CD83 mediates the inhibitory effect of the S1PR1 agonist CYM5442 on LPS-induced M1 polarization of macrophages through the ERK-STAT-1 signaling pathway.

Macrophages possess M1/M2 polarization, which perform an essential role in immunology and inflammation studies. However, few studies have investigated the specific molecules involved in the polarization process beyond its induction and characterization. Here, we determined that the molecule S1PR1 regulates M1 polarization in macrophages and that the surface marker CD83 is involved in this process. The S1PR1 agonist CYM5442 specifically increases CD83 expression in macrophages. Although the agonist CYM5442 and LPS regulate CD83 differently in macrophages, they have a synergistic effect that enhances CD83 expression. Notably, CYM5442 does not act synergistically with IL-4 regarding CD83 expression and does not affect IL-4-induced macrophage M2 polarization. Furthermore, CYM5442 inhibits the expression of LPS-induced inflammatory cytokines and the phosphorylation of ERK1/2 and STAT-1 in macrophages. However, this inhibition was significantly diminished or absent when CD83 is deficient, highlighting the importance of CD83 in mediating S1PR1 signaling in LPS-induced M1 polarization of macrophages. Overall, our findings provide valuable insights into the molecular mechanisms underlying macrophage polarization, particularly the roles of S1PR1 and CD83 in modulating inflammatory responses.

Oxidative stability of chelated Sn(II)(aq) at neutral pH: The critical role of NO3- ions.

Tin(II) compounds are versatile materials with applications across fields such as catalysis, diagnostic imaging, and therapeutic drugs. However, oxidative stabilization of Sn(II) has remained an unresolved challenge as its reactivity with water and dioxygen results in loss of functionality, limiting technological advancement. Approaches to slow Sn(II) oxidation with chelating ligands or sacrificial electron donors have yielded only moderate improvements. We demonstrate here that the addition of nitrate to pyrophosphate-chelated Sn(II)(aq) suppresses Sn(II) oxidation in water across a broad pH range. Evidence of hydroxyl radical concentration reduction and detection of a radical nitrogen species that only forms in the presence of chelated Sn(II) point to a radical-based reaction mechanism. While this chemistry can be broadly applied, we present that this approach maintains Sn(II)'s antibacterial and anti-inflammatory efficacies as an example of sustained oral chemotherapeutic functionality.

Lymphocyte activation gene 3 served as a potential prognostic and immunological biomarker across various cancer types: a clinical and pan-cancer analysis.

Objectives: Lymphocyte activation gene 3 (LAG3), an inhibitory receptor in T-cell activation, is a negative prognostic factor. However, its impact on tumours has yet to be comprehensively elucidated on a pan-cancer scale. Thus, we aim to reveal its role at the pan-cancer level. Methods: We performed IHC staining on a retrospective cohort of 370 patients. Then we assessed the prognostic effect of LAG3 using Kaplan-Meier survival analysis and multivariate Cox regression analysis. In pan-cancer analysis, we constructed competing endogenous RNA and protein-protein interaction networks, conducted gene set enrichment analysis and identified correlations between LAG3 gene expression and various factors, including clinical characteristics, tumour purity, mutations, tumour immunity and drug sensitivity across 33 cancer types. Results: LAG3 was expressed higher in normal kidney tissues than in tumours. A high level of LAG3 gene expression was an independent prognostic factor for OS (HR = 6.60, 95% CI = 2.43-17.90, P < 0.001) and PFS (HR = 3.44, 95% CI = 1.68-7.10, P < 0.001). In pan-cancer analysis, LAG3 exhibited robust correlations with survival and tumour stages in various cancers. Moreover, LAG3 was strongly associated with immune-related genes, proteins and signalling pathways. LAG3 gene expression was positively associated with increased infiltration of activated immune cells and decreased infiltration of several resting cells. LAG3 gene expression was associated with tumour mutation burden and microsatellite instability in multiple cancers. Conclusion: High LAG3 gene expression was an independent risk factor in kidney neoplasms. It also functioned as a biomarker for prognosis, TIME and immunotherapy efficacy in the pan-cancer dimension.

Metabolic changes induced by heavy metal copper exposure in human ovarian granulosa cells.

Copper (Cu) is a common heavy metal and a hazardous environmental pollutant. Emerging epidemiological evidence suggests that Cu exposure is associated with female infertility, especially ovarian dysfunction. However, the mechanisms underlying ovarian toxicity remain poorly understood. Granulosa cells play crucial roles in follicle development and are the main target cells of environmental pollutants for ovarian toxicity. In this study, we investigated the effects of Cu exposure on human granulosa (KGN) cells by using cell biology and metabolomics methods, and explored the molecular mechanisms of Cu-induced cytotoxicity. We found that Cu reduced cell viability in a dose- and time-dependent manner. Then, metabolomic analyses led to the identification of 279, 368 and 466 differentially expressed metabolites (DEMs) in KGN cells exposed to 10, 60 and 240 µM Cu, respectively. Pathway enrichment analysis revealed that high Cu led to disturbances of glutathione metabolism, nucleotide metabolism, glycerophospholipid and ether lipid metabolism. Using cell biological assays, we found that exposure to high Cu significantly decreased the GSH/GSSG ratio and altered the activities of the antioxidant enzymes SOD and CAT. Exposure to high Cu significantly increased the level of mitochondrial ROS. These findings further supported the results revealed by metabolomic analysis and provided clues for elucidating the mechanism by which Cu interferes with the development of ovarian follicles.

Data-Driven Strain Sensor Design Based on a Knowledge Graph Framework.

Wearable flexible strain sensors require different performance depending on the application scenario. However, developing strain sensors based solely on experiments is time-consuming and often produces suboptimal results. This study utilized sensor knowledge to reduce knowledge redundancy and explore designs. A framework combining knowledge graphs and graph representational learning methods was proposed to identify targeted performance, decipher hidden information, and discover new designs. Unlike process-parameter-based machine learning methods, it used the relationship as semantic features to improve prediction precision (up to 0.81). Based on the proposed framework, a strain sensor was designed and tested, demonstrating a wide strain range (300%) and closely matching predicted performance. This predicted sensor performance outperforms similar materials. Overall, the present work is favorable to design constraints and paves the way for the long-awaited implementation of text-mining-based knowledge management for sensor systems, which will facilitate the intelligent sensor design process.

An evaluation of the effectiveness of four chemical additives on the fermentation characteristics, in vitro digestibility and aerobic stability of total mixed ration silage based on soy sauce residue.

The study aimed to compare the impact of four chemical additives on fermentation characteristics, aerobic stability and in vitro digestibility of total mixed ration (TMR) silage based on soy sauce residue. The TMR (35% soy sauce residue + 45% Napier grass + 20% concentrate) was placed into silos (10 L). The experiment followed the completely random design, treated with different chemical additives: (1) distilled water (control); (2) 0.1% potassium sorbate (SP); (3) 0.1% sodium benzoate (SS); (4) 0.5% calcium propionate (SC); (5) 0.5% sodium diacetate (SD). Total of 100 silos (5 treatments × 4 aerobic exposure days × 5 replicates) were ensiled for 60 days. After exposure to the air, the samples were analyzed for the dynamic change of fermentation parameters at 4, 9 and 15 days, and the data was analyzed as repeated measures. The content of butyric acid and ammonia nitrogen was maintained at a low level. The highest (p < 0.05) lactic acid (LA) content and the lowest (p < 0.05) pH value were measured in SP. At the first 4 days of aerobic exposure, TMR silages treated with four chemical additives were more stable relative to the control, as indicated by the low pH value and yeast counts. Furthermore, the highest (p < 0.05) LA content and the lowest (p < 0.05) pH value indicated that SP performed superior aerobic stability compared with other chemical additives. The SP shows higher (p < 0.05) 72 h cumulative gas production (GP72) and in vitro neutral detergent fiber digestibility (IVNDFD) relative to the control. In conclusion, the SP performed superior in improving fermentation characteristics, aerobic stability and in vitro digestibility of TMR silages based on soy sauce residue.

Silencing of KIAA1429, a N6-methyladenine methyltransferase, inhibits the progression of colon adenocarcinoma via blocking the hypoxia-inducible factor 1 signalling pathway.

KIAA1429 is an important 'writer' of the N6-methyladenine (m6A) modification, which is involved in tumour progression. This study was conducted to explore the mechanism of action of KIAA1429 in colon adenocarcinoma (COAD). KIAA1429-silenced COAD cell and xenograft tumour models were constructed, and the function of KIAA1429 was explored through a series of in vivo and in vitro assays. The downstream mechanisms of KIAA1429 were explored using transcriptome sequencing. Dimethyloxalylglycine (DMOG), an activator of HIF-1α, was used for feedback verification. The expression of KIAA1429 in COAD tumour tissues and cells was elevated, and KIAA1429 exhibited differential expression at different stages of the tumour. Silencing of KIAA1429 inhibited the proliferation, migration, and invasion of HT29 and HCT116 cells. The expression levels of NLRP3, GSDMD and Caspase-1 were decreased in KIAA1429-silenced HT29 cells, indicating the pyroptotic activity was inhibited. Additionally, KIAA1429 silencing inhibited the growth of tumour xenograft. Transcriptome sequencing and reverse transcription quantitative polymerase chain reaction revealed that after KIAA1429 silencing, the expression of AKR1C1, AKR1C2, AKR1C3 and RDH8 was elevated, and the expression of VIRMA, GINS1, VBP1 and ARF3 was decreased. In HT29 cells, KIAA1429 silencing blocked the HIF-1 signalling pathway, accompanied by the decrease in AKT1 and HIF-1α protein levels. The activation of HIF-1 signalling pathway, mediated by DMOG, reversed the antitumour role of KIAA1429 silencing. KIAA1429 silencing inhibits COAD development by blocking the HIF-1 signalling pathway.

Photocontrolled Reversible Solid-Fluid Transitions of Azopolymer Nanocomposites for Intelligent Nanomaterials.

Intelligent polymer nanocomposites are multicomponent and multifunctional materials that show immense potential across diverse applications. However, to exhibit intelligent traits such as adaptability, reconfigurability and dynamic properties, these materials often require a solvent or heating environment to facilitate the mobility of polymer chains and nanoparticles, rendering their applications in everyday settings impractical. Here intelligent azopolymer nanocomposites that function effectively in a solvent-free, room-temperature environment based on photocontrolled reversible solid-fluid transitions via switching flow temperatures (Tfs) are shown. A range of nanocomposites is synthesized through the grafting of Au nanoparticles, Au nanorods, quantum dots, or superparamagnetic nanoparticles with photoresponsive azopolymers. Leveraging the reversible cis-trans photoisomerization of azo groups, the azopolymer nanocomposites transition between solid (Tf above room temperature) and fluid (Tf below room temperature) states. Such photocontrolled reversible solid-fluid transitions empower the rewriting of nanopatterns, correction of nanoscale defects, reconfiguration of complex multiscale structures, and design of intelligent optical devices. These findings highlight Tf-switchable polymer nanocomposites as promising candidates for the development of intelligent nanomaterials operative in solvent-free, room-temperature conditions.

Discrimination of apples from the surrounding Bohai Bay and the loess plateau: A combined study of ICP-MS and UPLC-Q-TOF-MS based element and metabolite fingerprints.

Apples are important fruits in China, and their authentication is beneficial for quality control. However, the differentiation between apples from two primary producing regions, the surrounding Bohai Bay (BHB) and the Loess Plateau (LP), has not been well studied. This study used element and metabolite fingerprints combined with mathematical recognition techniques to discriminate between BHB and LP apples. A total of 235 samples were collected from these regions during 2018-2019. The apple element and metabolite profiles were obtained via instrument analysis. Differential elements and metabolites between BHB and LP apples were identified, and linear and nonlinear discriminant models were constructed. Nonlinear models demonstrated higher accuracy and effectiveness in model optimization. The final random forest (RF) model, constructed with 11 elements and 51 metabolites, achieved a training accuracy of 91.51% and a validation accuracy of 98.57%. This study discriminated between BHB and LP apples, providing a foundation for apple authentication.

Bisphenol A and bisphenol AF co-exposure induced apoptosis of human ovarian granulosa cells via mitochondrial dysfunction.

Bisphenol A (BPA) is a synthetic chemical primarily utilized in the manufacturing of polycarbonate plastics and epoxy resins that are present in various consumer products. While the BPA impacts on female reproductive toxicity have been widely investigated, very little is currently identified about the mixed toxicity of BPA and bisphenol AF (BPAF), another common BPA derivative that is used in many industrial applications. In this study, we assessed the effect of co-exposure of BPA (30 and 50 µM) and BPAF (3 and 5 µM) on mitochondrial dysfunction in human granulosa cells (KGN cells) for 24 h. Our results exhibited that high-concentration bisphenol individual or their mixture exposure of KGN cells induced significant mitochondrial dysfunction by reducing mitochondrial mass, reducing ATP production, and damaging the mitochondrial respiratory chain. In addition, we found that the combination of BPA and BPAF significantly induced mitochondrial stress by increasing calcium levels and the production of ROS in mitochondria. Mitochondrial stress induced by BPA and BPAF was determined to be a mechanism that promoted cell apoptosis after pretreating the cells with the mitochondrial-targeted antioxidant and the calcium chelator. Our results provide novel evidence of the cytotoxicity of mixtures of different bisphenol compounds.

Visual Strain Sensors Based on Fabry-Perot Structures for Structural Integrity Monitoring.

Strain sensors that can rapidly and efficiently detect strain distribution and magnitude are crucial for structural health monitoring and human-computer interactions. However, traditional electrical and optical strain sensors make access to structural health information challenging because data conversion is required, and they have intricate, delicate designs. Drawing inspiration from the moisture-responsive coloration of beetle wing sheaths, we propose using Ecoflex as a flexible substrate. This substrate is coated with a Fabry-Perot (F-P) optical structure, comprising a "reflective layer/stretchable interference cavity/reflective layer", creating a dynamic color-changing visual strain sensor. Upon the application of external stress, the flexible interference chamber of the sensor stretches and contracts, prompting a blue-shift in the structural reflection curve and displaying varying colors that correlate with the applied strain. The innovative flexible sensor can be attached to complex-shaped components, enabling the visual detection of structural integrity. This biomimetic visual strain sensor holds significant promise for real-time structural health monitoring applications.

C9orf72 controls hepatic lipid metabolism by regulating SREBP1 transport.

Sterol regulatory element binding transcription factors (SREBPs) play a crucial role in lipid homeostasis. They are processed and transported to the nucleus via COPII, where they induce the expression of lipogenic genes. COPII maintains the homeostasis of organelles and plays an essential role in the protein secretion pathways in eukaryotes. The formation of COPII begins at endoplasmic reticulum exit sites (ERES), and is regulated by SEC16A, which provides a platform for the assembly of COPII. However, there have been few studies on the changes in SEC16A protein levels. The repetitive expansion of the hexanucleotide sequence GGGGCC within the chromosome 9 open reading frame 72 (C9orf72) gene is a prevalent factor in the development of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here, we found that the absence of C9orf72 leads to a decrease in SEC16A protein levels, resulting in reduced localization of the guanine nucleotide exchange factor SEC12 at the ERES. Consequently, the small GTP binding protein SAR1 is unable to bind the endoplasmic reticulum normally, impairing the assembly of COPII. Ultimately, the disruption of SREBPs transport decreases de novo lipogenesis. These results suggest that C9orf72 acts as a novel role in regulating lipid homeostasis and may serve as a potential therapeutic target for obesity.

Integrated Transcriptomic and Metabolomic Analysis Reveal the Dynamic Process of Bama Hemp Seed Development and the Accumulation Mechanism of α-Linolenic Acid and Linoleic Acid.

Bama County is a world-famous longevity county in the Guangxi Province, China. Bama hemp is a traditional seed used in hemp cultivation in the Bama County. The seeds contain abundant unsaturated fatty acids, particularly linoleic acid (LA) and linolenic acid in the golden ratio. These two substances have been proven to be related to human health and the prevention of various diseases. However, the seed development and seed oil accumulation mechanisms remain unclear. This study employed a combined analysis of physiological, transcriptomic, and metabolomic parameters to elucidate the fatty acid formation patterns in Bama hemp seeds throughout development. We found that seed oil accumulated at a late stage in embryo development, with seed oil accumulation following an "S″-shaped growth curve, and positively correlated with seed size, sugar content, protein content, and starch content. Transcriptome analysis identified genes related to the metabolism of LA, α-linolenic acid (ALA), and jasmonic acid (JA). We found that the FAD2 gene was upregulated 165.26 folds and the FAD3 gene was downregulated 6.15 folds at day 21. Metabolomic changes in LA, ALA, and JA compounds suggested a competitive relationship among these substances. Our findings indicate that the peak period of substance accumulation and nutrient accumulation in Bama hemp seeds occurs during the midstage of seed development (day 21) rather than in the late stage (day 40). The results of this research will provide a theoretical basis for local cultivation and deep processing of Bama hemp.

Bisphenol A and its structural analogues exhibit differential potential to induce mitochondrial dysfunction and apoptosis in human granulosa cells.

Bisphenol A (BPA) is an endocrine disruptor strongly associated with ovarian dysfunction. BPA is being substituted by structurally similar chemicals, such as bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF). However, the toxicity of these analogues in female reproduction remains largely unknown. This study evaluated the effects of BPA and its analogues BPS, BPF, and BPAF on the mitochondrial mass and function, oxidative stress, and their potential to induce apoptosis of human granulosa cells (KGN cells). BPA and its analogues, especially BPA and BPAF, significantly decreased mitochondrial activity and cell viability. The potential of bisphenols to reduce mitochondrial mass and function differed in the following order: BPAF > BPA > BPF > BPS. Flow cytometry revealed that exposure to bisphenols significantly increased mitochondrial ROS levels and increased mitochondrial Ca2+ levels. Thus, bisphenols exposure causes mitochondrial stress in KGN cells. At the same time, bisphenols exposure significantly induced apoptosis. These results thus emphasize the toxicity of these bisphenols to cells. Our study suggests the action mechanism of BPA and its analogues in damage caused to ovarian granulosa cells. Additionally, these novel analogues may be regrettable substitutes, and the biological effects and potential risks of BPA alternatives must be evaluated.

Impact of habitual intake of glucosamine, fresh fruit, and tea on the risk of urolithiasis: A two-sample Mendelian randomization study.

Dietary patterns have a significant impact on the occurrence of urolithiasis. This study aimed to investigate the causal relationships between the consumption of glucosamine, fresh fruits, and tea, and the predisposition to urinary stones using a Mendelian randomization (MR) approach. Genetic proxies for these dietary factors were obtained from the UK Biobank, while the summary data for urolithiasis genome-wide association analyses were sourced from the FinnGen consortium. Five MR methodologies, namely inverse variance weighted (IVW), MR-Egger regression, weighted median, weighted mode, and simple mode, were employed in the analysis. To validate the findings, sensitivity evaluations such as the MR-PRESSO disruption test and Cochran Q test for heterogeneity were performed. The IVW method showed that glucosamine consumption had a strong inverse association with urolithiasis risk (Odds Ratio [OR] = 0.006, 95% Confidence Interval [CI] 0.0001-0.287, P = .009), surpassing the associations of fresh fruits (OR = 0.464, 95% CI 0.219-0.983, P = .045) and tea (OR = 0.550, 95% CI 0.345-0.878, P = .012). These findings were consistent when verified using alternative MR techniques, and the sensitivity analyses further supported their credibility. The results of this MR analysis demonstrate that regular consumption of glucosamine, fresh fruits, and tea is inversely correlated with the risk of developing urolithiasis.

Causal effects of gut microbiota on the risk of urinary tract stones: A bidirectional two-sample mendelian randomization study.

Background: Recent studies increasingly suggest notable changes in both the quantity and types of gut microbiota among individuals suffering from urinary tract stones. However, the causal relationship between GMB and urinary tract stone formation remains elusive, which we aim to further investigate in this research through Mendelian Randomization (MR) analysis. Materials and methods: Single nucleotide polymorphisms (SNPs) associated with the human GMB were selected from MiBioGen International Consortium GWAS dataset. Data on urinary tract stone-related traits and associated SNPs were sourced from the IEU Open GWAS database. To investigate the causal relationships between gut microbiota and urinary tract stones, Mendelian Randomization (MR) was applied using genetic variants as instrumental variables, utilizing a bidirectional two-sample MR framework. This analysis incorporated various statistical techniques such as inverse variance weighting, weighted median analysis, MR-Egger, and the maximum likelihood method. To ensure the reliability of the findings, a range of sensitivity tests were conducted, including Cochran's Q test, the MR-Egger intercept, leave-one-out cross-validation, and examination of funnel plots. Results: The results revealed the causal relationship between the increase in the abundance of 10 microbial taxa, including Genus-Barnesiella (IVW OR = 0.73, 95%CI 0.73-0.89, P = 2.29 × 10-3) and Genus-Flavonifractor (IVW OR = 0.69, 95%CI 0.53-0.91, P = 8.57 × 10-3), and the decreased risk of urinary tract stone formation. Conversely, the development of urinary tract stones was observed to potentially instigate alterations in the abundance of 13 microbial taxa, among which Genus-Ruminococcus torques group was notably affected (IVW OR = 1.07, 95%CI 0.64-0.98, P = 1.86 × 10-3). In this context, Genus-Clostridium sensustricto1 exhibited a bidirectional causal relationship with urinary tract stones, while the remaining significant microbial taxa demonstrated unidirectional causal effects in the two-sample MR analysis. Sensitivity analyses did not identify significant estimates of heterogeneity or pleiotropy. Conclusion: To summarize, the results of this study suggest a likely causative link between gut microbiota and the incidence of urinary tract stones. This insight opens up potential pathways for discovering biomarkers and therapeutic targets in the management and prevention of urolithiasis. However, further in-depth research is warranted to investigate these associations.

Molecular mechanisms of cadmium-induced cytotoxicity in human ovarian granulosa cells identified using integrated omics.

Epidemiological and clinical data have demonstrated that exposure to cadmium (Cd), a toxic heavy metal, is associated with an increased risk of female infertility. Granulosa cells, the main somatic cells comprising ovarian follicles, are one of the main targets of Cd in the ovaries. However, the mechanism by which Cd induces cytotoxicity in granulosa cells has not been fully elucidated. In this study, we exposed human ovarian granulosa cells (KGN cells) to Cd and conducted in vitro cell experiments and multi-omics (metabolomics and transcriptomics) methods to elucidate these mechanisms. Cd exposure was found to not only induce the apoptosis of the KGN cells but also further reduced mitochondrial function by decreasing mitochondrial membrane potential, ATP production, and respiratory chain complex activity as well as increasing mitochondrial reactive oxygen species (ROS) production. A total of 443 differentially expressed metabolites (160 upregulated and 283 downregulated) and 5200 differentially expressed genes (4634 upregulated and 566 downregulated) were observed in the Cd exposed-cells. The multi-omics data showed that Cd interfered with citric acid cycle (TCA cycle), amino acid (including alanine, glycine, serine, threonine, arginine, and proline) metabolism, and calcium signaling. These findings help to better elucidate the potential toxicity mechanisms of Cd on granulosa cells and the ovary.

In vivo base editing rescues primary hyperoxaluria type 1 in rats.

Primary hyperoxaluria type 1 (PH1) is a childhood-onset autosomal recessive disease, characterized by nephrocalcinosis, multiple recurrent urinary calcium oxalate stones, and a high risk of progressive kidney damage. PH1 is caused by inherent genetic defects of the alanine glyoxylate aminotransferase (AGXT) gene. The in vivo repair of disease-causing genes was exceedingly inefficient before the invention of base editors which can efficiently introduce precisely targeted base alterations without double-strand DNA breaks. Adenine base editor (ABE) can precisely convert A·T to G·C with the assistance of specific guide RNA. Here, we demonstrated that systemic delivery of dual adeno-associated virus encoding a split-ABE8e could artificially repair 13% of the pathogenic allele in AgxtQ84X rats, a model of PH1, alleviating the disease phenotype. Specifically, ABE treatment partially restored the expression of alanine-glyoxylate-aminotransferase (AGT), reduced endogenous oxalate synthesis and alleviated calcium oxalate crystal deposition. Western blot and immunohistochemistry confirmed that ABE8e treatment restored AGT protein expression in hepatocytes. Moreover, the precise editing efficiency in the liver remained stable six months after treatment. Thus, our findings provided a prospect of in vivo base editing as a personalized and precise medicine for PH1 by directly correcting the mutant Agxt gene.

Discovery of 3-oxo-1,2,3,4-tetrahydropyrido[1,2-a]pyrazin derivatives as SARS-CoV-2 main protease inhibitors through virtual screening and biological evaluation.

The COVID-19 caused by SARS-CoV-2 has led to a global pandemic that continues to impact societies and economies worldwide. The main protease (Mpro) plays a crucial role in SARS-CoV-2 replication and is an attractive target for anti-SARS-CoV-2 drug discovery. Herein, we report a series of 3-oxo-1,2,3,4-tetrahydropyrido[1,2-a]pyrazin derivatives as non-peptidomimetic inhibitors targeting SARS-CoV-2 Mpro through structure-based virtual screening and biological evaluation. Further similarity search and structure-activity relationship study led to the identification of compound M56-S2 with the enzymatic IC50 value of 4.0 µM. Moreover, the molecular simulation and predicted ADMET properties, indicated that non-peptidomimetic inhibitor M56-S2 might serve as a useful starting point for the further discovery of highly potent inhibitors targeting SARS-CoV-2 Mpro.

Unveiling Enhanced Electrostatic Repulsion in Silica Nanosphere Assembly: Formation Dynamics of Body-Centered-Cubic Colloidal Crystals.

We demonstrate the effective establishment of long-range electrostatic interactions among colloidal silica nanospheres through acid treatment, enabling their assembly into colloidal crystals at remarkably low concentrations. This novel method overcomes the conventional limitation in colloidal silica assembly by removing entrapped NH4+ ions and enhancing the electrical double layer (EDL) thickness, offering a time-efficient alternative to increase electrostatic interactions compared with methods like dialysis. The increased EDL thickness facilitates the assembly of SiO2 nanospheres into a body-centered-cubic lattice structure at low particle concentrations, allowing for broad spectrum tunability and high tolerance to particle size polydispersity. Further, we uncover a disorder-order transition during colloidal crystallization at low particle concentrations, with the optimal concentration for crystal formation governed by both thermodynamic and kinetic factors. This work not only provides insights into assembly mechanisms but also paves the way for the design and functionalization of colloidal silica-based photonic crystals in diverse applications.