Pineapple Lectin AcmJRL Binds SARS-CoV-2 Spike Protein in a Carbohydrate-Dependent Fashion.

The highly glycosylated spike protein of SARS-CoV-2 is essential for infection and constitutes a prime target for antiviral agents and vaccines. The pineapple-derived jacalin-related lectin AcmJRL is present in the medication bromelain in significant quantities and has previously been described to bind mannosides. Here, we performed a large ligand screening of AcmJRL by glycan array analysis, quantified the interaction with carbohydrates and validated high-mannose glycans as preferred ligands. Because the SARS-CoV-2 spike protein was previously reported to carry a high proportion of high-mannose N-glycans, we tested the binding of AcmJRL to the recombinantly produced extraviral domain of spike protein. We could demonstrate that AcmJRL binds the spike protein with a low-micromolar KD in a carbohydrate-dependent fashion.

Ciprofloxacin-loaded lipid-core nanocapsules as mucus penetrating drug delivery system intended for the treatment of bacterial infections in cystic fibrosis.

Treatment of bacterial airway infections is essential for cystic fibrosis therapy. However, effectiveness of antibacterial treatment is limited as bacteria inside the mucus are protected from antibiotics and immune response. To overcome this biological barrier, ciprofloxacin was loaded into lipid-core nanocapsules (LNC) for high mucus permeability, sustained release and antibacterial activity. Ciprofloxacin-loaded LNC with a mean size of 180nm showed a by 50% increased drug permeation through mucus. In bacterial growth assays, the drug in the LNC had similar minimum inhibitory concentrations as the free drug in P. aeruginosa and S. aureus. Interestingly, formation of biofilm-like aggregates, which were observed for S. aureus treated with free ciprofloxacin, was avoided by exposure to LNC. With the combined advantages over the non-encapsulated drug, ciprofloxacin-loaded LNC represent a promising drug delivery system with the prospect of an improved antibiotic therapy in cystic fibrosis.