Aberrant DNA methylation of mTOR pathway genes promotes inflammatory activation of immune cells in diabetic kidney disease
Aberrant DNA methylation of mTOR pathway genes promotes inflammatory activation of immune cells in diabetic kidney disease
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mTOR 通路基因的异常 DNA 甲基化促进糖尿病肾病免疫细胞的炎症激活
DOI：
10.1016/j.kint.2019.02.020
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发表时间：
2019-08-01
影响因子：
19.6
通讯作者：
Dong, Zheng
中科院分区：
文献类型：
--
作者：
Chen, Guochun;Chen, Huihui;Dong, Zheng
DNA甲基化与糖尿病肾病（DKD）的发病机制有关，但其潜在机制尚不清楚。在这项研究中，我们验证了外周免疫细胞中异常DNA甲基化有助于DKD进展的假设。我们发现DNA甲基化的关键酶DNA甲基化酶1 （DNMT1）水平随着DKD患者外周血单个核细胞炎症活性的增加而增加。5-Aza -2'-脱氧胞苷（5-Aza）对DNMT1的抑制作用显著增加了培养动物和糖尿病动物外周血单核细胞中CD4（+）和CD25（+）调节性T细胞的比例。5- aza处理动物的免疫细胞过继转移对宿主免疫系统有有益影响，导致DKD显著改善。利用全基因组DNA甲基化分析，我们在糖尿病患者外周血单个核细胞中发现了哺乳动物雷帕霉素靶蛋白（mTOR）调控因子启动子区域的差异甲基化胞嘧啶。此外，mRNA阵列证实了在mTOR通路中表达的基因的一致诱导。重要的是，通过RNA干扰下调DNMT1的表达导致mTOR负调节因子的胞嘧啶去甲基化和随后的mTOR活性降低。最后，mTOR的调节导致5-aza对糖尿病免疫细胞的作用发生变化。因此，糖尿病免疫细胞中DNMT1的上调诱导mTOR上游调控因子胞嘧啶甲基化异常，导致mTOR通路的致病性激活，并导致糖尿病肾脏炎症。因此，本研究强调了靶向免疫系统表观遗传事件治疗DKD的治疗潜力。
DNA methylation has been implicated in the pathogenesis of diabetic kidney disease (DKD), but the underlying mechanisms remain unclear. In this study, we tested the hypothesis that aberrant DNA methylation in peripheral immune cells contributes to DKD progression. We showed that levels of DNA methyltransferase 1 (DNMT1), a key enzyme for DNA methylation, were increased along with inflammatory activity of peripheral blood mononuclear cells in DKD patients. Inhibition of DNMT1 with 5-aza-2'-deoxycytidine (5-Aza) markedly increased the proportion of CD4(+)CD25(+) regulatory T cells in peripheral blood mononuclear cells in culture and in diabetic animals. Adoptive transfer of immune cells from 5-Aza-treated animals showed beneficial effects on the host immune system, resulting in a significant improvement of DKD. Using genome-wide DNA methylation assays, we identified the differentially methylated cytosines in the promoter regions of mammalian target of rapamycin (mTOR) regulators in peripheral blood mononuclear cells of diabetic patients. Further, mRNA arrays confirmed the consistent induction of genes expressed in the mTOR pathway. Importantly, down-regulation of DNMT1 expression via RNA interference resulted in prominent cytosine demethylation of mTOR negative regulators and subsequent decrease of mTOR activity. Lastly, modulation of mTOR resulted in changes in the effect of 5-aza on diabetic immune cells. Thus, up-regulation of DNMT1 in diabetic immune cells induces aberrant cytosine methylation of the upstream regulators of mTOR, leading to pathogenic activation of the mTOR pathway and consequent inflammation in diabetic kidneys. Hence, this study highlights therapeutic potential of targeting epigenetic events in immune system for treating DKD.