Vitamin B₁₂Supplementation Influences Methylation of Genes Associated with Type 2 Diabetes and Its Intermediate Traits

Abstract

Aim: To investigate the effect of B₁₂ and/or folic acid supplementation on genome-wide DNA methylation. Methods: We performed Infinium HumanMethylation450 BeadChip (Zymo Research, CA, USA) assay in children supplemented with B₁₂ and/or folic acid (n = 12 in each group) and investigated the functional mechanism of selected differentially methylated loci. Results: We noted significant methylation changes postsupplementation in B₁₂ (589 differentially methylated CpGs and 2892 regions) and B₁₂ + folic acid (169 differentially methylated CpGs and 3241 regions) groups. Type 2 diabetes-associated genes TCF7L2 and FTO; and a miRNA, miR21 were further investigated in another B₁₂-supplementation cohort. We also demonstrate that methylation influences miR21 expression and FTO, TCF7L2, CREBBP/CBP and SIRT1 are direct targets of miR21-3p. Conclusion: B₁₂ supplementation influences regulation of several metabolically important Type 2 diabetes-associated genes through methylation of miR21. Hence, our study provides novel epigenetic explanation for the association between disordered one carbon metabolism and risk of adiposity, insulin resistance and diabetes and has translational potential.

Keywords::

•  DNA methylation
• folic acid
• miRNAs
• molecular mechanisms
• supplementation
• Type 2 diabetes
• vitamin B₁₂

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at: www.tandfonline.com/doi/suppl/10.2217/epi-2017-0102.

Author contributions

CS Yajnik and GR Chandak conceptualized and planned the study with significant intellectual contribution from CHD Fall and KA Lillycrop. DK Yadav and S Shrestha performed all high-throughput and functional experiments and wrote the first draft of the manuscript. H Pan, JD Holbrook and S Shrestha performed the analysis of Infinium HumanMethylation450 BeadChip Array data. CV Joglekar performed the statistical analysis of phenotype data from the cohorts. All authors read and provided critical comments on the manuscript. GR Chandak is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Acknowledgements

The authors thank all the participants of all the cohorts for agreeing to join the study and field staff for their contributions in sample collection and community work. The help of S Bhaskar, KR Mani and ID Mali, CSIR-Centre for Cellular and Molecular Biology, Hyderabad in genomic DNA isolation from blood samples and in managing the DNA samples is sincerely acknowledged. The authors acknowledge major contributions by US Deshmukh, S Rao, S Hirve, P Gupta, DS Bhat, H Lubree, S Rege, P Yajnik and the invaluable community work contributed by T Deokar, S Chaugule, A Bhalerao and V Solat from the KEM Hospital Research Centre, Pune.

Availability of data&material

The summary association statistics from the genome-wide methylation data presented in this study will be made available at the institutional website (www.ccmb.res.in). The results of DMCpGs and DMRs identified in this study using Infinium HumanMethylation450 BeadChip are provided in Supplementary Tables 4–11.

Financial&competing interests disclosure

This work was supported by funds from Council of Scientific and Industrial Research (CSIR), Ministry of Science and Technology, Government of India, India (XII 5-Year Plan titled “EpiHED; BSC0118”). The PMNS cohort and Chikki Trial were initially supported by funds from the Wellcome Trust, London, UK, Medical Research Council, London, UK and Department of Biotechnology (DBT), Ministry of Science and Technology, Government of India, India, respectively. DK Yadav also acknowledges the support of European Union for support under FP7 funded project GEoCoDe for his exchange visit to University of Southampton, Southampton, UK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the man uscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The study was approved by the KEM Hospital Ethics Committee and informed written consent of the parents and informed written assent of the participants has been taken (ref: KEMHRC/VSP/Dir Off/EC/065; Project No. 067).

Additional information

Funding

This work was supported by funds from Council of Scientific and Industrial Research (CSIR), Ministry of Science and Technology, Government of India, India (XII 5-Year Plan titled “EpiHED; BSC0118”). The PMNS cohort and Chikki Trial were initially supported by funds from the Wellcome Trust, London, UK, Medical Research Council, London, UK and Department of Biotechnology (DBT), Ministry of Science and Technology, Government of India, India, respectively. DK Yadav also acknowledges the support of European Union for support under FP7 funded project GEoCoDe for his exchange visit to University of Southampton, Southampton, UK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the man uscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.