Establishing the influence of pollutants on genome function is essential in defining their impact on human health. Arsenic is a ubiquitous environmental toxic metalloid that leads to carcinogenesis. The World Health Organization estimates that over 100 million people worldwide are at risk to drinking arsenic contaminated water. Recent studies indicate that arsenic alters gene expression leading to tumorigenesis. Proper gene regulation is essential for normal growth, development and etiology of diseases such as cancer. Eukaryotic DNA stored as chromatin whose basic repeating unit is the nucleosome, plays an integral role in gene regulation. Previously, we (and others) showed that nucleosome locations within promoters play critical roles in chromatin accessibility, thus controlling gene activity. Consequently, chromatin accessibility is an essential component in gene regulation yet is not fully understood. Chromatin accessibility appears to be modulated by several key epigenetic factors: histone post-translational modifications (PTMs), DNA methylation, nucleosome position/occupancy, transcription factors and chromatin architectural proteins (CAPs). Recent studies now indicate that changes in DNA methylation and histone PTMs influence gene expression in response to arsenic: Thus it is critically important to understand how these key epigenetic modulators integrate and interrelate to regulate the chromatin state and gene expression during arsenic exposure. This project will determine the functional changes in gene regulation, chromatin composition, structure and dynamics genome-wide due to arsenic in normal and iAs- transformed cells. We hypothesize that iAs-induced alterations in nucleosome position and occupancy, histone PTMs, and CAP occupancy all combine to dynamically restructure chromatin resulting in differential expression of key genes resulting in a failure to ensure proper gene regulation and cancer. We propose in this application the following Specific Aims: (1) determine the effect of iAs on in vivo nucleosome positioning and/occupancy during iAs-induced transformation. (2) Determine the impact of iAs- triggered modulation of CAPs-chromatin structure to impact gene expression. (3) Determine the mechanisms whereby iAs-provoked changes in chromatin composition, structure and dynamics control TF occupancy. Our interdisciplinary, broad approach will establish unique comprehensive functional and mechanistic data that will provide a detailed understanding of the interplay between arsenic-induced epigenetic changes and chromatin in the mammalian cell. We have developed novel systems that will provide an unprecedented and unique opportunity to discover the functional and mechanistic roles of the epigenome in toxin-induced diseases.

Public Health Relevance

Proper regulation of gene expression is essential to the development and health of all organisms. The DNA in each eukaryotic cell, found as chromatin plays an integral part in this gene regulation. Indeed where nucleosomes are located is important in our understanding of gene regulation. Furthermore knowing how chromatin structure responds to particular stimuli to control the on and off state of genes would be helpful in the development of new diagnostic and therapeutic tools.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES024478-03
Application #
9210628
Study Section
Special Emphasis Panel (ZRG1-DKUS-C (90))
Program Officer
Tyson, Frederick L
Project Start
2015-04-07
Project End
2020-01-31
Budget Start
2017-02-01
Budget End
2018-01-31
Support Year
3
Fiscal Year
2017
Total Cost
$369,895
Indirect Cost
$109,314
Name
University of Kentucky
Department
Biochemistry
Type
Schools of Medicine
DUNS #
939017877
City
Lexington
State
KY
Country
United States
Zip Code
40506
Rea, Matthew; Gripshover, Tyler; Fondufe-Mittendorf, Yvonne (2018) Selective inhibition of CTCF binding by iAs directs TET-mediated reprogramming of 5-hydroxymethylation patterns in iAs-transformed cells. Toxicol Appl Pharmacol 338:124-133
Eckstein, Meredith; Rea, Matthew; Fondufe-Mittendorf, Yvonne N (2017) Microarray dataset of transient and permanent DNA methylation changes in HeLa cells undergoing inorganic arsenic-mediated epithelial-to-mesenchymal transition. Data Brief 13:6-9
Melikishvili, Manana; Matveeva, Elena; Fondufe-Mittendorf, Yvonne (2017) Methodology to Identify Poly-ADP-Ribose Polymerase 1 (PARP1)-mRNA Targets by PAR-CLiP. Methods Mol Biol 1608:211-228
Rea, Matthew; Eckstein, Meredith; Eleazer, Rebekah et al. (2017) Genome-wide DNA methylation reprogramming in response to inorganic arsenic links inhibition of CTCF binding, DNMT expression and cellular transformation. Sci Rep 7:41474
Eckstein, Meredith; Rea, Matthew; Fondufe-Mittendorf, Yvonne N (2017) Transient and permanent changes in DNA methylation patterns in inorganic arsenic-mediated epithelial-to-mesenchymal transition. Toxicol Appl Pharmacol 331:6-17
Martin, Rebecca L; Maiorano, John; Beitel, Greg J et al. (2017) A comparison of nucleosome organization in Drosophila cell lines. PLoS One 12:e0178590
Eckstein, Meredith; Eleazer, Rebekah; Rea, Matthew et al. (2017) Epigenomic reprogramming in inorganic arsenic-mediated gene expression patterns during carcinogenesis. Rev Environ Health 32:93-103
Riedmann, Caitlyn; Fondufe-Mittendorf, Yvonne N (2016) Comparative analysis of linker histone H1, MeCP2, and HMGD1 on nucleosome stability and target site accessibility. Sci Rep 6:33186
Rea, Matthew; Jiang, Tingting; Eleazer, Rebekah et al. (2016) Quantitative Mass Spectrometry Reveals Changes in Histone H2B Variants as Cells Undergo Inorganic Arsenic-Mediated Cellular Transformation. Mol Cell Proteomics 15:2411-22
Matveeva, Elena; Maiorano, John; Zhang, Qingyang et al. (2016) Involvement of PARP1 in the regulation of alternative splicing. Cell Discov 2:15046

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