Nap-Cur-NO水凝胶优化微环境递释Tβ4-MSCs来源外泌体促进梗死心肌再生

Stem cells transplantation therapy is a promising treatment to the death myocardium after infarction. However, the poor survival rate, safety issues and the incompletely understood mechanisms restrain its further application in clinic. Currently, the exosomes which derive from stem cells drawing greatly attention because of its significant treatment outcomes, the stem cells likely regeneration ability and its flexible availability. We have reported a combined nitric oxide and curcumin (Nap-Cur-NO) releasing hydrogel which is able to facilitating angiogenesis and improving heart function after myocardial infarction. In this study, we intend to applying this cardiac beneficial hydrogel as the carrier of exosomes which come from the Tβ4 angiogenesis factor modified MSCs, and investigating the role of the Nap-Cur-NO hydrogel loaded Tβ4-MSCs derived exosomes in the repairment infarction region. Through molecular biology and bioinformatics analysis methods, we aimed to explore the key targets and possible signaling pathways associated with this coordinated treatment which may provide a newly stem cells paracrine based approach for AMI therapy.

干细胞治疗为心肌梗死（AMI）后心肌再生修复带来曙光，然而移植的干细胞在缺血缺氧的微环境中存活率低、有效性及机制仍备受争议。干细胞来源exosomes移植治疗可显著改善AMI心肌损伤，发挥类似干细胞样的修复作用，更具潜力。申请人前期已成功研制出一种能促进血管新生、心肌修复、同时释放NO及姜黄素的天然活性多肽Nap-Cur-NO水凝胶，现拟将其作为exosomes 的输送载体，优化微环境；同时为促进伴随快速血管化的心肌再生，使用促血管形成因子Tβ4修饰MSCs，后再分离提纯获得Tβ4-MSCs来源的 exosomes。在小鼠心梗模型中探讨Nap-Cur-NO水凝胶携带exosomes对梗死心肌的再生修复作用，运用分子生物学及生物信息学分析方法，探索该水凝胶-exosomes复合体修复AMI的关键靶点及其可能的信号通路，为生物活性材料联合干细胞活性组分治疗AMI 提供有效的理论支持和保证。

本课题为了模拟干细胞的旁分泌和生物活性，我们成功地制备了一种人工干细胞（Tβ4-ASCs）。其通过使用微流体技术将功能性外泌体封装在微球内，可以持续释放Tβ4外泌体，且很好的克服了外泌体高清除率的缺点。在体内外研究发现，Tβ4-ASCs不断释放的Tβ4-EXO可显著增强小鼠冠脉内皮细胞（MCAECs）的血管生成能力，提示在冠状动脉侧支化中发挥重要作用。此外，在心梗小鼠模型中证实，Tβ4-ASCs可以通过诱导冠状动脉分支的形成和改善心梗后的心功能。最后，在机制研究中，我们证明了Tβ4-ASCs来源的外泌体可以通过miR-17-5p/PHD3/Hif-1α通路增强冠脉内皮细胞的血管生成能力。简而言之，Tβ4-ASCs作为人工干细胞，在心肌梗死后可不断释放功能性外泌体，刺激侧支循环的形成，可为临床上心梗后的血运重建提供了一种可行的替代方法。