Abstract
Urtica dioica agglutinin (UDA) is a carbohydrate-binding small monomeric protein isolated from stinging nettle rhizomes. It inhibits replication of a broad range of viruses, including coronaviruses, in multiple cell types, with appealing selectivity. In this work, we investigated the potential of UDA as a broad-spectrum antiviral agent against SARS-CoV-2. UDA potently blocks transduction of pseudotyped SARS-CoV-2 in A549.ACE2 + -TMPRSS2 cells, with IC 50 values ranging from 0.32 to 1.22 µM. Furthermore, UDA prevents viral replication of the early Wuhan-Hu-1 strain in Vero E6 cells (IC 50 = 225 nM), but also the replication of SARS-CoV-2 variants of concern, including Alpha, Beta and Gamma (IC 50 ranging from 115 to 171 nM). In addition, UDA exerts antiviral activity against the latest circulating Delta and Omicron variant in U87.ACE2 + cells (IC 50 values are 1.6 and 0.9 µM, respectively). Importantly, when tested in Air-Liquid Interface (ALI) primary lung epithelial cell cultures, UDA preserves antiviral activity against SARS-CoV-2 (20A.EU2 variant) in the nanomolar range. Surface plasmon resonance (SPR) studies demonstrated a concentration-dependent binding of UDA to the viral spike protein of SARS-CoV-2, suggesting interference of UDA with cell attachment or subsequent virus entry. Moreover, in additional mechanistic studies with cell-cell fusion assays, UDA inhibited SARS-CoV-2 spike protein-mediated membrane fusion. Finally, pseudotyped SARS-CoV-2 mutants with N-glycosylation deletions in the S2 subunit of the spike protein remained sensitive to the antiviral activity of UDA. In conclusion, our data establish UDA as a potent fusion inhibitor for the current variants of SARS-CoV-2.
Keywords: N-acetylglucosamine (GlcNAc); SARS-CoV-2; UDA; fusion inhibitor; lectin; spike protein.
【저자키워드】 SARS-CoV-2, spike protein., fusion inhibitor, lectin, UDA, N-acetylglucosamine (GlcNAc), 【초록키워드】 viruses, Coronaviruses, Antiviral, variant, variants of concern, Delta, antiviral activity, surface plasmon resonance, omicron, SPR, Spike protein, Replication, Protein, cells, viral replication, virus entry, Gamma, Deletion, Beta, membrane fusion, mutant, cell-cell fusion, Vero E6 cell, inhibitor, S2 subunit, interface, binding, SARS-CoV-2 spike, cell types, viral spike protein, N-glycosylation, circulating, cell cultures, pseudotyped SARS-CoV-2, Wuhan-Hu-1, variants of SARS-CoV-2, replication of SARS-CoV-2, block, Prevent, Cell, lung epithelial, tested, assays, subsequent, addition, investigated, remained, inhibit, inhibited, the spike protein, demonstrated, monomeric, Urtica, 【제목키워드】 SARS-CoV-2 variant, Protein, inhibitor,