ObjectiveThis paper aims to observe the protective effect of Huamoyan granules on knee osteoarthritis （KOA） and explore whether its protective effect is oriented toward an anti-inflammatory direction by regulation of macrophage polarization， which can effectively inhibit the progression of pathological inflammatory response， reduce the release of inflammatory pain mediators， and downregulate the protein expression level of transient receptor potential vanilloid 1 （TRPV1）， so as to provide experimental evidence for its clinical application and investigate its action mechanism. MethodsAfter adaptive feeding， Sprague-Dawley （SD） rats were randomly divided into six groups： sham group， model group， celecoxib group， and high， medium， and low-dose synovitis granule groups （9.6， 4.8， 2.4 g·kg^-1）. The administration dose of celecoxib capsules was 20 mg·kg^-1. There were 10 rats in the sham group and 12 rats in the model group and each administration group. A KOA animal model was established by means of intra-articular injection of sodium iodoacetate into the knee joint. From the 10^th day of the experiment， each administration group was given intragastric administration at a dose of 10 mL·kg^-1 for 4 weeks. General conditions of rats in each group were assessed daily. The pressure pain threshold （PPT） to mechanical stimulation and joint diameter were recorded. X-ray examination was performed on the right knee joints of rats for imaging analysis. Enzyme linked immunosorbent assay （ELISA） was performed to detect the tumor necrosis factor-α （TNF-α）， serum interleukin-1β （IL-1β）， and other pro-inflammatory cytokines in rat serum samples， as well as the expression levels of neurogenic inflammatory mediators such as nerve growth factor （NGF） and calcitonin gene-related peptide （CGRP）. Histopathological changes in the knee joint synovial tissues were examined by hematoxylineosin （HE） staining. Safranin O-fast green staining was performed to observe and evaluate the degree of knee cartilage lesions. Western blot was employed to quantitatively analyze TRPV1， p38 mitogen-activated protein kinase （p38 MAPK）， and phosphorylated （p）-p38 MAPK in rat knee synovial tissues. Immunofluorescence （IF） was used to measure and assess M1/M2 macrophage polarization. ResultsCompared with those in the sham group， the circumference and joint diameter of the right knee were markedly enlarged in the model group （P<0.01）， while PPTs of rats showed a significant reduction （P<0.01）. The contents of IL-1β， TNF-α， CGRP， and NGF in rats' serum were significantly elevated （P<0.01）， and the synovial Krenn score was increased （P<0.01）. The Mankin score of cartilage tissue was increased （P<0.01）， and the protein expressions of TRPV1 and p-p38 MAPK/p38 MAPK were significantly upregulated （P<0.01）. The experimental intervention significantly reduced the proportion of pro-inflammatory M1 macrophages in the total macrophage population （P<0.01）， and the percentage of M2 macrophages was decreased （P<0.01）. The M1/M2 macrophage ratio was significantly elevated （P<0.01）. Knee joint diameters of all dose groups of Huamoyan granules and the celecoxib group were reduced （P<0.01） compared with those of the model group， and the PPT recovery speeds in the high and medium-dose groups of Huamoyan granules were more obvious （P<0.05）. The contents of IL-1β， CGRP， and NGF in the rats' serum in all administration groups were significantly reduced （P<0.05， P<0.01）， and the content of TNF-α in rats' serum was significantly reduced （P<0.01）. All dose groups of Huamoyan granules demonstrated significant reductions in both synovial Krenn score （P<0.05， P<0.01） and protein expression of TRPV1 and p-p38 MAPK/p38 MAPK in rats' synovial tissues （P<0.01）. The percentage of M1 macrophages in the synovial tissues of the celecoxib group and all dose groups of Huamoyan granules was decreased （P<0.01）. The percentage of M2 macrophages was increased （P<0.05）， and the M1/M2 ratio was decreased （P<0.01）. ConclusionHuamoyan granules can alleviate the inflammatory response of KOA， reduce the release of inflammatory pain mediators， and downregulate TRPV1 protein expression by regulating macrophage polarization. Its mechanism may be related to the TRPV1/p38 MAPK signaling pathway， thereby achieving the effect of improving peripheral pain hypersensitivity in KOA.

Objective To analyze the epidemiological characteristics and disease burden of liver cancer in Guangdong Province in 2020, and to provide a scientific foundation for the development of regionalized prevention and control strategies for liver cancer. Methods According to the cancer registry data of Guangdong Province, the incidence, mortality and age-standardized rate by Chinese standard population in 2020 were calculated to analyze the epidemiological characteristics of liver cancer. The disability adjusted life years (DALYs), year of life loss (YLL), year of lived with disability (YLD), and cause-eliminated life expectancy were used to assess the disease burden of liver cancer. Results In 2020, the crude incidence rate and the age-standardized incidence rate of liver cancer in Guangdong Province were 27.79/100 000 and 20.84/100 000，respectively, and the crude mortality rate and the age-standardized mortality rate of liver cancer were 25.49/100,000 and 17.64/100 000, respectively. The total DALY and DALY rate of liver cancer in Guangdong Province were 515 311 person-years and 513.83/100 000, respectively. After eliminating the causes of death from liver cancer, the life expectancy in Guangdong Province increased from 84.60 years to 84.99 years. All indicators consistently demonstrated that the burden of liver cancer was higher in males than that in females, and the burden of liver cancer was higher in rural areas than that in urban areas. Conclusion Liver cancer in Guangdong Province exhibits a high incidence, mortality and disease burden level in 2020. There are obvious differences of gender, age and region in cancer burden. It is necessary to strengthen liver cancer screening and diagnosis and treatment in men, the elderly and those in rural areas to reduce the burden of liver cancer gradually in Guangdong Province.

ObjectiveThis study aims to investigate the action mechanism by which Xiaozheng Zhitong paste （XZP） alleviates bone cancer pain （BCP） by regulating programmed death protein 1 （PD-1）/programmed death-ligand 1 （PD-L1） pathway-induced osteoclast formation. MethodsThirty female C57BL/6 mice were randomly allocated into the following groups （n=6 per group）： normal control group， model group， low‑dose XZP group （31.5 g·kg^-1）， high‑dose XZP group （63 g·kg^-1）， and PD‑1 inhibitor （Niv） group. A bone cancer pain （BCP） model was established by injecting Lewis lung carcinoma cells. Mice in the normal control and model groups received topical application of a blank paste matrix at the wound site. Mice in the low‑ and high‑dose XZP groups were treated with XZP applied topically twice daily. Mice in the Niv group were topically administered the blank paste matrix and additionally received Niv via tail‑vein injection every two days. All interventions were continued for 21 days. During this period， behavioral tests were performed to assess mechanical， motor， and thermal nociceptive sensitivities. After 21 days， all mice were euthanized， and bone tissue from the operated side was collected for sectioning and preservation. Tartrate‑resistant acid phosphatase （TRAP） staining was used to evaluate osteoclast expression in the lesioned bone tissue. Immunohistochemistry was performed to detect the expression of Runt‑related transcription factor 2 （Runx2） in the lesioned bone tissue. Immunofluorescence was employed to assess the expression of PD‑1 and PD‑L1 in the lesioned bone tissue. ResultsCompared with the normal group， the model group showed significantly decreased limb mechanical withdrawal threshold， spontaneous paw flinching， and thermal withdrawal latency （P<0.01）， increased number of osteoclasts in the lesioned bone tissue （P<0.01）， and reduced expression of Runx2 （P<0.01）. Compared with the model group， the BCP mice in the XZP low-dose group， XZP high-dose group， and Niv group exhibited increased limb mechanical withdrawal threshold， movement scores， and thermal withdrawal latency （P<0.01）. The XZP low-dose group showed no significant changes in osteoclast number or Runx2 expression， while the XZP high-dose group and Niv group demonstrated significantly reduced osteoclast numbers （P<0.01） and significantly increased Runx2 expression （P<0.01）. In the lesioned bone tissue of BCP mice， the XZP low-dose group showed no significant decrease in the percentage of PD-1 expression， but a decrease in the percentage of PD-L1 expression （P<0.05）. In contrast， both the XZP high-dose group and the Niv group exhibited significant reductions in the percentages of PD-1 and PD-L1 expression （P<0.01）. ConclusionXZP alleviates the pain of mice with BCP by blocking the PD-1/PD-L1 pathway to inhibit osteoclastogenesis.

ObjectiveTo investigate the effects and underlying mechanisms of Xiaozheng Zhitong Paste （XZP） on bone cancer pain （BCP）. MethodsThirty female BALB/c mice were randomly divided into five groups： a Sham group， a BCP group， a BCP+low-dose XZP group， a BCP+high-dose XZP group， and a BCP+high-dose XZP + protease-activated receptor 2 （PAR2） agonist GB-110 group. BCP mice model was constructed by injecting Lewis lung carcinoma cells into the femoral cavity of the right leg， which was followed by being treated with XZP for 21 d. After 21 d， the mice were sacrificed. Nissl staining was used to evaluate the survival of spinal cord neurons. Immunofluorescence staining was conducted to localize ionized calcium-binding adapter molecule 1 （Iba1） and neuronal nuclear antigen （NeuN） in spinal cord tissue， thereby assessing microglial activation and neuronal survival. Enzyme-linked immunosorbent assay （ELISA） was employed to measure the levels of interleukin-1β （IL-1β）， tumor necrosis factor-α （TNF-α）， interleukin-6 （IL-6）， transforming growth factor-β （TGF-β）， interleukin-4 （IL-4）， and interleukin-10 （IL-10） in spinal cord tissue. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to detect mRNA expression levels associated with M1/M2 polarization of microglia. Western blot analysis was performed to examine the expression of proteins related to microglial polarization as well as those involved in the PAR2/nuclear factor kappa B （NF-κB）/NOD-like receptor protein 3 （NLRP3） signaling pathway in the spinal cord. ResultsCompared with the Sham group， the spinal cord neurons were damaged， the number of Nissl-positive spinal cord neurons in the spinal cord tissue was significantly reduced （P<0.01）， and the rate of NeuN-positive cells was significantly decreased （P<0.01）. The spinal cord microglia were activated， the inflammatory level of the spinal cord tissue was enhanced， and Iba1 staining was significantly enhanced （P<0.01）. The levels of IL-1β， TNF-α， IL-6， TGF-β， IL-4 and IL-10 were significantly increased （P<0.01）. The mRNA expressions of IL-1β， TNF-α and inducible nitric oxide synthase （iNOS） were significantly increased （P<0.01）， and the expression of PAR2， NLRP3， ASC and NF-κB p65 proteins in the spinal cord tissue of the BCP mice was significantly enhanced （P<0.01）. Compared with the BCP group， high-dose XZP treatment significantly increased the number of Nissl-positive spinal cord neurons in the BCP mice （P<0.01）， significantly enhanced the rate of NeuN-positive cells in the spinal cord tissue， and significantly weakened Iba1 staining （P<0.01）. In addition， the levels of IL-1β， TNF-α， and IL-6 were significantly decreased， while the levels of TGF-β， IL-4， and IL-10 were significantly increased （P<0.05， P<0.01）. The mRNA expression levels of IL-1β， TNF-α， and iNOS were decreased， whereas those of cluster of differentiation 206 （CD206）， arginase-1 （Arg-1）， and YM1/2 were significantly increased （P<0.05， P<0.01）. Low-dose and high-dose XZP treatment significantly decreased the expression of PAR2， NLRP3， ASC， and NF-κB p65 proteins in the spinal cord tissue （P<0.05， P<0.01）. These effects could all be significantly eliminated by the PAR2 agonist GB-110. ConclusionXZP can mitigate BCP in mice， which may be achieved through blocking the activated PAR2/NF-κB/NLRP3 pathway.

ObjectiveThe paper aims to investigate the action mechanism by which the Xiaozheng Zhitong paste （XZP） relieves bone cancer pain （BCP）. MethodsA model of mice with BCP was established by using Lewis tumor cells. The therapeutic effects of XZP， the ferroptosis inhibitor Ferrostatin-1 （Fer-1）， and the nuclear factor erythroid 2-related factor 2 （Nrf2） inhibitor Brusatol （Bru） on BCP were examined. Mice were randomly divided into the Sham operation group， BCP group， BCP+XZP-L group， BCP+XZP-H group， BCP+Fer-1 group， and BCP+XZP-H+Bru group， with six mice in each group. Pain behavior tests were conducted on the mice to assess pain levels. Colorimetric assays were employed to measure ferroptosis-related factors in serum and spinal cord tissue including Fe， malondialdehyde （MDA）， reactive oxygen species （ROS）， and superoxide dismutase （SOD）. Immunofluorescence staining was used to assess ROS production in spinal cord tissue. Transmission electron microscopy was used to observe the ultrastructure of mitochondria in lumbar spinal cord tissue. Quantitative real-time polymerase chain reaction （Real-time PCR） was employed to detect mRNA expression of Nrf2， heme oxygenase-1 （HO-1）， glutathione peroxidase 4 （GPX4）， and solute carrier family 7 member 11 （SLC7A11） in spinal cord neuron tissue. The protein expression of Nrf2， HO-1， GPX4， and SLC7A11 in spinal cord neurons was measured by Western blot. ResultsCompared with the Sham group， mice in the BCP group exhibited significantly reduced limb usage scores， mechanical foot withdrawal thresholds， and thermal foot withdrawal thresholds （P<0.01）. Serum and lumbar spinal cord tissue levels of Fe， MDA， and reactive oxygen species （ROS） were significantly elevated （P<0.05）， while superoxide dismutase （SOD） levels were significantly decreased （P<0.05）. Lumbar spinal cord mitochondrial structural damage was observed， and mRNA and protein expression of Nrf2， HO-1， GPX4， and SLC7A11 were significantly downregulated （P<0.01）. Compared with the BCP group， both low- and high-dose XZP groups improved the aforementioned pain behavioral indicators （P<0.05，P<0.01）， reduced ferroptosis-related biomarkers including Fe， MDA， and ROS levels （P<0.05）， increased SOD levels （P<0.05，P<0.01）， alleviated mitochondrial damage， and upregulated Nrf2， HO-1， GPX4， SLC7A11 mRNA and protein expression （P<0.05，P<0.01）. The high-dose XZP group exhibited comparable efficacy to Fer-1 in alleviating pain and inhibiting ferroptosis. Following Bru administration， XZP's effects on pain behavioral indicators， regulation of ferroptosis-related markers， mitochondrial structural protection， and activation of the Nrf2/HO-1/GPX4/SLC7A11 pathway were significantly reversed （P<0.05，P<0.01）. ConclusionExternal application of XZP alleviates pain symptoms in BCP mice by activating the Nrf2/HO-1/GPX4/SLC7A11 pathway， thereby inhibiting ferroptosis and neuronal damage in spinal cord neurons.

Pain， as one of the most common symptoms in cancer patients， seriously affects the survival quality of patients. The three-step pain relief program currently used in clinical practice cannot completely relieve pain in cancer patients and is accompanied by many problems. From the perspective of Jueyin syndrome in traditional Chinese medicine （TCM）， this paper believed that the core pathogenesis of cancer pain was declined healthy Qi and cold and heat in complexity， and used Wumeiwan as the main formula with modification according to syndrome for clearing the upper， warming the lower part of the body， and harmonizing the cold and heat. It can regulate the pathological environment of deficiency， cold， stasis， toxicity， and heat， and restore the physiological function of Yang transforming Qi while Yin constituting form， so as to prevent， relieve， and even eliminate cancer pain， having achieved good clinical efficacy. It can not only help cancer patients relieve pain， but also control tumor and eliminate tumor， achieving a dual benefit of pain relief and tumor suppression. It gives full play to the characteristics and advantages of syndrome differentiation and treatment in TCM， and expands the scope of ZHANG Zhongjing's treatment for Jueyin syndrome， which provides ideas for the clinical diagnosis and treatment of cancer pain from the perspective of deficiency-excess in complexity and cold and heat in complexity.

Objective To construct an index system for assessment of schistosomiasis transmission risk following natural disasters such as rainstorms, floods, earthquakes, mudslides, and landslides, so as to provide insights into rapid identification of schistosomiasis transmission risk post-disasters and formulation of targeted schistosomiasis control strategies. Methods An initial framework for the index system for assessment of schistosomiasis transmission risk following natural disasters was drafted through literature review, brainstorming, and focus group discussions. Two rounds of expert correspondence consultations were conducted using the Delphi method to refine and finalize the system, and the degrees of expert activeness, authority and endorse ment, and consensus were evaluated. In addition, the weights of each index were calculated using the analytic hierarchy process. Results A total of 18 experts participated in the consultation. The expert positive coefficients were 100.00% and 94.44% for two rounds of consultations, with authority coefficients of 0.92 and 0.94, respectively. The coefficients of coordination on the index importance, rationality and operability were 0.209, 0.185, 0.222 and 0.407, 0.214, 0.257 for two rounds of consultations, respectively, and all consistency tests were statistically significant (χ² = 246.771 to 505.278, all P values < 0.001). Following two rounds of expert consultations, an index system consisting of 6 first-level indicators, 15 second-level indicators, and 49 third-level indicators was ultimately constructed. In terms of first-level indicators, “disaster situation”, “previous epidemics”, “healthcare guarantee”, “response capacity” and “emergency recovery” had the highest weights, each at 18.18%. Regarding second-level indicators, “Schistosoma japonicum infections in animals”, “S. japonicum infections in snails” and “medical treatment” had the highest weights, each at 7.35%. In terms of third-level indicators, ten items had the highest weights, including “identification of schistosomiasis cases”, “detection of S. japonicum infections in wild feces”, “detection of S. japonicum infections in snails”, “reserves of schistosomiasis diagnostic/testing reagents and consumables”, “reserves of chemotherapy agents for human and animal schistosomiasis”, “reserves of cercariacides”, “periodical surveillance on schistosomiasis”, “identification of schistosomiasis transmission risk and timely response”, “normal provision of diagnosis and treatment services” and “post-disaster schistosomiasis surveillance”, each at 2.40%. Conclusion A scientific, systematic, and practical index system has been constructed for assessment of schistosomiasis transmission risk following natural disasters, which may provide insights into rapid post-disaster identification of schistosomiasis transmission risk, formulation of targeted schistosomiasis control strategies and optimization of resource allocation.

ObjectiveTo analyze the characteristics of 150 patients with spinal cord injury complicated with spasticity. MethodsA cross-sectional survey was conducted on 150 patients with spinal cord injury accompanied by spasticity from September, 2019 to December, 2024. Their age, gender, cause of injury, injury site, severity of injury, spasticity severity and other indicators were recorded. The relationships between different characteristics were analyzed, and a correlation analysis of disease duration, spasticity grade, injury level, injury severity and age were conducted. ResultsThere was no significant difference in age distribution between patients with tetraplegia and paraplegia (Z = 0.806, P = 0.420). The proportions of trauma (χ² = 3.982, P = 0.046) and tetraplegia (χ² = 10.559, P = 0.010) were higher in males than in females. Trauma was the main cause of injury in both tetraplegia and paraplegia patients; the proportion of tetraplegia was higher than paraplegia in trauma patients, while paraplegia was higher than tetraplegia in non-trauma patients (χ² = 11.885, P < 0.001). Patients with tetraplegia was dominated by incomplete injury, whereas patients with paraplegia was dominated by complete injury (χ² = 10.885, P = 0.012). Grade A injury was predominant in trauma patients (P = 0.003). Spasticity grade showed a very weak positive correlation with disease duration (r = 0.175, P = 0.032) and age (r = 0.168, P = 0.040). Injury severity showed a very weak positive correlation with age (r = 0.183, P = 0.025). ConclusionCharacteristics of patients with spinal cord injury complicated with spasticity is different with gender, cause of injury, injury level, injury severity.

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.

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.