ObjectiveThis study leverages structural data from antigen-antibody complexes of the influenza A virus neuraminidase (NA) protein to investigate the spatial recognition relationship between the antigenic epitopes and antibody paratopes. MethodsStructural data on NA protein antigen-antibody complexes were comprehensively collected from the SAbDab database, and processed to obtain the amino acid sequences and spatial distribution information on antigenic epitopes and corresponding antibody paratopes. Statistical analysis was conducted on the antibody sequences, frequency of use of genes, amino acid preferences, and the lengths of complementarity determining regions (CDR). Epitope hotspots for antibody binding were analyzed, and the spatial structural similarity of antibody paratopes was calculated and subjected to clustering, which allowed for a comprehensively exploration of the spatial recognition relationship between antigenic epitopes and antibodies. The specificity of antibodies targeting different antigenic epitope clusters was further validated through bio-layer interferometry (BLI) experiments. ResultsThe collected data revealed that the antigen-antibody complex structure data of influenza A virus NA protein in SAbDab database were mainly from H3N2, H7N9 and H1N1 subtypes. The hotspot regions of antigen epitopes were primarily located around the catalytic active site. The antibodies used for structural analysis were primarily derived from human and murine sources. Among murine antibodies, the most frequently used V-J gene combination was IGHV1-12*01/IGHJ2*01, while for human antibodies, the most common combination was IGHV1-69*01/IGHJ6*01. There were significant differences in the lengths and usage preferences of heavy chain CDR amino acids between antibodies that bind within the catalytic active site and those that bind to regions outside the catalytic active site. The results revealed that structurally similar antibodies could recognize the same epitopes, indicating a specific spatial recognition between antibody and antigen epitopes. Structural overlap in the binding regions was observed for antibodies with similar paratope structures, and the competitive binding of these antibodies to the epitope was confirmed through BLI experiments. ConclusionThe antigen epitopes of NA protein mainly ditributed around the catalytic active site and its surrounding loops. Spatial complementarity and electrostatic interactions play crucial roles in the recognition and binding of antibodies to antigenic epitopes in the catalytic region. There existed a spatial recognition relationship between antigens and antibodies that was independent of the uniqueness of antibody sequences, which means that antibodies with different sequences could potentially form similar local spatial structures and recognize the same epitopes.

Biomolecular condensates are formed through phase separation of biomacromolecules such as proteins and RNAs. These condensates exhibit liquid-like properties that can futher transition into more stable material states. They form complex internal structures via multivalent weak interactions, enabling precise spatiotemporal regulations. However, the use of inconsistent and non-standardized terminology has become increasingly problematic, hindering academic exchange and the dissemination of scientific knowledge. Therefore, it is necessary to discuss the terminology related to biomolecular condensates in order to clarify concepts, promote interdisciplinary cooperation, enhance research efficiency, and support the healthy development of this field.

Objective To investigate the effect and mechanism of the signal transducer and activator of transcription 3 (STAT3) inhibitor Stattic on the rejection of mouse heart allograft. Methods BALB/c mice (donors) were used to transplant skin onto C57BL/6 mice (recipients). Four weeks later, memory CD4⁺ T cells (CD4⁺Tm) were isolated from the recipient mice's spleens. Mixed lymphocyte reaction experiment was conducted with C57BL/6 mouse splenocytes and CD4⁺Tm, and the EdU method was used to detect the effect of Stattic on CD4⁺Tm cell proliferation. A C57BL/6 mouse heart transplant (HTx) model was constructed, and the experiment was divided into four groups: Non-HTx group, HTx group, Tm/HTx group, and Tm/HTx+Stattic group. The survival of heart allografts in mice was observed daily. Hematoxylin-eosin staining was used to observe the histopathology of the heart allografts. Real-time fluorescent quantitative polymerase chain reaction was used to detect the expression levels of interferon (IFN)-γ, interleukin (IL)-2, IL-10, and transforming growth factor-β1 (TGF-β1) messenger RNA (mRNA) in the heart allografts. Enzyme-linked immunosorbent assay was used to detect the levels of IFN-γ, IL-2, IL-10, and TGF-β1 in the serum. Flow cytometry was used to detect the levels of CD4⁺Tm (CD4⁺CD44⁺CD62L⁺) in splenic lymphocytes. And Western blotting was used to detect the expression levels of STAT3 and p-STAT3 proteins in the heart allografts. Results When the concentration of Stattic exceeded 2.5 μmol/L, it could inhibit the proliferation of CD4⁺Tm cells. Compared with the HTx group, the Tm/HTx group showed shorter survival time of heart grafts, more severe histopathological damage, increased serum IFN-γ and IL-2 levels, decreased IL-10 and TGF-β1 levels, increased relative expression of IFN-γ and IL-2 mRNA, decreased relative expression of IL-10 and TGF-β1 mRNA in the heart allografts, increased proportion of CD4⁺Tm in splenic lymphocytes, and increased p-STAT3/STAT3 ratio in the heart allografts (all P<0.05). Compared with the Tm/HTx group, the Tm/HTx+Stattic group showed longer survival time of heart grafts, less severe histopathological damage, decreased serum IFN-γ and IL-2 levels, increased IL-10 and TGF-β1 levels, decreased relative expression of IFN-γ and IL-2 mRNA, increased relative expression of IL-10 and TGF-β1 mRNA in the heart allografts, decreased proportion of CD4⁺Tm in splenic lymphocytes, and decreased p-STAT3/STAT3 ratio in the heart allografts (all P<0.05). Conclusions Stattic may prolong the survival time of mouse heart allografts, and its mechanism may be related to the inhibition of CD4⁺Tm- mediated acute rejection.

Aim To evaluate the effect of Pien Tze Huang(PTH)on influenza virus susceptibility in re-straint stress-induced H1N1 influenza susceptibility model in mice with emotional disorders and internal heat,guided by the theory of emotional pathogenesis.Methods Mice were infected with H1N1 influenza vi-rus following 18 h of restraint stress.The signs and weight changes of mice were recorded,and the morbid-ity of mice were analyzed.On the fourth day post viral infection,the lung tissue was collected.The pathologi-cal changes and inflammatory factors in lungs were de-tected by HE staining.The expression of NP was as-sessed by immunohistochemistry and Western blot.The level of lipid peroxidation end products was detected u-sing a commercial kit and western blot.Redox phos-pholipidomics was analyzed in lung tissue by HPLC-MS/MS.Results PTH significantly reduced the mor-tality of influenza-susceptible mice induced by emotion-al stress,inhibited the expression of NP and the re-lease of inflammatory factors,improved inflammation in lung tissue,and alleviated the accumulation of lipid peroxidation end products.Phospholipid oxidation a-nalysis revealed the elevated levels of oxidized phos-pholipid choline and phosphatidylethanolamine in lung tissue of influenza-susceptible mice,which were signif-icantly reduced by PTH administration.Conclusions PTH exhibits promising efficacy in ameliorating influ-enza virus susceptibility induced by internal heat,and its mechanism of action may be related to the regulation of phospholipid peroxidation.

Aim To explore the core target,key com-ponents and mechanism of Tibetan medicine Rhodiola crenulata in improving cerebral microcirculation based on literature research,network pharmacology,molecu-lar docking and experimental verification.Methods The chemical components of Rhodiola were collected through literature and database,and the potential tar-gets of Rhodiola crenulata were predicted by reverse pharmacophore matching.The related targets of cere-bral microcirculation disorder were obtained and targets were mapping with Rhodiola crenulata.PPI network was constructed and the core targets were screened.The regulatory network of"herb-component-target-dis-ease"was constructed and key components were screened.GO and KEGG enrichment analysis were conducted,and a"Core target-Pathway-Biological Process"network was constructed.Finally,molecular docking validation was carried out,and RT-qPCR and Western blot were used for animal experiments to fur-ther confirm the results of network pharmacology analy-sis.Results A total of 76 active components of Rhodiola crenulata were obtained and corresponding to 285 targets.Altogether 1074 related targets related to cerebral microcirculation disorder were obtained.A-mong them,there were 97 common targets and the main core targets were 6.The key components were 6.The results of molecular docking showed that the bind-ing activity of three key components to the core target was greater than that of the core target protein and its original ligand.The result of RT-qPCR and Western blot demonstrated that Tibetan medicine Rhodiola cre-nulata could significantly reduce the expression of core target CASP3 and AKT1(P＜0.01).Conclusions Tibetan medicine Rhodiola crenulata can improve the cerebral microcirculation disorder through multi compo-nents,multi targets and multi pathways.This study provides an experimental basis for clinical application of Tibetan medicine Rhodiola crenulata to treat cerebral microcirculation disorder.

Modern Chinese medicine studies have confirmed that the interaction between traditional Chinese medicine(TCM)and intestinal flora is the key to the treatment of diseases with tradi-tional Chinese medicine.This interplay includes such activities as:traditional Chinese medicine can be metabolized by intestinal flora into effective components with different biological activities from its precursors;TCM chemicals improve the composition of gut microbiota,consequently ameliorating its dysfunction as well as associated pathological conditions;and gut microbiota mediate the interactions between the multiple chemicals in TCM.There-fore,it becomes an important way to understand the modern sci-entific connotation of traditional Chinese medicine theory to study the pharmacological mechanism of the efficacy of traditional Chi-nese medicine by targeting Gut microbiota.

Aim To investigate the preventive and therapeutic effects of the mfat-1 gene therapy on exper-imental autoimmune encephalomyelitis in mice.Meth-ods mfat-1 gene therapy was used to render the host endogenous capability of producing ω-3 PUFAs,con-comitantly reduce the levels of ω-6 PUFAs,and change the proportion of ω-3/ω-6 PUFAs.Then,the levels of PUFAs in blood were analyzed by gas chromatography.The neurological deficits in mice were evaluated by neurological dysfunction score.HE staining and LFB staining of mouse spinal cord slices were used to ob-serve central nervous system inflammation infiltration and demyelinating lesions.Flow cytometry microsphere microarray technology was used to detect the content of cytokines in serum.Results The mfat-1 gene therapy could significantly raise the proportion of ω-3/ω-6 PU-FAs(P＜0.05),markedly delay the incubation period and peak period and reduce neurological dysfunction scores(P＜0.05),and improve inflammation and de-myelination of spinal cords(P＜0.05).It could also greatly increase the levels of IL-2,IFN-γ,IL-4 and IL-17 in serum(P＜0.05).Conclusion The pro-portion of ω-3/ω-6 PUFAs in blood circulation en-hanced by mfat-1 gene therapy can effectively prevent and treat experimental autoimmune encephalomyelitis in mice.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Objective To investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.

Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7％)and Enterococcus faecalis(41.5％).The strains were mainly isolated from urinary tract specimens(46.9％±2.6％),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6％).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1％and 1.3％,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7％in 2015 to 3.4％in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3％.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.