1.cGAS: Its Canonical and Non-canonical Functions
Wen-Xian ZHENG ; Meng-Jie XIONG ; Shu-Ting JIA ; Ruo-Yu ZHOU
Progress in Biochemistry and Biophysics 2026;53(5):1279-1296
Cyclic GMP-AMP synthase (cGAS), a pivotal molecule in innate immunity, has emerged as a keypoint in interdisciplinary research at the intersection of basic immunology and tumor biology. As a cytosolic nucleic acid sensor, cGAS is primarily characterized by its capacity to recognize double-stranded DNA (dsDNA) in the cytosol. Upon binding to dsDNA, cGAS undergoes a conformational change that promotes its dimerization and subsequent enzymatic activation. Once activated, it catalyzes the synthesis of the second messenger 2',3'-cGAMP from ATP and GTP. cGAMP then binds to the adaptor protein STING, which resides on the endoplasmic reticulum (ER) membrane. The binding process triggers STING to traffic from the ER to the Golgi apparatus, where it is phosphorylated by the kinase TBK1. Phosphorylated STING serves as a docking site for the transcription factor IRF3, facilitating its phosphorylation by TBK1. Once phosphorylated, IRF3 forms dimers and translocates to the nucleus, where it drives the expression of type I interferons and pro-inflammatory cytokines, initiating a potent antimicrobial state. The DNA-sensing mechanism of cGAS is inherently non-selective regarding the origin of its ligand. It readily detects exogenous DNA from invading pathogens, thereby playing an indispensable role in host defense against microbial infections. However, this same mechanism also enables cGAS to recognize self-DNA that leaks from the nucleus or mitochondria into the cytosol under various cellular stress conditions. While critical for immunity, the recognition of self-dsDNA by cGAS can disrupt cellular homeostasis and trigger aberrant inflammatory responses. The loss of self-tolerance can precipitate or exacerbate the pathogenesis of autoimmune disorders such as systemic lupus erythematosus (SLE) and Aicardi-Goutières syndrome (AGS), highlighting the dual role of cGAS as both a sentinel for infection and a potential driver of autoimmune pathology. Notably, the subcellular localization of cGAS is not still. Increasing recent researches have revealed that cGAS is also abundant within the nucleus, challenging the traditional view of it solely as a cytosolic nucleic acid sensor. Within the nucleus, cGAS exhibits non-canonical functions that are distinct from its canonical immunological role. First, cGAS exists in a state of stringent immunological silence in the nucleus, with mechanisms involving its competitive binding to histones and its post-translational modifications which block the activation of cGAS enzymatic activity, thus, effectively preventing it from mounting an autoimmune attack on genomic DNA. Second, cGAS plays a critical role in maintaining genomic stability. Upon DNA damage, cGAS is rapidly recruited to the lesion site and participates in the DNA damage repair process. Moreover, under conditions of DNA replication stress, cGAS contributes to the stabilization of replication forks, preventing the cell from entering a state of uncontrolled hyper-replication. Consequently, in light of the dual role of cGAS in both immune regulation and tumor development, the development of small-molecule drugs targeting cGAS holds significant therapeutic promise. This review summarizes the structural characteristics of cGAS and its canonical function as a pattern recognition receptor in the cytosol, including the types of pathogens it recognizes and the autoimmune responses resulting from erroneous recognition of self-DNA. It then focuses on its emerging non-canonical functions within the nucleus, detailing its nucleocytoplasmic shuttling, the mechanisms underlying its nuclear immune quiescence, and its role in mediating DNA damage repair and replication fork stabilization. Finally, the review discusses the progress and application prospects of small-molecule drugs targeting cGAS for the treatment of autoimmune diseases and cancer.
2.cGAS: Its Canonical and Non-canonical Functions
Wen-Xian ZHENG ; Meng-Jie XIONG ; Shu-Ting JIA ; Ruo-Yu ZHOU
Progress in Biochemistry and Biophysics 2026;53(5):1279-1296
Cyclic GMP-AMP synthase (cGAS), a pivotal molecule in innate immunity, has emerged as a keypoint in interdisciplinary research at the intersection of basic immunology and tumor biology. As a cytosolic nucleic acid sensor, cGAS is primarily characterized by its capacity to recognize double-stranded DNA (dsDNA) in the cytosol. Upon binding to dsDNA, cGAS undergoes a conformational change that promotes its dimerization and subsequent enzymatic activation. Once activated, it catalyzes the synthesis of the second messenger 2',3'-cGAMP from ATP and GTP. cGAMP then binds to the adaptor protein STING, which resides on the endoplasmic reticulum (ER) membrane. The binding process triggers STING to traffic from the ER to the Golgi apparatus, where it is phosphorylated by the kinase TBK1. Phosphorylated STING serves as a docking site for the transcription factor IRF3, facilitating its phosphorylation by TBK1. Once phosphorylated, IRF3 forms dimers and translocates to the nucleus, where it drives the expression of type I interferons and pro-inflammatory cytokines, initiating a potent antimicrobial state. The DNA-sensing mechanism of cGAS is inherently non-selective regarding the origin of its ligand. It readily detects exogenous DNA from invading pathogens, thereby playing an indispensable role in host defense against microbial infections. However, this same mechanism also enables cGAS to recognize self-DNA that leaks from the nucleus or mitochondria into the cytosol under various cellular stress conditions. While critical for immunity, the recognition of self-dsDNA by cGAS can disrupt cellular homeostasis and trigger aberrant inflammatory responses. The loss of self-tolerance can precipitate or exacerbate the pathogenesis of autoimmune disorders such as systemic lupus erythematosus (SLE) and Aicardi-Goutières syndrome (AGS), highlighting the dual role of cGAS as both a sentinel for infection and a potential driver of autoimmune pathology. Notably, the subcellular localization of cGAS is not still. Increasing recent researches have revealed that cGAS is also abundant within the nucleus, challenging the traditional view of it solely as a cytosolic nucleic acid sensor. Within the nucleus, cGAS exhibits non-canonical functions that are distinct from its canonical immunological role. First, cGAS exists in a state of stringent immunological silence in the nucleus, with mechanisms involving its competitive binding to histones and its post-translational modifications which block the activation of cGAS enzymatic activity, thus, effectively preventing it from mounting an autoimmune attack on genomic DNA. Second, cGAS plays a critical role in maintaining genomic stability. Upon DNA damage, cGAS is rapidly recruited to the lesion site and participates in the DNA damage repair process. Moreover, under conditions of DNA replication stress, cGAS contributes to the stabilization of replication forks, preventing the cell from entering a state of uncontrolled hyper-replication. Consequently, in light of the dual role of cGAS in both immune regulation and tumor development, the development of small-molecule drugs targeting cGAS holds significant therapeutic promise. This review summarizes the structural characteristics of cGAS and its canonical function as a pattern recognition receptor in the cytosol, including the types of pathogens it recognizes and the autoimmune responses resulting from erroneous recognition of self-DNA. It then focuses on its emerging non-canonical functions within the nucleus, detailing its nucleocytoplasmic shuttling, the mechanisms underlying its nuclear immune quiescence, and its role in mediating DNA damage repair and replication fork stabilization. Finally, the review discusses the progress and application prospects of small-molecule drugs targeting cGAS for the treatment of autoimmune diseases and cancer.
3.Ultrasound-based radiogenomics: status, applications, and future direction
Si-Rui WANG ; Yu-Ting SHEN ; Bin HUANG ; Hui-Xiong XU
Ultrasonography 2025;44(2):95-111
Radiogenomics, an extension of radiomics, explores the relationship between imaging features and underlying gene expression patterns. This field is instrumental in providing reliable imaging surrogates, thus potentially representing an alternative to genetic testing. The rapidly growing area of radiogenomics that utilizes ultrasound (US) imaging seeks to elucidate the connections between US image characteristics and genomic data. In this review, the authors outline the radiogenomics workflow and summarize the applications of US-based radiogenomics. These include the prediction of gene variations, molecular subtypes, and other biological characteristics, as well as the exploration of the relationships between US phenotypes and cancer gene profiles. Although the field faces various challenges, US-based radiogenomics offers promising prospects and avenues for future research.
4.Study on the inhibitory effect and mechanism of Modified qifang weitong granules on gastric cancer
Xinyuan CHEN ; Chengting WU ; Changzhou XIONG ; Ting WANG ; Yinhang CUI ; Peibin WU ; Wenlong CHEN ; Huilin CHEN ; Caizhi LIN ; Meiwen TANG
China Pharmacy 2025;36(21):2656-2661
OBJECTIVE To investigate the inhibitory effect and mechanism of Modified qifang weitong granules on gastric cancer based on in vitro and in vivo experiments. METHODS Human gastric cancer HGC-27 cells were divided into the following groups: control group (treated with fetal bovine serum), 10% drug-containing serum group, 15% drug-containing serum group, 20% drug-containing serum group, and 5-fluorouracil (5-Fu) group (positive control, 3.90 μg/mL). After culturing the cells in each group with the corresponding serum/drug solution, their proliferation, migratory and invasive abilities, as well as the cell cycle, were assessed. Additionally, the expression levels of epithelial-mesenchymal transition (EMT)-related proteins [E-cadherin, N-cadherin, and vimentin] in the cells were measured. Logarithmic-phase HGC-27 cells were harvested and subcutaneously injected into the right axillary region of nude mice to establish a subcutaneous xenograft tumor model in nude mice. The successfully modeled tumor-bearing nude mice were randomly divided into model group, low-, medium- and high-dose groups of Modified qifang weitong granules (17.65, 35.29 and 70.58 g/kg, respectively), and 5-Fu group (25 mg/kg), with 5 mice in each group. After 14 days of treatment with the corresponding drugs in each group, the histopathological morphology of the tumor tissues in the nude mice was observed. Immunohistochemistry and Western blot assay were employed to detect the expression levels of EMT- related proteins in the tumor tissues of the nude mice. RESULTS In the cell experiment, compared with the control group, the cell proliferation rate, migration rate, number of invasive cells, as well as the expression levels of N-cadherin and vimentin proteins, and the percentage of cells in the G2/M phase were all significantly decreased/reduced in the 15% drug-containing serum group, 20% drug-containing serum group (P<0.05). Conversely, the percentage of cells in the G0/G1 phase and the expression level of E- cadherin protein were significantly increased (P<0.05). In animal experiment, compared with the model group, the high-dose group of Modified qifang weitong granules exhibited significantly reduced tumor mass and expression levels of N-cadherin and vimentin proteins in the tumor tissues of nude mice (P<0.05), while the expression level of E-cadherinprotein in the tumor tissues was significantly increased (P<0.05). Additionally, the tumor cells varied in size and showed extensive necrosis. CONCLUSIONS Modified qifang weitong granules effectively inhibit gastric cancer in both in vitro and in vivo models, and the mechanism of action is related to the suppression of EMT.
5.Research Progress of Autonomic Nerve Regulation in the Treatment of Myocardial Infarction.
Shan-Shan LI ; Meng-Ting XIONG ; Miao-Miao GUO
Acta Academiae Medicinae Sinicae 2025;47(2):309-313
The autonomic nervous system imbalance caused by the overactivation of the sympathetic nerve and the weakened activity of the parasympathetic nerve is closely related to the occurrence and development of myocardial infarction.Autonomic nerve regulation is a new therapeutic approach aiming at inhibiting sympathetic activity and increasing parasympathetic activity.It encompasses magnetic nerve stimulation,optogenetic neuromodulation,and microinjection of botulinum toxin,which could promote the rebalance of the autonomic nervous system,thereby curbing the deterioration of the cardiac function and reducing the occurrence of ventricular arrhythmias after myocardial infarction.This paper reviews the anatomical basis,mechanisms of action,and research advances in intervention strategies of the autonomic nervous system in myocardial infarction.
Humans
;
Myocardial Infarction/physiopathology*
;
Autonomic Nervous System/physiopathology*
;
Autonomic Pathways
6.Isolation,identification,and biological characterization of enterotoxigenic Escherichia coli from a South China tiger
Jing-ru XU ; Zhi-hao ZHU ; Yu-qi LI ; Si-si FAN ; Ya-li KANG ; Yu-bin ZHUO ; Ling-shan HUANG ; Shu-qi QIU ; XUE-YUXI ; Xiao-ping WU ; Yu-ting LIAO ; Wei-ye LIN ; Xiao-ziyi XIAO ; Xue-jin LI ; Teng-teng CHEN ; Xi-pan LIN ; Kai-xiong LIN ; Ke-wei FAN
Chinese Journal of Zoonoses 2025;41(6):567-573
This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.
7.Study on Reentry Strategy and Results of Blood Donors with Single Reagent Reactivity in Wuhan Area.
Ting-Ting XU ; Qin YU ; Song-Qing KE ; Yan CAI ; Song-Li XIE ; Jing XIONG ; Lei ZHAO
Journal of Experimental Hematology 2025;33(2):530-537
OBJECTIVE:
To study the results, re-donation situation and characteristics of single-reagent reactive blood donors who were put into the reentry strategy in Wuhan area, explore the rationality and effectiveness of the current reentry strategy, and provide data support for the improvement of the reentry process of blood donors.
METHODS:
From January 2020 to December 2023, blood donors who conform the reentry criteria and voluntarily applied for returning to Wuhan Blood Center were tested and the results were analyzed. According to the reentry strategy, serological testing and nucleic acid testing were carried out in parallel, serological testing was performed by ELISA with reagents from two different manufacturers, and the primary reactive samples were tested by double-well retest, and HBV/HCV/HIV nucleic acid detection was performed by RT-PCR with an individual donor test mode. Supplementary HBcAb testing was applied for HBV single reagent reactivity by chemiluminescence method. Supplementary TP-WB testing was applied for returning blood donors with repeated TP single reagent reactivity. If returning blood donors with HIV single reagent reactivity were repeated single reagent reactivity, the samples were sent to local CDC for confirmatory test.
RESULTS:
7 098 blood donors were qualified for reentry, 716 donors voluntarily applied for reentry, 436 donors successfully reentry, 251 donors entered the next round, 29 donors could not reentry. The reentry rates for the past four years were 66.67%(42/63), 54.73%(81/148), 60.71%(136/224) and 62.99%(177/281), respectively. Up to December 31, 2023, 275 donors donated blood again, and the donation rates for past four years were 76.19%(32/42), 72.84%(59/81), 61.76%(84/136) and 56.50%(100/177), respectively. After donating blood, 31 donors were disqualified again by blood screening and subjected to permanent deferral. The results of returning to the team had statistical differences in reentry items, educational level, age, and marriage(P < 0.05).
CONCLUSION
The current reentry strategy adopted by the blood donation and supply institution can effectively retain part of blood donors, reduce the negative emotions of blood donors and increase blood resources.
Humans
;
Blood Donors
;
China
;
Hepatitis B
;
Enzyme-Linked Immunosorbent Assay
;
Hepatitis C
;
Male
8.Silencing DDX17 inhibits proliferation and migration of pulmonary arterial smooth muscle cells in vitro by decreasing mTORC1 activity.
Xiangxiang DENG ; Jia WANG ; Mi XIONG ; Ting WANG ; Yongjian YANG ; De LI ; Xiongshan SUN
Journal of Southern Medical University 2025;45(11):2475-2482
OBJECTIVES:
To investigate the mechanism of DDX17 for regulating proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) during the development of pulmonary hypertension (PH).
METHODS:
In murine PASMCs cultured under normoxic or hypoxic conditions, the effects of transfection with si-Ddx17 and insulin treatment, alone or in combination, on cell proliferation and migration were evaluated using Ki-67 immunofluorescence staining, scratch assay and Transwell assay. Western Blotting was performed to detect the changes in protein expression levels of DDX17, 4EBP1, S6, p-4EBP1, and p-S6. In a mouse model of PH induced by intraperitoneal injection of monocrotaline (MCT), the changes in pulmonary vasculature were examined using HE staining following tail vein injection of AD-Ddx17i.
RESULTS:
The PASMCs in hypoxic culture exhibited significantly enhanced cell proliferation and migration and protein expressions of p-4EBP1 and p-S6, and these changes were obviously reversed by transfection with si-Ddx17. Treatment with insulin significantly attenuated the effect of si-Ddx17 against hypoxic exposure-induced changes in PASMCs. In the mouse model of MCT-induced PH, transfection with AD-Ddx17i obviously alleviated pulmonary vascular stenosis and intimal hyperplasia.
CONCLUSIONS
The expression of DDX17 is elevated in hypoxia-induced PASMCs and PH mice, and silencing DDX17 significantly inhibits PASMC proliferation and migration in vitro and pulmonary vascular remodeling in PH mice by reducing mTORC1 activity.
Animals
;
Cell Proliferation
;
Cell Movement
;
DEAD-box RNA Helicases/metabolism*
;
Myocytes, Smooth Muscle/metabolism*
;
Mice
;
Pulmonary Artery/cytology*
;
Hypertension, Pulmonary/metabolism*
;
Mechanistic Target of Rapamycin Complex 1
;
Cells, Cultured
;
Muscle, Smooth, Vascular/cytology*
9.Identification of a Fusobacterial RNA-binding protein involved in host small RNA-mediated growth inhibition.
Pu-Ting DONG ; Mengdi YANG ; Jie HU ; Lujia CEN ; Peng ZHOU ; Difei XU ; Peng XIONG ; Jiahe LI ; Xuesong HE
International Journal of Oral Science 2025;17(1):48-48
Host-derived small RNAs are emerging as critical regulators in the dynamic interactions between host tissues and the microbiome, with implications for microbial pathogenesis and host defense. Among these, transfer RNA-derived small RNAs (tsRNAs) have garnered attention for their roles in modulating microbial behavior. However, the bacterial factors mediating tsRNA interaction and functionality remain poorly understood. In this study, using RNA affinity pull-down assay in combination with mass spectrometry, we identified a putative membrane-bound protein, annotated as P-type ATPase transporter (PtaT) in Fusobacterium nucleatum (Fn), which binds Fn-targeting tsRNAs in a sequence-specific manner. Through targeted mutagenesis and phenotypic characterization, we showed that in both the Fn type strain and a clinical tumor isolate, deletion of ptaT led to reduced tsRNA intake and enhanced resistance to tsRNA-induced growth inhibition. Global RNA sequencing and label-free Raman spectroscopy revealed the phenotypic differences between Fn wild type and PtaT-deficient mutant, highlighting the functional significance of PtaT in purine and pyrimidine metabolism. Furthermore, AlphaFold 3 prediction provides evidence supporting the specific binding between PtaT and Fn-targeting tsRNA. By uncovering the first RNA-binding protein in Fn implicated in growth modulation through interactions with host-derived small RNAs (sRNAs), our study offers new insights into sRNA-mediated host-pathogen interplay within the context of microbiome-host interactions.
Fusobacterium nucleatum/growth & development*
;
RNA-Binding Proteins/genetics*
;
Bacterial Proteins/genetics*
;
RNA, Bacterial/metabolism*
;
Humans
;
RNA, Transfer/metabolism*

Result Analysis
Print
Save
E-mail