Long-chain polyphosphates impair SARS-CoV-2 infection and replication

Ferrucci, Veronica; Kong, Dae-Young; Asadzadeh, Fatemeh; Marrone, Laura; Boccia, Angelo; Siciliano, Roberto; Criscuolo, Giuseppina; Anastasio, Camilla; Quarantelli, Fabrizio; Comegna, Marika; Pisano, Ida; Passariello, Margherita; Iacobucci, Ilaria; Monica, Rosa Della; Izzo, Barbara; Cerino, Pellegrino; Fusco, Giovanna; Viscardi, Maurizio; Brandi, Sergio; Pierri, Bianca Maria; Borriello, Giorgia; Tiberio, Claudia; Atripaldi, Luigi; Bianchi, Martina; Paolella, Giovanni; Capoluongo, Ettore; Castaldo, Giuseppe; Chiariotti, Lorenzo; Monti, Maria; De Lorenzo, Claudia; Yun, Kyong-Seop; Pascarella, Stefano; Cheong, Jae-Ho; Kim, Hong-Yeoul; Zollo, Massimo

Inorganic polyphosphates (polyPs) are linear polymers composed of repeated phosphate (PO(4)(3−)) 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.