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Journal of Diabetes Research
Volume 2014, Article ID 761938, 7 pages
http://dx.doi.org/10.1155/2014/761938
Research Article

Ethnic Differences in MicroRNA-375 Expression Level and DNA Methylation Status in Type 2 Diabetes of Han and Kazak Populations

1Departments of Endocrinology and Metabolism, First Affiliated Hospital, Shihezi University School of Medicine, Shihezi, Xinjiang 832002, China
2Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
3Shihezi University School of Medicine, Shihezi, Xinjiang 832002, China
4The Central Laboratory, First Affiliated Hospital, Shihezi University School of Medicine, Shihezi, Xinjiang 832002, China

Received 9 November 2013; Revised 24 January 2014; Accepted 8 February 2014; Published 11 March 2014

Academic Editor: Chen Li

Copyright © 2014 Xiangyun Chang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Han population is six times as likely as Kazak population to present with type 2 diabetes mellitus (T2DM) in China. We hypothesize that differential expression and CpG methylation of miR-375 may be an ethnic-related factor that influences the incidence of T2DM. The expression level of miR-375 was examined using real-time PCR on Kazak and Han T2DM plasma samples. Furthermore, the methylation levels of CpG sites of miR-375 promoter were determined by MassARRAY Spectrometry in these samples. The relative expression levels of plasma miR-375 in Kazak T2DM samples are 1, and the relative expression levels of plasma miR-375 in Han T2DM samples are 3. The mean level of miR-375 methylation, calculated from the methylation levels of the CpG sites, was 8.47% for the Kazak T2DM group and 10.38% for the Han T2DM group. Further, five CpG units showed a statistically significant difference between Kazak and Han T2DM samples, and, among them, four were hypomethylated and only one CpG unit showed hypermethylation in Kazak T2DM samples. These findings indicate that the expression levels of plasma miR-375 and its CpG methylation in the promoter region are ethnically different, which may contribute to the different incidence of diabetes observed in Kazak and Han populations.