Douglas Bell, Ph.D.
Immunity Inflammation and Disease Laboratory / Environmental Epigenomics and Disease Group
B352 Rall Building
111 T W Alexander Dr
Research Triangle Park, NC 27709
The Environmental Epigenomics Group works to characterize underlying factors that contribute to variability in human toxicological responses. We especially focus on discovery of human alleles or epigenetic factors that mediate responses to exposure and we investigate how such factors affect risk in exposed people. This basic information will be useful in determining appropriate variability parameters in human risk estimation models, in identifying at-risk individuals and in devising disease-prevention strategies.
The NIEHS Environmental Genome Project, the 1000 Genomes Project and Roadmap Epigenome Project have uncovered millions of sequence variants and epigenetic features in the human genome. However, the relationship between these factors and transcriptional response to environmental stress is still unclear and methods for studying this are not established. The Environmental Epigenomics Group is developing novel methods to identify SNPs or epigenetic states that regulate transcription profiles and functional impact in vitro and in vivo. Thus, the group's overall objective is to identify sequence variants and epigenetic features that mediate exposure responses and to evaluate their roles in human susceptibility to environmentally-induced disease using a variety of functional approaches.
Epigenetics is the nongenetic transmission of gene regulation information from parent cell to daughter cells and from one generation to the next that is encoded in methyl-CpGs, histone modifications or noncoding RNAs. Epigenetic factors such as chromatin state may modulate the impact of exposure, or conversely, exposure can directly alter epigenetic status such as DNA methylation level in regulatory sequences (Joubert et al 2012). Determining the functional impact of exposure-induced changes in methylation is an active area of interest for our group.
Major Areas of Research:
- Identification of epigenetic factors and sequence variants that modulate exposure responses regulated by the Ah receptor (carcinogen metabolism), NRF2 (oxidative stress), and p53 (DNA damage)
- Evaluation of the role of these factors in exposed individuals and in environmentally-induced disease
- Computational discovery and functional analysis of p53, AhR, and NRF2 transactivation target sequences (response elements) to assess the impact of SNPs on regulation of responsive genes and role in disease (Noureddine et al., 2009; Wang et al., 2011, 2016; Zeron-Medina et al., 2013; Stracquadanio G et al 2016). Understanding the role of chromatin state, dynamics, and methylation status on exposure-induced transcription of genes in the p53, AhR and NRF2 pathways (Su et al., 2014).
- Identifying exposure-induced methylation patterns in blood cell DNA (Joubert et al 2012; Su et al 2016; Wan et al 2018). A collaboration with Dr. Stephanie London (Epidemiology Branch) discovered that maternal smoking produces highly significant (p<10-15) changes in the methylation status of genes in fetal cord blood (Joubert et al., 2012). In adult smokers we see similar tobacco exposure-induced methylation patterns in their blood cells (Reynolds et al 2015; Su et al 2016) and we are determining the usefulness of these patterns as biomarkers of tobacco exposure (Reynolds et al, 2018). Using single cell sequencing and cell separation techniques combined with whole genome methylation analysis and RNA-seq we are examining the impact of exposure on hematopoietic cells from adults and neonates (Wan et al, 2018) and investigating the mechanism driving these changes.
- In a collaboration with the CDC and NCI we are examining DNA methylation in the individuals participating in the Anniston Community Health Survey I and II (ACHS I, II) cross-sectional studies that were conducted from 2005-2007 and 2014. We hypothesize that PCBs and other persistent organic pollutant (POP) exposures in Anniston’s population may alter DNA methylation and associate with adverse health outcomes.
Dr. Bell received a B.S. degree from Cornell University in 1975, and a Ph.D. in Environmental Biology from the University of North Carolina at Chapel Hill in 1988. Following postdoctoral fellowships at UNC-CH and U.S. Environmental Protection Agency he joined the National Institute of Environmental Health Sciences in 1990 becoming a Senior Investigator in 1996. He currently heads the Environmental Epigenomics Group in the Immunity Inflammation and Disease Laboratory, NIEHS.
Bell DA, Taylor JA, Paulson DF, Robertson CN, Mohler JL, Lucier GW. Genetic risk and carcinogen exposure: a common inherited defect of the carcinogen-metabolism gene glutathione S-transferase M1 (GSTM1) that increases susceptibility to bladder cancer. J Natl Cancer Inst. 1993;85(14):1159-64.
Stracquadanio G, Wang X, Wallace MD, Grawenda AM, Zhang P, Hewitt J, Zeron-Medina J, Castro-Giner F, Tomlinson IP, Goding CR, Cygan KJ, Fairbrother WG, Thomas LF, Sætrom P, Gemignani F, Landi S, Schuster-Böckler B, Bell DA, Bond GL. The importance of p53 pathway genetics in inherited and somatic cancer genomes. Nat Rev Cancer. 2016;16(4):251-65.
Zeron-Medina J, Wang X, Repapi E, Campbell MR, Su D, Castro-Giner F, Davies B, Peterse EF, Sacilotto N, Walker GJ, Terzian T, Tomlinson IP, Box NF, Meinshausen N, De Val S, Bell DA, Bond GL. A polymorphic p53 response element in KIT ligand influences cancer risk and has undergone natural selection. Cell. 2013;155(2):410-22.
Reynolds LM, Wan M, Ding J, Taylor JR, Lohman K, Su D, Bennett BD, Porter DK, Gimple R, Pittman GS, Wang X, Howard TD, Siscovick D, Psaty BM, Shea S, Burke GL, Jacobs DR Jr, Rich SS, Hixson JE, Stein JH, Stunnenberg H, Barr RG, Kaufman JD, Post WS, Hoeschele I, Herrington DM, Bell DA, Liu Y. DNA Methylation of the Aryl Hydrocarbon Receptor Repressor Associations With Cigarette Smoking and Subclinical Atherosclerosis. Circ Cardiovasc Genet. 2015;8(5):707-16.
Wang X, Campbell MR, Lacher SE, Cho HY, Wan M, Crowl CL, Chorley BN, Bond GL, Kleeberger SR, Slattery M, Bell DA. A Polymorphic Antioxidant Response Element Links NRF2/sMAF Binding to Enhanced MAPT Expression and Reduced Risk of Parkinsonian Disorders. Cell Rep. 2016.
Related Scientific Focus Areas
Genetics and Genomics
Molecular Biology and Biochemistry
This page was last updated on September 12th, 2018