Tracking stem cells in engineered tissue and organs in vivo and in real time

描述(由申请人提供)： 为了响应PAR-06-504“组织工程和再生医学的使能技术”，我们提出了一种使能技术，通过体内和实时的非破坏性和非侵入性成像来跟踪带有生物共轭量子点(QD)的干细胞。与发育生物学类似，组织再生中的一个常见挑战是跟踪实时发育的细胞和组织。我们的初步数据表明，生物标记的量子点在几代人间充质干细胞(HMSCs)的增殖以及向软骨细胞和成骨细胞的分化过程中是安全的。我们还表明，通过SCID小鼠尾静脉注射的QD标记的hMSCs可以通过全身成像系统进行活体和实时跟踪。此外，我们能够实时跟踪体内皮下注射的多路QD标记的hMSCs。这些发现导致了我们的总体假设，即干细胞系统地运送回家局部缺陷并参与缺陷修复，这是以前很难研究的，因为缺乏体内和实时的细胞跟踪模式。这项建议的总体目标是确定体内和实时标记和跟踪间充质干细胞的有效性，并提高我们对不同细胞群在组织缺损修复中的相对贡献的理解。我们的长期目标是将QD标记应用于细胞跟踪，作为修复其他组织(如心脏、神经元和胰腺)以及其他肌肉骨骼组织(如骨-韧带界面、肌肉-肌腱连接等)的平台技术。 公共卫生相关声明(由申请者提供)：该项目有可能展示一种标记干细胞并实时跟踪体内再生组织发育的可行方法。它还有可能有助于我们理解工程化骨软骨界面，这在关节炎关节的生物工程化置换中具有关键价值。

DESCRIPTION (provided by applicant): In response to PAR-06-504 "Enabling Technologies for Tissue Engineering and Regenerative Medicine," we present an enabling technology of tracking stem cells with bioconjugated quantum dots (QDs) by non-destructive and non- invasive imaging, both in vivo and in real time. A common challenge in tissue regeneration, similar to developmental biology, is the tracking of cells and tissues that are developing in real time. Our preliminary data demonstrate that bioconjugated QDs are safe to label human mesenchymal stem cells (hMSCs) during proliferation for several passages, as well as differentiation into chondrocytes and osteoblasts. We also show that QD-labeled hMSCs, injected via the tail vein of SCID mice, can be tracked in vivo and in real-time by a whole body imager system. Furthermore, we were able to track multiplexing QD- labeled hMSCs injected subcutaneously in vivo and in real time. Theses findings lead to our overall hypothesis that stem cells delivered systemically home to local defects and participate in defect healing, which has been difficult to study previously due to the lack of in vivo and real time cell tracking modalities. The overall goal of this proposal is to determine the efficacy of QD labeling and tracking of MSCs in vivo and in real time, and to improve our understanding of the relative contribution of different cell populations to the healing of tissue defect. Our long-term goal is to apply QD labeling for cell tracking as a platform technology for the healing of other tissues such as cardiac, neuronal, and pancreatic, as well as other musculoskeletal tissues such as bone-ligament interface, muscle-tendon junction, etc. Public Health Relevance Statement (provided by applicant): This project has the potential to demonstrate a viable method for labeling stem cells and tracking the development of regenerating tissue in vivo and in real time. It also has a potential to contribute to our understanding of the engineered osteochondral interface that is of critical value in bioengineered replacement of arthritic joints.