Chen Jing, Zhang Xiaoyan, Zhang Han, Liu Tongqiang, Zhang Hui, Teng Jie, Ji Jun, Ding Xiaoqiang
Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.; Kidney and Dialysis Institute of Shanghai, Shanghai, China.; Kidney and Blood Purification Laboratory of Shanghai, Shanghai, China.
Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.
Int J Biol Sci. 2016 Sep 15;12(10):1236-1246. doi: 10.7150/ijbs.15195. eCollection 2016.
Chronic kidney disease (CKD) is a state of Klotho deficiency. The Klotho expression may be suppressed due to DNA hypermethylation in cancer cells so we have investigated the effects and possible mechanisms by which Klotho expression is regulated in human aortic smooth muscle cells (HASMCs). The vascular Klotho hypermethylation in radial arteries of patients with end-stage renal disease was described. Cultured HASMCs and 5/6-nephrectomized Sprague Dawley (SD) rats treated with indoxyl sulfate (IS) were used as and models, respectively. IS increased CpG hypermethylation of the Klotho gene and decreased Klotho expression in HASMCs, and potentiated HASMCs calcification. The expression of DNA methyltransferase (DNMT) 1 and 3a in HASMCs treated with IS was significantly increased and specific inhibition of DNA methyltransferase 1 by 5-aza-2'-deoxycytidine(5Aza-2dc) caused demethylation of the Klotho gene and increased Klotho expression. In rats, injection of IS potentiated vascular calcification, increased CpG hypermethylation of the Klotho gene and decreased Klotho expression in the aortic medial layer and all of these changes could be reverted by 5Aza-2dc treatment. Transcriptional suppression of vascular Klotho gene expression by IS and epigenetic modification of Klotho by IS may be an important pathological mechanism of vascular calcification in CKD.
慢性肾脏病（CKD）是一种Klotho缺乏状态。由于癌细胞中的DNA高甲基化，Klotho表达可能受到抑制，因此我们研究了人主动脉平滑肌细胞（HASMCs）中Klotho表达的调控作用及可能机制。描述了终末期肾病患者桡动脉中的血管Klotho高甲基化情况。分别将培养的HASMCs和用硫酸吲哚酚（IS）处理的5/6肾切除的Sprague Dawley（SD）大鼠作为 和 模型。IS增加了HASMCs中Klotho基因的CpG高甲基化并降低了Klotho表达，并增强了HASMCs的钙化。用IS处理的HASMCs中DNA甲基转移酶（DNMT）1和3a的表达显著增加，用5-氮杂-2'-脱氧胞苷（5Aza-2dc）特异性抑制DNA甲基转移酶1导致Klotho基因去甲基化并增加Klotho表达。在大鼠中，注射IS增强了血管钙化，增加了主动脉中层Klotho基因的CpG高甲基化并降低了Klotho表达，而所有这些变化都可以通过5Aza-2dc处理逆转。IS对血管Klotho基因表达的转录抑制以及IS对Klotho的表观遗传修饰可能是CKD中血管钙化的重要病理机制。
