Marumo Takeshi, Hoshino Junichi, Kawarazaki Wakako, Nishimoto Mitsuhiro, Ayuzawa Nobuhiro, Hirohama Daigoro, Yamanouchi Masayuki, Ubara Yoshifumi, Okaneya Toshikazu, Fujii Takeshi, Yuki Kazunari, Atsumi Yoshihito, Sato Atsuhisa, Arai Eri, Kanai Yae, Shimosawa Tatsuo, Fujita Toshiro
Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan
Department of Pharmacology, School of Medicine, International University of Health and Welfare, Narita, Chiba, Japan.
BMJ Open Diabetes Res Care. 2020 Sep;8(1). doi: 10.1136/bmjdrc-2020-001501.
Renal tubular injury contributes to the decline in kidney function in patients with diabetes. Cell type-specific DNA methylation patterns have been used to calculate proportions of particular cell types. In this study, we developed a method to detect renal tubular injury in patients with diabetes by detecting exfoliated tubular cells shed into the urine based on tubular cell-specific DNA methylation patterns.
We identified DNA methylation patterns specific for human renal proximal tubular cells through compartment-specific methylome analysis. We next determined the methylation levels of proximal tubule-specific loci in urine sediment of patients with diabetes and analyzed correlation with clinical variables.
We identified genomic loci in and to be selectively unmethylated in human proximal tubular cells. The methylation levels of and in urine sediment, deemed to reflect the proportion of exfoliated proximal tubular cells due to injury, correlated well with each other. Methylation levels of in urine sediment significantly correlated with the annual decline in estimated glomerular filtration rate. Moreover, addition of urinary methylation to a model containing known risk factors significantly improved discrimination of patients with diabetes with faster estimated glomerular filtration rate decline.
This study demonstrates that patients with diabetes with continual loss in kidney function may be stratified by a specific DNA methylation signature through epigenetic urinalysis and provides further evidence at the level of exfoliated cells in the urine that injury of proximal tubular cells may contribute to pathogenesis of diabetic kidney disease.
肾小管损伤会导致糖尿病患者肾功能下降。细胞类型特异性DNA甲基化模式已被用于计算特定细胞类型的比例。在本研究中，我们开发了一种基于肾小管细胞特异性DNA甲基化模式，通过检测尿液中脱落的肾小管细胞来检测糖尿病患者肾小管损伤的方法。
我们通过特定区域甲基化组分析确定了人类肾近端小管细胞特异性的DNA甲基化模式。接下来，我们测定了糖尿病患者尿沉渣中近端小管特异性位点的甲基化水平，并分析其与临床变量的相关性。
我们确定了人类近端肾小管细胞中选择性去甲基化的基因组位点。尿沉渣中这些位点的甲基化水平，被认为反映了因损伤而脱落的近端肾小管细胞的比例，两者之间具有良好的相关性。尿沉渣中该位点的甲基化水平与估计肾小球滤过率的年下降率显著相关。此外，将尿中该位点甲基化加入包含已知危险因素的模型中，可显著改善对估计肾小球滤过率下降较快的糖尿病患者的鉴别。
本研究表明，通过表观遗传学尿液分析，可利用特定的DNA甲基化特征对肾功能持续下降的糖尿病患者进行分层，并在尿液脱落细胞水平上进一步证明近端肾小管细胞损伤可能参与糖尿病肾病的发病机制。
