Competitive Inhibition of Okanin against Plasmodium falciparum Tyrosyl-tRNA Synthetase.

Malaria is a severe disease that presents a significant threat to human health. As resistance to current drugs continues to increase, there is an urgent need for new antimalarial medications. Aminoacyl-tRNA synthetases (aaRSs) represent promising targets for drug development. In this study, we identified Plasmodium falciparum tyrosyl-tRNA synthetase (PfTyrRS) as a potential target for antimalarial drug development through a comparative analysis of the amino acid sequences and three-dimensional structures of human and plasmodium TyrRS, with particular emphasis on differences in key amino acids at the aminoacylation site. A total of 2141 bioactive compounds were screened using a high-throughput thermal shift assay (TSA). Okanin, known as an inhibitor of LPS-induced TLR4 expression, exhibited potent inhibitory activity against PfTyrRS, while showing limited inhibition of human TyrRS. Furthermore, bio-layer interferometry (BLI) confirmed the high affinity of okanin for PfTyrRS. Molecular dynamics (MD) simulations highlighted the stable conformation of okanin within PfTyrRS and its sustained binding to the enzyme. A molecular docking analysis revealed that okanin binds to both the tyrosine and partial ATP binding sites of the enzyme, preventing substrate binding. In addition, the compound inhibited the production of Plasmodium falciparum in the blood stage and had little cytotoxicity. Thus, okanin is a promising lead compound for the treatment of malaria caused by P. falciparum.

Microcephaly Gene Mcph1 Deficiency Induces p19ARF-Dependent Cell Cycle Arrest and Senescence.

MCPH1 has been identified as the causal gene for primary microcephaly type 1, a neurodevelopmental disorder characterized by reduced brain size and delayed growth. As a multifunction protein, MCPH1 has been reported to repress the expression of TERT and interact with transcriptional regulator E2F1. However, it remains unclear whether MCPH1 regulates brain development through its transcriptional regulation function. This study showed that the knockout of Mcph1 in mice leads to delayed growth as early as the embryo stage E11.5. Transcriptome analysis (RNA-seq) revealed that the deletion of Mcph1 resulted in changes in the expression levels of a limited number of genes. Although the expression of some of E2F1 targets, such as Satb2 and Cdkn1c, was affected, the differentially expressed genes (DEGs) were not significantly enriched as E2F1 target genes. Further investigations showed that primary and immortalized Mcph1 knockout mouse embryonic fibroblasts (MEFs) exhibited cell cycle arrest and cellular senescence phenotype. Interestingly, the upregulation of p19ARF was detected in Mcph1 knockout MEFs, and silencing p19Arf restored the cell cycle and growth arrest to wild-type levels. Our findings suggested it is unlikely that MCPH1 regulates neurodevelopment through E2F1-mediated transcriptional regulation, and p19ARF-dependent cell cycle arrest and cellular senescence may contribute to the developmental abnormalities observed in primary microcephaly.

Structure-Based Virtual Screening, ADMET Properties Prediction and Molecular Dynamics Studies Reveal Potential Inhibitors of Mycoplasma pneumoniae HPrK/P.

Mycoplasma pneumoniae pneumonia (MPP) is a frequent cause of community-acquired pneumonia (CAP) in children. The incidence of childhood pneumonia caused by M. pneumoniae infection has been rapidly increasing worldwide. M. pneumoniae is naturally resistant to beta-lactam antibiotics due to its lack of a cell wall. Macrolides and related antibiotics are considered the optimal drugs for treating M. pneumoniae infection. However, clinical resistance to macrolides has become a global concern in recent years. Therefore, it is imperative to urgently identify new targets and develop new anti-M. pneumoniae drugs to treat MMP. Previous studies have shown that deficiencies in HPrK/P kinase or phosphorylase activity can seriously affect carbon metabolism, growth, morphology, and other cellular functions of M. pneumoniae. To identify potential drug development targets against M. pneumoniae, this study analyzed the sequence homology and 3D structure alignment of M. pneumoniae HPrK/P. Through sequence and structure analysis, we found that HPrK/P lacks homologous proteins in the human, while its functional motifs are highly conserved in bacteria. This renders it a promising candidate for drug development. Structure-based virtual screening was then used to discover potential inhibitors among 2614 FDA-approved drugs and 948 bioactive small molecules for M. pneumoniae HPrK/P. Finally, we identified three candidate drugs (Folic acid, Protokylol and Gluconolactone) as potential HPrK/P inhibitors through molecular docking, molecular dynamics (MDs) simulations, and ADMET predictions. These drugs offer new strategies for the treatment of MPP.

Enhancing bone regeneration and immunomodulation via gelatin methacryloyl hydrogel-encapsulated exosomes from osteogenic pre-differentiated mesenchymal stem cells.

Mesenchymal stem cell-derived exosomes (MSC-Exos) have emerged as promising candidates for cell-free therapy in tissue regeneration. However, the native osteogenic and angiogenic capacities of MSC-Exos are often insufficient to repair critical-sized bone defects, and the underlying immune mechanisms remain elusive. Furthermore, achieving sustained delivery and stable activity of MSC-Exos at the defect site is essential for optimal therapeutic outcomes. Here, we extracted exosomes from osteogenically pre-differentiated human bone marrow mesenchymal stem cells (hBMSCs) by ultracentrifugation and encapsulated them in gelatin methacryloyl (GelMA) hydrogel to construct a composite scaffold. The resulting exosome-encapsulated hydrogel exhibited excellent mechanical properties and biocompatibility, facilitating sustained delivery of MSC-Exos. Osteogenic pre-differentiation significantly enhanced the osteogenic and angiogenic properties of MSC-Exos, promoting osteogenic differentiation of hBMSCs and angiogenesis of human umbilical vein endothelial cells (HUVECs). Furthermore, MSC-Exos induced polarization of Raw264.7 cells from a pro-inflammatory phenotype to an anti-inflammatory phenotype under simulated inflammatory conditions, thereby creating an immune microenvironment conducive to osteogenesis. RNA sequencing and bioinformatics analysis revealed that MSC-Exos activate the p53 pathway through targeted delivery of internal microRNAs and regulate macrophage polarization by reducing DNA oxidative damage. Our study highlights the potential of osteogenic exosome-encapsulated composite hydrogels for the development of cell-free scaffolds in bone tissue engineering.

Ultrasonographic Assessment of Gastric Volume in Fasted Patients Undergoing Gastrointestinal Endoscopy Under Sedation.

Purpose: In this prospective observational study, an ultrasonographic measurement of antral cross-sectional area (ACSA) was conducted to evaluate the gastric content and volume as well as to identify high-risk stomach in non-pregnant adult surgical patients adhering to preanesthetic fasting guidelines. Patients and Methods: Fasted patients undergoing gastrointestinal endoscopy under sedation were included. Ultrasonographic measurements of ACSA were conducted in both semi-recumbent and right lateral decubitus positions before endoscopic procedures. Gastroscopy was employed to guide the measurement of suctioned gastric volume (GV). Ultrasonography was performed to assess gastric contents and identify patients with high-risk stomach. The relationship between ACSA and suctioned GV was also evaluated. Results: ACSA was evaluated in 736 out of 782 patients. A significant positive correlation was discovered between ACSA in the right lateral decubitus position and suctioned GV, which was more reliable than in the semi-recumbent position. To analyze high-risk stomach with a GV > 100 mL, the cutoff value of ACSA in the right lateral decubitus was found to be 7.5 cm2, with the AUC, sensitivity and specificity of 0.80 (95% CI, 0.76-0.82; P<0.001), 82.4% and 67.3%, respectively. A novel mathematical model based on ACSA to estimate GV in non-pregnant fasted adults was presented. Conclusion: Ultrasonographic measurement of ACSA can assist anesthesiologists in estimating the risk of pulmonary aspiration of gastric contents during general anesthesia and sedation.

MiR-135a-5p and Mst1 regulate MPP + -1 induced apoptosis and autophagy in Parkinson's disease model in vitro.

The mammalian Ste20-like kinases 1 (Mst1) is essential for regulating cell proliferation, differentiation, apoptosis, and autophagy. However, the molecular mechanisms of Mst1 in neuronal cell death remains incompletely understood. Here, we showed that Mst1 is up-regulated in Parkinson's disease (PD) model induced by MPP+. Knockdown of Mst1 resulted in a reduction in MPP+-induced apoptosis and autophagy in SH-SY5Y and CHP 212 cells. Mechanistically, Mst1 silencing suppressed autophagy by activating mTOR/ULK1/S6K1 pathway. We also showed that miR-135a-5p was lower while Mst1 was inversely higher in MPP+-treated cells. Furthermore, miR-135a-5p has a protective role on MPP+-induced neuronal cell death via targeting Mst1. On the whole, the miR-135a-5p/Mst1 axis might serve as a potential therapeutic target in PD treatment.

The propofol-induced mitochondrial damage in fetal rat hippocampal neurons via the AMPK/P53 signaling pathway.

Background: Propofol is a commonly used general anesthetic that may cause neuronal damage, especially in infants and young children. Mitochondria play an essential role in cellular metabolism and signal transduction. Propofol may cause neurotoxicity by inhibiting mitochondrial function, but the mechanism by this which occurs remains unclear. Methods: First, the primary rat hippocampal neurons were cultured for 7 days in vitro. The neurons were incubated with propofol at different times or different concentrations, and then the adenosine triphosphate (ATP), reactive oxygen species (ROS), mitochondrial membrane potential, and apoptosis-related proteins were analyzed. Based on the results of the 1st phase, the neurons were then incubated with propofol (100 µM) or corresponding reagents, including 5-aminoimidazole-4-carboxamide ribonucleotide, tenovin-1, and pifithrin-α. Subsequently, the ATP, ROS, mitochondrial membrane potential, phospho-adenosine 5'-monophosphate-activated protein kinase (p-AMPK), protein 53 (p53), and related apoptosis proteins were analyzed. Results: Higher propofol concentrations or longer incubation times were associated with more pronounced decreases in ATP, B-cell lymphoma 2 (Bcl-2), and mitochondrial membrane potential, and more pronounced increases in ROS, BCL2-associated X (Bax), Cytochrome C (CytC), and cleaved caspase-9. Additionally, after incubation with propofol (100 µM), neuronal Bcl-2, p-AMPK, ATP, and mitochondrial membrane potential were downregulated, and ROS, p53, CytC, Bax, cleaved caspase-3, and cleaved caspase-9 were upregulated. AMPK activators or p53 inhibitors reversed the above-mentioned changes. Conclusions: Propofol (100 µM)-induced mitochondrial damage in fetal rat hippocampal neurons may be mediated by the AMPK/p53 signaling pathway. Propofol (100 µM) was shown to inhibit the activity of AMPK in neurons, upregulate the expression of p53, and then activate the mitochondrial-dependent apoptosis pathway, which may lead to neuronal apoptosis.

Propofol protects hippocampal neurons in sleep-deprived rats by inhibiting mitophagy and autophagy.

BACKGROUND: Sleep deprivation (SD) causes a disturbance in the cognitive function of rats. While propofol has a powerful sedative and hypnotic effect and is an antioxidant, its effect on the cognitive function of rats following SD remains unknown. The purpose of this study was to explore the protective effects of propofol on excessive autophagy and mitophagy in the hippocampus of rats after SD. METHODS: Adult male rats were intraperitoneally injected with 30 mg/kg of propofol after 96 hours of SD. Then we evaluated the effect of propofol on the cognitive function of sleep deprived rats by the Morris water maze. Transmission electron microscopy, Western blotting, PCR, immunohistochemistry, autophagy enhancer and autophagy inhibitor were used to study the effect of propofol on hippocampal neurons of rat with excessive autophagy and mitophagy. RESULTS: The behavioral experimental results of the Morris water maze showed that propofol improved the learning and memory ability of sleep-deprived rats. The expression of Beclin1, PINK1, parkin, p62, and LC3 protein increased significantly after sleep deprivation. While the intervention of propofol could significantly reduce the expression of these proteins, rapamycin treatment eliminated this effect. CONCLUSIONS: Our findings showed that propofol could reduce the impairment of learning and memory in sleep-deprived rats by inhibiting excessive autophagy and mitophagy in hippocampal neurons. This strategy may provide an application basis for the clinical use of propofol in patients with chronic insomnia.

Exogenous morphine inhibits the growth of human gastric tumor in vivo.

Morphine is commonly used to relieve severe pain that is often associated with cancer. Previous studies have found that morphine could affect cancer development; however, this effect is poorly understood. To further clarify the anti-cancer potential of morphine for the development of cancer in vivo, we observed how morphine affects the growth of human gastric tumor in a murine xenografting model and the expression of NF-κB and its downstream target genes (Bcl-2/Bax, cyclind1, and VEGF). The growth of the tumor was evaluated by its growth curves. The mRNA expression levels of NF-κB, Bcl-2/Bax, cyclind1, and VEGF were assessed by semi-quantitative polymerase chain reaction (qPCR). The protein expression of NF-κB, Bcl-2/Bax, cyclind1, and VEGF was detected by immunochemistry staining and western blot. Our data showed that morphine effectively inhibited the tumor growth in the nude mice. Morphine inhibits the expression of NF-κB, Bcl-2, cyclind1, and VEGF while enhancing the expression of Bax in the tumors. Furthermore, the anti-cancer effects of morphine could be reversed by naloxone. The mechanism might be associated with the action of opioid receptors that downregulate the expression of NF-κB leading to the regulation of the downstream target genes (Bcl-2/Bax, cylind1, and VEGF) in the tumors.

Fentanyl inhibits the progression of gastric cancer through the suppression of MMP-9 via the PI3K/Akt signaling pathway.

BACKGROUND: Fentanyl is a drug commonly used for perioperative and postoperative analgesia. Previous studies have confirmed that fentanyl can affect the progression of gastric cancer; however, this effect has not yet been elucidated. The purpose of our study was thus to investigate the role of fentanyl in gastric cancer and clarify its potential mechanisms. METHODS: A CCK-8 assay was used to determine the proliferation of MGC-803 cells, while Transwell assay and wound healing assay were used to determine the invasion and migration abilities, respectively. Apoptosis and the cell cycle were assessed by flow cytometry, and the ultrastructure of the cells was examined with a transmission electron microscope. The mRNA expression levels of serine-threonine protein kinase 1 (Akt-1), matrix metalloproteinase-9 (MMP-9), and death-associated protein kinase 1 (DAPK1) were evaluated by real-time (RT) quantitative PCR. The protein expression of p-Akt, MMP-9, and caspase-9 was detected by western blot analysis. To study the interaction of fentanyl with the phosphatidylinositol-3-kinase (PI3K)/Akt/MMP-9 pathway, PI3K inhibitor (LY294002) and MMP-9 inhibitor (SB-3CT) were used to treat the MGC-803 cells. RESULTS: Findings indicated that fentanyl inhibits the proliferation, invasion, and migration of MGC-803 cells. Specifically, fentanyl inhibits the expression of MMP-9 and enhances the expression of apoptosis-promoting factors such as caspase-9 and DAPK1 through the PI3K/Akt signaling pathway. Cell cycle arrest was observed in the G0/G1 phase. Furthermore, the inhibition of PI3K/Akt/MMP-9 by LY294002 and SB-3CT enhanced the anticancer effects of fentanyl. CONCLUSIONS: Fentanyl inhibits the proliferation, invasion and migration of gastric cancer cells by inhibiting the PI3K/Akt/MMP-9 pathway, which could be very useful for gastric cancer treatment.