Mitochondrial DNA Activates the NLRP3 Inflammasome and Predisposes to Type 1 Diabetes in Murine Model.
Mitochondrial DNA Activates the NLRP3 Inflammasome and Predisposes to Type 1 Diabetes in Murine Model.
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DOI：
10.3389/fimmu.2017.00164
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发表时间：
2017
影响因子：
7.3
通讯作者：
Silva JS
中科院分区：
文献类型：
--
作者：
Carlos D;Costa FR;Pereira CA;Rocha FA;Yaochite JN;Oliveira GG;Carneiro FS;Tostes RC;Ramos SG;Zamboni DS;Camara NO;Ryffel B;Silva JS
虽然NLRP3基因多态与1型糖尿病(T1D)的易感性有关，但NLRP3炎症体在T1D中的潜在功能和激活尚不清楚。本研究表明，非肥胖糖尿病小鼠胰腺淋巴结(PLN)中NLRP3和前IL-1β基因表达增加。多次小剂量链脲佐菌素可诱导C57BL/6小鼠NLRP3、凋亡相关斑点样蛋白和前IL-1β基因表达上调。此外，糖尿病C57BL/6小鼠胰腺组织IL-1β蛋白表达在第7天升高，并持续到第15天。糖尿病小鼠PLN中caspase-1阳性巨噬细胞增多，经链脲佐菌素治疗后，NLRP3−/−小鼠的PLN中caspase-1阳性细胞数减少，而Asc−/−小鼠无此变化。与野生型(WT)糖尿病小鼠相比，NLRP3和IL-1R缺陷小鼠(而不是ASC缺陷小鼠)表现出糖尿病发病率降低、胰岛素炎症减少、高血糖降低和胰岛素水平正常。值得注意的是，这些小鼠在PLN中也表现出产生IL-17的CD_4和CD_8T细胞(Th17和Tc17)以及产生干扰素-γ的CD_4和CD_8T细胞(Th1和Tc1)减少。在STZ治疗诱导T1D后，NLRP3基因缺陷小鼠的PLN中髓系来源的抑制细胞和肥大细胞数量也增加，胰腺组织中IL-6、IL-10和IL-4的表达显著增加。有趣的是，糖尿病小鼠表现出与线粒体DNA相关的基因循环表达增加，如细胞色素b和细胞色素c，但没有NADH脱氢酶亚单位6(NADH)。糖尿病小鼠的线粒体DNA可显著诱导WT巨噬细胞产生IL-1β和激活Caspase-1，而NLRP3−/−巨噬细胞的IL-1和Caspase-1活性明显降低。最后，体内注射mDNA增加了PLN中的Th17/Tc17/Th1/Tc1细胞，并使T1D发作提前，而在NLRP3−/−小鼠中这一作用被取消。总之，我们的结果表明，mDNA介导的NLRP3激活触发了caspase-1依赖的IL-1β的产生，并在STZ诱导的T1D的发展过程中参与了致病细胞反应。
Although a correlation between polymorphisms of NOD-like receptor family-pyrin domain containing 3 (NLRP3) and predisposition to type 1 diabetes (T1D) has been identified, the potential function and activation of the NLRP3 inflammasome in T1D have not been clarified. The present study shows that non-obese diabetic mice exhibited increased NLRP3, and pro-IL-1β gene expression in pancreatic lymph nodes (PLNs). Similar increases in gene expression of NLRP3, apoptosis associated speck like protein (ASC) and pro-IL-1β were induced by multiple low doses of streptozotocin (STZ) in C57BL/6 mice. In addition, diabetic C57BL/6 mice also exhibited increased IL-1β protein expression in the pancreatic tissue at day 7, which remained elevated until day 15. Diabetic mice also showed increased positive caspase-1 macrophages in the PLNs, which were decreased in NLRP3−/− mice, but not in ASC−/− mice, after STZ treatment. NLRP3- and IL-1R-deficient mice, but not ASC-deficient mice, showed reduced incidence of diabetes, less insulitis, lower hyperglycemia, and normal insulin levels compared to wild-type (WT) diabetic mice. Notably, these mice also displayed a decrease in IL-17-producing CD4 and CD8 T cells (Th17 and Tc17) and IFN-γ-producing CD4 and CD8 T cells (Th1 and Tc1) in the PLNs. Following STZ treatment to induce T1D, NLRP3-deficient mice also exhibited an increase in myeloid-derived suppressor cell and mast cell numbers in the PLNs along with a significant increase in IL-6, IL-10, and IL-4 expression in the pancreatic tissue. Interestingly, diabetic mice revealed increased circulating expression of genes related to mitochondrial DNA, such as cytochrome b and cytochrome c, but not NADH dehydrogenase subunit 6 (NADH). Mitochondrial DNA (mDNA) from diabetic mice, but not from non-diabetic mice, induced significant IL-1β production and caspase-1 activation by WT macrophages, which was reduced in NLRP3−/− macrophages. Finally, mDNA administration in vivo increased Th17/Tc17/Th1/Tc1 cells in the PLNs and precipitated T1D onset, which was abolished in NLRP3−/− mice. Overall, our results demonstrate that mDNA-mediated NLRP3 activation triggers caspase-1-dependent IL-1β production and contributes to pathogenic cellular responses during the development of STZ-induced T1D.