As the chip of synthetic biology, enzymes play a vital role in the bio-manufacturing industry. The development of diverse functional enzymes can provide a rich toolbox for the development of synthetic biology. This article reports the construction of an artificial enzyme with the introduction of a non-natural cofactor. By introducing the 4-dimethylaminopyridine (DMAP) cofactor into the optimal protein skeleton <i>viai> covalent bonds based on a click-chemistry strategy, we successfully constructed a novel artificial enzyme with the DMAP cofactor as the catalytic center. The artificial enzyme successfully catalyzed an unnatural asymmetric Morita-Baylis- Hillman (MBH) reaction between cycloketenone and <i>pi>-nitrobenzaldehyde, with a conversion rate of 90% and enantioselectivity (<i>e.e.i>) of 38%. This study not only provides an effective strategy for the design of new artificial enzymes but also establishes a theoretical basis for the development of unnatural biocatalytic MBH reactions.
Biocatalysis ; 4-Aminopyridine/chemistry* ; Enzymes/metabolism* ; Coenzymes/chemistry* ; Benzaldehydes/chemistry* ; Protein Engineering/methods* ; Click Chemistry

Protein Engineering and Enzyme Engineering is a professional core course for life science-related majors in higher education, aiming to help students apply theoretical knowledge to engineering practice. The rapid development of biomanufacturing has placed new demands on the training of protein and enzyme engineers. However, due to the complexity and strong interdisciplinary nature of the course contents, traditional offline teaching modes have poor teaching performance and are unable to meet the era's demand for high-tech innovative talents in the field of biomanufacturing. To solve the above problems, we carried out the exploration and practice of blended teaching in Protein Engineering and Enzyme Engineering. We designed the teaching philosophy characterized by collaboration of online and offline learning, integration of pre-class preparation, in-class learning, and post-class review, linkage of online platforms, learning resources, teachers, and students, and enhancement <i>viai> scientific research, scientific contests, course experiments, production practice, and lesson learning. We developed a three-phase (pre-class, in-class, and post-class) teaching program and established a two-level (online-offline) teaching evaluation mechanism. This teaching mode upholds the student-oriented concept, strengthens the deep integration of theory and practice, and focuses on cultivating students' innovative thinking and practical ability. The practical results show that this teaching mode can improve the teaching quality of Protein Engineering and Enzyme Engineering, enhance students' scientific and technological innovation ability, and meet the national demand for biomanufacturing talents.
Protein Engineering ; Teaching ; Enzymes/genetics* ; Humans

Penicillin G acylases (PGAs) are industrially important enzymes primarily used for the synthesis of first- and second-generation cephalosporins or penicillins. This study aims to establish a high-efficiency biosynthetic system for cefradine on the purpose of significantly enhancing its catalytic efficiency in cefradine synthesis and developing its potentials for industrial application. In this study, we identified and engineered penicillin G acylase and obtained a highly active mutant <i>Ksi>PGA M7(M168F/F313G) for the synthesis of cefradine. The mutant achieved a conversion rate over 95% in the scaled-up reaction. To validate its industrial applicability, we immobilized both the wild-type and mutant enzymes and applied them in continuous flow reactions, which achieved a space-time yield of 2 800 g/(L·d). This study lays a foundation for the future applications of penicillin G acylases in the industrial synthesis of cefradine.
Penicillin Amidase/biosynthesis* ; Protein Engineering/methods* ; Cephradine/metabolism* ; Escherichia coli/metabolism* ; Enzymes, Immobilized/metabolism* ; Recombinant Proteins/biosynthesis*

OBJECTIVE: To explore the effect and mechanism of DNA methyltransferase 1 (DNMT1) knockout on the inhibition of acute myeloid leukemia (AML) by natural killer (NK) cells. METHODS: The peripheral blood NK cells of AML patients and controls were collected, and the mRNA and protein level of DNMT1 were measured by PCR and Western blot, respectively. The <i>DNMT1i> knockout mice were constructed to obtain NK^DNMT1-/- cells. The NK cells were stimulated with interleukin (IL)-12, IL-15, and IL-18 to construct memory NK cells, and then the interferon-γ (IFN-γ) levels were measured by ELISA. After co-culturing with memory NK cells and HL60 cells, the killing effect of NK^DNMT1-/- cells on HL60 cells was detected by LDH assay. Then, the HL60 cell apoptosis and NK cell NKG2D level were measured by flow cytometry. The perforin and granzyme B protein levels of NK cells were measured by Western blot. The AML model mice were constructed by injecting HL60 cells into the tail vein, meanwhile, memory NK cells were also injected, and then the mouse weights, CD33 positive rates, and survival time were detected. RESULTS: The mRNA and protein levels of DNMT1 in NK cells of AML patients were significantly higher than those in the control group (both <i>Pi> < 0.01), while the IFN-γ level induced by interleukin was significantly lower than that in the control group (<i>Pi> < 0.05). Compared with NK^DNMT1+/+ cells, the ability of NK^DNMT1-/- cells to secrete IFN-γ after interleukin stimulation was significantly increased (<i>Pi> < 0.05). The killing and apoptosis-inducing effects of NK^DNMT1-/- cells on HL60 cells were significantly stronger than those of NK^DNMT1+/+ cells (both <i>Pi> < 0.05). The NKG2D level and expression of perforin and granzyme B of NK^DNMT1-/- cells were significantly increased compared with NK^DNMT1+/+ cells (all <i>Pi> < 0.05). Compared with AML mice injected with NK^DNMT1+/+ cells, AML mice injected with NK^DNMT1-/- cells showed significantly increased body weight, decreased CD33 positive rate, and prolonged survival time (all <i>Pi> < 0.05). CONCLUSION Knocking out <i>DNMT1i> can enhance the inhibitory effect of NK cells on AML, which may be related to enhancing NK cell memory function.
Killer Cells, Natural/metabolism* ; Animals ; Leukemia, Myeloid, Acute ; Humans ; DNA (Cytosine-5-)-Methyltransferase 1 ; Mice ; Mice, Knockout ; HL-60 Cells ; Apoptosis ; Interferon-gamma/metabolism* ; Granzymes/metabolism* ; Perforin/metabolism* ; NK Cell Lectin-Like Receptor Subfamily K/metabolism*

BACKGROUND: Double-stranded RNA-specific adenosine deaminase 1 (ADAR1) binds to double-stranded RNA and catalyzes the deamination of adenosine (A) to inosine (I). The functional mechanism of ADAR1 in non-small cell lung cancer (NSCLC) remains incompletely understood. This study aimed to investigate the prognostic significance of ADAR1 in NSCLC and to elucidate its potential role in regulating tumor cell proliferation and migration. METHODS: Data from The Cancer Genome Atlas (TCGA) and cBioPortal were analyzed to assess the correlation between high ADAR1 expression and clinicopathological features as well as prognosis in lung cancer. We performed Western blot (WB), cell proliferation assays, Transwell invasion/migration assays, and nude mouse xenograft modeling to examine the phenotypic changes and molecular mechanisms induced by ADAR1 knockdown. Furthermore, the ADAR1 p150 overexpression model was utilized to validate the proposed mechanism. RESULTS: ADAR1 expression was significantly elevated in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) tissues compared with adjacent non-tumor tissues (LUAD: P=3.70×10-15, LUSC: P=0.016). High ADAR1 expression was associated with poor prognosis (LUAD: P=2.03×10-2, LUSC: P=2.81×10-2) and distant metastasis (P=0.003). Gene Set Enrichment Analysis (GSEA) indicated that elevated ADAR1 was associated with mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway activation, matrix metalloproteinase-9 (MMP-9) expression, and cell adhesion. ADAR1 and MMP-9 levels showed a strongly positive correlation (P=6.45×10-34) in 10 lung cancer cell lines, highest in H1581. Knockdown of ADAR1 in H1581 cells induced a rounded cellular morphology with reduced pseudopodia. Concomitantly, it suppressed cell proliferation, invasion, migration, and in vivo tumorigenesis. It also suppressed ERK phosphorylation and downregulated cellular Finkel-Biskis-Jinkins murine osteosarcoma viral oncogene homolog (c-FOS), MMP-9, N-cadherin, and Vimentin. Conversely, ADAR1 p150 overexpression in PC9 cells enhanced ERK phosphorylation and increased c-FOS and MMP-9 expression. CONCLUSIONS High ADAR1 expression is closely associated with poor prognosis and distant metastasis in NSCLC patients. Mechanistically, ADAR1 may promote proliferation, invasion, migration, and tumorigenesis in lung cancer cells via the ERK/c-FOS/MMP-9 axis.
Humans ; Lung Neoplasms/physiopathology* ; Adenosine Deaminase/genetics* ; Matrix Metalloproteinase 9/genetics* ; Cell Proliferation ; Carcinoma, Non-Small-Cell Lung/physiopathology* ; Cell Movement ; Animals ; Mice ; RNA-Binding Proteins/genetics* ; Female ; Male ; Cell Line, Tumor ; Proto-Oncogene Proteins c-fos/genetics* ; Middle Aged ; MAP Kinase Signaling System ; Gene Expression Regulation, Neoplastic ; Mice, Nude ; Extracellular Signal-Regulated MAP Kinases/genetics*

OBJECTIVE: To explore the mechanism of action of asperosaponin VI (AVI) in the treatment of rheumatoid arthritis (RA) and validate it in ex vivo experiments using network pharmacology and molecular docking methods. METHODS: The predicted targets of AVI were obtained from PharmMaper, UniProt and SwissTarget Prediction platforms, the disease targets were collected from Online Mendelian Inheritance in Man, Therapeutic Target Database and GeneCards databases, the intersection targets of AVI and RA were obtained from Venny 2.1.0, and the protein-protein interaction (PPI) network was obtained from STRING database, which was analyzed by Cytoscape software and screened to obtain the core targets. Cytoscape software was used to analyze PPI network and screen the core targets. Based on the Database for Annotation, Visualization and Integrated Discovery database, Gene Ontology functional and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were performed, and Cytoscape software was used to construct the "Disease-Pathway-Target-Drug" network, which was finally verified by molecular docking and animal experiments. RESULTS: Network pharmacological studies showed that AVI was able to modulate 289 targets, with 102 targets for the potential treatment of RA, with the core pathway being the AKT/PI3K signaling pathway, and the core targets being the epidermal growth factor receptor (EGFR) and matrix metalloproteinase 9 (MMP9). Molecular docking results showed that AVI could produce strong binding with both of the 2 core targets. In vitro cellular experiments showed that AVI reduced nitric oxide, prostaglandin E₂, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and IL-1 β levels (P<0.05) and inhibited cyclooxygenase-2, nitric oxide synthase, EGFR, MMP9, phosphorylated phosphoinositide 3-kinase (p-PI3K), and phosphorylated serine-threonine kinase (p-AKT) proteins (P<0.05). The results of in vivo studies showed that AVI improved RA score and foot swelling thickness and decreased TNF-α, IL-6, p-PI3K and p-AKT levels in RA rats (P<0.05). CONCLUSION AVI exerts anti-inflammatory and anti-RA effects which might be related to the EGFR/MMP9/AKT/PI3K pathway.
Saponins/chemistry* ; ErbB Receptors/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Signal Transduction/drug effects* ; Molecular Docking Simulation ; Animals ; Arthritis, Rheumatoid/drug therapy* ; Proto-Oncogene Proteins c-akt/metabolism* ; Matrix Metalloproteinase 9/metabolism* ; Protein Interaction Maps/drug effects* ; Humans ; Network Pharmacology ; Male ; Rats

Alzheimer's disease (AD) poses one of the most urgent medical challenges in the 21st century as it affects millions of people. Unfortunately, the etiopathogenesis of AD is not yet fully understood and the current pharmacotherapy options are somewhat limited. Here, we report a novel inhibitor, Compound 44, for targeting cholinesterases, amyloid-β (Aβ) aggregation, and glycogen synthase kinase 3β (GSK-3β) simultaneously with the aim of achieving symptomatic relief and disease modification in AD therapy. We found that Compound 44 had good inhibitory effects on all intended targets with IC₅₀s of submicromolar or better, significant neuroprotective effects in cell models, and beneficial improvement of cognitive deficits in the triple transgenic AD (3 × Tg AD) mouse model. Moreover, we showed that Compound 44 acts as an autophagy regulator by inducing nuclear translocation of transcription factor EB through GSK-3β inhibition, enhancing the biogenesis of lysosomes and elevating autophagic flux, thus ameliorating the amyloid burden and tauopathy, as well as mitigating the disease phenotype. Our results suggest that triple-target inhibition via Compound 44 could be a promising strategy that may lead to the development of effective therapeutic approaches for AD.
Animals ; Alzheimer Disease/genetics* ; Mice, Transgenic ; Glycogen Synthase Kinase 3 beta/metabolism* ; Disease Models, Animal ; Mice ; Amyloid beta-Peptides/metabolism* ; Cholinesterase Inhibitors/therapeutic use* ; Humans ; Autophagy/drug effects* ; Cognitive Dysfunction/pathology* ; Neuroprotective Agents/pharmacology*

Cerebral edema is characterized by fluid accumulation, and the glymphatic system (GS) plays a pivotal role in regulating fluid transport. Using the Tenecteplase system, magnesium salt of salvianolic acid B/ginsenoside Rg1 (SalB/Rg1) was injected intravenously into mice 4.5 h after middle cerebral artery occlusion and once every 24 h for the following 72 h. GS function was assessed by Evans blue imaging, near-infrared fluorescence region II (NIR-II) imaging, and magnetic resonance imaging (MRI). SalB/Rg1 had significant effects on reducing the infarct volume and hemorrhagic transformation score, improving neurobehavioral function, and protecting tissue structure, especially inhibiting cerebral edema. Meanwhile, the influx/efflux drainage of GS was enhanced by SalB/Rg1 according to NIR-II imaging and MRI. SalB/Rg1 inhibited matrix metalloproteinase-9 (MMP-9) activity, reduced cleaved β-dystroglycan (β-DG), and stabilized aquaporin-4 (AQP4) polarity, which was verified by colocalization with CD31. Our findings indicated that SalB/Rg1 treatment enhances GS function and attenuates cerebral edema, accompanying the regulation of the MMP9/β-DG/AQP4 pathway.
Animals ; Ginsenosides/administration & dosage* ; Brain Edema/etiology* ; Male ; Benzofurans/administration & dosage* ; Glymphatic System/diagnostic imaging* ; Mice ; Infarction, Middle Cerebral Artery/drug therapy* ; Aquaporin 4/metabolism* ; Disease Models, Animal ; Mice, Inbred C57BL ; Matrix Metalloproteinase 9/metabolism* ; Neuroprotective Agents/pharmacology* ; Depsides

Patients with severe pneumonia caused by novel coronavirus infection are often complicated with acute respiratory distress syndrome (ARDS), which has a high mortality. ARDS is characterized by diffuse alveolar damage, pulmonary edema, and hypoxemia. Mitochondria are prone to morphological and functional abnormalities under hypoxia and viral infection, which can lead to cell apoptosis and damage, severely impacting the disease progression. Mitochondria maintain homeostasis through fission and fusion. In ARDS, hypoxia leads to the phosphorylation of dynamin-related protein 1 (Drp1), triggering excessive mitochondrial fission and damaging the alveolar epithelial barrier. Animal experiments have shown that inhibiting this process can alleviate lung injury, providing a potential direction for treatment. The pathology of novel coronavirus infection-related ARDS is similar to that of typical ARDS but more severe. Viral infection and hypoxia disrupt the mitochondrial balance, causing fission and autophagy abnormalities, promoting oxidative stress and mitochondrial DNA (mtDNA) release, activating inflammasomes, inducing the expression of hypoxia-inducible factor-1α (HIF-1α), exacerbating viral infection, inflammation, and coagulation reactions, and resulting in multiple organ damage. Mechanical ventilation and glucocorticoids are commonly used in the treatment of novel coronavirus infection-related ARDS. Mechanical ventilation is likely to cause lung and diaphragm injuries and changes in mitochondrial dynamics, while the lung protective ventilation strategy can reduce the adverse effects. Glucocorticoids can regulate mitochondrial function and immune response and improve the patient's condition through multiple pathways. The mitochondrial dynamics imbalance in novel coronavirus infection-related ARDS is caused by hypoxia and viral proteins, leading to lung and multiple organ injuries. To clarify the pathophysiological mechanism of mitochondrial dynamics imbalance in novel coronavirus infection-related ARDS and explore effective strategies for regulating mitochondrial dynamics balance to treat this disease, so as to provide new treatment targets and methods for patients with novel coronavirus infection-related ARDS. The existing treatments have limitations. Future research needs to deeply study the mechanism of mitochondrial dysfunction, develop new therapies and regulatory strategies, and improve the treatment effect.
Humans ; Respiratory Distress Syndrome/etiology* ; COVID-19 ; Mitochondrial Dynamics ; Mitochondria/metabolism* ; DNA, Mitochondrial ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Dynamins ; SARS-CoV-2

BACKGROUND: Increasing evidence indicates that oxidative stress and interferon γ (IFNγ)-driven cellular immune responses are responsible for the pathogenesis of vitiligo. However, the connection between oxidative stress and the local production of IFNγ in early vitiligo remains unexplored. The aim of this study was to identify the mechanism underlying the production of IFNγ by mast cells and its impact on vitiligo pathogenesis. METHODS: Skin specimens from the central, marginal, and perilesional skin areas of active vitiligo lesions were collected to characterize changes of mast cells, CD8 + T cells, and IFNγ-producing cells. Cell supernatants from hydrogen peroxide (H 2 O 2 )-treated keratinocytes (KCs) were harvested to measure levels of soluble stem cell factor (sSCF) and matrix metalloproteinase (MMP)-9. A murine vitiligo model was established using Mas-related G protein-coupled receptor-B2 (MrgB2, mouse ortholog of human MrgX2) conditional knockout (MrgB2 -/- ) mice to investigate IFNγ production and inflammatory cell infiltrations in tail skin following the challenge with tyrosinase-related protein (Tyrp)-2 180 peptide. Potential interactions between the Tyrp-2 180 peptide and MrgX2 were predicted using molecular docking. The siRNAs targeting MrgX2 and the calcineurin inhibitor FK506 were also used to examine the signaling pathways involved in mast cell activation. RESULTS: IFNγ-producing mast cells were closely aligned with the recruitment of CD8 + T cells in the early phase of vitiligo skin. sSCF released by KCs through stress-enhanced MMP9-dependent proteolytic cleavage recruited mast cells into sites of inflamed skin (Perilesion vs . lesion, 13.00 ± 4.00/high-power fields [HPF] vs . 26.60 ± 5.72/HPF, P <0.05). Moreover, IFNγ-producing mast cells were also observed in mouse tail skin following challenge with Tyrp-2 180 (0 h vs . 48 h post-recall, 0/HPF vs . 3.80 ± 1.92/HPF, P <0.05). The IFNγ + mast cell and CD8 + T cell counts were lower in the skin of MrgB2 -/- mice than in those of wild-type mice (WT vs . KO 48 h post-recall, 4.20 ± 0.84/HPF vs . 0.80 ± 0.84/HPF, P <0.05). CONCLUSION Mast cells activated by MrgX2 serve as a local IFNγ producer that bridges between innate and adaptive immune responses against MCs in early vitiligo. Targeting MrgX2-mediated mast cell activation may represent a new strategy for treating vitiligo.
Vitiligo/metabolism* ; Mast Cells/immunology* ; Animals ; Interferon-gamma/metabolism* ; Mice ; Humans ; Melanocytes/metabolism* ; Receptors, G-Protein-Coupled/genetics* ; Mice, Knockout ; Mice, Inbred C57BL ; Male ; Female ; Matrix Metalloproteinase 9/metabolism* ; Stem Cell Factor/metabolism*