TRAIL诱导U937细胞凋亡和自噬的分子机制研究

发布时间：2018-04-30 04:33

本文选题：肿瘤坏死因子相关凋亡诱导配体 + 凋亡　；参考：《北京协和医学院》2011年博士论文

【摘要】：细胞凋亡是机体免疫调节的重要方式,是机体维持免疫系统稳定,避免自身免疫性疾病发生的重要机制。单核/巨噬细胞是一类重要的免疫细胞,同时具有效应细胞和抗原递呈细胞的功能。了解单核/巨噬细胞复杂的生存和凋亡的分子调控网络,协调细胞的命运,实现单核/巨噬细胞基本生物学功能,对肿瘤、炎症和自身免疫等疾病的研究和干预都有着极为重要的指导作用。 TRAIL(tumor necrosis factor (TNF)-related apoptosis-inducing ligand)是肿瘤坏死因子(TNF)超家族的成员,可特异性地诱导肿瘤细胞凋亡,而对大多数的正常细胞没有毒副作用,显示TRAIL在肿瘤治疗方面具有广阔的应用前景。除此以外,TRAIL还参与炎症、感染和自身免疫性疾病的调节。本论文首次发现TRAIL不仅能够诱导caspase依赖的单核/巨噬细胞凋亡,而且可以引起自噬。在TRAIL诱导单核/巨噬细胞凋亡过程中,加入自噬特异性抑制剂3-MA可以显著激活caspase-3、-8和-9,使细胞凋亡率上升40-60%；而且,细胞内LC3(microtubule-associated protein1A/1B-light chain3)表达显著增强,RIP1表达逐渐上调,IKK复合体聚集,NF-κB活性增强,细胞自噬水平呈先增强的趋势；随着TRAIL和3-MA刺激时间的延长,RIP1发生去泛素化,与NEMO形成的线性泛素链解体,致使细胞由自噬向凋亡转变,DISC复合物内caspase-8和c-FLIP切割形式发生转变,随着caspase-8的p41/43和c-FLIP的p22相应剪切体的形成,caspase-8活性明显增强；随后,RIP1进一步降解,其蛋白量减少,NF-κB活性受到抑制,从而促进细胞凋亡增加。提示在TRAIL诱导单核/巨噬细胞凋亡的初期,自噬对细胞的存活起保护作用,RIP1泛素化修饰状态改变成为细胞凋亡新的起始点,调节细胞凋亡。综上所述,TRAIL诱导单核／巨噬细胞凋亡过程中,自噬起重要保护作用,TRAIL通过调节RIP1表达及其泛素化修饰调节自噬到凋亡的转变,凋亡与自噬的调节决定细胞的命运。本论文首次发现TRAIL不仅能够诱导单核／巨噬细胞凋亡,而且可以引起自噬。RIP1是调节TRAIL诱导单核/巨噬细胞凋亡和自噬的关键分子。这一研究结果对于更加深入地理解细胞凋亡和自噬调节的分子机制、以及TRAIL用于肿瘤、炎症和自身免疫等疾病的研究和治疗都具有重要指导意义。
[Abstract]:Apoptosis is an important way of immune regulation and an important mechanism to maintain the stability of immune system and avoid autoimmune diseases. Mononuclear / macrophages are important immune cells with the functions of effector cells and antigen presenting cells. Understand the complex molecular regulatory network of mononuclear / macrophage survival and apoptosis, coordinate the fate of cells, realize the basic biological functions of mononuclear / macrophage, The research and intervention of diseases such as inflammation and autoimmune play an important role in guiding. TRAIL(tumor necrosis factor TNF-related apoptosis-inducing ligand is a member of the tumor necrosis factor-related apoptosis-inducing (TNF-related) superfamily, which can specifically induce apoptosis of tumor cells, but has no side effects on most normal cells, indicating that TRAIL has a broad application prospect in tumor therapy. In addition, trail is involved in the regulation of inflammation, infection and autoimmune diseases. In this paper, we first found that TRAIL can not only induce caspase dependent mononuclear / macrophage apoptosis, but also induce autophagy. In the process of mononuclear / macrophage apoptosis induced by TRAIL, the addition of autophagy specific inhibitor 3-MA could significantly activate caspase-3, caspase-3, caspase-3, and increase the apoptosis rate by 40 to 60 percent. The expression of LC3(microtubule-associated protein1A/1B-light chain3) increased significantly, the expression of RIP1 increased gradually, the activity of NF- 魏 B increased and the level of autophagy increased first, and with the prolongation of TRAIL and 3-MA stimulation time, the expression of RIP1 became diubiquitin, and the activity of NF- 魏 B increased gradually, and the level of autophagy increased at first. The dissolution of the linear ubiquitin chain formed with NEMO resulted in the transformation of caspase-8 and c-FLIP cleavage from autophagy to apoptosis, which increased with the formation of corresponding shearing bodies of p41 / 43 of caspase-8 and p22 of c-FLIP, and further degradation of RIP1. The activity of NF- 魏 B was inhibited by the decrease of its protein content, which promoted the increase of apoptosis. These results suggest that autophagy may protect the survival of mononuclear / macrophage cells from apoptosis induced by TRAIL. The alteration of RIP1 Ubiquification modification may become a new starting point for apoptosis and regulate apoptosis. In the process of trail inducing monocyte / macrophage apoptosis, autophagy plays an important protective role. Trail regulates the transition from autophagy to apoptosis by regulating RIP1 expression and Ubiquitin modification. Apoptosis and autophagy regulate the fate of cells. In this paper, we first found that TRAIL can not only induce monocyte / macrophage apoptosis, but also induce autophagy. RIP1 is the key molecule to regulate monocyte / macrophage apoptosis and autophagy induced by TRAIL. These results are of great significance for further understanding the molecular mechanisms of apoptosis and autophagy, and for the application of TRAIL in the study and treatment of tumor, inflammation and autoimmune diseases.
【学位授予单位】：北京协和医学院
【学位级别】：博士
【学位授予年份】：2011
【分类号】：R363

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