蛋白激酶MK2调控嗜中性粒细胞活化介导肝脏缺血再灌注损伤机制与新型药物靶标

Liver ischemia reperfusion (I/R) injury is an important cause of liver transplantation failure. So far, there are no effective treatments. Therefore, it is vital to understand the fundamental mechanisms and find an effective drug target. Neutrophils are key inflammatory cells associated with liver I/R injury. However the mechanism of neutrophil activation and the role of neutrophils in liver I/R injury haven't yet been fully elucidated. MK2(MAPK-activated protein kinase 2) is a Ser/Thr protein kinase. Based on our novel preliminary data that MK2 is required for liver I/R injury, MK2 deficient neutrophils produced less superoxide and MK2 directly phosphorylates p47phox Ser277, we propose that MK2 modulates liver I/R injury through regulating neutrophil activation. Therefore, the pathological role of MK2 in liver I/R injury and neutrophil activation will be demonstrated. In addition, this studies will also determine the molecular mechanism of MK2 regulating superoxide generation via phosphorylation of p47phox Ser277 and evaluate whether MK2 inhibitor III will be able to alleviate liver I/R injury. Taken together, our findings will not only contribute to the fundamental theory basis of liver I/R injury, but also provide a potential drug target for treating liver transplantation-induced liver injury.

肝脏缺血再灌注损伤是导致肝脏移植失败的重要原因，尚无有效治疗手段，因此阐明其发病机理和发现新型药物靶标是亟待解决的关键问题。嗜中性粒细胞是参与肝脏缺血再灌注损伤的关键炎症细胞，其活化机制及在肝脏缺血再灌注损伤中的作用机理尚未完全阐明。MK2是一种丝氨酸/苏氨酸蛋白激酶。前期研究首次发现MK2促进小鼠肝脏缺血再灌注损伤，MK2缺失嗜中性粒细胞生成超氧阴离子明显减少，并首次鉴定MK2直接磷酸化p47phox Ser277位点。本研究拟阐明MK2促进肝脏缺血再灌注损伤的病理机制；探明MK2在嗜中性粒细胞活化中的重要作用；重点探讨MK2通过磷酸化p47phox Ser277 位点调节超氧阴离子产生的分子细节；评价MK2抑制剂III治疗肝脏缺血再灌注损伤的新型药物靶标作用。最终阐明MK2如何通过调控嗜中性粒细胞活化介导肝脏缺血再灌注损伤的分子机制，同时为治疗肝脏移植损伤提供一个潜在的新型药物靶标。

肝脏缺血再灌注损伤是肝脏移植失败的重要原因，尚无有效治疗手段和药物，因此阐明其发病机制和发现新型药物是亟待解决的关键问题。本项目阐述嗜中性粒细胞参与调控肝脏缺血再灌注损伤，抗Gr-1（1A8）抗体可以降低肝脏缺血再灌注损伤，证实嗜中性粒细胞参与调控肝脏缺血再灌注损伤。蛋白激酶MK2敲除小鼠肝脏缺血再灌注损伤减弱，MK2缺失嗜中性粒细胞产生的ROS降低，发现MK2影响p38 MAPK和Akt的磷酸化。通过激酶活性分析，鉴定出MK2直接磷酸化p47phox Ser 329位点，并证实该位点调控超氧阴离子产生。此外，项目还构建髓系特异性敲除MK2小鼠，证实MK2通过嗜中性粒细胞发挥体内活性，促进肝脏缺血再灌注损伤。本项研究阐明了MK2如何通过调控嗜中性粒细胞活化介导肝脏缺血再灌注损伤的分子机制，为治疗肝脏移植损伤提供潜在药物靶标。..本项目在基金委的资助下，培养博士研究生7名，1名已经毕业，培养硕士研究生8名，毕业1名；发表SCI研究论文7篇，其中1篇为J Mol Cell Biol封面文章（IF：8.223），1篇发表在著名免疫学杂志Journal of Immunology；本课题主要研究内容已经完成，论文目前投稿Hepatology（IF：13.246），处于审稿状态；在本项目资助下，参加多次国际国内会议，并做大会报告。总之，本项目进展顺利，感谢基金委对于本项目的资助，待有更多成果后，继续汇报。