新型急性移植物抗宿主病标记hsa-miR-586 / hsa-miR-153对吲哚胺2,3-双加氧酶的靶向调控研究

As a major complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT), acute graft-versus-host disease (aGVHD) post transplantation seriously affects the long-term survival of patients. Early diagnosis and treatment are very essential to the outcomes of patients with aGVHD. Predicting and pre-warning system is the key point to improve the curative effects. Thus, elucidation of the molecular regulative mechanism that contributes to pathogenesis of aGVHD would benefit to find new interventive targets. Indoleamine 2, 3-dioxygenase (IDO) can catalyze the initial rate-limiting step in tryptophan degradation in the kynurenine pathway to inhibit conventional T cell proliferation and induce immunosuppressive effect, therefore control the development of aGVHD. Up to now, the accurate mechanism of IDO regulation is still unclear. Our previous work demonstrated that the plasma IDO level was associated with the severity of aGVHD. A set of microRNAs (miRNAs) in peripheral blood,which might be the new biomarkers of aGVHD,have been screened out through miRNA array. Based on the data of bioinformatics, the expression of IDO might be regulated by some of these miRNAs. The aims of this study are: 1) to investigate the correlation between miRNA-586 & miRNA-153 and IDO expression during the process of aGVHD; 2) to further confirm the regulation of miRNA-586 & miRNA-153 on IDO gene through in vitro experiments. Therefore, it would provide the convincing evidence to support that specific miRNA expression profile is of predictive value for occurrence of aGVHD and these miRNAs would be involved in aGVHD regulation by its post-transcriptional regulation of IDO. This might provide the new potential therapeutic targets for treatment of aGVHD.

急性移植物抗宿主病（aGVHD）是异基因造血干细胞移植后影响患者预后的重要因素，尽早诊疗是改善其疗效关键。吲哚胺2,3-双加氧酶（2,3-IDO）是催化色氨酸代谢的限速酶，可抑制效应T细胞增殖并诱导免疫耐受而控制aGVHD。目前其调控机制尚不明确。我们前期工作发现血浆中2,3-IDO水平与aGVHD相关，并通过基因芯片筛选出可能为aGVHD新型生物学标记的外周血微核糖核酸（miRNA），生物信息学研究推测2,3-IDO可能受其中特定miRNA调控。本研究拟通过探讨miR-586及miR-153与2,3-IDO及aGVHD状态的相关性，体外功能试验明确miR-586及miR-153对2,3-IDO的调控作用；来鉴定对aGVHD有预警预测意义的miRNA，阐明其对2,3-IDO的转录后调控作用，以及该作用在aGVHD发病转归中的角色，为临床实现新的aGVHD"预警-干预"方法提供可能的新靶点。

异基因造血干细胞移植（Allo-HSCT）是白血病等血液恶性肿瘤有效乃至唯一的治疗手段，但移植物抗宿主病（GVHD）是影响患者预后和生存质量的重要因素。及早地诊断与治疗会明显改善病人的预后，实现对疾病预警监测进而早期防治是提高aGVHD疗效的关键，阐明参与发病的分子调控机制也有利于为干预找到新靶点。吲哚胺2,3-双加氧酶（IDO）通过催化色氨酸代谢抑制效应T细胞增殖、诱导免疫耐受从而控制aGVHD。目前调控IDO的机制尚不明确。我们前期工作发现患者血浆中IDO水平与aGVHD相关，微核糖核酸（miRNA）芯片已筛选出若干种与aGVHD相关的外周血循环miRNA，而生物信息学研究推测IDO表达可能受其中几种miRNA调控。本项目研究成果发现了对疾病具有早期预警意义的生物学标记——两条新型aGVHD生物学标记miRNA-153和miRNA-586，其表达随aGVHD发生、发展而变化，并能移植后早期通过微创形式检测达到预测aGVHD发生的目的，此外本研究还发现了miRNA-153可直接靶向调控发挥免疫耐受作用的重要分子——IDO而参与aGVHD发病，并通过小鼠移植模型进一步证实了miRNA-153在GVHD发病中的作用以及对IDO表达的影响。该结果有助于探讨针对GVHD早期特异性信号通路的靶向干预方法，阻断炎性细胞因子风暴，促进GVHD“早期预警-早期干预”新治疗方法的建立，有望进一步改善Allo-HSCT患者预后，节省患者在控制aGVHD的医疗消费，优化并完善白血病等血液系统疾病的治疗体系。