In utero exposure to PM2.5 during gestation caused adult cardiac hypertrophy through histone acetylation modification.

Abstract

Ambient particles with a diameter of <2.5 μm (PM2.5) is a global health concern, and exposure to PM2.5 contributes to the progression of cardiovascular morbidity and mortality. In this study, pregnant c57 mice were exposed to PM2.5 during the whole gestation (approximately 300 µg/m 3 PM2.5 for 2 hours/d). A significantly low birth weight was found after in utero PM2.5 exposure, and low body weight continued for 12 weeks after birth. In the offspring, remarkable destructions of cardiac ultrastructures were determined both in newborn and adult hearts. In adulthood, hearts of mice in the PM2.5 exposed group showed cardiac hypertrophy. Protein levels of p300, CBP (histone acetyltransferase), and acetylated histone3 lysine 9 (H3K9ac) increased in the trial group; messenger RNA (mRNA) levels of GATA binding protein 4 (GATA4) and myocyte enhancer factor 2C (Mef2c) (prohypertrophic transcription factors), and mRNA levels of the classic hypertrophic genes, such as α-MHC and β-MHC, increased significantly in the hearts of the PM2.5 exposed group. H3K9ac levels near the promoter region of GATA4 and Mef2c went up in the PM2.5 group. The binding affinities of p300/CBP with promoters of GATA4 and Mef2c increased notably. Taken together, out data indicated that maternal exposure to PM2.5 during gestation may cause a series of cardiovascular events in the offspring; histone acetylation modification may play an important role in the programming of cardiac hypertrophy.