Omentin-1调控间充质干细胞炎症免疫调节功能促进心肌缺血/再灌注损伤修复的机制研究

Inflammatory immune responses play an important role in aggravating myocardial ischemia/reperfusion injury (IRI) and effective interventions are still lacking. Mesenchymal stem cells (MSCs) have the ability to regulate inflammation and immune processes but their ability is not constitutive; instead it has plasticity which is controlled by their microenvironment. Recently it was found that omentin-1 in the myocardial microenvironment was significantly reduced during myocardial infarction. We have demonstrated for the first time that omentin-1 can promote the survival of MSCs but its role in the inflammatory immune regulation of MSCs remains to be revealed. Preliminary experiments found that omentin-1 could enhance the ability of MSCs to repair IRI and enhance the ability of MSC-derived exosomes to inhibit the activation of NLRP3 inflammasome in target cells. Moreover, high-throughput screening and target validation experiments indicated that omentin-1 up-regulated the expression of miR-30e-3p associated with NLRP3 in exosomes. Therefore we hypothesize that omentin-1 is the key to enhance anti-inflammatory and immunoregulatory effects and tissue repair capacity of MSCs by increasing the level of miR-30e-3p in MSC-derived exosomes and then targetedly inhibiting NLRP3 inflammasome activation in injured tissues. In this project we intend to elucidate that omentin-1 is an important myocardial microenvironment factor that enhances the anti-inflammatory and immunoregulatory effects of MSCs and to reveal its molecular mechanisms through in vitro and in vivo experiments. The proposed studies may provide new ideas for optimizing MSC treatment of myocardial infarction.

炎症-免疫反应是加重心肌缺血/再灌注损伤（IRI）的重要原因，仍缺乏有效的干预手段。间充质干细胞（MSC）具有炎症免疫调节能力，受控于所处微环境而具有可塑性。近期发现心梗时网膜素-1在心肌微环境中含量显著下降，我们首次证实网膜素-1可促进MSC存活，但对其炎症免疫调节能力的影响有待揭示。预实验表明网膜素-1可增强MSC修复IRI的能力，增强MSC来源外泌体抑制靶细胞NLRP3炎症小体活化的能力；高通量筛选及靶点验证提示网膜素-1可上调外泌体中与NLRP3相关的miR-30e-3p的表达。我们推测网膜素-1提高MSC外泌体中miR-30e-3p水平进而靶向抑制受损组织NLRP3炎症小体活化是其强化MSC炎症免疫调节能力、增强其组织修复作用的关键。本项目通过体内外实验阐明网膜素-1是调控MSC炎症-免疫调节能力的重要心肌微环境因子，并揭示其所依赖的分子机制，为优化MSC治疗心肌梗死提供新思路。

高糖诱导的内皮功能障碍是糖尿病血管并发症发生发展的关键起始因素。在2型糖尿病患者中，omentin-1被认为是一种新型内皮功能生物学标志物；然而，尚不清楚omentin-1对高糖诱导的内皮功能障碍是否存在直接的保护作用。在本研究中，我们分析了omentin-1对高糖诱导的离体小鼠主动脉组织环和主动脉内皮细胞功能障碍的影响。使用肌动描记法测量主动脉血管收缩反应性。蛋白印记法检测AMPK、PPARδ、AKT和eNOS以及内质网应激标记物的蛋白表达水平。活性氧和一氧化氮水平通过荧光探针法检测。我们发现omentin-1体外治疗减轻了高糖损伤后小鼠主动脉内皮依赖性舒张功能的受损程度。Omentin-1预处理降低了高糖诱导的内皮细胞中内质网应激及氧化应激水平并恢复了一氧化氮的含量。Omentin-1还有效降低了衣霉素诱导的内皮细胞中内质网应激反应水平，并减轻了小鼠主动脉内皮依赖性舒张功能的损害。此外，omentin-1增加了AMPK的磷酸化以及其下游的PPARδ蛋白的表达，同时也恢复了Akt和eNOS的磷酸化水平。Omentin-1的上述作用可被compound C和GSK0660所阻断。这些数据表明，omentin-1通过激活AMPK/PPARδ途径抑制内质网应激和氧化应激水平，增加一氧化氮含量来保护高糖诱导的血管内皮功能障碍。