Marček Peter, Kadlic Pavol, Adamová Louise-Mária, Tóthova Ľubomíra, Pastorek Michal, Kovalčíkova Alexandra Gaál, Valkovič Peter, Minár Michal, Slezáková Darina
Second Department of Neurology, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia.
Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia.
Mol Neurobiol. 2025 Apr 8. doi: 10.1007/s12035-025-04907-4.
Neuroinflammation plays a critical role in the pathophysiology of multiple sclerosis (MS), involving complex interactions between reactive oxygen species (ROS), cytokines, chemokines, and immune cells. Among these, neutrophils contribute to sustained inflammation through degranulation, ROS production, and the release of neutrophil extracellular traps (NETs). Extracellular DNA (ecDNA), a key component of NETs, may act as an autoantigen, promoting chronic inflammation and tissue damage. Additionally, impaired NETs and ecDNA degradation by deoxyribonucleases (DNases) may contribute to persistence of inflammation. The aim of the present study was to determine the levels of ecDNA and DNase activity in both blood plasma and cerebrospinal fluid (CSF) in newly diagnosed, treatment-naïve adult patients with relapsing-remitting MS and whether it correlates with disease severity and inflammatory activity in MS. Fifty-one treatment-naïve relapsing-remitting MS patients without disease-modifying therapy and 16 healthy controls (HC) were included in our study. Blood and CSF samples were analyzed for ecDNA, mitochondrial DNA (mtDNA) levels, and DNase activity. Correlations with inflammatory cytokines, oxidative stress, MRI lesion burden, and the expanded disability status scale (EDSS) were analyzed. MS patients exhibited significantly elevated ecDNA levels and reduced DNase activity in blood plasma compared to HC. EcDNA levels positively correlated with inflammatory cytokines, oxidative stress, and disease severity (EDSS). Furthermore, ecDNA and mtDNA levels in CSF positively correlated with inflammatory gadolinium-enhancing MRI lesions. Interestingly, no DNase activity was detected in CSF in both MS patients and HC. Our findings demonstrate that MS patients exhibit significantly elevated ecDNA levels and reduced DNase activity in blood plasma, which correlate with inflammatory cytokines, oxidative stress, and disease severity (EDSS). Additionally, increased ecDNA and mtDNA levels in CSF are associated with higher inflammatory activity, as reflected by gadolinium-enhancing MRI lesions. Considering the pro-inflammatory nature of ecDNA in perpetuating sterile inflammation, these results suggest a potential role of circulating nucleic acids in MS pathogenesis. Furthermore, impaired DNase activity may contribute to the persistence of ecDNA, potentially sustaining pro-inflammatory state in MS. Nevertheless, it remains unclear whether elevated ecDNA actively contributes to neuroinflammation or simply reflects ongoing immune activation. Further research is needed to elucidate the mechanisms underlying ecDNA release and degradation and its implications in MS progression.
神经炎症在多发性硬化症（MS）的病理生理学中起着关键作用，涉及活性氧（ROS）、细胞因子、趋化因子和免疫细胞之间的复杂相互作用。其中，中性粒细胞通过脱颗粒、ROS产生以及释放中性粒细胞胞外陷阱（NETs），促使炎症持续存在。细胞外DNA（ecDNA）是NETs的关键组成部分，可能作为自身抗原，促进慢性炎症和组织损伤。此外，脱氧核糖核酸酶（DNases）对NETs和ecDNA的降解受损可能导致炎症持续存在。本研究的目的是测定新诊断的、未接受过治疗的复发缓解型成年MS患者血浆和脑脊液（CSF）中ecDNA的水平和DNase活性，以及它们是否与MS的疾病严重程度和炎症活动相关。我们的研究纳入了51例未接受疾病修饰治疗的复发缓解型MS患者和16名健康对照（HC）。对血液和脑脊液样本进行ecDNA、线粒体DNA（mtDNA）水平以及DNase活性分析。分析了其与炎症细胞因子、氧化应激、MRI病变负荷以及扩展残疾状态量表（EDSS）的相关性。与HC相比，MS患者血浆中的ecDNA水平显著升高，DNase活性降低。EcDNA水平与炎症细胞因子、氧化应激和疾病严重程度（EDSS）呈正相关。此外，CSF中的ecDNA和mtDNA水平与炎症性钆增强MRI病变呈正相关。有趣的是，在MS患者和HC的CSF中均未检测到DNase活性。我们的研究结果表明，MS患者血浆中的ecDNA水平显著升高，DNase活性降低，这与炎症细胞因子、氧化应激和疾病严重程度（EDSS）相关。此外，CSF中ecDNA和mtDNA水平升高与更高的炎症活动相关，如钆增强MRI病变所示。鉴于ecDNA在维持无菌性炎症中的促炎性质，这些结果表明循环核酸在MS发病机制中可能发挥作用。此外，DNase活性受损可能导致ecDNA持续存在，可能维持MS中的促炎状态。然而，目前尚不清楚ecDNA升高是积极促成神经炎症还是仅仅反映正在进行的免疫激活。需要进一步研究以阐明ecDNA释放和降解的潜在机制及其在MS进展中的意义。
