1.Effect of Oral Sodium Butyrate on Skeletal Muscle Atrophy via The Gut-muscle Axis in Antibiotic-pretreated CT26 Tumor-bearing Mice and Its Mechanism
Shu-Ling ZHANG ; Jun-Wei WANG ; Shi-Liang HU ; Tu-Tu WANG ; Shun-Chang LI ; Jia FAN ; Jun-Zhi SUN
Progress in Biochemistry and Biophysics 2026;53(3):724-739
ObjectiveTo explore the effect of oral sodium butyrate on skeletal muscle atrophy in CT26 tumor mice through the gut microbiota-skeletal muscle axis and its potential mechanism. MethodsSixty SPF BALB/c male mice aged 8 weeks were randomly divided into a normal control group (NC, n=18) and a ABX-depleted group (ABX, n=42). The ABX mice were pretreated with a quadruple antibiotic cocktail via oral gavage (0.2 ml per administration, once daily, 6 d per week, for 2 weeks), whereas NC received an equal volume of sterile water. The quadruple antibiotic cocktail consisted of metronidazole (1 g/L), vancomycin (0.5 g/L), ampicillin (1 g/L), and gentamicin (1 g/L). Following successful pretreatment, six mice from each group were randomly selected for gut microbiota sequencing analysis and designated as the Abx group and the NC0 group, respectively. Theremaining mice in ABX were subcutaneously inoculated in the dorsum with 0.2 ml of CT26 cell suspension (at a cell density of 1×107/ml). Then these mice were randomly allocated into three subgroups: a control tumor bearing model group (0_NaB, n=12), a tumor-bearing model group receiving low-dose oral sodium butyrate (L_NaB, n=12), a tumor-bearing model group receiving high-dose oral sodium butyrate (H_NaB, n=12). And mice in NC were inoculated at the same site with 0.2 ml of normal saline. The administration dose for L_NaB was 0.3 g/(kg·d), that for H_NaB was 0.5 g/(kg·d), while NC and 0_NaB were given the same volume of normal saline (0.2ml per time, once daily, 6 d per week, for 4 weeks). The general condition of mice was monitored, and forelimb grip strength gastrocnemius muscle mass and its muscle fiber cross-sectional area were measured for each group. The structural changes in gut microbiota were assessed by 16S rRNA sequencing of cecal contents. Pathological alterations in the intestinal wall were examined via HE staining. Serum and gastrocnemius muscle levels of TNF‑α, IL-6, IL-1β, and LPS were quantified using ELISA. The protein expression of ZO-1 and occludin in the small intestine, as well as proteins associated with the TLR4/MyD88/NF-κB signaling pathway in the gastrocnemius muscle, were detected by Western blot analysis. Results(1) The alpha-diversity in Abx was significantly lower than that in NC0 (P<0.01), a significant decrease of the mass and muscle fiber cross-sectional area of the gastrocnemius (P<0.01), with the majority of gut microbiota being effectively depleted. (2) Compared with NC, the subcutaneous tumors of mice in 0_NaB were prominent, a significant increase of the mass and muscle fiber cross-sectional area of the gastrocnemius, accompanied by a significant decrease in body weight at the end of the 3th and 4th week (P<0.05), and a significant weakening of the forelimb grasping strength at the 5th and 6th week (P<0.01). Compared with 0_NaB, the tumor mass of mice in L_NaB and H_NaB showed a significant decreasing trend, and the grip strength of the forelimbs significantly increased at the 5th and 6th week (P<0.05, P<0.01). (3) Compared with 0_NaB, the Shannon and Observed species indices in α diversity of L_NaB and H_NaB were significantly increased (P<0.05). At the genus level, compared with 0_NaB, L_NaB exhibited a significant decrease in the relative abundance of Parasutterella (P< 0.01), while H_NaB showed significant reductions in the relative abundances of both Escherichia-Shigella and Parasutterella (P < 0.01). (4) Compared with 0_NaB, the small intestinal tissue structure in L_NaB and H_NaB was more intact, the infiltration of inflammatory cells was significantly reduced, and the capillaries were slightly dilated. The expression levels of ZO-1 and occludin proteins in L_NaB were significantly increased (P<0.01). (5) The LPS concentration in the gastrocnemius muscle and the protein expression levels of TLR4, MyD88, p-IκBα, and p-NF‑κB p65 in L_NaB and H_NaB were significantly lower than those in 0_NaB (P<0.05). The serum TNF‑α concentration in H_NaB and TNF-α concentration in the gastrocnemius muscle of the L_NaB and H_NaB were significantly lower than those in 0_NaB (P<0.05, P<0.01, P<0.01). ConclusionOral administration of NaB can improve gut microbiota α diversity, adjusting its composition, improving intestinal mucosal barrier function, reducing the LPS-induced pro-inflammatory response, and delaying skeletal muscle atrophy. The underlying mechanism may involve down regulation of TLR4/MyD88/NF-κB signaling in skeletal muscle.
2.Update on the treatment navigation for functional cure of chronic hepatitis B: Expert consensus 2.0
Di WU ; Jia-Horng KAO ; Teerha PIRATVISUTH ; Xiaojing WANG ; Patrick T.F. KENNEDY ; Motoyuki OTSUKA ; Sang Hoon AHN ; Yasuhito TANAKA ; Guiqiang WANG ; Zhenghong YUAN ; Wenhui LI ; Young-Suk LIM ; Junqi NIU ; Fengmin LU ; Wenhong ZHANG ; Zhiliang GAO ; Apichat KAEWDECH ; Meifang HAN ; Weiming YAN ; Hong REN ; Peng HU ; Sainan SHU ; Paul Yien KWO ; Fu-sheng WANG ; Man-Fung YUEN ; Qin NING
Clinical and Molecular Hepatology 2025;31(Suppl):S134-S164
As new evidence emerges, treatment strategies toward the functional cure of chronic hepatitis B are evolving. In 2019, a panel of national hepatologists published a Consensus Statement on the functional cure of chronic hepatitis B. Currently, an international group of hepatologists has been assembled to evaluate research since the publication of the original consensus, and to collaboratively develop the updated statements. The 2.0 Consensus was aimed to update the original consensus with the latest available studies, and provide a comprehensive overview of the current relevant scientific literatures regarding functional cure of hepatitis B, with a particular focus on issues that are not yet fully clarified. These cover the definition of functional cure of hepatitis B, its mechanisms and barriers, the effective strategies and treatment roadmap to achieve this endpoint, in particular new surrogate biomarkers used to measure efficacy or to predict response, and the appropriate approach to pursuing a functional cure in special populations, the development of emerging antivirals and immunomodulators with potential for curing hepatitis B. The statements are primarily intended to offer international guidance for clinicians in their practice to enhance the functional cure rate of chronic hepatitis B.
3.Analysis of China's cross-regional medical insurance settlement policy based on policy tools
Shi-qiang WANG ; Hui WANG ; Shu ZHANG ; Zi-qi ZHANG ; Yi-jie LI ; Jia-yi LIU ; Guo-heng HU
Chinese Journal of Health Policy 2025;18(10):32-39
Objective:Systematically review the release status and characteristics of policies related to cross-regional medical insurance settlement policies in China,providing reference for promoting the convenience of medical insurance settlement services and improving management efficiency.Methods:Using content analysis,a two-dimensional framework of"policy objectives-policy tools"was constructed.A total of 127 policy documents were coded and analyzed.Results:Demand-based tools were applied most frequently(43.6%),followed by environmental and supply-based tools.Policy objectives mainly focused on improving service convenience,supported by expanding coverage and ensuring regulatory security.Conclusions:China's cross-regional medical insurance settlement policies have improved service accessibility and strengthened institutional supervision while gradually expanding coverage.However,deficiencies remain in assessment refinement and emergency mechanisms.Greater interdepartmental coordination is needed to enhance regulatory linkage and ensure the safe operation of medical insurance funds.
4.Promotive effect of hypoxia-induced ANGPTL4 expression on experimental choroidal neovascularization
Jia CHEN ; Ying YANG ; Shu SU ; Shenglai ZHANG ; Xiaowei YANG ; Aimin SANG
Chinese Journal of Experimental Ophthalmology 2025;43(10):906-914
Objective:To investigate the role of hypoxia-induced angiopoietin-like protein 4 (ANGPTL4) expression in experimental choroidal neovascularization (CNV).Methods:Twenty-seven SPF male C57BL/6J mice aged 6-8 weeks were selected.Eighteen of the mice were used to establish a laser-induced CNV model.On the 7th day after laser photocoagulation, success of the modeling was verified using optical coherence tomography angiography (OCTA) and fundus fluorescein angiography (FFA). The retinal pigment epithelium (RPE)-choroid-sclera complex was extracted for protein analysis before modeling and on the 3rd and 7th days after modeling.The relative expression levels of ANGPTL4 and vascular endothelial growth factor (VEGF) at different time points were detected by Western blot.Additionally, frozen sections of mouse eyeballs on day 7 after modeling were prepared and the expression and cellular localization of ANGPTL4 were observed by immunofluorescence.RF/6A cells, derived from monkey choroidal retinal endothelial cells, were treated with 200 μmol/L cobalt chloride (CoCl 2) in the culture medium for 0, 3, 6, and 12 hours.RF/6A cells were also divided into a normal control group, a hypoxia group, and a hypoxia+ si-ANGPTL4 group, and cells were transfected with a plasmid containing si-ANGPTL4 sequence.The relative expression levels of ANGPTL4 and VEGF proteins in each group were detected by Western blot, and the differences in tube formation among the groups were observed by tube formation assay.A total of 27 male C57BL/6J mice were randomly divided into CNV group, CNV+ si-NC group, and CNV+ si-ANGPTL4 group, with 9 mice in each group.In the CNV+ si-NC and CNV+ si-ANGPTL4 groups, si-NC and si-ANGPTL4 were respectively injected into the vitreous cavity after the CNV model was established.Fluorescence leakage in mice was observed by FFA, and the length, thickness and area of CNV was observed using OCTA and immunofluorescence staining of choroidal flat mounts.The relative expression levels of ANGPTL4 and VEGF proteins in each group were detected by Western blot.All animal experiments were conducted in accordance with ARVO Statement on the Use of Animals in Ophthalmic and Vision Research.The experimental protocol was approved by the Affiliated Hospital of Nantong University (No.S20220822-902). Results:Before modeling and on the 3rd and 7th days after modeling, the relative expression levels of ANGPTL4 protein were 1.00±0.00, 1.58±0.05, and 1.90±0.04, respectively, and the relative expression levels of VEGF protein were 1.00±0.00, 1.31±0.05, and 1.84±0.04, respectively, with statistically significant overall differences ( F=528.934, 390.424, both P<0.05). Among them, on the 3rd and 7th days after modeling, the relative expression levels of ANGPTL4 and VEGF proteins were significantly higher in CNV group than in the control group (all P<0.05). The tissues of each layer of the retina were clear in the control group, while neovascularization could be seen growing under the retinal neuroepithelial layer in the CNV group.Compared with the control group, ANGPTL4 expression was significantly increased and colocalized with vascular endothelial cells in the CNV group.After CoCl 2 treatment of RF/6A cells for 3, 6, and 12 hours, the relative expression levels of ANGPTL4 and VEGF proteins were higher than at 0 hour, with statistically significant differences (all P<0.05). Compared with the control group, the relative ANGPTL4 protein expression was increased in the hypoxia group and significantly decreased in the hypoxia+ si-ANGPTL4 group, showing statistically significant differences (both P<0.05). The number of tube formations in the control group, hypoxia group, and hypoxia+ si-ANGPTL4 group were 12.67±1.53, 19.64±1.56, and 17.01±1.04, respectively, with a statistically significant overall difference ( F=33.091, P<0.01). The number of tube formations increased in the hypoxia group and hypoxia+ si-ANGPTL4 group compared with the control group, and the number of tube formations decreased in the hypoxia+ si-ANGPTL4 group compared with the hypoxia group, with statistically significant differences (all P<0.05). Relative expression levels of ANGPTL4 and VEGF proteins were significantly lower in the CNV+ si-ANGPTL4 group than those in the CNV group (both P<0.05). The CNV area was significantly lower in the CNV+ si-ANGPTL4 group than in the CNV group and CNV+ si-NC group (both P<0.05). Conclusions:Hypoxia-induced ANGPTL4 promotes experimental CNV formation in vivo and in vitro.Inhibiting ANGPTL4 can reduce CNV formation and leakage.
5.Design and performance verification of high altitude adaptive oxygen generator
Bo WANG ; Xiao-feng LIU ; Wen-jia LIU ; Yi LI ; Ya-nan WU ; Shu-jie CUI ; Wei ZHANG
Chinese Medical Equipment Journal 2025;46(4):29-34
Objective To design a high altitude adaptive oxygen generator for the crews to alleviate their high altitude reaction in high altitude environment and meet their requirements for oxygen supply.Methods A high altitude adaptive oxygen generator based on the mature pressure swing adsorption oxygen production method was designed with the key technologies of discharge capacity compensation of air compression pump and airway fusion of molecular sieve tower,which had the components of molecular sieve tower,air compression pump,controller,cooling fan,cooler,solenoid valve,regulator,flow meter and etc.Trials were carried out at the simulated altitude and field plateau environment so as to verify the high altitude adaptive performance of the oxygen generator developed.Results The trial results showed the oxygen generator met the desired objectives and the requirements for oxygen volume fraction in GJB 2799-1996 General specification for medical oxygen generator using molecular sieve method.Conclusion The oxygen generartor provides oxygen supply effectively for vehicle operators in plateau environments or the ones rushing into the plateau.[Chinese Medical Equipment Journal,2025,46(4):29-34]
6.Study on medical equipment configuration management of ovarian tissue cryopreservation and transplantation
Lu JIA ; Juan DU ; Yu LI ; Huan-shu LIU ; Zhao ZHANG ; Xiao-li LIU ; Xiang-yan RUAN
Chinese Medical Equipment Journal 2025;46(4):63-69
The technologies for ovarian tissue cryopreservation and entire process for ovarian tissue cryopreservation and transplantation were introduced,and the medical equipment configuration was summarized for each stage of ovarian tissue cryopreservation and transplantation.Detailed plans and management methods were proposed for the medical equipment configuration of ovarian tissue cryopreservation and transplantation,and relevant precautions,possible problems and solutions during the process were put forward.References were provided for medical institutions planning to carry out ovarian tissue cryopreservation and transplantation.[Chinese Medical Equipment Journal,2025,46(4):63-69]
7.Promotive effect of hypoxia-induced ANGPTL4 expression on experimental choroidal neovascularization
Jia CHEN ; Ying YANG ; Shu SU ; Shenglai ZHANG ; Xiaowei YANG ; Aimin SANG
Chinese Journal of Experimental Ophthalmology 2025;43(10):906-914
Objective:To investigate the role of hypoxia-induced angiopoietin-like protein 4 (ANGPTL4) expression in experimental choroidal neovascularization (CNV).Methods:Twenty-seven SPF male C57BL/6J mice aged 6-8 weeks were selected.Eighteen of the mice were used to establish a laser-induced CNV model.On the 7th day after laser photocoagulation, success of the modeling was verified using optical coherence tomography angiography (OCTA) and fundus fluorescein angiography (FFA). The retinal pigment epithelium (RPE)-choroid-sclera complex was extracted for protein analysis before modeling and on the 3rd and 7th days after modeling.The relative expression levels of ANGPTL4 and vascular endothelial growth factor (VEGF) at different time points were detected by Western blot.Additionally, frozen sections of mouse eyeballs on day 7 after modeling were prepared and the expression and cellular localization of ANGPTL4 were observed by immunofluorescence.RF/6A cells, derived from monkey choroidal retinal endothelial cells, were treated with 200 μmol/L cobalt chloride (CoCl 2) in the culture medium for 0, 3, 6, and 12 hours.RF/6A cells were also divided into a normal control group, a hypoxia group, and a hypoxia+ si-ANGPTL4 group, and cells were transfected with a plasmid containing si-ANGPTL4 sequence.The relative expression levels of ANGPTL4 and VEGF proteins in each group were detected by Western blot, and the differences in tube formation among the groups were observed by tube formation assay.A total of 27 male C57BL/6J mice were randomly divided into CNV group, CNV+ si-NC group, and CNV+ si-ANGPTL4 group, with 9 mice in each group.In the CNV+ si-NC and CNV+ si-ANGPTL4 groups, si-NC and si-ANGPTL4 were respectively injected into the vitreous cavity after the CNV model was established.Fluorescence leakage in mice was observed by FFA, and the length, thickness and area of CNV was observed using OCTA and immunofluorescence staining of choroidal flat mounts.The relative expression levels of ANGPTL4 and VEGF proteins in each group were detected by Western blot.All animal experiments were conducted in accordance with ARVO Statement on the Use of Animals in Ophthalmic and Vision Research.The experimental protocol was approved by the Affiliated Hospital of Nantong University (No.S20220822-902). Results:Before modeling and on the 3rd and 7th days after modeling, the relative expression levels of ANGPTL4 protein were 1.00±0.00, 1.58±0.05, and 1.90±0.04, respectively, and the relative expression levels of VEGF protein were 1.00±0.00, 1.31±0.05, and 1.84±0.04, respectively, with statistically significant overall differences ( F=528.934, 390.424, both P<0.05). Among them, on the 3rd and 7th days after modeling, the relative expression levels of ANGPTL4 and VEGF proteins were significantly higher in CNV group than in the control group (all P<0.05). The tissues of each layer of the retina were clear in the control group, while neovascularization could be seen growing under the retinal neuroepithelial layer in the CNV group.Compared with the control group, ANGPTL4 expression was significantly increased and colocalized with vascular endothelial cells in the CNV group.After CoCl 2 treatment of RF/6A cells for 3, 6, and 12 hours, the relative expression levels of ANGPTL4 and VEGF proteins were higher than at 0 hour, with statistically significant differences (all P<0.05). Compared with the control group, the relative ANGPTL4 protein expression was increased in the hypoxia group and significantly decreased in the hypoxia+ si-ANGPTL4 group, showing statistically significant differences (both P<0.05). The number of tube formations in the control group, hypoxia group, and hypoxia+ si-ANGPTL4 group were 12.67±1.53, 19.64±1.56, and 17.01±1.04, respectively, with a statistically significant overall difference ( F=33.091, P<0.01). The number of tube formations increased in the hypoxia group and hypoxia+ si-ANGPTL4 group compared with the control group, and the number of tube formations decreased in the hypoxia+ si-ANGPTL4 group compared with the hypoxia group, with statistically significant differences (all P<0.05). Relative expression levels of ANGPTL4 and VEGF proteins were significantly lower in the CNV+ si-ANGPTL4 group than those in the CNV group (both P<0.05). The CNV area was significantly lower in the CNV+ si-ANGPTL4 group than in the CNV group and CNV+ si-NC group (both P<0.05). Conclusions:Hypoxia-induced ANGPTL4 promotes experimental CNV formation in vivo and in vitro.Inhibiting ANGPTL4 can reduce CNV formation and leakage.
8.Exploring the Construction of Key miRNA mRNA Networks in TS Model Rats Based on Transcriptomics and Potential Traditional Chinese Medicine Intervention
Fan LI ; Yue-chen ZHANG ; Shan ZHOU ; Jing XIE ; Meng-qing WANG ; Qing-jia ZENG ; Xia ZHOU ; Shu-jing ZHANG
Progress in Modern Biomedicine 2025;25(16):2577-2584,2597
Objective:To investigate the miRNA-mRNA regulatory network in a rat model of Tourette syndrome(TS)using transcriptomic technology and to screen key signaling pathways and potential traditional Chinese medicine(TCM)candidates for intervention.Methods:A TS rat model was established using iminodipropionitrile(IDPN).RNA sequencing was performed to identify differentially expressed miRNAs and mRNAs in the brain tissues of TS rats.Bioinformatics analysis was applied to construct interaction networks,and network pharmacology was further employed to screen potential TCM compounds.Results:After 7 days of IDPN modeling,the model group exhibited motor and stereotypical behavioral changes,with behavioral scores greater than 3 points.Hema toxylin-eosin(HE)staining revealed irregular neuronal nuclear morphology,uneven chromatin distribution,nuclear pyknosis,and increased glial cell density.KEGG enrichment analysis identified key pathways:calcium signaling pathway,neuroactive ligand-receptor interaction,p53 signaling pathway,ECM-receptor interaction,and TGF-β signaling pathway.miR-125a-3p,miR-106-3p,and miR-760-3p were identified as pivotal miRNAs.Potential TCM candidates included Ajuga decumbens,Acanthopanax bark,Codonopsis pilosula,Stephania japonica,Os Draconis,Notopterygium root,Siraitia grosvenorii,Zanthoxylum nitidum root,Morinda officinalis,and Corydalis yanhusuo.Conclusion:The miRNAs miR-106-3p,miR-125a-3p,and miR-760-3p may mediate TS pathogenesis by altering critical signaling networks,including the calcium signaling pathway,neuroactive ligand-receptor interaction,and ECM-receptor interaction pathways,leading to neuroimmune inflammation and dopaminergic system dysregulation.TCM compounds such as Corydalis yanhusuo and Ajuga decumbens may exert therapeutic effects through multi-component synergistic regulation of these miRNAs and downstream pathways.
9.Treating Type 2 Diabetic Nephropathy by Down-regulating NOX4 to Inhibit the Oxidative Stress Pathway in Mesenchymal Stem Cells
Shu-Qi FENG ; Guo-Rong JIN ; Qun-Hang XUE ; Min HE ; Ze-Hang WANG ; Jia-Xin YAO ; Long CHEN ; Yu-Jiao WANG ; An-Xiu ZHANG ; Sheng HE ; Bing-Rui ZHOU ; Jun XIE
Chinese Journal of Biochemistry and Molecular Biology 2025;41(5):730-740
Diabetic nephropathy(DN)is a serious complication of diabetes mellitus and a leading cause of end-stage renal diseases.In DN patients,key pathological mechanisms include proteinuria,glomerulo-sclerosis,and fibrosis,largely driven by poor glycemic control and oxidative stress caused by prolonged hyperglycemia.This stress damages renal podocytes and triggers inflammatory mesenchymal infiltration of renal tubular cells,exacerbating the progression of proteinuria and fibrosis.Human umbilical cord-de-rived mesenchymal stem cells(hUC-MSCs)offer promising potential for treating DN due to their strong anti-oxidative properties.In this study,we developed a DN mouse model and treated the mouse via tail vein injections of hUC-MSCs(1×106 cells/mouse).The results indicated that hUC-MSCs significantly lowered fasting blood glucose levels(22.5±3.0 vs 14.7±1.1,P<0.01)and improved glucose toler-ance,as shown by intraperitoneal glucose tolerance test(IPGTT)results(P<0.05).Additionally,the renal function improved in hUC-MSCs-treated mice,with marked reductions in oxidative stress markers,including blood urea nitrogen(BUN),urinary creatinine(Ucr),urinary protein(PRO),superoxide dismutase(SOD),and malondialdehyde(MDA)(P<0.05).Histological analyses through hematoxy-lin-eosin(H&E),Periodic Acid-Schiff(PAS),and Sirius red staining demonstrated alleviation of glo-merular mesangial hyperplasia,glomerular hypertrophy,and tubular inflammation.Furthermore,hUC-MSCs treatment downregulated the expression of oxidative stress-related proteins,such as NADPH oxi-dase 4(NOX4)and thioredoxin-interacting protein(TXNIP),and reduced reactive oxygen species(ROS)production(P<0.05).Meanwhile,human renal cortical proximal tubule epithelial cells(HK-2 cells)were selected for validation in vitro experiments using high glucose treatment followed by super-natants of hUC-MSCs(MSC-CM),and Western blotting showed that the expression of both NOX4 and TXNIP was inhibited(P<0.05)and ROS expression was reduced.In conclusion,hUC-MSC treatment effectively lowered blood glucose levels and improved renal function in DN mice,likely through the sup-pression of NOX4 expression and TXNIP-mediated oxidative stress.
10.Structure and Function of GPR126/ADGRG6
Ting-Ting WU ; Si-Qi JIA ; Shu-Zhu CAO ; De-Xin ZHU ; Guo-Chao TANG ; Zhi-Hua SUN ; Xing-Mei DENG ; Hui ZHANG
Progress in Biochemistry and Biophysics 2025;52(2):299-309
GPR126, also known as ADGRG6, is one of the most deeply studied aGPCRs. Initially, GPR126 was thought to be a receptor associated with muscle development and was primarily expressed in the muscular and skeletal systems. With the deepening of research, it was found that GPR126 is expressed in multiple mammalian tissues and organs, and is involved in many biological processes such as embryonic development, nervous system development, and extracellular matrix interactions. Compared with other aGPCRs proteins, GPR126 has a longer N-terminal domain, which can bind to ligands one-to-one and one-to-many. Its N-terminus contains five domains, a CUB (complement C1r/C1s, Uegf, Bmp1) domain, a PTX (Pentraxin) domain, a SEA (Sperm protein, Enterokinase, and Agrin) domain, a hormone binding (HormR) domain, and a conserved GAIN domain. The GAIN domain has a self-shearing function, which is essential for the maturation, stability, transport and function of aGPCRs. Different SEA domains constitute different GPR126 isomers, which can regulate the activation and closure of downstream signaling pathways through conformational changes. GPR126 has a typical aGPCRs seven-transmembrane helical structure, which can be coupled to Gs and Gi, causing cAMP to up- or down-regulation, mediating transmembrane signaling and participating in the regulation of cell proliferation, differentiation and migration. GPR126 is activated in a tethered-stalk peptide agonism or orthosteric agonism, which is mainly manifested by self-proteolysis or conformational changes in the GAIN domain, which mediates the rapid activation or closure of downstream pathways by tethered agonists. In addition to the tethered short stem peptide activation mode, GPR126 also has another allosteric agonism or tunable agonism mode, which is specifically expressed as the GAIN domain does not have self-shearing function in the physiological state, NTF and CTF always maintain the binding state, and the NTF binds to the ligand to cause conformational changes of the receptor, which somehow transmits signals to the GAIN domain in a spatial structure. The GAIN domain can cause the 7TM domain to produce an activated or inhibited signal for signal transduction, For example, type IV collagen interacts with the CUB and PTX domains of GPR126 to activate GPR126 downstream signal transduction. GPR126 has homology of 51.6%-86.9% among different species, with 10 conserved regions between different species, which can be traced back to the oldest metazoans as well as unicellular animals.In terms of diseases, GPR126 dysfunction involves the pathological process of bone, myelin, embryo and other related diseases, and is also closely related to the occurrence and development of malignant tumors such as breast cancer and colon cancer. However, the biological function of GPR126 in various diseases and its potential as a therapeutic target still needs further research. This paper focuses on the structure, interspecies differences and conservatism, signal transduction and biological functions of GPR126, which provides ideas and references for future research on GPR126.

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