1.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.
2.In situ Analytical Techniques for Membrane Protein Interactions
Zi-Yuan KANG ; Tong YU ; Chao LI ; Xue-Hua ZHANG ; Jun-Hui GUO ; Qi-Chang LI ; Jing-Xing GUO ; Hao XIE
Progress in Biochemistry and Biophysics 2025;52(5):1206-1218
Membrane proteins are integral components of cellular membranes, accounting for approximately 30% of the mammalian proteome and serving as targets for 60% of FDA-approved drugs. They are critical to both physiological functions and disease mechanisms. Their functional protein-protein interactions form the basis for many physiological processes, such as signal transduction, material transport, and cell communication. Membrane protein interactions are characterized by membrane environment dependence, spatial asymmetry, weak interaction strength, high dynamics, and a variety of interaction sites. Therefore, in situ analysis is essential for revealing the structural basis and kinetics of these proteins. This paper introduces currently available in situ analytical techniques for studying membrane protein interactions and evaluates the characteristics of each. These techniques are divided into two categories: label-based techniques (e.g., co-immunoprecipitation, proximity ligation assay, bimolecular fluorescence complementation, resonance energy transfer, and proximity labeling) and label-free techniques (e.g., cryo-electron tomography, in situ cross-linking mass spectrometry, Raman spectroscopy, electron paramagnetic resonance, nuclear magnetic resonance, and structure prediction tools). Each technique is critically assessed in terms of its historical development, strengths, and limitations. Based on the authors’ relevant research, the paper further discusses the key issues and trends in the application of these techniques, providing valuable references for the field of membrane protein research. Label-based techniques rely on molecular tags or antibodies to detect proximity or interactions, offering high specificity and adaptability for dynamic studies. For instance, proximity ligation assay combines the specificity of antibodies with the sensitivity of PCR amplification, while proximity labeling enables spatial mapping of interactomes. Conversely, label-free techniques, such as cryo-electron tomography, provide near-native structural insights, and Raman spectroscopy directly probes molecular interactions without perturbing the membrane environment. Despite advancements, these methods face several universal challenges: (1) indirect detection, relying on proximity or tagged proxies rather than direct interaction measurement; (2) limited capacity for continuous dynamic monitoring in live cells; and (3) potential artificial influences introduced by labeling or sample preparation, which may alter native conformations. Emerging trends emphasize the multimodal integration of complementary techniques to overcome individual limitations. For example, combining in situ cross-linking mass spectrometry with proximity labeling enhances both spatial resolution and interaction coverage, enabling high-throughput subcellular interactome mapping. Similarly, coupling fluorescence resonance energy transfer with nuclear magnetic resonance and artificial intelligence (AI) simulations integrates dynamic structural data, atomic-level details, and predictive modeling for holistic insights. Advances in AI, exemplified by AlphaFold’s ability to predict interaction interfaces, further augment experimental data, accelerating structure-function analyses. Future developments in cryo-electron microscopy, super-resolution imaging, and machine learning are poised to refine spatiotemporal resolution and scalability. In conclusion, in situ analysis of membrane protein interactions remains indispensable for deciphering their roles in health and disease. While current technologies have significantly advanced our understanding, persistent gaps highlight the need for innovative, integrative approaches. By synergizing experimental and computational tools, researchers can achieve multiscale, real-time, and perturbation-free analyses, ultimately unraveling the dynamic complexity of membrane protein networks and driving therapeutic discovery.
3.Aberrant fragmentomic features of circulating cell-free mitochondrial DNA enable early detection and prognosis prediction of hepatocellular carcinoma
Yang LIU ; Fan PENG ; Siyuan WANG ; Huanmin JIAO ; Kaixiang ZHOU ; Wenjie GUO ; Shanshan GUO ; Miao DANG ; Huanqin ZHANG ; Weizheng ZHOU ; Xu GUO ; Jinliang XING
Clinical and Molecular Hepatology 2025;31(1):196-212
Background/Aims:
Early detection and effective prognosis prediction in patients with hepatocellular carcinoma (HCC) provide an avenue for survival improvement, yet more effective approaches are greatly needed. We sought to develop the detection and prognosis models with ultra-sensitivity and low cost based on fragmentomic features of circulating cell free mtDNA (ccf-mtDNA).
Methods:
Capture-based mtDNA sequencing was carried out in plasma cell-free DNA samples from 1168 participants, including 571 patients with HCC, 301 patients with chronic hepatitis B or liver cirrhosis (CHB/LC) and 296 healthy controls (HC).
Results:
The systematic analysis revealed significantly aberrant fragmentomic features of ccf-mtDNA in HCC group when compared with CHB/LC and HC groups. Moreover, we constructed a random forest algorithm-based HCC detection model by utilizing ccf-mtDNA fragmentomic features. Both internal and two external validation cohorts demonstrated the excellent capacity of our model in distinguishing early HCC patients from HC and highrisk population with CHB/LC, with AUC exceeding 0.983 and 0.981, sensitivity over 89.6% and 89.61%, and specificity over 98.20% and 95.00%, respectively, greatly surpassing the performance of alpha-fetoprotein (AFP) and mtDNA copy number. We also developed an HCC prognosis prediction model by LASSO-Cox regression to select 20 fragmentomic features, which exhibited exceptional ability in predicting 1-year, 2-year and 3-year survival (AUC=0.8333, 0.8145 and 0.7958 for validation cohort, respectively).
Conclusions
We have developed and validated a high-performing and low-cost approach in a large clinical cohort based on aberrant ccf-mtDNA fragmentomic features with promising clinical translational application for the early detection and prognosis prediction of HCC patients.
4.Aberrant fragmentomic features of circulating cell-free mitochondrial DNA enable early detection and prognosis prediction of hepatocellular carcinoma
Yang LIU ; Fan PENG ; Siyuan WANG ; Huanmin JIAO ; Kaixiang ZHOU ; Wenjie GUO ; Shanshan GUO ; Miao DANG ; Huanqin ZHANG ; Weizheng ZHOU ; Xu GUO ; Jinliang XING
Clinical and Molecular Hepatology 2025;31(1):196-212
Background/Aims:
Early detection and effective prognosis prediction in patients with hepatocellular carcinoma (HCC) provide an avenue for survival improvement, yet more effective approaches are greatly needed. We sought to develop the detection and prognosis models with ultra-sensitivity and low cost based on fragmentomic features of circulating cell free mtDNA (ccf-mtDNA).
Methods:
Capture-based mtDNA sequencing was carried out in plasma cell-free DNA samples from 1168 participants, including 571 patients with HCC, 301 patients with chronic hepatitis B or liver cirrhosis (CHB/LC) and 296 healthy controls (HC).
Results:
The systematic analysis revealed significantly aberrant fragmentomic features of ccf-mtDNA in HCC group when compared with CHB/LC and HC groups. Moreover, we constructed a random forest algorithm-based HCC detection model by utilizing ccf-mtDNA fragmentomic features. Both internal and two external validation cohorts demonstrated the excellent capacity of our model in distinguishing early HCC patients from HC and highrisk population with CHB/LC, with AUC exceeding 0.983 and 0.981, sensitivity over 89.6% and 89.61%, and specificity over 98.20% and 95.00%, respectively, greatly surpassing the performance of alpha-fetoprotein (AFP) and mtDNA copy number. We also developed an HCC prognosis prediction model by LASSO-Cox regression to select 20 fragmentomic features, which exhibited exceptional ability in predicting 1-year, 2-year and 3-year survival (AUC=0.8333, 0.8145 and 0.7958 for validation cohort, respectively).
Conclusions
We have developed and validated a high-performing and low-cost approach in a large clinical cohort based on aberrant ccf-mtDNA fragmentomic features with promising clinical translational application for the early detection and prognosis prediction of HCC patients.
5.Aberrant fragmentomic features of circulating cell-free mitochondrial DNA enable early detection and prognosis prediction of hepatocellular carcinoma
Yang LIU ; Fan PENG ; Siyuan WANG ; Huanmin JIAO ; Kaixiang ZHOU ; Wenjie GUO ; Shanshan GUO ; Miao DANG ; Huanqin ZHANG ; Weizheng ZHOU ; Xu GUO ; Jinliang XING
Clinical and Molecular Hepatology 2025;31(1):196-212
Background/Aims:
Early detection and effective prognosis prediction in patients with hepatocellular carcinoma (HCC) provide an avenue for survival improvement, yet more effective approaches are greatly needed. We sought to develop the detection and prognosis models with ultra-sensitivity and low cost based on fragmentomic features of circulating cell free mtDNA (ccf-mtDNA).
Methods:
Capture-based mtDNA sequencing was carried out in plasma cell-free DNA samples from 1168 participants, including 571 patients with HCC, 301 patients with chronic hepatitis B or liver cirrhosis (CHB/LC) and 296 healthy controls (HC).
Results:
The systematic analysis revealed significantly aberrant fragmentomic features of ccf-mtDNA in HCC group when compared with CHB/LC and HC groups. Moreover, we constructed a random forest algorithm-based HCC detection model by utilizing ccf-mtDNA fragmentomic features. Both internal and two external validation cohorts demonstrated the excellent capacity of our model in distinguishing early HCC patients from HC and highrisk population with CHB/LC, with AUC exceeding 0.983 and 0.981, sensitivity over 89.6% and 89.61%, and specificity over 98.20% and 95.00%, respectively, greatly surpassing the performance of alpha-fetoprotein (AFP) and mtDNA copy number. We also developed an HCC prognosis prediction model by LASSO-Cox regression to select 20 fragmentomic features, which exhibited exceptional ability in predicting 1-year, 2-year and 3-year survival (AUC=0.8333, 0.8145 and 0.7958 for validation cohort, respectively).
Conclusions
We have developed and validated a high-performing and low-cost approach in a large clinical cohort based on aberrant ccf-mtDNA fragmentomic features with promising clinical translational application for the early detection and prognosis prediction of HCC patients.
6.Mechanism of Shugan Huazheng Prescription Against Liver Fibrosis Based on HIF-1α/VEGF/TGF-β1 Pathway
Anli XING ; Kunpeng ZHAO ; Qiuju ZHANG ; Jiena LI ; Shiyu CHEN ; Jiaqi GUO ; Ming ZHANG
Chinese Journal of Experimental Traditional Medical Formulae 2024;30(8):57-65
ObjectiveTo observe the therapeutic effect of Shugan Huazheng prescription on hepatic fibrosis model rats induced by carbon tetrachloride (CCl4) and explore whether it plays its role through hypoxia-induced factor-1α/vascular endothelial growth factor/transforming growth factor-β1 (HIF-1α/VEGF/TGF-β1) pathway. MethodA total of 54 male SPF SD rats were randomly divided into six groups: blank group, model group, colchicine group (0.2 mg·kg-1), and high-, medium-, and low-dose groups (29.52, 14.76, and 7.38 g·kg-1) of Shugan Huazheng prescription, with nine rats in each group. The molding was conducted three times a week for eight weeks. Administration began the day after the first injection, and the drug intervention was once a day for eight weeks. On the day after the last administration, the rats were deprived of food and water, and they were killed the next day, during which the physiological status of each group of rats was dynamically monitored. The pathological changes in the liver were observed by hematoxylin-eosin (HE) staining, and the content of hydroxyproline (HYP) and angiotensin Ⅱ (AngⅡ) in liver tissue were detected by enzyme-related immunosorbent assay (ELISA). Real-time fluorescent quantitative PCR (Real-time PCR) was used to determine the mRNA expression levels of HIF-1α, VEGF, and TGF-β1 in liver tissue, and immunohistochemical method (IHC) and Western blot were used to detect the protein expression levels of HIF-1α, VEGF, and TGF-β1 in liver tissue. ResultCompared with the blank group, the overall condition of rats in the model group decreased significantly. The proliferation of connective tissue and the increase in adipose cells between hepatocytes were obvious. The content of HYP and Ang was increased. The mRNA and protein expressions of HIF-1α, VEGF, and TGF-β1 were increased to varying degrees (P<0.05). Compared with the model group, the proliferation of connective tissue and inflammatory cell infiltration in the liver tissue of colchicine and Shugan Huazheng prescription groups were reduced. The content of HYP and Ang was decreased. The mRNA and protein expression levels of HIF-1α, VEGF, and TGF-β1 were decreased, and the colchicine group and high-dose group of Shugan Huazheng prescription were the most significant (P<0.05). ConclusionShugan Huazheng prescription has an obvious therapeutic effect on CCl4-induced hepatic fibrosis model rats. Its therapeutic mechanism may be related to the regulation of the HIF-1α/VEGF/TGF-β1 signaling pathway and the improvement of hepatic hypoxia, vascular remodeling, and the syndrome of Qi deficiency and blood stasis in hepatic fibrosis.
7. A new strategy for evaluating antitumor activity in vitro with time-dimensional characteristics of RTCA technology
Fang-Tong LIU ; Shu-Yan XING ; Jia YANG ; Guo-Ying ZHANG ; Rong RONG ; Xiao-Yun LIU ; Dong-Xue YE ; Yong YANG ; Xiao-Yun LIU ; Dong-Xue YE ; Rong RONG ; Yong YANG ; Xiao-Yun LIU ; Dong-Xue YE ; Yong YANG ; Xiao-Yun LIU ; Dong-Xue YE ; Yong YANG
Chinese Pharmacological Bulletin 2024;40(3):592-598
Aim To analyze the anti-A549 and HI299 lung ade-nocarcinoma activities via using examples of baicalin, astragalo-side, hesperidin and cisplatin based on real time cellular analysis (RTCA) technology, and to build a new strategy for EC50 e-valuation reflecting the time-dimensional characteristic. Methods Using RTCA Software Pro for data analysis and GraphPad Prism and Origin Pro plotting, the in vitro anti-A549 and H1299 lung adenocarcinoma activities of baicalin, astragaloside, hesperidin, and cisplatin were characterized using the endpoint method and time dimension, respectively. Results (X) There were significant differences in EC50 values of A549 and H1299 cells at 24 h and 48 h endpoint methods. (2) The correlation coefficient of the curve fitted with the four-parameter equation was > 0. 9, and the dynamic change of EC50 remained relatively stable (the linear fitting of EC50 at adjacent 4 points I slope 1^1) used to calculate the EC50 value within this time dimension. The EC50 of baicalin, astragaloside, hesperidin and cisplatin on A549 cells was 52. 97 ±1.75 плпо! • L~1(16~48 h) , 62.88 ± 2.91 ijunol • L"1 (32.25 -48 h) , 78.84 ±0.33 плпо1 • L"1 (21.5 -29.75 h), 13.57 ±1.54 плпо1 • L_1(27.5 -48 h), respectively; the EC50 of baicalin, astragaloside, hesperidin and cisplatin on H1299 cells was 43. 71 ± 1. 26 |лто1 • L_1 ( 19. 5 -48 h), 47.23 ±1. 19 |лто1 • L_1(14 -48 h) , 39.45 ±0.24 плпо1 • L"1 (12.75 -46.25 h), 25.97 ±4.76 плпо1 • L"1 (10. 25 -48 h) , respectively. The results showed that the time window for the anti-tumor effect of the test solution/drug was different. Conclusions Based on RTCA technology, it is more accurate and reasonable to select EC50 data that exhibit better fitting, stable changes, and time-dimensional characteristics for the evaluation of anti-tumor activity. In addition, this method of distinguishing different effective time of antitumor drugs can provide a reference for the timing of clinical combination drugs, and this approach will also provide a reference for further related studies.
8.Effects of 5G mobile phone radiofrequency radiation exposure on male mouse fertility
Zhaowen ZHANG ; Guiqiang ZHOU ; Ling GUO ; Tongzhou QIN ; Xing WANG ; Guirong DING
Chinese Journal of Radiological Health 2024;33(2):135-141
Objective To clarify the effects of 5G mobile phone radiofrequency radiation exposure on male mouse fertility and to preliminarily explore the underlying mechanisms. Methods Healthy male C57BL/6 mice aged 7-8 weeks were randomly assigned to Sham group, 3.5 GHz radiofrequency radiation group, and 4.9 GHz radiofrequency radiation group, with 16 mice in each group. The mice were exposed to 3.5 GHz or 4.9 GHz mobile phone radiofrequency radiation for 42 consecutive days (1 h per day). The sperm quality was evaluated using sperm count, deformity rate, and motility. H&E staining was performed to assess testicular tissue structure by observing the morphology of spermatogenic cells at various development stages, the diameter of seminiferous tubules, and the thickness of seminiferous epithelium. The sperm mitochondrial function was assessed using sperm mitochondrial membrane potential and testicular ATP content. The fertility of mice was evaluated through fertility rate, litter size, and survival rate of offspring. The underlying mechanisms were explored by detecting the methylation of LRGUK gene and its mRNA and protein levels. Results Compared with the Sham group, there were no significant changes in sperm count in the 3.5 GHz and 4.9 GHz groups; however, the sperm abnormality rate significantly increased (P < 0.05) and sperm motility significantly decreased (P < 0.05). The structure of testicular tissue, the function of sperm mitochondria, and fertility of mice showed no significant changes as compared with the Sham group. The methylation level of LRGUK gene in the testes significantly increased, while the mRNA and protein expression levels significantly decreased. Conclusion Exposure to 3.5 GHz and 4.9 GHz mobile phone radiofrequency radiation for 42 consecutive days can lead to an increase in sperm deformity rate and a decrease in sperm motility in mice, but has no significant effect on fertility, which may be related to an increase in methylation level of the LRGUK gene in the testes.
9.The Regulatory Function of ADAR1-mediated RNA Editing in Hematological Malignancies
Xing-Yu WAN ; Huan-Ping GUO ; Rui-Hao HUANG ; Xiao-Qi WANG ; Ling-Yu ZENG ; Tao WU ; Lin XIA ; Xi ZHANG
Progress in Biochemistry and Biophysics 2024;51(2):300-308
RNA editing, an essential post-transcriptional reaction occurring in double-stranded RNA (dsRNA), generates informational diversity in the transcriptome and proteome. In mammals, the main type of RNA editing is the conversion of adenosine to inosine (A-to-I), processed by adenosine deaminases acting on the RNAs (ADARs) family, and interpreted as guanosine during nucleotide base-pairing. It has been reported that millions of nucleotide sites in human transcriptome undergo A-to-I editing events, catalyzed by the primarily responsible enzyme, ADAR1. In hematological malignancies including myeloid/lymphocytic leukemia and multiple myeloma, dysregulation of ADAR1 directly impacts the A-to-I editing states occurring in coding regions, non-coding regions, and immature miRNA precursors. Subsequently, aberrant A-to-I editing states result in altered molecular events, such as protein-coding sequence changes, intron retention, alternative splicing, and miRNA biogenesis inhibition. As a vital factor of the generation and stemness maintenance in leukemia stem cells (LSCs), disordered RNA editing drives the chaos of molecular regulatory network and ultimately promotes the cell proliferation, apoptosis inhibition and drug resistance. At present, novel drugs designed to target RNA editing(e.g., rebecsinib) are under development and have achieved outstanding results in animal experiments. Compared with traditional antitumor drugs, epigenetic antitumor drugs are expected to overcome the shackle of drug resistance and recurrence in hematological malignancies, and provide new treatment options for patients. This review summarized the recent advances in the regulation mechanism of ADAR1-mediated RNA editing events in hematologic malignancies, and further discussed the medical potential and clinical application of ADAR1.
10.Analysis of the current situation, advantages and difficulties of standardized management of Investigator Initiated Clinical Trials
Yingshuo HUANG ; Xu ZUO ; Yue LI ; Lihan XING ; Shuilong GUO ; Zhenchang WANG ; Shutian ZHANG
Chinese Journal of Medical Science Research Management 2024;37(1):70-74
Objective:To assess the current situation, advantages, and difficulties of standardized management in Investigator-Initiated Clinical Trials (IIT).Methods:This article summarized the requirements and policies for clinical research management, the development of clinical research domestically and internationally, the achievements and advantages of clinical research management development in China, and the main problems and difficulties with the standardized IIT management in China, and compiled the experiences and models of several medical institutions in IIT management.Results:While China has a large number of clinical medical publications and is ranked high in the world, the quality of the publications needs to be further improved. Domestic management requirements for IIT were gradually improving, providing a basis for medical institutions to implement standardized management throughout the lifecycle of IIT, and achieve certain progress. However, there were still challenges in the departmental divisions, the unification of management standards, whole-process management and quality control, the scientific review, high-risk project management, and registration.Conclusions:Drawing on the excellent experience of domestic medical institutions, measures including identifying a primary responsible department, establishing unified supervision and inspection standards, and implementing a whole life cycle management may help overcome the challenges in IIT management and improve the quality and efficiency of IIT management.

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