Toxicology

Epigenetics in environmental toxicology

The fact that environmental factors induce DNA mutations that may lead to disease is well-established and will have tremendous benefits when incorporated into various environmental safety and health assessments. Environmental factors such as dietary intake, drugs, stress, or exposure to toxins, can cause epigenetic changes by possibly altering how transcription factors bind to DNA or changing the structure of the histones that DNA wraps around. These structural changes can affect gene activity or gene expression. A number of environmental factors have been investigated for their effect on epigenetic changes including phthalates, toxic metals, smoking, air pollution, jet fuel, environmental stress, and a high fat diet. Effects on epigenetic mechanisms, DNA methylation patterns, histone modifications, miRNA expression have been documented as a result. The table below (Marczylo et al, 2016 and Society of Toxicology, 2018) summarizes a few of the studies that have been done for putative environmentally-induced epigenetic toxicity in humans or rat/mouse.

In the future, incorporating epigenetic evaluation into toxicity tests can increase the safety of both food and environmental substances.

Toxin/exposure	Species/stage of exposure/effect	Phenotype	Epigenetic change	Reference(s)
Air pollution	Human/childhood/childhood	Asthma	Epigenetic mechanisms	Somineni et al. (2016)
BPA	Human/in utero/childhood	Behavior	DNA methylation	Kundakovic (2015)
Formaldehyde	Human/lifetime/adult	Alzheimer’s	Epigenetic mechanisms and DNA methylation	Tong et al. (2015)
Methylmercury	Rodent/in utero/adult	Behavior	Histone modifications and DNA methylation	Onishchenko (2008)
Arsenic	Human/lifetime/adult	Skin disorder	DNA methylation	Paul et al. (2014)
Nickel	Human/lifetime/adult	NSCLC survival	miRNA	Chiou et al. (2015)
Polycyclic aromatic hydrocarbons	Human/adult/adult	Chromosome aberrations - PBL	DNA methylation	Yang et al. (2012)
Various phthalates	Rodent/in utero/adult	Decreased testosterone/gonadal	DNA methylation and histone modifications	Kilcoyne et al. (2014) Martinez-Arguelles et al. (2009), Papoutsis et al. (2015), Takeda et al. (2012), Yoshioka et al. (2011)
Smoking	Human/Lifetime/adult	COPD and tumor	Epigenetic mechanisms, DNA methylation, miRNA	Lin (2010), Ostrow (2013) Shenker (2013), Xie et al. (2014)
Alcohol	Rodent/lifetime and in utero	Nuerological, cardiac, behavior, stem cell	Histone modification and miRNA	Ignacio et al. (2014), Middleton et al. (2012), Leu et al. (2014), Pascual et al. (2011), Peng et al. (2015)
High fat diet	Rodent/in utero/adult	Diet preference	DNA methylation and miRNAs	Baselga-Escudero (2015), Carlin et al. (2013), Vucetic et al. (2010)
Under-nourishment	Rodent/adult/adult	Hepatic	miRNAs	Tryndyak et al. (2016)