本文選題：β-淀粉樣多肽 + α-突觸核蛋白��； 參考：《復(fù)旦大學(xué)》2013年博士論文

【摘要】：阿爾茲海默病和帕金森病嚴(yán)重威害人類健康。人們研究它們的發(fā)病機(jī)理發(fā)現(xiàn),它們分別與p淀粉樣(Aβ)多肽和a突觸核(AS)蛋白的錯(cuò)誤折疊和聚集密切相關(guān)。由于錯(cuò)誤折疊和聚集,這些蛋白從正常生理狀態(tài)下可溶性單體聚集成致病的可溶性的毒性聚集體和不可溶性淀粉樣纖維,伴隨著組織損傷和疾病的產(chǎn)生。因此,人們開(kāi)始嘗試從新的角度分析、研究和治療AD,例如尋找可抑制寡聚體生成的化合物,或?qū)⒁研纬傻睦w維解聚成無(wú)毒性的聚集體而非有毒性的纖維前體。然而,目前關(guān)于這類化合物的研究報(bào)導(dǎo)尚不充分,這些化合物的作用機(jī)理仍不清楚。 近年研究發(fā)現(xiàn),金屬離子能引發(fā)Ap多肽和AS蛋白構(gòu)象轉(zhuǎn)變,誘導(dǎo)它們形成毒性聚集體。我們?cè)O(shè)想：可尋找有效的金屬離子絡(luò)合劑,通過(guò)其對(duì)金屬離子的捕捉作用,抑制金屬離子與蛋白的相互作用,減少金屬離子誘導(dǎo)蛋白纖維化聚集和神經(jīng)毒性。 盡管對(duì)于神經(jīng)退性疾病的治療目前尚無(wú)臨床根治性藥物,但一些天然小分子化合物因潛在用于治療此類疾病而被重視。在這些天然小分子化合物中,姜黃素可以與金屬離子和神經(jīng)退行性疾病相關(guān)蛋白發(fā)生相互作用。然而,目前關(guān)于姜黃素與金屬離子共同干預(yù)下對(duì)Ap多肽和AS蛋白的纖維化和神經(jīng)毒性的影響報(bào)導(dǎo)甚少。此外,海藻糖因顯著抑制Ap多肽聚集引起了重點(diǎn)關(guān)注�；贏S蛋白與Ap多肽纖維化動(dòng)力學(xué)機(jī)理的相似性,我們推測(cè)海藻糖亦可能抑制AS蛋白的聚集而可能潛在地用于治療PD。 本文試圖通過(guò)研究姜黃素對(duì)金屬離子誘導(dǎo)的蛋白聚集和神經(jīng)毒性的干預(yù)作用以及海藻糖對(duì)AS蛋白聚集和神經(jīng)毒性的影響,探索這些小分子化合物在神經(jīng)退行性疾病中的預(yù)防與治療作用機(jī)理,為開(kāi)發(fā)它們?yōu)橹委熒窠?jīng)退行性疾病新藥提供理論基礎(chǔ)。本文的主要發(fā)現(xiàn)如下： (1)姜黃素對(duì)鋁(Ⅲ)離子和鐵(Ⅲ)離子誘導(dǎo)絲素蛋白構(gòu)象轉(zhuǎn)變的干預(yù)作用 基于絲素蛋白與神經(jīng)退行性疾病相關(guān)蛋白的相似性,我們采用絲素蛋白為模型蛋白,研究姜黃素對(duì)鐵離子和鋁離子誘導(dǎo)的蛋白構(gòu)象轉(zhuǎn)變的影響。研究發(fā)現(xiàn),鐵離子和鋁離子均能明顯促進(jìn)絲素蛋白構(gòu)象向p-折疊轉(zhuǎn)變；姜黃素因?qū)饘匐x子具有強(qiáng)絡(luò)合能力,而抑制金屬離子誘導(dǎo)絲素蛋白構(gòu)象向p-折疊轉(zhuǎn)變的作用。有意義的是,本章研究進(jìn)一步發(fā)現(xiàn),當(dāng)[Al(Ⅲ)]/[curcumin]混合比介于1：1至1：2時(shí),形成的Al(Ⅲ)-curcumin絡(luò)合物,不僅可以有效抑制絲素蛋白β-折疊的形成,而且可將已形成的ê-折疊構(gòu)象解折疊成無(wú)規(guī)卷曲構(gòu)象。 (2)姜黃素對(duì)鋁(Ⅲ)離子誘導(dǎo)Aβ42多肽聚集及神經(jīng)毒性的抑制作用 鋁(Ⅲ)能明顯促進(jìn)Aβ42多肽纖維化,增加Aβ42多肽的神經(jīng)毒性,而姜黃素能抑制此過(guò)程。此外,姜黃素因?qū)饘匐x子具有強(qiáng)絡(luò)合能力,不僅可抑制金屬離子誘導(dǎo)Aβ42纖維化作用,而且形成的鋁(Ⅲ)—姜黃素絡(luò)合物可將已形成的Aβ42纖維解聚集成低毒性的無(wú)定形聚集體。 (3)海藻糖對(duì)野生型和A53T突變型α-突觸核蛋白纖維化聚集的干預(yù)作用 海藻糖與野生型AS蛋白共孵育時(shí),在孵育前期,海藻糖誘導(dǎo)形成較大的野生型AS無(wú)定形聚集體,在孵育后期,這些預(yù)形成的較大無(wú)定形聚集體被解聚成小的非折疊態(tài)的無(wú)定形聚集體甚至單體。此外,當(dāng)存在低濃度海藻糖干預(yù)時(shí),海藻糖雖不能有效抑制A53T突變型AS原纖維的形成,但在孵育后期可將已形成的A53T突變型AS原纖維解聚集成可溶性的非折疊態(tài)聚集體甚至單體。當(dāng)存在高濃度海藻糖干預(yù)時(shí),海藻糖通過(guò)穩(wěn)定A53T-AS寡聚體和原絲結(jié)構(gòu),顯著抑制A53T-AS纖維的形成。 (4)海藻糖和姜黃素干預(yù)野生型和A53T突變型α-突觸核蛋白在轉(zhuǎn)基因PC12細(xì)胞模型中的過(guò)表達(dá)和細(xì)胞毒性 濃度低于1mM的海藻糖以及姜黃素與鋁以1：1混合時(shí)生成的絡(luò)合物,能明顯抑制野生型AS和A53T突變型AS蛋白在轉(zhuǎn)基因PC12細(xì)胞內(nèi)的過(guò)表達(dá),且能抑制野生型AS和A53T突變型AS在細(xì)胞內(nèi)的毒性,提高細(xì)胞活力。此外,姜黃素與鋁以1：1混合時(shí),生成的絡(luò)合物,能明顯抑制雙氧水和鋁離子誘導(dǎo)的AS過(guò)表達(dá)和神經(jīng)毒性。 本文研究表明,鋁(Ⅲ)—姜黃素絡(luò)合物和海藻糖可能是潛在的神經(jīng)退行疾病治療藥物,值得進(jìn)一步研究和證實(shí)。
[Abstract]:Alzheimer's and Parkinson's disease seriously harm human health. The study of their pathogenesis has found that they are closely related to the misfolding and aggregation of the P amyloid (A beta) polypeptide and the a synaptic nucleus (AS) protein. Sexual toxic aggregates and insoluble amyloid fibers are accompanied by tissue damage and disease. Therefore, people have begun to attempt to analyze and treat AD from a new perspective, such as finding compounds that can inhibit oligomers, or depolymerize the formed fibers into nontoxic aggregates rather than toxic fibrous precursors. At present, the research reports on these compounds are not enough, and the mechanism of these compounds is still unclear.
Recent studies have found that metal ions can induce the conformation transition of Ap peptides and AS proteins and induce them to form toxic aggregates. We assume that an effective metal ion complexing agent can be found to inhibit the interaction of metal ions with proteins by its capture of metal ions and reduce the aggregation of fibrin induced proteins and nerves in metal ions. Toxicity.
Although there are no clinical radical drugs for the treatment of neurodegenerative diseases, some natural small molecular compounds are valued for their potential for the treatment of such diseases. In these natural small molecular compounds, curcumin can interact with metal ions and neurodegenerative diseases related proteins. However, Jiang Huang is currently concerned. There are few reports on the effects of Ap polypeptide and AS protein on the fibrosis and neurotoxicity of the peptide and the metal ions. In addition, trehalose is a major concern for inhibiting the aggregation of Ap polypeptide. Based on the similarity of the kinetic mechanism of the AS protein to the Ap polypeptide fibrosis, we speculate that the alga may also inhibit the aggregation of AS protein and possibly submersible. In the field for the treatment of PD.
The effect of curcumin on protein aggregation and neurotoxicity induced by curcumin and the effect of trehalose on AS protein aggregation and neurotoxicity are explored to explore the mechanism of the prevention and treatment of these small molecular compounds in neurodegenerative diseases, in order to develop new drugs for the treatment of neurodegenerative diseases. The main findings of this paper are as follows:
(1) the intervention of curcumin on the conformation transition of silk fibroin induced by aluminum (III) ions and iron (III) ions.
Based on the similarity between silk fibroin and neurodegenerative diseases, we used fibroin as model protein to study the effect of curcumin on the conformation of protein conformation induced by iron and aluminum ions. It was found that both iron and aluminum ions could obviously promote the transformation of the conformation of silk fibroin to p-, and curcumin was isolated from metal. It is significant that the Al (III) -curcumin complex formed when the [Al (III)]/[curcumin] mixture ratio is between 1:1 and 1:2, can not only effectively inhibit the formation of the fibroin beta - folding, but also can be used to inhibit the formation of the p- (III) -curcumin complex. The formed folded conformation is folded into a random conformation.
(2) curcumin inhibits the aggregation and neurotoxicity of A (42) peptide induced by aluminum (III) ion.
Aluminum (III) can obviously promote the fibrosis of A beta 42 polypeptide, increase the neurotoxicity of A beta 42 polypeptide, and curcumin can inhibit this process. In addition, curcumin can inhibit metal ions induced A beta 42 fibrosis due to metal ions, and the formed aluminum (III) curcumin complex can depolymerization the formed A beta 42 fiber. Integrated low toxic amorphous aggregates.
(3) trehalose intervention on fibroblast aggregation of wild-type and A53T mutant alpha synuclein
In the incubation period of trehalose and wild type AS protein, trehalose induced the formation of large wild type AS amorphous aggregates at the pre incubation period. In the late incubation period, these pre formed large amorphous aggregates were depolymerize into small unfolded amorphous aggregates and even monomers. It can effectively inhibit the formation of the A53T mutant AS fibrils, but in the late incubation period, the formed A53T mutated AS fibrils can be disassembled into soluble non folded aggregates or even monomers. When there is high concentration trehalose intervention, trehalose significantly inhibits the formation of A53T-AS fibers by stabilizing the A53T-AS oligomer and precursor structure.
(4) trehalose and curcumin interfere the overexpression and cytotoxicity of wild-type and A53T mutant alpha synuclein in transgenic PC12 cell models.
The complex of trehalose with a concentration of less than 1mM and the complex of curcumin and aluminum when mixed with 1:1 can obviously inhibit the overexpression of wild type AS and A53T mutated AS protein in the transgenic PC12 cells, and can inhibit the toxicity of the wild type AS and A53T mutants AS in the cells and increase the viability of the cells. The complex can inhibit AS overexpression and neurotoxicity induced by hydrogen peroxide and aluminum ions.
This study indicates that aluminum (III) - Curcumin complex and trehalose may be potential drugs for the treatment of neurodegenerative diseases, and deserve further study and confirmation.

【學(xué)位授予單位】：復(fù)旦大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2013
【分類號(hào)】：R742;R749.16

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相關(guān)期刊論文 前2條

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本文編號(hào)：1785789