Magnetic Steering and Longitudinal Visualization of Stem Cells for Trabecular Meshwork Therapy in Glaucoma

项目概要/摘要 青光眼是导致失明的主要原因，目前的治疗方法还不够。青光眼的一个主要危险因素， 唯一可治疗的危险因素是眼内压（IOP）升高。目前的降眼压疗法也失败了 经常发生，因此人们对新颖的 IOP 控制策略仍然抱有极大的兴趣。小梁网 (TM) 是决定 IOP 的关键组织，它减少了青光眼中的细胞结构，这导致许多研究小组 研究基于干细胞的 TM 疗法。这种疗法的一个障碍是细胞递送：目前的方法 细胞对TM的递送效率和特异性较低，不能将细胞递送至TM的所有部位。 这里提出了一种将干细胞“引导”至 TM 的新颖技术解决方案，该解决方案还可以 用于可视化干细胞递送并监测干细胞凋亡。该方法将在多个方面进行测试 高眼压症模型。关键技术是超顺磁性和光敏纳米颗粒。 它们的超顺磁特性意味着吸收这些纳米粒子的细胞可以快速 通过放置在角膜缘的磁铁将其引导至 TM。它们的光敏性意味着细胞可以通过以下方式可视化 活体眼睛中的超声/光声成像。这些纳米粒子的功能将进一步 通过使用活性 caspase-3 的光敏标记来监测干细胞凋亡。我们的整体 目标是验证这些技术作为监测和指导干细胞的安全有效的方法 细胞到TM，从而恢复青光眼患者的眼内压（IOP）稳态。 基于我们重要的初步数据，提出了实现这一长期目标的三个具体目标。瞄准目标 1，将合成并表征用于监测细胞凋亡的新型 caspase-3 敏感报告基因，以及 用于将干细胞引导至 TM 的磁铁将得到优化。在目标 2 中，一种能够对标记物进行成像的仪器 全眼干细胞，包括干细胞分布和凋亡的纵向监测，将被 开发的。在目标 3 中，干细胞将被输送到两个青光眼模型的 TM 中，并恢复它们的能力 将评估眼压稳态。超声/光声成像监测干细胞输送的能力 对TM和干细胞凋亡的影响也将得到验证；和间充质干细胞（MSC）将进行比较 分化诱导多能干细胞（iPSC-TM）在恢复眼压稳态方面的功效。这个 该项目具有高度创新性：它是第一项将干细胞引导和可视化作为眼部治疗的一部分的研究 高血压。这也是首次比较 MSC 与 iPSC-TM 治疗高眼压症的疗效。 正如我们强有力的初步数据所表明的那样，我们期望发现干细胞可以有效且有效地 通过放置在角膜缘的简单磁铁选择性地引导至 TM，时间仅需 15 分钟；并且它会 能够准确监测干细胞在眼睛中的位置以及干细胞随时间的凋亡。此外， 正如在 2 个青光眼模型中所测试的那样，我们预计以这种方式引导的干细胞将改善 TM 功能。

Project Summary/Abstract Glaucoma is a major cause of blindness and current treatments are insufficient. A major risk factor for glaucoma, and the only treatable risk factor, is elevated intraocular pressure (IOP). Current IOP-lowering therapies fail too often, and thus there continues to be great interest in novel IOP control strategies. The trabecular meshwork (TM), the key tissue determining IOP, has reduced cellularity in glaucoma, which has led a number of groups to study stem cell-based therapies for the TM. An obstacle to such therapies is cell delivery: current approaches have low cell delivery efficiency and specificity for the TM, and cannot deliver cells to all parts of the TM. Here a novel technological solution for “steering” stem cells to the TM is proposed, which can be additionally used to visualize stem cell delivery and to monitor stem cell apoptosis. This approach will be tested in several models of ocular hypertension. The key technology is superparamagnetic and photosensitive nanoparticles. Their superparamagnetic properties mean that cells which have taken up these nanoparticles can be rapidly steered to the TM by a magnet placed at the limbus. Their photosensitivity means that cells can be visualized by ultrasound/photoacoustic imaging in the living eye. The functionality of these nanoparticles will be further enhanced by using a photosensitive marker of active caspase-3 to monitor stem cell apoptosis. Our overall objective is to validate these technologies as a safe and effective approach for monitoring and steering of stem cells to the TM, thereby restoring intraocular pressure (IOP) homeostasis in glaucoma patients. Three specific aims towards this long-term goal are proposed, building on our significant preliminary data. In aim 1, a novel caspase-3-sensitive reporter for monitoring apoptosis will be synthesized and characterized, and magnets for steering stem cells to the TM will be optimized. In aim 2, an instrument capable of imaging of labeled stem cells in whole eyes, including longitudinal monitoring of stem cell distribution and apoptosis, will be developed. In aim 3, stem cells will be delivered to the TM in two glaucoma models, and their ability to restore IOP homeostasis will be evaluated. The ability of ultrasound/photoacoustic imaging to monitor stem cell delivery to the TM and stem cell apoptosis will also be validated; and mesenchymal stem cells (MSCs) will be compared to differentiated induced pluripotent stem cells (iPSC-TMs) for their efficacy in restoring IOP homeostasis. This project is highly innovative: it the first study to steer and visualize stem cells as part of a treatment for ocular hypertension. It is also the first to compare the efficacy of MSCs vs. iPSC-TMs for treating ocular hypertension. We expect, as suggested by our strong preliminary data, to discover that stem cells can be efficiently and selectively steered to the TM by a simple magnet placed at the limbus for as little as 15 minutes; and that it will be possible to accurately monitor the location of stem cells in the eye and stem cell apoptosis over time. Further, we expect that TM function will be improved by stem cells steered in this way, as tested in 2 glaucoma models.