microRNAs调控IL-9介导的免疫耐受机制在慢性淋巴细胞白血病中的研究

慢性淋巴细胞白血病(CLL)患者体内存在T、B细胞构成比例、免疫耐受及免疫调节功能紊乱，但其机制仍不甚清。已证实miR-155及miR-21参与CLL免疫调控机制。我们的前期实验发现IL-9在CLL患者中高表达，STAT3与STAT6能够调节IL-9的产生及活性，前期生物信息学分析证实miR-155、miR-21与STAT3、STAT6及IL-9之间存在密切联系。因此我们设想miR-155、miR-21可能通过STAT3、STAT6的介导来实现对IL-9表达的调控，进而在CLL免疫耐受中发挥作用。本课题拟通过探讨CLL中miR-155、miR-21与STAT3、STAT6对于IL-9分泌和功能发挥的影响，揭示CLL细胞中免疫紊乱及免疫耐受的确切机制，通过动物实验进一步验证miRNAs对CLL的免疫调控，阐述IL-9可能作为逆转CLL免疫耐受靶标的可能性，为CLL治疗提供理论依据。

Background: B-cell chronic lymphocytic leukemia (CLL) is a disease caused by a clonal expansion of small, mature B lymphocytes. It is associated with a profound immune defect and immune reconstitution. MicroRNA (miR), such as miR-155 and miR-21, are emerging as important gene expression regulators often involved in a variety of pathogenesis such as cancers and autoimmunity. Our unpublished data have found that there was high levels of IL-9 in sera of CLL patients. Signal transducers and activators of transcription (STAT) proteins are the principle signaling proteins for many cytokines and growth factors, thereby play a critical role in regulating immune cell homeostasis, differentiation and cellular functions.Former studies have demonstrated that STAT3 and STAT6 contributed to the secretion and function of IL-9. ..Objective: In this study, we aim to explore the effects of microRNAs on IL-9 mediated immunosuppression of CLL, establish the interaction network of miR-155, miR-21, STAT3, STAT6 and IL-9 in immune tolerance of CLL. ..Methods: Expression of miR-155, miR-21, STAT3, STAT6 and IL-9 both in CLL cell lines and primary CLL cells are detected by both qRT-PCR and Western-Blot. The proportion of IL-9 secreting cells (Th2, Th9, Th17 and Treg) in CLL is measured by FACS. To explore the effects of miR-155 and miR-21 on CLL cells and IL-9 secreting cells, they are isolated and transfected with miR-155 and miR-21, respectively. The promoter and inhibitor of STAT3 and STAT6 are used to validate the roles of STAT3 and STAT6 in the production and function of IL-9. The effects of microRNA in CLL development are further studied by animal model with CLL...Expected results: (1) To elucidate the expression of miR-155, miR-21, STAT3, STAT6 and IL-9 in CLL, analyze their relationship with clinical characteristics, explore their potential for clinical application as diagnosis, therapy response and prognosis biomarkers. (2) To demonstrate the effects of miR-155 and miR-21 on IL-9 secreting cells and involved mechanisms, explain the importance of STAT3 and STAT6 in this process,and establish miR-155 and miR-21 related interaction network in IL-9 production and function. (3) To discuss the importance and possibility of miR-155, miR-21, STAT3, STAT6 and IL-9 in CLL diagnosis, treatment and prognosis and provide novel insight for the immune tolerance and possible therapeutic strategy of CLL.