Sulfonated Nanomaterials with Broad-Spectrum Antiviral Activity Extending beyond Heparan Sulfate-Dependent Viruses

Viral infections are among the main causes of death worldwide, and we lack antivirals for the majority of viruses. Heparin-like sulfated or sulfonated compounds have been known for decades for their ability to prevent infection by heparan sulfate proteoglycan (HSPG)-dependent viruses but only in a reversible way. We have previously shown that gold nanoparticles and beta-cyclodextrins coated with mercapto-undecane sulfonic acid (MUS) inhibit HSPG-dependent viruses irreversibly while retaining the low-toxicity profile of most heparin-like compounds. In this work, we show that, in stark contrast to heparin, these compounds also inhibit different strains of influenza virus and vesicular stomatitis virus (VSV), which do not bind HSPG. The antiviral action is virucidal and irreversible for influenza A virus (H1N1), while for VSV, there is a reversible inhibition of viral attachment to the cell. These results further broaden the spectrum of activity of MUS-coated gold nanoparticles and beta-cyclodextrins.

Virucidal nanomaterials against influenza

Özgün Kocabiyik

Influenza affects millions of people in all parts of the world. The fact that influenza virus can spread through air increases the chance of influenza outbreaks. There are 3 to 5 million severe cases of influenza resulting in 290,000 to 650,000 deaths every year. Not as common as outbreaks, but in the 20th century four influenza pandemics appeared: Spanish influenza (1918, 50 million deaths), Asian influenza (1957, 2 million deaths), Hong Kong influenza (1968, 1 million deaths) and swine influenza pandemic (2009, 150,000 to 500,000 deaths). World health organization (WHO) emphasizes that influenza is the only pathogen that has a reasonable chance of causing a new pandemic in the near future. It is unlikely that current influenza vaccines and therapeutics will be sufficient to prevent a coming pandemic. Presented within this thesis is a novel approach to irreversibly inhibit influenza virus with non-toxic and highly effective nanomaterials. These nanomaterials are designed so to bear glycan end-groups that bind to the influenza virus with high-affinity. Their design is such that binding determines a chain of events that leads to the irreversible loss of viral infectivity (i.e. virucidal mechanism). There are two key elements in the design of these materials. The first is the correct glycan sequence, terminating with sialic acid, needed to bind with high affinity to the influenza virus attachment ligand that is hemagglutinin. The second is a certain hydrophobic content in the drug, needed to impart the irreversibility in the antiviral effect. We show that when both elements are present, a virucidal non-toxic drug can be achieved either with gold nanoparticles or with cyclodextrins. With these materials several human influenza strains of type A and B were inhibited with virucidal mechanism. Furthermore, ex-vivo and in-vivo antiviral activity of the nanomaterials with cyclodextrin core was investigated against a very aggressive influenza A strain. Ex-vivo studies clearly demonstrated that the mechanism of inhibition is virucidal. In the in-vivo studies, nanomaterials prevented the mice to loose weight and body temperature; significantly reduced the virus concentration in the lungs and in the nose. These materials can be further developed to target animal strains of the influenza virus. This is particularly important since influenza pandemics usually appear when humans are infected with a new animal strain such as avian and swine influenza.

EPFL2019

Interferon Lambda Delays the Emergence of Influenza Virus Resistance to Oseltamivir

Paulo Henrique Jacob Silva, Chiara Medaglia, Francesco Stellacci

Influenza viruses are a leading cause of morbidity and mortality worldwide. These air-borne pathogens are able to cross the species barrier, leading to regular seasonal epidemics and sporadic pandemics. Influenza viruses also possess a high genetic variability, which allows for the acquisition of resistance mutations to antivirals. Combination therapies with two or more drugs targeting different mechanisms of viral replication have been considered an advantageous option to not only enhance the effectiveness of the individual treatments, but also reduce the likelihood of resistance emergence. Using an in vitro infection model, we assessed the barrier to viral resistance of a combination therapy with the neuraminidase inhibitor oseltamivir and human interferon lambda against the pandemic H1N1 A/Netherlands/602/2009 (H1N1pdm09) virus. We serially passaged the virus in a cell line derived from human bronchial epithelial cells in the presence or absence of increasing concentrations of oseltamivir alone or oseltamivir plus interferon lambda. While the treatment with oseltamivir alone quickly induced the emergence of antiviral resistance through a single mutation in the neuraminidase gene, the co-administration of interferon lambda delayed the emergence of drug-resistant influenza virus variants. Our results suggest a possible clinical application of interferon lambda in combination with oseltamivir to treat influenza.

2021

Polyanionic Amphiphilic Dendritic Polyglycerols as Broad-Spectrum Viral Inhibitors with a Virucidal Mechanism

Valeria Cagno, Matteo Gasbarri, Francesco Stellacci

Heparin has been known to be a broad-spectrum inhibitor of viral infection for almost 70 years, and it has been used as a medication for almost 90 years due to its anticoagulant effect. This nontoxic biocompatible polymer efficiently binds to many types of viruses and prevents their attachment to cell membranes. However, the anticoagulant properties are limiting their use as an antiviral drug. Many heparin-like compounds have been developed throughout the years; however, the reversible nature of the virus inhibition mechanism has prevented their translation to the clinics. In vivo, such a mechanism requires the unrealistic maintenance of the concentration above the binding constant. Recently, we have shown that the addition of long hydrophobic linkers to heparin-like compounds renders the interaction irreversible while maintaining the low-toxicity and broad-spectrum activity. To date, such hydrophobic linkers have been used to create heparin-like gold nanopartides and beta-cydodextrins. The former achieves a nanomolar inhibition concentration on a non-biodegradable scaffold. The latter, on a fully biodegradable scaffold, shows only a micromolar inhibition concentration. Here, we report that the addition of hydrophobic linkers to a new type of multifunctional scaffold (dendritic polyglycerol, dPG) creates biocompatible compounds endowed with nanomolar activity. Furthermore, we present an in-depth analysis of the molecular design rules needed to achieve irreversible virus inhibition. The most active compound (dPG-5) showed nanomolar activity against herpes simplex virus 2 (HSV-2) and respiratory syncytial virus (RSV), giving a proof-of-principle for broad-spectrum while keeping low-toxicity. In addition, we demonstrate that the virucidal activity leads to the release of viral DNA upon the interaction between the virus and our polyanionic dendritic polymers. We believe that this paper will be a stepping stone toward the design of a new dass of irreversible nontoxic broad-spectrum antivirals.