TIM3在骨髓增生异常综合征发病机制中作用的研究

T cell immunoglobulin mucin domain 3 (TIM3) was highly expressed on leukemia stem cells, but not on normal hematopoietic stem cells (HSCs). Our team has extended that to MDS which is considered as pre-leukemia, and has found that increased TIM3+HSCs in MDS possessed aberrant differentiation, overproliferation and decreased apoptosis. Based on these results, we plan to observe the immunosuppression of TIM3+HSC through coculture with myeloid-derived suppressor cells (MDSCs，they can regulate anti-tuimor immunity) , and then we intent to transplant human TIM3+stem cells into severe combined immune deficiency(SCID) mice in order to explore whether human TIM3+stem cells could reconstitute in animal model. Finally, we will evaluate the effect of targeted therapy for MDS mice after injection TIM3/Gal-9 pathway antagonist. Together, we would like to find a candidate marker for elimination malignant clone cells and recovering anti-tumor immunity function in MDS.

近年骨髓增生异常综合征（MDS）的研究集中于恶性克隆和细胞免疫缺陷。课题组前期发现MDS患者体内造血干细胞高表达T细胞免疫球蛋白粘液素3（TIM3），且TIM3+干细胞具有分化异常、增殖过度和低调亡特征，同时与髓源性抑制细胞（MDSC，具调控抗肿瘤免疫功能）呈正相关。TIM3+干细胞是否为MDS患者体内恶性克隆细胞，通过何种机制诱导细胞免疫缺陷尚不清楚。本研究拟：1.通过TIM3+干细胞与MDSC体外共培养探索TIM3+ 干细胞是否可诱导细胞免疫缺陷；2.通过TIM3+干细胞接种于SCID小鼠验证其成瘤性；3.应用TIM3/Gal-9通路阻断剂，观察恶性克隆负荷和抗肿瘤免疫功能变化。以上研究将为MDS恶性克隆的早期识别和靶向治疗提供依据。

本课题组长期以来对MDS恶性克隆的早期识别进行了广泛且深入的研究，分别检测了CD47、CD123、CD96及TIM3等分子标志物，试图找到可以早期识别恶性克隆的生物学分子，为MDS的精准诊疗提供依据。本项目发现MDS患者骨髓干细胞高表达TIM3，且TIM3+干细胞数量与患者病情进展密切相关，进一步探索其生物学特征发现，该团细胞具有低分化、高增殖、低凋亡的恶性生物学特点，进而体外分选后培养发现：TIM3+干细胞与TIM3-干细胞及正常造血干细胞在形态学无显著性差异，但是其难以形成红系、粒单系集落，且细胞遗传学存在异常比例高于TIM3-干细胞，且TIM3+干细胞与MDSC共培养（该细胞群高表达TIM3的天然配体Gal-9）后凋亡率减低；最后于动物模型体内验证该团细胞的恶性生物学特点：人源性TIM3+干细胞在重度联合免疫缺陷小鼠（SCID）体内几乎难以分化为淋系或髓系细胞，当加入人源性MDSC后，MDSC又进一步加剧了TIM3+干细胞低凋亡、低分化的特点，起到“推波助澜”的作用。.总之，本课题组初步证实了MDS患者TIM3+干细胞极可能是恶性克隆性细胞，为早期识别真正的MDS克隆及精准靶向治疗提供了理论依据。