Chen Jinji, Liang Shengsheng, Li Cheng, Li Bowen, He Mingdong, Li Kezhen, Fu Weijin, Li Shenghua, Mi Hua
Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China.
Inflamm Res. 2025 Jan 7;74(1):6. doi: 10.1007/s00011-024-01973-7.
Mitochondrial dysfunction and damage can result in the release of mitochondrial DNA (mtDNA) into the cytoplasm, which subsequently activates the cGAS-STING pathway, promoting the onset of inflammatory diseases. Various factors, such as oxidative stress, viral infection, and drug toxicity, have been identified as inducers of mitochondrial damage. This study aims to investigate the role of mtDNA as a critical inflammatory mediator in the pathogenesis of ketamine (KET)-induced cystitis (KC) through the cGAS-STING pathway.
To investigate the role of the cGAS-STING pathway in KET-induced cystitis, we assessed the expression of cGAS and STING in rats with KET cystitis. Additionally, we evaluated STING expression in conditionally deficient Simian Virus-transformed Human Uroepithelial Cell Line 1 (SV-HUC-1) cells in vitro. Morphological changes in mitochondria were examined using transmission electron microscopy. We measured intracellular reactive oxygen species (ROS) production through flow cytometry and immunofluorescence techniques. Furthermore, alterations in associated inflammatory factors and cytokines were quantified using real-time quantitative PCR with fluorescence detection.
We observed up-regulation of cGAS and STING expressions in the bladder tissue of rats in the KET group, stimulation with KET also led to increased cGAS and STING levels in SV-HUC-1 cells. Notably, the knockdown of STING inhibited the nuclear translocation of NF-κB p65 and IRF3, resulting in a decrease in the expression of inflammatory cytokines, including IL-6, IL-8, and CXCL10. Additionally, KET induced damage to the mitochondria of SV-HUC-1 cells, facilitating the release of mtDNA into the cytoplasm. This significant depletion of mtDNA inhibited the activation of cGAS-STING pathway, subsequently affecting the expression of NF-κB p65 and IRF3. Importantly, the reintroduction of mtDNA after STING knockdown partially restored the inflammatory response.
Our findings confirmed the activation of the cGAS-STING pathway in KC rats and revealed mitochondrial damage in vitro. These results highlight the involvement of the cGAS-STING pathway in the pathogenesis of KC, suggesting its potential as a therapeutic target for intervention.
线粒体功能障碍和损伤可导致线粒体DNA（mtDNA）释放到细胞质中，随后激活cGAS-STING通路，促进炎症性疾病的发生。氧化应激、病毒感染和药物毒性等多种因素已被确定为线粒体损伤的诱导因素。本研究旨在通过cGAS-STING通路探讨mtDNA作为关键炎症介质在氯胺酮（KET）诱导的膀胱炎（KC）发病机制中的作用。
为了研究cGAS-STING通路在KET诱导的膀胱炎中的作用，我们评估了KET膀胱炎大鼠中cGAS和STING的表达。此外，我们在体外评估了条件性缺陷的猿猴病毒转化的人尿道上皮细胞系1（SV-HUC-1）细胞中STING的表达。使用透射电子显微镜检查线粒体的形态变化。我们通过流式细胞术和免疫荧光技术测量细胞内活性氧（ROS）的产生。此外，使用荧光检测的实时定量PCR对相关炎症因子和细胞因子的变化进行定量。
我们观察到KET组大鼠膀胱组织中cGAS和STING表达上调，用KET刺激也导致SV-HUC-1细胞中cGAS和STING水平升高。值得注意的是，敲低STING抑制了NF-κB p65和IRF3的核转位，导致包括IL-6、IL-8和CXCL10在内的炎症细胞因子表达降低。此外，KET诱导SV-HUC-1细胞线粒体损伤，促进mtDNA释放到细胞质中。mtDNA的这种显著消耗抑制了cGAS-STING通路的激活，随后影响NF-κB p65和IRF3的表达。重要的是，在敲低STING后重新引入mtDNA部分恢复了炎症反应。
我们的研究结果证实了KC大鼠中cGAS-STING通路的激活，并揭示了体外线粒体损伤。这些结果突出了cGAS-STING通路在KC发病机制中的参与，表明其作为干预治疗靶点的潜力。
