miR-16调控NKG2D表达的分子机制及其对T/NK细胞功能影响的意义

MiR-16 as a tumor suppressor gene, its biological activity has attracted wide study. However, miR-16 expression of T and NK cells and its regulation mechanism is poorly understood. We previously confirmed that the expression of NKG2D was regulated by miR-16, but the molecular mechanism of NKG2D expression regulated by miR-16 and how NKG2D expression level affects function of T/NK cells remains to be elucidated. In this project whether miR-16 regulates the expression of NKG2D of resting and activated T/NK cells directly or indirectly will be firstly analyzed. Variations of miR-16 expression in CD8+T, CD4+ T, and NK cells by stimulations with different cytokines and their mechanisms will also be studied. Finally how miR-16 expression level affects function of CD4+NKG2D+ T cells in MICA+ tumors, function of NK cells, and inflammation mediated by CD8+ T cells will be observed. This project will not only richen the molecular mechanism of NKG2D expression regulated by miR-16, but also expand the understanding of biological effects of miR-16. The study would also provide more experimental data for development of clinically therapeutic drugs based on miR-16.

miR-16作为抑癌基因之一，其生物学活性受到广泛关注，但miR-16在T/NK细胞的表达特点及其调控机制，目前知之甚少。课题组初步证实NKG2D的表达受到miR-16调控，然而miR-16调控NKG2D表达的分子机制、以及NKG2D被调控表达后对T/NK细胞的功能影响期待明确。本项目拟首先分析静息和活化的T/NK细胞内，miR-16主要通过直接还是间接方式调控NKG2D表达；并观察不同细胞因子刺激后，CD4+T、CD8+T和NK细胞miR-16表达的变化及其转录调控机制；最后阐明miR-16通过调控NKG2D表达，对MICA+肿瘤微环境CD4+NKG2D+T细胞、NK细胞免疫功能的调节，以及对CD8+T细胞介导炎症反应的影响。本研究不仅从理论上丰富淋巴细胞NKG2D表达调控的分子机制，进一步拓展对miR-16生物学作用的认识，还为临床上基于miR-16开发相关治疗药物进行充分的前期论证。

miR-16作为抑癌基因之一，其在T/NK细胞的表达特点及其作用机制，目前知之甚少。. 本项目首先利用双荧光素酶报告实验，明确miR-16可直接结合NKG2D基因的3’-UTR，在此基础上通过引进的miR-15a/16基因敲除小鼠及自行制备的miR-15a/16转基因小鼠，分析miR-15/16过表达对CD4+NKG2D+T细胞、CD8+T细胞、NK细胞和调节性B细胞活性的调节，并观察该调节作用是否参与结直肠癌和DSS诱导小鼠结肠炎的进展。. 结果发现：miR-16缺失可诱导调节性CD4+NKG2D+T细胞的产生，但过表达miR-16对静息状态CD4+NKG2D+T细胞无明显影响；MiR-16低表达的调节性CD4+ NKG2D+ T细胞促进结肠癌的进展。miR-16缺失可促进CD8+T细胞表达NKG2D，促进DSS-诱导结肠炎的发生；过表达miR-16对静息CD8+T细胞活性无明显影响，但抑制CD8+T细胞的活化。尽管miR-15a/16缺失的小鼠具有抑制肿瘤生长的活性，但与NK细胞无关。miR-15a/16缺失可诱导CD19+TIM-1+调节性B细胞的产生，其机制依赖于STAT3的表达上调及其活化。. 本研究揭示机体在机体肿瘤或炎症状态下，T/B细胞内miR-16的表达发生动态变化，并调节T/B细胞的活性。干预T/B细胞内miR-16的表达水平可用于肿瘤或炎症性疾病的治疗。