Probing the role of heparanase via in situ labeling

摘要 硫酸乙酰肝素蛋白聚糖（HSPG），是肝细胞外基质（ECM）的主要成分， 所有组织类型，参与ECM的结构完整性，并通过 与ECM组分和蛋白质配体如生长因子和趋化因子结合。 乙酰肝素酶，唯一已知的可以切割硫酸乙酰肝素（HS）侧链的酶， HSPGs调节许多细胞过程，包括ECM重塑和细胞内稳态。 与HS结合，并且它控制与HS连接的分子的生物利用度和活性。我们 假设乙酰肝素酶以程序化方式切割HS侧链-某些HS 裂解导致细胞播散，而其他特定HS结构的裂解负责 释放特定的信号分子，或HSPGs的稳态。我们的长期目标是 定义乙酰肝素酶在各种病理条件下的确切作用。目前的研究 专注于开发一套分子工具， 活细胞和动物模型中的乙酰肝素酶活性。这些结构上定义的探针 结合原位标记策略以保留乙酰肝素酶作用位点处的读出信号， 实现高空间分辨率和精度。我们将使用这些分子探针来测试我们的 在癌症模型中的假设，并研究乙酰肝素酶在结构上定义的作用， ECM重塑使用分子成像在体外和体内。 !

Abstract Heparan sulfate proteoglycans (HSPGs), major components in the extracellular matrix (ECM) of all tissue types, participate in structural integrity of ECM and regulate cellular signaling via binding with ECM components and protein ligands such as growth factors and chemokines. Heparanase, the only known enzyme that can cleave the heparan sulfate (HS) side chains of HSPGs, regulates many cellular processes including ECM remodeling and homeostasis of cell- associated HS, and it controls the bioavailability and activity of molecules attached to HS. We hypothesize that heparanase cleaves HS side chains in a programmed manner – certain HS cleavage leads to cell dissemination, while cleavage of other specific HS structures is in charge of release of specific signaling molecules, or homeostasis of HSPGs. Our long term goal is to define the precise role of heparanase in various pathological conditions. The current research focuses on the development of a set of molecular tools that can visualize spatiotemporal activities of heparanase in both live cells and animal models. These structurally defined probes incorporate in situ labeling strategy to retain the readout signals at site of heparanase action to achieve high spatial resolution and precision. We will use these molecular probes to test our hypothesis in cancer models, and to study the structurally defined role of heparanase during ECM remodeling using molecular imaging both in vitro and in vivo. !