Showing papers by "Lee Murphy published in 2017"
National Institutes of Health1, Harvard University2, Boston University3, University of Edinburgh4, University of Queensland5, Science for Life Laboratory6, University of Alabama at Birmingham7, University of Minnesota8, Johns Hopkins University School of Medicine9, Icahn School of Medicine at Mount Sinai10, University of Texas Health Science Center at Houston11, University of North Carolina at Chapel Hill12, Uppsala University13, Western General Hospital14, Wayne State University15, Children's Hospital Oakland Research Institute16, Stanford University17, University of Kentucky18, Baylor College of Medicine19
TL;DR: BMI-relatedDNA methylation and gene expression provide mechanistic insights into the relationship between DNA methylation, obesity, and adiposity-related diseases.
Abstract: Background
The link between DNA methylation, obesity, and adiposity-related diseases in the general population remains uncertain.
Methods and Findings
We conducted an association study of body mass index (BMI) and differential methylation for over 400,000 CpGs assayed by microarray in whole-blood-derived DNA from 3,743 participants in the Framingham Heart Study and the Lothian Birth Cohorts, with independent replication in three external cohorts of 4,055 participants. We examined variations in whole blood gene expression and conducted Mendelian randomization analyses to investigate the functional and clinical relevance of the findings. We identified novel and previously reported BMI-related differential methylation at 83 CpGs that replicated across cohorts; BMI-related differential methylation was associated with concurrent changes in the expression of genes in lipid metabolism pathways. Genetic instrumental variable analysis of alterations in methylation at one of the 83 replicated CpGs, cg11024682 (intronic to sterol regulatory element binding transcription factor 1 [SREBF1]), demonstrated links to BMI, adiposity-related traits, and coronary artery disease. Independent genetic instruments for expression of SREBF1 supported the findings linking methylation to adiposity and cardiometabolic disease. Methylation at a substantial proportion (16 of 83) of the identified loci was found to be secondary to differences in BMI. However, the cross-sectional nature of the data limits definitive causal determination.
Conclusions
We present robust associations of BMI with differential DNA methylation at numerous loci in blood cells. BMI-related DNA methylation and gene expression provide mechanistic insights into the relationship between DNA methylation, obesity, and adiposity-related diseases.
245 citations
TL;DR: The genetic heritability of a number of complex traits and diseases was partitioned into components due to mQTL and the remainder of the genome and significant enrichment was observed for height, ulcerative colitis, Crohn's disease, and coronary artery disease.
Abstract: DNA methylation plays an important role in the regulation of transcription. Genetic control of DNA methylation is thus a potential candidate for explaining the many identified SNP associations with diseases and complex traits that are not found in coding regions. We identified and replicated 52,916 cis and 2,025 trans DNA methylation quantitative trait loci (mQTL) using methylation measured on Illumina HumanMethylation450 arrays in the Brisbane Systems Genetics Study (n=614 from 177 families) and the Lothian Birth Cohorts of 1921 and 1936 (combined n = 1366). The trans mQTL SNPs were found to be over-represented in the subtelomeric 1Mbp of the genome and on chromosomes 16 and 19. There was a significant increase in trans mQTL DNA methylation sites in upstream and 5' UTR regions. No association was observed between either the SNPs or DNA methylation sites of trans mQTL and telomere length. LD Score regression was used to partition the heritability for a number of complex traits and diseases into components due to mQTL and the remainder of the genome. Significant enrichment was observed for height (p = 2.1x10^-10), ulcerative colitis (p = 2x10^-5), Crohn's disease (p = 6x10^-8) and coronary artery disease (p = 5.5x10^-6) when compared to a random sample of SNPs with matched minor allele frequency. This enrichment is explained by the genomic location of the mQTL SNPs, which are biased towards genic regions of the genome due to the combination of the vast majority being located in cis to the DNA methylation probes and the probes on the array being over-representing genic regions.
53 citations
01 Dec 2017
TL;DR: Gene Ontology enrichment analysis indicated an enrichment of biological processes involved in the immune system in smokers compared to non-smokers and the expression of transcripts for genes previously associated with stress response, autoimmune disease and cancer were associated with telomere length.
Abstract: Gene expression is influenced by both genetic variants and the environment. As individuals age, changes in gene expression may be associated with decline in physical and cognitive abilities. We measured transcriptome-wide expression levels in lymphoblastoid cell lines derived from members of the Lothian Birth Cohort 1936 at mean ages 70 and 76 years. Changes in gene expression levels were identified for 1,741 transcripts in 434 individuals. Gene Ontology enrichment analysis indicated an enrichment of biological processes involved in the immune system. Transcriptome-wide association analysis was performed for eleven cognitive, fitness, and biomedical aging-related traits at age 70 years (N=665 to 781) and with mortality. Transcripts for genes (F2RL3, EMILIN1 and CDC42BPA) previously identified as being differentially methylated or expressed in smoking or smoking-related cancers were overexpressed in smokers compared to non-smokers and the expression of transcripts for genes (HERPUD1, GAB2, FAM167A and GLS) previously associated with stress response, autoimmune disease and cancer were associated with telomere length. No associations between expression levels and other traits, or mortality were identified.
37 citations