In a recent study published in the journal advanced scienceResearchers have developed molecularly imprinted nanoparticles (nanoMIPs) with broad-spectrum activity against deadly viruses.
Stady: Rational development of highly valence shield-linked glycan nanoparticles with broad-spectrum inhibition against deadly viruses including SARS-CoV-2 variants. Image credit: Kateryna Kon/Shutterstock
Viral infectious diseases pose a profound threat to humans. The recent outbreak of coronavirus disease 2019 (COVID-19) has severely threatened public health, economy and social development globally. Despite the development of multiple preventive and therapeutic strategies, rapidly changing viral antigen profiles present significant challenges, as evidenced by mutant variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Thus, broad-spectrum interferon inhibitors are highly warranted.
Glycosylation, the overall post-translational modification, plays several critical roles. Several viruses have evolved to use the host translation machinery to modify their proteins with ‘self’ glycans, resulting in highly glycosylated viral envelopes. These glycosylated proteins protect the immune surfaces with a dense envelope of host-derived glycans, thus facilitating immune escape.
Molecularly imprinted polymers (MIPs), also known as plastic/synthetic antibodies, are synthetic receptors with antibodies that mimic antibody binding through copolymerization in the presence of templates. Due to their ease of preparation, storage stability, and cost efficiency, MIPs show potential for various applications such as diagnostics, cancer treatment, virus recognition, and toxin neutralization. MIPs have been developed against viruses, but there is no broad spectrum activity.
Study and results
In this study, researchers in China developed glycan shield-binding nanoMIPs with broad and potent activity against viruses carrying high-mannose glycans. NanoMIPs were fabricated by microemulsion-oriented surface printing and coating (ROSIC) technology. Similarly, unimprinted nanoparticles (NIPs) were also synthesized using the same procedure without templates.
The resulting nanoMIPs had a well-defined spherical shape with a mean diameter of 39.5 nm. The specific uptake of mannose by nanoMIPs was significantly high. Of note, nanoMIPs had superior performance over some mannose binding lectins. NanoMIPs showed little/no binding activity for non-glycosylated proteins. Each nanoMIP was able to bind more than 50 high-mannose glycans.
The authors next studied the binding and kinetics of the nanoMIPs to proteins with high-mannose glycans using a biolayer interferometer. First, RNase B was used as a target protein, and the dissociation constant (KDr) was 1.3 x 10-6 M, improved by two to three orders of magnitude relative to K.Dr mannose. The letter KDr For SARS-CoV-2 S1 protein it was 5.3 x 10-7 In contrast, NIPs did not bind to RNase or SARS-CoV-2 S1.
Moreover, the researchers found that nanoMIPs bind to SARS-CoV-2 Untruthful It was enhanced by three orders of magnitude relative to the SARS-CoV-2 S1 protein, indicating that nanoMIPs can bind viruses with high smoothness. Next, the authors evaluated the competitive binding of nanoMIPs with angiotensin-converting enzyme 2 (ACE2) at pseudoviral protein and levels. At the protein level, binding of ACE2 to SARS-CoV-2 S1 was not observed even at high concentrations of ACE2 (up to 200 nM).
Illustration of virus inactivation by higher mannose nanoMIP.
At the pseudovirus level, ACE-2 binding (to pseudovirus) decreased with increasing nanoMIPs concentrations, with complete inhibition at 100 μg/mL. In a pseudovirus neutralization assay, nanoMIPs showed 90.2% inhibition of wild-type SARS-CoV-2 viral particles. Likewise, high inhibition effectiveness observed with SARS-CoV-2 pseudoviruses harboring N439K, N501Y, D614G, or Δ69-70 mutations and SARS-CoV-2 Delta and Omicron variants.
The nanoMIPs inhibited 95.5% of Lasso virus pseudomonas and 97.2% of HIV pseudomonas viruses, supporting the broad-spectrum activity of nanoMIPs against Lasso virus, HIV, SARS-CoV-2 and its mutant variants. SARS-CoV-2 pseudoviruses treated with nanoMIPs clustered in clusters, with a few pseudoviruses outside the clusters. Furthermore, fluorescently labeled SARS-CoV-2 pseudoviruses were pretreated with nanoMIPs and incubated with host cells.
Strong inactivation of live viruses. a, b) Loading of native SARS-CoV-2 virus (wild type and delta) RNA at 3 days post infection from Vero cells treated with different concentrations of nanoMIP. Mean ± SD, n = 3. Cytopathy effect (CPE) images of Vero cells treated with nanoMIP (800 μg ml)-1), NIP (800 μg ml-1) and MBL (10 μg ml-1) under live SARS-CoV-2 infection for 3 days.
Fluorescent images showed that nanoMIPs could efficiently bind viruses, and aggregate around the host cell membrane. The nanoMIP-induced pseudomonas virus aggregates were sub-micron to micron in size. Further experiments revealed that nanoMIP-induced pseudomonas virus aggregates could enhance phagocytosis, activate innate immunity, and facilitate virus inhibition.
Finally, the researchers evaluated the efficacy of nanoMIPs for neutralizing the authentic SARS-CoV-2 wild type and the delta variant. NanoMIPs suppressed infection of Vero cells with native SARS-CoV-2 (wild type and delta variant). The viral RNA load decreased with increasing nanoMIP concentrations of both the wild type and the delta variant. There was little/no cytokinesis effect (CPE) with nanoMIP treatment in contrast to CPE evident with treatment with NIPs or mannose-binding lectins.
In summary, the researchers have developed highly specific glycan shield-bound synthetic antibodies of high potency and broadening against several viruses. The high binding affinity, steric hindrance, and rigid structure of nanoMIPs effectively prevented interactions between host cells and viral particles. NanoMIPs induced viral accumulation by simultaneous binding to multiple viruses, preventing viral entry into host cells and facilitating phagocytosis.
Due to their blocking and cross-linking capabilities, supervalent nanoMIPs presented a unique strategy of potent broad-spectrum inhibitory activity against various viruses, switching from antigens/episodes to glycan shields of viruses, thus circumventing challenges associated with viral diversity and mutagenesis.