In utero exposure to diesel exhaust particulates is associated with alterations of the neonatal cardiomyocyte transcriptome, metabolic parturbation and a global decrease in DNA methylation. [RRBS]

Developmental exposure to particulate matter air pollution is harmful to cardiovascular health, but the mechanisms by which this exposure mediates susceptibility to heart disease is poorly understood. We have previously shown, in a mouse model, that gestational exposure to diesel exhaust results in increased cardiac hypertrophy, fibrosis and susceptibility to heart failure in the adult offspring following transverse aortic constriction. In this study we have found hypomethylation of DNA in neonatal cardiomyocytes isolated from in utero DE exposed neonates. We have demonstrated that in utero exposure to diesel exhaust alters the neonatal cardiomyocyte transcriptional and epigenetic landscapes, as well as the metabolic capability of these cells. Understanding how exposure alters the developing heart through dysregulation of gene expression, metabolism and DNA methylation is vital for identifying therapeutic interventions for air pollution-related heart failure. Overall design: Female mice were paired with male mice for timed mating in FA. After observation of a vaginal plug, pregnant mice were put into FA or DE with exposures beginning at E0.5 and lasting until E17.5, at which point pregnant mice were transferred from the Northlake facility to the UW Medicine South Lake Union SPF vivarium for neonatal sample collection or weaned and kept until 11-12 weeks for adult sample collection. Upon birth, neonatal hearts were harvested, trimmed of surrounding vascular and atrial tissue, and dissociated as previously described. Dissociation was performed using 1mg/mL Liberase TH (Roche; Pleasanton, CA, USA) in 1X HBSS by incubating hearts at 37 degrees for 5 minutes in solution, with pipetting to release cells after incubation. Media containing released neonatal carciomyocytes (NCMs) was adjusted to 20% FBS-DMEM, and cellular dissociation was continued until the majority of cells were released. Cells were then filtered using a 70um sieve, re-eluted in 20% FBS-DMEM with 20uM Ara-C and incubated at 37 degrees for 1 hour to allow fibroblasts to attach onto the plate. After incubation, media with suspended cardiomyocytes was carefully removed, spun and purified cardiomyocyte pellets were collected and frozen at -80°C.