Drug Delivery and Biomimetic Approaches for Optimal Stem Cell Therapy

项目摘要 大量研究表明，成体干细胞主要通过旁分泌发挥其功能优势 影响，即，来自干细胞的分泌因子促进心脏再生并抑制纤维化， 炎症然而，两个主要的挑战仍然有效地提供干细胞因子受伤 心肌：1）注射的生长因子很快扩散，因此需要持续释放; 2）局部 注射有效，但需要开胸手术，全身注射安全，但不能充分 因此，需要靶向递送。为了克服这些挑战，我们设计了一个 血小板激发的纳米细胞（PINC），其具有包含干细胞因子的核心和血小板膜壳， 伤害捆绑核心由包封在可生物降解聚乙烯中的治疗性CSC分泌因子组成 （乳酸-共-乙醇酸）（PLGA）纳米颗粒用于持续释放。血小板膜与 PGE 2有望靶向心血管细胞，促进内源性修复 I/R损伤后通过PGE 2/EP受体信号传导。PINC是一种新型的仿生治疗纳米粒， 与天然干细胞相比，PINC提供了以下优点：（i）PINC足够小， 给药：纳米尺寸的PINC能够静脉内应用;与干细胞不同，PINC不太可能 PINC具有双重靶向作用：PINC上的血小板膜靶向损伤的血小板， （iii）PINC在储存期间是稳定的：不像PGE 2在心肌梗死中靶向受损的心肌细胞，而PGE 2在心肌梗死中靶向受损的心肌细胞。 作为真实的干细胞，PINCs可以容易地操作和冷冻保存，因为没有活的成分。 具体目标是：目标1。制造用PGE 2和CSC分泌蛋白质组功能化的PINC颗粒; PINC体外效价和细胞毒性; AIM 2.确定PINC的安全性、有效性和机制 在大鼠缺血再灌注（IR）损伤模型中的治疗; AIM 3.将研究结果转化为临床相关的 猪IR损伤模型。我们的研究将为创新和“现成”的治疗奠定基础， 分泌因子和靶向纳米药物，可以从供体干细胞系标准化， 异种心脏组织。我们的方法的无细胞性质更容易转化为临床。 虽然这个特殊的拨款申请的目标是心脏和心脏干细胞，我们的方法代表了一个 平台技术，可用于创建多种类型的合成干细胞和器官 用于修复各种其他器官的基质。

PROJECT SUMMARY Numerous studies indicate that adult stem cells exert their functional benefits mainly through paracrine effects, i.e., secreted factors from stem cells promote cardiac regeneration and inhibit fibrosis and inflammation. However, two major challenges remain to efficiently delivery stem cell factors to the injured myocardium: 1) injected growth factors are quickly diffused, therefore sustained release is needed; 2) local injection is effective but requires open chest procedure, systemic injection is safe but cannot get sufficient dosage to the heart, therefore targeted delivery is needed. To overcome those challenges, we designed a platelet-inspired nano-cell (PINC) that has a core containing stem cell factors and a platelet membrane shell for injury binding. The core consists of therapeutic CSC-secreted factors encapsulated in a biodegradable poly (lactic-co-glycolic acid) (PLGA) nanoparticle for sustained release. The platelet membrane is conjugated with PGE2 which is expected to have targetability to cardiovascular cells and facilitate the endogenous repair through PGE2/EP receptor signaling after I/R injury. As a novel biomimetic therapeutic nanoparticle, PINC offers the following advantages compared to natural stem cells: (i) PINC is small enough for systemic administration: the nano size of PINC enables intravenous application; unlike stem cells, PINCs are less likely to be blocked by the lungs; (ii) PINC has dual targeting ability: the platelet membrane on PINCs targets injured blood vessels while the PGE2 targets injured cardiomyocytes in MI; (iii) PINC is stable during storage: unlike real stem cells, PINCs can be readily manipulated and cryopreserved since there are no living components. The Specific Aims are: AIM 1. Fabricate PINC particles functionalized with PGE2 and CSC secretome; Test the in vitro potency and cytotoxicity of PINC; AIM 2. Determine the safety, efficacy, and mechanism of PINC therapy in a rat model of ischemia-reperfusion (IR) injury; AIM 3. Translate the findings into a clinically-relevant porcine model of IR injury. Our study will form the foundation for an innovative and “off the shelf” therapy based on secreted factors and targeted nanomedicine that can be standardized from donor stem cell lines and xenogeneic cardiac tissues. The cell-free nature of our approach is more readily translatable to the clinic. Although this particular grant application targets the heart and cardiac stem cells, our approach represents a platform technology that can be applied to the creation of multiple types of synthetic stem cell and organ matrices for the repair of various other organs.