1.Inhibition of HDAC3 Promotes Psoriasis Development in Mice Through Regulating Th17
Fan XU ; Xin-Rui ZHANG ; Yang-Chen XIA ; Wen-Ting LI ; Hao CHEN ; An-Qi QIN ; Ai-Hong ZHANG ; Yi-Ran ZHU ; Feng TIAN ; Quan-Hui ZHENG
Progress in Biochemistry and Biophysics 2025;52(4):1008-1017
ObjectiveTo investigate the influence of histone deacetylase 3 (HDAC3) on the occurrence, development of psoriasis-like inflammation in mice, and the relative immune mechanisms. MethodsHealthy C57BL/6 mice aged 6-8 weeks were selected and randomly divided into 3 groups: control group (Control), psoriasis model group (IMQ), and HDAC3 inhibitor RGFP966-treated psoriasis model group (IMQ+RGFP966). One day prior to the experiment, the back hair of the mice was shaved. After a one-day stabilization period, the mice in Control group was treated with an equal amount of vaseline, while the mice in IMQ group was treated with imiquimod (62.5 mg/d) applied topically on the back to establish a psoriasis-like inflammation model. The mice in IMQ+RGFP966 group received intervention with a high dose of the HDAC3-selective inhibitor RGFP966 (30 mg/kg) based on the psoriasis-like model. All groups were treated continuously for 5 d, during which psoriasis-like inflammation symptoms (scaling, erythema, skin thickness), body weight, and mental status were observed and recorded, with photographs taken for documentation. After euthanasia, hematoxylin-eosin (HE) staining was used to assess the effect of RGFP966 on the skin tissue structure of the mice, and skin thickness was measured. The mRNA and protein expression levels of HDAC3 in skin tissues were detected using reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot (WB), respectively. Flow cytometry was employed to analyze neutrophils in peripheral blood and lymph nodes, CD4+ T lymphocytes, CD8+ T lymphocytes in peripheral blood, and IL-17A secretion by peripheral blood CD4+ T lymphocytes. Additionally, spleen CD4+ T lymphocyte expression of HDAC3, CCR6, CCR8, and IL-17A secretion levels were analyzed. Immunohistochemistry was used to detect the localization and expression levels of HDAC3, IL-17A, and IL-10 in skin tissues. ResultsCompared with the Control group, the IMQ group exhibited significant psoriasis-like inflammation, characterized by erythema, scaling, and skin wrinkling. Compared with the IMQ group, RGFP966 exacerbated psoriasis-like inflammatory symptoms, leading to increased hyperkeratosis. The psoriasis area and severity index (PASI) skin symptom scores were higher in the IMQ group than those in the Control group, and the scores were further elevated in the IMQ+RGFP966 group compared to the IMQ group. Skin thickness measurements showed a trend of IMQ+RGFP966>IMQ>Control. The numbers of neutrophils in the blood and lymph nodes increased sequentially in the Control, IMQ, and IMQ+RGFP966 groups, with a similar trend observed for CD4+ and CD8+ T lymphocytes in the blood. In skin tissues, compared with the Control group, the mRNA and protein levels of HDAC3 decreased in the IMQ group, but RGFP966 did not further reduce these expressions. HDAC3 was primarily located in the nucleus. Compared with the Control group, the nuclear HDAC3 content decreased in the skin tissues of the IMQ group, and RGFP966 further reduced nuclear HDAC3. Compared with the Control and IMQ groups, RGFP966 treatment decreased HDAC3 expression in splenic CD4+ and CD8+ T cells. RGFP966 treatment increased the expression of CCR6 and CCR8 in splenic CD4+ T cells and enhanced IL-17A secretion by peripheral blood and splenic CD4+ T lymphocytes. Additionally, compared with the IMQ group, RGFP966 reduced IL-10 protein levels and upregulated IL-17A expression in skin tissues. ConclusionRGFP966 exacerbates psoriatic-like inflammatory responses by inhibiting HDAC3, increasing the secretion of the cytokine IL-17A, and upregulating the expression of chemokines CCR8 and CCR6.
2.Research progress in mechanisms of kidney-tonifying traditional Chinese medicine in promoting healing of osteoporotic fractures.
Jun WU ; Ou-Ye LI ; Ken QIN ; Xuan WAN ; Wang-Bing XU ; Yong LI ; Jia-Wei ZHONG ; Yong-Xiang YE ; Rui XU
China Journal of Chinese Materia Medica 2025;50(15):4166-4177
Osteoporotic fractures(OPF) refer to the fractures caused by minor violence in the state of osteoporosis, seriously threatening the life and health of elderly patients. Drug and surgical therapies have limitations such as single targets, diverse adverse reactions, and poor prognosis. Kidney-tonifying traditional Chinese medicine(TCM) has good potential in the treatment of OPF. TCM can promote the healing of OPF by promoting angiogenesis in the early stage of bone healing, promoting osteogenic differentiation of bone marrow mesenchymal stem cells in the stage of bone repair, maintaining the balance of osteogenic and osteoclastic system in the stage of bone remodeling, and regulating the oxidative stress responses throughout the process of OPF healing. TCM can alleviate the pathological state of osteoporosis and promote fracture healing in OPF patients via multiple pathways and targets, demonstrating the advantages and potential of biphasic regulation.
Humans
;
Drugs, Chinese Herbal/therapeutic use*
;
Osteoporotic Fractures/metabolism*
;
Animals
;
Fracture Healing/drug effects*
;
Medicine, Chinese Traditional
;
Kidney/metabolism*
;
Osteogenesis/drug effects*
3.Machine learning models established to distinguish OA and RA based on immune factors in the knee joint fluid.
Qin LIANG ; Lingzhi ZHAO ; Yan LU ; Rui ZHANG ; Qiaolin YANG ; Hui FU ; Haiping LIU ; Lei ZHANG ; Guoduo LI
Chinese Journal of Cellular and Molecular Immunology 2025;41(4):331-338
Objective Based on 25 indicators including immune factors, cell count classification, and smear results of the knee joint fluid, machine learning models were established to distinguish between osteoarthritis (OA) and rheumatoid arthritis (RA). Methods 100 OA and 40 RA patients scheduled for total knee arthroplasty were enrolled respectively. Each patient's knee joint fluid was collected preoperatively. Nucleated cells were counted and classified. The expression levels of immune factors, including tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), IL-6, IL-8, IL-15, matrix metalloproteinase 3 (MMP3), MMP9, MMP13, rheumatoid factor (RF), serum amyloid A (SAA), C-reactive protein (CRP), and others were measured. Smears and microscopic classification of all the immune factors were performed. Independent influencing factors for OA or RA were identified using univariate binary logistic regression, Lasso regression, and multivariate binary logistic regression. Based on the independent influencing factors, three machine learning models were constructed which are logistic regression, random forest, and support vector machine. Receiver operating characteristic curve (ROC), calibration curve and decision curve analysis (DCA) were used to evaluate and compare the models. Results A total of 5 indicators in the knee joint fluid were screened out to distinguish OA and RA, which were IL-1β(odds ratio(OR)=10.512, 95× confidence interval (95×CI) was 1.048-105.42, P=0.045), IL-6 (OR=1.007, 95×CI was 1.001-1.014, P=0.022), MMP9 (OR=3.202, 95×CI was 1.235-8.305, P=0.017), MMP13 (OR=1.002, 95× CI was 1-1.004, P=0.049), and RF (OR=1.091, 95×CI was 1.01-1.179, P=0.026). According to the results of ROC, calibration curve and DCA, the accuracy (0.979), sensitivity (0.98) and area under the curve (AUC, 0.996, 95×CI was 0.991-1) of the random forest model were the highest. It has good validity and feasibility, and its distinguishing ability is better than the other two models. Conclusion The machine learning model based on immune factors in the knee joint fluid holds significant value in distinguishing OA and RA. It provides an important reference for the clinical early differential diagnosis, prevention and treatment of OA and RA.
Humans
;
Arthritis, Rheumatoid/metabolism*
;
Machine Learning
;
Male
;
Female
;
Middle Aged
;
Aged
;
Synovial Fluid/immunology*
;
Osteoarthritis, Knee/metabolism*
;
Knee Joint/metabolism*
;
ROC Curve
;
Diagnosis, Differential
4.Chain mediating role of family care and emotional management between social support and anxiety in primary school students.
Zhan-Wen LI ; Jian-Hui WEI ; Ke-Bin CHEN ; Xiao-Rui RUAN ; Yu-Ting WEN ; Cheng-Lu ZHOU ; Jia-Peng TANG ; Ting-Ting WANG ; Ya-Qing TAN ; Jia-Bi QIN
Chinese Journal of Contemporary Pediatrics 2025;27(10):1176-1184
OBJECTIVES:
To investigate the chain mediating role of family care and emotional management in the relationship between social support and anxiety among rural primary school students.
METHODS:
A questionnaire survey was conducted among students in grades 4 to 6 from four counties in Hunan Province. Data were collected using the Social Support Rating Scale, Family Care Index Scale, Emotional Intelligence Scale, and Generalized Anxiety Disorder -7. Logistic regression analysis was used to explore the influencing factors of anxiety symptoms. Mediation analysis was conducted to assess the chain mediating effects of family care and emotional management between social support and anxiety.
RESULTS:
A total of 4 141 questionnaires were distributed, with 3 874 valid responses (effective response rate: 93.55%). The prevalence rate of anxiety symptoms among these students was 9.32% (95%CI: 8.40%-10.23%). Significant differences were observed in the prevalence rates of anxiety symptoms among groups with different levels of social support, family functioning, and emotional management ability (P<0.05). The total indirect effect of social support on anxiety symptoms via family care and emotional management was significant (β=-0.137, 95%CI: -0.167 to -0.109), and the direct effect of social support on anxiety symptoms remained significant (P<0.05). Family care and emotional management served as significant chain mediators in the relationship between social support and anxiety symptoms (β=-0.025,95%CI:-0.032 to -0.018), accounting for 14.5% of the total effect.
CONCLUSIONS
Social support can directly affect anxiety symptoms among rural primary school students and can also indirectly influence anxiety symptoms through the chain mediating effects of family care and emotional management. These findings provide scientific evidence for the prevention of anxiety in primary school students from multiple perspectives.
Humans
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Female
;
Male
;
Social Support
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Anxiety/etiology*
;
Child
;
Students/psychology*
;
Emotions
;
Logistic Models
5.Diagnostic value of ultrasonic shear wave elastography for clinically significant prostate cancer.
Fang-Rui YANG ; Yong-Hao JI ; Li-Tao RUAN ; Jian-Xue LIU ; Yao-Ren ZHANG ; Xiao ZHANG ; Qin-Yun WAN ; Si-Fan REN
National Journal of Andrology 2025;31(6):505-511
OBJECTIVE:
To explore the diagnostic value of shear wave elastography (SWE) for clinically significant prostate cancer (csPCa).
METHODS:
We retrospectively analyzed the clinical data of 359 cases with suspected prostate cancer (PCa) in Baoji Central Hospital from June 2017 to July 2023. All the patients underwent the following examinations in the order of serum prostate-specific antigen (PSA) testing, transrectal ultrasonography (TRUS), measurement of the stiffness of the entire prostate gland by SWE, and TRUS-guided prostate puncture biopsy. The stiffness of the entire prostate gland was defined as the average of Young's modulus at both sides of the base, middle, and apex of the prostate, including the maximum Young's modulus (Emax), mean Young's modulus (Emean), and minimum Young's modulus (Emin). We analyzed the correlation of the parameters of the stiffness of the entire prostate gland with the pathological results, focusing on their diagnostic performance for csPCa.
RESULTS:
Of the 359 cases, 189 were diagnosed by pathological puncture biopsy as BPH, 26 as non-csPCa, and 144 as csPCa. The PSA level, Emax, Emean and Emin were significantly higher in the csPCa than those in the BPH and non-csPCa groups (all P < 0.01), but showed no statistically significant difference between the BPH and non-csPCa groups (all P > 0.05). The area under the receiver operating characteristic curve (AUC), optimal cut-off value, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of Emax in the diagnosis of csPCa were 0.852, 143.92 kPa, 72.22%, 84.65%, 75.91%, 81.98% and 79.67%; those of Emean were 0.868, 82.42 kPa, 67.36%, 91.16%, 83.62%, 80.66% and 81.62%; and those of Emin were 0.682, 32.73 kPa, 47.22%, 89.30%, 73.91%, 71.54% and 72.14%, respectively. In the non-csPCa group, Emax, Emean and Emin were found below the optimal cut-off value in 73.08% (19/26), 92.31% (24/26) and 88.46% (23/26), respectively.
CONCLUSION
The stiffness of the entire prostate gland measured by SWE contributes to the diagnosis of csPCa, reduces unnecessary detection of non-csPCa, and provides some reference for its active surveillance.
Humans
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Male
;
Prostatic Neoplasms/diagnosis*
;
Elasticity Imaging Techniques
;
Retrospective Studies
;
Prostate/pathology*
;
Prostate-Specific Antigen/blood*
;
Aged
;
Middle Aged
6.Liang-Ge-San Decoction Ameliorates Acute Respiratory Distress Syndrome via Suppressing p38MAPK-NF-κ B Signaling Pathway.
Quan LI ; Juan CHEN ; Meng-Meng WANG ; Li-Ping CAO ; Wei ZHANG ; Zhi-Zhou YANG ; Yi REN ; Jing FENG ; Xiao-Qin HAN ; Shi-Nan NIE ; Zhao-Rui SUN
Chinese journal of integrative medicine 2025;31(7):613-623
OBJECTIVE:
To explore the potential effects and mechanisms of Liang-Ge-San (LGS) for the treatment of acute respiratory distress syndrome (ARDS) through network pharmacology analysis and to verify LGS activity through biological experiments.
METHODS:
The key ingredients of LGS and related targets were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform. ARDS-related targets were selected from GeneCards and DisGeNET databases. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed using the Metascape Database. Molecular docking analysis was used to confirm the binding affinity of the core compounds with key therapeutic targets. Finally, the effects of LGS on key signaling pathways and biological processes were determined by in vitro and in vivo experiments.
RESULTS:
A total of LGS-related targets and 496 ARDS-related targets were obtained from the databases. Network pharmacological analysis suggested that LGS could treat ARDS based on the following information: LGS ingredients luteolin, wogonin, and baicalein may be potential candidate agents. Mitogen-activated protein kinase 14 (MAPK14), recombinant V-Rel reticuloendotheliosis viral oncogene homolog A (RELA), and tumor necrosis factor alpha (TNF-α) may be potential therapeutic targets. Reactive oxygen species metabolic process and the apoptotic signaling pathway were the main biological processes. The p38MAPK/NF-κ B signaling pathway might be the key signaling pathway activated by LGS against ARDS. Moreover, molecular docking demonstrated that luteolin, wogonin, and baicalein had a good binding affinity with MAPK14, RELA, and TNF α. In vitro experiments, LGS inhibited the expression and entry of p38 and p65 into the nucleation in human bronchial epithelial cells (HBE) cells induced by LPS, inhibited the inflammatory response and oxidative stress response, and inhibited HBE cell apoptosis (P<0.05 or P<0.01). In vivo experiments, LGS improved lung injury caused by ligation and puncture, reduced inflammatory responses, and inhibited the activation of p38MAPK and p65 (P<0.05 or P<0.01).
CONCLUSION
LGS could reduce reactive oxygen species and inflammatory cytokine production by inhibiting p38MAPK/NF-κ B signaling pathway, thus reducing apoptosis and attenuating ARDS.
Drugs, Chinese Herbal/pharmacology*
;
Respiratory Distress Syndrome/enzymology*
;
p38 Mitogen-Activated Protein Kinases/metabolism*
;
NF-kappa B/metabolism*
;
Animals
;
Signal Transduction/drug effects*
;
Molecular Docking Simulation
;
Humans
;
Male
;
Network Pharmacology
;
Apoptosis/drug effects*
;
Mice
7.Rutaecarpine Attenuates Monosodium Urate Crystal-Induced Gouty Inflammation via Inhibition of TNFR-MAPK/NF-κB and NLRP3 Inflammasome Signaling Pathways.
Min LI ; Zhu-Jun YIN ; Li LI ; Yun-Yun QUAN ; Ting WANG ; Xin ZHU ; Rui-Rong TAN ; Jin ZENG ; Hua HUA ; Qin-Xuan WU ; Jun-Ning ZHAO
Chinese journal of integrative medicine 2025;31(7):590-599
OBJECTIVE:
To investigate the anti-inflammatory effect of rutaecarpine (RUT) on monosodium urate crystal (MSU)-induced murine peritonitis in mice and further explored the underlying mechanism of RUT in lipopolysaccharide (LPS)/MSU-induced gout model in vitro.
METHODS:
In MSU-induced mice, 36 male C57BL/6 mice were randomly divided into 6 groups of 8 mice each group, including the control group, model group, RUT low-, medium-, and high-doses groups, and prednisone acetate group. The mice in each group were orally administered the corresponding drugs or vehicle once a day for 7 consecutive days. The gout inflammation model was established by intraperitoneal injection of MSU to evaluate the anti-gout inflammatory effects of RUT. Then the proinflammatory cytokines were measured by enzyme-linked immunosorbent assay (ELISA) and the proportions of infiltrating neutrophils cytokines were detected by flow cytometry. In LPS/MSU-treated or untreated THP-1 macrophages, cell viability was observed by cell counting kit 8 and proinflammatory cytokines were measured by ELISA. The percentage of pyroptotic cells were detected by flow cytometry. Respectively, the mRNA and protein levels were measured by real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot, the nuclear translocation of nuclear factor κB (NF-κB) p65 was observed by laser confocal imaging. Additionally, surface plasmon resonance (SPR) and molecular docking were applied to validate the binding ability of RUT components to tumor necrosis factor α (TNF-α) targets.
RESULTS:
RUT reduced the levels of infiltrating neutrophils and monocytes and decreased the levels of the proinflammatory cytokines interleukin 1β (IL-1β) and interleukin 6 (IL-6, all P<0.01). In vitro, RUT reduced the production of IL-1β, IL-6 and TNF-α. In addition, RT-PCR revealed the inhibitory effects of RUT on the mRNA levels of IL-1β, IL-6, cyclooxygenase-2 and TNF-α (P<0.05 or P<0.01). Mechanistically, RUT markedly reduced protein expressions of tumor necrosis factor receptor (TNFR), phospho-mitogen-activated protein kinase (p-MAPK), phospho-extracellular signal-regulated kinase, phospho-c-Jun N-terminal kinase, phospho-NF-κB, phospho-kinase α/β, NOD-like receptor thermal protein domain associated protein 3 (NLRPS), cleaved-cysteinyl aspartate specific proteinase-1 and cleaved-gasdermin D in macrophages (P<0.05 or P<0.01). Molecularly, SPR revealed that RUT bound to TNF-α with a calculated equilibrium dissociation constant of 31.7 µmol/L. Molecular docking further confirmed that RUT could interact directly with the TNF-α protein via hydrogen bonding, van der Waals interactions, and carbon-hydrogen bonding.
CONCLUSION
RUT alleviated MSU-induced peritonitis and inhibited the TNFR1-MAPK/NF-κB and NLRP3 inflammasome signaling pathway to attenuate gouty inflammation induced by LPS/MSU in THP-1 macrophages, suggesting that RUT could be a potential therapeutic candidate for gout.
Animals
;
NF-kappa B/metabolism*
;
Male
;
Indole Alkaloids/therapeutic use*
;
Signal Transduction/drug effects*
;
Mice, Inbred C57BL
;
Inflammation/complications*
;
Uric Acid
;
Quinazolines/therapeutic use*
;
NLR Family, Pyrin Domain-Containing 3 Protein/metabolism*
;
Humans
;
Gout/chemically induced*
;
Inflammasomes/metabolism*
;
Cytokines/metabolism*
;
THP-1 Cells
;
Mitogen-Activated Protein Kinases/metabolism*
;
Mice
;
Molecular Docking Simulation
;
Lipopolysaccharides
;
Quinazolinones
8.Monotropein Induced Apoptosis and Suppressed Cell Cycle Progression in Colorectal Cancer Cells.
Quan GAO ; Lin LI ; Qi-Man ZHANG ; Qin-Song SHENG ; Ji-Liang ZHANG ; Li-Jun JIN ; Rui-Yan SHANG
Chinese journal of integrative medicine 2024;30(1):25-33
OBJECTIVE:
To determine whether monotropein has an anticancer effect and explore its potential mechanisms against colorectal cancer (CRC) through network pharmacology and molecular docking combined with experimental verification.
METHODS:
Network pharmacology and molecular docking were used to predict potential targets of monotropein against CRC. Cell counting kit assay, plate monoclonal assay and microscopic observation were used to investigate the antiproliferative effects of monotropein on CRC cells HCT116, HT29 and LoVo. Flow cytometry and scratch assay were used to analyze apoptosis and cell cycle, as well as cell migration, respectively in HCT116, HT29, and LoVo cells. Western blotting was used to detect the expression of proteins related to apoptosis, cell cycle, and cell migration, and the expression of proteins key to the Akt pathway.
RESULTS:
The Gene Ontology and Reactome enrichment analyses indicated that the anticancer potential of monotropein against CRC might be involved in multiple cancer-related signaling pathways. Among these pathways, RAC-beta serine/threonine-protein kinase (Akt1, Akt2), cyclin-dependent kinase 6 (CDK6), matrix metalloproteinase-9 (MMP9), epidermal growth factor receptor (EGFR), cell division control protein 42 homolog (CDC42) were shown as the potential anticancer targets of monotropein against CRC. Molecular docking suggested that monotropein may interact with the 6 targets (Akt1, Akt2, CDK6, MMP9, EGFR, CDC42). Subsequently, cell activity of HCT116, HT29 and LoVo cell lines were significantly suppressed by monotropein (P<0.05). Furthermore, our research revealed that monotropein induced cell apoptosis by inhibiting Bcl-2 and increasing Bax, induced G1-S cycle arrest in colorectal cancer by decreasing the expressions of CyclinD1, CDK4 and CDK6, inhibited cell migration by suppressing the expressions of CDC42 and MMP9 (P<0.05), and might play an anticancer role through Akt signaling pathway.
CONCLUSION
Monotropein exerts its antitumor effects primarily by arresting the cell cycle, causing cell apoptosis, and inhibiting cell migration. This indicates a high potential for developing novel medication for treating CRC.
Humans
;
Proto-Oncogene Proteins c-akt/metabolism*
;
Cell Proliferation
;
Matrix Metalloproteinase 9
;
Molecular Docking Simulation
;
Cell Cycle
;
ErbB Receptors
;
Apoptosis
;
Colorectal Neoplasms/pathology*
;
Cell Line, Tumor
9.Structure-based development of potent and selective type-II kinase inhibitors of RIPK1.
Ying QIN ; Dekang LI ; Chunting QI ; Huaijiang XIANG ; Huyan MENG ; Jingli LIU ; Shaoqing ZHOU ; Xinyu GONG ; Ying LI ; Guifang XU ; Rui ZU ; Hang XIE ; Yechun XU ; Gang XU ; Zheng ZHANG ; Shi CHEN ; Lifeng PAN ; Ying LI ; Li TAN
Acta Pharmaceutica Sinica B 2024;14(1):319-334
Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) functions as a key regulator in inflammation and cell death and is involved in mediating a variety of inflammatory or degenerative diseases. A number of allosteric RIPK1 inhibitors (RIPK1i) have been developed, and some of them have already advanced into clinical evaluation. Recently, selective RIPK1i that interact with both the allosteric pocket and the ATP-binding site of RIPK1 have started to emerge. Here, we report the rational development of a new series of type-II RIPK1i based on the rediscovery of a reported but mechanistically atypical RIPK3i. We also describe the structure-guided lead optimization of a potent, selective, and orally bioavailable RIPK1i, 62, which exhibits extraordinary efficacies in mouse models of acute or chronic inflammatory diseases. Collectively, 62 provides a useful tool for evaluating RIPK1 in animal disease models and a promising lead for further drug development.
10.Endo-beta-N-acetylglucosaminidase: Possible Functions and Mechanisms
Xin-Rong LU ; Yong-Liang TONG ; Wei-Li KONG ; Lin ZOU ; Dan-Feng SHEN ; Shao-Xian LÜ ; Rui-Jie LIU ; Shao-Xing ZHANG ; Yu-Xin ZHANG ; Lin-Lin HOU ; Gui-Qin SUN ; Li CHEN
Progress in Biochemistry and Biophysics 2024;51(5):985-999
Endo-beta-N-acetylglucosaminidase (ENGase) is widely distributed in various organisms. The first reported ENGase activity was detected in Diplococcus pneumoniae in 1971. The protein (Endo D) was purified and its peptide sequence was determined in 1974. Three ENGases (Endo F1-F3) were discovered in Flavobacterium meningosepticum from 1982 to 1993. After that, the activity was detected from different species of bacteria, yeast, fungal, plant, mice, human, etc. Multiple ENGases were detected in some species, such as Arabidopsis thaliana and Trichoderma atroviride. The first preliminary crystallographic analysis of ENGase was conducted in 1994. But to date, only a few ENGases structures have been obtained, and the structure of human ENGase is still missing. The currently identified ENGases were distributed in the GH18 or GH85 families in Carbohydrate-Active enZyme (CAZy) database. GH18 ENGase only has hydrolytic activity, but GH85 ENGase has both hydrolytic and transglycosylation activity. Although ENGases of the two families have similar (β/α)8-TIM barrel structures, the active sites are slightly different. ENGase is an effective tool for glycan detection andglycan editing. Biochemically, ENGase can specifically hydrolyze β‑1,4 glycosidic bond between the twoN-acetylglucosamines (GlcNAc) on core pentasaccharide presented on glycopeptides and/or glycoproteins. Different ENGases may have different substrate specificity. The hydrolysis products are oligosaccharide chains and a GlcNAc or glycopeptides or glycoproteins with a GlcNAc. Conditionally, it can use the two products to produce a new glycopeptides or glycoprotein. Although ENGase is a common presentation in cell, its biological function remains unclear. Accumulated evidences demonstrated that ENGase is a none essential gene for living and a key regulator for differentiation. No ENGase gene was detected in the genomes of Saccharomyces cerevisiae and three other yeast species. Its expression was extremely low in lung. As glycoproteins are not produced by prokaryotic cells, a role for nutrition and/or microbial-host interaction was predicted for bacterium produced enzymes. In the embryonic lethality phenotype of the Ngly1-deficient mice can be partially rescued by Engase knockout, suggesting down regulation of Engase might be a solution for stress induced adaptation. Potential impacts of ENGase regulation on health and disease were presented. Rabeprazole, a drug used for stomach pain as a proton inhibitor, was identified as an inhibitor for ENGase. ENGases have been applied in vitro to produce antibodies with a designated glycan. The two step reactions were achieved by a pair of ENGase dominated for hydrolysis of substrate glycoprotein and synthesis of new glycoprotein with a free glycan of designed structure, respectively. In addition, ENGase was also been used in cell surface glycan editing. New application scenarios and new detection methods for glycobiological engineering are quickly opened up by the two functions of ENGase, especially in antibody remodeling and antibody drug conjugates. The discovery, distribution, structure property, enzymatic characteristics and recent researches in topical model organisms of ENGase were reviewed in this paper. Possible biological functions and mechanisms of ENGase, including differentiation, digestion of glycoproteins for nutrition and stress responding were hypothesised. In addition, the role of ENGase in glycan editing and synthetic biology was discussed. We hope this paper may provide insights for ENGase research and lay a solid foundation for applied and translational glycomics.

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