The initiation of adaptive immune responses relies on the precise recognition and interpretation of antigenic information. In this process, the specific binding of T cell receptors (TCRs) to peptide-major histocompatibility complex (pMHC) molecules represents one of the key molecular events in the initiation of adaptive immune responses. Accordingly, the structural features of TCR-pMHC complexes provide a fundamental basis for dissecting antigen recognition mechanisms and support rational vaccine design, therapeutic target discovery in TCR-based immunotherapy, and TCR identification and optimization. However, experimental determination of TCR-pMHC structures remains costly, time-consuming, and limited in coverage, making computational approaches essential for rapidly obtaining reliable structural information. Computational methods for predicting the structures of TCR-pMHC complexes have advanced rapidly in recent years, driven by progress in deep learning-based modeling frameworks and the increasing availability of structural and sequence resources. Despite these developments, most existing tools do not adequately distinguish the key structural and biophysical differences between MHC class I (MHC-I) and MHC class II (MHC-II) complexes during model construction. As a consequence, their predictive performance differs substantially between class I and class II complexes. In general, structural predictions for class I complexes outperform those for class II complexes. This discrepancy may be related to several fundamental differences between the two systems, including the architecture of the peptide-binding groove, the distribution of peptide lengths, and the properties of peptide flanking residues (PFRs). Compared with MHC-I molecules, MHC-II molecules usually bind longer antigenic peptides, which typically range from 13 to 25 amino acids in length. PFRs at both termini of these peptides participate in regulating the overall conformation of TCR-pMHC class II complexes and exert a pronounced effect on the geometric and physicochemical characteristics of the TCR-pMHC binding interface. Furthermore, within the TCR recognition interface, the complementarity-determining regions (CDRs) consist of segments that differ markedly in conformational behavior. They commonly include regions that are relatively rigid and structurally stable, together with highly flexible segments exhibiting substantial conformational plasticity. These rigidity-flexibility features constitute an essential structural basis enabling TCRs to recognize diverse peptide-MHC ligands and to accommodate conformational heterogeneity at the interface. However, many current modeling tools, in an effort to enforce global conformational stability or reduce structural noise, tend to over-constrain intrinsically flexible regions. Such oversimplification may lead to inappropriate rigidification of flexible CDR loops, resulting in local structural distortions, compromised interface geometry, or even complete modeling failure for specific complexes. Against this background, the review approaches the field from the perspective of computational differences between MHC-I and MHC-II complexes. We first systematically organize and summarize available resources related to TCRs and pMHCs, including structural datasets, sequence databases, prediction tools, and benchmarking studies. We then focus on five representative tools capable of predicting both class I and class II complexes—AlphaFold2, AlphaFold3, TCRmodel2, tFold-TCR, and TCR-pHLA_ModellerS. After excluding structures present in the training sets of these tools, we constructed a benchmark dataset comprising 25 class I and 10 class II TCR-pMHC complexes in the bound state and conducted a systematic evaluation using this dataset. We first employ widely used general evaluation metrics, including All-Atom Root Mean Square Deviation (All-Atom RMSD), Backbone RMSD, Template Modeling score (TM-score), and DockQ, to assess the global conformational accuracy and interface modeling quality of class I and class II complexes. For class II complexes, we propose for the first time a peptide flanking residue deviation index, including the PFRs-Deviation Index (PFRs-DI), N-PFR-Deviation Index (N-PFR-DI), and C-PFR-Deviation Index (C-PFR-DI), to quantitatively characterize conformational deviations in PFRs. In addition, we propose the CDR conformational consistency index (CCC) designed to qualitatively evaluate the ability of prediction tools to capture TCR CDR conformational flexibility. These metrics collectively assess a tool’s ability to model both overall conformation and critical functional regions, thereby addressing the limitations of existing evaluation criteria that overemphasize global structure while inadequately capturing modeling quality in key functional areas. This establishes a unified analytical framework for MHC-I and MHC-II complexes to guide data resource selection, modeling strategy formulation, and evaluation system development. The framework further advances computational modeling and provides crucial support for multi-scale analysis of TCR-pMHC recognition mechanisms and their biological functions.

The initiation of adaptive immune responses relies on the precise recognition and interpretation of antigenic information. In this process, the specific binding of T cell receptors (TCRs) to peptide-major histocompatibility complex (pMHC) molecules represents one of the key molecular events in the initiation of adaptive immune responses. Accordingly, the structural features of TCR-pMHC complexes provide a fundamental basis for dissecting antigen recognition mechanisms and support rational vaccine design, therapeutic target discovery in TCR-based immunotherapy, and TCR identification and optimization. However, experimental determination of TCR-pMHC structures remains costly, time-consuming, and limited in coverage, making computational approaches essential for rapidly obtaining reliable structural information. Computational methods for predicting the structures of TCR-pMHC complexes have advanced rapidly in recent years, driven by progress in deep learning-based modeling frameworks and the increasing availability of structural and sequence resources. Despite these developments, most existing tools do not adequately distinguish the key structural and biophysical differences between MHC class I (MHC-I) and MHC class II (MHC-II) complexes during model construction. As a consequence, their predictive performance differs substantially between class I and class II complexes. In general, structural predictions for class I complexes outperform those for class II complexes. This discrepancy may be related to several fundamental differences between the two systems, including the architecture of the peptide-binding groove, the distribution of peptide lengths, and the properties of peptide flanking residues (PFRs). Compared with MHC-I molecules, MHC-II molecules usually bind longer antigenic peptides, which typically range from 13 to 25 amino acids in length. PFRs at both termini of these peptides participate in regulating the overall conformation of TCR-pMHC class II complexes and exert a pronounced effect on the geometric and physicochemical characteristics of the TCR-pMHC binding interface. Furthermore, within the TCR recognition interface, the complementarity-determining regions (CDRs) consist of segments that differ markedly in conformational behavior. They commonly include regions that are relatively rigid and structurally stable, together with highly flexible segments exhibiting substantial conformational plasticity. These rigidity-flexibility features constitute an essential structural basis enabling TCRs to recognize diverse peptide-MHC ligands and to accommodate conformational heterogeneity at the interface. However, many current modeling tools, in an effort to enforce global conformational stability or reduce structural noise, tend to over-constrain intrinsically flexible regions. Such oversimplification may lead to inappropriate rigidification of flexible CDR loops, resulting in local structural distortions, compromised interface geometry, or even complete modeling failure for specific complexes. Against this background, the review approaches the field from the perspective of computational differences between MHC-I and MHC-II complexes. We first systematically organize and summarize available resources related to TCRs and pMHCs, including structural datasets, sequence databases, prediction tools, and benchmarking studies. We then focus on five representative tools capable of predicting both class I and class II complexes—AlphaFold2, AlphaFold3, TCRmodel2, tFold-TCR, and TCR-pHLA_ModellerS. After excluding structures present in the training sets of these tools, we constructed a benchmark dataset comprising 25 class I and 10 class II TCR-pMHC complexes in the bound state and conducted a systematic evaluation using this dataset. We first employ widely used general evaluation metrics, including All-Atom Root Mean Square Deviation (All-Atom RMSD), Backbone RMSD, Template Modeling score (TM-score), and DockQ, to assess the global conformational accuracy and interface modeling quality of class I and class II complexes. For class II complexes, we propose for the first time a peptide flanking residue deviation index, including the PFRs-Deviation Index (PFRs-DI), N-PFR-Deviation Index (N-PFR-DI), and C-PFR-Deviation Index (C-PFR-DI), to quantitatively characterize conformational deviations in PFRs. In addition, we propose the CDR conformational consistency index (CCC) designed to qualitatively evaluate the ability of prediction tools to capture TCR CDR conformational flexibility. These metrics collectively assess a tool’s ability to model both overall conformation and critical functional regions, thereby addressing the limitations of existing evaluation criteria that overemphasize global structure while inadequately capturing modeling quality in key functional areas. This establishes a unified analytical framework for MHC-I and MHC-II complexes to guide data resource selection, modeling strategy formulation, and evaluation system development. The framework further advances computational modeling and provides crucial support for multi-scale analysis of TCR-pMHC recognition mechanisms and their biological functions.

Plant-derived extracellular vesicles (PDEVs) are nanoscale extracellular vesicles secreted by plant cells, characterized by a lipid bilayer structure. These vesicles carry a variety of bioactive molecules, including proteins, nucleic acids, and lipids, and play essential roles in intercellular communication and physiological regulation in plants. Compared to animal-derived extracellular vesicles, PDEVs offer several advantages, such as a broad range of sources, high biocompatibility, low immunogenicity, and low production costs. Furthermore, PDEVs have demonstrated remarkable potential as natural nanocarriers for drug delivery, due to their ability to efficiently traverse biological barriers, such as the blood-brain barrier, making them promising candidates for drug delivery systems. This review systematically elaborates on the complex composition of PDEVs, which consists of lipids, proteins, and nucleic acids, the typical structural characteristics of their lipid bilayers ranging from 30 to 150 nm, and their versatile loading capabilities as drug carriers, efficiently encapsulating various types of therapeutic agents such as hydrophilic small molecules, hydrophobic drugs, nucleic acids, and proteins. We systematically summarize the recent advancements in strategies for enhancing the loading efficiency of PDEVs, which include methods such as co-incubation, ultrasound-assisted loading, electroporation, freeze-thaw cycles, and microfluidic technology. These techniques are evaluated based on their underlying principles, suitable drug types, and their respective advantages. In addition to loading strategies, we focus on the engineered approaches to achieve targeted delivery using PDEVs, such as genetic engineering modifications, chemical ligand conjugation, membrane fusion technology, and polyethylene glycol (PEG) modification. We discuss the mechanisms of these strategies in enhancing targeting efficiency, prolonging in vivo circulation time, and improving therapeutic efficacy. Further, this review highlights the application of PDEVs in various disease models, including tumor, skin inflammation, metabolic disorders, and neurodegenerative diseases, showcasing their therapeutic potential as multifunctional delivery platforms. The ability of PDEVs to encapsulate diverse therapeutic agents and target specific tissues or cells opens up new avenues for the treatment of complex diseases, offering advantages over conventional drug delivery systems. However, despite the promising applications of PDEVs, several challenges remain in their development and clinical translation. These challenges include variability in source materials, standardization of preparation processes, quality control, scalability of production, and the need for clinical validation. To overcome these obstacles, the integration of advanced technologies such as artificial intelligence-assisted design and multi-omics analysis is proposed as a way to facilitate the precise development of PDEVs. These emerging technologies hold the potential to further enhance the precision and effectiveness of plant-based drug delivery systems, ultimately advancing the field of precision medicine. In conclusion, the use of PDEVs as a platform for drug delivery represents a promising area of research with the potential to revolutionize therapeutic strategies. Their ability to encapsulate and deliver a wide variety of bioactive molecules, along with their inherent advantages in biocompatibility and versatility, makes them a valuable tool in the development of more efficient and targeted therapeutic interventions. Continued research and innovation in this field will pave the way for the clinical implementation of PDEVs in the treatment of various diseases, offering new hope for more effective and sustainable therapeutic options.

Objective:To explore the ultrasound changes,clinical efficacy and safety of ultrasound-guided compound betamethasone injection in the treatment of first metatarsophalangeal joint(MTP1)in acute gouty arthritis.Methods:This study was a prospective randomized controlled trial,71 patients diagnosed with MTP1 in acute gouty arthritis in Weifang People's Hospital from June 2022 to June 2024 were selected,they were divided into puncture treatment group of 36 cases and oral medication group of 35 cases according to the random number table method.The puncture treatment group was treated with ultrasound-guided compound betamethasone injection,and the oral medication group was treated with etocoxib combined with colchicine.Visual Analogue Scale(VAS),inflammatory indicators[erythrocyte sedimentation rate(ESR),C-reactive protein(CRP)],and semi-quantitative scores of musculoskeletal ultrasound of the two groups were compared,and the medication safety of the two groups was observed.Result:1,3 and 7 days after treatment,VAS score in the puncture treatment group decreased significantly compared with that in the oral medication group(P＜0.05).7 days after treatment,ESR and CRP in the puncture treatment group decreased more significantly,and semi-quantitative scores of musculoskeletal ultrasound showed that the improvement of joint effusion,synovial hyperplasia and blood flow signal was better than that in the oral medication group(P＜0.05).All 36 cases of puncture were successful at the first attempt without complications.Conclusion:Ultrasound-guided compound betamethasone injection in the treatment of MTP1 in acute gouty arthritis has a high success rate,it can rapidly reduce inflammation,relieve pain,restore joint function,and is safe to operate,it can be used as an effective treatment option.

Aim To investigate the protective effect of liraglutide(LIRA)on acetaminophen(APAP)-in-duced hepatotoxicity at the in vivo level and to reveal the underlying mechanism.Methods Forty SPF grade male C57BL/6J mice were randomly divided into the Control,LIRA(200 μg·kg-1),APAP(500 mg·kg-1),LIRA+APAP,LIRA+APAP+3-methylade-nine(3-MA,30 mg·kg-1)groups,with eight mice in each group.The mice were administered for three con-secutive days,and the materials were taken after 24 h.The general condition and body weight of mice in each group were recorded,and liver morphology was ob-served.Serum ALT and AST levels,as well as SOD ac-tivity,MDA,and GSH content in liver homogenates,were measured using biochemical assay kits.The levels of inflammatory cytokines IL-6,TNF-α,and IL-1β in serum were detected by ELISA.Liver pathological changes were assessed by HE staining,while mitochon-drial and autophagosome structures in liver tissues were observed using transmission electron microscopy.The number of PCNA-positive cells in liver tissues was e-valuated using immunohistochemical staining.The pro-tein expression levels of LC3Ⅱ,p62,Bax,Bcl-2,PC-NA,and CyclinD1 in liver tissues were determined by Western blot.Results LIRA pretreatment can im-prove the general condition of mice with acetamino-phen-induced liver injury(AILI),reduce serum ALT and AST levels,and effectively ameliorate the appear-ance and morphology of the liver as well as the patho-logical damage to liver tissue.Simultaneously,the lev-els of inflammatory cytokines IL-6,TNF-α,and IL-1βare significantly decreased;SOD activity and GSH con-tent are significantly increased,while MDA content is significantly reduced.Transmission electron microsco-py observations reveal the presence of numerous auto-phagosomes in the cytoplasm of liver tissue.Immuno-histochemical staining results indicate a significant in-crease in the number of PCNA-positive cells.Further-more,the expression of LC3Ⅱ,Bcl-2,PCNA,and Cy-clinD1 proteins in liver tissue is significantly upregulat-ed,while the expression of p62 and Bax proteins is significantly downregulated.However,after interven-tion with the autophagy inhibitor 3-MA,the aforemen-tioned protective effects of LIRA are significantly.Conclusions LIRA pretreatment can significantly im-prove liver injury in AILI mice.Its protective mecha-nism may be related to enhancing autophagy in hepato-cytes,thereby reducing oxidative stress,inflammatory response and apoptosis in liver of AILI mice.

Aim To investigate the protective effects of methyl rosmarinate(MR)on myocardial injury in-duced by high-altitude hypoxia and explore its underly-ing mechanisms.Methods BALB/c mice were ran-domly divided into a control group,a model group,and low-,medium-,and high-dose MR groups(25,50,and 75 mg·kg-1,respectively).Except for the control group,all other groups were exposed to a hypobaric hypoxia chamber and administered MR via intraperitoneal injection daily for three days.After the experiment,myocardial tissues were collected for he-matoxylin and eosin(HE)staining to observe morpho-logical changes.Levels of malondialdehyde(MDA),glutathione(GSH),and superoxide dismutase(SOD)were measured to evaluate the anti-myocardial injury activity of MR.Network pharmacology was employed to predict drug-disease interaction targets,construct a protein-protein interaction(PPI)network,and identify core targets.Functional enrichment analysis was car-ried out using Gene Ontology(GO)and Kyoto Ency-clopedia of Genes and Genomes(KEGG)pathways.Molecular docking was used to verify the binding affini-ty of MR to core targets,and Western blot was conduc-ted to detect the expression of related proteins.Results MR significantly alleviated myocardial injury caused by high-altitude hypoxia.Network pharmacology analy-sis identified EGFR,Bcl-2,STAT3,MMP9,ESR1,and MTOR as key targets.Molecular docking con-firmed strong binding between MR and these core tar-gets.Western blot results demonstrated that MR im-proved myocardial injury by regulating the expression of STAT3,Bax,and Bcl-2 proteins.Conclusion MR may exert its protective effects on high-altitude hypoxi-a-induced myocardial injury through a multi-target mechanism.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

High altitude heart disease(HAHD)is a chronic mountain sickness in which the body is exposed to high altitude(＞2 500 m)hypobaric hypoxia environment for a long time.HAHD has high morbidity and poor prognosis,and pulmonary hypertension is the main causative mechanism for its develop-ment.The phosphodiesterase-5 inhibitor sildenafil has become a hot drug for the treatment of pulmonary hypertension.This paper reviews the progress of HAHD and discusses the mechanism of action and effectiveness of sildenafil in the treatment of HAHD,with a view to providing a basis for the treatment of HAHD with sildenafil.

Objective To observe the effects of LINC01915 on the proliferation,migration and invasion of human colorectal cancer cells,and to explore its possible regulatory mechanism.Methods The colorectal cancer cell lines of SW620,SW480,LOVO,HCT116 and the normal colorectal cell line of NCM460 were selected,and the expression of LINC01915 was detected by RT-qPCR.HCT116 cell line with the highest expression of LINC01915 was taken and divided into the upregulation group,the downregulation group,the upregulation control group,the downregulation control group and the blank group.The transfection efficiency of each group was detected by fluorescence microscope;RT-qPCR was used to detect the expression of LINC01915 in each group;methyl thiazolyl tetrazolium(MTT)assay was used to detect the proliferative activity in each group;scratch wound healing assay and Transwell assay were used to detect the migration and invasion activities in each group;RT-qPCR was used to detect the expression of miR-92a-3p and mRNA expression of large tumor suppressor homolog 2(LATS2),transcription factor 21(TCF21)and Kruppel like factor 4(KLF4);and Western blot was used to detect the expression of LATS2,TCF21,and KLF4 proteins.Dual-fluorescein reporter assay was used to verify the targeting relationship between LINC01915 and miR-92a-3p.Results The expression of LINC01915 in various human colorectal cancer cell lines were lower than that in the NCM460 cell(P<0.05),and the highest LINC01915 expression in human colorectal cancer cell lines was observed in HCT116(P<0.05).The transfection efficiency of cells in each transfection group was high.Compared with the blank group and the upregulation control group,the expression of LINC01915,and mRNA and protein expression of LATS2,TCF21,and KLF4 in the upregulation group increased(P<0.05),and the A value,scratch healing rate,number of invasive cells and miR-92a-3p expression decreased(P<0.05).Compared with the blank group and the downregulation control group,the expression of LINC01915,and mRNA and protein expression of LATS2,TCF21,and KLF4 in the downregulation group decreased(P<0.05),and the A value,scratch healing rate,number of invasive cells and miR-92a-3p expression increased(P<0.05).LINC01915 had binding sites with miR-92a-3p,and compared with the miR-NC group,the miR-92a-3p mimics group showed a decrease in the luciferase activity of WT-LINC01915(P<0.05).Conclusion The expression of LINC01915 in the human colorectal cancer cell lines decreases,and upregulation of LINC01915 expression can inhibit cell proliferation,migration,and invasion,which may be related to the up-regulation of the expression of LATS2,TCF21 and KLF4 by inhibiting miR-92a-3p.

Objective:We summarize the clinical characteristics of surgeries in which the thyroid lobe is used as a transfer flap to treat early pharyngeal fistula following total laryngectomy.We also provide useful data for improving the diagnosis and management of this condition.Methods:Retrospective analysis was conducted on data from 8 patients with pharyngocutaneous fistulas after total laryngectomy for laryn-geal and pharyngeal cancer patients admitted to Hunan Provincial People's Hospital(The First Hospital Affiliated to Hunan Normal University)between October 2016 and October 2023.The surgeons performed a double-layer repair technique that included local inversion and a purse-string suture of the fistula using the thyroid lobe as a transfer flap.Clinical data were collected to analyze postoperative outcomes.Results:All eight patients experienced successful pharyngeal fistula repair.Postoperatively,these patients were managed with nasogastric tube feed-ing,liquid diet,and prophylactic antibiotics to prevent infection.After 10 days,their diet was changed to oral liquids,and their nasogastric tubes were removed.All patients were discharged after complete recovery.Conclusions:Use of the thyroid lobe as a transfer flap in a double-layer repair technique involving local inversion of the fistula is an effective method for repairing early pharyngeal fistula after total laryngectomy.This approach offers several advantages,including ease of flap harvesting,shortened operation time,reduced patient discom-fort,high transfer flap survival rate,and rapid postoperative recovery.The clinical efficacy of this technique is well-supported,making it a re-liable option for the management of early pharyngeal leaks.