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.

Tumors are the second leading cause of death worldwide. Exosomes are a type of extracellular vesicle secreted from multivesicular bodies, with particle sizes ranging from 40 to 160 nm. They regulate the tumor microenvironment, proliferation, and progression by transporting proteins, nucleic acids, and other biomolecules. Compared with other drug delivery systems, exosomes derived from different cells possess unique cellular tropism, enabling them to selectively target specific tissues and organs. This homing ability allows them to cross biological barriers that are otherwise difficult for conventional drug delivery systems to penetrate. Due to their biocompatibility and unique biological properties, exosomes can serve as drug delivery systems capable of loading various anti-tumor drugs. They can traverse biological barriers, evade immune responses, and specifically target tumor tissues, making them ideal carriers for anti-tumor therapeutics. This article systematically summarizes the methods for exosome isolation, including ultracentrifugation, ultrafiltration, size-exclusion chromatography (SEC), immunoaffinity capture, and microfluidics. However, these methods have certain limitations. A combination of multiple isolation techniques can improve isolation efficiency. For instance, combining ultrafiltration with SEC can achieve both high purity and high yield while reducing processing time. Exosome drug loading methods can be classified into post-loading and pre-loading approaches. Pre-loading is further categorized into active and passive loading. Active loading methods, including electroporation, sonication, extrusion, and freeze-thaw cycles, involve physical or chemical disruption of the exosome membrane to facilitate drug encapsulation. Passive loading relies on drug concentration gradients or hydrophobic interactions between drugs and exosomes for encapsulation. Pre-loading strategies also include genetic engineering and co-incubation methods. Additionally, we review approaches to enhance the targeting, retention, and permeability of exosomes. Genetic engineering and chemical modifications can improve their tumor-targeting capabilities. Magnetic fields can also be employed to promote the accumulation of exosomes at tumor sites. Retention time can be prolonged by inhibiting monocyte-mediated clearance or by combining exosomes with hydrogels. Engineered exosomes can also reshape the tumor microenvironment to enhance permeability. This review further discusses the current applications of exosomes in delivering various anti-tumor drugs. Specifically, exosomes can encapsulate chemotherapeutic agents such as paclitaxel to reduce side effects and increase drug concentration within tumor tissues. For instance, exosomes loaded with doxorubicin can mitigate cardiotoxicity and minimize adverse effects on healthy tissues. Furthermore, exosomes can encapsulate proteins to enhance protein stability and bioavailability or carry immunogenic cell death inducers for tumor vaccines. In addition to these applications, exosomes can deliver nucleic acids such as siRNA and miRNA to regulate gene expression, inhibit tumor proliferation, and suppress invasion. Beyond their therapeutic applications, exosomes also serve as tumor biomarkers for early cancer diagnosis. The detection of exosomal miRNA can improve the sensitivity and specificity of diagnosing prostate and pancreatic cancers. Despite their promising potential as drug delivery systems, challenges remain in the standardization and large-scale production of exosomes. This article explores the future development of engineered exosomes for targeted tumor therapy. Plant-derived exosomes hold potential due to their superior biocompatibility, lower toxicity, and abundant availability. Furthermore, the integration of exosomes with artificial intelligence may offer novel applications in diagnostics, therapeutics, and personalized medicine.

Objective: To understand the moderating effect of cohabitation with parents on the association between peer dating behavior and sexual behaviors among secondary vocational school students, so as to provide a scientific basis for preventing sexual behaviors among secondary vocational school students. Methods: From March to April 2021, an electronic questionnaire survey was conducted among 3 180 students from 6 vocational schools in Shanghai (urban, suburban, exurban) and Shaanxi (Shangluo, Ankang, Baoji) using cluster sampling. Spearman correlation analysis was used to investigate the relationship of cohabitation with parents, peer dating behavior and sexual behaviors among secondary vocational school students. Binary Logistic regression analysis was performed to investigate the role of cohabitation with parents on peer dating behavior and sexual behaviors among secondary vocational students. Results: There was a significant negative between cohabitation with parents and sexual ( r =-0.04); and there was a positive correlation between peer dating behavior and sexual behaviors ( r =0.24), as well as cohabitation with parents and peer dating behavior ( r =0.04)( P <0.05). Multivariable Logistic regression analysis showed an association between peer dating behavior and the occurrence of sexual behaviors ( OR=2.79-12.95, P <0.05). Cohabitation with parents played a moderating role in the association between peer dating behavior and sexual behaviors, and a signification interaction was found between cohabitation with parents and reporting that a small part or about half of their peers had dating behavior ( OR =0.48, P <0.05). Conclusions The more peers dating behavior are associated with a higher risk of sexual behaviors among secondary vocational school students, and cohabitation with parents can partly reduce this risk. School and family sexuality education for secondary vocational students should be strengthened to improve their interpersonal skills and decision-making, and ability to resist peer pressure, so as to reduce their risk of sexual behaviors.

Background/Aims: Endoscopic radiofrequency ablation (ERFA) is a treatment option for superficial esophageal squamous cell neoplasia (ESCN), with a relatively low risk of stenosis; however, the long-term outcomes remain unclear. We aimed to compare the long-term outcomes of patients with widespread superficial ESCN who underwent endoscopic submucosal dissection (ESD) or ERFA. Methods: We retrospectively analyzed the clinical data of patients with superficial ESCN who underwent ESD or ERFA between January 2015 and December 2021. The primary outcome measure was recurrence-free survival. Results: Ninety-two and 33 patients with superficial ESCN underwent ESD and ERFA, respectively. The en bloc, R0, and curative resection rates for ESD were 100.0%, 90.2%, and 76.1%, respectively. At 12 months, the complete response rate was comparable between the two groups (94.6% vs 90.9%, p=0.748). During a median follow-up of 66 months, recurrence-free survival was significantly longer in the ESD group than in the ERFA group (p=0.004), while no significant differences in overall survival (p=0.845) and disease-specific survival (p=0.494) were observed.Preoperative diagnosis of intramucosal cancer (adjusted hazard ratio, 5.55; vs high-grade intraepithelial neoplasia) was an independent predictor of recurrence. Significantly fewer patients in the ERFA group experienced stenosis compare to ESD group (15.2% vs 38.0%, p=0.016). Conclusions The risk of recurrence was higher for ERFA than ESD for ESCN but overall survival was not affected. The risk of esophageal stenosis was significantly lower for patients who underwent ERFA.

Background/Aims: Endoscopic radiofrequency ablation (ERFA) is a treatment option for superficial esophageal squamous cell neoplasia (ESCN), with a relatively low risk of stenosis; however, the long-term outcomes remain unclear. We aimed to compare the long-term outcomes of patients with widespread superficial ESCN who underwent endoscopic submucosal dissection (ESD) or ERFA. Methods: We retrospectively analyzed the clinical data of patients with superficial ESCN who underwent ESD or ERFA between January 2015 and December 2021. The primary outcome measure was recurrence-free survival. Results: Ninety-two and 33 patients with superficial ESCN underwent ESD and ERFA, respectively. The en bloc, R0, and curative resection rates for ESD were 100.0%, 90.2%, and 76.1%, respectively. At 12 months, the complete response rate was comparable between the two groups (94.6% vs 90.9%, p=0.748). During a median follow-up of 66 months, recurrence-free survival was significantly longer in the ESD group than in the ERFA group (p=0.004), while no significant differences in overall survival (p=0.845) and disease-specific survival (p=0.494) were observed.Preoperative diagnosis of intramucosal cancer (adjusted hazard ratio, 5.55; vs high-grade intraepithelial neoplasia) was an independent predictor of recurrence. Significantly fewer patients in the ERFA group experienced stenosis compare to ESD group (15.2% vs 38.0%, p=0.016). Conclusions The risk of recurrence was higher for ERFA than ESD for ESCN but overall survival was not affected. The risk of esophageal stenosis was significantly lower for patients who underwent ERFA.

Background/Aims: Endoscopic radiofrequency ablation (ERFA) is a treatment option for superficial esophageal squamous cell neoplasia (ESCN), with a relatively low risk of stenosis; however, the long-term outcomes remain unclear. We aimed to compare the long-term outcomes of patients with widespread superficial ESCN who underwent endoscopic submucosal dissection (ESD) or ERFA. Methods: We retrospectively analyzed the clinical data of patients with superficial ESCN who underwent ESD or ERFA between January 2015 and December 2021. The primary outcome measure was recurrence-free survival. Results: Ninety-two and 33 patients with superficial ESCN underwent ESD and ERFA, respectively. The en bloc, R0, and curative resection rates for ESD were 100.0%, 90.2%, and 76.1%, respectively. At 12 months, the complete response rate was comparable between the two groups (94.6% vs 90.9%, p=0.748). During a median follow-up of 66 months, recurrence-free survival was significantly longer in the ESD group than in the ERFA group (p=0.004), while no significant differences in overall survival (p=0.845) and disease-specific survival (p=0.494) were observed.Preoperative diagnosis of intramucosal cancer (adjusted hazard ratio, 5.55; vs high-grade intraepithelial neoplasia) was an independent predictor of recurrence. Significantly fewer patients in the ERFA group experienced stenosis compare to ESD group (15.2% vs 38.0%, p=0.016). Conclusions The risk of recurrence was higher for ERFA than ESD for ESCN but overall survival was not affected. The risk of esophageal stenosis was significantly lower for patients who underwent ERFA.

Objective:To analyze the clinical characteristics of children with head and neck rhabdomyosarcoma (RMS) and to summarize the mid-long term efficacy of Beijing Children′s Hospital Rhabdomyosarcoma 2006 (BCH-RMS-2006) regimen and China Children′s Cancer Group Rhabdomyosarcoma 2016 (CCCG-RMS-2016) regimen.Methods:A retrospective cohort study. Clinical data of 137 children with newly diagnosed head and neck RMS at Beijing Children′s Hospital, Capital Medical University from March 2013 to December 2021 were collected. Clinical characteristic of patients at disease onset and the therapeutic effects of patients treated with the BCH-RMS-2006 and CCCG-RMS-2016 regimens were compared. The treatments and outcomes of patients with recurrence were also summarized. Survival analysis was performed by Kaplan-Meier method, and Log-Rank test was used for comparison of survival rates between groups.Results:Among 137 patients, there were 80 males (58.4%) and 57 females (41.6%), the age of disease onset was 59 (34, 97) months. The primary site in the orbital, non-orbital non-parameningeal, and parameningeal area were 10 (7.3%), 47 (34.3%), and 80 (58.4%), respectively. Of all patients, 32 cases (23.4%) were treated with the BCH-RMS-2006 regimen and 105 (76.6%) cases were treated with the CCCG-RMS-2016 regimen. The follow-up time for the whole patients was 46 (20, 72) months, and the 5-year progression free survival (PFS) and overall survival (OS) rates for the whole children were (60.4±4.4)% and (69.3±4.0)%, respectively. The 5-year OS rate was higher in the CCCG-RMS-2016 group than in BCH-RMS-2006 group ((73.0±4.5)% vs. (56.6±4.4)%, χ2=4.57, P=0.029). For the parameningeal group, the 5-year OS rate was higher in the CCCG-RMS-2016 group (61 cases) than in BCH-RMS-2006 group (19 cases) ((57.3±7.6)% vs. (32.7±11.8)%, χ2=4.64, P=0.031). For the group with meningeal invasion risk factors, the 5-year OS rate was higher in the CCCG-RMS-2016 group (54 cases) than in BCH-RMS-2006 group (15 cases) ((57.7±7.7)% vs. (30.0±12.3)%, χ2=4.76, P=0.029). Among the 10 cases of orbital RMS, there was no recurrence. In the non-orbital non-parameningeal RMS group (47 cases), there were 13 (27.6%) recurrences, after re-treatment, 7 cases survived. In the parameningeal RMS group (80 cases), there were 40 (50.0%) recurrences, with only 7 cases surviving after re-treatment. Conclusions:The overall prognosis for patients with orbital and non-orbital non-parameningeal RMS is good. However, children with parameningeal RMS have a high recurrence rate, and the effectiveness of re-treatment after recurrence is poor. Compared with the BCH-RMS-2006 regimen, the CCCG-RMS-2016 regimen can improve the treatment efficacy of RMS in the meningeal region.

Background/Aims: Endoscopic radiofrequency ablation (ERFA) is a treatment option for superficial esophageal squamous cell neoplasia (ESCN), with a relatively low risk of stenosis; however, the long-term outcomes remain unclear. We aimed to compare the long-term outcomes of patients with widespread superficial ESCN who underwent endoscopic submucosal dissection (ESD) or ERFA. Methods: We retrospectively analyzed the clinical data of patients with superficial ESCN who underwent ESD or ERFA between January 2015 and December 2021. The primary outcome measure was recurrence-free survival. Results: Ninety-two and 33 patients with superficial ESCN underwent ESD and ERFA, respectively. The en bloc, R0, and curative resection rates for ESD were 100.0%, 90.2%, and 76.1%, respectively. At 12 months, the complete response rate was comparable between the two groups (94.6% vs 90.9%, p=0.748). During a median follow-up of 66 months, recurrence-free survival was significantly longer in the ESD group than in the ERFA group (p=0.004), while no significant differences in overall survival (p=0.845) and disease-specific survival (p=0.494) were observed.Preoperative diagnosis of intramucosal cancer (adjusted hazard ratio, 5.55; vs high-grade intraepithelial neoplasia) was an independent predictor of recurrence. Significantly fewer patients in the ERFA group experienced stenosis compare to ESD group (15.2% vs 38.0%, p=0.016). Conclusions The risk of recurrence was higher for ERFA than ESD for ESCN but overall survival was not affected. The risk of esophageal stenosis was significantly lower for patients who underwent ERFA.

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

OBJECTIVE: To investigate the effect of zedoarondiol on neovascularization of atherosclerotic (AS) plaque by exosomes experiment. METHODS: ApoE^-/- mice were fed with high-fat diet to establish AS model and treated with high- and low-dose (10, 5 mg/kg daily) of zedoarondiol, respectively. After 14 weeks, the expressions of anti-angiogenic protein thrombospondin 1 (THBS-1) and its receptor CD36 in plaques, as well as platelet activation rate and exosome-derived miR-let-7a were detected. Then, zedoarondiol was used to intervene in platelets in vitro, and miR-let-7a was detected in platelet-derived exosomes (Pexo). Finally, human umbilical vein endothelial cells (HUVECs) were transfected with miR-let-7a mimics and treated with Pexo to observe the effect of miR-let-7a in Pexo on tube formation. RESULTS: Animal experiments showed that after treating with zedoarondiol, the neovascularization density in plaques of AS mice was significantly reduced, THBS-1 and CD36 increased, the platelet activation rate was markedly reduced, and the miR-let-7a level in Pexo was reduced (P<0.01). In vitro experiments, the platelet activation rate and miR-let-7a levels in Pexo were significantly reduced after zedoarondiol's intervention. Cell experiments showed that after Pexo's intervention, the tube length increased, and the transfection of miR-let-7a minics further increased the tube length of cells, while reducing the expressions of THBS-1 and CD36. CONCLUSION Zedoarondiol has the effect of inhibiting neovascularization within plaque in AS mice, and its mechanism may be potentially related to inhibiting platelet activation and reducing the Pexo-derived miRNA-let-7a level.
Animals ; MicroRNAs/genetics* ; Exosomes/drug effects* ; Plaque, Atherosclerotic/genetics* ; Neovascularization, Pathologic/genetics* ; Human Umbilical Vein Endothelial Cells/metabolism* ; Humans ; Blood Platelets/drug effects* ; Apolipoproteins E/deficiency* ; Thrombospondin 1/metabolism* ; CD36 Antigens/metabolism* ; Platelet Activation/drug effects* ; Male ; Mice ; Mice, Inbred C57BL