炎性趋化因子介导骨髓微环境重塑在ALL发病中的作用及机制研究

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.

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。

本项目拟探讨炎性趋化因子介导骨髓微环境重塑在急性淋巴细胞白血病（简称急淋，ALL）发病中的作用及机制。我们前期研究发现，ALL细胞移植后浸润并破坏正常的骨髓微环境结构，化疗后ALL细胞分泌的炎性细胞（或趋化）因子（CCL3/CCL4）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。在骨髓中ALL细胞与造血干细胞（HSC）竞争性占据空间有限的微环境，而且两者的数量以及自我更新、增殖与分化能力也受到微环境的严格调控。因此，ALL发病和治疗过程中白血病细胞如何启动和改造正常的骨髓微环境增强自身竞争能力或利于自身的生存、增殖和浸润是ALL发病学和治疗学的关键。本项目重点探讨：1）化疗诱导ALL炎性细胞因子表达的分子机制；2）化疗诱导微环境影响正常造血重建的功能和机制。我们的研究表明：靶向病理性骨髓微环境的形成是ALL防治的关键。主要发现包括：1）我们发现化疗诱导炎性细胞因子表达的新机制：AMT-TRAF6-NF-κB信号通路调控化疗后ALL的炎性细胞因子的表达。2）我们发现化疗诱导微环境影响正常造血重建功能的新机制：病理性骨髓微环境主要组分间充质干细胞化疗后下调表达HSC维持的细胞因子，导致HSC重建造血能力降低。本项目研究成果证实阻断ALL细胞中ATM依赖的NF-κB信号通路能够克服来自骨髓微环境对化疗后微小残留白血病细胞的保护作用，显著提高ALL的化疗效果，对临床后期开展ALL联合治疗具有重要意义。同时通过改善骨髓微环境，从而增加化疗后HSC的造血重建能力，有望提高ALL的治疗效果。