Inorganic polyphosphates (polyPs) are linear polymers composed of repeated phosphate (PO₄³⁻) units linked together by multiple high-energy phosphoanhydride bonds. In addition to being a source of energy, polyPs have cytoprotective and antiviral activities. Here, we investigated the antiviral activities of long-chain polyPs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In molecular docking analyses, polyPs interacted with several conserved amino acid residues in angiotensin-converting enzyme 2 (ACE2), the host receptor that facilitates virus entry, and in viral RNA-dependent RNA polymerase (RdRp). ELISA and limited proteolysis assays using nano– LC-MS/MS mapped polyP120 binding to ACE2, and site-directed mutagenesis confirmed interactions between ACE2 and SARS-CoV-2 RdRp and identified the specific amino acid residues involved. PolyP120 enhanced the proteasomal degradation of both ACE2 and RdRp, thus impairing replication of the British B.1.1.7 SARS-CoV-2 variant. We thus tested polyPs for functional interactions with the virus in SARS-CoV-2–infected Vero E6 and Caco2 cells and in primary human nasal epithelial cells. Delivery of a nebulized form of polyP120 reduced the amounts of viral positive-sense genomic and subgenomic RNAs, of RNA transcripts encoding proinflammatory cytokines, and of viral structural proteins, thereby presenting SARS-CoV-2 infection in cells in vitro.

无机多磷酸盐 (polyPs) 是由重复磷酸盐 (PO ₄ ³⁻ ) 组成的线性聚合物) 通过多个高能磷酸酐键连接在一起的单元。除了作为能量来源之外，polyPs 还具有细胞保护和抗病毒活性。在这里，我们研究了长链息肉对严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 感染的抗病毒活性。在分子对接分析中，polyPs 与血管紧张素转换酶 2 (ACE2)（促进病毒进入的宿主受体）和病毒 RNA 依赖性 RNA 聚合酶 (RdRp) 中的几个保守氨基酸残基相互作用。ELISA 和使用 nano-LC-MS/MS 进行的有限蛋白水解测定绘制了 polyP120 与 ACE2 的结合，以及定点诱变证实了 ACE2 和 SARS-CoV-2 RdRp 之间的相互作用，并确定了所涉及的特定氨基酸残基。PolyP120 增强了 ACE2 和 RdRp 的蛋白酶体降解，从而削弱了英国 B.1.1.7 SARS-CoV-2 变体的复制。因此，我们在感染了 SARS-CoV-2 的 Vero E6 和 Caco2 细胞以及原代人鼻上皮细胞中测试了 polyP 与病毒的功能相互作用。雾化形式的 polyP120 的递送减少了病毒正义基因组和亚基因组 RNA、编码促炎细胞因子的 RNA 转录物和病毒结构蛋白的数量，从而在体外细胞中呈现 SARS-CoV-2 感染。