细胞衍生的生物矿化囊泡在急性肺损伤治疗中的研究

Acute lung injury (ALI) is a life-threatening disease caused by microbe infection, sepsis, trauma, ischemia or reperfusion, which often results in hyoxemia and acute severe respiratory failure with fast process and high mortality. Given the complexity of the disease and limitations of existing drugs, single modality is insufficient for ALI treatment. In this project, we will develop a novel kind of biomineralized extracellular vesicles (EVs) which can target inflammatory microenvironment based on the pathophysiology of ALI. Mesenchymal stem cells derived extracellular vesicles (MSC-EVs) are first employed, within which biomineralization reaction is carried out to realize efficient and stable package of dexamethasone. The immunosuppressive cytokine interleukine-10 is further trapped on the vesicles based on the property of vesicular membrane. Then the EVs are modified with targeting molecules. Taking advantage of the innate homing capacity of MSC-EVs and highly expressed Siglec-E receptors on the surface of inflammatory cells, the formulated biomineralized EVs will promote the accumulation of drugs in inflammatory microenvironment and target to inflammatory cells. In combination with temporal drug release and reparative property of MSC-EVs, the system can effectively regulate the activity of inflammatory cells and secretion of inflammatory cytokines, reduce oxidative stress, and repair damaged endothelial cells to control or even eliminate inflammation. It will exploit the inflammation targeting ability, reparative property and synergistic anti-inflammatory effect as well as co-delivery of small molecule and biomacromolecule of biomineralized EVs. It provides a promising strategy to realize the breakthrough on current clinical drug treatment dilemma of ALI.

急性肺损伤是临床常见危重病症，其发病机制复杂、疾病进程快、病死率高。现有治疗药物选择性差、副作用大，且单一用药难以应对疾病的复杂性。本项目基于急性肺损伤的病理生理学特点，拟构建具有炎症微环境靶向特性的生物矿化囊泡。该体系以干细胞衍生的细胞外囊泡为载体，利用囊泡内生物矿化反应实现抗炎药物地塞米松的高效稳定负载，进一步结合囊泡膜表面特性负载免疫细胞因子IL-10，并进行靶向修饰。通过囊泡固有的归巢效应和炎症细胞表面高表达的Siglec-E受体，靶向递送药物至炎症微环境和炎症细胞；结合药物可控释放和囊泡修复特性，发挥多通路协同作用，有效调控炎症细胞活性及炎症因子水平，减少氧化应激，修复受损内皮细胞，达到控制和消除炎症的目的。相关研究将探索生物矿化囊泡炎症靶向能力、修复特性、小分子与生物大分子药物共递送及协同抗炎效应，以期为急性肺损伤提供有效的药物治疗新策略，改善现阶段临床药物治疗困境。

急性肺损伤(ALI)是以肺部急性炎症、肺上皮和内皮损伤以及肺水肿为特征的临床危重症，其致死率仍高达40%，尚无特效药物。当前用于ALI的治疗药物存在选择性差、副作用大，且单一用药难以起效等问题。如何针对ALI病理及生理学特性，实现抗炎药物向肺部炎症部位的靶向递送与可控释放，并有效调节肺部炎症微环境，是解决ALI药物治疗困境面临的主要难题。本项目从临床迫切需求出发，基于ALI肺血管通透性增加和炎症微环境特征，发展了新型细胞衍生的囊泡载药系统。首先，利用反相微乳法构建矿化纳米粒，经磷脂转相和细胞囊泡包被，制备了可负载多个小矿化纳米粒团簇的囊泡。该杂化囊泡可发挥矿化纳米粒对抗炎药物的高效包载作用，并携带囊泡膜表面丰富的功能性生物配体。经炎症靶向和免疫调节特性考察，最终选择了具良好抗炎作用的M2巨噬细胞囊泡。评价了细胞表面膜蛋白和磷脂保留情况、膜蛋白定位及体内外生物学效应。研究发现，生物矿化囊泡显示出良好的炎症肺部趋向性，注射48 h后，其肺/肝比相比于正常小鼠增加约5.5倍。为进一步提高对肺部炎症的靶向能力，基于M2巨噬细胞囊泡与抗炎药物脂质体构建了杂化仿生囊泡，其体内肺/肝比可高达14.93，相比于游离的膜囊泡增加了约52倍，更有效提高了肺部药物分布。该仿生囊泡可被吞噬细胞（巨噬细胞和中性粒细胞）高效摄取，有效调节巨噬细胞极化，抑制炎性巨噬细胞分泌NO和炎症细胞因子。在ALI小鼠模型中，载药囊泡继承了M2巨噬细胞免疫调节特性，与抗炎药物发挥协同作用，减少肺泡灌洗液中炎症细胞浸润，缓解肺部炎症因子风暴，同时抑制髓过氧化物酶和活性氧等促炎介质，减轻对肺血管屏障损伤，发挥对肺脏的保护作用。本研究结合具有抗炎作用的细胞囊泡和载药纳米粒的双重优势，实现了对肺部炎症微环境的高效递送和多重干预，深入探讨了其介导的抗炎机制，为克服当下ALI临床药物治疗的局限性，并推动纳米药物的临床转化应用提供了新的研究思路和递送策略。相关研究成果发表于ACS Nano、APSB等杂志。

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