本文選題：黏菌素 + 凋亡��； 參考：《中國農(nóng)業(yè)大學》2017年博士論文

【摘要】：多黏菌素(包括多黏菌素B及黏菌素)是臨床治療多重耐藥革蘭氏陰性細菌感染的最為重要抗生素之一。多黏菌素腎毒性及神經(jīng)毒性是其臨床使用過程中主要毒副作用及劑量限制性因素,但其分子毒性機制尚不清楚。本文通過建立小鼠及體外細胞模型系統(tǒng)研究了黏菌素誘導(dǎo)細胞凋亡及自噬的分子機制,并進一步探究了靶向調(diào)控細胞凋亡及自噬信號通路對黏菌素腎毒性及神經(jīng)毒性的影響。主要發(fā)現(xiàn)如下:(1)使用小鼠及體外細胞模型(HEK293及N2a細胞系)研究證實,黏菌素可通過劑量依賴性誘導(dǎo)氧化應(yīng)激介導(dǎo)的線粒體功能失調(diào),激活線粒體、死亡受體及內(nèi)質(zhì)網(wǎng)凋亡通路;同時激活NF-κB、MAPKs、p53、Nrf2/ARE、Akt等信號通路。其中,ERK、JNK信號通路的激活在黏菌素誘導(dǎo)的細胞凋亡中發(fā)揮保護性作用,P53的激活及Akt信號通路的抑制發(fā)揮促凋亡的作用。(2)黏菌素暴露可上調(diào)組織及細胞內(nèi)Beclin1表達及LC3Ⅱ/Ⅰ比率,伴隨明顯的自噬-溶酶體及自噬體結(jié)構(gòu),表明黏菌素處理激活細胞自噬,通過使用GFP-LC3質(zhì)粒轉(zhuǎn)染后進一步證實。進一步使用N2a細胞模型研究證實,自噬抑制劑氯喹(CQ)依賴于ROS介導(dǎo)的氧化應(yīng)激損傷及casapse激活,加劇黏菌素誘導(dǎo)的細胞凋亡。雷帕霉素,可特異性的抑制mTOR/p70s6k信號通路,上調(diào)Akt/CREB、Nrf2/ARE等信號通路信號通路及ULK1依賴性的細胞自噬及其降解過程,改善黏菌素誘導(dǎo)的氧化應(yīng)激損傷、線粒體功能失調(diào)及caspase激活介導(dǎo)的細胞凋亡;小鼠原代神經(jīng)元及動物模型進一步驗證了自噬的保護性作用。(3)姜黃素及黃芩素補充能夠提高動物體內(nèi)及細胞抗氧化、抗炎能力,上調(diào)Nrf2/HO-1信號通路及ULK1介導(dǎo)的細胞自噬,下調(diào)黏菌素受體蛋白Megalin表達、p53蛋白表達,顯著改善黏菌素對組織/細胞造成的的氧化應(yīng)激損傷、caspase依賴性凋亡及NF-κB信號通路介導(dǎo)的炎癥反應(yīng),從而改善黏菌素誘導(dǎo)的神經(jīng)毒性及腎毒性。(4)體外及動物模型研究發(fā)現(xiàn),抗生素藥物米諾環(huán)素能夠通過清除細胞內(nèi)ROS,抑制氧化應(yīng)激、caspase激活及細胞凋亡,有效降低黏菌素誘導(dǎo)的神經(jīng)毒性及腎毒性,具有重要的臨床應(yīng)用價值。綜上所述,黏菌素誘導(dǎo)的神經(jīng)毒性及腎毒性涉及外源性及內(nèi)源性細胞凋亡通、ULK1介導(dǎo)的細胞自噬及NF-κB介導(dǎo)的炎癥反應(yīng)。藥理性激活A(yù)kt/CREB、Nrf2/HO-1及自噬可通過抑制氧化損傷及細胞凋亡能夠有效降低黏菌素腎毒性及神經(jīng)毒性。本研究為新一代多黏菌素脂肽類抗生素的開發(fā)、多黏菌素聯(lián)合用藥、減毒策略提供了重要的理論參考依據(jù)。
[Abstract]:Polymyxin (including polymyxin B and myxin) is one of the most important antibiotics for the treatment of multidrug resistant gram-negative bacterial infections. The nephrotoxicity and neurotoxicity of polymyxin are the main side effects and dose limiting factors in clinical use, but the molecular toxicity mechanism is not clear. The molecular mechanism of myxin induced apoptosis and autophagy was studied by establishing mouse and in vitro cell models, and the effects of targeted regulation of apoptosis and autophagy signaling pathway on myxin nephrotoxicity and neurotoxicity were further explored. The main findings were as follows: (1) using mouse and in vitro cell models (HEK293 and N2a cell lines), it was demonstrated that myxin could induce mitochondrial dysfunction mediated by oxidative stress in a dose-dependent manner and activate mitochondria, death receptors and endoplasmic reticulum (ER) apoptosis pathway. At the same time, the signal pathway of NF- 魏 B mapksmapk p53 Nrf 2 / AREN Akt was activated. The activation of JNK signaling pathway in ERK plays a protective role in myxin-induced apoptosis. The activation of p53 and the inhibition of Akt signaling pathway play a role in promoting apoptosis.) Myxin exposure can up-regulate the expression of Beclin1 and the ratio of LC3 鈪，

本文編號：1955387