Minigene Pharmacy Laboratory, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.
Appl Microbiol Biotechnol. 2017 Oct;101(20):7653-7662. doi: 10.1007/s00253-017-8480-5. Epub 2017 Sep 9.
Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by the self-destruction of insulin-producing β cells. Recently, studies have revealed that neutrophils contribute to the early pathological injury to the pancreas, predominantly via the formation of neutrophil extracellular traps (NETs). To determine whether early intervention targeting NETs with staphylococcal nuclease (SNase) can delay the onset of T1DM, non-obese diabetic (NOD) mice were orally administered recombinant Lactococcus lactis (L. lactis) expressing SNase. The results showed that NETs were effectively disrupted by SNase both in vivo and in vitro, leading to a significant decrease in neutrophil-derived circulating free DNA (cf-DNA/NETs), neutrophil elastase (NE), and protease 3 (PR3) in the serum compared with the controls. In addition, SNase effectively regulated the blood glucose levels of NOD mice, and the onset of diabetes was postponed with reduced mortality and morbidity. Recombinant L. lactis also ameliorated inflammation in NOD mice, as evidenced by the remarkable increase in IL-4 and reductions in TNF-α and CRP. Moreover, HE staining results showed that L. lactis expressing SNase exerted protective effects on pancreatic islets and relieved inflammation of the small intestine in NOD mice. Hence, the present study indicates that the oral delivery of SNase by L. lactis can effectively prevent T1DM, ameliorate inflammation, and contribute to immunomodulatory balance in NOD mice.
1 型糖尿病（T1DM）是一种自身免疫性疾病，其特征是胰岛素产生β细胞的自身破坏。最近的研究表明，中性粒细胞通过形成中性粒细胞胞外诱捕网（NETs），促进胰腺的早期病理损伤。为了确定用金黄色葡萄球菌核酸酶（SNase）靶向 NETs 的早期干预是否可以延迟 T1DM 的发病，非肥胖型糖尿病（NOD）小鼠口服给予表达 SNase 的重组乳球菌（L. lactis）。结果表明，SNase 可有效在体内和体外破坏 NETs，导致与对照组相比，血清中中性粒细胞来源的循环游离 DNA（cf-DNA/NETs）、中性粒细胞弹性蛋白酶（NE）和蛋白酶 3（PR3）显著减少。此外，SNase 可有效调节 NOD 小鼠的血糖水平，降低死亡率和发病率，从而延迟糖尿病的发病。重组乳球菌还改善了 NOD 小鼠的炎症，IL-4 显著增加，TNF-α 和 CRP 减少。此外，HE 染色结果表明，表达 SNase 的乳球菌对胰岛具有保护作用，并缓解 NOD 小鼠的小肠炎症。因此，本研究表明，L. lactis 表达的 SNase 经口服给药可有效预防 T1DM，改善炎症，并有助于 NOD 小鼠的免疫调节平衡。
