1.Huangqi Jianzhongtang Regulates Polarization of Macrophages M1/M2 and Improves Fat Consumption in Cancer Cachexia Mice
Zhiyan FANG ; Haiyan ZHU ; Wenying HUAI ; Cong HUANG ; Ruocong YANG ; Haiyan YU ; Tiane ZHANG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(2):61-69
ObjectiveTo investigate the effects of Huangqi Jianzhongtang (HQJZ) on macrophage polarization and fat consumption in cancer cachexia (CC) mice. MethodsUltra-performance liquid chromatography-quadrupole/electrostatic field Orbitrap high-resolution mass spectrometry (UPLC-Q-Orbitrap HRMS) was used to control the quality of HQJZ. (1) In vitro experiment: HQJZ-containing serum was prepared, and the optimal concentration was determined by cytotoxicity assay. Mouse monocyte-derived macrophages (RAW264.7) were cultured and randomly divided into six groups, including a blank group, a classically activated macrophages (M1) group, an alternatively activated macrophages (M2) group, a HQJZ + blank group, a HQJZ+M1 group, and a HQJZ + M2 group. The relative expression of macrophage marker genes CD86, inducible nitric oxide synthase (iNOS), CD206, and arginase-1 (Arg1) was detected by real-time quantitative polymerase chain reaction (Real-time PCR ). (2) In vivo experiment: Thirty-two BALB/c mice were randomly divided into a control group, a model group, a medroxyprogesterone acetate (MPA) group, and a HQJZ group. Except for the control group, the other mice were injected with CT-26 colon cancer cells to establish a CC model. Mice in the MPA and HQJZ groups were given MPA (0.13 g·kg-1·d-1) or HQJZ (13.13 g·kg-1·d-1) by gavage, respectively, while mice in the control and model groups were given an equal volume of saline by gavage, with interventions continued for 10 d. Real-time PCR was used to detect the expression of macrophage markers (iNOS, Arg1, CD86, CD206) and fat browning-related genes uncoupling protein 1 (UCP1) and peroxisome proliferator-activated receptor γ (PPARγ) in epididymal adipose tissue. Western blot (WB) was used to detect protein expression levels of UCP1 and PPARγ. Micro-computed tomography (micro-CT) was used to measure residual fat volume, and hematoxylin-eosin (HE) staining was used to assess fat browning and calculate pathological scores. ResultsIn vitro, the dominant effective concentration of HQJZ-containing serum was 12.5%. Real-time PCR results showed that, compared with the blank group, Arg1 expression decreased in the HQJZ+blank group (P<0.05), CD206 showed a downward trend without statistical significance, while iNOS and CD86 expression were significantly increased (P<0.05). Compared with the M1 group, Arg1 and CD206 expression decreased in the HQJZ+M1 group (P<0.05). Compared with the M2 group, CD206 expression decreased in the HQJZ+M2 group (P<0.05), CD86 expression increased significantly (P<0.01). In vivo, Real-time PCR results showed that, compared with the control group, CD86 and CD206 expression levels were significantly increased in the model group (P<0.01). Compared with the model group, CD206 expression in the MPA group was significantly decreased (P<0.01). In the HQJZ group, CD206 was significantly decreased (P<0.01). WB results showed that, compared with the model group, protein expression of UCP1 and PPARγ was significantly reduced in the HQJZ group (P<0.05, P<0.01). micro-CT results showed that the total white fat volume in the HQJZ group was greater than that in the model group (P<0.05). HE staining results showed that pathological scores in the HQJZ group were lower than those in the model group (P<0.05). ConclusionHQJZ may inhibit white adipose tissue browning by promoting macrophage M1 polarization and suppressing M2 polarization, thereby delaying fat consumption in CC mice.
2.Trend in disease burden of asthma attributable to tobacco in China from 1990 to 2021
MA Rongjiao ; HUANG Hanyan ; ZHU Manyu ; LIU Rui ; SHI Fang
Journal of Preventive Medicine 2026;38(1):89-92
Objective:
To investigate the trend in disease burden of asthma attributable to tobacco in China from 1990 to 2021, so as to provide the basis for improving intervention measures of asthma.
Methods:
Data on asthma-related mortality and disability-adjusted life years (DALY) attributable to tobacco among adults aged ≥30 years in China from 1990 to 2021 were collected from the Global Burden of Disease (GBD) 2021 database. Age-standardized mortality and age-standardized DALY rate were calculated using the GBD world standard population structure to analyze the tobacco-attributable asthma burden. The average annual percent change (AAPC) was employed to evaluate temporal trends in the age-standardized mortality and DALY rate from 1990 to 2021.
Results:
In China, the age-standardized mortality and age-standardized DALY rate of asthma attributable to tobacco decreased from 0.73/100 000 and 22.20/100 000 in 1990 to 0.17/100 000 and 6.64/100 000 in 2021, showing downward trends (AAPC=-4.603% and -3.888%, both P<0.05). Among males, the tobacco-attributable age-standardized mortality and age-standardized DALY rate declined from 1.44/100 000 and 41.05/100 000 in 1990 to 0.36/100 000 and 12.79/100 000 in 2021 (AAPC=-4.369% and -3.810%, both P<0.05). Among females, the corresponding rates decreased from 0.21/105 and 5.37/105 to 0.03/105 and 1.08/105 (AAPC=-6.074% and -5.074%, both P<0.05). In 2021, males had higher tobacco-attributable age-standardized mortality and age-standardized DALY rate for asthma than females. Both the mortality and DALY rate of asthma attributable to tobacco increased with age, peaking in the age group ≥80 years at 7.84/100 000 and 112.07/100 000, respectively.
Conclusion
From 1990 to 2021, the disease burden of asthma attributable to tobacco showed a declining trend in China, with males and elderly population aged ≥80 years bearing a relatively heavier disease burden.
3.Clinical effect of non-diffractive extended depth of focus IOL in patients with high myopia complicated with cataract
Yanhong JIA ; Xuemei LIANG ; Litao TAN ; Fang FU ; Yuanran PANG ; Kangming ZHU ; Li LI
International Eye Science 2026;26(4):700-705
AIM: To evaluate the postoperative clinical efficacy of non-diffractive extended depth of focus intraocular lens(EDOF IOL)in patients with highly myopic cataract(HMC).METHODS:A retrospective analysis was conducted on the clinical data of patients diagnosed with HMC at the hospital from January 2022 to December 2024. Patients were divided into an observation group [undergoing femtosecond laser-assisted cataract surgery(FLACS)combined with non-diffractive EDOF IOL implantation] and a control group(undergoing FLACS combined with aspheric monofocal IOL implantation)according to the type of implanted IOL. Postoperative visual acuity(LogMAR), visual quality, and patient satisfaction were compared between the two groups.RESULTS: A total of 33 patients(47 eyes)were finally included in this study, including 10 patients(17 eyes)in the observation group and 23 patients(30 eyes)in the control group. The observation group had a median age of 59.0(52.8, 63.8)y, with 8 males(13 eyes)and 2 females(4 eyes). The control group had a median age of 56.0(53.5, 60.0)y, with 13 males(17 eyes)and 10 females(13 eyes). At 3 mo postoperatively, the best-corrected distance visual acuity(BCDVA)was 0.10(0.08, 0.12)in the observation group and 0.20(0.10, 0.40)in the control group(P=0.586). However, the best-corrected intermediate visual acuity(BCIVA)[0.10(0.10, 0.10)vs 0.50(0.40, 0.90), P=0.032] and best-corrected near visual acuity(BCNVA)[0.20(0.18, 0.20)vs 0.60(0.45, 1.45), P=0.044] in the observation group were significantly better than those in the control group. The defocus curve showed that the uncorrected visual acuity(UCVA)in the observation group was relatively stable within the range of -2.00 to +1.00 D, which was superior to that in the control group. Postoperative questionnaires showed that the spectacle independence rate(76%)and overall satisfaction(88%)in the observation group were significantly higher than those in the control group(10% and 60%, respectively).CONCLUSION: Non-diffractive EDOF IOL significantly improves intermediate and near visual acuity, reduces spectacle dependence, and maintains distance visual acuity by extending the depth of focus, providing better postoperative visual quality and life satisfaction for HMC patients.
4.Mechanism of in Vitro and in vivo Models of Osteoporosis Regulation by Active Ingredients of Traditional Chinese Medicine: A Review
Ming YANG ; Jinji WANG ; Xuefeng ZHUANG ; Xiaolei FANG ; Zhijie ZHU ; Huiwei BAO ; Lijing LI
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(3):281-289
Osteoporosis is a common bone disease, whose incidence is still on the rise, posing great challenges to patients and society. This review mainly studies the pathogenesis of osteoporosis from the aspects of oxidative stress, inflammatory response, and glucolipotoxicity-induced injury and clarifies the efficacy and mechanism of some active ingredients of traditional Chinese medicine against osteoporosis through the integration of in vitro and in vivo experiments. The experimental results suggest that some active ingredients can improve bone resorption markers and maintain bone homeostasis by modulating inflammation, oxidative stress, etc. These active ingredients regulate osteoporosis through the receptor activator of nuclear transcription factor-κB (NF-κB) ligand (RANKL) pathway, osteoprotegerin (OPG) pathway, Wnt/β-catenin pathway, NF-κB pathway, mitogen-activated protein kinase (MAPK) pathway, adenosine monophosphate (AMP)-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway, and oxidative stress pathway. This review provides ideas for the progress of the prevention and treatment of osteoporosis with the active ingredients of traditional Chinese medicine, aiming to provide new potential lead compounds and reference for the development of innovative drugs and clinical therapy for the treatment of osteoporosis.
5.Prevalence and influencing factors of school bullying experienced by primary and middle school students
ZHU Yunjiao ; GU Fang ; MENG Jia ; LI Juanjuan ; SHEN Yu ; GAO Lei
Journal of Preventive Medicine 2025;37(1):1-6
Objective:
To investigate the situation and influencing factors of school bullying experienced by primary and middle school students, so as to provide the basis for formulating school bullying intervention measures and promoting students' physical and mental health development.
Methods:
All the counties (cities, districts) in Zhejiang Province were stratified to urban and suburban areas, primary, junior high and senior high school students were selected using a stratified cluster sampling method. Basic information, lifestyle and school bullying were collected through questionnaire surveys. Factors affecting school bullying experienced by primary and middle school students were analyzed using a multivariable logistic regression model.
Results:
Totally 137 846 valid questionnaires were recovered, with an effective recovery rate of 97.17%. There were 72 526 males (52.61%) and 65 320 females (47.39%). There were 47 561 primary school students (34.50%), 47 701 junior high school students (34.61%) and 42 584 senior high school students (30.89%). A total of 3 987 students suffered from school bullying, accounting for 2.89%. The proportions of being maliciously teased, being intentionally excluded from group activities/isolated, being teased about physical defects or appearance, being hit/kicked/pushed/shoved/locked in a room, being threatened, and being extorted for money were 2.04%, 1.18%, 1.11%, 0.86%, 0.84% and 0.83%, respectively. Multivariable logistic regression analysis showed that the students who were males (OR=1.122, 95%CI: 1.048-1.202), lived in suburban areas (OR=1.322, 95%CI: 1.233-1.418), lived in areas with medium (OR=1.086, 95%CI: 1.006-1.173) or underdeveloped (OR=1.298, 95%CI: 1.191-1.415) economic level, had higher academic levels (junior high school, OR=1.380, 95%CI: 1.270-1.499; senior high school, OR=1.210, 95%CI: 1.083-1.351), lived on campus (OR=1.489, 95%CI: 1.372-1.616), engaged in fights (OR=6.029, 95%CI: 5.585-6.509), attempted to smoke (OR=1.320, 95%CI: 1.128-1.545), drank (OR=1.735, 95%CI: 1.575-1.912), were scolded and beaten by parents (OR=1.972, 95%CI: 1.822-2.135) and were obese (OR=1.240, 95%CI: 1.132-1.360) were more likely to experience school bullying.
Conclusion
The harm of school bullying to the physical and mental health of primary and middle school students should be taken seriously, and active policy measures should be adopted to strengthen intervention.
6.Analgesic effect of acupuncture in a rat model of lumbar disc herniation
Fang ZHI ; Manhua ZHU ; Wei XIONG ; Xingzhen LIN
Chinese Journal of Tissue Engineering Research 2025;29(5):936-941
BACKGROUND:Acupuncture is an effective method for lumbar pain in lumbar disc herniation,but its mechanism has not yet been clarified.Factors related to the JAK2/STAT3 signaling pathway regulate the body's inflammatory response and are involved in the process of neuropathic pain. OBJECTIVE:To study the mechanism of acupuncture on lumbar disc herniation in a rat model based on the JAK2/STAT3 signaling pathway. METHODS:Forty Sprague-Dawley rats were randomly divided into four groups:sham operation group,model group,acupuncture group,and acupuncture+agonist group,with 10 rats in each group.Animal models of L5 lumbar disc herniation was constructed through autologous disc cell transplantation in the model group,acupuncture group,and acupuncture+agonist group.Rats in the acupuncture group and the acupuncture+agonist group received acupuncture treatment(Yanglingquan,Shenshu,Huantiao,and Dachangshu acupoints)at 3 days after modeling,and acupuncture treatment was given once a day,20 minutes each,for 15 consecutive days.Rats in the acupuncture+agonist group were injected intrathecally with coumermycin A1,a JAK2 agonist,into the L4/L5 intervertebral space,once a day,20 minutes each,prior to the acupuncture at 6,12,and 18 days after modeling.Paw withdrawal mechanical threshold was detected before and 3,6,9,12,15,and 18 days after modeling.At 18 days after modeling,serum inflammatory factor levels were detected,hematoxylin-eosin staining was performed to observe the morphology of L5-L6 tissues,RT-PCR was performed to detect the expression of JAK2 and STAT3 mRNAs in L5-L6 tissues,and western blot was performed to detect the expression of JAK2,p-JAK2 and p-STAT3 proteins in L5-L6 tissues. RESULTS AND CONCLUSION:The paw withdrawal mechanical thresholds of rats in the model group at different time points after modeling were lower than those in the sham operation group(P<0.05),the paw withdrawal mechanical thresholds of rats in the acupuncture group were higher than those in the model group at 9,12,15,and 18 days after modeling(P<0.05),and the paw withdrawal mechanical thresholds of rats in the acupuncture+agonist group were lower than those in the acupuncture group at 9,12,15,and 18 days after modeling(P<0.05).The levels of interleukin 6,tumor necrosis factor α,neurotransmitter substance P,and brain neuropeptide Y were elevated in the model group compared with the sham operation group(P<0.05);the levels of all four inflammatory factors were reduced in the acupuncture group compared with the model group(P<0.05);and the levels of all four inflammatory factors were elevated in the acupuncture+agonist group compared with the acupuncture group(P<0.05).Hematoxylin-eosin staining showed that lumbar degeneration was obvious in the model group but reduced in the acupuncture group and the acupuncture+agonist group.Moreover,the reduction was more obvious in the acupuncture group compared with the acupuncture+agonist group.The JAK2 and STAT3 mRNA expression as well as the p-JAK2 and p-STAT3 protein expression were elevated in the model group compared with the sham operation group(P<0.05),were decreased in the acupuncture group compared with the model group(P<0.05),and were increased in the acupuncture+agonist group compared with the acupuncture group(P<0.05).To conclude,acupuncture can alleviate inflammation to exert analgesic effects in the rat model of lumbar disc herniation,and its mechanism of action may be related to the inhibition of the JAK2/STAT3 signaling pathway.
7.Adult stem cells from different germ layers applied in peripheral nerve injury repair
Jiachen ZHENG ; Entong YANG ; Yizhou ZHU ; Fang LIU
Chinese Journal of Tissue Engineering Research 2025;29(19):4102-4110
BACKGROUND:Adult stem cell therapy is one of the research hotspots in the field of peripheral nerve injury repair and regeneration.With excellent properties of mesenchymal stem cells such as high acquisition rate,wide source,and rapid proliferation,mesoderm have been regarded as the ideal source of adult stem cells,while ectoderm-derived adult stem cells,especially neural crest stem cells,have certain neurogenic properties and attract more and more attention from researchers. OBJECTIVE:To mainly review the role and mechanism of multifunctional adult stem cells from ectoderm and mesoderm in peripheral nerve injury repair and regeneration,so as to explore the research progress and application prospect of adult stem cells from different sources and discuss the potential application value of adult stem cell therapy and the problems to be solved in connection with clinical studies. METHODS:The first author searched the relevant articles published from December 2001 to February 2024 in PubMed and SinoMed by computer in February 2024.The Chinese and English search terms were"ectodermal stem cells,mesenchymal stem cells,peripheral nerve injury,repair,regeneration."Finally,69 articles were included and analyzed. RESULTS AND CONCLUSION:(1)Ectodermal adult stem cells have excellent differentiation and regeneration potential,especially epidermal neural crest stems cells,olfactory stem cells,and dental ectomesenchymal stem cells,which have certain neurogenic properties and can express neural specific markers in vitro.However,relevant clinical research needs to be accumulated.(2)There are many types of adult stem cells derived from mesoderm,which are easy to obtain and purify.Among them,the efficacy and safety of bone marrow mesenchymal stem cells and umbilical cord mesenchymal stem cells in the repair of peripheral nerve injury are supported by clinical trials;that is,they can improve sensory and motor nerve conduction and there are no complications and obvious adverse reactions in follow-up.The acquisition of bone marrow mesenchymal stem cells needs invasive surgery and requires the patient to match the donor bone marrow type,which limit the application to some extent.Although umbilical cord mesenchymal stem cells do not require invasive harvesting,their isolation is difficult and phenotypically unstable.(3)Adult stem cells derived from endoderm often fail to grow in vitro,so the possibility of clinical application is low.(4)In conclusion,bone marrow mesenchymal stem cells are still the first choice for adult stem cell therapy in the treatment of peripheral nerve injury,which is suitable for cases without surgical contraindications and meeting the matching requirements,followed by umbilical cord mesenchymal stem cells supplemented by improved isolation methods and advanced phenotypic stability strategies.(5)Dental ectomesenchymal stem cells and adipose-derived mesenchymal stem cells have high application potential and need to be further tested in clinical trials.Other adult stem cells derived from ectodermal and mesodermal layers have significant advantages in animal and cell experimental studies due to their excellent properties.
8.USP29 alleviates the progression of MASLD by stabilizing ACSL5 through K48 deubiquitination
Sha HU ; Zhouxiang WANG ; Kun ZHU ; Hongjie SHI ; Fang QIN ; Tuo ZHANG ; Song TIAN ; Yanxiao JI ; Jianqing ZHANG ; Juanjuan QIN ; Zhigang SHE ; Xiaojing ZHANG ; Peng ZHANG ; Hongliang LI
Clinical and Molecular Hepatology 2025;31(1):147-165
Background/Aims:
Metabolic dysfunction–associated steatotic liver disease (MASLD) is a chronic liver disease characterized by hepatic steatosis. Ubiquitin-specific protease 29 (USP29) plays pivotal roles in hepatic ischemiareperfusion injury and hepatocellular carcinoma, but its role in MASLD remains unexplored. Therefore, the aim of this study was to reveal the effects and underlying mechanisms of USP29 in MASLD progression.
Methods:
USP29 expression was assessed in liver samples from MASLD patients and mice. The role and molecular mechanism of USP29 in MASLD were assessed in high-fat diet-fed and high-fat/high-cholesterol diet-fed mice and palmitic acid and oleic acid treated hepatocytes.
Results:
USP29 protein levels were significantly reduced in mice and humans with MASLD. Hepatic steatosis, inflammation and fibrosis were significantly exacerbated by USP29 deletion and relieved by USP29 overexpression. Mechanistically, USP29 significantly activated the expression of genes related to fatty acid β-oxidation (FAO) under metabolic stimulation, directly interacted with long-chain acyl-CoA synthase 5 (ACSL5) and repressed ACSL5 degradation by increasing ACSL5 K48-linked deubiquitination. Moreover, the effect of USP29 on hepatocyte lipid accumulation and MASLD was dependent on ACSL5.
Conclusions
USP29 functions as a novel negative regulator of MASLD by stabilizing ACSL5 to promote FAO. The activation of the USP29-ACSL5 axis may represent a potential therapeutic strategy for MASLD.
9.Treatment of Sepsis-induced Inflammatory Responses with Xijiao Dihuangtang by Modulation of PKM2-mediated One-carbon Metabolism Pathway
Qixiang YAN ; Yeyan ZHU ; Fan GE ; Qimeng SUN ; Leyao YE ; Fang TIAN ; Jun LU
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(10):18-26
ObjectiveTo investigate the effects of Xijiao Dihuangtang (XJDHT) on mice with sepsis and cellular models of sepsis and explore its molecular mechanism in alleviating sepsis-induced inflammatory responses via regulating pyruvate kinase M2 (PKM2)-mediated one-carbon metabolism pathway. MethodsForty C57BL/6N mice were randomly divided into four groups: normal group, model group, low-dose XJDHT group (7.7 g·kg-1), and high-dose XJDHT group (15.4 g·kg-1). After one week of continuous gavage, sepsis was induced using cecal ligation and puncture (CLP) in groups except the normal group. 24 h after the surgery, mortality rates in all groups were recorded, and serum cytokines were measured by enzyme linked immunosorbent assay (ELISA). Lung histopathology was examined by hematoxylin-eosin (HE) staining. During the in vitro experiment, the human monocytic leukemia cell line (THP-1) was exposed to various concentrations of XJDHT and treated with lipopolysaccharide (LPS) at a final concentration of 2 mg·L-1 for 24 h. Cell apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Protein levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), B-cell lymphoma 2 (Bcl-2), and Bcl-2-associated X protein (Bax) were measured by Western blot. Transcriptome sequencing was performed to analyze differentially expressed genes in all groups and conduct gene ontology (GO) enrichment. Key genes in the one-carbon metabolism pathway, including pyruvate kinase M2 (PKM2), 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), and phosphoglycerate dehydrogenase (PHGDH), were verified by Western blot. A PKM2 inhibition model was established using shikonin for further protein expression analysis. ResultsAnimal experiments showed that compared with the normal group, the model group exhibited significantly elevated body temperature and lung pathology (P<0.01) and increased serum TNF-α and IL-1β levels (P<0.01). High-dose XJDHT reduced body temperature and lung tissue damage (P<0.01) and significantly decreased serum TNF-α and IL-1β levels (P<0.01). Low-dose XJDHT treatment showed no significant temperature change (P<0.01) but reduced serum TNF-α and IL-1β levels (P<0.01). Transcriptome sequencing and Western blot revealed significant differences in the expression of TNF-α, IL-1β, and one-carbon metabolism genes (PKM2, MTR, and PHGDH) (P<0.01). Cell experiments demonstrated that compared to the normal group, the model group showed elevated protein expressions of TNF-α and IL-1β in THP-1 cells (P<0.01), decreased Bcl-2/Bax ratio, and increased apoptosis (P<0.01). Transcriptome sequencing and Western blot revealed significant differences in the expression of TNF-α, IL-1β, and one-carbon metabolism genes (PKM2, MTR, and PHGDH) (P<0.01). Compared to the model group, high-dose XJDHT significantly increased Bax/Bcl-2 ratio and PHGDH protein expression (P<0.01) and effectively reduced cell apoptosis (P<0.01) while down-regulating protein expressions of TNF-α, IL-1β, PKM2, and MTR (P<0.01). Low-dose XJDHT moderately increased Bax/Bcl-2 ratio and PHGDH protein expression (P<0.05), reduced apoptosis (P<0.05), and decreased IL-1β and MTR protein levels (P<0.05, P<0.01), but there were no significant changes in TNF-α and PKM2 expression. After PKM2 inhibition by shikonin in THP-1 cells, the expression of protein related to one-carbon metabolism was detected. Compared with the blank group, the LPS-induced model group showed significantly upregulated PKM2 and MTR protein expression (P<0.01) and downregulated PHGDH expression (P<0.01). Compared with the model group, shikonin treatment significantly reduced PKM2 expression (P<0.05), increased PHGDH expression (P<0.01), and decreased MTR expression (P<0.05). ConclusionXJDHT can inhibit the release of inflammatory factors in sepsis, and its mechanism is related to the intervention of the PKM2-regulated one-carbon metabolism pathway in macrophages.
10.Structural and Spatial Analysis of The Recognition Relationship Between Influenza A Virus Neuraminidase Antigenic Epitopes and Antibodies
Zheng ZHU ; Zheng-Shan CHEN ; Guan-Ying ZHANG ; Ting FANG ; Pu FAN ; Lei BI ; Yue CUI ; Ze-Ya LI ; Chun-Yi SU ; Xiang-Yang CHI ; Chang-Ming YU
Progress in Biochemistry and Biophysics 2025;52(4):957-969
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.


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