Hotspots for mutations in the SARS-CoV-2 spike glycoprotein: a correspondence analysis

Elesclomol, a copper-transporting therapeutic agent targeting mitochondria: from discovery to its novel applications

Copper (Cu) is an essential element that is involved in a variety of biochemical processes. Both deficiency and accumulation of Cu are associated with various diseases; and a high amount of accumulated Cu in cells can be fatal. The production of reactive oxygen species (ROS), oxidative stress, and cuproptosis are among the proposed mechanisms of copper toxicity at high concentrations. Elesclomol (ELC) is a mitochondrion-targeting agent discovered for the treatment of solid tumors. In this review, we summarize the synthesis of this drug, its mechanisms of action, and the current status of its applications in the treatment of various diseases such as cancer, tuberculosis, SARS-CoV-2 infection, and other copper-associated disorders. We also provide some detailed information about future directions to improve its clinical performance.

Identification of SARS-CoV-2 variants in wastewater using targeted amplicon sequencing during a low COVID-19 prevalence period in Japan

Wastewater-based epidemiology is expected to be able to identify SARS-CoV-2 variants at an early stage via next-generation sequencing. In the present study, we developed a highly sensitive amplicon sequencing method targeting the spike gene of SARS-CoV-2, which allows for sequencing viral genomes from wastewater containing a low amount of virus. Primers were designed to amplify a relatively long region (599 bp) around the receptor-binding domain in the SARS-CoV-2 spike gene, which could distinguish initial major variants of concern. To validate the methodology, we retrospectively analyzed wastewater samples collected from a septic tank installed in a COVID-19 quarantine facility between October and December 2020. The relative abundance of D614G mutant in SARS-CoV-2 genomes in the facility wastewater increased from 47.5 % to 83.1 % during the study period. The N501Y mutant, which is the characteristic mutation of the Alpha-like strain, was detected from wastewater collected on December 24, 2020, which agreed with the fact that a patient infected with the Alpha-like strain was quarantined in the facility on this date. We then analyzed archived municipal wastewater samples collected between November 2020 and January 2021 that contained low SARS-CoV-2 concentrations ranging from 0.23 to 0.43 copies/qPCR reaction (corresponding to 3.30 to 4.15 log₁₀ copies/L). The targeted amplicon sequencing revealed that the Alpha-like variant with D614G and N501Y mutations was present in municipal wastewater collected on December 4, 2020 and later, suggesting that the variant had already spread in the community before its first clinical confirmation in Japan on December 25, 2020. These results demonstrate that targeted amplicon sequencing of wastewater samples is a powerful surveillance tool applicable to low COVID-19 prevalence periods and may contribute to the early detection of emerging variants.

Radu E, Matei L, Maria Ruta S, Bleotu C. SARS-CoV-2 Variant Surveillance in Genomic Medicine Era

In the genomic medicine era, the emergence of SARS-CoV-2 was immediately followed by viral genome sequencing and world-wide sequences sharing. Almost in real-time, based on these sequences, resources were developed and applied around the world, such as molecular diagnostic tests, informed public health decisions, and vaccines. Molecular SARS-CoV-2 variant surveillance was a normal approach in this context yet, considering that the viral genome modification occurs commonly in viral replication process, the challenge is to identify the modifications that significantly affect virulence, transmissibility, reduced effectiveness of vaccines and therapeutics or failure of diagnostic tests. However, assessing the importance of the emergence of new mutations and linking them to epidemiological trend, is still a laborious process and faster phenotypic evaluation approaches, in conjunction with genomic data, are required in order to release timely and efficient control measures.

Structural Profiles of SARS-CoV-2 Variants in India

India was severely affected by several waves of SARS-CoV-2 infection that occurred during April-June 2021 (second wave) and December 2021-January 2022 (third wave) and thereafter, resulting in >10 million new infections and a significant number of deaths. Global Initiative on Sharing Avian Influenza Data database was used to collect the sequence information of ~10,000 SARS-CoV-2 patients from India and our sequence analysis identified three variants B.1.1.7 (alpha, α), B1.617.2 (delta, Δ), B.1.1.529 (Omicron, Oo) and one Omicron sub-variant BA.2.75 as the primary drivers for SARS-CoV-2 waves in India. Structural visualization and analysis of important mutations of alpha, delta, Omicron and its sub-variants of SARS-CoV-2 Receptor-Binding Domain (RBD) was performed and our analysis clearly shows that mutations occur throughout the RBD, including the RBD surface responsible for human angiotensin-converting enzyme 2 (hACE-2) receptor-binding. A comparison between alpha, delta and omicron variants/sub-variants reveals many omicron mutations in the hACE-2 binding site and several other mutations within 5 Å of this binding region. Further, computational analysis highlights the importance of electrostatic interactions in stabilizing RBD-hACE-2-binding, especially in the omicron variant. Our analysis explores the likely role of key alpha, delta and omicron mutations on binding with hACE-2. Taken together, our study provides novel structural insights into the implications of RBD mutations in alpha, delta and omicron and its sub-variants that were responsible for India's SARS-CoV-2 surge.

Virus Diversity, Abundance, and Evolution in Three Different Bat Colonies in Switzerland

Bats are increasingly recognized as reservoirs for many different viruses that threaten public health, such as Hendravirus, Ebolavirus, Nipahvirus, and SARS- and MERS-coronavirus. To assess spillover risk, viromes of bats from different parts of the world have been investigated in the past. As opposed to most of these prior studies, which determined the bat virome at a single time point, the current work was performed to monitor changes over time. Specifically, fecal samples of three endemic Swiss bat colonies consisting of three different bat species were collected over three years and analyzed using next-generation sequencing. Furthermore, single nucleotide variants of selected DNA and RNA viruses were analyzed to investigate virus genome evolution. In total, sequences of 22 different virus families were found, of which 13 are known to infect vertebrates. Most interestingly, in a Vespertilio murinus colony, sequences from a MERS-related beta-coronavirus were consistently detected over three consecutive years, which allowed us to investigate viral genome evolution in a natural reservoir host.

SARS-CoV-2 Viroporins: A Multi-Omics Insight from Nucleotides to Amino Acids

COVID-19 is caused by SARS-CoV-2 which has so far affected more than 500 million people worldwide and killed over 6 million as of 1 May 2022. The approved emergency-use vaccines were lifesaving in such a devastating pandemic. Inflammation-related pathways have been well documented to be upregulated in the case of SARS-CoV-2 in rodents, non-human primates and human samples. We reanalysed a previously published dataset to understand if certain molecular components of inflammation could be higher in infected samples. Mechanistically, viroporins are important players in the life cycle of SARS-CoV-2 and are primary to its pathogenesis. We studied the two prominent viroporins of SARS-CoV-2 (i) Orf3a and (ii) envelope (E) protein from a sequence and structural point of view. Orf3a is a cation-selective viral ion channel which has been shown to disrupt the endosomal pathways. E protein is one of the most conserved proteins among the SARS-CoV proteome which affects the ERGIC-related pathways. The aqueous medium through the viroporins mediates the non-selective translocation of cations, affecting ionic homeostasis in the host cellular compartments. We hypothesize a possible mechanistic approach whereby the ionic imbalance caused by viroporin action could potentially be one of the major pathogenic drivers leading to the increased inflammatory response in the host cell. Our results shed light into the transcriptomic, genomic and structural proteomics aspects of widely studied SARS-CoV-2 viroporins, which can be potentially leveraged for the development of antiviral therapeutics.

Methodology-Centered Review of Molecular Modeling, Simulation, and Prediction of SARS-CoV-2

Despite tremendous efforts in the past two years, our understanding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), virus-host interactions, immune response, virulence, transmission, and evolution is still very limited. This limitation calls for further in-depth investigation. Computational studies have become an indispensable component in combating coronavirus disease 2019 (COVID-19) due to their low cost, their efficiency, and the fact that they are free from safety and ethical constraints. Additionally, the mechanism that governs the global evolution and transmission of SARS-CoV-2 cannot be revealed from individual experiments and was discovered by integrating genotyping of massive viral sequences, biophysical modeling of protein-protein interactions, deep mutational data, deep learning, and advanced mathematics. There exists a tsunami of literature on the molecular modeling, simulations, and predictions of SARS-CoV-2 and related developments of drugs, vaccines, antibodies, and diagnostics. To provide readers with a quick update about this literature, we present a comprehensive and systematic methodology-centered review. Aspects such as molecular biophysics, bioinformatics, cheminformatics, machine learning, and mathematics are discussed. This review will be beneficial to researchers who are looking for ways to contribute to SARS-CoV-2 studies and those who are interested in the status of the field.

A unique antigen against SARS-CoV-2, Acinetobacter baumannii, and Pseudomonas aeruginosa

The recent outbreak of COVID-19 has increased hospital admissions, which could elevate the risk of nosocomial infections, such as A. baumannii and P. aeruginosa infections. Although effective vaccines have been developed against SARS-CoV-2, no approved treatment option is still available against antimicrobial-resistant strains of A. baumannii and P. aeruginosa. In the current study, an all-in-one antigen was designed based on an innovative, state-of-the-art strategy. In this regard, experimentally validated linear epitopes of spike protein (SARS-CoV-2), OmpA (A. baumannii), and OprF (P. aeruginosa) were selected to be harbored by mature OmpA as a scaffold. The selected epitopes were used to replace the loops and turns of the barrel domain in OmpA; OprF_311–341 replaced the most similar sequence within the OmpA, and three validated epitopes of OmpA were retained intact. The obtained antigen encompasses five antigenic peptides of spike protein, which are involved in SARS-CoV-2 pathogenicity. One of these epitopes, viz. QTQTNSPRRARSV could trigger antibodies preventing super-antigenic characteristics of spike and alleviating probable autoimmune responses. The designed antigen could raise antibodies neutralizing emerging variants of SARS-CoV-2 since at least two epitopes are consensus. In conclusion, the designed antigen is expected to raise protective antibodies against SARS-CoV-2, A. baumannii, and P. aeruginosa.