多发性骨髓瘤exosome在骨髓微环境中介导信号传递促进骨破坏的作用研究

The interaction between multiple myeloma(MM) and bone marrow environment is one of the important factors in MM pathology. Osteolytic lesion is common and characteristic clinical manifestation in MM. The unbalance of bone remodeling induced by bone marrow environment is the important pathogenesis. However, the precise pathogenesis remains unclear. Our previous study detected that there were cell-free microRNAs (miRNAs), which could be encapsulated in exosomes released from cells. Human miRNA microarrays were used to determine the different expression of miRNAs between MM patients and normal individuals. We validated of array results and detected the miRNAs highly enriched in exosome. This study will predict the potential target genes of the miRNAs and explore whether exosome can transfer messages between MM cells and bone marrow stromal cells (BMSCs) from clinical、cell and animal levels. Whether the exosome-mediated miRNAs transfer can enhance osteoclast formation and function to promote bone disease. This study will not only create a wider angle view of miRNA, but also help to develop new therapy strategies for MM bone disease. Furthermore, this study will provide the possibility of using exosome as a target for myeloma bone disease treatment.

多发性骨髓瘤(MM)细胞与骨髓微环境相互支撑是MM重要发病机制之一。溶骨性破坏是MM常见且特征性临床表现，骨髓微环境介导的骨重塑失衡是溶骨病变产生重要机制，但目前对机制认识仍不全面。前期研究发现MM存在细胞外miRNA，胞外的miRNA保护性封装于MM细胞分泌的外来体（exosome）中。我们已通过基因芯片筛选并进一步验证出MM患者与健康对照的差异miRNA，从中筛选出exosome中高表达的miRNA。本课题拟进一步采用生物信息学方法预测exosome中差异miRNA的靶基因，从临床、细胞和动物模型水平探讨exosome是否为MM细胞和骨髓基质细胞（BMSC）间信息交流的新媒介，MM细胞通过exosome向BMSC传递miRNA群，促进破骨细胞生成并增强其功能，导致骨病变。本研究不仅为认识miRNA开辟了更广的角度，也为开拓MM骨病治疗新策略、研发针对exosome的靶向治疗提供依据。

多发性骨髓瘤(MM)细胞与骨髓微环境相互支撑是MM重要发病机制之一。溶骨性破坏是MM常见且特征性临床表现，骨髓微环境介导的骨重塑失衡是溶骨病变产生重要机制，但对机制认识仍不全面。既往认为微小RNA(miRNA)主要在细胞内发挥作用，由于在细胞外广泛存在着RNase酶，可以迅速降解miRNA，所以在细胞外它难以存在和发挥作用。研究发现，细胞外液中的miRNA可保护性地被封装于一种称为“外泌体(exosome)”的亚细胞结构中，细胞外稳定存在的miRNA有着极其重要作用。本研究从临床、细胞和动物模型水平探讨循环miRNA是否可作为MM潜在的疾病标记，exosome是否为MM细胞和骨髓基质细胞(BMSC)间信息交流的新媒介，MM细胞通过exosome向BMSC传递miRNA群，促进破骨细胞生成并增强其功能，导致骨病变。结果提示：(1)血浆miR-483-5p在MM患者中表达显著增高；miR-483-5p的水平与ISS分期和骨病变相关，与D-S分期、年龄、性别、M蛋白类型无关；miR-483-5p 高表达的患者无进展生存时间更短。(2)MM细胞来源的exosome可被BMSC内化；分离MM细胞来源的exosome与BMSC共培养，发现SIRT1表达水平较对照组下降，XBP1s 和RANKL较对照组升高，XBP1s乙酰化水平增加。(3)MM细胞来源的exosome与BMSC共培养液代替RANKL因子，对外周血单个核细胞进行体外诱导培养破骨细胞，加入exosome组出现较多的多核TRAP染色阳性的细胞，数量与对照组有显著差别；骨片表面有明显的骨吸收陷窝形成。(4)分别采用exosome+MM细胞株和MM细胞株建立SCID-MM小鼠模型，发现exosome+MM细胞株小鼠骨骼破坏明显。本研究通过分析MM患者血浆miRNA表达谱，筛选出与MM发生发展和骨病相关的分子标签，且具有预后指导意义，具有突破性价值。阐明MM细胞以exosome为媒介向微环境中的BMSC传递miRNA分子群，从而导致溶骨性骨病。这一MM骨病机制的发现，为开拓MM骨病治疗新策略、研发针对exosome的靶向治疗提供依据，具有重要的科学意义及临床应用前景。