Department of Pathology and Laboratory Medicine, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
Centre for Blood Research, Life Science Institute, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
Mol Pharm. 2022 Jun 6;19(6):1853-1865. doi: 10.1021/acs.molpharmaceut.1c00934. Epub 2022 May 2.
The polyanion, inorganic polyphosphate (polyP), is a procoagulant molecule which has become a promising therapeutic target in the development of antithrombotics. Neutralizing polyP's prothrombotic activity using polycationic inhibitors is one of the viable strategies to design new polyP inhibitors. However, in this approach, a fine balance between the electrostatic interaction of polyP and the inhibitor is needed. Any unprotected polycations are known to interact with negatively charged blood components, potentially resulting in platelet activation, cellular toxicity, and bleeding. Thus, designing potent polycationic polyP inhibitors with good biocompatibility is a major challenge. Building on our previous research on universal heparin reversal agent (UHRA), we report polyP inhibitors with a modified steric shield design. The molecular weight, number of cationic binding groups, and the length of the polyethylene glycol (PEG) chains were varied to arrive at the desired inhibitor. We studied two different PEG lengths (PEG-750 versus PEG-350) on the polyglycerol scaffold and investigated their influence on biocompatibility and polyP neutralization activity. The polyP inhibitor with PEG-750 brush layer, PEG UHRA-10, showed superior biocompatibility compared to its PEG-350 analogs by a number of measured parameters without losing its neutralization activity. An increase in cationic binding groups (25 groups in PEG UHRA-8 and 32 in PEG UHRA-10 [HC]) did not alter the neutralization activity, which suggested that the PEG-750 shield layer provides significant protection of cationic binding groups and thus helps to minimize unwanted nonspecific interactions. Furthermore, these modified polyP inhibitors are highly biocompatible compared to conventional polycations that have been previously used as polyP inhibitors (e.g., PAMAM dendrimers and polyethylenimine). Through this study, we demonstrated the importance of the design of steric shield toward highly biocompatible polyP inhibitors. This approach can be exploited in the design of highly biocompatible macromolecular inhibitors.
多阴离子，无机多磷酸盐（polyP），是一种促凝分子，已成为抗血栓形成药物开发的有前途的治疗靶点。使用聚阳离子抑制剂中和 polyP 的促血栓形成活性是设计新的 polyP 抑制剂的可行策略之一。然而，在这种方法中，需要在 polyP 和抑制剂之间的静电相互作用之间取得良好的平衡。众所周知，任何未受保护的聚阳离子都会与带负电荷的血液成分相互作用，可能导致血小板活化、细胞毒性和出血。因此，设计具有良好生物相容性的有效聚阳离子 polyP 抑制剂是一个主要挑战。基于我们之前对通用肝素逆转剂（UHRA）的研究，我们报告了具有改进的空间位阻设计的 polyP 抑制剂。改变了分子量、阳离子结合基团的数量和聚乙二醇（PEG）链的长度，以获得所需的抑制剂。我们在聚甘油骨架上研究了两种不同的 PEG 长度（PEG-750 与 PEG-350），并研究了它们对生物相容性和 polyP 中和活性的影响。PEG-750 刷层的 polyP 抑制剂 PEG UHRA-10 与 PEG-350 类似物相比，通过多种测量参数显示出更好的生物相容性，而不会失去其中和活性。增加阳离子结合基团（PEG UHRA-8 中有 25 个，PEG UHRA-10 [HC]中有 32 个）不会改变中和活性，这表明 PEG-750 屏蔽层为阳离子结合基团提供了显著的保护，从而有助于最小化不必要的非特异性相互作用。此外，与之前用作 polyP 抑制剂的常规聚阳离子（例如 PAMAM 树枝状大分子和聚乙烯亚胺）相比，这些改性的 polyP 抑制剂具有更高的生物相容性。通过这项研究，我们证明了针对高度生物相容的 polyP 抑制剂的空间位阻设计的重要性。这种方法可用于设计高度生物相容的大分子抑制剂。
