OBJECTIVE To investigate the apoptosis-inducing effect of esculetin （Esc） on acute myeloid leukemia （AML） HL-60 cells by regulating the protein kinase B （AKT）/S-phase kinase-associated protein 2 （SKP2）/MutT homolog 1 （MTH1） pathway. METHODS AML HL-60 cells were randomly divided into control group （routine culture）， Esc low-concentration group （L-Esc group， 25 μmol/L Esc）， Esc medium-concentration group （M-Esc group， 50 μmol/L Esc）， Esc high-concentration group （H-Esc group， 100 μmol/L Esc）， and high-concentration of Esc+ SC79 （AKT agonist） group （100 μmol/L Esc+5 μmol/L SC79）. Cell proliferation in each group was detected by MTT assay and colony formation assay. The level of reactive oxygen species （ROS） in cells was measured by using the CM-H2DCFDA fluorescent probe. Cell apoptosis was analyzed by flow cytometry. Western blot assay was performed to detect the expression levels of apoptosis-related proteins [B-cell lymphoma 2 （Bcl-2）， Bcl-2-associated X protein （Bax）， cleaved caspase-3]， AKT/SKP2/MTH1 pathway-related proteins （p-AKT， AKT， SKP2， MTH1）， along with the upstream and downstream proteins of AKT phosphatidylinositol 3-kinase （PI3K）， cyclin-dependent kinase inhibitor 1 （P21） and cyclin-dependent kinase inhibitor 1B （P27）. RESULTS Compared with control group， the cell viability， colony number， and the phosphorylation levels of AKT and PI3K proteins as well as protein expressions of SKP2， MTH1 and Bcl-2 were significantly decreased （P＜0.05）， while ROS level， apoptosis rate， and the expression levels of Bax， cleaved caspase-3， P21 and P27 proteins were significantly increased （P＜0.05）. Moreover， the effects of Esc exhibited concentration-dependence （P＜0.05）. Compared with H-Esc group， above indexes of high-concentration of Esc+ SC79 group were reversed significantly （P＜0.05）. CONCLUSIONS Esc may promote massive ROS production and induce activation of apoptosis in HL-60 cells by inhibiting the AKT/SKP2/MTH1 pathway， thus inhibiting the proliferation of HL-60 cells.

Objective To establish an oxidative stress mouse model of atopic dermatitis (AD) by applying 2,4-dinitrofluorobenzene (DNFB) to the back and post-auricular skin of KM mice, and to evaluate the regulatory role of the RAGE-NLRP3 axis (receptor for advanced glycation end products-NOD-like receptor family, pyrin domain containing 3 axis) in AD-related oxidative stress, thereby providing a potential therapeutic target for AD treatment. Methods Twenty SPF-grade female KM mice were randomly divided into a control group (Control group) and an experimental group (DNFB group), with 10 mice in each group. Mice in the Control group were treated with an acetone-olive oil vehicle (acetone: olive oil = 3:1) on their back and post-auricular skin. Mice in the DNFB group were treated with 0.5% DNFB (prepared by adding 0.5 g DNFB per 100 mL of acetone-olive oil vehicle) on the same areas, once daily for 14 consecutive days. The severity of skin lesions was scored on days 2, 4, 6, 9, 12, and 14 of treatment. On day 14, scratching behavior and ear thickness were evaluated. Ear swelling was evaluated on the final day by measuring bilateral ear thickness three times with a vernier caliper; the three measurements were averaged. HE staining was used to observe morphological and structural changes of cells in the back skin tissues. The mRNA and protein expression levels of RAGE (receptor for advanced glycation end products) in skin tissues were detected by quantitative real-time PCR, Western blot, and immunohistochemical staining. The mRNA expression levels of oxidative stress-related molecules, including NLRP3 (NOD-like receptor family, pyrin domain containing 3), caspase-1 (cysteine-dependent aspartate-specific protease 1), and IL-1β (Interleukin-1β), were detected by quantitative real-time PCR. Results On day 14, the back skin lesion scores of the Control group and DNFB group were (0.20±0.42) and (9.93±1.30) (P<0.000 1), respectively. Scratching behavior scores were (5.00±2.05) and (49.26±8.49) episodes, respectively (P<0.000 1), and ear thicknesses were (213.00±11.87) μm and (765.93±140.47) μm (P<0.000 1), respectively. The DNFB group exhibited marked skin dryness, desquamation, and thickening. HE staining results showed that skin inflammation was obvious in the DNFB group, consistent with the pathological features of AD. Quantitative real-time PCR and Western blot results showed that compared with the Control group, the mRNA expression level of RAGE in skin tissues of the DNFB group was significantly increased (P<0.05), and the protein expression level of RAGE was also significantly increased (P<0.01). Immunohistochemical staining results showed that compared with the Control group, skin tissue sections of the DNFB group exhibited thickened stratum corneum and fibrotic proliferation of fibroblasts in the interstitium under microscopic observation, with a significant increase in RAGE protein expression in the skin tissues (P<0.01). Quantitative real-time PCR results showed that the mRNA expression levels of NLRP3, caspase-1, and IL-1β in skin tissues of the DNFB group were all significantly increased (P<0.01). Conclusion The AD mouse oxidative stress model has been successfully established by topical DNFB application. RAGE may promote the development of AD by regulating the NLRP3 inflammasome and IL-1β release, forming an oxidative-inflammatory cascade, suggesting that it could be a potential therapeutic target for AD.

Objective: To develop a convenient, direct, and highly sensitive method for screening trace chemical additives in complex Chinese patent medicines, thereby addressing core technological bottlenecks in pharmaceutical analysis and quality control. Methods: A brush ionization probe device was independently designed and constructed, and an efficient detection method was established through systematic optimization of key parameters. Twenty-three Chinese patent medicine samples, representing 6 dosage forms (capsules, tablets, pills, granules, powders, and liquid preparations), were analyzed using 10 common chemical additives as target analytes. Results: All samples were successfully analyzed without complex pretreatment, and 5 chemical additives were detected in 7 Chinese patent medicines. The brush ionization probe device exhibited cost-effectiveness (~0.2 USD per probe), operational simplicity, rapid analysis (~10s per sample), high efficiency, and minimal reagent consumption (~10 μL per sample). Conclusion: This advancement is expected to provide an innovative scientific tool for improving the generality and convenience of on-site quality control, while promoting technological progress in disciplines such as pharmacology and traditional Chinese medicine.

Inteins are unique protein insertion sequences capable of self-excision, enabling the covalent ligation of flanking extein peptides via amide bond formation. This process proceeds spontaneously without requiring external enzymes, cofactors, or chemical reagents, granting inteins exceptional biocompatibility and traceless performance in protein engineering applications. Split inteins represent a specialized and versatile subclass whose splicing domains are encoded by two separate gene fragments rather than a single continuous open reading frame. These fragments, known as the N-terminal (IntN) and C-terminal (IntC) split inteins, associate through non-covalent interactions including hydrophobic forces, hydrogen bonds, and van der Waals forces to assemble into an active three-dimensional structure, which then drives efficient extein ligation and enables protein trans-splicing. Protein trans-splicing mediated by split inteins has become a cornerstone for traceless protein ligation owing to its high specificity and irreversibility, fundamentally reshaping strategies for protein modification, assembly, and functional regulation. Compared with traditional chemical ligation methods, split intein systems require no complex chemical derivatization of peptide fragments and can operate efficiently at micromolar concentrations under physiological conditions, thus avoiding structural and functional damage caused by organic reagents. In contrast to enzymatic ligation tools such as sortase, split inteins eliminate the need for additional enzymes or cofactors, simplifying reaction systems, reducing costs, and minimizing non-specific side products. These distinctive advantages render split inteins highly promising for applications in chemical biology, synthetic biology, and biopharmaceutical development. In recent years, deepened mechanistic understanding has established structure-guided rational design as the primary approach to overcoming key limitations of split inteins, including intrinsic aggregation propensity, strict extein sequence dependence, and limited splicing efficiency. Bioinformatic tools have been used to identify aggregation-prone regions in the IntN fragment, and site-directed mutagenesis of hydrophobic residues, relocation of split sites, or removal of misfolding-prone sequences has substantially reduced in vitro aggregation and improved soluble expression and assembly activity. Rational engineering of catalytic residues and adjacent flexible loops has relaxed strict amino acid preferences at extein junctions, enhancing sequence tolerance and reducing the risk of functional impairment in target proteins. Consensus design based on multiple sequence alignments has yielded ultra-fast splicing variants such as Cfa DnaE and Cat-TerL, which exhibit significantly accelerated kinetics and improved tolerance to denaturing conditions. Meanwhile, advances in structural biology have further clarified the conformational dynamics and catalytic mechanisms of splicing, supporting the precise design of high-performance intein modules. On this basis, electrostatic interaction tuning and metagenomic screening have yielded multiple mutually orthogonal split intein pairs, enabling selective multi-fragment protein ligation and providing new routes for the efficient synthesis of large multi-domain functional proteins. With these engineered split inteins offering continuously improved performance and expanded applicability, protein trans-splicing has been widely applied in numerous cutting-edge areas of protein research and biomedicine. In gene delivery, split intein-based systems overcome the packaging limit of adeno-associated viral vectors, enabling the accurate reconstitution of large therapeutic proteins and base editors in target cells, thereby enhancing the efficacy and scope of gene therapy for genetic diseases. In internal protein sequence editing, split inteins mediate precise sequence replacement and modification in flexible regions or loops of target proteins, without the need for complex multi-step ligation and protein refolding involved in traditional protein semisynthesis. In protein-protein interaction studies, intein-mediated splicing covalently captures transient and weak intracellular complexes, enabling sensitive, high-throughput interaction detection and drug screening. In synthetic biology, conditionally controllable splicing systems support the construction of diverse intracellular and cell-surface biological logic gates for the precise regulation of cellular behavior. In mechanistic biochemical research, split inteins enable photocatalytic proximity labeling and site-specific tagging, allowing the preparation of homogeneous protein samples carrying precise post-translational modifications such as ubiquitination and polyglutamylation for chromatin interactome analysis and epigenetic studies. Moreover, covalent trapping strategies using split inteins stabilize transient enzymatic intermediates, providing unprecedented insights into molecular mechanisms such as nucleosome ubiquitination that are difficult to elucidate using conventional methods. This review systematically summarizes key technological advances in split inteins over the past decade, highlighting engineering strategies, mechanistic insights, and the development of orthogonal components. It comprehensively surveys emerging applications at the frontiers of protein research, analyzes current core challenges, and proposes future directions, particularly emphasizing artificial intelligence-driven de novo design and novel splicing pathways to break existing technical bottlenecks. By enabling traceless, efficient, and versatile protein manipulation, split inteins continue to serve as indispensable tools that drive innovation in protein engineering and fundamental life science research.

Objective:To establish a mouse model of liver cancer resistant to PD-1 monoclonal antibody and analyze the changes in its metabolomics to explore the potential mechanism of drug resistance.Methods:BALB/c mice were randomly divided into control and treatment groups after being loaded with tumor,and a normal group was additionally set up.The normal and control groups were injected with saline,and the treatment group was injected with PD-1 monoclonal antibody,after which the mice in the treatment group were screened for drug resistant and response groups.Observed the drug-resistant situation,body mass,tumor growth and survival rate of mice in each group,calculate the spleen index.The pathological features of tumor tissues were observed by HE staining method.Serum metabolites were detected by non-targeted metabolomics.Finally,a bivariate Pearson correlation analysis was conducted between the differential serum metabolites and tumor size.Results:The tumor-bearing mouse model with PD-1 monoclonal antibody resistance was successfully established,and the drug resistance rate of the mice was 50％.Compared with the normal and response groups,mice in the resistant group showed an increase in body weight,a significant increase in tumor volume,a decrease in survival rate,and a significant increase in splenic index.There was less lymphocyte infiltration in the tumor tissue.Metabolomics analysis showed that the serum levels of glutamic acid and aspartic acid increased and malic acid decreased in the resistant mice compared with the response group,and these changes were closely related to the arginine biosynthesis pathway.Conclusions:The tumor-bearing mouse model with PD-1 monoclonal antibody resistance was successfully established.The changes in its peripheral serum metabolomics mainly involve arginine metabolism and the related changes of aspartate,malate and glutamate.

Objective:To investigate the value of 0.55 T MRI scanner using deep-learning (DL) reconstruction in evaluating pulmonary tumors.Methods:The study was a cross-sectional study. Sixty-one patients with pulmonary tumors on CT images were prospectively collected from May to September 2024 in Peking University First Hospital, including 37 males and 24 females, and aged 46?89 (68±9) years old. All patients underwent lung scan on a 0.55 T MRI, using diffusion weighted imaging(DWI) sequence with b-values of 0 and 800 s/mm 2. According to whether DL reconstruction was used and the number of acquisitions, they were divided into DWI-DL 5∶30 group (DL, number of averages=10, acquisition time=5 min 30 s),DWI-DL 3∶22 group (DL, number of averages=5, acquisition time=3 min 22 s), and DWI-C group (GRAPPA, number of averages=10, acquisition time=5 min 30 s). The obtained images were evaluated subjectively (Likert score) and objectively [signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)]. Meanwhile the apparent diffusion coefficient (ADC) value of the tumors was measured. Friedman nonparametric test was used for comparison among the three groups and Bonferroni method was used for pairwise comparison. Results:The subjective scores, SNR, and CNR were significantly different among DWI-DL 5∶30 group, DWI-DL 3∶22 group, and DWI-C group( χ 2=9.69,87.56,88.62, P=0.008,<0.001,<0.001). Bonferroni method results showed that the subjective scores, SNR, and CNR of DWI-DL 5∶30 group were higher than those of DWI-DL 3∶22 group and DWI-C group ( P<0.05); However, the subjective scores, SNR, and CNR did not significantly differ between DWI-DL 3∶22 group and DWI-C group ( P>0.05). The ADC values of the tumors were not significantly different among DWI-DL 5∶30 group, DWI-DL 3∶22 group, and DWI-C group (χ 2=5.95, P=0.510). Conclusion:The DWI reconstructed using DL has better or similar image quality to conventional DWI in evaluating pulmonary tumors and significantly reduces scanning time, which has certain clinical application value.

To construct a recombinant fowl adenovirus 4(FAdV-4)expressing the Cap protein of goose astrovirus genotype 2(GoAstV-2),the expression cassette of Cap gene was inserted into the natural 1 966 bp deletion region of the FAdV-4 genome in the infectious clone p15A-cm-FAdV4-HNJZ.The resulted recombinant plasmid p15A-cm-FAdV4-HNJZ-Cap/GoAstV-2 was linearized with restriction enzyme and transfected into chicken hepatoma cell line(LMH)to rescue the recombinant FAdV-4 expressing the Cap protein of GoAstV-2,rF Ad V4-Cap/GoAstV-2.After 15 passages in LMH cells,the recombinant rFAdV4-Cap/GoAstV-2 was identified by PCR using primers flanking the insertion site of the Cap gene expression cassette and using viral genome DNA extracted from rFAdV4-Cap/GoAstV-2 infected LMH cells as template.LMH cells were in-fected with 15th passage rFAdV4-Cap/GoAstV-2 and indirect immunofluorescence was performed with a polyclonal antibody against Cap protein as the primary antibody.Western blot was carried out with lysates of rFAdV4-Cap/GoAstV-2 infected LMH cells.The in vitro replication dynamic of the 15th passage of the rFAdV4-Cap/GoAstV-2 was also investigated in LMH cells.The results demonstrated that the Cap gene of GoAstV-2 was presented in the genome of the recombinant vi-rus rF AdV4-Cap/Go Ast V-2,and could be expressed stably.The prepared recombinant virus in this study will lay a foundation for developing inactivated bivalent vaccine candidate against co-in-fection of FAdV-4 and GoAstV-2 in goose.

AIM To prepare the sustained-release microspheres of ginsenosides.METHODS The sustained-release microspheres were prepared by SPG membrane emulsification technology with poly(lactic-co-glycolic acid)(PLGA)as a shell carrier.With PLGA concentration,feed rate and Span 60 concentration as influencing factors,comprehensive score for appearance,drug loading and encapsulation efficiency as an evaluation indice,the preparation process was optimized by response surface method.The morphology of sustained-release microspheres was observed,after which the particle size,drug loading and encapsulation efficiency were determined,and the in vitro drug release was investigated.RESULTS The optimal conditons were determined to be 45 s for agitation time of primary emulsion,74.68 mg/mL for PLGA concentration,11％for feed rate,and 4.18 mg/mL for Span 60 concentration,the comprehensive score was 74.98.The round sustained-release microspheres demonstrated the average particle size of 4.33 μm,drug loading of(8.24±0.13)％,and encapsulation efficiency of(74.94±1.17)％,respectively.At 336 h,ginsenosides Rg1,Rb1,Rb2 displayed the accumulative release rates of 84.12％,78.04％,65.88％,respectively.CONCLUSION This reasonable and feasible method can be used for the preparation of sustained-release microspheres of ginsenosides with good appearance and high drug loading,which can provide references for the preparation of other water-soluble drug microspheres and solution of microsphere collapse problem.

There is significant inter-individual variation of pharmacokinetics and pharmacody-namics in patients receiving tacrolimus(TAC)for an-ti-rejection therapy,which cause the rejection or toxic action.Based on results of therapeutic drug monitoring and pathophysiological index of trans-plant patients,the individualized dosing regimen can be designed and adjusted by using model in-formed precision dosing(MIPD).The patients'clini-cal outcome can be improved.In the consensus,the different methods of MIPD used for patients re-ceived TAC for anti-rejection therapy were intro-duced,which can be used for the designing and ad-justing doing regimen,predicting adverse drug reac-tion,improving medication adherence and econom-ics during therapy.

Objective:To establish a mouse model of liver cancer resistant to PD-1 monoclonal antibody and analyze the changes in its metabolomics to explore the potential mechanism of drug resistance.Methods:BALB/c mice were randomly divided into control and treatment groups after being loaded with tumor,and a normal group was additionally set up.The normal and control groups were injected with saline,and the treatment group was injected with PD-1 monoclonal antibody,after which the mice in the treatment group were screened for drug resistant and response groups.Observed the drug-resistant situation,body mass,tumor growth and survival rate of mice in each group,calculate the spleen index.The pathological features of tumor tissues were observed by HE staining method.Serum metabolites were detected by non-targeted metabolomics.Finally,a bivariate Pearson correlation analysis was conducted between the differential serum metabolites and tumor size.Results:The tumor-bearing mouse model with PD-1 monoclonal antibody resistance was successfully established,and the drug resistance rate of the mice was 50％.Compared with the normal and response groups,mice in the resistant group showed an increase in body weight,a significant increase in tumor volume,a decrease in survival rate,and a significant increase in splenic index.There was less lymphocyte infiltration in the tumor tissue.Metabolomics analysis showed that the serum levels of glutamic acid and aspartic acid increased and malic acid decreased in the resistant mice compared with the response group,and these changes were closely related to the arginine biosynthesis pathway.Conclusions:The tumor-bearing mouse model with PD-1 monoclonal antibody resistance was successfully established.The changes in its peripheral serum metabolomics mainly involve arginine metabolism and the related changes of aspartate,malate and glutamate.