Purpose

Primary Sjögren's syndrome (pSS) is an autoimmune disease that mainly attacks the lacrimal glands causing severe aqueous-deficient dry eye. Clinical evidence indicates the DNA sensing mechanism in the pathogenesis of pSS. The purpose of the present study is to determine the pro-inflammatory effect of self-genomic DNA (gDNA) on myoepithelial cells (MECs), which along with acinar and ductal cells is a major cell type of the lacrimal gland.

Method

MECs primary culture was acquired from female C57BL6J mice. Genomic DNA was extracted from the spleen of the same animal. The MECs were challenged with self-gDNA. The cytokine secretion was detected using supernatant by enzyme-linked immunosorbent assay (ELISA). The activation of inflammasomes was determined using FAM-FLICA. Cryosections of NOD.B10.H2^b mouse model of pSS were obtained for immunofluorescence microscopy (IF), with Balb/C as control.

Result

Treatment with gDNA activated AIM2 inflammasome assembly and function, leading to secretion of interleukin (IL)-1β and IL-18 in MECs. The stimulation of IL-1β secretion by gDNA appeared to be solely at the post-translational level, whereas IL-18 secretion was a combination of increased protein synthesis and post-translational modification. Genomic DNA also induced the activation of STimulators of INterferon Genes (STING), which correlated to the activation of STING in the lacrimal gland from the NOD.B10.H2^b mouse. STING activation led to the secretion of IFN-β via Nuclear Factor-κB (NF-κB). The IFN-β further enhances the secretion of IL-1β. The contractility of MECs was disabled by treatment with gDNA or poly AnT, independent of the level of intracellular [Ca²⁺].

Conclusion

Self-gDNA induces a proinflammatory response in lacrimal gland MECs by activating both the AIM2 inflammasome and STING and thus may contribute to the pathogenesis of pSS.

中文翻译：

---

基因组DNA激活AIM2炎症小体和STING通路诱导泪腺肌上皮细胞炎症

目的

原发性干燥综合征 (pSS) 是一种自身免疫性疾病，主要攻击泪腺，导致严重缺水性干眼症。临床证据表明 DNA 传感机制在 pSS 的发病机制中。本研究的目的是确定自身基因组 DNA (gDNA) 对肌上皮细胞 (MEC) 的促炎作用，肌上皮细胞与腺泡和导管细胞一起是泪腺的主要细胞类型。

方法

MEC 原代培养物是从雌性 C57BL6J 小鼠中获得的。从同一动物的脾脏中提取基因组 DNA。MEC 受到自身 gDNA 的挑战。使用上清液通过酶联免疫吸附测定（ELISA）检测细胞因子的分泌。使用 FAM-FLICA 测定炎症小体的激活。获得 pSS NOD.B10.H2 ^{b小鼠模型的冷冻切片用于免疫荧光显微镜 (IF)，以 Balb/C 作为对照。}

结果

gDNA 处理激活 AIM2炎性体组装和功能，导致MEC 中白细胞介素 (IL)-1β 和 IL-18 的分泌。gDNA 对 IL-1β 分泌的刺激似乎仅在翻译后水平，而 IL-18 分泌是蛋白质合成增加和翻译后修饰的组合。基因组 DNA 还诱导干扰素基因 ST 刺激器 (STING) 的激活^{，这与 NOD.B10.H2 b小鼠}泪腺中 STING 的激活相关。STING 激活导致通过核因子-κB (NF-κB) 分泌 IFN-β。IFN-β进一步增强IL-1β的分泌。^{通过 gDNA 或聚 AnT 处理，MEC 的收缩性被禁用，与细胞内 [Ca 2+ ]}的水平无关。

结论

自身 gDNA 通过激活 AIM2 炎性体和 STING 诱导泪腺 MEC 中的促炎反应，因此可能有助于 pSS 的发病机制。