自噬在NK细胞抗肿瘤效应中作用及其机制研究

发布时间：2018-12-15 22:54

【摘要】：自噬(Autophagy)是真核细胞内发生的,依靠两个泛素样结合系统(Atg12和Atg8/LC3结合系统)形成的双层膜结构,将包裹的胞内成分传递到溶酶体进行降解,从而维持细胞结构成分稳态的代谢机制。NK细胞(Natural killer cells)是机体固有免疫系统中重要的一员,在机体抗肿瘤和抗感染免疫中起着不可缺少的作用。关于NK细胞自噬活性的改变对NK细胞杀伤功能的影响,目前国内外未见报道。因此,本课题利用自噬基因Atg3和Atg7条件性敲除小鼠对上述内容进行了探究。我们利用他莫昔芬先敲除Atg3f/f ER-cre小鼠的Atg3自噬基因和Atg7f/f UbiER-cre小鼠的Atg7自噬基因,发现敲除组小鼠的NK细胞体外杀伤能力明显增强,并且胞内具有更多的杀伤分子穿孔素和颗粒酶B。小鼠体内实验结果也显示,自噬缺陷的小鼠具有较强的抗肿瘤活性并且存活期延长。进一步机制研究发现,自噬缺陷NK细胞的分化成熟以及活化程度(IFN-y合成)并没有变化。同时自噬缺陷并不改变NK细胞表面活化性受体或者抑制性受体的表达水平。此外,通过CD107a检测证实自噬不影响到NK细胞的杀伤性颗粒外排功能。这些结果说明NK细胞杀伤功能的增强主要是由于穿孔素和颗粒酶B的表达增加,其具体分子机制还有待于进一步研究。
[Abstract]:Autophagy (Autophagy) is produced in eukaryotic cells. It is formed by two ubiquitin like binding systems (Atg12 and Atg8/LC3 binding systems), and the encapsulated intracellular components are transferred to lysosomes for degradation. NK cell (Natural killer cells) is an important member of the innate immune system and plays an indispensable role in anti-tumor and anti-infection immunity. The effect of autophagy activity of NK cells on the cytotoxicity of NK cells has not been reported at home and abroad. Therefore, in this study, autophagy gene Atg3 and Atg7 conditional knockout mice were used to explore the above contents. Using tamoxifen to knockout the Atg3 autophagy gene of Atg3f/f ER-cre mice and Atg7 autophagy gene of Atg7f/f UbiER-cre mice, we found that the killing ability of NK cells in the knockout group was significantly enhanced in vitro. And there are more cytotoxic perforin and granzyme B in the cell. The results also showed that the mice with autophagy deficiency had strong antitumor activity and prolonged survival time. Further studies showed that the differentiation, maturation and activation of autophagy deficient NK cells (IFN-y synthesis) did not change. At the same time, autophagy deficiency did not change the expression of activated or inhibitory receptors on the surface of NK cells. In addition, autophagy did not affect the efflux function of NK cells by CD107a detection. These results suggest that the enhancement of cytotoxicity of NK cells is mainly due to the increased expression of perforin and granzyme B. the specific molecular mechanism of the increase in the cytotoxicity of NK cells remains to be further studied.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R73-3

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