Characterization of genome-wide H3K27ac profiles reveals a distinct PM2.5-associated histone modification signature

Abstract

BackgroundCurrent studies of environmental health suggest a link between air pollution components, such as particulate matter (PM), and various diseases. However, the specific genes and regulatory mechanisms implicated in PM-induced diseases remain largely unknown. Epigenetic systems such as covalent modification of histones in chromatin may mediate environmental factors in gene regulation. Investigating the relationships between PM exposure and histone modification status may help understand the mechanisms underlying environment-associated health conditions.MethodsIn this study, we obtained genome-wide profiles of H3K27ac (histone 3 lysine 27 acetylation), known to be an active gene regulatory histone modification marker, in blood samples collected from four Chinese individuals exposed to high or low PM2.5 (particles with diameters up to 2.5 μm).ResultsThe genome-wide chromatin immunoprecipitation sequencing (ChIP-Seq) data indicated a comprehensive differential H3K27ac landscape across the individual genomes, which was associated with high PM2.5. Moreover, a substantial number of these PM2.5-associated differential H3K27ac markers were in genes involved in immune cell activation, potentially linking these epigenetic changes with air pollution-induced immune and inflammatory responses.ConclusionsOur study provides the first genome-wide characterization of H3K27ac profiles in individuals subjected to different exposure levels of PM2.5. Future systematic investigations of the relationships between air pollutants and histone modifications in large population samples are warranted to elucidate the contributions of histone modifications to environment-associated diseases.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-015-0052-5) contains supplementary material, which is available to authorized users.

Traffic-derived particulate matter exposure and histone H3 modification: A repeated measures study

“…We previously observed elevated H3K27ac patterns in individuals from a different population exposed to ambient PM 2.5 in Beijing (Liu et al, 2015a). These inconsistent findings reveal differences between personal and citywide PM exposures.…”

Histone 3 modifications and blood pressure in the Beijing Truck Driver Air Pollution Study

“…In this cohort, while office workers and truck drivers did not differ in short-term or average 14-day levels of PM 10 exposure, truck drivers had significantly greater exposure to PM 2.5 , black carbon, and heavy metals (Sanchez-Guerra et al 2015). As PM 2.5 has been shown to independently increase H3K27me3 markers and risk of hypertension (Coogan et al 2012, Liu et al 2015, Coogan et al 2016), this may also explain our paradoxical finding of a positive association between H3K27me3 and post-work PP among truck drivers. Additionally, metals such as arsenic and nickel have been shown to affect levels of other histone 3 modifications as well as predispose individuals to the development of increased BP and hypertension (Wang et al 2002, Cantone et al 2011, Abhyankar et al 2012, Farzan et al 2015, Jiang et al 2015).…”

“…First, the histone markers were measured in whole blood samples reflecting a mixed cell population, which may limit our ability to understand the exact biological mechanism by specific blood cell type. Nonetheless, whole blood is easy to obtain and process – for this reason most human epigenetic studies use whole blood for epigenetic biomarker measurements, including histone modifications, in the hope of identifying blood-based, cost-effective disease biomarkers (Hou et al 2013, Hou et al 2014, Liu et al 2015, Ma et al 2015, Sanchez-Guerra et al 2015, Hou et al 2016, Zheng et al 2016, Zhang et al 2017). The rationale for our using mixed white blood cells is supported by the need to identify novel biomarkers of BP in easily obtainable blood samples.…”

“…Other influencing factors include ambient air temperature (Chen et al 2013, Lanzinger et al 2014, Martinez-Nicolas et al 2015), biological sex (Briant et al 2016, Joyner et al 2016), smoking habits (Virdis et al 2010, Takami and Saito, 2011, Camplain et al 2016), and occupational hazards (Guimont et al 2006, Trudel et al 2016). Epigenetic factors such histone modifications are additionally sensitive to these factors (Liu et al 2015), but may represent a more stable biomarker of underlying cardiovascular health, as estimated by morning blood pressure measurements. Identification of a stable biomarker which represents resting-state BP would be useful in clinical practices due to the reduction in measurement error.…”

Predictive and Prognostic Biomarkers of Respiratory Diseases due to Particulate Matter Exposure

“…Biomarkers can be used for disease prediction 35. Various epigenetic biomarkers of lung diseases induced by PM exposure have been discovered in recent researches 36,37. Epigenetic changes do not alter the DNA sequences.…”