输血是创伤救治的重要手段，但输注陈旧红细胞存在加重创伤病情的风险。一般认为陈旧红细胞释出的血红素通过刺激促炎介质表达、叠加增强创伤后炎症加重创伤进展，但新近发现炎症自限调节障碍才是创伤后炎症失控的关键。我们近期发现血红素可干扰炎症自限，这伴随炎症“刹车”分子ALX下调。预实验提示血红素在转录后水平调节ALX；芯片及生物信息学分析发现血红素可诱生miR-144-3p、而ALX可能是后者的抑制靶点。因而，血红素通过miR-144-3p下调ALX并干扰炎症自限可能是陈旧红细胞加重创伤病情的新机制。为证实该假说，本项目将首先证实miR-144-3p下调ALX是血红素干扰炎症自限的重要机制；进而通过染色质免疫共沉淀等方法揭示血红素诱生miR-144-3p及miR-144-3p下调ALX的分子机制；最后在模拟临床的创伤-输血动物模型中验证上述机制。本项目旨在揭示陈旧红细胞促进创伤后炎症失控的新机制。

Transfusion is an essential measure of trauma therapy. However transfusion old stored blood has risk of aggravating progression of trauma. It is generally recognized that hemin released from old stored blood aggravats trauma process through stimulation of pro-inflammatory mediators and superimposing enhancement of post-traumatic inflammation. It is newly discovered that hemin can disturb imflammatory self-limiting process, which will follow by decreased expression of lipoxin A4 receptor (ALX), which is an inflammatory “stop”signal. Our data of pre experiment indicated that hemin regulated expression of ALX post-transcriptionally. Results of bioarray screen and bioinformatic analysis indicated that hemin could induce expression of miR-144-3p, which targeted ALX gene and down-regulated its expression. Therefore, hemin inhibited ALX expression through miR-144-3p and restrained inflammatory self-limiting process, which might be the new mechanism of aggravating trauma progression after transfusion old stored RBC. To test this hypothesis, firstly, this project will confirm that down-expression of ALX by miR-144-3p is the important mechanism of disturbance of self-limiting by hemin; secondly, molecular mechanism of hemin inducing miR-144-3p and miR-144-3p down-regulating ALX was investigated with molecular biotechnology methods such as chromatin immunoprecipitation (Chip-assay); finally, traumatic rat animal model which simulated clinical situation was used to validate the above mechanism. This project was aimed to discover the new mechanism of old stored RBC promoteing uncontroled inflammation after trauma.