SARS-CoV-2 Mpro inhibitor identification using a cellular gain-of-signal assay for high-throughput screening.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2, SARS2) is responsible for the COVID-19 pandemic and infections that continue to affect the lives of millions of people worldwide, especially those who are older and/or immunocompromised. The SARS2 main protease enzyme, Mpro (also called 3C-like protease, 3CLpro), is a bona fide drug target as evidenced by potent inhibition with nirmatrelvir and ensitrelvir, the active components of the drugs Paxlovid and Xocova, respectively. However, the existence of nirmatrelvir and ensitrelvir-resistant isolates underscores the need to develop next-generation drugs with different resistance profiles and/or distinct mechanisms of action. Here, we report the results of a high-throughput screen of 649,568 compounds using a cellular gain-of-signal assay. In this assay, Mpro inhibits expression of a luciferase reporter, and 8,777 small molecules were considered hits by causing a gain in luciferase activity 3x SD above the sample field activity (6.8% gain-of-signal relative to 100 µM GC376). Single concentration and dose-response gain-of-signal experiments confirmed 3,522/8,762 compounds as candidate inhibitors. In parallel, all initial high-throughput screening hits were tested in a peptide cleavage assay with purified Mpro and only 39/8,762 showed inhibition. Importantly, 19/39 compounds (49%) re-tested positive in both SARS2 assays, including two previously reported Mpro inhibitors, demonstrating the efficacy of the overall screening strategy. This approach led to the rediscovery of known Mpro inhibitors such as calpain inhibitor II, as well as to the discovery of novel compounds that provide chemical information for future drug development efforts.

Incorporation of Nanostructural Hydroxyapatite and Curcumin Extract from Curcuma longa L. Rhizome into Polylactide to Obtain Green Composite.

This study showed that a polylactide (PLA)-based composite filled with nanostructured hydroxyapatite (HAp) and a natural extract from the rhizome of Curcuma longa L. could provide an alternative to commonly used fossil-based plasticsfor food packaging. The incorporation of HAp into the PLA matrix had a positive effect on improving selected properties of the composites; the beneficial effect could be enhanced by introducing a green modifier in the form of an extract. Prior to the fabrication of the composite, the filler was characterized in terms of morphology and composition, and the composite was then fully characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman and Fourier transform infrared spectroscopy (FT-IR), and the mechanical, thermal, thermomechanical, and optical properties were investigated. The proposed material exhibits antioxidant properties against DPPH radicals and antibacterial performance against Escherichia coli (E. coli). The results showed that the nanocomposite has the highest antioxidant and antibacterial properties for 10 wt% HAp with an average diameter of rod-shaped structures below 100 nm. In addition, the introduction of turmeric extract had a positive effect on the tensile strength of the nanocomposites containing 1 and 5% HAp. As the resulting material adsorbs light in a specific wavelength range, it can be used in the medical sector, food-packaging, or coatings.

Elastography of nerves in the wrists of cyclists.

Purpose: This study aimed to investigate changes in the elasticity of the median and ulnar nerves in cyclists. Material and methods: The study included 30 cyclists and 2 non-biking reference groups that included 32 healthy volunteers and 32 individuals with ulnar nerve entrapment neuropathies. All participants underwent physical, ultrasonographic, and elastographic examinations including assessment of nerve cross-sectional area (CSA) and stiffness (SWE). The cyclists' group was tested before and after a 2-hour workout. Results: The values of ulnar nerve CSA and stiffness in Guyon's canal in resting cyclists were 5.30 ± 1.51 mm2 and 49.05 ± 11.18 kPa, respectively. These values were significantly higher than in the healthy volunteers, but not higher than in the nerve entrapment group. Median nerve CSA and stiffness at rest were 9.10 ± 2.61 mm2 and 38.54 ± 14.87 kPa, respectively. Both values were higher than respective values in the healthy group. Cycling induced an increase in all these parameters, although the increase in nerve stiffness was more noticeable than in CSA. Conclusions: The elasticity of the median and ulnar nerve in cyclists remains within normal limits, questioning the belief that cyclists are at risk of nerve palsy in Guyon's canal. However, cycling workout does exert compression, resulting in transient oedema of both nerves. The dynamics of changes was more noticeable in SWE examination than in conventional ultrasound, which may depend on SWE sensitivity.

Tracking the micro- and nanoplastics in the terrestrial-freshwater food webs. Bivalves as sentinel species.

Micro- (MPs) and nanoplastics (NPs) are currently ubiquitous in the ecosystems, and freshwater biota is still insufficiently studied to understand the global fate, transport paths, and consequences of their presence. Thus, in this study, we investigated the role of bivalves and a trophic transfer of MPs and NPs in an experimental food chain. The food chain consisted of terrestrial non-selective detritivore Dendrobaena (Eisenia) sp., freshwater benthic filter feeder Unio tumidus, and freshwater benthic detritivore-collectors Asellus aquaticus or Gammarus sp. Animals were exposed to different fluorescently labeled micro- and nanoplastics (PMMA 20 µm, nanoPS 15-18 nm, and 100 nm, PS 1 µm and 20 µm, PE from cosmetics) as well as to the faeces of animals exposed to plastics to assess their influence on the environmental transportation, availability to biota, and bioaccumulation of supplied particles. Damaged and intact fluorescent particles were observed in the faeces of terrestrial detritivores and in the droppings of aquatic filter feeders, respectively. They were also present in the guts of bivalves and of crustaceans which were fed with bivalve droppings. Bivalves (Unio tumidus, and additionally Unio pictorum, and Sphaerium corneum) produced droppings containing micro- and nanoparticles filtered from suspension and deposited them onto the tank bottom, making them available for broader feeding guilds of animals (e.g. collectors, like crustaceans). Finally, the natural ageing of PS and its morphological changes, leakage of the fluorescent labelling, and agglomeration of particles were demonstrated. That supports our hypothesis of the crucial role of the characterization of physical and chemical materials in adequately understanding the mechanisms of their interaction with biota. Microscopical methods (confocal, fluorescent, scanning electron) and Raman and FT-IR spectroscopy were used to track the particles' passage in a food web and monitor structural changes of the MPs' and NPs' surface.

Trodusquemine (MSI-1436) Restores Metabolic Flexibility and Mitochondrial Dynamics in Insulin-Resistant Equine Hepatic Progenitor Cells (HPCs).

Equine metabolic syndrome (EMS) is a significant global health concern in veterinary medicine. There is increasing interest in utilizing molecular agents to modulate hepatocyte function for potential clinical applications. Recent studies have shown promising results in inhibiting protein tyrosine phosphatase (PTP1B) to maintain cell function in various models. In this study, we investigated the effects of the inhibitor Trodusquemine (MSI-1436) on equine hepatic progenitor cells (HPCs) under lipotoxic conditions. We examined proliferative activity, glucose uptake, and mitochondrial morphogenesis. Our study found that MSI-1436 promotes HPC entry into the cell cycle and protects them from palmitate-induced apoptosis by regulating mitochondrial dynamics and biogenesis. MSI-1436 also increases glucose uptake and protects HPCs from palmitate-induced stress by reorganizing the cells' morphological architecture. Furthermore, our findings suggest that MSI-1436 enhances 2-NBDG uptake by increasing the expression of SIRT1, which is associated with liver insulin sensitivity. It also promotes mitochondrial dynamics by modulating mitochondria quantity and morphotype as well as increasing the expression of PINK1, MFN1, and MFN2. Our study provides evidence that MSI-1436 has a positive impact on equine hepatic progenitor cells, indicating its potential therapeutic value in treating EMS and insulin dysregulation.