Cell membrane-targeting proteoglycan chimeras as selective growth factor signaling actuators

项目摘要 基于生长因子（GF）的疗法在组织工程、癌症治疗和再生方面具有巨大的前景。 但是控制它们的活性和选择性可能具有挑战性。GFs作为膜的配体- 受体控制信号级联，驱动基因表达和细胞功能，如增殖 和差异化。可以选择性地激活或抑制细胞中GF介导的信号传导活性的工具是 需要实现对这些分子的活性的控制并改善其治疗性质。乙酰肝素 硫酸化（HS）蛋白聚糖（PG）虽然经常被忽视，但特别适合于此目的，因为它们通常 在细胞表面作为GF的辅助受体。通过促进GF和 它们的受体，它们平衡竞争信号通路并调节细胞反应。虽然结构 并且HS在细胞上的活性可以在一定程度上通过其生物合成的基因工程来控制， 用于重塑细胞硫酸盐HS以获得GF结合特异性的化学工具将莫尔普遍， 更适合于治疗应用。该项目建立了这样的工具，称为neoPG嵌合体，将 能够选择性地激活或抑制细胞中的GF信号传导活性。这将通过利用 通过系统突变HS产生的重组HS多糖的GF结合选择性 实验室细胞系中的生物合成酶。重组HS多糖将被收获，特征- 其针对GF结合特异性进行化，并与用于靶向细胞的功能元件合并。膜靶向 将开发neoPG嵌合体以促进GF与细胞表面的受体结合，并促进GF 信号传导活性（Aim 1）。溶酶体靶向neoPG嵌合体将用于驱动细胞外GF进入细胞内。 细胞降解，从而抑制信号传导活性（目的2）。这项研究的重点将是建立和 验证neoPG嵌合体作为成纤维细胞生长因子家族成员的信号传导的致动器， 在细胞增殖和分化的背景下，然而，许多其他类别的GF需要细胞 表面HS的功能和新的工具，预计将找到广泛的应用在许多不同的方面， 生物医学研究和基于GF的疗法。

Project Summary Growth factor (GF)-based therapies hold great promise for tissue engineering, cancer treatment, and regenera- tive medicine but controlling their activity and selectivity can be challenging. GFs act as ligands for membrane- receptors controlling signaling cascades that drive gene expression and cellular functions, such as proliferation and differentiation. Tools that can selectively activate or suppress GF-mediated signaling activity in cells are needed to achieve control over the activity of these molecules and improve their therapeutic properties. Heparan sulfate (HS) proteoglycans (PGs), while often overlooked, are uniquely suited for this purpose, as they often serve as coreceptors for GFs at the cell surface. By promoting the formation of complexes between GFs and their receptors, they balance competing signaling pathways and regulate cellular responses. While the structure and activity of HS on cells can be controlled, to some extent, through genetic engineering of their biosynthesis, chemical tools for remodeling cell-sulfate HS to attain GF-binding specificity would be much mor general and better suited for therapeutic applications. This project establishes such tools, termed neoPG chimeras, that will be able to selectively activate or inhibit GF signaling activity in cells. This will be achieved by taking advantage of the GF-binding selectivities of recombinant HS polysaccharides produced through systematic mutation of HS biosynthetic enzymes in laboratory cell lines. The recombinant HS polysaccharides will be harvested, character- ized for GF binding specificity and merged with functional elements for targeting to the cells. Membrane targeting neoPG chimeras will be developed to promote GF association with receptors at the cell surface and promote GF signaling activity (Aim 1). Lysosome-targeting neoPG chimeras will be used to drive extracellular GFs into the cells for degradation, thus inhibiting signaling activity (Aim 2). The focus of this study will be on establishing and validating neoPG chimeras as actuators of signaling by members of the Fibroblast Growth Factor family of pro- teins in the context of cellular proliferation and differentiation. However, many other classes of GFs require cell surface HS for function and the new tools are expected to find broad application in many different aspects of biomedical research and GF-based therapies.