Biology subjects

Raich-Regue, D.

Publications and source records attributed to Raich-Regue, D..

3 recordsLinked to original sources

bioRxiv2022

Beta-Cyclodextrins as affordable antivirals to treat coronavirus infection

The SARS-CoV-2 pandemic made evident that we count with few coronavirus-fighting drugs. Here we aimed to identify a cost-effective antiviral with broad spectrum activity and high safety and tolerability profiles. We began elaborating a list of 116 drugs previously used to treat other pathologies or characterized in pre-clinical studies with potential to treat coronavirus infections. We next employed molecular modelling tools to rank the 44 most promising inhibitors and tested their efficacy as antivirals against a panel of and {beta} coronavirus, e.g., the HCoV-229E and SARS-CoV-2 viruses. Four drugs, OSW-1, U18666A, hydroxypropyl-{beta}-cyclodextrin (H{beta}CD) and phytol, showed antiviral activity against both HCoV-229E (in MRC5 cells) and SARS-CoV-2 (in Vero E6 cells). The mechanism of action of these compounds was studied by transmission electron microscopy (TEM) and by testing their capacity to inhibit the entry of SARS-CoV-2 pseudoviruses in ACE2-expressing HEK-293T cells. The entry was inhibited by H{beta}CD and U18666A, yet only H{beta}CD could inhibit SARS-CoV-2 replication in the pulmonary cells Calu-3. With these results and given that cyclodextrins are widely used for drug encapsulation and can be safely administered to humans, we further tested 6 native and modified cyclodextrins, which confirmed {beta}-cyclodextrins as the most potent inhibitors of SARS-CoV-2 replication in Calu-3 cells. All accumulated data points to {beta}-cyclodextrins as promising candidates to be used in the therapeutic treatments for SARS-CoV-2 and possibly other respiratory viruses.

microbiology↗

bioRxiv2021

Unraveling the antiviral activity of plitidepsin by subcellular and morphological analysis

The pandemic caused by the new coronavirus SARS-CoV-2 has made evident the need for broad-spectrum, efficient antiviral treatments to combat emerging and re-emerging viruses. Plitidepsin is an antitumor agent of marine origin that has also shown a potent pre-clinical efficacy against SARS-CoV-2. Plitidepsin targets the host protein eEF1A (eukaryotic translation factor 1 alpha 1) and affects viral infection at an early, post-entry step. Because electron microscopy is a valuable tool to study virus-cell interactions and the mechanism of action of antiviral drugs, in this work we have used transmission electron microscopy (TEM) to evaluate the effects of plitidepsin in SARS-CoV-2 infection in cultured Vero E6 cells 24 and 48h post-infection. In the absence of plitidepsin, TEM morphological analysis showed double-membrane vesicles (DMVs), organelles that support coronavirus genome replication, single-membrane vesicles with viral particles, large vacuoles with groups of viruses and numerous extracellular virions attached to the plasma membrane. When treated with plitidepsin, no viral structures were found in SARS-CoV-2-infected Vero E6 cells. Immunogold detection of SARS-CoV-2 nucleocapsid (N) protein and double-stranded RNA (dsRNA) provided clear signals in cells infected in the absence of plitidepsin, but complete absence in cells infected and treated with plitidepsin. The present study shows that plitidepsin completely blocks the biogenesis of viral replication organelles and the morphogenesis of virus progeny. Electron microscopy morphological analysis coupled to immunogold labeling of SARS-CoV-2 products offers a unique approach to understand how antivirals such as plitidepsin work.

microbiology↗

bioRxiv2021

SARS-CoV-2 B.1.351 (beta) variant shows enhanced infectivity in K18-hACE2 transgenic mice and expanded tropism to wildtype mice compared to B.1 variant

SARS-CoV-2 variants display enhanced transmissibility and/or immune evasion and can be generated in humans or animals, like minks, thus generating new reservoirs. The continuous surveillance of animal susceptibility to new variants is necessary to predict pandemic evolution. In this study we demonstrate that, compared to the B.1 SARS-CoV-2 variant, K18-hACE2 transgenic mice challenged with the B.1.351 variant displayed a faster progression of infection. Furthermore, we also report that B.1.351 can establish infection in wildtype mice, while B.1 cannot. B.1.351-challenged wildtype mice showed a milder infection than transgenic mice, confirmed by detectable viral loads in oropharyngeal swabs and tissues, lung pathology, immunohistochemistry and serology. In silico models supported these findings by demonstrating that the Spike mutations in B.1.351 resulted in increased affinity for both human and murine ACE2 receptors. Overall, this study highlights the plasticity of SARS-CoV-2 animal susceptibility landscape, which may contribute to viral persistence and expansion.

microbiology↗