. Data are expressed as a percentage of ACE2 binding relative to S1 WT (n=12 per group). Results are shown as mean ± SEM and were analyzed with Tukey’s multiple comparison test. ***p-value<0.001 vs S1 WT; °°°p-value<0.001 vs S1 N61D. " width="100%" height="100%">
Journal: Frontiers in Immunology
Article Title: Acetylsalicylic acid disrupts SARS-CoV-2 spike protein glycosylation and selectively impairs binding to ACE2
doi: 10.3389/fimmu.2025.1706997
Figure Lengend Snippet: Structural mapping and functional relevance of glycosylation sites on SARS-CoV-2 S1 protein upon ASA treatment. (A) Schematic representation of the SARS-CoV-2 Spike S1 protein, comprising a signal peptide (SP, aa 1–13), the N-terminal domain (NTD; aa 14–305) a short interdomain linker (IL, aa 306–318), the receptor binding domain (RBD, aa 319–541), and subdomain 1 (SD1, aa 542–591) and subdomain 2 (SD2, aa 592–686). Glycoproteomic profiling revealed 8 N-linked and 25 O-linked glycosylation sites across different domains of S1. Treatment of the S1 with ASA 20 mg/L selectively removed N-glycosylation at residue N61 and O-glycosylation at residues T250, S325, S494, T572, and T645 (indicated in red). (B) Representative Western blot and quantification of S1 acetylation after overnight incubation in PBS or with increasing concentrations of ASA (ASA 5 mg/L, ASA 20 mg/L, and ASA 50 mg/L). Acetyl-lysine levels were detected using a rabbit anti-acetyl-lysine antibody, while a mouse anti-RBD antibody was used as loading control for normalization. Results are shown as mean ± SEM and were analyzed with Tukey’s multiple comparison test. *p-value<0.05, and **p-value<0.01 vs PBS. (C) Western blot analysis of wild-type S1 (S1 WT), mutant S1 N61D, and the double mutant S1 N61D/S325A, confirming successful expression and comparable molecular weight of the produced recombinant proteins. (D) Quantification of ACE2 binding to recombinant S1 proteins using the ELISA-based functional assay described in Figure 1B . Data are expressed as a percentage of ACE2 binding relative to S1 WT (n=12 per group). Results are shown as mean ± SEM and were analyzed with Tukey’s multiple comparison test. ***p-value<0.001 vs S1 WT; °°°p-value<0.001 vs S1 N61D.
Article Snippet: At confluence, cells were exposed to control medium alone (EMEM supplemented with 2% FBS, 1X P/S) or with S1 at a concentration of 10 nM, 20 nM, and 50 nM in the presence of anti-ACE2 functional blocking antibody (α-ACE2, 2 μg/ml, Adipogen, AG-20A-0037PF) or the corresponding normal mouse IgG (IRR; Santa Cruz, sc-2025).
Techniques: Functional Assay, Glycoproteomics, Binding Assay, Residue, Western Blot, Incubation, Control, Comparison, Mutagenesis, Expressing, Molecular Weight, Produced, Recombinant, Enzyme-linked Immunosorbent Assay, Significance Assay