A chitosan-based antibacterial hydrogel with injectable and self-healing capabilities.

The presence of bacteria directly affects wound healing. Chitosan-based hydrogel biomaterials are a solution as they offer advantages for wound-healing applications due to their strong antimicrobial properties. Here, a double-cross-linking chitosan-based hydrogel with antibacterial, self-healing, and injectable properties is reported. Thiolated chitosan was successfully prepared, and the thiolated chitosan molecules were cross-linked by Ag-S coordination to form a supramolecular hydrogel. Subsequently, the amine groups in the thiolated chitosan covalently cross-linked with genipin to further promote hydrogel formation. In vitro experimental results indicate that hydrogel can release Ag+ over an extended time, achieving an antibacterial rate of over 99% against Escherichia coli and Staphylococcus aureus. Due to the reversible and dynamic feature of Ag-S coordination, an antibacterial hydrogel exhibited injectable and self-healing capabilities. Additionally, the hydrogel showed excellent biocompatibility and biodegradability. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-023-00211-z.

Switchable CO2-Responsive Janus Nanoparticle for Lipase Catalysis in Pickering Emulsion.

The use of convertible immobilized enzyme carriers is crucial for biphasic catalytic reactions conducted in Pickering emulsions. However, the intense mechanical forces during the conversion process lead to enzyme leakage, affecting the stability of the immobilized enzymes. In this study, a CO2-responsive switchable Janus (CrSJ) nanoparticle (NP) was developed using silica NP, with one side featuring aldehyde groups and the other side adsorbing N,N-dimethyldodecylamine. A switchable Pickering emulsion catalytic system for biphasic interface reactions was prepared by covalently immobilizing lipase onto the CrSJ NPs. The CO2-responsive nature of the CrSJ NPs allowed for rapid conversion of the Pickering emulsion, and covalent immobilization substantially reduced lipase leakage while enhancing the stability of the immobilization during the conversion process. Impressively, after repeated transformations, the Pickering emulsion still maintains its original structure. Following 10 consecutive cycles of esterification and hydrolysis reactions, the immobilized enzyme's activity remains at 77.7 and 79.5% of its initial activity, respectively. The Km of the CrSJ catalytic system showed no significant change compared to the free enzyme, while its Vmax values were 1.2 and 1.6 times that of the free enzyme in esterification and hydrolysis reactions, respectively.

Novel miR-490-3p/hnRNPA1-b/PKM2 axis mediates the Warburg effect and proliferation of colon cancer cells via the PI3K/AKT pathway.

BACKGROUND: Heterogeneous ribonucleoprotein A1 (hnRNPA1) has been reported to enhance the Warburg effect and promote colon cancer (CC) cell proliferation, but the role and mechanism of the miR-490-3p/hnRNPA1-b/PKM2 axis in CC have not yet been elucidated. AIM: To investigate the role and mechanism of a novel miR-490-3p/hnRNPA1-b/PKM2 axis in enhancing the Warburg effect and promoting CC cell proliferation through the PI3K/AKT pathway. METHODS: Paraffin-embedded pathological sections from 220 CC patients were collected and subjected to immunohistochemical analysis to determine the expression of hnRNPA1-b. The relationship between the expression values and the clinicopathological features of the patients was investigated. Differences in mRNA expression were analyzed using quantitative real-time polymerase chain reaction, while differences in protein expression were analyzed using western blot. Cell proliferation was evaluated using the cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays, and cell cycle and apoptosis were detected using flow cytometric assays. The targeted binding of miR-490-3p to hnRNPA1-b was validated using a dual luciferase reporter assay. The Warburg effect was evaluated by glucose uptake and lactic acid production assays. RESULTS: The expression of hnRNPA1-b was significantly increased in CC tissues and cells compared to normal controls (P < 0.05). Immunohistochemical results demonstrated significant variations in the expression of the hnRNPA1-b antigen in different stages of CC, including stage I, II-III, and IV. Furthermore, the clinicopathologic characterization revealed a significant correlation between hnRNPA1-b expression and clinical stage as well as T classification. HnRNPA1-b was found to enhance the Warburg effect through the PI3K/AKT pathway, thereby promoting proliferation of HCT116 and SW620 cells. However, the proliferation of HCT116 and SW620 cells was inhibited when miR-490-3p targeted and bound to hnRNPA1-b, effectively blocking the Warburg effect. CONCLUSION: These findings suggest that the novel miR-490-3p/hnRNPA1-b/PKM2 axis could provide a new strategy for the diagnosis and treatment of CC.

8-oxoguanine DNA glycosylase-1 may serve as biomarker of mechanical asphyxia.

AIM: To identify mtDNA and OGG1 as potential biomarker candidates for mechanical asphyxia. METHOD: The human tissues are divided into experimental group (hanging and strangulation) and control groups (hemorrhagic shock, brain injury group, and poisoning group). Detected the expression of OGG1 and integrity of mtDNA in cardiac tissue of each group. We used over-OGG1 vector and siRNA-OGG1 transfecting H9C2 cell line to observe the function of OGG1 in hypoxic cells. RESULTS: 1. mtDNA integrity decreased in the mechanical asphyxia group, OGG1 expression increased in mechanical asphyxia groups. They can be biomarkers for mechanical asphyxia. 2. OGG1 increased first and decreased in hypoxia-induced H9C2 cells. OGG1 upregulated the TFAM, NRF1, and Bcl2 in hypoxia-induced H9C2. OGG1 downregulated cleaved-Caspase3 in hypoxia-induced H9C2 cells. 3. In the normoxia condition, NAC maintained mtDNA integrity and decreased the mitochondrial membrane potential and amount of ATP. CONCLUSION: mtDNA integrity and OGG1 expression can be biomarkers for mechanical asphyxia. OGG1 can maintain mtDNA integrity and maintain the stability of the mitochondrial membrane.

A Dual-domain Engineered Antibody for Efficient HBV Suppression and Immune Responses Restoration.

Chronic hepatitis B (CHB) remains a major public health concern because of the inefficiency of currently approved therapies in clearing the hepatitis B surface antigen (HBsAg). Antibody-based regimens have demonstrated potency regarding virus neutralization and HBsAg clearance. However, high dosages or frequent dosing are required for virologic control. In this study, a dual-domain-engineered anti-hepatitis B virus (HBV) therapeutic antibody 73-DY is developed that exhibits significantly improved efficacy regarding both serum and intrahepatic viral clearance. In HBV-tolerant mice, administration of a single dose of 73-DY at 2 mg kg-1 is sufficient to reduce serum HBsAg by over 3 log10 IU mL-1 and suppress HBsAg to < 100 IU mL-1 for two weeks, demonstrating a dose-lowering advantage of at least tenfold. Furthermore, 10 mg kg-1 of 73-DY sustainably suppressed serum viral levels to undetectable levels for ≈ 2 weeks. Molecular analyses indicate that the improved efficacy exhibited by 73-DY is attributable to the synergy between fragment antigen binding (Fab) and fragment crystallizable (Fc) engineering, which conferred sustained viral suppression and robust viral eradication, respectively. Long-term immunotherapy with reverse chimeric 73-DY facilitated the restoration of anti-HBV immune responses. This study provides a foundation for the development of next-generation antibody-based CHB therapies.

Phosphorus deficiency alleviates iron limitation in Synechocystis cyanobacteria through direct PhoB-mediated gene regulation.

Iron and phosphorus are essential nutrients that exist at low concentrations in surface waters and may be co-limiting resources for phytoplankton growth. Here, we show that phosphorus deficiency increases the growth of iron-limited cyanobacteria (Synechocystis sp. PCC 6803) through a PhoB-mediated regulatory network. We find that PhoB, in addition to its well-recognized role in controlling phosphate homeostasis, also regulates key metabolic processes crucial for iron-limited cyanobacteria, including ROS detoxification and iron uptake. Transcript abundances of PhoB-targeted genes are enriched in samples from phosphorus-depleted seawater, and a conserved PhoB-binding site is widely present in the promoters of the target genes, suggesting that the PhoB-mediated regulation may be highly conserved. Our findings provide molecular insights into the responses of cyanobacteria to simultaneous iron/phosphorus nutrient limitation.

Discovery of novel ULK1 inhibitors through machine learning-guided virtual screening and biological evaluation.

Aim: Build a virtual screening model for ULK1 inhibitors based on artificial intelligence. Materials & methods: Build machine learning and deep learning classification models and combine molecular docking and biological evaluation to screen ULK1 inhibitors from 13 million compounds. And molecular dynamics was used to explore the binding mechanism of active compounds. Results & conclusion: Possibly due to less available training data, machine learning models significantly outperform deep learning models. Among them, the Naive Bayes model has the best performance. Through virtual screening, we obtained three inhibitors with IC50 of µM level and they all bind well to ULK1. This study provides an efficient virtual screening model and three promising compounds for the study of ULK1 inhibitors.

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Circulating Small Extracellular Vesicles Involved in Systemic Regulation Respond to RGC Degeneration in Glaucoma.

Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by progressive retinal ganglion cell (RGC) degeneration and vision loss. Since irreversible neurodegeneration occurs before diagnosable, early diagnosis and effective neuroprotection are critical for glaucoma management. Small extracellular vesicles (sEVs) are demonstrated to be potential novel biomarkers and therapeutics for a variety of diseases. In this study, it is found that intravitreal injection of circulating plasma-derived sEVs (PDEV) from glaucoma patients ameliorated retinal degeneration in chronic ocular hypertension (COH) mice. Moreover, it is found that PDEV-miR-29s are significantly upregulated in glaucoma patients and are associated with visual field defects in progressed glaucoma. Subsequently, in vivo and in vitro experiments are conducted to investigate the possible function of miR-29s in RGC pathophysiology. It is showed that the overexpression of miR-29b-3p effectively prevents RGC degeneration in COH mice and promotes the neuronal differentiation of human induced pluripotent stem cells (hiPSCs). Interestingly, engineered sEVs with sufficient miR-29b-3p delivery exhibit more effective RGC protection and neuronal differentiation efficiency. Thus, elevated PDEV-miR-29s may imply systemic regulation to prevent RGC degeneration in glaucoma patients. This study provides new insights into PDEV-based glaucoma diagnosis and therapeutic strategies for neurodegenerative diseases.