Decreased N(6)-methyladenosine in peripheral blood RNA from diabetic patients is associated with FTO expression rather than ALKBH5

J Clin Endocrinol Metab. 2015 Jan;100(1):E148-54. doi: 10.1210/jc.2014-1893.

Abstract

Context: N(6)-methyladenosine (m(6)A) modification plays a fundamental role in the epigenetic regulation of the mammalian transcriptome. m(6)A can be demethylated by fat mass- and obesity-associated (FTO) protein and α-ketoglutarate-dependent dioxygenase alkB homolog 5 (ALKBH5) protein. However, the importance of m(6)A alteration in type 2 diabetes mellitus (T2DM) has not been explored.

Objective: The objective of the study was to investigate whether m(6)A content was reduced in T2DM patients and whether m(6)A content was correlated with the mRNA expression levels of the FTO and ALKBH5 genes.

Methods: In this case-control study, peripheral blood samples were obtained from 88 T2DM patients and 92 healthy controls. For the diabetic animal model experiment, blood samples were obtained from seven diabetic and eight nondiabetic rats. A sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry method was developed for the determination of the m(6)A content in RNA, quantitative real-time PCR was used to examine the mRNA expression levels of the FTO and ALKBH5 genes, and high-resolution melting and DNA sequencing were used to detect FTO single-nucleotide polymorphisms.

Results: Our results showed that the m(6)A contents in the RNA from T2DM patients and diabetic rats were significantly lower compared with the control groups (P = 2.6 × 10(-24) for T2DM patients; P = .001 for diabetic rats, respectively), and T2DM can be characterized by the content of m(6)A. The mRNA expression level of FTO was significantly higher in T2DM patients than that of the controls (P = .0007) and was associated with the risk of T2DM (odds ratio 2.797, 95% confidence interval 1.452-5.389, P = .002). Moreover, the m(6)A contents were correlated with FTO mRNA expression.

Conclusions: These data suggest that the increased mRNA expression of FTO could be responsible for the reduction of m(6)A in T2DM, which may further increase the risk of complications of T2DM. Low m(6)A should be investigated further as a novel potential biomarker of T2DM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / analogs & derivatives*
  • Adenosine / blood
  • AlkB Homolog 5, RNA Demethylase
  • Alpha-Ketoglutarate-Dependent Dioxygenase FTO
  • Animals
  • Biomarkers / blood
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / genetics
  • Diabetes Mellitus, Type 2 / metabolism*
  • Dioxygenases / genetics
  • Dioxygenases / metabolism*
  • Epigenesis, Genetic
  • Female
  • Humans
  • Male
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Proteins / genetics
  • Proteins / metabolism*
  • Rats

Substances

  • Biomarkers
  • Membrane Proteins
  • Proteins
  • N-methyladenosine
  • Dioxygenases
  • ALKBH5 protein, human
  • AlkB Homolog 5, RNA Demethylase
  • Alpha-Ketoglutarate-Dependent Dioxygenase FTO
  • FTO protein, human
  • Adenosine

Grants and funding

This work was supported by the National Natural Science Foundation of China (Grants 81271919 and 81472023) (to S.-M.L.); the National Basic Research Program of China (973 Program) (Grant 2012CB720605) (to S.-M.L.); the National Basic Research Program of China (973 Program) Grant 2012CB720603 (to B.-F.Y.); the National Natural Science Foundation of China (Grants 21205091 and 21228501) (to B.-F.Y.); the National Basic Research Program of China (973 Program) Grant 2012CB720601 (to Y.-Q.F.); and the National Natural Science Foundation of China (Grants 91017013 and 91217309) (to Y.-Q.F.).