Biology subjects

Vazquez, L.

Publications and source records attributed to Vazquez, L..

3 recordsLinked to original sources

bioRxiv2025

Effects of cell growth and temperature on mitochondrial physiology of Drosophila melanogaster embryonic cell line

The fruit fly Drosophila melanogaster is a valuable model for studying cellular and metabolic processes conserved with mammals. Using its embryonic Schneider S2 cell line, commonly used for heterologous protein expression, we investigated how culture duration and slight temperature changes affect mitochondrial physiology via high-resolution respirometry. We assessed five mitochondrial bioenergetic parameters and two coupling parameters at early and late growth phases, and at two temperatures (26{degrees}C and 28{degrees}C). We observed that a moderate temperature increase coupled with late growth phase synergistically enhanced basal, OXPHOS, and leak respiration, with only minor impacts on mitochondrial coupling efficiency. Notably, spare and maximal respiratory capacities increased disproportionately with either cell growth progression or moderate temperature rise, suggestive of enhanced mitochondrial biogenesis. These results demonstrate that small temperature increases and cell maturation activate mitochondrial bioenergetic capacity through mechanisms consistent with mitochondrial biogenesis and functional remodeling. Such adaptations improve cellular metabolic resilience while maintaining energy conversion efficiency. These findings deepen understanding of mitochondrial plasticity in response to environmental and developmental signals. They may inform strategies to optimize mitochondrial physiology in various biological contexts, including aging, metabolic diseases, and stress adaptation.

biochemistry↗

bioRxiv2021

Atazanavir is a competitive inhibitor of SARS-CoV-2 Mpro, impairing variants replication in vitro and in vivo

Atazanavir (ATV) has already been considered as a potential repurposing drug to 2019 coronavirus disease (COVID-19), however, there are controversial reports on its mechanism of action and effectiveness as anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Through the pre-clinical chain of experiments: enzymatic, molecular docking, cell-based, and in vivo assays, it is demonstrated here that both SARS-CoV-2 B.1 lineage and variant of concern gamma are susceptible to this antiretroviral. Enzymatic assays and molecular docking calculations showed that SARS-CoV-2 main protease (Mpro) was inhibited by ATV, with Morrisons inhibitory constant (Ki) 1.5-fold higher than boceprevir (GC376, a positive control). ATV was a competitive inhibition, increasing the Mpros Michaelis-Menten (Km) more than 6-fold. Cell-based assays indicated that SARS-CoV-2 gamma is more susceptible to ATV than its predecessor strain B.1. Using oral administration of ATV in mice to reach plasmatic exposure similar to humans, transgenic mice expression in human angiotensin converting enzyme 2 (K18-hACE2) were partially protected against lethal challenge with SARS-CoV-2 gamma. Moreover, less cell death and inflammation were observed in the lung from infected and treated mice. Our studies may contribute to a better comprehension of the Mpro/ATV interaction, which could pave the way to the development of specific inhibitors of this viral protease.

pharmacology and toxicology↗

bioRxiv2021

Apixaban, an orally available anticoagulant, inhibits SARS-CoV-2 replication by targeting its major protease in a non-competitive way

Anticoagulants are associated with clinical benefit against the 2019 coronavirus disease (COVID-19), preventing COVID-19 associated coagulopathy. Blood coagulation factor Xa (FXa) and SARS-CoV-2 major protease (Mpro) share over 80% homology at the three-dimensional protein level. Thus, it is worth interrogating whether there is crosstalk between inhibitors and substrates between these enzymes. Here, we found that the clinically-approved FXa inhibitor apixaban targets SARS-CoV-2 Mpro with a 21-fold higher potency than boceprevir (GC376). Apixaban displayed a non-competitive mechanism of inhibition towards Mpro, since it targets the enzyme/substrate complex and the allosteric site onto the viral protease. Enzymatic assays were further validated in infected Calu-3 cells, which reveal that apixaban decreases the production of infectious viral particles in a dose-dependent manner, with an inhibitory potency in the micromolar range. Our results are in line with the proposed early use of anticoagulants, including FXa inhibitors, to improve clinical outcome of COVID-19 patients. In this context, apixaban may display a dual mechanism of action by targeting FXa to prevent coagulopathy and, at some level, SARS-CoV-2 Mpro.

microbiology↗