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.

The conversion of carbon dioxide into high value-added energy has become a research hotspot.In this study,by using Ti3AlC2 and CuCl2·2H2O as precursors,accordion-like two-dimensional Cu0/Cu2+-Ti3C2Tx catalysts modified with Cu0 nanoparticles and Cu2+ self-intercalation were successfully prepared for electrocatalytic reduction of CO2.The performance of the material was tested,and the results showed that in a CO2-saturated 0.5 mol/L KHCO3 electrolyte solution,compared with the original Ti3AlC2,the initial potential of the electrocatalytic conversion of CO2 to C2H4 over Cu0/Cu2+-Ti3C2Tx catalyst decreased from ?0.65 V(vs RHE)to?0.01 V(vs RHE).The maximum current density increased from 0.19 mA/cm2 to 2.5 mA/cm2,the double layer capacitance(Cdl)value increased from 2.61 mF/cm2 to 55.06 mF/cm2.The material showed higher catalytic activity and faster electron transfer rate(Charge transfer resistance(Rct)value was only 16.9 Ω).Moreover,the material showed high electrochemical active area and excellent stability.This research provided a promising method for designing and preparing elcetrocatalytic reduction(ECR)catalysts in the future.

Background: Genetic defects in the human thyroid-stimulating hormone (TSH) receptor (TSHR) gene can cause congenital hypothyroidism (CH). However, the biological functions and comprehensive genotype–phenotype relationships for most TSHR variants associated with CH remain unexplored. We aimed to identify TSHR variants in Chinese patients with CH, analyze the functions of the variants, and explore the relationships between TSHR genotypes and clinical phenotypes. Methods: In total, 367 patients with CH were recruited for TSHR variant screening using whole-exome sequencing. The effects of the variants were evaluated by in-silico programs such as SIFT and polyphen2. Furthermore, these variants were transfected into 293T cells to detect their Gs/cyclic AMP and Gq/11 signaling activity. Results: Among the 367 patients with CH, 17 TSHR variants, including three novel variants, were identified in 45 patients, and 18 patients carried biallelic TSHR variants. In vitro experiments showed that 10 variants were associated with Gs/cyclic AMP and Gq/11 signaling pathway impairment to varying degrees. Patients with TSHR biallelic variants had lower serum TSH levels and higher free triiodothyronine and thyroxine levels at diagnosis than those with DUOX2 biallelic variants. Conclusions We found a high frequency of TSHR variants in Chinese patients with CH (12.3%), and 4.9% of cases were caused by TSHR biallelic variants. Ten variants were identified as loss-of-function variants. The data suggest that the clinical phenotype of CH patients caused by TSHR biallelic variants is relatively mild. Our study expands the TSHR variant spectrum and provides further evidence for the elucidation of the genetic etiology of CH.

Objective To investigate the therapeutic effect and mechanism of paeoniflorin(PAE)on thrombosis angiitis obliterans(TAO)in rats.Methods TAO rat model was established by sodium laurate injection.Rats were randomly divided into sham operation group(intraperitoneal injection of 0.9％NaCl),model group(intraperitoneal injection of 0.9％NaCl),experimental-L,-H groups(intraperitoneal injection of PAE 5,20 mg·kg-1·d-1),experimental-H+agonist group(intraperitoneal injection of 20 mg·kg-1·d-1 PAE+caudal vein injection of 10 ng·mL-1·kg 1·d-1 740 Y-P).Thrombin time(TT)was measured by magnetic bead coagulation;the levels of interleukin(IL)-1 β and endothelin 1(ET-1)were detected by enzyme-linked immunosorbent assay kit;the expression levels of phosphatidylinositol 3-kinase(PI3K),phosphorylated-PI3K(p-PI3 K),protein kinase B(AKT),p-AKT,nuclear factor(NF)-κB p65,p-NF-κB p65 were detected by Western blotting.Results The TT of sham operation group,model group,experimental-L,-H groups and experimental-H+agonist group were(14.88±1.32),(10.02±0.95),(12.65±1.22),(14.70±1.36)and(10.64±1.21)s;IL-1β were(154.23±13.45),(356.69±31.17),(268.62±23.58),(199.64±20.87)and(337.48±31.46)pg·mL-1;ET-1 were(6.78±0.68),(14.43±1.14),(11.23±1.07),(8.20±0.81)and(13.33±1.27)pg·mL-1;p-PI3K/PI3K were 0.36±0.04,0.76±0.07,0.59±0.05,0.44±0.04 and 0.69±0.07;p-AKT/AKT were 0.52±0.05,0.90±0.09,0.74±0.08,0.61±0.06 and 0.86±0.08;p-NF-κB p65/NF-κB p65 were 0.28±0.03,0.95±0.04,0.69±0.07,0.35±0.05 and 0.87±0.08,respectively.There were statistically significant differences between model group and sham operation group(all P＜0.05);the above indexes in experimental-L group and experimental-H group were significantly different from those in medel group(all P＜0.05);the above indexes in experimental-H+agonist group were significantly different from those in experimental-H group(all P＜0.05).Conclusion PAE may improve disease progression in TAO rats by inhibiting the PI3K/AKT/NF-κB signaling pathway.

Fragment with some anti-pancreatic cancer activity was identified by screening our internal chemical library. Eighteen compounds in 4 classes were synthesized by systematic modification and their anti-pancreatic cancer activity were evaluated. Ⅱ-1 (IC₅₀ = 6.40 ± 0.34 μmol·L^-1) and Ⅱ-2 (IC₅₀ = 7.15 ± 0.51 μmol·L^-1) exhibited outstanding activity. Subsequently, the anti-migration ability and invasion ability of Ⅱ-1 was evaluated by wound healing assay and invasion assay, Ⅱ-1 exhibited good anti-migration ability and outstanding anti-invasion ability. Using molecular docking technology and molecular dynamics simulation technology, the potential target was locked on bispecific tyrosine phosphorylation regulates kinase 1A (DYRK1A). By enzyme activity testing, the inhibitory capacity of Ⅱ-1 and Ⅱ-2 was 48% and 32%, respectively.

Objective To investigate the value of the volume percentage of solid component in differential diagnosis of stage Ⅰ lung adenocarcinoma subtypes,and to predict the optimal critical CT value of solid component.Methods A total of 962 nodules with sur-gical pathological findings confirmed as adenocarcinoma in situ(AIS)or pulmonary adenocarcinoma and manifested as subsolid nod-ules on thin-section CT were analyzed retrospectively,and divided the lesions into:(1)AIS(n=350)or pulmonary adenocarcinoma(n=612)groups;and(2)minimally invasive adenocarcinoma(MIA)(n=213)or invasive adenocarcinoma(IAC)(n=399)groups based on pathological findings.The volume percentage of solid components within pulmonary nodules was measured via CT density histogram analysis at different thresholds,the diagnostic efficacy of different thresholds was analyzed and the optimal critical CT val-ues of solid component was found.Results In the AIS versus pulmonary adenocarcinoma groups,age,mass,and volume percentage of solid component were statistically significant(P＜0.001);the CT threshold of-350 HU had the highest diagnostic efficacy[area under the curve(AUC)0.859,accuracy 81.69％,sensitivity 85.60％,and specificity 74.86％,respetively],and the critical value of volume percentage of solid component determined under this threshold was 8.3％.In the MIA versus IAC groups,age(P=0.017),mass(P＜0.001),and volume percentage of solid component(P＜0.001)were statistically significant;the CT threshold of-350 HU had the highest diagnostic efficacy(AUC 0.857,accuracy 78.27％,sensitivity 82.91％,and specificity 69.48％,respectively),and the critical value of volume percentage of solid component determined under this threshold was 16.9％.Conclusion The volume percentage of solid component measured based on CT density histogram analysis may be helpful in the differential diagnosis of early stage lung ade-nocarcinoma subtypes.

Objective To investigate the risk factors for bronchopulmonary dysplasia(BPD)in twin preterm infants with a gestational age of<34 weeks,and to provide a basis for early identification of BPD in twin preterm infants in clinical practice.Methods A retrospective analysis was performed for the twin preterm infants with a gestational age of<34 weeks who were admitted to 22 hospitals nationwide from January 2018 to December 2020.According to their conditions,they were divided into group A(both twins had BPD),group B(only one twin had BPD),and group C(neither twin had BPD).The risk factors for BPD in twin preterm infants were analyzed.Further analysis was conducted on group B to investigate the postnatal risk factors for BPD within twins.Results A total of 904 pairs of twins with a gestational age of<34 weeks were included in this study.The multivariate logistic regression analysis showed that compared with group C,birth weight discordance of>25%between the twins was an independent risk factor for BPD in one of the twins(OR=3.370,95%CI:1.500-7.568,P<0.05),and high gestational age at birth was a protective factor against BPD(P<0.05).The conditional logistic regression analysis of group B showed that small-for-gestational-age(SGA)birth was an independent risk factor for BPD in individual twins(OR=5.017,95%CI:1.040-24.190,P<0.05).Conclusions The development of BPD in twin preterm infants is associated with gestational age,birth weight discordance between the twins,and SGA birth.

Objective:To investigate the effect of feeder layer cells expressing interleukin(IL)-21 on the amplification of NK cells in vitro.Methods:The K562 cell line with IL-21 expression on its membrane was constructed by electroporation,and co-cultured with NK cells after inactivation.The proliferation of NK cells was observed.The killing function of the amplified NK cells in vitro was evaluated by the lactate dehydrogenase(LDH)and interferon-γ(IFN-y)release assay.A colorectal cancer xenograft model in NOD/SCID mice was established,and a blank control group,a NK cell group and an amplified NK cell group were set up to detect the tumor killing effect of amplified NK cells in vivo.Results:K562 cells expressing IL-21 on the membrane were successfully constructed by electroporation.After co-culturing with K562 cells expressing IL-21 on the membrane for 17 days,the NK cells increased to 700 times,which showed an enhanced amplification ability compared with control group(P＜0.001).In the tumor cell killing experiment in vitro,there was no significant difference in the killing activity on tumor cells between NK cells and amplified NK cells,and there was also no significant difference in mice in vivo.Conclusion:K562 cells expressing IL-21 on the membrane can significantly increase the amplification ability of NK cells in vitro,but do not affect the killing function of NK cells in vitro and in vivo.It can be used for the subsequent large-scale production of NK cells in vitro.

Aim To observe the behavioral effects of exogenous allopregnanolone(ALLO)and its inhibitor finasteride on the receptive period(R)and non-recep-tive period(NR)of PMDD liver-qi inversion model rats and the expression of GABAARα4,GABAARδ mR-NA and protein effects to explore its pathogenesis.Methods The PMDD liver-qi reverse syndrome rat model was prepared.The rats were divided into the normal group R and NR(control-R,control-NR),model group R and NR(Model-R,Model-NR),nor-mal group R+ALLO and NR+ALLO(Control+A-R,Control+A-NR),and model group R+ALLO and NR+ALLO(Model+A-R,Model+A-NR),model group R+finasteride and NR+finasteride(Model+F-R,Model+F-NR).The elevated cross labyrinth ex-periment and social interaction experiment were used to detect the behaviors of rats;fluorescence quantitative PCR and immunofluorescence were used to detect the expression of GABAARα4 and 8 mRNA and protein in rat amygdala and hippocampus.Results In the be-havioral evaluation,in the NR period,in the elevated cross maze test and in the social interaction test,the rats in the model group had anxiety behavior and de-creased social communication ability(P＜0.05),while the rats in the Model+A group could effectively relieve anxiety symptoms and improve their social com-munication ability(P＜0.05),and the rats in the Model+F group had increased anxiety behavior and social disorder(P＜0.05).In fluorescence quantita-tive PCR and immunofluorescence experiments,the ex-pression of GABAARα4 subunit in the model group was up-regulated in the hippocampus(P＜0.01),and the expression of δ subunit was down-regulated(P＜0.01);the expression of GABAARα4 subunit in the a-mygdala and hippocampus of the Model+A group de-creased(P＜0.01),and the expression of δ subunit increased in the hippocampus(P＜0.01).Conclu-sions The abnormal expression of GABAARα4 and 8 subunits mediated by ALLO improves the anxiety symptoms and social interaction ability of PMDD,which is the pathogenesis of PMDD liver-qi reverse syndrome,and provides basis and support for subse-quent exploration of the pathogenesis of PMDD liver-qi reverse syndrome.

Aim To explore the ameliorative effects of berberine(BBR)on diabetic nephropathy(DN)in mice and investigate its potential mechanisms through transcriptomic analysis.Methods 8-week-old db/db mice were randomly assigned into four groups:model group(DN group),BBR 50 mg·kg-1 group(BBR-L group),BBR 100 mg·kg-1 group(BBR-H group),and empagliflozin 10 mg·kg-1 group(EMPA group).Age-matched db/m mice were used as the control group(NC group),with eight mice in each group.Each group received intragastric administration once daily for eight weeks.After the treatment,serum,u-rine,and kidney samples were collected to evaluate re-nal function indicators and observe renal pathological changes.Differentially expressed genes(DEGs)in kidney tissue were identified through transcriptomic a-nalysis,followed by KEGG and GO enrichment analy-sis.Potential targets were further validated using mo-lecular docking,molecular dynamics simulations,West-ern blot,and immunohistochemistry.Results Both BBR and EMPA significantly reduced fasting blood glu-cose levels in DN mice,improved renal function,and alleviated renal injury and fibrosis.Compared to the NC group,855 DEGs were identified in the DN group,while 194 DEGs were identified in the BBR-H group compared to the DN group.KEGG enrichment analysis indicated that the mechanisms underlying BBR's effects on DN were primarily related to type 1 diabetes and bile secretion pathways.Molecular docking results demonstrated a strong binding affinity between BBR and FXR and a moderate binding affinity with SHP.Molecular dynamics simulations corroborated the doc-king results.FXR and SHP protein expression signifi-cantly decreased in the DN group compared to the NC group.At the same time,BBR treatment significantly increased the expression of these proteins compared to the DN group.Conclusion BBR may mitigate DN-in-duced renal injury by modulating bile acid and lipid homeostasis through the FXR-SHP pathway.