糖, 其中肽聚糖則是由重複性的N-乙酰-葡萄糖胺以及N-乙酰-胞壁酰基酸所構成。肽聚糖中的胞壁酰基二肽 (MDP) 被發現是核苷酸結合及寡聚化結構域樣受體2 (NOD2) 的最小促進單位。MDP被發現能夠結合到NOD2上促使NOD2活化進而釋放NF-B最終導致免疫反應的發生。目前為止,科學家針對MDP的衍生物做了不少的衍生以及探討,但是其中一些分子對於NOD2的研究並沒有述說的很詳細,因此本篇論文將透過針對這些位向 (糖端,胜肽端和C4端) 進行修飾並討論這些MDP的衍生物對於NOD2活性的影響。
首先,我們啟發自之前文獻的報導,利用三胜肽 [NH2-Gly-Ala-Glu(diOEt)] 與不同的雜環進行結合以取代MDP上的糖端。在這一部分,我們總共合成了19個分子。透過NOD2活化試驗的結果,我們發現化合物55G (萘官能基取代) 有不錯的NOD2觸發活性。有趣的是化合物55F (喹啉官能基取代) 雖然結構與55G非常相似,但是活性卻比55G弱了很多。 在第二部分,我們利用實驗室之前的方法來合成勝肽修飾的衍生物。透過這個方法,我們得到了11個MDP的衍生物。細胞試驗顯示MDP上的異谷氨酸在NOD2的活化上扮演著非常重要的角色。在這些分子中化合物64D(異谷氨酸上的羧基酰亜酸取代成乙酯)被發現為其中最有活性的分子(在10 nM, 2倍於MDP的活性)。 最後, 我們針對MDP的C4部分進行修飾,利用click reaction來產生C4三唑 (triazole) 取代的衍生物。透過這個方法,我們得到了5個分子。另一方面,我們也將C1的羥基修飾成C1-卞酯 (OBn) 從而探討C1-OBn以及C4位向的影響。透過試驗,我們發現C1-OBn以及C4-三唑取代都會造成NOD2的活性下降。 透過我的努力,一共有37個最終分子被合成出來。透過這些分子我們能夠更加的了解NOD2以及MDP之間的關係。對於提高異谷氨酸上的羧基酰亞胺部位的親脂性能夠很好的提高NOD2的活性,但目前並沒有找到最好的官能基,因此針對這部分的修飾將會在未來繼續進行。 Peptidoglycans (PGNs) are the major components of bacterial cell walls. They comprise of a repeating disaccharide unit commonly known as N-acetyl glucosamine-N-acetyl-muramic acid. Muramyl dipeptide (MDP) is the minimal structure of bacteria’s peptidoglycan for the NOD2 activation. MDP has been demonstrated to directly bind to NOD2, which stimulated NF-B production, and triggered innate immune responses. So far, strategies for MDP analogues are mainly for its adjuvanticity, NOD2 activity or anti-infectious activity. However, there are still some potions of MDP hadn’t been fully studied, for example the contribution of functional groups extending from C4 position. Therefore, the study of saccharide, peptide and C4-position of MDP are addressed in this thesis. Firstly, inspired from previous literature report, we applied the tripeptides [NH2-Gly-Ala-Glu(diOEt)] to couple with different heterocyclic, instead of sugar. Total 19 compounds were generated. From the NOD2 activation assay result, compound 55G, substituted by a naphthalene moiety, was found to be a potent NOD2 stimulator. Interestingly, compound 55F substituted by a quinoline moiety showed weak activity of NOD2 activation. Secondly, we modified on the peptide moiety of MDP using previous synthesis strategy developed by us. Total 11 MDP analogues were synthesized. The NOD2 assay showed that isoglutamine moiety was essential to NOD2 activation. Compound 64D, an amine moiety on isoglutamine replaced by ethoxyl moiety, was determined to be the most potent NOD2 stimulator so far (2-fold compared with MDP, 10 nM). Finally, we substituted the C4-position of MDP by triazole derivatives, sequentially coupled with azido-containing 50 yielded 5 compounds. At the same time, we also replaced the C1-OH into C1-OBn to study the C1 and C4 effect. From the NOD2 activation assay, we found both C1-OBn and C4-triazole substitution decreased the NOD2 activity. Through our effort, total 37 numbers of final compounds were generated. Based on the result, we can now have better understandings of the relationship between NOD2 and MDP more clearly. We found that modification on the peptide moiety can improve NOD2 activity. Future study on this position is needed. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/78874 |
DOI: | 10.6342/NTU201804311 |
全文授權: | 有償授權 |
電子全文公開日期: | 2024-03-11 |
顯示於系所單位: | 藥學系 |
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