1.Species of sandflies and prevalence of Leishmania infections in sandflies in selected areas of northern and northwestern China
Yaqi HE ; Lei CUI ; Yi ZHANG ; Yuanyuan LI ; Limin YANG ; Yuan FANG ; Zhongqiu LI ; Zhengbin ZHOU
Chinese Journal of Schistosomiasis Control 2026;38(1):20-28
Objective To investigate the species of sandflies and the prevalence of Leishmania infections in sandflies from selected areas of northern and northwestern China, so as to provide insights into identification of leishmaniasis vectors and assessment of epidemiological trends of leishmaniasis in China. Methods Sandfly samples were collected from Mentougou District of Beijing Municipality, Xiangning County in Linfen City of Shanxi Province, Ejin Banner in Alxa League of Inner Mongolia Autonomous Region, and Payzawat County of Karamay District of Karamay City, Gaochang District of Turpan City in Xinjiang Uygur Autonomous Region from July 2023 to July 2024. Approximately 100 intact female sandfly samples were randomly selected from each site and the species of sandflies was identified according to morphological characteristics and molecular assays. Female sandflies originating from the same habitat were grouped into pools of 10 individuals. Leishmania infection was detected using polymerase chain reaction (PCR) assay targeting the internal transcribed spacer 1 (ITS-1) gene, and the prevalence of Leishmania infection was calculated in sandflies from different sampling sites using the minimum infection rate (MIR) method. In addition, positive amplicons were sequenced and subjected to phylogenetic analysis. Results A total of 6 155 sandflies were collected from different environments at sampling sites across the six aforementioned regions from July 2023 to July 2024. Phlebotomus chinensis (96.00%) was the dominant sandfly species in Mentougou District, Beijing Municipality, with a small proportion of Ph. sergenti (4.00%), and only Ph. chinensis was found in Xiangning County, Linfen City, Shanxi Province. Ph. wui was the only sandfly species detected in Ejin Banner, Alxa League, Inner Mongolia Autonomous Region, and Payzawat County, Kashgar City, Xinjiang Uygur Autonomous Region, and Ph. caucasicus (97.70%) was the dominant sandfly species in Karamay District, Karamay City, Xinjiang Uygur Autonomous Region, with a small proportion of Ph. wui (2.30%), while Ph. alexandri was the only species in Gaochang District, Turpan City, Xinjiang Uygur Autonomous Region. A total of 40, 60, 34, 18, 18, and 22 pools of sandfly samples were tested from Mentougou District in Beijing Municipality, Xiangning County in Linfen City of Shanxi Province, Ejin Banner in Alxa League of Inner Mongolia Autonomous Region, Payzawat County in Kashgar City, Karamay District in Karamay City, and Gaochang District in Turpan City of Xinjiang Uygur Autonomous Region, respectively. L. infantum was detected in Ph. chinensis samples from Mentougou District in Beijing Municipality, and Xiangning County of Linfen City in Shanxi Province, with MIR of 0.25% to 1.00%, and L. donovani was detected in Ph. wui from Ejin Banner in Alxa League of Inner Mongolia Autonomous Region, and Payzawat County in Kashgar City of Xinjiang Uygur Autonomous Region, with MIR of 0.56% to 0.88%; however, no Leishmania infection was detected in Ph. caucasicus from Karamay District in Karamay City or Ph. alexandri from Gaochang District in Turpan City of Xinjiang Uygur Autonomous Region. Phylogenetic analysis showed that the Leishmania ITS-1 gene sequences obtained from Mentougou District in Beijing Municipality and Xiangning County in Linfen City of Shanxi Province were clustered into the same clade with the reference sequences of L. infantum ITS-1 gene, while the Leishmania ITS-1 gene sequences obtained from Ejin Banner in Alxa League of Inner Mongolia Autonomous Region and Payzawat County in Kashgar City of Xinjiang Uygur Autonomous Region were clustered into the same clade with the reference sequences of L. donovani ITS-1 gene. Conclusions There are variations in sandfly species in selected areas of northern and northwestern China, and variations in the species of Leishmania infecting sandflies. Improved surveillance of sandfly vectors and targeted control strategies with adaptations to geographical features and leishmaniasis vectors are recommended.
2.The Role and Regulatory Mechanisms of FOXO1 in Hepatic Lipid Deposition
Meng JIA ; Fang-Hui LI ; Shi-Zhan YAN ; Ai-Ju LI ; Yi-Le WANG ; Pin-Shi NI ; Jia-Han HE ; Yin-Lu LI
Progress in Biochemistry and Biophysics 2026;53(4):905-919
Metabolic associated fatty liver disease (MAFLD) is fundamentally driven by an imbalance in hepatic fatty-acid flux: the influx of fatty acids exceeds the liver’s capacity for disposal, resulting in excessive hepatic lipid accumulation, predominantly in the form of triglycerides (TGs). The occurrence and progression of MAFLD depend on disordered regulation across multiple metabolic steps, including fatty-acid uptake, de novo lipogenesis (DNL), fatty-acid oxidation (FAO), and very low-density lipoprotein (VLDL) export. Forkhead box protein O1 (FOXO1) is a key transcriptional regulator within the hepatic network coordinating glucose and lipid metabolism. Under metabolic stress and insulin resistance (IR), FOXO1 expression is frequently increased, whereas its inhibitory phosphorylation is reduced. These changes enhance FOXO1 nuclear localization and transcriptional activity, thereby reprogramming the expression of genes related to metabolism in the liver. Because hepatic lipid deposition is the central pathological feature of MAFLD, the functional status of FOXO1 directly influences hepatic lipid homeostasis. Growing evidence suggests that FOXO1 can exert bidirectional, environment-dependent effects on hepatic lipid accumulation; however, the molecular basis for this functional switch remains incompletely understood. This review systematically summarizes the biological functions and regulatory mechanisms of FOXO1 and its roles in hepatic lipid metabolism, with a particular focus on its crosstalk with insulin signaling. FOXO1 expression is shaped by RNA modifications and epigenetic regulation mediated by non-coding RNAs. Its transcriptional output is precisely governed by post-translational modifications—such as phosphorylation and acetylation—as well as by coordinated nucleocytoplasmic shuttling. Notably, these regulatory patterns vary markedly across nutritional states, degrees of insulin resistance, and stages of disease. In the fed state, insulin/IGF-1 signaling activates the PI3K-AKT pathway, promoting the inhibitory phosphorylation of FOXO1 and facilitating additional modifications, including acetylation, methylation, and ubiquitination. Together, these events drive FOXO1 export from the nucleus and dampen its transcriptional activity, suppressing gluconeogenesis and constraining lipogenic programs. Conversely, during fasting or when insulin signaling is weakened, FOXO1 inhibition is relieved. FOXO1 accumulates in the nucleus, binds to DNA, and regulates the transcription of downstream target genes. Mechanistically, FOXO1 can aggravate hepatic lipid accumulation by activating genes involved in TG synthesis while repressing FAO-related pathways, thereby favoring storage over oxidation. However, under specific conditions, FOXO1 may also alleviate the hepatic lipid burden by promoting TG hydrolysis and enhancing VLDL secretion, thereby reducing the net hepatic lipid load. In addition, lipotoxic signals mediated by ceramides and diacylglycerols (Cer/DAG) activate atypical protein kinase C (aPKC), further exacerbating the disruption of the AKT-FOXO1 axis. This vicious cycle ultimately produces a metabolic paradox in which increased hepatic glucose output coexists with persistent, insulin-independent lipogenesis, accelerating MAFLD progression. Importantly, FOXO1 regulation is not uniform: during early metabolic overload, insulin-mediated suppression may remain effective, whereas in advanced insulin resistance, the loss of AKT control permits sustained FOXO1 activity. Such stage-dependent dynamics may help explain why FOXO1 can either promote steatosis or, in certain contexts, support programs that facilitate lipid turnover. Accordingly, interventions should be liver-specific and tuned to the disease stage, aiming to curb maladaptive FOXO1 signaling while preserving its capacity to promote triglyceride hydrolysis and VLDL secretion when advantageous. Overall, this review offers an important perspective on MAFLD pathogenesis, emphasizing FOXO1 as a potential therapeutic target and providing a theoretical basis for developing liver-specific, disease-course-dependent precision interventions.
3.Mechanism of Electroacupuncture Alleviating Inflammatory Pain in Rats by Regulating ErbB Subtypes in the Spinal Dorsal Horn
Yuxin WU ; Shuxin TIAN ; Zhengyi LYU ; Dingru JI ; Xingzhen LI ; Yue DONG ; Binyu ZHAO ; Yi LIANG ; Jianqiao FANG
Journal of Traditional Chinese Medicine 2026;67(1):69-78
ObjectiveTo observe the changes in the levels of different subtypes of epidermal growth factor receptor (ErbB), namely ErbB1, ErbB2, ErbB3, and ErbB4, in the spinal dorsal horn of inflammatory pain model rats, and to explore their mechanism of mediating hyperalgesia as well as the intervention mechanism of electroacupuncture at "Zusanli (ST 36)" and "Kunlun (BL 60)". MethodsThe study was divided into five parts. In experiment 1, 14 Sprague Dawley (SD) rats were randomly divided into control and inflammatory pain group (7 rats each group) to observe the pain behavior and the protein expression of different ErbB receptor subtypes in the spinal dorsal horn. In experiment 2, 30 rats were randomly divided into control group 1, inflammatory pain group 1, and low-, medium-, and high-concentration TX1-85-1 groups, with 6 rats in each group, to observe the effect of inhibiting spinal ErbB3 on inflammatory pain. In experiment 3, 12 rats were randomly divided into control virus group and ErbB3 knockdown virus group, with 6 rats in each group, to observe the effect of knocking down ErbB3 in the spinal dorsal horn on inflammatory pain. In experiment 4, 44 rats were randomly divided into control group 2, inflammatory pain group 2, electroacupuncture group, and sham electroacupuncture group, with 11 rats in each group, to observe the effect of electroacupuncture. In experiment 5, 40 rats were randomly divided into control group 3, inflammatory pain group 3, electroacupuncture group 1, and electroacupuncture + NRG1 group, with 10 rats in each group, to observe the effect of activating ErbB3 on electroacupuncture. A rat model of inflammatory pain was established by subcutaneous injection of 100 μl of complete Freund's adjuvant into the sole of the unilateral hind foot of SD rats. Rats in the low-, medium-, and high-concentration TX1-85-1 groups were intrathecally injected with ErbB3 inhibitor TX1-85-1 on day 5 to day 7 after modeling. Rats in the ErbB3 knockdown virus group were injected with ErbB3 knockdown virus packaged with adenovirus vector-based short hairpin RNA (shRNA) into the spinal dorsal horn in situ 3 weeks before modeling. Rats in each electroacupuncture group received electroacupuncture at bilateral "Zusanli (ST 36)" and "Kunlun (BL 60)" from day 1 to day 7 after modeling, with dense-sparse waves at a frequency of 2 Hz/100 Hz and a current of 0.5-1.5 mA for 30 minutes once a day. Rats in the electroacupuncture + NRG1 group were intrathecally injected with ErbB3 ligand recombinant human neuregulin-1 (NRG1) after electroacupuncture intervention from day 5 to day 7 after modeling. The mechanical withdrawal threshold and thermal withdrawal latency of rats were measured on day 1, 3, 5, and 7 after modeling to evaluate behavior, and Western Blot was used to detect the protein and phosphorylation levels of each ErbB subtype in the spinal dorsal horn. ResultsCompared with the control group, rats in the inflammatory pain group showed decreased mechanical withdrawal threshold and thermal withdrawal latency of rats, and increased expression of phosphorylated ErbB3 (p-ErbB3) protein in the spinal dorsal horn on days 1, 3, 5, and 7 after modeling (P<0.01). On day 5 and day 7 after modeling, compared with the inflammatory pain group 1, the mecha-nical withdrawal threshold and thermal withdrawal latency of rats in the medium- and high-concentration TX1-85-1 groups increased, and the expression of p-ErbB3 protein decreased (P<0.05). On day 1, 3, 5, and 7 after modeling, compared with the control virus group, the mechanical withdrawal threshold and thermal withdrawal latency of rats in the ErbB3 knockdown virus group increased (P<0.05). On day 5 and day 7 after modeling, compared with the inflammatory pain group 2 and the sham electroacupuncture group, the mechanical withdrawal threshold and thermal withdrawal latency of rats in the electroacupuncture group increased, and the expression of p-ErbB3 protein decreased (P<0.05). On day 5 and day 7 after modeling, compared with the electroacupuncture + NRG1 group, the mechanical withdrawal threshold and thermal withdrawal latency of rats in the electroacupuncture group 1 increased (P<0.05). ConclusionThe p-ErbB3 in the spinal dorsal horn involved in hyperalgesia in rats with inflammatory pain, and electroacupuncture at "Zusanli (ST 36)" and "Kunlun (BL 60)" can alleviate inflammatory pain by inhibiting the expression of p-ErbB3 protein in the spinal dorsal horn of rats.
4.Changes of lymphocyte subsets in peripheral blood and immunological pathogenesis of Graves disease
Tieqiang LIU ; Shan HUANG ; Li LIAO ; Xinyang LI ; Peng SUN ; Yi WANG ; Yijian ZHANG ; Bingxia LI ; Xuemin WEI ; Yufang LI ; Shixin SUN ; Yanli NI ; Yi FANG ; Bin ZHANG
Chinese Journal of Laboratory Medicine 2025;48(11):1439-1445
Objective:To retrospectively analyze the changes in the proportion of refined lymphocyte subsets in peripheral blood of patients with Graves disease (GD), and their correlation with the clinical characteristics and efficacy of GD, and to explore the immunological pathogenesis of Graves disease for seeking new therapeutic targets.Methods:A total of 97 newly diagnosed GD patients (GD group), 27 patients after treatment (treatment group), and 31 healthy individuals (control group) who visited the Fifth Medical Center of the PLA General Hospital from 2018 to 2021 were included in this study. The data of refined lymphocyte subsets, thyroid function, blood routine and clinical treatment of the three groups were compared and analyzed. The t-test and rank sum test were used to compare the proportions of lymphocyte subsets among different groups, and Pearson correlation analysis was used to analyze the correlation between the proportions of lymphocyte subsets and thyroid function indicators.Results:The proportion of B cells in GD group was higher than that in the control group [16.2%(11.8%, 21.8%) vs 10.2%(8.1%,13.6%)], while the proportion of natural killer (NK) cells was lower [9.4%(4.9%, 13.6%) vs 14.6%(12.1%,18.8%)], and the differences were statistically significant ( P<0.05). Abnormal T cell differentiation: the proportions of functional cells, including activated T cells, memory T cells, clustering antigen(CD)4+memory T cells, Th1 cells, and Tc1 cells, were lower than that in the control group [3.2%(2.1%, 5.7%) vs 5.8%(3.0%, 9.3%), P<0.05; 36.7% (29.9%, 48.1%) vs 48.0%(39.2%,57.7%), P<0.05; 23.1%(17.4%, 30.1%) vs 28.9%(23.3%,34.6%), P<0.05; 16.4% (11.8%, 23.6%) vs 24.3%(16.9%,28.5%), P<0.05; 28.5% (14.7%, 39.2%) vs 46.3%(21.6%,69.2%), P<0.05]. The proportion of activated T cells in the treatment group was higher than that in the GD group [6.5% (4.6%, 13.6%) vs 3.2% (2.1%, 5.7%), P<0.05]. The total triiodothyronine results showed positive correlations with B cells ( r=0.356, P<0.01) and negative correlations with NK cells ( r=?0.416, P<0.01), while the total thyroxine values showed negative correlations with NK cells and activated T cells ( r=?0.318,?0.335; P<0.01). Thyroid stimulating hormone and CD8+initial T cells were positively correlated ( r=0.382, P<0.01). The proportion of B cells, cytotoxic T cells and suppressor T cells in CD8+cells of patients with complications [such as Graves orbitopathy (GO), thyroid toxic cardiomyopathy, etc.] was significantly different from that of the simple GD patients [18.3% (14.1%, 27.1%) vs 14.6% (10.8%, 21.4%), Z=2.54, P<0.05; 73.4%(65.6%,83.6%)vs 65.0%(50.3%,79.3%), Z=2.93, P<0.05; 26.6%(16.4%, 37.5%)vs 35.0%(20.7%,49.7%), Z=?2.74, P<0.05]. The proportion of suppressor T cells in GO patients was lower than that in non-GO patients [6.1% (3.4%, 8.1%) vs 8.5% (4.9%, 13.6%), Z=?3.20 P<0.05]. Conclusion:There are significant alterations in the circulating immune cells of GD patients, suggesting that immunological abnormalities play a crucial role in the onset and progression of the disease.
5.Analysis of the financial status of urban public hospitals in China based on DuPont analysis system
Yi ZHOU ; Zixuan WANG ; Siping DONG ; Fang LIU ; Xiqin LI
Chinese Journal of Hospital Administration 2025;41(2):90-95
Objective:To analyze the financial status of urban public hospitals in China and provide references for promoting the integration of business and finance as well as refined management in urban public hospitals.Methods:Based on the financial data of urban public hospitals in 31 provinces, autonomous regions, municipalities directly under the central government, and the Xinjiang Production and Construction Corps (excluding Hong Kong, Macao, and Taiwan) from the annual financial reports of public hospitals issued by the Department of Finance of the National Health Commission during 2019—2021, the DuPont analysis system was employed to dissect the financial status of urban public hospitals in China, with return on net assets as the core indicator. The profitability was measured by return on net assets, the operational capability was measured by the total asset turnover rate, and the debt-paying ability was measured by the short-term debt-paying ability indicator, current ratio, and the long-term debt-paying ability indicator, debt-to-asset ratio.Results:From 2019 to 2021, the number of urban public hospitals in China were 2 752, 2 797, and 2 815, respectively. The return on net assets was 8.83%, 9.29%, and 7.65%, respectively, with the changes mainly influenced by medical revevene surplus rate. The total asset turnover rate was 81.92%, 68.36%, and 73.54%, respectively, with the changes mainly affected by total assets and medical income. The current ratios were 1.23, 1.20, and 1.16, respectively, while the debt-to-asset ratios were 44.88%, 44.47%, and 43.86%, respectively, which remained at a relatively high level. The proportion of non-current assets was 53.50%, 55.26%, and 56.88%, respectively.Conclusions:From 2019 to 2021, the profitability and operational efficiency of urban public hospitals in China both declined, showing a current operational status of high asset intensity and high debt. It is recommended that national administrative departments increase financial input and optimize asset allocation. Urban public hospitals should enhance comprehensive budget management and improve the refinement level of operational management to achieve efficient and sustainable development.
6.Establishment of quantitative models for effective components in Yishen Xiezhuo Mixture
Zi-fang FENG ; Min-min HU ; Xiao-wei CHEN ; Wen-ming ZHANG ; Li-hong GU ; Ping QIN ; Yi PENG ; Zhen-hua BIAN ; Qing-you YANG ; Tu-lin LU
Chinese Traditional Patent Medicine 2025;47(10):3177-3184
AIM To establish the quantitative models for gallic acid,mononucleoside,loganin,resveratrol,and rhein in Yishen Xiezhuo Mixture.METHODS HPLC was adopted in the content determination of various effective components,after which the near-infrared spectroscopy(NIRS)data were collected in 128 batches of samples and pretreatment was conducted,competitive adaptive reweighting sampling(CARS)algorithm was used for screening wavelength,partial least square method(PLS)regression analysis was performed.RESULTS There were no significant differences between the predicted values obtained by PLS models and measured values obtained by HPLC for various effective components(P>0.05).CONCLUSION The quantitative models established by NIRS combined with chemometrics display good predictive performance,which can be used for the rapid determination of effective components in Yishen Xiezhuo Mixture,and provide a reference for the rapid monitoring of other traditional Chinese medicine preparations in production processes.
7.Ameliorative effects of Compound Fufangteng Mixture on cyclophosphamide-induced immunosuppression in mice
Li-na LIU ; Yu-fang SHEN ; Qin-qin WANG ; Lin-yu XIAO ; Jing-yu LIU ; Jun-ni MO ; Ren-yi-kun YUAN ; Hong-wei GAO ; Jian XIAO
Chinese Traditional Patent Medicine 2025;47(10):3249-3256
AIM To investigate the ameliorative effects of Compound Fufangteng Mixture(CFM)on cyclophosphamide(CTX)-induced immunosuppression in mice.METHODS Forty-eight male C57BL/6J mice were randomly divided into the blank control group,the model group,the levamisole hydrochloride group(40 mg/kg)and the low-dose,medium-dose and high-dose CFM groups(3.75,7.5,10 g/kg),with 8 mice in each group,and given respective intervention orally once daily for 14 days.On the 5th to 7th day of administration,with the blank control group given normal saline intraperitoneally,the other groups underwent intraperitoneal CTX injections(80 mg/kg).24 hours after the last administration,organ indices of thymus and spleen were calculated;splenic histopathological alterations were assessed by HE staining;serum levels of IL-2,IL-6 and IgG were quantified using ELISA;splenic CD4+,CD8+T lymphocytes,alongside CD86+and CD206+macrophages populations were analyzed by flow cytometry;and splenic expression of CD4,CD8 and F4/80 was evaluated by immunohistochemical staining.RESULTS In CTX-treated mice,CFM administration mitigated body weight loss;enhanced thymus weight and thymic index;ameliorated splenic immune cell populations,elevated serum levels of cytokines IL-2,IL-6 and IgG in serum;and upregulated splenic levels of CD45+CD3+T lymphocytes and F4/80+CD11b+macrophages,alongside increasing the expression of CD4,CD8 and F4/80 surface markers.CONCLUSION CFM alleviates CTX-induced immunosuppression state in mice by modulating immune cells,restoring immune function and enhancing anti-inflammatory and tissue repair capabilities.
8.Exosomal circRNAs:Deciphering the novel drug resistance roles in cancer therapy
Xi LI ; Hanzhe LIU ; Peiyu XING ; Tian LI ; Yi FANG ; Shuang CHEN ; Siyuan DONG
Journal of Pharmaceutical Analysis 2025;15(2):342-358
Exosomal circular RNA(circRNAs)are pivotal in cancer biology,and tumor pathophysiology.These stable,non-coding RNAs encapsulated in exosomes participated in cancer progression,tumor growth,metas-tasis,drug sensitivity and the tumor microenvironment(TME).Their presence in bodily fluids positions them as potential non-invasive biomarkers,revealing the molecular dynamics of cancers.Research in exosomal circRNAs is reshaping our understanding of neoplastic intercellular communication.Exploiting the natural properties of exosomes for targeted drug delivery and disrupting circRNA-mediated pro-tumorigenic signaling can develop new treatment modalities.Therefore,ongoing exploration of exoso-mal circRNAs in cancer research is poised to revolutionize clinical management of cancer.This emerging field offers hope for significant breakthroughs in cancer care.This review underscores the critical role of exosomal circRNAs in cancer biology and drug resistance,highlighting their potential as non-invasive biomarkers and therapeutic targets that could transform the clinical management of cancer.
9.Consensus on the use of DSA-guided intrathecal drug delivery system combined with Zi Wu Liu Zhu Acupoint Therapy for cancer pain management
Yi LU ; Cunzhi LIU ; Wujun GENG ; Xiaozhen ZHENG ; Jingdun XIE ; Guangfang ZHANG ; Chao LIU ; Yun LI ; Yan QU ; Lei CHEN ; Xizhao HUANG ; Hang TIAN ; Yuhui LI ; Hongxin LI ; Heying ZHONG ; Ronggui TAO ; Jie ZHONG ; Yue ZHUANG ; Junyang MA ; Yan HU ; Jian FANG ; Gaofeng ZHAO ; Jianbin XIAO ; Weifeng TU ; Jiaze SUN ; Yuting DUAN ; Bao WANG
Journal of Southern Medical University 2025;45(8):1800-1808
Objective To explore the efficacy of DSA-guided intrathecal drug delivery system combined with Zi Wu Liu Zhu Acupoint Therapy for management of cancer pain and provide reference for its standardized clinical application.Methods and Results Recommendations were formulated based on literature review and expert group discussion,and consensus was reached following expert consultation.The consensus recommendations are comprehensive,covering the entire treatment procedures from preoperative assessment and preparation,surgical operation process,postoperative management and traditional Chinese medicine treatment to individualized treatment planning.The study results showed that the treatment plans combining traditional Chinese with Western medicine effectively alleviated cancer pain,reduced the use of opioid drugs,and significantly improved the quality of life and enhanced immune function of the patients.Postoperative follow-up suggested good treatment tolerance among the patients without serious complications.Conclusion The formulated consensus is comprehensive and can provide reference for clinicians to use DSA-guided intrathecal drug delivery system combined with Zi Wu Liu Zhu Acupoint Therapy.The combined treatment has a high clinical value with a good safety profile for management of cancer pain.
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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