Ang-1-TIE-2-miR-9信号轴调控间充质干细胞移植治疗重症急性胰腺炎的分子机制研究

Severe acute pancreatitis(SAP),the clinical treatment of which is not satisfying, do great harm to the patients. It is believed at present that mesenchymal stem cells(MSCs) has a potential capability in curing SAP. We observed in the previous experiments that MSCs with the transfection of angiopoietin-1(Ang-1) gene can obviously promote the repair of the pancreas after SAP and Ang-1/TIE-2 can positively regulated miR-9 expression, which is closely related to the treatment efficacy. However, how Ang-1/TIE-2 regulates the miR-9 expression and the role of miR-9 playing in the process has not yet been clarified. Therefore, based on our previous study of MSCs treating SAP, we design this project using techniques such as confocal laser and molecular cloning to make a further study on: ①The mechanism of Ang-1/TIE-2 axis regulating miR-9 expression of MSCs; ②The functional influence of MSCs with the high expression of miR-9 to endothelial cells, pancreatic acinar cells, mononuclear cells and its mechanism; ③The possible signaling pathways of miR-9 promoting MSCs to treat SAP. The aim of this study is to further reveal the mechanism of Ang-1/TIE-2/miR-9 axis regulating MSCs to repair pancreatic tissue of SAP after the transplantation of MSCs and hoping to provide a new target point for the treatment of SAP.

重症急性胰腺炎（SAP）对患者危害甚大，临床治疗效果不佳。目前认为间充质干细胞（MSCs）移植具有治疗SAP的潜能。我们前期实验观察到，转染血管生成素-1（Ang-1）基因的MSCs移植治疗SAP能明显促进胰腺修复，Ang-1/TIE-2能够正向调控miR-9表达水平，且与治疗效果密切相关，但Ang-1/TIE-2如何调控miR-9及miR-9发挥作用的机理尚不清楚。因此，我们拟在以往对MSCs移植治疗SAP的研究基础上，应用激光共聚焦、分子克隆等技术，采用离体/在体实验，深入研究:①Ang-1/TIE-2轴调控MSCs内miR-9表达的机理；②高表达miR-9的MSCs对内皮细胞、胰腺腺泡细胞和单核细胞功能影响及机理；③miR-9促进MSCs修复胰腺损伤的可能信号通路。本研究旨在进一步揭示Ang-1/TIE-2/miR-9轴调控MSCs修复胰腺损伤的机理，亦有望为SAP的治疗提供新靶点。

重症急性胰腺炎（SAP）对健康危害甚大。由于缺血敏感且组织自身代偿能力较差，早期周围血管内皮的损伤所引起的胰腺微循环障碍，对疾病的进展有着不可忽视的作用。因此，在减轻细胞损伤、及时控制炎症/免疫反应的同时应加强胰腺损伤血管的修复。miR-9是一种古老且保守的小分子RNA，具有抗炎、促血管生成的作用。我们前期的研究发现血管生成素-1（Angiopoietin-1，Ang-1）基因修饰的骨髓间充质干细胞（BMSCs）能够通过 Ang-1/ TIE-2 途径促进miR-9 表达，加速胰腺损伤后修复，但其具体机制尚不明确。本研究中，我们利用病毒包装工程对BMSCs进行miR-9基因的修饰/拮抗，移植治疗大鼠重症急性胰腺炎，分析其对组织间血管内皮细胞（VECs）和胰腺腺泡细胞（PACs）的功能影响，及其相关的细胞/分子机理。结果表明miR-9+BMSCs能够明显改善胰腺炎的炎症程度，诱导损伤组织间血管生成。进一步研究表明，miR-9-BMSCs向VECs或损伤的胰腺组织释放miR-9，一方面通过激活PI3K/AKT通路促进组织微血管生成，另一方面通过抑制RIPK1/RIPK3/MLKL通路减少胰腺腺泡细胞坏死性凋亡，发挥抗炎和修复作用。以及，对BMSCs移植治疗SAP机制研究过程中我们还发现1. BMSCs通过激活PI3K/AKT/mTOR通路抑制细胞自噬，改善SAP引起的多器官功能衰竭2. BMSCs可以上调组织/血清中血红素氧合酶-1（HO-1）的表达水平，发挥抗炎抗氧化作用。此外，在联合治疗胰腺炎方面，我们发现联合N-乙酰半胱氨酸/白藜芦醇能够增强BMSCs对SAP的治疗效果。