B3603 - Harnessing genetics to understand the role of DNA methylation in healthy aging - 30/10/2020

B number: 
Principal applicant name: 
Josine Min | MRC IEU, University of Bristol
Jonathan Mill , Professor Caroline Relton, Dr. Jordana Bell, Professor Imre Berger, Dr. Gibran Hemani, Professor Tom Gaunt, Dr. Eilis Hannon
Title of project: 
Harnessing genetics to understand the role of DNA methylation in healthy aging
Proposal summary: 

DNA methylation (DNAm) plays a central role in gene regulation. It helps to define how cells respond to environmental signals and, ultimately, contributes to health or susceptibility to disease. However, the amount and the effects of differences in DNAm from one person to another is poorly understood. Understanding DNAm variability is a complex area of research as DNAm varies from one type of cell to another and can change over time. In addition, DNAm is influenced by genetic, molecular and environmental and other factors. So far, most epidemiological studies of DNAm have been performed in blood comprising diverse cell types. Furthermore, it is unknown whether DNAm changes lead to other molecular changes (for example gene expression) or whether the reverse is true, with molecular changes leading to changes in DNAm. Together, this makes the interpretation of DNAm variability difficult.

A powerful avenue into researching the functional consequences of changes in DNAm levels is to correlate DNA sequence variants such as single nucleotide polymorphism (SNPs) to DNAm levels to find both local and distal (for example on other chromosomes) effects. Having completed the largest genetic study of DNAm worldwide to date (through the Genetics of DNA Methylation Consortium) by scanning 10 million SNPs genomewide, we have identified 270k SNP-DNAm associations. This was achieved by analysing about 400,000 DNAm sites in blood, which is only 2% of 28 million DNAm sites across the genome. There is a huge potential for improved understanding of DNAm variation between individuals and its influence on health and disease by studying other regulatory regions of the genome, disease-relevant cell type or context and by developing novel epidemiological approaches where effects of multiple cell types and regulatory features are combined in a population-based setting.

We propose to integrate a suite of state-of-the-art technologies to characterise the functional role of DNAm. We will use novel sequencing technologies based on long reads with the ability to measure all 28 million sites and to determine both the DNAm level and the genotype at single molecule level. We will exploit these properties to provide insights on highly complex genomic regions, differential DNAm between alleles and detection of different modifications. We will systematically map genetic influences on DNAm across a wide range of tissues, cell types and ancestries. We will use this resource to understand the regulatory role of non-coding variants associated with disease traits by studying shared genetic variation and by using genotype as a causal anchor. We will further develop epidemiological approaches to explore the functional role of DNAm variation between individuals in large population-based epidemiology studies. We will validate causal relationships between DNAm sites and traits with epigenetic editing experiments where we manipulate DNAm sites to study the effects of gene regulation to disease. We will establish an openly accessible data resource that will enhance our understanding of environmental and genetic influences on genome function in humans.

Impact of research: 
The epigenome may harbor useful information about life-time exposures and disease risk factors. Large mQTL resources will be of use to the scientific community to elucidate mechanisms of genome regulation, to control for genetic confounding in EWAS, to identify causal pathways between molecular factors and disease risk and to elucidate functional effects of GWAS variants.
Date proposal received: 
Monday, 19 October, 2020
Date proposal approved: 
Thursday, 22 October, 2020
Epigenomics, Healthy aging, Long read methylome sequencing, Epigenetics