IGF-1自分泌/旁分泌协同Tregs过继免疫治疗T1D及其分子影像学监测的研究

Adoptive immunotherapy by transfusion autologous regulatory T cells (Tregs) is the research highlights of type 1 diabetes (T1D) individualized immunotherapy in recent years. However, there are still several defects, as well as the absence of non-invasive detection methods for in vivo monitoring the fate of Tregs and assessing the state of beta cells for a long term. Recent studies found that insulin-like growth factor-I (IGF-I) can regulate the immune function to stimulate the proliferation of Tregs, to maintain the immune suppression effects of Tregs and to prompt their targeting migration in vivo by an autocrine/paracrine manner. Combining with early research work, we propose to use a novel baculovirus-sleeping beauty transposon vector system mediating high efficient and long-term expression of IGF-I and sodium iodine symporter (NIS) transgenes in Tregs, through which IGF-I will regulate the Tregs, enhancing their biology characteristics, and the migration, distribution and proliferation of Tregs will be monitored by NIS reporter gene imaging. At the same time, the radionuclide labelled lixisenatide will also be used to monitor the beta cells for exploring the intrinsic mechanism and assessing the therapeutic effect of synergetic therapy of T1D by Tregs adoptive immunotherapy combined with IGF-1 autocrine/paracrine. Furthermore, by comparing the therapeutic effect with other immunotherapy methods, we will provide novel and potential strategies for Tregs adoptive immunotherapy as well as their therapeutic effect monitoring in T1D.

通过回输调节性T细胞(Tregs)的过继免疫疗法是近年来个体化免疫治疗1型糖尿病(T1D)的研究热点，但目前的治疗方法仍存在不足，且缺少无创的活体检测手段来长期监测Tregs的命运和评估β细胞的状态。研究发现，胰岛素样生长因子-I(IGF-I)能够以自分泌/旁分泌的方式发挥免疫调控功能，刺激Tregs增殖、维持免疫抑制功能及促使其靶向移行。结合前期研究基础，我们拟利用杆状病毒-睡美人转座子新型载体介导IGF-I和钠碘同向转运体(NIS)在Tregs中长期高效表达，以实现IGF-I对Tregs的调控，增强其生物学特性，并利用NIS报告基因监测Tregs的移行、分布和数量；同时利用核素标记的lixisenatide进行β细胞的核素显像，以探索IGF-I自分泌/旁分泌协同Tregs过继治疗T1D的内在机制和评估其疗效，并通过与其他治疗方法的比较，为Tregs过继治疗T1D及其疗效监测提供新策略。

胰高血糖素样肽-1（glucagon-like peptide 1, GLP-1）及其类似物在糖尿病等多种疾病的治疗中展示其良好的应用前景，其受体——胰高血糖素样肽-1受体（glucagon-like peptide 1 receptor, GLP-1R）作为报告基因也具有潜在的临床应用价值。本研究首先构建了带有钠碘同向转运体（sodium-iodide symporter, NIS）报告基因的和睡美人转座子（Sleeping Beauty 100× transposon, SB100×）系统的稳转杆状病毒（baculovirus, BV），研究显示该稳转BV可实现转基因长期、稳定和高效的表达；进一步体内外研究证明，稳转BV介导的核素报告基因显像可实现在活体条件下对移植细胞的长期监测，并且对移植干细胞具有较高的生物安全性。在此基础上，将人GLP-1R基因构建于瞬转或稳转的BV中，将GLP-1R作为核素报告基因进行了体外生物学特性以及18F标记GLP-1类似物小动物PET分子显像的研究，首次提出和验证了GLP-1R作为核素报告基因进行分子显像的可行性，为GLP-1R作为核素报告基因的应用奠定了实验基础。动物GLP-1R PET显像发现，胰腺等组织器官的GLP-1R表达水平与年龄的相关性可能与雄激素水平密切相关，进一步研究揭示了雄激素可结合于GLP-1R基因启动子区域的雄激素受体结合位点，上调GLP-1R基因转录的分子机制，对深入了解糖尿病甚至肥胖的发病机制和提供新的治疗策略均具有重要的临床价值。并通过建立类固醇性糖尿病（steroid diabetes mellitus, SDM）大鼠模型，并与T2DM动物模型对照，通过小动物18F-FDG PET/CT显像观察大鼠骨骼肌等器官的糖代谢及胰岛素抵抗状况，揭示了SDM与T2DM在发病机制中存在差异，为临床提供了新的认识。