Antiviral activity of marine sulfated glycans against pathogenic human coronaviruses

Electrochemical Immunoassay Platform for Human Monkeypox Virus Detection

In this study, we reported a selective impedimetric biosensor for the detection of A29 which is the target protein of the monkeypox virus (MPXV). The working principle of the biosensor relies on the interaction mechanism between A29, which is an internal membrane protein of MPXV, and the heparan sulfate receptor. For this purpose, after immobilizing heparan sulfate onto the gold screen-printed electrode surface, its interaction with A29 protein was monitored using electrochemical impedance spectroscopy. After the optimization of experimental parameters, the analytical characteristics of the developed MPVX immunosensor were examined. The developed immunosensor exhibited a linear detection range between 2.0 and 50 ng mL-1, with a detection limit of 2.08 ng mL-1 and a quantification limit of 6.28 ng mL-1. Furthermore, a relative standard deviation value of 2.82% was determined for 25 ng mL-1. Apart from that, sample application studies were also performed with the standard addition of A29 protein to 1:10 diluted real serum samples that were taken from healthy individuals, and very good recovery values were obtained.

Marine sulfated glycans inhibit the interaction of heparin with S-protein of SARS-CoV-2 Omicron XBB variant

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a worldwide COVID-19 pandemic, leading to 6.8 million deaths. Numerous variants have emerged since its outbreak, resulting in its significantly enhanced ability to spread among humans. As with many other viruses, SARS‑CoV‑2 utilizes heparan sulfate (HS) glycosaminoglycan (GAG) on the surface of host cells to facilitate viral attachment and initiate cellular entry through the ACE2 receptor. Therefore, interfering with virion-HS interactions represents a promising target to develop broad-spectrum antiviral therapeutics. Sulfated glycans derived from marine organisms have been proven to be exceptional reservoirs of naturally existing HS mimetics, which exhibit remarkable therapeutic properties encompassing antiviral/microbial, antitumor, anticoagulant, and anti-inflammatory activities. In the current study, the interactions between the receptor-binding domain (RBD) of S-protein of SARS-CoV-2 (both WT and XBB.1.5 variants) and heparin were applied to assess the inhibitory activity of 10 marine-sourced glycans including three sulfated fucans, three fucosylated chondroitin sulfates and two fucoidans derived from sea cucumbers, sea urchin and seaweed Saccharina japonica, respectively. The inhibitory activity of these marine derived sulfated glycans on the interactions between RBD of S-protein and heparin was evaluated using Surface Plasmon Resonance (SPR). The RBDs of S-proteins from both Omicrion XBB.1.5 and wild-type (WT) were found to bind to heparin, which is a highly sulfated form of HS. All the tested marine-sourced sulfated glycans exhibited strong inhibition of WT and XBB.1.5 S-protein binding to heparin. We believe the study on the molecular interactions between S-proteins and host cell glycosaminoglycans provides valuable insight for the development of marine-sourced, glycan-based inhibitors as potential anti-SARS-CoV-2 agents.

Synthesis and ab initio conformational investigation of a series of model sulfated α-L-iduronopyranosides

Due to the all-axial orientation of the OH-groups in the 1C4 chair conformation considered standard for L-hexapyranosides, including l-iduronopyranoside - a component of many biologically and medically significant sulfated glycans, these monosaccharides can be anticipated to display unusual conformations upon the introduction of bulky and charged substituents. Herein we describe the synthesis of a series of iduronopyranoside derivatives with varying sulfation patterns, which were studied computationally using the DLPNO-MP2 approach and by means of analyzing their chemical shifts to ascertain the effects sulfation has on the conformation of the iduronopyranoside ring.

Sulfated Glycans Inhibit the Interaction of MERS-CoV Receptor Binding Domain with Heparin

Middle East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic virus with high contagion and mortality rates. Heparan sulfate proteoglycans (HSPGs) are ubiquitously expressed on the surface of mammalian cells. Owing to its high negatively charged property, heparan sulfate (HS) on the surface of host cells is used by many viruses as cofactor to facilitate viral attachment and initiate cellular entry. Therefore, inhibition of the interaction between viruses and HS could be a promising target to inhibit viral infection. In the current study, the interaction between the receptor-binding domain (RBD) of MERS-CoV and heparin was exploited to assess the inhibitory activity of various sulfated glycans such as glycosaminoglycans, marine-sourced glycans (sulfated fucans, fucosylated chondroitin sulfates, fucoidans, and rhamnan sulfate), pentosan polysulfate, and mucopolysaccharide using Surface Plasmon Resonance. We believe this study provides valuable insights for the development of sulfated glycan-based inhibitors as potential antiviral agents.

Inhibition of adenovirus transport from the endosome to the cell nucleus by rotenone

Regardless of the clinical impact of human adenovirus (HAdV) infections in the healthy population and its high morbidity in immunosuppressed patients, a specific treatment is still not yet available. In this study, we screened the CM1407 COST Action's chemical library, comprising 1,233 natural products to identify compounds that restrict HAdV infection. Among them, we identified rotenolone, a compound that significantly inhibited HAdV infection. Next, we selected four isoflavonoid-type compounds (e.g., rotenone, deguelin, millettone, and tephrosin), namely rotenoids, structurally related to rotenolone in order to evaluate and characterized in vitro their antiviral activities against HAdV and human cytomegalovirus (HCMV). Their IC50 values for HAdV ranged from 0.0039 µM for rotenone to 0.07 µM for tephrosin, with selective indices ranging from 164.1 for rotenone to 2,429.3 for deguelin. In addition, the inhibition of HCMV replication ranged from 50% to 92.1% at twice the IC50 concentrations obtained in the plaque assay for each compound against HAdV. Our results indicated that the mechanisms of action of rotenolone, deguelin, and tephrosin involve the late stages of the HAdV replication cycle. However, the antiviral mechanism of action of rotenone appears to involve the alteration of the microtubular polymerization, which prevents HAdV particles from reaching the nuclear membrane of the cell. These isoflavonoid-type compounds exert high antiviral activity against HAdV at nanomolar concentrations, and can be considered strong hit candidates for the development of a new class of broad-spectrum antiviral drugs.