Nanoplasmonics-enabled Quantitative Spatiotemporal Activity Mapping in Engineered

描述（由申请人提供）：分支形态发生是一个动态过程，用于构建各种器官，如肾脏、唾液腺和乳腺。为了研究分支形态发生，我们已经能够在三维（3D）工程组织阵列中重现体内组织结构，该阵列类似于体内分支乳腺的结构。工程化显示细胞的适当空间组织和组织结构的功能特性的分支组织结构可能潜在地用于替换有缺陷的组织。了解细胞分泌的信号如何指导分支形成对于工程化替代组织结构以及修复有缺陷的组织结构非常重要。基质金属蛋白酶（MMPs）以前已被确定为分支形态发生的关键介质，可能通过降解脂肪垫中的细胞外基质（ECM）。然而，这些蛋白酶的信号如何随时间向分支组织提供空间依赖的图案化信息仍不清楚。我假设分支模式是局部微环境中蛋白酶时空活性分布的结果，至少部分是这样。MMP还显示通过提供肿瘤细胞侵入ECM所必需的蛋白水解活性在肿瘤进展中起重要作用。这是合理的怀疑，图案信息不同的分支在功能正常的组织从恶性组织中，这些差异将反映在蛋白酶信号的时空活性曲线。为了回答这个问题，需要长期、真实的时间和定量测量局部微环境中分泌的蛋白酶的方法，但目前缺乏这种方法。纳米等离子体标尺由肽连接的贵金属纳米颗粒组成，其可用于通过随时间光学监测其光散射光谱来定量测量具有单分子灵敏度的蛋白酶活性。纳米等离子体统治者不会遭受光漂白或闪烁（即。波动的强度），因此，纳米等离子体标尺能够对分泌的蛋白酶进行长期和连续的光学测量。我建议采用nanoplasmonic统治者，能够长期的，真实的时间，和定量测量分泌的蛋白酶，了解分支过程和工程分支结构的目的。以下具体目标支持实现该目标：（1）使用先前表征的纳米等离子体标尺作为性能的正模型，验证纳米等离子体标尺适用于蛋白酶活性的长期、真实的时间和定量测量。(2)与恶性器官型培养物相比，确定非恶性器官型培养物中分支形成期间分泌蛋白酶的时空活性谱。(3)确定蛋白酶的调节是否改变时空活性谱和产生的分支模式。

DESCRIPTION (provided by applicant): Branching morphogenesis is a dynamic process used to construct a variety of organs, such as kidneys, salivary glands, and the mammary glands. To study branching morphogenesis, we have been able to recapitulate in vivo tissue structures in three-dimensional (3D) engineered tissue arrays that resemble the structure of the branching mammary glands in vivo. Engineering branched tissue structures that display appropriate spatial organization of cells and functional properties of a tissue structure may be potentially useful for replacing defective tissues. Understanding how secreted signals from cells direct branching formation is important for engineering replacement tissue structures as well as repairing defective tissue structures. Matrix metalloproteinases (MMPs) have been identified previously as key mediators of branching morphogenesis presumably by degrading the extracellular matrix (ECM) in the fat pad. However, it is still unclear how these proteinases' signals provide spatially dependent patterning information to the branching tissue over time. I hypothesize that branching patterns are the result, at least in part, of proteinases' spatiotemporal activity profiles in the local microenvironment. MMPs have also been shown to play an important role in tumor progression by providing the proteolytic activity necessary for tumor cells to invade the ECM. It is reasonable to suspect that patterning information differs for branching in functionally normal tissues from that in malignant tissues, and these differences would be reflected in the proteinase signals' spatiotemporal activity profiles. To answer this question, methods for long term, real time, and quantitative measurement of secreted proteinases in the local microenvironment are needed but are currently lacking. Nanoplasmonic rulers consist of peptide- linked noble metal nanoparticles which can be used to quantitatively measure proteinase activity with single molecule sensitivity by optically monitoring their light scattering spectra over time. Nanoplasmonic rulers do not suffer from photobleaching or blinking (ie. fluctuating intensities), and therefore, nanoplasmonic rulers are capable of long term and continuous optical measurements of secreted proteinases. I propose to employ nanoplasmonic rulers, capable of long term, real time, and quantitative measurements of secreted proteinases, for the purpose of understanding the branching process and engineering branched structures. The following specific aims support the attainment of this goal: (1) Verify nanoplasmonic rulers are appropriate for long term, real time and quantitative measurements of proteinase activity using previously characterized nanoplasmonic rulers as a positive model of performance. (2) Identify spatiotemporal activity profiles of secreted proteinases during branching formation in non-malignant as compared to malignant organotypic cultures. (3) Determine whether modulation of proteases modifies spatiotemporal activity profiles and resulting branching patterns.