Jung Dongju, Xu Yuechi, Sun Zhongjie
Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
Current address: Department of Biomedical Laboratory Science, Hoseo University, Chungnam, Republic of Korea.
Oncotarget. 2017 Jul 18;8(29):46745-46755. doi: 10.18632/oncotarget.18608.
Klotho (KL) is described as an anti-aging gene because mutation of Kl gene leads to multiple pre-mature aging phenotypes and shortens lifespan in mice. Growing evidence suggests that an increase in KL expression may be beneficial for age-related diseases such as arteriosclerosis and diabetes. It remains largely unknown, however, how Kl expression could be induced. Here we discovered novel molecular mechanism for induction of Kl expression with a small molecule 'Compound H', N-(2-chlorophenyl)-1H-indole-3-caboxamide. Compound H was originally identified through a high-throughput screening of small molecules for identifying Kl inducers. However, how Compound H induces Kl expression has never been investigated. We found that Compound H increased Kl expression via demethylation in CpG islands of the Kl gene. The demethylation was accomplished by activating demethylases rather than inhibiting methylases. Due to demethylation, Compound H enhanced binding of transcription factors, Pax4 and Kid3, to the promoter of the Kl gene. Pax4 and Kid3 regulated Kl promoter activity positively and negatively, respectively. Thus, our results show that demethylation is an important molecular mechanism that mediates Compound H-induced Kl expression. Further investigation is warranted to determine whether Compound H demethylates the Kl gene in vivo and whether it can serve as a therapeutic agent for repressing or delaying the onset of age-related diseases.
klotho（KL）被描述为一种抗衰老基因，因为Kl基因的突变会导致多种早衰表型，并缩短小鼠的寿命。越来越多的证据表明，KL表达的增加可能对动脉粥样硬化和糖尿病等与年龄相关的疾病有益。然而，Kl表达是如何被诱导的，在很大程度上仍然未知。在这里，我们发现了一种小分子“化合物H”，即N-(2-氯苯基)-1H-吲哚-3-甲酰胺，诱导Kl表达的新分子机制。化合物H最初是通过对小分子进行高通量筛选以鉴定Kl诱导剂而被发现的。然而，化合物H如何诱导Kl表达从未被研究过。我们发现化合物H通过Kl基因CpG岛的去甲基化增加了Kl的表达。这种去甲基化是通过激活去甲基化酶而不是抑制甲基化酶来实现的。由于去甲基化，化合物H增强了转录因子Pax4和Kid3与Kl基因启动子的结合。Pax4和Kid3分别对Kl启动子活性起正向和负向调节作用。因此，我们的结果表明去甲基化是介导化合物H诱导Kl表达的重要分子机制。有必要进一步研究化合物H在体内是否能使Kl基因去甲基化，以及它是否可以作为一种治疗剂来抑制或延缓与年龄相关疾病的发生。
