急性淋巴细胞白血病（ALL）细胞与骨髓微环境之间的相互作用在该疾病的发生、发展和治疗中至关重要。申请人前期研究发现，ALL细胞浸润并破坏正常骨髓微环境结构，化疗后ALL细胞分泌的炎性趋化因子（CCL3/CCL4）通过招募正常的骨髓细胞来重建动态演化微环境，藉此保护残留的ALL细胞。最近研究结果提示ALL细胞分泌的CCL3/CCL4对于其植入骨髓具有关键作用，但具体机制亟待研究。本项目拟采用离体外成像和全组织荧光染色技术分析移植后ALL细胞与骨髓细胞之间的三维时空定位关系；利用RNA-seq和CRISPR/Cas9等手段研究CCL3/CCL4介导骨髓微环境重塑以及活化的骨髓微环境维持ALL细胞生存和增殖的分子机制；通过ELISA和原位免疫染色等技术验证CCL3/CCL4与ALL病程进展的相关性。本项目将以全新的视角阐明ALL发病学的关键分子及骨髓微环境基础，为ALL的防治提供新思路和新靶点。

Studies have shown that the crosstalk between the cells of acute lymphoblastic leukemia (also referred to ALL) and bone marrow (BM) niche plays an important role in the occurrence, progress and treatment of ALL. Our latest study found that ALL cells infiltrate and destroy normal structure of BM niche after being transplanted. ALL cells rebuild an evolving niche by recruiting normal BM cells and secreting inflammatory cytokines (CCL3/CCL4) after chemotherapy to protect the residual ALL cells. Recently, our results suggest that CCL3/CCL4 secreted by ALL cells play a key role in the implantation of bone marrow. However, the mechanism is urgent to explore. Based on the success of building an ALL mouse model, this project is plan to analyze the relationship of three-dimensional spatio-temporal location between the cells of ALL and BM niche through using ex vivo imaging and whole-mount tissue staining technique. Meanwhile, the mechanism of remodeling of BM niche mediated via CCL3/CCL4 and the survival and proliferation ALL cells maintained by the activation of BM niche were investigated by using RNA-seq, CRISPR/Cas9 and so on. Furthermore, the correlation of CCL3/CCL4 and the pathogenesis of ALL patients were verified through ELISA and in situ immunohistochemical staining techniques. This project will clarify the key molecules and BM niche foundation of ALL pathogenesis with a new perspective, and provide a new target for the prevention and treatment of ALL.