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。 但控制它们的活性和选择性可能是具有挑战性的。GFS作为膜的配体- 控制信号级联的受体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内生长因子介导的信号活动的工具有 需要实现对这些分子的活性的控制，并改善它们的治疗特性。肝素 硫酸盐(HS)蛋白多糖(PG)虽然经常被忽视，但特别适合于这一目的，因为它们经常 在细胞表面作为GFS的辅助受体。通过促进GFS和GFS之间形成络合物 他们的受体，他们平衡相互竞争的信号通路，并调节细胞反应。而结构 而HS对细胞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更加通用和 更适合于治疗应用。这个项目建立了这样的工具，称为新PG嵌合体，它将 能够选择性地激活或抑制细胞内的生长因子信号活性。这将通过利用 HS系统诱变产生的重组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，性质- 针对GF结合特异性进行了优化，并与功能元件合并，以靶向细胞。膜靶向 将开发新的PG嵌合体，以促进GF与细胞表面受体的结合，并促进GF 信号活动(目标1)。溶酶体靶向的新PG嵌合体将被用来驱动细胞外GFS进入 细胞的降解，从而抑制信号活性(目标2)。这项研究的重点将是建立和 验证新的PG嵌合体作为信号的致动器由成纤维细胞生长因子家族的成员的PRO- 在细胞增殖和分化的背景下的蛋白质。然而，许多其他类别GFS需要单元格 表面HS的功能和新工具有望在许多不同方面得到广泛的应用 生物医学研究和基于生长因子的疗法。

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.